Performance Assessment Of A Modified De-carbonization Coal-fired Power Plant Incorporating A Supercritical CO₂ Power Cycle And An Absorption Heat Transformer

At present,the contradiction between the growing energy demand and the environmental pollution is more and more prominent,and the greenhouse gas emission has received wide attention all over the world.Therefore,reducing carbon dioxide emissions from coal-fired power plants has become increasingly urgent and critical to global sustainable development,especially for developing countries with high levels of coal consumption.Therefore,it is imperative to control the emission of greenhouse gases.The traditional carbon capture process based on monoethanolamine(MEA)in coal-fired power plants has some shortcomings.De-carbonization of coal-fired power stations carries a large energy efficiency penalty.The supercritical carbon dioxide cycle can efficiently utilize the waste heat of different temperature grades,and an absorption heat transformer can realize the quality utilization of medium temperature heat.This paper proposes a de-carbonization coal-fired power plant which integrates the supercritical carbon dioxide cycle and an absorption heat transformer.The system has the following characteristics:(1)with supercritical carbon dioxide as waste heat recovery,recycling de-carbonization unit waste heat cooling heat(carbon dioxide,multistage compression between hot and cold and extraction steam cooling heat),through the turbine to generate electricity,carbon dioxide offset part for de-carbonization extraction and reduce the quantity of work units,reduce decarburization process efficiency punishment;(2)through the second type of absorption heat pump recovery de-carbonization unit of a large number of medium temperature waste heat(carbon dioxide cooling heat and multi-stage compression intermediate cooling heat),produce part of the steam supply reboiler,thus saving the steam turbine extraction,further increase the unit output;(3)Use supercritical carbon dioxide exhaust steam to preheat the air,save part of the flue gas to heat the condensate water/water supply,reduce the heat recovery steam extraction,and increase the output of the unit.In this study,the reference system and the process flow of the proposed new system are introduced in detail.Ebsilon Professional 13.0 software and Aspen Plus software are used to simulate the case system and the modules in the proposed new system.The basic assumptions of the model and the calculation methods of energy balance,mass balance and technical and economic analysis are given.The COE and COA are used to evaluate and compare the technical and economic performance of the two systems.The results show that the power generation efficiency and exergy efficiency of the new system reach 34.38%and 33.36%respectively,and the power generation cost(COE)and carbon dioxide emission reduction cost(COA)are $92.21/MWh and $46.27/tCO2 respectively,which have advantages compared with the reference system.