Simulation And Optimization Of Coal Gasification Chemical Looping Combustion Combined Cycle System

It is a hotspot today that how to clean and effective utilization of coal, which isan important energy resource. Poly-generation, which based on IGCC and put forwardat the end of last century, is a consensus for high efficient, clean and economic use ofcoal. Advanced integrated system, which has a broad application prospect, realizedthe optimization of chemical energy, heat and electricity integration. It can alsoimprove the energy utilization efficiency and satisfies the requirement of zeropollutant discharge. As a kind of energy cascade utilization technology, chemicallooping combustion is treated as the breakthrough point to solve the problem ofenergy shortage and environmental pollution, it can reduce the waste emissions andrealize the release of energy.In this paper, coal gasification-chemical looping combustion combined cyclesystem is analyzed and simulated by Aspen Plus. After the simulation, the initialefficiency of circulatory system is generated. On the other hand, a multi-objectiveoptimization algorithm, non-dominated sorting evolution strategy (NSES) iscompared with a traditional algorithm (NSGA-II) in solution of test function. Theresults show the effectiveness and superiority of NSES. On this basis, the coalgasification unit and air separation unit is combined with NSES respectively to themulti-objective optimization.In coal gasification unit, the ratio of oxygen/coal, ratio of water/coal andgasification pressure are selected as optimization variables; the maximize yield ofeffective gases and maximize cold gas efficiency are treated as goals. In air separationunit, the feed rate of air and the high pressure tower outlet flow rate are selected asoptimization variables; The maximize yield of oxygen and minimize of the unit’senergy consumption are treated as goals, on the other hand, the nitrogen content ofnitrogen flow and oxygen content of oxygen flow must be stipulated in Aspen Plus.After optimization, the optimized efficiency of circulatory system is generated bysubstitute the optimized operating variables into simulation. The results show that theoptimization of two units has improvement of the circulatory system’s efficiency, butthe multi-objective of coal gasification unit’s optimization is more effective.