Research On Coordinated Control Of Coal-fired Power Station And Carbon Capture System

In response to the energy development strategy of "2030 carbon emissions peak,2060 carbon neutrality" proposed in the 14th Five-Year Plan,it is urgent to decarbonize coal-fired power stations.However,the carbon capture system of coal-fired power station is affected by the coupling characteristics of electric carbon,and the heat supply from the power generation side to the carbon capture side makes the thermal power unit run in the working mode of "carbon fixed power" for a long time,which greatly reduces the flexible operation ability of the unit.Moreover,the large-scale grid-connection of new energy makes the task of peak regulation of power grid more heavy,which puts forward higher requirements for the flexibility of generating units.This paper proposes a coordinated control strategy of electrocarbon decoupling for carbon capture power plants,which effectively improves the operational flexibility of generating units.The main research work and innovation of this paper are as follows:(1)The whole system model of coal-fired power station and carbon capture is established,and the calculation method of the dispatchable interval of electrocarbon coupling is given.Based on the mechanism modeling work of the traditional subcritical extraction steam generator set and each component unit of the carbon capture system,the dynamic models of extraction steam flow to generation power,extraction steam flow to carbon capture rate and flue gas flow to carbon capture rate were established based on the dynamic identification method,and the overall control model of carbon capture system of coal-fired power station was integrated.Based on the analysis of the coupling characteristics of the decarbonized power plant,a calculation method of the unit load scheduling interval under the decarbonized condition was established,and the main operating parameters in the process were verified by the open-loop step perturbation.(2)A coordinated control strategy of electric carbon with rapid response of pumping steam flow and self-recovery of energy is proposed to improve the capacity of the unit to change load quickly.The ratio of electricity and carbon energy supply is adjusted by controlling the opening of the extraction disc valve,and the fast response of the extraction steam flow to the load is utilized to realize the fast tracking of the load command of the power grid.The fluctuation of CO2 renewable energy caused by the change of the extraction steam flow is finally balanced by the fuel amount,which ensures the parameter stability and energy balance in the control process.(3)Taking a 300MW unit as an example,the control effect under different variable load rates is tested by simulation,and the effectiveness of the proposed strategy is verified.The verification results show that,on the one hand,the response speed of the system to load instruction changes is significantly faster than that of the traditional control strategy,the flexibility of the unit operation is improved,and the unit can realize the recovery of decarbonized pumping steam after the end of the response,ensuring the heat source demand of the carbon capture system.On the other hand,the decarbonized pumping steam flow rate and flue gas flow rate have different degrees of influence on the carbon capture rate.By decomposing the effects of the two,the follow-up characteristics of the carbon capture output to different parameters are obtained,and the response characteristics of the decarbonization efficiency in the process of rapid load changing of the unit are obtained.