| The development of integrated gasification Multi-generation system is an important technical and strategical choice to deal and revive an increasing rigorous situation of energy and enviroment in the world, specically in China. The integrated gasification Multi-generation system (IGMS) of coal gas, heat, and power (CHP) was presented in this dissertation. Two systemic flow sheets of IGMS with CHP both in Winter and in Summer were established with detailed description of mass flow, transfer and conversion of energy in subsystem of air separation, coal gasification, and combined cycle. Flow simulation of IGMS with CHP of Winter and Summer were performed with sequential module method. State parameter, procedure parameter, and performance parameter of both flow sheets were numerically obtained and quantificationally analyzed for two kinds of flow sheet.The resluts of Winter flow simulution show that the cause resulting in power output of vapor turbine on the low side is that pressure and temperature of exhaust steam of vapor turbine are higher for heat supply. The energy integrated utilization coefficient of system approach 76%. The thermal efficiency of combined cycle gets 38.48% and the energy integrated utilization coefficient of heat and power cogeneration (HPC) subsystem reaches 53.31% due to rational use of waste heat of exhaust gas to achieve step utilization of energy. For Summer flow sheet without heat supply and with lower pressure and temperature of exhaust steam of vapor turbine, the energy integrated utilization coefficient of system, thermal efficiency of combined cycle are 67% and 41.48%, respectively. The integrated utilization coefficient of HPC subsystem only gets 31.73% due to no use of most part heat of condensation of exhaust steam.The differences of state parameter, procedure parameter, and performance parameter of system between Winter flow sheet and Summer one were compared and analyzed. The analytical results show that differences of those parameter between Summer and Winter are mostly resulted from heat supply, pressure and temperature of inlet and outlet of vapor turbine with the same condition of design requirement and basic parameter.Based on the simulation of flow sheet, the influences of operation variable, such as total mass flow of air, mass flow of air separation, mass flow of coal, mass flow of vapor used to gasification, mass flow of coal gas used to combustion, mass flow of water used to heat supply in Winter, mass flow of water used to cooling in Summer, and mass flow of water as work fluid in vapor cycle, on state parameter, procedure parameter, and performance parameter of Winter and Summer were analyzed. The results show that upper to upstream the operation variable is, more obviously influence of operation variable on state parameter, procedure parameter, and performance parameter is. Operation variable of lower downstream has greater influence on state parameter, procedure parameter, and performance parameter whose location is downstream of the operation variable. Operation variable has direct influence on state parameter, procedure parameter, and performance parameter close to the operation variable. Operation variable has less influence on state parameter, procedure parameter, and performance parameter far away from the operation variable, taking coal gasification as example, operation variable upper gasification furnace has important influence on coal gasification, while operation variable lower gasification furnace has less influence on coal gasification.Based on flow sheet simulation and analysis of influence of operation variable on system performance, optimizations of IGMS with CHP in Winter and Summer with sequential quadratic programming method and under relative constraint conditions were implemented with maximum of energy integrated utilization coefficient of system, profit per day, thermal efficiency of combined cycle, and integrated utilization coefficient of HPC subsystem as optimum objective function. The optimum flow sheet with optimum decision variable such as flow fraction of air separation, total mass flow of air, mass flow of coal, flow fraction of coal gas used to combustion, mass flow of vapor used to gasification, mass flow of water of vapor cycle, mass flow of water used as heat supply in Winter, mass flow of water used as cooling water in Summer, and mass flow of hot water, were achieved to realize synchronized optimization of flow sheet and objective. The analysis of optimum decision variable, state parameter, procedure parameter, and performance parameter under different optimum objective functions were carried out and essential causes resulting in those difference were revealed.In Winter, optimization values of the energy integrated utilization coefficient of system, profit per day, thermal efficiency of combined cycle, and integrated utilization coefficient of HPC subsystem are 83.40%, 0.632 million RMB/day, 44.37%, and 64.52%, respectively. In Summer, optimization values of the energy integrated utilization coefficient of system, profit per day, thermal efficiency of combined cycle, and integrated utilization coefficient of HPC subsystem are 71.04%, 0.567 million RMB/day, 45.68%, and 36.88%, respectively.In final, differences of performance with different optimum objective function between Winter and Summer were compared and analyzed. The results show that energy integrated utilization coefficient of system and integrated utilization coefficient of HPC subsystem in Winter are higher than those in Summer due to heat supply realizing rational step utilization of energy. Thermal efficiency of vapor cycle and combined cycle in Summer are higher than those in Winter because of lower pressure and temperature of exhaust steam in Summer. Profit per day in Winter is higher than that in Summer when energy integrated utilization coefficient of system, profit per day, and integrated utilization coefficient of HPC subsystem are taken as optimum objective functions.
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