Abstract
The Allam cycle is a novel cycle that capitalizes on the unique thermodynamic properties of supercritical CO2 and the advantages of oxy-fuel combustion for power generation and CO2 capture. This study aims to confirm the outstanding performance of a coal-fired Allam cycle and with the aid of an exergetic analysis to provide detailed important information on the real thermodynamic inefficiencies within the cycle. The results show that the overall exergetic efficiency is 40.6%, with near 100% carbon capture. The highest exergy destruction occurs within the gasifier, which contributes 29.1% to the overall exergy destruction, followed by the combustion chamber (17.4%), the air separation unit (7.4%) and the turbine (4.1%). In addition, the results obtained from the exergetic analysis in this study are compared to those of a gas-fired Allam cycle. The contribution of the exergy destruction of the combustor in the gas-fired Allam cycle is higher than the total share of the gasifier and the combustor of the coal-fired Allam cycle in the system exergy destruction. The sensitivity analysis shows that the specific power demand of the air separation unit, as well as the turbine inlet pressure, outlet pressure and isentropic efficiency have significant impacts on the overall exergetic efficiency.
Highlights
Coal is regarded as one of the largest resources for power generation worldwide
We present the findings of the thermodynamic and exergetic analysis of the coal-fired Allam cycle which forms the bedrock for further discussions on the effects of important process parameters on cycle performance
The net efficiency of the coal-fired Allam cycle in this study is 30.7 %; the principal parasitic loads of the plant as shown in Table 5 below include: The Air Separation Unit, the CO2, syngas, and oxidant compressor
Summary
Coal is regarded as one of the largest resources for power generation worldwide. According to International Energy Agency (IEA), coal-fired power generation increased by approximately 3% in 2017 and in 2018, reaching a new peak above 10,000 TWh [1]. Over 30% of the global energy demand and over 40% of the electricity generated is derived from coal, owing to the fact that it is a secure and relatively low‐cost source of energy, and the resources are abundant and broadly distributed geographically [2]. With the significantly increasing demand in global energy, comes the challenge of increasing CO2 emissions, of which coal-fired power plants are major contributors. In a bid to reduce CO2 emissions from power generating plants, several solutions have been proposed and developed. The carbon capture and storage (CCS) is one of such Incorporation of this solution presents detrimental efficiency penalty and increased price of electricity due to the high cost of additional equipment. Novel technologies that generate electricity from coal with reduced CO2 emissions and high efficiency are being developed
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
