Lirong Liu

Dr Lirong Liu

+44 (0)1483 689271
15 BA 02
Tuesdays from 3pm - 4 pm

Academic and research departments

Centre for Environment and Sustainability.



Research interests

Research projects


Postgraduate research supervision




Please see my Google Scholar page for more information: Lirong Liu

Ishanki De Mel, Floris Bierkens, Xinyao Liu, Matthew Leach, Mona Chitnis, Lirong Liu, Michael Short (2023)A decision-support framework for residential heating decarbonisation policymaking, In: Energy268126651 Elsevier

The decarbonisation of residential heating systems has become increasingly important to meet the global goals of minimising carbon emissions and combating climate change. However, with rising energy costs, this can be a significant challenge for low-income households. This study presents a novel optimisation framework to aid the decarbonisation of residential heating in the United Kingdom by combining technology-related decision-support with policy decisions. The framework can recommend the optimal retrofit of low-carbon heating technologies and fabric improvement measures such as insulation upgrades for improving energy efficiency. Concurrently, the optimal financial contributions towards investment costs from grants supporting low-income households and social housing is determined. It also includes piecewise linearisations to capture the detailed operation of air source heat pumps, which are set to replace natural gas-based heating systems, and assesses the eligibility of each dwelling for grant funding. A large case study consisting of social housing stock in Woking, UK, has been used to test the framework. Three scenarios are used to assess the efficacy of existing technology and policy combinations to meet local emissions reduction targets, which are benchmarked against emissions from existing gas-based heating systems and insulation measures. Results highlight the limitations of existing UK grants, as these can only achieve an emissions reduction of 33.5% without incurring significant additional investment costs to the local council. The lack of support towards installing hot water tanks, which are required for the operation of heat pumps, is another major limitation in existing grants. A proposed scenario, which introduces a fictional grant with unlimited funding, sheds light on the much larger grant contributions expected to achieve an emissions reduction of 66.8%, which surpasses local targets. These results also suggest the need for operational support to cope with much higher energy bills, especially for low-income and/or fuel-poor households, due to the electrification of heating systems. Overall, the framework is a useful tool for local councils, policy makers, and other stakeholders to make informed decisions on the affordable decarbonisation of residential heating systems.

Mengyu Zhai, Guohe Huang, Lirong Liu, Xinli Xu, Jizhe Li (2018)Transfer of virtual water embodied in food: A new perspective, In: Science of The Total Environment659pp. 872-883 Elsevier

Food and water are inextricably linked. With the increase of water consumption in irrigation and food growth, water shortage has become an urgent issue. Irrational cross-regional transfer of water embodied in food exacerbates water scarcity and restrict China's sustainable development. Given that, a Virtual Water-Food Nexus Model is developed to quantify the inter-provincial transfer of water embodied in food and to identify the complicated interactions between different provinces. In detail, Environmental Input-Output Analysis is applied to quantitatively estimate the inter-provincial water transfer embodied in food trades. Based on the network constructed by interrelated nature of nexus, the mutual interactions, control situation, and the dominant and weak pathways are examined through the combination of Ecological Network Analysis and Principal Component Analysis. Two new indictors water consumption intensity and water supply capacity are first performed to measure the role of each province from the supply and consume side respectively. It is revealed that interregional food transactions failed to realize water resources dispatching management. Many water-deficient regions suffered from massive virtual water losses through food exports, but water-rich areas still import large quantities of food containing virtual water. Results show that exploitation and competition dominate the ecological relationships between provinces. Agricultural GDP ratio is the indicator which most affect water consumption intensity and water supply capacity. Network-based research contributes more insights into the recognition of water management responsibilities across provinces and municipalities. These findings will provide a scientific support to adjust unreasonable allocation of water resources in China in an attempt to addressing the contradiction between food demand and water shortages.

Guo Zhang, Guohe Huang, Lirong Liu, Geng Niu, Jizhe Li, Edward McBean (2019)Ecological network analysis of an urban water metabolic system based on input-output model: A case study of Guangdong, China, In: Science of The Total Environment670pp. 369-378 Elsevier

When considering a region as a superorganism, there are various processes of metabolism that reflect the growth and maintenances of the system, as well as the interactions with the surroundings. Ecological Network Analysis combined with the input-output model is utilized to analyze the water consumption structure and the interaction control relationships among different sectors within the urban ecosystem. The integrated approach is applied to the case study of Guangdong Province, China. The Water Ecological Network model is developed by the monetary I-O table of Guangdong province in 2012. The network control analysis is employed to describe the pathway of indirect water. In addition, the competitive and mutual relationship among different sectors is concluded by the approach of network utility analysis. This study also newly compares “virtual water (which is the indirect water) imports of per unit Gross Domestic Product (GDP)” and “water consumption of per unit GDP” to reveal which of them contributes more to the urban metabolism. The results indicate that the top three controllers are machinery, equipment and other services, followed closely by food and tobacco processing. The model results also show that the negative effects among different sectors accounting for the majority in all relationships, which indicates that the system under investigation is not in a mutualism state. This is due to that the competition of water uses between the economic sectors weaken the virtual water circulation within the system. The results are valuable to provide scientific suggestions for improving water use efficiency and make reasonable virtual water policy.

Mengyu Zhai, Guohe Huang, Lirong Liu, Xinli Xu, Yuru Guan, Yupeng Fu (2020)Revealing environmental inequalities embedded within regional trades, In: Journal of Cleaner Production264 Elsevier

Carbon emissions embodied in interprovincial trade (CEE-IT) are closely related with the environmental responsibility allocation. Besides the perspective of administrative division, more rational and effective clusters based on provincial characteristics is more conducive for understanding the regional emission reduction linkages and simplifying the steps of responsibility determination. To provide a reasonable management of CEs transference mitigation in China, this study develops a provincial clustering scale CEE-IT model through three-scale accountings (i.e., aggregated-scale, consumption-scale and income-scale analysis). Specifically, 30 provinces are aggregated into several new regions with similar characteristics. Carbon emissions from different energy sources are first considered to distinguish and specify different emission reduction modes. The input output analysis (IOA) and structural decomposition analysis (SDA) are applied to quantify the embodied interprovincial carbon emissions and the relative contributions of socio-economic factors at the sector-level of disaggregation and aggregation, respectively. Three-scale accountings are innovatively employed into EEBT model to deeply analyze the emissions along China’s domestic inter-regional supply chains for identifying regional production, consumption and income-based emission responsibilities. Based on three accounting perspectives, the results provide suggestions for coordinated emission reduction across regions (including specific provinces) from the overall and decomposition levels. It shows that cutting the imports of mining sector for all regions could reduce emissions from the supply side. Rural household consumption and fixed capital formation are the major drivers for Ⅳ region from the consumption side. Technological innovations in Ⅲ region have reduced carbon emissions by 55.2% and contributed 159 Mt reductions from 2007 to 2012. Ⅲ region is insensitive to energy types and the utilization of crude oil in Ⅰ region limit the improvement of its system efficiency. Importing large quantities of emission-intensive products from Beijing and Jiangsu is a cause of high income-based emissions in Ⅱ region.

X. T. Zeng, G. H. Huang, Y. P. Li, J. L. Zhang, Y. P. Cai, Z. P. Liu, L.R Liu (2016)Development of a fuzzy-stochastic programming with Green Z-score criterion method for planning water resources systems with a trading mechanism, In: Environmental Science and Pollution Research23(24)pp. 25245-25266 Springer

This study developed a fuzzy-stochastic program-ming with Green Z-score criterion (FSGZ) method for waterresources allocation and water quality management with atrading-mechanism (WAQT) under uncertainties. FSGZ canhandle uncertainties expressed as probability distributions,and it can also quantify objective/subjective fuzziness in thedecision-making process. Risk-averse attitudes and robustnesscoefficient are joined to express the relationship between theexpected target and outcome under various risk preferences ofdecision makers and systemic robustness. The developedmethod is applied to a real-world case of WAQT in theKaidu-Kongque River Basin in northwest China, where aneffective mechanism (e.g., market trading) to simultaneouslyconfront severely diminished water availability and degradedwater quality is required. Results of water transactionamounts, water allocation patterns, pollution mitigationschemes, and system benefits under various scenarios are an-alyzed, which indicate that a trading-mechanism is a more sustainable method to manage water-environment crisis inthe study region. Additionally, consideration of anthropogenic(e.g., a risk-averse attitude) and systemic factors (e.g., therobustness coefficient) can support the generation of a robustplan associated with risk control for WAQT when uncertaintyis present. These findings assist local policy and decisionmakers to gain insights into water-environment capacity plan-ning to balance the basin’s social and economic growth withprotecting the region’secosystems

Lirong Liu, Charley Z. Huang, Guohe Huang, Brian Baetz, Scott M. Pittendrigh (2018)How a carbon tax will affect an emission-intensive economy: A case study of the Province of Saskatchewan, Canada, In: Energy159pp. 817-826 Elsevier

A carbon tax has been proposed or applied in many countries and regions around the world to reduce greenhouse gas (GHG) emissions. In this study, a Computable General Equilibrium (CGE) model for the Province of Saskatchewan is first developed to examine and analyze a series of direct and indirect socio-economic impacts of a carbon tax. The energy sector is further disaggregated based on the production structure and energy use pattern to obtain robust results. Different carbon tax rates are simulated to quantify the inter-relationships of the carbon tax, GHG emission reduction, and economic growth. In-depth examinations are also conducted to investigate some other macroeconomic impacts and responses from specific economic sectors. The results show that the GDP change is mainly caused by consumption reduction and import increases, due to the income decline and relatively low tariff rates. Changes in coal and petroleum product production and processes result in the greatest GHG emissions among all sectors. This suggests that clean coal and petroleum technologies may be the crucial issues for realizing both national and provincial environmental and economic objectives. It is expected that the results will provide a solid basis for supporting the application of an effective Pan-Canadian carbon pricing strategy.

