Numerical Simulation Of Chemical-looping Gasification Process Of Phosphogypsum And Lignite

The greenhouse effect has become a global hotspot,and chemical looping combustion technology?CLC?is a promising new combustion technology that can achieve CO2 separation,NOx-free generation and no energy loss.The current research of this technology mainly focuses on the design and operation of the reactor,the performance study of the oxygen carrier and the numerical simulation of the flow and reaction.The chemical looping gasification technology is based on the development of chemical looping combustion technology,and the synthesis gas mainly composed of CO and H₂ is prepared by the reaction between coal,oxygen carrier and water vapor.Phosphogypsum is an industrial solid waste with large discharge and accumulation,which seriously pollutes the environment.Because its main component is CaSO₄,it can be used as an oxygen carrier to make full use of it;lignite is easily weathered and difficult to store and transport.The mode of utilization is mainly direct combustion,low energy efficiency and environmental pollution.It is used as a solid fuel in the chemical chain gasification process,avoiding direct contact with air,no NOx production and full utilization of energy.In this paper,the fuel reactor of the hot fluidized bed is selected as the research object.Based on the two-fluid model and coupled with mass transfer heat transfer and chemical reaction,the effects of temperature,pressure and gas velocity on the fluidization process are studied by numerical simulation.The reduction kinetics model of the overall reaction of phosphogypsum,lignite and water vapor and the kinetic parameters required for numerical simulation were obtained by thermal analysis experiments based on the shrinkage model.The gas-solid phase in the cold fluidized bed and the hot fluidized bed were respectively determined.The volume fraction distribution,velocity distribution and material distribution in the bed were simulated.The feasibility of the simulation method and model was verified by the axial pressure gradient distribution in the bed and the yield of CO and CO₂ after the reaction.Based on the cold fluidization process,the heat was The multi-component and multi-stage chemical reactions were considered in the fluidization simulation,and the characteristics of the gas-solid flow and composition distribution in the reactor with the conditions were simulated.On this basis,the influence of some important parameters such as temperature,pressure and gas velocity on the fluidization process in the fuel reactor is explained,and the experiment is supplemented and expanded to provide a theoretical basis for large-scale industrial operation.