Browsing by Autor "Muhammad Akram"

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    Bioenergy with carbon capture and storage (BECCS) potential in jet fuel production from forestry residues: A combined Techno-Economic and Life Cycle Assessment approach
    (Elsevier BV, 2022) Maria Fernanda Rojas Michaga; Stavros Michailos; Muhammad Akram; Evelyn Cardozo; Kevin J. Hughes; D.B. Ingham; Mohamed Pourkashanian
    In this study, the economic and environmental feasibility of a process configuration based on the Bioenergy and Carbon Capture and Storage (BECCS) concept is assessed. The research analyses the production of jet fuel from forestry residues-derived syngas via the Fischer-Tropsch (FT) technology. Further, the CO2 removed in the syngas cleaning section is not released to the environment, instead it is permanently sequestrated. The produced Sustainable Aviation Fuel (SAF) has the potential to achieve negative emissions. The present research is a one-of-a-kind study for the jet fuel production within the BECCS concept. The process has been modelled within the Aspen Plus and Matlab software to obtain detailed and realistic mass and energy balances. Based on these balances, the technical, economic and environmental parameters have been calculated. Based on a plant that treats 20 dry-t/h of forest residues, 1.91 t/h of jet fuel are produced, while 11.26 t/h of CO2 are permanently stored. The inclusion of the CCS chain in the biorefinery increase the minimum jet fuel selling price from 3.03 £/kg to 3.27 £/kg. The LCA results for global warming show a favourable reduction in the BECCS case, in which negative emissions of −121.83 gCO2eq/MJ of jet fuel are achieved, while without CCS case exhibits GHG emissions equal to 15.51 gCO2eq/MJ; in both cases, the multi-functionality is faced with an energy allocation approach. It is, then, evident the significant environmental advantages of the BECCS process configuration. Nevertheless, financial feasibility can only be attained through the implementation of existing policy schemes and the formulation of new strategies that would reward negative emissions. The application of the UK’s policy “Renewable Transport Fuel Obligation” and a hypothetical scheme that rewards negative CO2 emissions, breaks-even the Minimum Jet fuel Selling Price (MJSP) at 1.49 £/kg for a certificate and carbon price of 0.20 £/certificate and 246.64 £/tonne of CO2.
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    Sustainable aviation fuel (SAF) production through power-to-liquid (PtL): A combined techno-economic and life cycle assessment
    (Elsevier BV, 2023) Maria Fernanda Rojas Michaga; Stavros Michailos; Evelyn Cardozo; Muhammad Akram; Kevin J. Hughes; D.B. Ingham; Mohamed Pourkashanian
    The current research critically evaluates the technical, economic, and environmental performance of a Power-to-Liquid (PtL) system for the production of sustainable aviation fuel (SAF). This SAF production system comprises a direct air capture (DAC) unit, an off-shore wind farm, an alkaline electrolyser and a refinery plant (reverse water gas shift coupled with a Fischer-Tropsch reactor). The calculated carbon conversion efficiency, hydrogen conversion efficiency, and Power-to-liquids efficiency are 88 %, 39.16 % and 25.6 %, respectively. The heat integration between the refinery and the DAC unit enhances the system's energy performance, while water integration between the DAC and refinery units and the electrolyser reduces the demand for fresh water. The economic assessment estimates a minimum jet fuel selling price (MJSP) of 5.16 £/kg. The process is OPEX intensive due to the electricity requirements, while the CAPEX is dominated by the DAC unit. A Well-to-Wake (WtWa) life cycle assessment (LCA) shows that the global warming potential (GWP) equals 21.43 gCO2eq/MJSAF, and is highly dependent on the upstream emissions of the off-shore wind electricity. Within a 95 % confidence interval, a stochastic Monte Carlo LCA reveals that the GWP of the SAF falls below the UK aviation mandate treshold of 50 % emissions reduction compared to fossil jet fuel. Moreover, the resulting WtWa water footprint is 0.480 l/MJSAF, with the refinery’s cooling water requirements and the electricity’s water footprint to pose as the main contributors. The study concludes with estimating the required monetary value of SAF certificates for different scenarios under the UK SAF mandate guidelines.