| Carbon dioxide is the main greenhouse gas.With the development of human industrial production,the emission of carbon dioxide is becoming more and more serious,and the emission reduction of CO2 is urgent.In many industrial production,thermal power generation is the main source of carbon dioxide emissions.Therefore,reducing the carbon dioxide emissions from thermal power generation is the key to reduce the greenhouse effect.The carbon capture technology after combustion is the main method to reduce the carbon dioxide emission.However,in the chemical absorption method,the regeneration of reboiler requires the external heat supply,which is often provided by the extraction steam in the power plant,which is the main reason for the decline of the thermal efficiency of the whole system.Therefore,it is the most important to study how to reduce the energy consumption of carbon capture in coupling system.Taking natural gas steam combined cycle as the research object,the coupling systems of combined cycle and carbon capture unit based on MEA solution and AMP-PZ solution were built by Ebsilon.In the two coupling systems,the extraction after the intermediate pressure cylinder is set respectively,and four extraction modes are adopted,i.e.extraction back to deaerator,extraction exchange heat and go back to deaerator,extraction back to condenser,extraction go through small steam turbine and go back to deaerator.The thermal efficiency,output power,energy punishment and auxiliary power consumption of different schemes are compared.The simulation results show that the scheme of using AMP-PZ solution and the scheme of the steam extraction with the small steam turbine has the highest thermal efficiency of 52.92%and the lowest energy penalty of 4.67%.Based on the extraction scheme with the highest thermal efficiency,the efficiency and energy punishment of NGCC and coupling system with air cooling,mechanical ventilation cooling and water cooling are compared.The results show that without carbon capture system,the total power of direct water cooling unit and mechanical ventilation cooling unit is the same,889.37MW,higher than that of direct air cooling unit,881.94MW;the net power of direct water cooling unit is the highest,followed by evaporative cooling unit,and the net power of air cooling unit is the lowest,882.49MW,881.34MW and 870.00MW respectively.For the case of coupling system,the total power of air cooling unit is the highest,which is 819.79MW,while the total power of direct water cooling unit and mechanical ventilation cooling unit is 815.17MW;the net power of direct water cooling unit is the highest.which is 809.04MW,followed by air cooling unit,which is 807.82MW.and the lowest is mechanical ventilation cooling unit,which is 807.63MW.The proportion of auxiliary energy consumption is different,which will lead to different ranking of total power and net power in different schemes.Through the analysis of different cooling modes and energy consumption distribution of auxiliary equipment,the next step direction for system coupling improvement is provided. |