Lirong Liu, Guohe Huang, Brian Baetz, Yuru Guan, Kaiqiang Zhang (2019)Multi-Dimensional Hypothetical Fuzzy Risk Simulation model for Greenhouse Gas mitigation policy development, In: Applied Energy261114348 Elsevier

Changing climate is one of the most challenging environment issues worldwide. The objective of this paper is to develop a Multi-Dimensional Hypothetical Fuzzy Risk Simulation Model to facilitate the Greenhouse Gases mitigation policy development and multi-dimensional risk simulation. In detail, the comprehensive performances of various industries are evaluated and analyzed through Hypothetical Extraction Method. The preferences of decision-makers are considered through Analytic Hierarchy Process and Fuzzy Technique for Order Preference by Similarities to Ideal Solution method to develop the optimized Greenhouse Gases mitigation policies. The multi-dimensional risks of optimized Greenhouse Gases mitigation policies are simulated through RAS method. A detailed case study of the Province of Saskatchewan, Canada, is conducted to illustrate the potential benefits of the proposed model and support the Greenhouse Gases mitigation policy development. It is found that Electric power generation, transmission and distribution sector is the key industry in Saskatchewan. The government supports are suggested to be allocated to the Electric power generation, transmission and distribution sector, since it will benefit the province from environmental, economic, and urban metabolic perspectives.

Kaiqiang Zhang, Na Jia, Lirong Liu (2018)Adsorption Thicknesses of Confined Pure and Mixing Fluids in Nanopores, In: Langmuir34(43)pp. 12815-12826 American Chemical Society

In this paper, adsorption thicknesses of confined pure and mixing fluids in nanopores are quantitatively determined and their influential factors are specifically evaluated. First, a new analytical formulation is developed thermodynamically to calculate the adsorption thicknesses. Second, a new generalized equation of state (EOS), which considers the confinement effect-induced phenomena, is developed analytically for calculating the thermodynamic confined fluid phase behavior. Third, the modified model based on the generalized EOS and coupled with the parachor model is applied to calculate the vapor–liquid equilibrium (VLE) and fluid adsorptions for the pure CO2, alkanes of C1–C10, and two mixtures of CO2–C10H22 and CH4–C10H22 in nanopores. Finally, the following five important factors are studied to evaluate their effects on the adsorption thickness: temperature, pressure, pore radius, wall-effect distance, and feed gas-to-liquid ratio (FGLR). The proposed modified EOS is found to be accurate for the VLE and adsorption isotherm calculations. The adsorption thicknesses of confined pure or mixing alkanes are increased with the increasing carbon number but decreased with the temperature increase. For the alkanes of C1–C10, the degree of temperature effect is strengthened with the carbon number increase. Moreover, the adsorption thicknesses are significantly decreased with the pore radius increase until rp = 50 nm, after which they have slight changes or are even constant at any pore radii. On the other hand, the wall-effect distance (δp) increase causes the adsorption thickness to be linearly increased at δp/rp ≥ 0.02. In addition, the effects of the FGLR and pressure on the adsorption thicknesses at the nanoscale are found to be negligible.

Chengyu He, Guohe Huang, Lirong Liu, Xinli Xu, Yongping Li (2019)Evolution of virtual water metabolic network in developing regions: A case study of Guangdong province, In: Ecological Indicators108105750 Elsevier

Rapid urbanization has challenged the utilization and the circulation of water, especially in rapidly developing regions. It is necessary to disaggregate virtual water metabolic networks (VWMN) in representative areas, and examine their relevant dynamics to sustain regional development. In this study, the VWMN of Guangdong Province, China is developed to explore the ecological relationships between pairwise components and identify the ecological hierarchy structure of VWMN. Particularly, the structural analysis of VWMN is optimized and two indicators are proposed in this study. The integral virtual water recycling index (IVWRI) enable to reveal the extent that components are benefited from the existence of the VWEN and the integral virtual water productivity (IVWP) can identify economic output per unit integral virtual water utilization of each component. The results indicate that the tertiary industry fails to promote the development of its upstream industries, and the integral virtual water productivity of this industry is declining. Technology upgrading of manufacturing industry and steady import of primary products are imperative. Moreover, petroleum, coking, nuclear-fuel and construction industries are key components that clog the studied VWMN. This research provides scientific support for the robust development of VWMN, particularly in alleviating water scarcity and promoting sustainable regional development.

J. Zhang, L.R Liu, X. C. Shi, H. Wang, G. H. Huang (2016)Environmental Information in Modern Fiction and Ecocriticism, In: Journal of Environmental Informatics30(1)pp. 41-52 International Society for Environmental Information Sciences (ISEIS)

Environmental writing and ecocritical inquiry have been practiced more vigorously in recent years than before, with increasing sophistication and substantial progress. In this study, the discourses of environment in modern fiction are examined from an ecocritical perspective. The literary representations of environment in modern fiction reveal new insights into environmental issues and provide new perspectives and viable documentary information for the scientific study of the environment. Trying to conceptualize some of the environmental phenomena, this study concludes that zoomorphism and anti-anthropocentrism can well balance ecocentric concerns, reflecting and enhancing the close ties and interdependence between human society and the natural world. Environmental apocalypticism is another notable concept conveyed in modern fiction, indicating great crises of the worsening environment. More importantly, environmental apocalypticism serves as an alarming reminder that the remarkable complexity of problematic environmental issues humans facing are both urgent and devastating. With analyses of literature’s engagement with the natural environment, the interdisciplinary vision highlights the interconnections between man and nature, expands research space for both disciplines and provides more efficient means of solving the environmental problems.

Kaiqiang Zhang, Na Jia, Lirong Liu (2020)Quantitative distinction of thermodynamic soluble and miscible states, In: AIChE Journal66(6) Wiley

Soluble and miscible states are two important thermodynamic states in academic research and practical applications but their quantitative distinctions are still fuzzy. In this study, for the first time, the mathematical formulations of the quantitative criteria for distinguishing the thermodynamic soluble and miscible states are analytically developed by means of the Flory–Huggins solution theory and solubility parameter. The quantitative bottom and upper solubility limits for a total of 13 binary and ternary mixtures are calculated at different conditions. Moreover, the composition, temperature and pore radius are specifically studied to evaluate their effects on the soluble and miscible states. On the basis of the work from this study, the insoluble, soluble but immiscible, and miscible states are definitively quantified and clearly distinguished for the first time.

Lirong Liu, Guohe Huang, Brian Baetz, Charley Z. Huang, Kaiqiang Zhang (2018)A factorial ecologically-extended input-output model for analyzing urban GHG emissions metabolism system, In: Journal of Cleaner Production200pp. 922-933 Elsevier

Increasing urbanization in the world brings tremendous social, economic and environmental challenges. It is essential to fully analyze urban GHG emissions metabolism systems to reveal economic emissions reduction pathways and support sustainable development. In this study, a factorial-based ecologically-extended input-output (FEEIO) model is developed to facilitate urban GHG emissions metabolism analysis. A special case study of the Province in Saskatchewan, Canada, is conducted to illustrate the potential benefits of its use in urban metabolism system health diagnosis. A factorial analysis is introduced to further investigate the effects of the main factors and their interactions. It is found that an urban GHG emissions metabolism system differs from other metabolism systems in regards to its special structure. A high efficiency represents limited emissions pathways in an urban GHG emissions metabolism system, which further provides good opportunities to realize GHG emissions mitigation. In the Province of Saskatchewan, the urban GHG emissions system has high redundancy and low efficiency across twenty scenarios. The GHG emissions from other sources are much simpler than emissions from coal, which further indicates that the emissions from other sources are easier to control through technology improvements or industrial regulations for specific sectors.

Yuru Guan, Guohe Huang, Lirong Liu, Mengyu Zhai, Boyue Zheng (2019)Dynamic analysis of industrial solid waste metabolism at aggregated and disaggregated levels, In: Journal of Cleaner Production221pp. 817-827 Journal of Cleaner Production

Greater efforts should be made for the prevention and treatment of industrial solid waste (ISW). This study models an integrated ISW metabolism framework to explore socio-economic factors of ISW production changes for a case study of Guangdong province, China during 2002–2015. In detail, index decomposition analysis is innovatively conducted to quantify the relative contribution of socio-economic factors to ISW production changes. Waste metabolism input-output analysis is used to reveal internal structure of the system. More specifically, based on a new four-way classification method, components' dependence on the system are determined by linkage analysis. Using environmental responsibility analysis, their environmental responsibilities are assessed. The results show that decreasing ISW generation intensity and further optimizing industrial structure is the only way to Guangdong's ISW reduction at an aggregated sector-level. At a disaggregated sector-level, mining (M) is a key sector and should focus on income-based ISW regulations. Energy and materials transformation (ET) roles as a direct producer and has strong linkages to other sectors. As the largest final consumer, the others (OS) sector should consider consuming less ISW-intensive commodities.

Kaiqiang Zhang, Na Jia, Songyan Li, Lirong Liu (2018)Thermodynamic phase behaviour and miscibility of confined fluids in nanopores, In: Chemical Engineering Journal351pp. 1115-1128 Elsevier

In this paper, thermodynamic phase behaviour and miscibility of confined pure and mixing fluids in nanopores are studied. First, a semi-analytical equation of state (EOS) is developed, based on which two correlations are modified to predict the shifts of critical temperature and pressure. Second, the thermodynamic free energy of mixing and solubility parameter are derived, quantitatively calculated, and applied to study the conditions and characteristics of the fluid miscibility in nanopores. Third, an improved EOS model with the modified correlations is proposed and used to calculate the phase properties and miscibility-associated quantities of three mixing fluids. The critical temperature and pressure of confined fluids are always decreased by reducing the pore radius. The negative pressure state is validated for a confined liquid, whose upper temperature limit is quantitatively determined and found to be lowered with the reduction of pore radius. The liquid–gas miscibility is beneficial from the pore radius reduction and the intermediate hydrocarbons (e.g., C2, C3, i- and n-C4) perform more miscible with the liquid C8 in comparison with the lean gas (e.g., N2 and CH4). Moreover, the molecular diameter of single liquid molecule is determined to be the bottom limit, the pore radius above which is concluded as a necessary condition for the liquid–gas miscibility. The calculated phase behaviour and minimum miscibility pressures (MMPs) of the three mixing fluids agree well with the literature results, which reveals that the shifts of critical properties dominate the phase behaviour and miscibility changes of confined fluids from bulk phase to nanopores.

