Study On Spontaneous Combustion Characteristics Of Powdered Active Coke And Process Flow Of Desulfurization System

Active coke flue gas desulfurization process has attracted wide attention due to its high desulfurization efficiency and easy resource utilization.In order to realize coking,desulfurization and utilization of sulphur resources at the same time,Shandong University put forward a one-step process for in-situ preparation of powdered activated coke from power plant and completed pilot test.At present,the subject team has made full research on the preparation process of powdered activated coke,the desulfurization process of powdered activated coke in fluidized bed and the process of carbothermal reduction of SO₂ to produce sulfur,while the characteristics of flue gas desulfurization system combined with the above process are still unclear.In addition,the research team completed the research on the thermal properties of activated powder coke prepared in one step and the heat and mass transfer characteristics of activated powder coke in dense phase flow,while the research on the heat release characteristics and self-ignition characteristics of powder coke in air was lacking.In this paper,the low temperature oxidation characteristics of powder coke in air and the spontaneous combustion characteristics of powder coke in coke bin are studied based on experimental and simulation methods,and the process flow field of in-situ preparation of powder coke flue gas desulfurization system in power plant is analyzed.Natural oxidation characteristics of coke in air have been studied.Firstly,TG-FITR was used to analyze the gas products of coke samples oxidized in air.Then,the rate of CO and CO₂ formation of coke samples under different temperature and oxygen concentration was quantitatively analyzed by temperature programmed experiment.Combining the basic theory of reaction kinetics with Arrhenius model,the function relationship between CO and CO₂ generation rate and temperature and oxygen concentration was fitted.The spontaneous combustion characteristics of coke in coke bin are simulated.The source terms of fluid continuity equation,energy equation and component equation were changed by user-defined function（UDF）,and the temperature field,concentration field and flow field of fluid in coke bin were solved by coupling.The simulation results show that it is difficult for the coke to spontaneously ignite when the initial temperature is lower than 150℃.The higher the initial temperature,the closer the ignition point to the air inlet.The process of in-situ preparation of powder coke flue gas desulfurization system in power plant is studied.This paper establishes a mathematical model for the in-situ rapid preparation of powdered activated coke flue gas desulfurization system in380MW power plant,calculates and analyses the influence of key operating parameters such as adsorption temperature,regeneration temperature,coal consumption,excess air ratio and regeneration rate on the system operation,which provides guidance for the engineering design of desulfurization system.