Carbon Capture Sscheme And Optimization Of Nature Gas Combined Cycle Unit

Power generation using Fossil fuels releases a large amount of CO₂,which will intensify the greenhouse effect.The technology of Carbon capture of CO₂concrete accords with the policy of energy saving and emission reduction in china.Natural Gas Combined Cycles（NGCC）power generating units have higher efficiency than coal-fired units,meanwhile discharge less CO₂ gas,which will play a greater role in the future.However,high energy consumption is the biggest challenge for NGCC power units to carry out carbon capture and storage.In this paper,a simulation study on MEA carbon capture and calcium-based absorbent carbon capture was performed using Aspen Plus.The simulation results show that:（1）With the increase of CO₂ capture rate,the absorbent flow rate,the heat recovery energy of the reboiler and the rich liquid load increase;as the concentration of MEA solution increases,the heat loss of the reboiler decreases.The temperature of the tower rises,the rich liquid load increases,and the absorbent flow rate decreases.（2）The decrease of the purge rate will increase the mass flow rate of circulating solid materials,CaO,CaCO₃,and also increase the calcination energy consumption,but the mass flow rate of fresh calcium-based absorbent supplemented to the carbon capture system Will decrease;the increase of gas-solid separation coefficient will increase the mass flow rate of circulating solid materials,CaO,CaCO₃,and also increase the energy consumption of calcination,but the fresh calcium-based absorbent added to the carbon capture system The mass flow rate will decrease;the increase of the calcium-carbon ratio will increase the mass flow rate of the solid materials in each part of the carbon capture system,and the calcination energy consumption will also increase;the reasonable use of clean flue gas and high-temperature CO₂ heat can be improved.Output power to reduce capture energy consumption.The results shows that,,the MEA carbon capture process has a thermal efficiency of 1.3%relative to the calcium-based absorbent carbon capture process and a heat dissipation rate of 862 KJ/（KW?h）under design conditions.While,the initial investment cost,equal annual amortization cost,operation and maintenance cost,power generation cost,decarbonization cost,and power generation cost of the entire coupling system were increased comparing with the calcium-based absorbent method carbon capture system.The reason is that the MEA carbon capture process requires large equipment and draws a large amount of steam from the medium and low pressure cylinders of the unit to provide a heat source for the reboiler of the analytical tower,which decreases the system economy.The initial investment cost,equal annual amortization cost,operation and maintenance cost,power generation cost,decarbonization cost of the system are 234 million yuan,29.31 million yuan,9.95million yuan,and 140 yuan/（MW?h）,450 yuan/t CO₂.higher than the calcium-based absorbent method.In summary,the MEA method is superior in terms of thermal performance;in terms of economy,the calcium-based absorbent method is better.