Lirong Liu, Gordon Huang, Brian Baetz, Guanhui Cheng, Scott M. Pittendrigh, Siyue Pan (2019)Input-output modeling analysis with a detailed disaggregation of energy sectors for climate change policy-making: A case study of Saskatchewan, Canada, In: Renewable Energy151pp. 1307-1317 Renewable Energy

Systematically evaluating the emission intensity and total emission of industries is indispensable for understanding energy and environmental sector performance in general and to support scientific climate change policy-making. In this study, an environmentally extended input-output (EEIO) model with a detailed disaggregation of energy sectors is developed to investigate the life-cycle environmental impacts of different industries. A special case study of the Province of Saskatchewan, Canada, is conducted to illustrate the potential benefits of its use in the environmental policy-making field. The I–O table is transformed and disaggregated based on the energy use patterns and the underlying economic structure. Key GHG emissions, including CO2, CH4 and N2O, are considered and the CO2 equivalent intensities of different economic sectors are calculated. An in-depth analysis of key industries is conducted to further investigate the interactions between different industries. It is founded that the Province of Saskatchewan is a trade exposed and emission intense economy. The emission intensity of agriculture is higher than the mean level, and is difficult to reduce due to the large farm machines used in agricultural production. Fossil-fuel electric power generation, as an intermediate input, has a strong effect on other industries and is a key factor for emission reduction.

Mengyu Zhai, Guohe Huang, Lirong Liu, Shuai Su (2018)Dynamic input-output analysis for energy metabolism system in the Province of Guangdong, China, In: Journal of Cleaner Production196pp. 747-762 IOP Publishing

The development of human society is inseparable from energy. The exploration of urban energy metabolism plays an essential role in improving sustainable development. Combing input-output analysis with ecological network analysis help academics to shed light into the complicated system interactions and interior energy flows. In this study, using Guangdong as a case study, the Energy Ecological Network model is developed to account for the intensity of the embodied energy consumption using monetary input-output tables from 2000, 2002, 2005, 2007, 2010, and 2012. Sectors and energy flows are treated as nodes and paths to compile the corresponding physical input-output tables, which can facilitate a more comprehensive and balanced understanding of urban energy consumption by integrating various accounting perspectives. In detail, network control analysis is extended to reveal inter relationships and relative contribution rate of each sector. Network utility analysis gives an overall consideration of the dynamic changes in energy metabolism relations from multiple perspective. Furthermore, the modified robustness method penetrates into how each sector affects the stability of the system. The results show that the energy metabolic level in Guangdong is relatively low and indirect flows are the key to improving the system efficiency. The advanced manufacturing (AM) sector relied on other sectors in energy trade and have limited reciprocal relationships in the study period. Therefore, it is urgent to adjust the external structure and internal circulation of AM sector. The comprehensive dynamic analysis will give a scientific support to guide the development of energy reform in an attempt to promoting healthier development of energy metabolism system.

Boyue Zheng, Guohe Huang, Lirong Liu, Mengyu Zhai, Yuru Guan (2019)Metabolism of urban wastewater: Ecological network analysis for Guangdong Province, China, In: Journal of Cleaner Production217pp. 510-519 Elsevier

Wastewater discharge is a burden on environmentally sustainable development, especially in the water-deficient area. Existing Studies on wastewater discharge is not comprehensive for lacking analysis of mutual flow and necessary components. In this study, a wastewater metabolism input-output model is developed to achieve sustainable development through a novel perspective to depict the industrial wastewater flow among sectors. Since chemical oxygen demand and ammonia nitrogen are indicators for studying the degree of wastewater pollution, this paper also considers their wastewater to make the research synthetic and systematic. A case study of Guangdong Province, China, is conducted to further illustrate the potential benefits of the model in investigation of the sectors interactions. The results show that the wastewater discharge of Guangdong Province is considerable, with industrial wastewater, chemical oxygen demand wastewater and ammonia-nitrogen wastewater being 7.53 billion tons, 852 thousand tons and 69 thousand tons respectively. Some typical sectors have been distinguished based on ecological network analysis and input-output analysis for mitigating wastewater discharge, such as electronic equipment manufacture, chemical materials and paper manufacture, and tertiary industry. The implementation of the “Replace Subsidies with Rewards” policy is conducive to the discharge reduction of the system.

Kaiqiang Zhang, Leng Tian, Lirong Liu (2018)A new analysis of pressure dependence of the equilibrium interfacial tensions of different light crude oil–CO2 systems, In: International Journal of Heat and Mass Transfer121pp. 503-513 Elsevier

In this paper, the equilibrium two-phase compositions are predicted and analyzed to elucidate the pressure dependence of the equilibrium interfacial tensions (IFTs) of three different light crude oil–CO2 systems. First, three series of the dynamic IFT tests for a dead light crude oil–pure CO2 system, a live light crude oil–pure CO2 system, and a dead light crude oil–impure CO2 system at different equilibrium pressures from the literature are used. Second, the modified Peng–Robinson equation of state (PR-EOS) is tuned by using measured pressure–volume–temperature (PVT) data to predict the equilibrium two-phase compositions of the three light crude oil–CO2 systems. Such tuned PR-EOS together with the parachor model is applied to predict the equilibrium IFTs, which are compared with and validated by the measured IFT data. Third, the pressure dependence of the equilibrium IFTs, the initial oil and gas composition effects, and the initial gas fraction effect are examined. The density difference between the light crude oil and gas phase is found to be a key factor in the parachor model for the IFT predictions. The equilibrium IFT vs. pressure curve is found to have three different pressure ranges, which correspond well to those for the density difference. Moreover, the initial oil and gas compositions affect the equilibrium two-phase compositions and IFTs to different extents. The live light crude oil–pure CO2 equilibrium IFT is reduced with an increased initial gas fraction. For the dead light crude oil–pure/impure CO2 system, the miscibility with zero IFT can be achieved only if the initial gas phase has more than 0.70 mol fraction. Otherwise, it is the complete gas dissolution into the light crude oil that leads to zero IFT.

Xinli Xu, Guohe Huang, Lirong Liu, Yuru Guan, Mengyu Zhai, Yongping Li (2019)Revealing dynamic impacts of socioeconomic factors on air pollution changes in Guangdong Province, China, In: Science of the Total Environment699134178 Elsevier

The rapid development of cities leads to the frequent occurrence of air pollution incidents, which seriously hinders urban sustainability. This study develops a dynamic regional air pollution analysis (DRA) model to explore the mechanism of air pollutant emission changes. Specifically, the emissions differences among various sectors are distinguished by multi-angle accounting (MAA) method, and sectors' evolutionary trajectories are described by sector evolution analysis (SEA). Through combining emission deconstruction analysis (EDA) and structural decomposition analysis (SDA), key emission patterns and decisive socioeconomic factors are identified. The empirical results indicate that different sectors play different roles in the urban emission system and differentiated regulation policies should be formulated according to their characteristics. Changes of demand and supply patterns can result in the fluctuation in regional air pollutant emissions. Exports and worker's reward are the most significant contributors to air pollution on demand and supply sides, accounting for more than 54.3% and 44.0% of total emissions, respectively. The final demand level and the primary input level are the two biggest drivers of the emission increase, while emission intensity is the most crucial factor that offsets the emission growth. Also, there are significant differences in demand and supply structure. The contribution of primary input structure to emission reduction was more significant than that of final demand structure, which contributed 14.6% in 2015. The findings in this study will provide reliable information for developing more comprehensive and effective mitigation policies

Chengyu He, Guohe Huang, Lirong Liu, Yongping Li, Xiaoyue Zhang, Xinli Xu (2020)Multi-dimensional diagnosis model for the sustainable development of regions facing water scarcity problem: A case study for Guangdong, China, In: Science of The Total Environment734139394 Elsevier

Freshwater consumption and wastewater discharge of economic activities have caused water scarcity problem in many regions. This study aims to develop a multi-dimensional diagnosis model (MDDM) to provide new insights for the sustainable development of regions which face water scarcity problem. In detail, the sectorial blue water, grey water and total water consumptions are assessed to reveal the direct effects of economic activities on water quantity and water quality. Then, hypothetical extraction method is integrated into input-output model and ecological network analysis to quantify the system-based effects of sectors in three dimensions: economy, water and metabolism. A case study of Guangdong province, China is conducted to illustrate the availability of the developed model. We found that the multi-dimensional performances of Guangdong's socioeconomic system are dominated by a few sectors. Wastewater, especially that discharged from the primary industry, is the main reason for the local water scarcity. Specifically, the unique role that every sector plays in the socioeconomic system is quantitatively revealed by MDDM, which could guide the relevant policy development at sectorial level.

Kaiqiang Zhang, Na Jia, Songyan Li, Lirong Liu (2018)Nanoscale-extended correlation to calculate gas solvent minimum miscibility pressures in tight oil reservoirs, In: Journal of Petroleum Science and Engineering171pp. 1455-1465 Elsevier

In this paper, a novel nanoscale-extended correlation is developed to calculate the minimum miscibility pressures (MMPs) for a wide range of dead and live tight oil−gas solvent systems in bulk phase and nanopores. First, experimentally, the slim-tube and coreflood tests as well as the vanishing interfacial tension (VIT) technique are conducted to measure the MMPs of three oil‒gas systems. Second, the newly-developed correlation is proposed as a function of the reservoir temperature, molecular weight of , mole fraction ratios of volatile components to intermediate components in oil and gas samples, and pore radius. Third, theoretically, the new correlation is analyzed on a basis of an oil‒gas MMP database from this study and literature that covers 101 oil‒gas MMP data for fifteen oil and thirteen gas samples at different reservoir temperatures in bulk phase and nanopores. A total of 40 commonly-used existing correlations are analyzed and reviewed. Compared to the seven existing correlations, the new correlation is found to provide the most accurate MMPs with an overall percentage average absolute deviation (AAD%) of 5.72% and maximum absolute deviation (MAD%) of 12.96% for different dead and live oil‒pure CO2 systems in bulk phase. Moreover, for the different oil‒pure and impure gas solvent systems, the new correlation leads to the best calculation accuracy of the MMPs with an overall AAD% of 4.70% and MAD% of 15.81% in comparison with the four existing correlations. More importantly, the new correlation is found to calculate the MMPs of different dead and live oil‒pure and impure gas solvent systems in nanopores in an accurate, efficient, and physical correct manner. The overall AAD% and MAD% in terms of the MMP calculations in nanopores from the new correlation are determined to be 6.91% and 13.66%, respectively.

