Simulation Study On Energy Saving Of Amine Decarbonization Regeneration System Based On Heat Pump

At present,MEA chemical absorption method is the mainstream technology for industrial application of carbon dioxide capture and separation.But there is a problem of high energy consumption for MEA regeneration.Because MEA regeneration requires high reaction enthalpy,its regenerative energy consumption accounts for up to 80%of the total energy consumption of the entire capture and separation system.In the regeneration tower of the MEA decarbonization system,a large amount of cold load and heat load are used to cool the overhead gas and to heat the tower liquid.In view of the high energy consumption of MEA regeneration,this topic is based on the advantages of heat pump technology,applied to the MEA decarbonization system,to maximize to use the cold load and heat load,that is to achieve the purpose for reducing the energy consumption of MEA regeneration.Firstly,the standard MEA decarburization process was simulated by Aspen HYSYS software.Secondly,the pinch analysis method is used to analyze the relevant data of the standard MEA decarbonization system,which provides a reference for the heat pump cross-pinch setting and the feasibility of integrating three common industrial heat pumps into the MEA decarbonization system.Finally,by means of simulating the feasible MEA decarbonization system integrated heat pump model,the study analysises of heat pump parameters,heat pump type,the effect of system regeneration and energy saving.The study shows that the MEA decarbonization system can be integrated with two heat pump types:closed heat pump and tower top gas phase compression heat pump.The results anslyse the effect of the regenerative energy saving of the MEA decarbonization system because of the integrationm of different heat pumps.About heat pump types on regenerative energy consumption of the MEA decarbonization system integrated heat pump,simulations show the MEA decarbonization system integrated the R600 two-stage closed heat pump is under a large rate of cooling savings and a low rate of heat savings in the regeneration process;and the rate of cooling savings of the MEA decarbonization system integrated tower top gas phase compression heat pump is equivalent to the rate of heat savings.In addition,the equal heat consumption and the cooling consumption of the former are respectively 15600.38kJ/CO2kg and 2882.69kJ/CO2kg in the regeneration process;the latter are respectively 12294.93kJ/CO2kg and 8859.11kJ/CO2kg.Compared with the standard MEA decarbonization system,the saving rates of the former are 7%and 78%,and the latter are 27%and 32%,respectively.About heat pump parameters on regenerative energy consumption of the MEA decarbonization system integrated heat pump,the effect of the heat pump parameters on the regenerative energy consumption of the MEA decarbonization system integrated closed heat pump is singular.The greater the specific heat of the refrigerant.the more obvious the effect of the total energy savings of the system and its regeneration.When conditions permit.the greater the value of inlet pressure of the cold stream in the exchanger and the evaporator,and the smaller the value of the flow rate of refrigerant,the low-pressure-stage flow ratio in the separator,the temperature of low-pressure-stage inlet stream in the restrictor and the temperature of stream in the low-pressure-stage reheater,the lower the regenerative energy consumption of the MEA decarburization system integrated closed heat pump.But the effect of the heat pump parameters on the regenerative energy consumption of the MEA decarbonization system integrated tower top gas phase compression heat pump,the influence of the heat pump parameters on the energy consumption is complex.And the regenerative energy consumption of the heat pump parameters can be roughly used to determine the optimization range of heat pump parameters.Based on heat pump types and heat pump parameters on the regeneration energy consumption of the MEA decarbonization system integrated heat pump,in terms of technical and economic performance analysis of the MEA decarbonization system integrated heat pump,the heat pump performance of the MEA decarbonization system integrated the R600 two-stage closed heat pump is better than the MEA decarbonization system integrated tower top gas phase compression heat pump,and the economic performance of the latter is better than the former.But the latter greatly enhances the complexity of the system and imposes stricter requirements on operational control.So the MEA decarbonization system integrated heat pump needs to be comprehensively considered multi-dimensional characteristics of the system,and choose the appropriate heat pump type and its heat pump parameters.