Experiment And Simulation Of CS₂ Production By Fixed Bed

As an important industrial raw material,the conventional production process of carbon disulfide has two kinds: semi coke method and natural gas method.Although natural gas method has the advantages of continuous production,high degree of automation and convenient centralized control,it is also restricted by the treatment of hydrogen sulfide tail gas and cost,which leads to the complex process and limited site selection,so the process is relatively simple,the cost is low,the cost of raw materials is low,and the widely source semi coke method is unique.Advantages,but production capacity,environmental protection and other problems are important reasons for restricting the development of the process.Therefore,it is necessary to analyze the process of semi coke process and seek improvement.The core sulfur and semi coke reactor in this process needs to be improved in order to further improve the sulfur utilization rate and reduce the output of byproducts.Therefore,sulfur and half of the product are needed.The process of coke reaction is well understood.Based on this,this paper uses a self-made small fixed bed experimental device to analyze the reaction characteristics and apparent reaction kinetics of sulfur and semi coke.The results show that the reaction of carbon and sulfur is a first-order reaction at the temperature of 800~920?.The reaction rate constant and the temperature are in accordance with the Arrhenius equation.In the same condition,the higher the temperature,the higher the sulfur conversion rate;the difference in the semi coke itself has little effect on the rate of the reaction rate of the carbon and sulfur,and the reaction performance of the sulfur recovery is obviously reduced after reutilization.At last,the semi coke before and after the reaction was characterized.The pore volume and specific surface area were measured by the method of nitrogen adsorption and desorption.The percentage of the element content on the surface of the semi coke was measured by the electron microscope on the surface of the semi coke.According to the results,the specific surface area of the reaction char decreased significantly,and the surface sulfur content of the char increased significantly.Based on the experimental kinetic parameters,the reaction process in a fixed bed reactor was simulated,analyzed and optimized.Taking the current industrial fixed bed reactor as the simulation object,based on the conservation law,combining with the macroscopic kinetics of the carbon sulfur reaction in this paper,a theoretical mathematical model is established to describe the momentum transfer,heat transfer and mass transfer process and reaction coupling in the reactor.The model is based on the porous medium.The parameters such as viscosity,diffusion coefficient and thermal conductivity are calculated by document acquisition model,and the COMSOL numerical software based on finite element method is used to solve the established mathematical model to obtain the distribution of pressure,temperature and product concentration in the reactor,and the model is combined with industrial data to model the model.On this basis,the influence of inlet mass flow rate,inlet temperature,wall temperature and voidage on sulfur conversion rate is further analyzed.The results showed that the inlet mass flow rate and wall temperature had great influence on sulfur conversion rate,while inlet temperature and porosity had little effect on sulfur conversion rate.At last,the structure of the reactor is optimized by the simulation results.The gas distribution plate and the heat transfer area of the reactor can be increased further.This study can provide some theoretical guidance for further research and optimization of reactors and lay a solid foundation for further improvement.