Thermodynamic limitations to direct CO2 utilisation within a small-scale integrated biomass power cycle

Greencorn, M. J., Jackson, S. D. , Hargreaves, J. S.J. , Datta, S. and Paul, M. C. (2022) Thermodynamic limitations to direct CO2 utilisation within a small-scale integrated biomass power cycle. Energy Conversion and Management, 269, 116144. (doi: 10.1016/j.enconman.2022.116144)

Abstract

Partially recycling CO2-rich exhaust gases from a syngas fuelled internal combustion engine to a biomass gasifier has the capability to realise a new method for direct carbon dioxide utilisation (CDU) within a bioenergy system. Simulation of an integrated, air-blown biomass gasification power cycle was used to study thermodynamic aspects of this emerging CDU technology. Analysis of the system model at varying gasifier air ratios and exhaust recycling ratios revealed the potential for modest system improvements under limited recycling ratios. Compared to a representative base thermodynamic case with overall system efficiency of 28.14 %, employing exhaust gas recycling (EGR) enhanced gasification system efficiency to 29.24 % and reduced the specific emissions by 46.2 g-CO2/kWh. Further investigation of the EGR-enhanced gasification system revealed the important coupling between gasification equilibrium temperature and exhaust gas temperature through the syngas lower heating value (LHV). Major limitations to the thermodynamic conditions of EGR-enhanced gasification as a CDU strategy result from the increased dilution of the syngas fuel by N2 and CO2 at high recycling ratios, restricting equilibrium temperatures and reducing gasification efficiency. N2 dilution in the system reduces the efficiency by up to 2.5 % depending on the gasifier air ratio, causing a corresponding increase to specific CO2 emissions. Thermodynamic modelling indicates pre-combustion N2 removal from an EGR-gasification system could decrease specific CO2 emissions by 9.73 %, emitting 118.5 g/kWh less CO2 than the basic system.

• Item Type: Articles
• Additional Information: This research was supported by the University of Glasgow’s Lord Kelvin/Adam Smith (LKAS) PhD Scholarship.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Hargreaves, Professor Justin and Greencorn, Mr Michael and Paul, Professor Manosh and Jackson, Professor David and Datta, Souvik

Creator Roles

Greencorn, M.: Conceptualization, Methodology, Software, Validation, Investigation, Formal analysis, Visualization, Writing – original draft, Writing – review and editing
Jackson, D.: Supervision, Writing – review and editing
Hargreaves, J.: Supervision, Writing – review and editing
Datta, S.: Supervision, Writing – review and editing
Paul, M.: Conceptualization, Supervision, Writing – review and editing, Project administration, Funding acquisition

• Authors: Greencorn, M. J., Jackson, S. D., Hargreaves, J. S.J., Datta, S., and Paul, M. C.
• College/School: College of Science and Engineering > School of Chemistry; College of Science and Engineering > School of Engineering > Systems Power and Energy
• Journal Name: Energy Conversion and Management
• Publisher: Elsevier
• ISSN: 0196-8904
• ISSN (Online): 1879-2227
• Published Online: 23 August 2022
• Copyright Holders: Copyright © The Authors
• First Published: First published in Energy Conversion and Management 269:116144
• Publisher Policy: Reproduced under a Creative Commons license