Kaiqiang Zhang, Na Jia, Lirong Liu (2019)Generalized critical shifts of confined fluids in nanopores with adsorptions, In: Chemical Engineering Journal372pp. 809-814 Elsevier

Confined fluids undergo substantial changes in terms of their physicochemical properties when the pore radius reduces to the nanometric scale and be comparable to the molecular size. Adsorptions, which are the corresponding changes in the concentration of a given fluid at the interface compared with the other contacting phase, strongly affect the vapour-liquid equilibrium (VLE), especially in nanopores. No published literature so far has been found to study the critical shifts of confined fluids with adsorptions in nanopores. In this study, first, the van der Waals (vdW) and Soave-Redlich-Kwong (SRK) equations of state (EOSs) are extended to calculate the VLE of confined fluids in nanopores. Second, a new empirical correlation is developed to calculate the fluid adsorption thickness in nanopores. Finally, two generalized analytical formulations, on a basis of the modified vdW and SRK EOSs, are initially proposed to calculate the shifts of critical temperatures and pressures by considering the fluid adsorptions in nanopores. All the extended EOSs, new adsorption correlation, and two generalized formulations have been validated to be accurate by comparing with the experimental or literature data. Overall, the critical properties of the confined fluids are found to shift more with adsorptions in nanopores. Moreover, the compressibility factors of the confined Lennard–Jones fluids are proven to be universal and independent of the pore radius effect.

Xinli Xu, Guohe Huang, Lirong Liu, Jizhe Li, Mengyu Zhai (2019)A mitigation simulation method for urban NOx emissions based on input-output analysis, In: Journal of Cleaner Production249119338 Elsevier

With the frequent occurrence of global warming, acid rain, and photochemical smog, nitrogen oxide (NOx) pollution has become an increasingly serious global problem. It is essential to establish efficient approaches for seeking reasonable and practical mitigation pathways. In this paper, a NOx mitigation simulation (NMS) model is developed to facilitate the development of mitigation policies. Through constructing the NOx metabolic network, all sectors are classified according to their interactions. With production-side and consumption-side mitigation strategies adopted for different categories respectively, the changes of sectoral and system-wide indirect emissions are accounted for under the framework of urban metabolism. The results of the case study for Guangdong Province, China, illustrate that the mitigation strategies aimed at the specific sectors of the economy might not be as practical as expected. Both the type of mitigation strategies and the sector category it interferes with have a decisive influence on reduction performance. In Guangdong Province, regulating electricity, heat power generation and smelting, pressing of metals can achieve substantial reduction performance through production-based ways, and supervising the sectors with weak control and strong dependence (e.g., Construction and Other social services) is the most effective measure on the consumption side. The comprehensive mitigation strategies made from production and consumption perspectives are capable of acquiring the most efficient reduction performance. Considering cities as an ecosystem, the mitigation simulation framework established in this study has the potential to assess and formulate reduction policies of NOx emissions.

Yuanna Wu, Zezhong Li, Lirong Liu (2013)Study on Objective Integrated Control of New Energy Power Projects based on Reliability Theory, In: TELKOMNIKA Indonesian Journal of Electrical Engineering11(8)pp. 4539-4547 Institute of Advanced Engineering and Science

Based on the research status of objective control theory of new energy power projects, analysed the system components of power projects, proposed the subsystem reliability control theory directed at four objectives, gave reliability control standards and calculation methods of four objectives, obtained the objective integrated method of subsystem reliability, used disjoint minimal path sets method to deal with the minimal path sets in the project construction process, proposed system reliability control theory of new energy power projects, then combined the known reliability control standards to assess project reliability, finally established objective integrated control model of new energy power projects based on reliability theory. Finally an simple example proves that the proposed objective integrated control model is simple and practical

Gordon Huang, LIRONG LIU, Xiaoyue Zhang, Jinbo Zhang, Yupeng Fu, Bin Luo, Mengna Li, Xiaogui Zheng (2019)Canadian Energy System Management under Climate Change Conditions, In: 2019 International Conference on Computing, Electronics & Communications Engineering (iCCECE)pp. 26-31 IEEE

Energy activities, as main cause of environmental and climate change issues, become the main concern of Canada for past decades. Robust and sustainable energy systems are essential to the prosperity of the regional, national and global economy. Energy systems consist of many components that are closely related to socio-economic development and resources conservation with multiple criteria and objectives. These components may be interrelated to each other and may present uncertain and dynamic features, associated with spatial heterogeneity, implying issues of system reliability and economic/environmental effects. Effective systems planning and policy-making support are desired for the long-term energy-environment management. In this study, eight representative regions in Canada with typical energy-related issues are identified and analyzed. A set of mathematical algorithms are integrated into the regional energy model framework to tackled uncertainties. Tradeoffs between environmental goals, economic benefits, and energy development in these regions can be reflected. Different scenarios involving greenhouse gas emission goals and renewable utilizations are analyzed, which can provide a sound basis for local governments' policy and strategy development in the future.

Yun-na Wu, Jian Chen, Li-rong Liu (2011)Construction of China's smart grid information system analysis, In: Renewable and Sustainable Energy Reviews15(9)pp. 4236-4241 Elsevier

The start of the smart grid program will drive significant changes of grid operation, management, customer service and social energy use patterns. Informatization as the Smart Grid “four modernizations” breakthrough feature, its importance is distinguished. The important feature, trends, construction direction of smart grid informatization will be the power companies and the IT industry issues of common concern. This article outline the construction contents of smart grid and analysis the informatization technology position in the smart grid and demand for informatization of smart grid construction. And on this basis, analyze the smart grid informatization construction system, and shows the contents of informatization construction from three different dimensionalities: the information hierarchy, power industry chain and business type. Finally, describe the contents of informatization construction and business application from five dimensionalities: data collection layer, data transmission layer, data analysis layer, information integration layer, and information showing layer.

Mengyu Zhai, Guohe Huang, Lirong Liu, Xin Zhang (2019)Ecological network analysis of an energy metabolism system based on input-output tables: Model development and case study for Guangdong, In: Journal of Cleaner Production227pp. 434-446 Elsevier

Rapid urbanization results in energy shortage and unreasonable energy metabolism structure. The goal of this research is to take Guangdong, China as a special case study to illustrate the influence of energy classification differences on the energy metabolism system. To do so, we introduced the concept of “urban metabolism”, and treated sectors and energy flows as nodes and paths in a network model. We used the input output analysis to compile the physical input output table through the embodied energy element intensity. Building on this, we used ecological network analysis to quantify the urban metabolic processes and energy metabolism levels within the urban system. In addition, the alternative indicators are first introduced to explore the best alternative energy in various sectors to avoid a short-term energy crisis. In this paper, different energy groups are considered on the energy metabolism system, including all energy, primary energy, secondary energy and six specific energy, which will fill the research gap about the influence of energy classification on urban energy metabolism. It is found that the energy metabolism of Guangdong is now in the state of sub-health. The energy metabolism hierarchy atlas shows that the pulling force is hardly affected by the energy classification but the driving force is very sensitive, which further illustrate that producers can choose different energy according to their production structure. Facing the shortage of energy supply, the secondary energy with the highest substitutability of all energy value is the better alternative energy for advanced manufacturing sector (containing twelve industries such as Manufacture of transportation equipment and Manufacture of metal products). More specifically, the nonrenewable properties of primary energy make it particularly important to find the corresponding alternative energy. Heat is the best alternative energy for crude oil, while electricity is irreplaceable. It is expected that the results will provide scientific support to guide the reform of urban energy metabolic system in an attempt to coordinate the energy development strategy, improve the energy consumption structure and maintain energy security and stability.

Yuru Guan, Guohe Huang, Lirong Liu, Mengyu Zhai, Xinli Xu (2019)Measurement of air-pollution inequality through a three-perspective accounting model, In: Science of The Total Environment696133937 Elsevier

China is suffering from serious air pollution. Regional air quality varies significantly due to intensive inter-provincial trades, diversified resource endowments and complicated economic structures. This study breaks the limitations of measuring environmental inequality only from a single perspective and establishes a three-perspective atmospheric pollutant equivalents accounting model (or APE accounting model) for air-pollution inequality assessment under environmentally-extend multi-regional input-output framework. From three perspectives of local production (i.e. production-based), final demand (i.e. consumption-based) and primary supply (i.e. income-based), APE emissions, APE transfers and environmental Gini coefficient are investigated to exam emission responsibilities of various impact factors, evaluate the impacts of inter-provincial trades on pollutants transfers, and characterize regional emission inequalities at both provincial and sectoral levels. The results indicate that local emitters are merely parts of contributors to air pollution. Direct emitters like Hebei Province, primary suppliers like Inner Mongolia and final consumers like Shandong Province induce large amounts of air pollutants as embedded within various economic activities. Because of unequal supply-demand levels and complex exchange mechanisms, three-perspective APE emissions are significantly heterogeneous, especially in mining, construction, energy and material-transformation sectors. Particularly, inequality of the mining sector in embodied emissions has the highest environmental Gini coefficient (0.881). This model provides a framework to assess regional environmental inequality and its findings provide scientific bases for the formulation of desired regional air pollution control policies.

Global warming has received more and more attention in recent years for its inevitable influence on population, species, soil, ocean, water and so on. It is essential to investigate the urban metabolism of carbon emissions which is a main cause of global warming and most of it occurs in the process of production and living in urban areas. In this paper, a carbon emission metabolic network is established to explore the emission reduction strategies by modeling carbon dioxide flows and identifying the mutual relationships based on the input-output analysis. Specifically, Eff-Lorenz curve derived from the painting of Lorenz curve is developed to compare the efficiency of carbon emissions from different sectors. The newly developed method has been applied to Guangdong province to demonstrate its availability and benefit. It is revealed that carbon emissions mainly concentrated in the secondary and tertiary industries with electric power generation, manufacturing industry, domestic consumption and transportation ranking at the top. The competition relationship reveals good interactions in terms of emission reduction while a mutualism relationship provides effective pathways to mitigate carbon emissions between pairwise sectors simultaneously. In Guangdong province, upgrading the clean combustion technology in electric power generation and energy extraction sectors would drive other sectors to cut emissions and adjusting the production structure of the construction sector also contribute to achieve this goal. The results are expected to provide corresponding and holistic reference for decision makers to develop the mitigation policies.

