Simulation on the Process of Oil Shale Retort and Its Semi-coke Combustion
|School||Tohoku Electric Power University|
|Keywords||oil shale retort semi-coke combustion simulation|
Process of oil shale retort and its semi-coke combustion was simulated usingAspen Plus. Simulation of retort was based on the model of retort furnace with acapacity of300ton oil shale per day using gas as heat carrier，and simulate resultswere analyzed. The combustion of semi-coke from retort furnace with gas heat carrierwas simulated，and analysis of outlet products was made，which was affected bymany factors，such as inlet air amount，inlet stream temperature，etc.A model of oil shale retort furnace with gas heat carrier was developed usingAspen Plus，which mainly integrated the process operations of drying/preheating andpyrolisis of oil shale feedstock. Components in oil shale feedstock were divided intomoisture，organic substance，and minerals，which were defined as conventionalstream， non-conventional stream and conventional inertia stream respectively.According to the mechanism of oil shale pyrolisis and kinetic equation of overall firstreaction，the mass of organic matter and its pyrolysis products including shale oil，pyrolysis gases and semi-coke have been calculated and analyzed at normal operatingtemperature of the retort. They were also calculated and analyzed at differenttemperatures. The simulation results agreed well with design and operationparameters of the retort，and it was convenient to predict the mass of pyrolisisproducts at different temperatures.When simulation of semi-coke combustion was done，semi-coke was defined asnon-convertional substance at first，and then the non-conventional substance wasdecomposed into conventional substance，and then the conventional substance reactswith oxygen. The combustion products were calculated according to method of Gibbsfree energy minimization. The amount of oxygen required by simulation wasconsistent with oxygen consumption calculated by the empirical formula. Andanalysis was made to predict temperature，components and density of the combustion products under different circumstances，such as different amount of oxygen anddifferent dehydration.