Dr Bolaji Shemfe


Research Fellow
MSc PhD
+44 (0)1483 684433
39 BA 01

Academic and research departments

Centre for Environment and Sustainability.

About

My qualifications

2013 - 2016
PhD
Cranfield University
2009 - 2010
MSc
University of Surrey

Research

Research interests

Research projects

Youtube video

Publications

Shemfe MB, Fidalgo B, Gu S (2015) Heat integration for bio-oil hydroprocessing coupled with aqueous phase steam reforming, CHEMICAL ENGINEERING RESEARCH & DESIGN107pp. 73-80 INST CHEMICAL ENGINEERS
Biofuels have been identified as a mid-term GHG emission abatement solution for decarbonising the transport sector. This study examines the techno-economic analysis of biofuel production via biomass fast pyrolysis and subsequent bio-oil upgrading via zeolite cracking. The aim of this study is to compare the techno-economic feasibility of two conceptual catalyst regeneration configurations for the zeolite cracking process: (i) a two-stage regenerator operating sequentially in partial and complete combustion modes (P-2RG) and (ii) a single stage regenerator operating in complete combustion mode coupled with a catalyst cooler (P-1RGC). The designs were implemented in Aspen Plus® based on a hypothetical 72 t/day pine wood fast pyrolysis and zeolite cracking plant and compared in terms of energy efficiency and profitability. The energy efficiencies of P-2RG and P-1RGC were estimated at 54% and 52%, respectively with corresponding minimum fuel selling prices (MFSPs) of £7.48/GGE and £7.20/GGE. Sensitivity analysis revealed that the MFSPs of both designs are mainly sensitive to variations in fuel yield, operating cost and income tax. Furthermore, uncertainty analysis indicated that the likely range of the MFSPs of P-1RGC (£5.81/GGE - £11.63/GGE) at 95% probability was more economically favourable compared with P-2RG, along with a penalty of 2% reduction in energy efficiency. The results provide evidence to support the economic viability of biofuel production via zeolite cracking of pyrolysis-derived bio-oil.
Sadhukhan Jhuma, Joshi N, Shemfe Mobolaji, Lloyd JR (2017) Life Cycle Assessment of Sustainable Raw Material Acquisition for Functional Magnetite Bionanoparticle Production,Journal of Environmental Management199pp. 116-125 Elsevier
Magnetite nanoparticles (MNPs) have several applications, including use in medical diagnostics, renewable energy production and waste remediation. However, the processes for MNP production from analytical-grade materials are resource intensive and can be environmentally damaging. This work for the first time examines the life cycle assessment (LCA) of four MNP production cases: (i) industrial MNP production system; (ii) a state-of-the-art MNP biosynthesis system; (iii) an optimal MNP biosynthesis system and (iv) an MNP biosynthesis system using raw materials sourced from wastewaters, in order to recommend a sustainable raw material acquisition pathway for MNP synthesis. The industrial production system was used as a benchmark to compare the LCA performances of the bio-based systems (cases ii-iv). A combination of appropriate life cycle impact assessment methods was employed to analyse environmental costs and benefits of the systems comprehensively. The LCA results revealed that the state-of-the-art MNP biosynthesis system, which utilises analytical grade ferric chloride and sodium hydroxide as raw materials, generated environmental costs rather than benefits compared to the industrial MNP production system. Nevertheless, decreases in environmental impacts by six-fold were achieved by reducing sodium hydroxide input from 11.28 to 1.55 in a mass ratio to MNPs and replacing ferric chloride with ferric sulphate (3.02 and 2.59, respectively, in a mass ratio to MNPs) in the optimal biosynthesis system. Thus, the potential adverse environmental impacts of MNP production via the biosynthesis system can be reduced by minimising sodium hydroxide and substituting ferric sulphate for ferric chloride. Moreover, considerable environmental benefits were exhibited in case (iv), where Fe(III) ions were sourced from metal-containing wastewaters and reduced to MNPs by electrons harvested from organic substrates. It was revealed that 14.4 kJ and 3.9 kJ of primary fossil resource savings could be achieved per g MNP and associated electricity recoveries from wastewaters, respectively. The significant environmental benefits exhibited by the wastewater-fed MNP biosynthesis system shows promise for the sustainable production of MNPs.