Lirong Liu, Guohe Huang, Brian Baetz, Kaiqiang Zhang (2018)Environmentally-extended input-output simulation for analyzing production-based and consumption-based industrial greenhouse gas mitigation policies, In: Applied Energy232pp. 69-78 Applied Energy

Industrial GHG mitigation policies are prevalent across the world to realize global greenhouse gas (GHG) emissions targets. It is essential to simulate the impacts of different policies on various industries in the socio-economic system to find out the most effective emission reduction pathways. In this study, an Environmentally-Extended Input-Output Simulation (EEIOS) model is developed to facilitate integrated GHG mitigation policy development for multiple industries from both production and consumption sides. In addition, a Production-Consumption Rate is proposed to reflect the differences between Production-Based Policies (PBP) and Consumption-Based Policies (CBP) for a certain industry, which further supports the optimized and systematic emission reduction strategy development. A special case study of the Province in Saskatchewan, Canada, is conducted to illustrate the applicability and superiority of the Environmentally-Extended Input-Output Simulation model. It is found that Production-Based Policies applied to primary industries will lead to larger GHG reductions, and that Consumption-Based Policies should be applied to industries that are located at the end of industrial chains. The results provide a solid scientific basis for supporting industrial greenhouse gas mitigation policy development for each industry and identifying the optimized emission reduction pathways for the entire socio-economic system.

Xinli Xu, Guohe Huang, Lirong Liu, Chengyu He (2019)A factorial environment-oriented input-output model for diagnosing urban air pollution, In: Journal of Cleaner Production237117731 Journal of Cleaner Production

The excessive emissions of various air pollutants seriously hinder the sustainability of cities. It is imperative to conduct a thorough diagnose of urban emission systems. The objective of this study is to develop a factorial environment-oriented input-output (FEIO) model to reveal the urban emission system's structural characteristics and possible internal interactions. Through constructing urban emissions networks regarding multiple air pollutants, the crucial transfer sectors and their relevant transactions are identified. Based on the results of identification, factorial analysis (FA) is further introduced to explore the effects of designed factors and their combinations. The results of the case study for Guangdong Province, China demonstrate that the urban emission system differs from the natural ecosystem because of its complex structure. The impact of various air pollutants on the urban ecosystem is different from what they are expected, both the emitting sectors and their energy consumption structures are decisive. In Guangdong province, Manufacture of Metal and Non-metallic Mineral Products (MMN), Electric Power (EP), Electronic and Telecommunications Equipment (ETE) and Chemical Products (CP) are identified as transfer centers in the emission network. The contribution of air pollution derived from coal consumption is more than 48.30%. Both in 2012 and 2015, the contribution of interactions exceeded 17.46%. The VOCs emissions emitted by MMN and SO2 emissions emitted by EP have the greatest impact on the regional ecosystem. These findings can provide reliable information for ensuring regional air environmental protection targets.

Mengyu Zhai, Guohe Huang, Lirong Liu, Boyue Zheng, Yuru Guan (2018)Network analysis of different types of food flows: Establishing the interaction between food flows and economic flows, In: Resources, Conservation and Recycling143pp. 143-153 Elsevier

Food security is performed as an important issue, which is directly related to human survival, social progress and environmental protection. The aim of this paper is to establish a holistic and new food network model that is capable of exploring the nature of food flows in response to the regulation of sectoral activities from a practical perspective. A case study for Guangdong Province, China is conducted to illustrate the influence of different food types on urban food system by combining Input Output Analysis and Ecological Network Analysis. In detail, the applicability of these methods is first extended to food element. The study on complex food system involving ecology, society, and the environment is the first time to use network analysis to quantify the urban metabolic processes. In addition, the Value intensity of flow (VIF) is first introduced to re-establish the relationship between food flows and economic flows. The results show that the indirect food flows have a huge impact on food system. Food processing (FO) and Accommodation and catering services (AC) are the most important sectors to promote and support the development of other sectors. The food type has great impacts on pulling force and the level of commercial value, while it does not affect the flows of commercial value. As a raw material in many industries, sugarcane affects the metabolic relationships between sectors

Kaiqiang Zhang, LIRONG LIU, Songyan Li, Na Jia (2020)Thermodynamic Parameters for Quantitative Miscibility Interpretations from the Bulk to Nanometer Scale, In: Industrial & Engineering Chemistry Research59(22)pp. 10634-10650

Carbon capture and storage (CCS) is currently a main way to reduce anthropogenic CO2 emissions. However, the supplies of ideal reservoirs for the geological CO2 storages are substantially less than the demands if the CO2 storage is treated as a usual method to reduce the anthropogenic CO2 emissions and implemented worldwide. On the other hand, the tight/shale formations with micro/nanopores are extensively distributed, which are usually fractured by providing the outer pressures (e.g., injecting CO2) or after the tight/shale oil/gas productions. Hence, it is necessary to study the potential CO2 storages in the fractured tight formations. In this paper, thermodynamic phase behaviour for the CO2 storage process in the fractured tight formations (i.e., nanoproes) with adsorptions are studied. More specifically, first, an analytical equation of state (EOS) is modified and applied to calculate the thermodynamic phase behaviour of confined pure/mixing fluids in nanopores considering the effects of pore radius and molecule‒molecule (m‒m) interactions. Second, a new empirical correlation for predicting the adsorption thickness in nanopores is initially developed. The modified EOS coupled with the new adsorption thickness correlation and the fracture geometry equation is used to calculate the phase behaviour of confined pure and mixing CO2 streams in fractured nanopores with adsorptions. The phase behaviour, which include the pressure‒volume (P‒V) diagrams, pressure‒temperature (P‒T) diagrams, and critical properties, of 12 pure substances of CO2, N2, and alkanes of C1‒10 and 12 CO2-dominated binary and ternary mixtures are specifically studied. A new empirical correlation for the adsorption thickness is developed, which is coupled with a modified van der Waals EOS (vdW-EOS) and the fracture geometry equation to calculate the phase behaviour of confined pure and mixing CO2 streams in fractured nanopores with adsorptions. The calculated pressures for all cases in nanopores with and without the adsorptions and fractures are reduced with the system volume increases while they are increased by increasing the system temperature with constant compositions, which are always larger than those in bulk phase at small volumes but in good agreement at large volumes. In comparison with the N2 or C1‒10, the pure CO2 is more easily transited to be a liquid or supercritical phase. Moreover, any additions of N2 or C1‒10 into the pure CO2 increase the vapour/bubble pressures to different extent, especially in nanopores. In the P‒V diagrams of pure and mixing CO2 streams, the pressures are more sensitive to the volume change in pure gas phase but the liquid‒gas or liquid‒liquid phase are inert to the volume expansions. The pressures in the P‒T diagrams are monotonically increased with the temperature in bulk phase and nanopores. The pressure-transition pressures of the C1‒10 become more sensitive to the temperature with the carbon number increase. In comparison with the N2 or C1‒10, the pure CO2 is more easily transited to be a liquid or supercritical phase. Any additions of N2 or C1‒10 into the pure CO2 lead the system pressures to increase more with the temperature to different extent, especially in nanopores. Also, the pressures in nanopores become even higher than those in bulk phase for the CO2-dominated binary and/or ternary mixtures. The critical properties with the adsorptions and fractures are decreased with the pore radius reduction to some certain level, which agree well with the results without the adsorptions or fractures, and reversed to increase afterwards. The bottom pore radius for the coincidences of the critical properties with and without adsorptions and fractures vary for different substances. The critical properties, in comparison with the pure CO2 case, are substantially decreased by adding N2 or C1‒10, wherein the N2 exerts the strongest effect while the effects of the alkanes are weakened with the carbon number increase. Furthermore, the critical properties of the binary and ternary mixtures with and without adsorptions and fractures are similar at rp = 0.4‒1000 nm. Finally, for CO2 storage projects in the deep tight formations, three optimum strategies are obtained from this study and listed as follows: lager pore radii (by natural or manmade fractures), purified CO2 streams, and low temperatures. At the current stage that the experimental methods are incapable of fully exploring the nanoscale phase behaviour, this study is critically important because the CO2 storage is the key part to mitigate the greenhouse gas emissions and control the climate change to a manage and meanwhile, its applications in the tight/shale formations with micro/nanopores are inevitable in the near future.

Xiaoyue Zhang, Guohe Huang, E Hussein, LIRONG LIU A Universally Applicable Approach for Small Modular Reactors Site Selection
Mandula Naren, Lirong Liu, Long Zheng, Yun Na Wu (2020)The Schedule Control of Nuclear Power Construction Phase of Project Approval and Administrative Licensing, In: Applied Mechanics and Materials291pp. 2995-3003 Trans Tech Publications

As a clean and economic power, nuclear power has become an important part in China’s power structure. Nuclear power plant project has the characteristics of large investment and long period, thus requiring a strict schedule control. This paper deeply studied the work contents of China’s nuclear power project approval and administrative license, selectively analyzed the required supporting documents for this phase, and simplified the work into several phases. According to the feature of each phase, we created the “laddering” model; controlled the schedule in three respects, including: nuclear power connected to grid related supportive documents, nuclear power construction related supportive documents, and the nuclear power security and environmental protection related supportive documents. By realizing the schedule control of the phase in nuclear power project in this paper, we hope to further enhance the level of China’s nuclear power construction project managements, ensure the economic and security of nuclear power projects and better promoted nuclear power projects.

