Integrated Research And Economic Evaluation Of Carbon Capture System In Gas Power Plant

Thermal power plant is a stable and concentrated long-term emission source of CO₂.In order to alleviate environmental problems,it is necessary to adopt effective decarbonization methods for existing units of power plant.There are few demonstration projects of CO₂capture in gas power plants in China,and the engineering experience for reference is limited.Therefore,the development of large-scale decarbonization process in gas-fired power plants still needs a lot of research.In this paper,the integrated characteristics and thermodynamic analysis of the CO₂ capture system by alkanolamine process and gas power plant are studied.Taking PG 9371FB gas turbine and its combined cycle unit as the research object,GT-PRO software is used to model the gas-steam combined cycle unit,and on this basis,Aspen Plus software is used to establish the carbon capture process flow,which accurately simulates the operation status of the carbon capture process.In addition,sensitivity analysis and optimization of the influence of some carbon capture process parameters on regeneration energy consumption are carried out in this paper.The thermal distribution characteristics of the integrated system are studied by the method of exergy analysis,and the sensitivity analysis of the generation cost of the integrated carbon capture unit is carried out.The results show that after the integration of carbon capture system,the performance parameters of the unit are reduced to a certain extent,and the integration of carbon capture system has the most obvious impact on the gas-steam combined cycle steam system.The performance of the integrated carbon capture unit before and after different loads is analyzed and compared.It is found that with the decrease of the gas turbine load,the performance parameters of the system decrease linearly,but there is a certain compensation for the performance penalty of the integrated carbon capture unit to the system.In addition,after the integration of carbon capture units,the production efficiency of power plants has decreased by 7.58 percentage points.Among them,the balance of gas turbine is basically unaffected;the main factor affecting the balance of waste heat boiler is the heat transfer process of the boiler;the main factor affecting the balance of steam turbine is the expansion work process of the turbine.The main sources of carbon capture system loss are flue gas cooling in flue gas pretreatment system,reboiler heating in regeneration tower and heat exchange between rich and poor liquids.After the integration of carbon capture units in power plants,the unit power generation cost of integrated units increased by about 28.8%.For each increase in fuel price of 1 yuan/Nm³,the cost of power generation increases by 222.5 yuan/MW·h;for every increase in ambient temperature of 1?,the cost of power generation increases by 1.57 yuan/MW·h;and for every increase in CO₂ price of 1 yuan,the cost of power generation increases by 0.58 yuan/MW·h.In addition,compared with the pre-integrated unit,the increasing proportion of power generation cost of integrated unit decreases gradually with the increase of carbon price.