Study On Integrated Optimization Of Thermodynamic System In Coal Fired Power Plants With Post-combustion Carbon Capture

Currently,coal-fired power plants generally use chemical alcohol amine to get on with CO₂ capture,this method has the advantages such as large capture volume?high absorption efficiency and the technology is more mature.However,carbon capture system consumes large amounts of turbine steam,resulting in a drop of 11%-15%in power plant efficiency.Taking a 660MW secondary reheat coal fired power plants with post-combustion carbon capture as an example,based on the EBSILON platform,it is simulated as steam in the mid and low pressure cylinders'connecting pipe is directly supplied to the reboiler and steam go through carbon capture turbine first,then supplied to the reboiler.Comparing these two projects,the installation of carbon capture turbine can increase the thermal efficiency of the entire plant cycle.Aiming at the selection of the steam source location of the carbon capture steam turbine,first reheat cold section and hot section,second reheat cold section and hot section,these four new steam supply schemes were designed and set up.Simulating by EBSILON platform,carbon capture turbine steam source locations had been compared and calculated,and applying the method of unit consumption analysis to analyze and discuss the system energy consumption distribution.The result shows that the first reheat hot section is the best steam source for the carbon capture system.The thermal efficiency of the entire plant is 44.99%,which is 2.37%higher than that of the conventional steam supply system.Based on the optimum steam supply scheme,two overhead gas recovery schemes using heat exchangers are proposed based on the recovery of overhead gas energy to condensate.The simulation calculation appears that the recovery of energy to replace9#,10#low-pressure heaters has unit optimal thermal economy,it is the best integration scheme.The scheme can increase the thermal efficiency o f carbon capture units by 0.27%.