Mengyu Zhai, Guohe Huang, Hongzhi Liu, Lirong Liu, Chengyu He, Zhengping Liu (2019)Three-perspective energy-carbon nexus analysis for developing China's policies of CO2-emission mitigation, In: Science of The Total Environment705135857 Wiley

Energy usage and CO2 emission have intimate and inseparable linkages. The growth of energy usage causes an increase in CO2 emissions, which will in turn constrain the related energy policies and challenge the energy-system stability. It is essential to quantify China's CO2 emission inventories embodied in production-driven, demand-driven and supply-driven chains considering different energy types. A Three-Perspective Energy-Carbon Nexus model is developed to facilitate comprehensive CO2 emission-reduction analysis in China. The model incorporates environmental input-output analysis and ecological network analysis within a general framework to clarify the relationships among provinces in terms of the production-based, consumption-based and income-based accountings. A new indicator, indirect emission dominant factor, is for the first time examined to evaluate the dominant capabilities of indirect emissions. It is discovered that the emissions triggered by the demand-side are not sensitive to energy types. Furthermore, the changes of integral flow control intensity in each province are insignificant from consumption-based and income-based perspectives. Final demand contributes 80% of consumption-based emissions and gross value-added creation leads to a total of 82% income-based CO2 emissions in China in 2012. When controlling emissions from multiple perspectives, traditional methods may not be effective since they do not consider the forms of emissions; some methods (e.g., product allocation) are not suitable for suppressing indirect emissions. Moreover, the prosperity of developed regions (e.g. Guangdong) highly rely on support from underdeveloped regions (e.g. Inner Mongolia). Some underdeveloped provinces are receptors of CO2, while the developed ones are emitting CO2 to the system without assuming their emission-reduction responsibilities. In addition, secondary energy consumptions in developed regions are conducive in increasing their emission contributions to the system. In this research, an innovative perspective is initiated to disclose the energy-carbon interconnections across Chinese provinces. The obtained findings could help support the formulation of China's CO2 emission-reduction policies.

Yuru Guan, Guohe Huang, Lirong Liu, Charley Z. Huang, Mengyu Zhai (2018)Ecological network analysis for an industrial solid waste metabolism system, In: Environmental Pollution244pp. 279-287 Elsevier

Faced with an increasing amount of industrial solid waste (ISW) in the process of rapid industrialization, it is indispensable to carry out ISW metabolism study to realize source and waste reduction. In this study, a new composite waste input-output (WIO) model is developed to examine ISW production and production relationships among different sectors. In particular, the extended methods of network control analysis and network utility analysis are used in the ecological network analysis under two ISW scenarios (i.e. common industrial solid waste (CISW) and hazardous waste (HW) scenarios). Furthermore, comprehensive utilization analysis is first developed to evaluate the ISW utilization level and to guide the planning of sectors with large proportion of ISW production. A case study of Guangdong, China shows that indirect flow analysis can be used to understand the internal ISW metabolism structure. The mining sectors produce a large amount of direct ISW and perform a low level of comprehensive utilization, but they have mutualism relationships with other sectors. The energy transformation (EH) sector in the CISW system has high direct generation intensity and plays as a main controller. The situation of paper manufacturing (MP) sector in HW system is similar to that of EH. Therefore, it is expected that the results of this study will provide scientific foundations for these sectors to formulate future ISW reduction policies.

Kaiqiang Zhang, Songyan Li, Lirong Liu (2020)Optimized foam-assisted CO2 enhanced oil recovery technology in tight oil reservoirs, In: Fuel267117099 Elsevier

In this paper, foam-assisted CO2 EOR and anti-gas channelling technology are investigated and optimized to enhance tight oil recovery. A series of laboratory experiments, including pressure−volume−temperature, foam generation and evaluation, and coreflood tests, and phase behaviour theoretical mathematical models are performed to evaluate foam agent, analyze anti-gas channelling mechanisms and influential factors, and optimize foam-assisted CO2 EOR technique. The specific CO2 bulk fluid behaviour and phase behaviour in wellbore are determined through experimental and theoretical models. Two distinct stages are found to be divided prior to and after the CO2 gas breakthrough. Most oil productions, which is in the range of 28–40%, occur prior to the gas breakthrough, whereas only additional 5–8% oil is produced after the gas breakthrough. A higher injection rate and/or permeability ratio result in an earlier gas breakthrough and causes less oil to be produced before gas breakthrough while the oil recovery factor slightly increases after the breakthrough by increasing injection rate. Gas diffusion in water-saturated core reach equilibrium faster than that in the oil-saturated core. An overall evaluation parameter is developed to select foam agent. The optimized static condition for the selected foam agent here is approximately 9 MPa at low temperatures while dynamic performance is improved at a higher gas but lower liquid injection rate. The simultaneous water-alternating-gas injection scheme in subsequent of an initial gas injection with liquid−gas ratio of 1:1 performs better than the water-alternating-gas scheme, which is proven to be effective for the core samples with fracture width of 82.67 μm. Finally, the oilfield surface foaming operational system is designed to upscale laboratory research to practical applications with specific operating setup and procedures, which has been applied in the target oil reservoir and performs well as expected.

Boyue Zheng, Guohe Huang, Lirong Liu, Yuru Guan, Mengyu Zhai (2019)Dynamic wastewater-induced research based on input-output analysis for Guangdong Province, China, In: Environmental Pollution256113502 Elsevier

Large amounts of wastewater discharge have emerged as a burden in the process of industrialization and urbanization. In this study, a dynamic wastewater-induced input-output model is developed to systematically analyze the related situation. The developed model is applied to Guangdong Province, China to analyze its prominent characteristics from 2002 to 2015. Combining input-output analysis, ecological network analysis and structural decomposition analysis, the developed model reveals issues of direct and indirect discharges, relationships among various discharges, and driving forces of wastewater discharges. It is uncovered that Primary Manufacturing and Advanced Manufacturing dominate the system because of significant temporal and spatial variations in wastewater discharge. In addition, Manufacturing of paper, computer and machinery and Services are the key industries responsible for large amounts of wastewater discharge and unhealthy source-discharge relationships. The largest wastewater discharge occurred in 2005 and indirect wastewater discharge is the main form. Furthermore, final demand is found to be the biggest driving force of wastewater discharge. Finally, a three-phase policy implementation system implemented in stages proposes solutions to wastewater problems.

Kaiqiang Zhang, Na Jia, Songyan Li, Lirong Liu (2019)Quantification and Evaluation of Thermodynamic Miscibility in Nanoconfined Space, In: Industrial & Engineering Chemistry Research58(11)pp. 4609-4624 American Chemical Society

In this paper, thermodynamic miscibility in nanoconfined spaces is quantified and evaluated. First, an analytical generalized equation of state (EOS) is developed by considering the effects of pore radius, molecule–molecule interaction, and molecule–wall interaction at nanometer scale, on the basis of which four extended cubic EOS are proposed. Second, the analytical formulations of the confined fluid free energy of mixing and solubility parameter at nanometer scale are developed thermodynamically. Third, the free energy of mixing and solubility parameter are calculated under different conditions, by means of which the conditions and characteristics of the fluid miscibility at nanometer scale are specifically studied. Finally, two important factors, the temperature and molecule–wall (m–w) interaction, are specifically studied to evaluate and compare their effects on miscibility. The fluid miscibility benefits from the reduction of the pore radius, while the m–w interaction is detrimental to the development of miscibility. Moreover, the molecular size of the single largest molecule in the mixture along with the wall-effect region radius is determined to be the bottom limit of the pore radius, above which fluid miscibility can be achieved and improved by reducing the pore radius. It is found that the solubility parameter is a better quantitative indicator of fluid miscibility; the calculated results from the extended van der Waals, Soave–Redlich–Kwong, and Peng–Robinson EOS are better than those from the extended Redlich–Kwong EOS. Furthermore, a more fluid miscible state is found to be achieved by reducing the temperature and wall-effect region radius. The extent of the effect of temperature on the fluid miscibility of different mixtures can be different. More specifically, the so-called lean gas (i.e., N2, CH4, and CO2)-induced miscibility through the vaporizing process is found to be affected by the temperature to a larger extent in comparison with the rich gas (i.e., C2H6, C3H8, and i- and n-C4H10)-induced miscibility through the condensing–vaporizing process.

Kaiqiang Zhang, Na Jia, Songyan Li, Lirong Liu (2018)How surfactant-decorated nanoparticles contribute to thermodynamic miscibility, In: Nanotechnology29(47)475701 IOP Publishing

In this study, mineral oil–water fluid miscibility without and with the addition of surfactant-decorated nanoparticles is experimentally and theoretically studied. First, three series of interfacial tension (IFT) tests are conducted using a spinning drop tensiometer (SDT) with the addition of hexadecyltrimethylammonium bromide (CTAB) surfactant-decorated SiO2 nanoparticles at different concentrations. Second, a new comprehensive thermodynamic model is developed to describe the fluid miscibility without and with the addition of these surfactant-decorated nanoparticles, which is also applied theoretically to reveal how the surfactant-decorated nanoparticles contribute to the thermodynamic miscibility state. The thermodynamic model developed is proven to be accurate and physically meaningful by comparing its calculated free energy of mixing with the experimental results and examples from the literature. A series of optimum conditions for the improvement of fluid miscibility by the addition of such surfactant-decorated nanoparticles are determined: a lower temperature, a higher pressure, more wetting conditions, a smaller nanoparticle radius (r NP < 40 nm), a larger surfactant concentration, and a nanoparticle concentration in the range of 0.5–0.6 wt.%. It should be noted that a higher nanoparticle concentration is required with the addition of more CTAB surfactants in order to reach the most miscible state. Moreover, the effect of surfactant concentration on the miscibility development is found to be independent of the nanoparticle radius, whereas the optimum nanoparticle concentration is reduced with increasing particle size.

Xin Zhang, Guohe Huang, Lirong Liu, Mengyu Zhai, Jizhe Li (2018)Ecological and economic analyses of the forest metabolism system: A case study of Guangdong Province, China, In: Ecological Indicators95pp. 131-140 Elsevier

Integrating forest resources into the socio-economic system correctly and reasonably is of vital importance to tackle the increasingly scarce forest resources. In this paper, forest resource input-output model and forest resource metabolism network model are established to provide new insights into the relationships among the systems, industries and sectors related to forest resources. A promising indicator named exploitation index is developed to reveal the weaker sectors in the ecological relations, which will further help to provide better corrective actions and integrated strategic measures. Guangdong is taken as an example to verify the availability of the model and solve the problem. The results show that the primary manufacturing consumes more direct timber, while advanced manufacturing and the service sector utilize timber indirectly. In addition, Guangdong forest metabolism system shows a negative correlation and the whole network does not achieve the mutualism state, leading to competition relationships between pairwise sectors that should not appear, such as Forestry sector and Papermaking and Paper Products sector. These results provide the corresponding reference for helping the decision makers to allocate forest resources and coordinate ecological and economic development.

