Simulation Study On The Fluidized Bed Two-Step Gasification Process Of Coal And Refuse Derived Fuels

The amount of urban domestic waste in my country was increasing with the continuous improvement of social modernization and the continuous acceleration of the urbanization process.The traditional three treatment processes of landfill,composting and incineration couldn’t meet the current requirements of reduction,harmlessness and recycling.Due to the requirement of resource utilization,in recent years,many researchers had conducted effective explorations on the pyrolysis and gasification process of municipal solid waste.In this paper,the high calorific value composition coming from municipal solid waste was selected to prepare refuse-derived fuel（RDF）,and it was used together with coal as the raw material for a new type of gasification process named by the fluidized bed two-step Gasification process to explore gasification characteristics.On the one hand,the gasification process could further avoid the contact of N,S,Cl elements in the waste with the air O elements in air,so it could avoid the generation of dioxins theoretically and reduce the generation of normal pollutant at the same time.On the other hand,the temperature of the gasification process could be controlled between 850～1050℃,which greatly promoted the generation of volatile gas and promoted thr degree of energy utilization.The research process determine the relation of the gas production characteristics and technical parameters like the gasification temperature and the ratio of water vapor to RDF by the experiment and simulation.The specific research content is as follows:Firstly,this paper conducted the gasification feasibility analysis of the five high-calorific value components of municipal solid waste:paper,plastic,rubber,plants and branches according to the basic research methods of industry,element,thermogravimetry and ash melting point analysis to determine that the suitable temperature for gasification research should between 800℃and 1050℃.Secondly,the preliminary experimental research was conducted based on the two-step gasification process of coal and refuse-derived fuel.It found that the appropriate mass input ratio of coal to RDF during operation was determined to be 1/4.,the propotions of H₂and CO increased with the increase of temperature and the propotions of CH₄and CO₂decreased with the increase of temperature.Finally,ASPEN PLUS software was used to build the thermodynamic and kinetic gasification model of the two-step gasification process.On the basis of verifying the accuracy of the model,this paper specifically explored the influence of the gasification process temperature and the ratio of water vapor to RDF in the gasification stage on the process gasification characteristics.This prediction data could make up for the lack of experimental data to provide effective theoretical guidance for the actual production process and save research costs greatly.The research of this subject has effectively proved the feasibility of the fluidized bed two-step gasification process of coal and refuse-derived fuels.The research methods and modeling concepts of the built of the thermodynamics and kinetic ASPEN PLUS model could also provide some theoretical guidance for other scholars in this field to make gasification researches.