Screening Of Chemical Looping Combustion In Oxygen Carriers

Chemical looping combustion is clean and efficient generation of combustiontechnology. It releases energy by flameless reaction which does not directly contact thefuel and air, which eradicates the generation of NOx, and CO2can be directly recoveredby condensation trap way, which does not require additional energy consumption.Theoxygen carrier of chemical looping combustion not only transfers heat, but alsotransfers oxygen, It is the key factor of chain combustion technology. Screening andoptimization of the oxygen-carrying agent, the reaction conditions were studied,developed for different fuels suitable oxygen-carrying agent, chemical loopingcombustion technology enables higher combustion efficiency.In this paper, the thermodynamics of all types of carrying oxygen reductionreaction agent and methane were analyzed firstly, which preferably selected theexcellent oxygen carriers of thermodynamic properties; Then I used the Aspen Plussoftware to simulate the oxygen carrying agent selected and the model has beenvalidated. Through the calculation of chemical equilibrium in the reactor, I analyzed theeffects of molar ratio of reactants, temperature and pressure on the reduction reactoroutlet mole fraction, and optimize the reaction conditions of oxygen carrier.The research results show: the metal based oxygen carrier of thermodynamicproperties are Nickel and Ferrous oxygen carrier, and CaSO4is the best among the nonmetal oxygen carriers; In the reduction reactor of NiO-CH4chemical chain combustion,the combustion process changed with the molar ratio of the reactants is divided intothree stages: If X≤1, fuel combustion is mainly methane reforming reaction; If1X≤4, fuel combustion is mainly oxidation reduction reaction, and the methane reformingreaction decreases; If X4，all the products are CO2and H2O, so the best reactant molarratio is X=4, the reaction temperature is1000K-1100K, and the operating pressureshould not be greater than8MPa. In the reduction reactor of Fe2O3-CH4chemical chaincombustion, the combustion process changed with the molar ratio of the reactants isalso divided into three stages and the best reactant molar ratio is X=12, the reactiontemperature is1000K-1150K, and the operating pressure should not be greater than5MPa. The simulation study on the reduction reaction of CaSO4oxygen carrier showsthat in the reduction reactor of CaSO4-CH4chemical chain combustion, the best reactantmolar ratio is X=1, the reaction temperature is1000K, and the proper operating pressureis atmospheric pressure.