Mengyu Zhai, Guohe Huang, Lirong Liu, Boyue Zheng, Yuru Guan (2019)Inter-regional carbon flows embodied in electricity transmission: network simulation for energy-carbon nexus, In: Renewable and Sustainable Energy Reviews118109511 Elsevier

Energy use and CO2 emissions are inextricably linked. Energy utilization leads to an increase in CO2 emissions, which will in turn limit the formulation of energy policies and stability of energy systems. A provincial-scale Energy-Carbon Nexus Model is established to shed insight into the complicated system interactions among provinces. Specifically, different power generation types are considered to quantify the inter-provincial transfers of CO2 embodied in electricity transmission through the Multiregional Input-Output Analysis. Ecological Network Analysis is used to describe the integral mutual relationships between provinces and distinguish the control intensity of each province from different CO2 flows directions. Five new Energy-carbon emission factors are first performed to provide a more accurate assessment of the province's emissions capacity from different perspectives. Based on the theoretical basis of energy-carbon nexus, the emission reduction simulations considering energy substitution policy can be conducted to forecast the changes of provincial responsibility under different interventions. Results show that some provinces (e.g., Beijing) depend heavily on the supply of other provinces because of their low self-sufficiency rate in electricity, while some provinces (e.g., Guangdong) have high self-sufficiency rate and still emit more CO2 to other provinces to promote their own development. The importance of East China to the system cannot be ignored, but it should also undertake more responsibility for reducing emissions. However, the pace of development in Shandong will slow down because it mainly relies on coal power generation to indirectly promote the development of other provinces. What's more, importing electricity to achieve emission reduction may result in a rebound in indirect emissions and have a negative impact on the region's use of its own energy resources. This paper offers a new way to reveal details of energy-carbon interrelations across provinces and the achievements could provide references for formulating CO2 reduction policies of China electricity trading.

Kaiqiang Zhang, Na Jia, Songyan Li, Lirong Liu (2019)Rapid Determination of Interfacial Tensions in Nanopores: Experimental Nanofluidics and Theoretical Models, In: Langmuir35(27)pp. 8943-8949 American Chemical Society

A rapid and accurate determination of interfacial tensions (IFTs) in nanopores is scientifically and practically significant, while most existing experimental measurements are restricted to the micrometer scale and theoretical calculations are relatively limited. In this study, six series of the IFT measurement tests for the binary CO2–C10, C1–C10, and N2–C10 mixtures are conducted at temperatures (T) of 25.0 and 53.0 °C in a self-manufactured nanofluidic system. Moreover, a nanoscale-extended equation-of-state model considering the effects of the confinement, intermolecular interactions, and disjoining pressure and a semianalytical correlation are proposed to calculate the IFTs of the three mixtures in bulk phase and nanopores. Third, a new Tolman length formulation is developed for the IFT corrections in nanopores. Overall, the calculated IFTs from the two theoretical methods agree well with the measured results for most cases in nanopores. On the other hand, effects of the pore scale, temperature, pressure, and fluid composition on the IFTs of the three mixtures are effectively validated and specifically investigated. One suggestion comes from this work that the two theoretical methods for calculating the IFTs are better to be applied concurrently to minimize errors. Another important future work is to include more pore surface parameter (e.g., wettability) into the theoretical model.

Boyue Zheng, Guohe Huang, Lirong Liu, Mengyu Zhai, Yu Li (2020)Two-pathway perspective for heavy metal emission mitigation: A case study of Guangdong Province, China, In: Science of The Total Environment735139583 Elsevier

Heavy metal emissions have attracted much worldwide attention for its recalcitrance and persistence. In this study, a two-pathway environmental simulation model is developed to uncover heavy metal emissions as induced by intra-provincial production and extra-provincial investments, filling the gap of mitigating heavy metal emissions from separate pathway. This developed model is applied to Guangdong Province, China targeting on the mitigation of Hg, As, Cd, Cr, and Pb emissions. Additionally, emission reduction simulations are implemented on the basis of key sector identification. The effects of intra-provincial production reduction are more notable than those of extra-provincial investment reduction. In addition, mitigation of Hg and As emissions can be achieved through the reduction in both intra-provincial production and extra-provincial investment. In the contrast, it is not expected that the reduction of extra-provincial investment be duo to the emission mitigation of Cd, Cr and Pb. Moreover, an examination of five optimized scenarios reveals that the most remarkable emission mitigation pathway is the reduction of intra- and extra-provincial activities. This study is an indispensable reference for multi-pathway emission mitigation for heavy metals.

Kaiqiang Zhang, Na Jia, Lirong Liu (2019)Semi‐analytical nanoscale‐extended surface tension correlation, In: AIChE Journal65(8) Wiley

Surface tensions (STs) are of critical importance to numerous natural phenomena and practical applications while most existing ST correlations are in the empirical formula- tions and limited to the bulk phase. In this study, a new semi-analytical correlation based on the perturbation theory from the statistical thermodynamics is initially developed to calculate the STs of the various components in bulk and nanoconfined pores. The newly developed ST correlation is validated to be accurate and general- ized in bulk and nanoconfined pores in comparison with the experimentally measured results at a wide range of temperatures. Furthermore, three important patterns with respect to the STs are determined: first, the STs are found to be reduced with the temperature increase but increase when the components become heavier in both bulk and nanoconfined pores; second, the STs of the mixtures tend to be more sensi- tive to the feed ratios at higher temperatures; last but not least, the nanoscale STs of the pure components are slightly lower than the bulk results at the same conditions-

Kaiqiang Zhang, Zhan Meng, Lirong Liu (2019)Factorial two-stage analyses of parameters affecting the oil–gas interface and miscibility in bulk phase and nanopores, In: Journal of Colloid and Interface Science555pp. 740-750 Elsevier

In this paper, a factorial analysis approach is applied to characterize the potential single and interactive factors as well as their effects on the interface and miscibility of three light oil–CO2 systems under 32 different conditions. First, a modified Peng–Robinson equation of state coupled with the parachor model is applied to calculate the vapour–liquid equilibrium and interfacial tensions (IFTs) at a variation of pore radii and different pressures, based on which the MMPs are determined from the diminishing interface method. Second, by means of the factorial-analysis approach and calculated IFTs and minimum miscibility pressures (MMPs), the following five factors are specifically studied to evaluate their main and interactive effects on the IFTs and MMPs: temperature, initial oil and gas compositions, feed gas to oil ratio (feed GOR), and pore radius. It is found that the main and interactive effects of the five factors on the IFTs are inconsistent at different pressures. The effects of the five factors on the MMPs are evaluated quantitatively, which contribute to screen out significant factors, analyze interactions, and identify schemes for the miscible CO2 enhanced oil recovery. The most positive significant main and interactive effects on the MMPs are Factors C (gas composition) and AB (temperature and oil composition), whereas the most negative results are Factors E (pore radius) and AC (temperature and gas compositions). A three-factor analysis indicates that the MMP is substantially reduced in small pores by controlling the percentage of the CH4-dominated gas in the impure CO2 sample and lowering the feed GOR.

LIRONG LIU, Guohe Huang, Chen Lu, Kailong Li, Jiapei Chen, Xiaoyue Zhang, Brian W. Baetz (2019)Projection of Long-Term Hydrological Impacts on Socio-Economic Systems in China

The increasing Greenhous Gases (GHG) concentration in the atmosphere is leading to a changing climate. The GHG emissions are directly or indirectly related to human activities. Meanwhile, human activities are affected by changing climate through various ways. One of the most important way is water availability changes in different industries and different regions. Water resources have close relationships with industrial activities and economic development. Moreover, the virtual water transfer embodied in multi-region trades have significant impacts on water stresses in different regions. Considering the close links among climate change, water, and economy, it is desired to project the long-term hydrological impacts and risks on various industries and regions to improve the awareness and understanding of stakeholders and governments. In this study, a RAS water-extended input-output model (RWEIO) model based on the RegCM is developed to simulate the long-term precipitation, water availability as well as the related socio-economic consequences under various scenarios. A case study of China, which contains 30 provinces, is conducted to illustrate the potential benefits of the proposed RWEIO model and provide scientific support for the policy development for different provinces. To be specific, RegCM is used to project the spatial distributions of precipitation in China for future 100 years. RAS method is adopted to adjust the unbalanced socio-economic structure caused by various scenarios. Input-Output Model aims at exploring the economic and environmental impacts after the policy implementation. It is found that the future water availability in different provinces vary significantly. The precipitation in Xinjiang Province will increase over 50%, while the water availability in south China will decrease slightly. The long-term impacts of water availability are higher in the provinces that rely on Agriculture industry, such as Ningxia, Shandong, Henan and so on. It is recommended that Provinces with rich water resources and high water consumption capacity (e.g., Guangdong, Shandong, Jiangsu) should take the initiative to assume more responsibilities for saving water resources of other provinces through reducing the inter-provincial imports of water-intensive products.

Understanding and controlling confined CO2 fluids in nanopores is at the heart of the CO2 enhanced oil recovery in shale reservoirs. Here, for the first time, qualitative and quantitative static and dynamic behavior of complex confined CO2 fluids in dual-scale nanopores are experimentally performed in nanofluidics, which combines with the theoretical model, the statistical mechanics coupled with the thermodynamic equation of state, to investigate the CO2 utilization in shale reservoirs. In experiment, a series of phase behavior and fluid flow laboratory tests are conducted through a self-manufactured nanofluidic system at different conditions; in theory, a generalized equation of state including the confinements and pore-size distributions and five dynamic models are developed and applied to calculate the vapor–liquid equilibrium and fluid dynamics. Results from this study show that the static behavior has drastic changes in the dual-scale nanopores that the measured saturation pressure of the confined CO2–C10 fluids reduces by 10.19% at T = 25.0 °C and 7.26% at T = 53.0 °C from bulk phase to nanometer scale. Furthermore, under the strong confinements in the dual-scale nanopores, the calculated phase properties including the pore-size distribution effects are more accurate. In addition, effects of the temperature and feed gas to liquid ratio on the confined fluids in nanopores share similar manners with the bulk phase cases. The proposed theoretical models are capable of calculating the static and dynamic behavior of the confined fluids and all calculations have been validated by the experimentally measured results. This study supports the foundation of more general applications pertaining to producing shale fluids and sequestrating CO2 in shale reservoir characterization and exploration.