This study examines the GHG emissions associated with producing bio-hydrocarbons via fast pyrolysis of Miscanthus. The feedstock is then upgraded to bio-oil products via hydroprocessing and zeolite cracking. Inventory data for this study were obtained from current commercial cultivation practices of Miscanthus in the UK and state-of-the-art process models developed in Aspen Plus®. The system boundary considered spans from the cultivation of Miscanthus to conversion of the pyrolysis-derived bio-oil into bio-hydrocarbons up to the refinery gate. The Miscanthus cultivation subsystem considers three scenarios for soil organic carbon (SOC) sequestration rates. These were assumed as follows: (i) excluding (SOC), (ii) low SOC and (iii) high (SOC) for best and worst cases. Overall, Miscanthus cultivation contributed moderate to negative values to GHG emissions, from analysis of excluding SOC to high SOC scenarios. Furthermore, the rate of SOC in the Miscanthus cultivation subsystem has significant effects on total GHG emissions. Where SOC is excluded, the fast pyrolysis subsystem shows the highest positive contribution to GHG emissions, while the credit for exported electricity was the main ?negative? GHG emission contributor for both upgrading pathways. Comparison between the bio-hydrocarbons produced from the two upgrading routes and fossil fuels indicates GHG emission savings between 68 and 87%. Sensitivity analysis reveals that bio-hydrocarbon yield and nitrogen gas feed to the fast pyrolysis reactor are the main parameters that influence the total GHG emissions for both pathways.
Shemfe Mobolaji, Gadkari Siddharth, Yu E, Rasul S, Scott K, Head I, Gu Sai, Sadhukhan Jhuma (2018) Life cycle, techno-economic and dynamic simulation assessment of bioelectrochemical systems: A case of formic acid synthesis,Bioresource Technology255pp. 39-49 Elsevier
A novel framework integrating dynamic simulation (DS), life cycle assessment (LCA) and techno-economic assessment (TEA) of bioelectrochemical system (BES) has been developed to study for the first time wastewater treatment by removal of chemical oxygen demand (COD) by oxidation in anode and thereby harvesting electron and proton for carbon dioxide reduction reaction or reuse to produce products in cathode. Increases in initial COD and applied potential increase COD removal and production (in this case formic acid) rates. DS correlations are used in LCA and TEA for holistic performance analyses. The cost of production of HCOOH is ¬0.015?0.005g?1 for its production rate of 0.094?0.26kgyr?1 and a COD removal rate of 0.038?0.106kgyr?1. The life cycle (LC) benefits by avoiding fossil-based formic acid production (93%) and electricity for wastewater treatment (12%) outweigh LC costs of operation and assemblage of BES (?5%), giving a net 61MJkg-1HCOOH saving.
Bioelectrochemical systems (BESs) have been catalogued as a technological solution to three pressing global challenges: environmental pollution, resource scarcity, and freshwater scarcity. This study explores the social risks along the supply chain of requisite components of BESs for two functionalities: (i) copper recovery from spent lees and (ii) formic acid production via CO2 reduction, based on the UK?s trade policy. The methodology employed in this study is based on the UNEP/SETAC guidelines for social life-cycle assessment (S-LCA) of products. Relevant trade data from UN COMTRADE database and generic social data from New Earth?s social hotspot database were compiled for the S-LCA. The results revealed that about 75% of the components are imported from the European Union. However, the social risks were found to vary regardless of the magnitude or country of imports. ?Labour and Decent Work? was identified as the most critical impact category across all countries of imports, while the import of copper showed relatively higher risk than other components. The study concludes that BESs are a promising sustainable technology for resource recovery from wastewater. Nevertheless, it is recommended that further research efforts should concentrate on stakeholder engagement in order to fully grasp the potential social risks.
Gadkari Siddharth, Shemfe Mobolaji, Sadhukhan Jhuma (2019) Microbial fuel cells: a fast converging dynamic model for assessing system performance based on bioanode kinetics,International Journal of Hydrogen Energy44(29)pp. 15377-15386 Elsevier
In this work, a dynamic computational model is developed for a single chamber microbial fuel cell (MFC), consisting of a bio-catalyzed anode and an air-cathode. Electron transfer from the biomass to the anode is assumed to take place via intracellular mediators as they undergo transformation between reduced and oxidized forms. A two-population model is used to describe the biofilm at the anode and the MFC current is calculated based on charge transfer and Ohm's law, while assuming a non-limiting cathode reaction rate. The open circuit voltage and the internal resistance of the cell are expressed as a function of substrate concentration. The effect of operating parameters such as the initial substrate (COD) concentration and external resistance, on the Coulombic efficiency, COD removal rate and power density of the MFC system is studied. Even with the simple formulation, model predictions were found to be in agreement with observed trends in experimental studies. This model can be used as a convenient tool for performing detailed parametric analysis of a range of parameters and assist in process optimization.