Kaiqiang Zhang, LIRONG LIU, Guohe Huang (2020)Nanoconfined Water Effect on CO2 Utilization and Geological Storage, In: Geophysical Research Letters47(15)

Understanding nanoconfined water effect on CO2 utilization and storage has tremendous implications in academic research and practical applications, especially for extremely low‐permeability shale reservoirs. Here, a new nanoscale‐extended cubic‐plus association equation of state is developed by including the confinement effects and intermolecular interactions, based on which the phase behavior and interfacial tension of the pure water and water‐CO2 system are accurately calculated. Moreover, three important parameters, caprock‐sealing pressure, maximum storage height, and storage capacity, are quantitatively determined for assessing the potential for the CO2 storage. On the basis of the results from this study, the negative effect of nanoconfiend water can be substantially reduced or even converted to be positive for the CO2 utilization and storage in the shale reservoirs due to the extremely small pore scale as well as the associated strong confinements and intermolecular interactions. Overall, this study supports the foundation of general practical applications pertaining to CO2 utilization and geological storage in unconventional low‐permeability shale formations with existence of nanoconfined water. Plain Language Summary CO2 utilization and geological storage is an emerging topic in energy and environmental community. Nanoconfined water, either from the natural connate or anthropogenic injected/residual source, is an inevitable topic for CO2 utilizations and storages in geological media. However, most existing theories/methodologies specialized in CO2 utilization and geological storage are restricted to the conventional large‐scale porous media without water effect, which may lose effectiveness/accuracy for extremely confined geological media, for example, shale formations. On the other hand, supplies of geological sites with conventional pore scale are badly limited; meanwhile, abundant geological media with unconventional extremely small pores are available and appropriate for CO2 utilization and storage worldwide. This study initially proposes a theoretical method to characterize the CO2 utilization and geological storage at the nanometer scale and investigate the associated nanoconfined water effect. Qualitative and quantitative analyses fill the knowledge gap of the nanoscale water and CO2 behavior. Also, solid scientific results/supports from this study are provided for various academic researches and practical applications, such as the energy and environment and biotechnologies. Therefore, as a comprehensive work consisting of fundamental research and practical applications, this paper shares a wide readership on the areas of science and engineering concurrently. Key Points This study initializes CO2 utilization and geological storage at the nanometer scale and associated nanoconfined water effects Qualitative and quantitative analyses fill the knowledge gap of the nanoscale water and CO2 systems Solid scientific knowledge from this study provides technical supports for various future academic research and practical applications

Kaiqiang Zhang, Na Jia, Lirong Liu, Songyan Li (2020)Main and Interactive Effects of Four Factors on CO2 Storage in Fractured Nanopores, In: Energy & Fuels33(7)pp. 6616-6627 ACS Publications

In this paper, main and interactive effects of four important factors, temperatures, adsorption thicknesses, fracture apertures, and feed CO2 concentrations, on the thermodynamic phase behavior for CO2 storage processes in the fractured nanopores of shale/tight reservoirs with adsorptions are investigated. First, a modified analytical equation of state is developed by considering the effects of confinements and intermolecular interactions, which is applied to predict the confined pure/mixing fluid phase behavior in fractured nanopores coupled with a novel empirical correlation for the adsorption thickness and the fracture geometry equation. Second, the aforementioned four important factors are studied to evaluate their main and interactive effects on the phase behavior of pure CO2, N2, O2, Ar, alkanes of C1–10, and their mixtures. It is found that all the pure and mixing fluid pressures monotonically and linearly increase to different extents with an increasing temperature. Moreover, the pressures/critical shifts and critical properties perform downward and upward parabola curves with respect to the adsorption thicknesses, respectively. On the other hand, the pressures/critical shifts are monotonically decreased, while the critical properties increase with the fracture apertures increasing from 0.01 up to 10 nm and remain constant afterward. By increasing the feed CO2 concentrations, the critical shifts and pressures for all of pure and mixing fluids are increased, while both the critical pressures and temperatures decrease. In addition, three interactive effects on the phase behavior are analyzed that the effect of a single factor behaves differently with the variations of any other factors. Finally, the amounts of the N2, O2, Ar, and light alkanes of C1–4 are suggested to be controlled for CO2 storage in the fractured nanopores because additions of these components strongly affect the mixture phase behavior.

Lirong Liu, Guohe Huang, Brian Baetz, Charley Z. Huang, Kaiqiang Zhang (2019)Integrated GHG emissions and emission relationships analysis through a disaggregated ecologically-extended input-output model; A case study for Saskatchewan, Canada, In: Renewable and Sustainable Energy Reviews106pp. 97-109 Elsevier

Facing the potential conflict between economic and environmental challenges, it is essential to investigate the integrated GHG emissions and the emission relationships of all industries in a socio-economic system to support formulation of industrially related legislation. In this study, a disaggregated ecologically-extended input-output (DECEIO) model is developed to investigate integrated GHG emissions and the emission relationships of various industries. A special case study for the Province of Saskatchewan, Canada, is conducted to illustrate the potential benefits of its use in the formulation of industrially related legislation. A disaggregated analysis that contains three GHG types and four emission sources is conducted to gain more insight into the complicated interactions between different industries. It is found that all kinds of emission sources and GHG types should be considered to comprehensively identify the characteristics of emission flows in the socio-economic system. The competitive relationships reflect good interactions in the GHG emission flows and a mutualism relationship reveals effective pathways to mitigate carbon emissions in two sectors simultaneously. In the Province of Saskatchewan, the Agriculture and Forestry sector, Electric Power Generation, Transmission and Distribution sector, Construction sector and Household Consumption sector all rank at the top for GHG emissions and their relationships are mutualistic. Thus, it is vital to propose effective industrial legislation for these industries to realize GHG emission reduction targets.

Kaiqiang Zhang, Na Jia, Songyan Li, Lirong Liu (2018)Millimeter to nanometer-scale tight oil–CO2 solubility parameter and minimum miscibility pressure calculations, In: Fuel220pp. 645-653 Elsevier

In this paper, solubility parameters and minimum miscibility pressures (MMPs) of five tight oil–CO2 systems are calculated in millimeter to nanometer scales. First, the Peng–Robinson equation of state (PR-EOS) is modified to calculate the vapour–liquid equilibrium in nanopores by considering the effects of capillary pressure and shifts of critical temperature and pressure. Second, a thermodynamic formula of the solubility parameter is derived and presented from the modified PR-EOS, which is applied to calculate the solubility parameters in nanopores. Third, the MMPs are estimated from the newly-developed solubility parameter-based method, at which the difference between the solubility parameters of oil and gas phases approximately equals to . The modified PR-EOS is found to be accurate for predicting the oil–CO2 phase behaviour. It is found that are almost equivalent at low pressures but with the pressure increase, at a larger pore radius becomes greater. The estimated MMPs are found to agree well with the measured MMPs from the coreflood and slim-tube tests in bulk phase and with the determined MMPs from the diminishing interface method in nanopores, whose average absolute relative deviations (AARD) are within 4.38% except for two abnormal cases. A smaller nanopore is found to contribute to the oil–gas solubility (i.e., a lower ) and the MMP is also decreased with the pore radius. Moreover, the temperature increase and addition of CH4 into the oil and gas phases lead to a larger , which make the oil and gas phases become more difficult to be soluble so that the corresponding MMPs increase. On the contrary, the oil–gas solubility is beneficial from the addition of C2H6 into gas phase so that the MMP is reduced. Overall, the effects of temperature, initial oil and injection gas compositions on the MMP are found to be weakened in nanopores.

Kaiqiang Zhang, Na Jia, Lirong Liu (2018)Nanoscale-extended alpha functions for pure and mixing confined fluids, In: Fluid Phase Equilibria482pp. 64-80 Elsevier

In this paper, two new nanoscale-extended attractive (alpha) functions in Soave and exponential types are developed for the first time, which are applied and evaluated for the calculations of the thermodynamic and phase properties of confined fluids coupled with a modified equation of state (EOS). Moreover, a novel method is proposed and verified to determine the nanoscale acentric factors. The behaviour of several important parameters, i.e., minimum reduced temperature, nanoscale acentric factor, alpha function and its first and second derivatives, are specifically analyzed at different temperatures and pore radii. The newly-developed alpha functions are validated to accurately calculate the thermodynamic and phase properties in bulk phase (rp = 1000 nm) and nanopores. The minimum reduced temperature from the Soave alpha function occurs at the acentric factor of ω = −0.295211 while the exponential function is monotonically related to the temperatures without any minimum conditions. Moreover, the acentric factors and intermolecular attractivities are found to be increased with the pore radius reductions at most temperatures, wherein they remain constant or slightly increase by reducing the pore radius at rp ≥ 50 nm while become quickly increased at rp 

Kaiqiang Zhang, Na Jia, Lirong Liu (2019)CO2 storage in fractured nanopores underground: Phase behaviour study, In: Applied Energy238pp. 911-928 Elsevier

In this paper, thermodynamic phase behaviour, implications, and strategies for the CO2 storage process in the fractured tight/shale reservoirs (i.e., nanoproes) with adsorptions are studied. First, an analytical equation of state is modified to calculate the nanoscale phase behaviour by considering the effects of pore radius and molecule–molecule interactions. Second, a new empirical correlation for calculating the adsorption thickness in nanopores is initially developed. The modified equation of state coupled with the new adsorption thickness correlation and fracture geometry equation is used to calculate the phase behaviour of confined pure and mixing CO2 streams in fractured nanopores with adsorptions. Third, the pressure–volume diagrams, pressure–temperature diagrams, and critical properties of 12 pure substances of CO2, N2, and alkanes of C1–10 and 12 binary and ternary CO2-dominated mixtures are studied. The calculated pressures for all cases in nanopores with and without the adsorptions and fractures are reduced with the system volume increases but increased by increasing the system temperature with constant compositions. The pressures in nanopores are always larger than those in bulk phase at small volumes but in good agreement at large volumes. In comparison with the N2 or C1–10, the pure CO2 is more easily transited to be a liquid or supercritical phase. Any additions of contaminations (e.g., N2 or C1–10) into the pure CO2 increase the pressures in the pressure–volume or temperature diagram while decrease the critical properties to different extent, especially in nanopores, wherein the N2 exerts the strongest effect and the effects of the alkanes are weakened with the carbon number increase. Overall, three optimum strategies are determined for CO2 storage projects in the deep tight/shale formations as follows: large pore radii, purified CO2 streams, and low temperatures.