Numerical Simulation Of Precalciner And Bypass System In The Cement Production

Cement production is the basic industry for national economy development.It is also a high-pollution,high-energy-consumption industry.According to the problem of sustainable development,“low carbon energy saving,intelligent production,transformation and upgrading” is the tendency of cement industry development.Applying the advance science and technology to the traditional industry development and promotion,is good to realize the cement industry modernization and improve international competitiveness.Along with the rapid development of CFD technology,CFD technology has apply widely into the engineering field involving flow,heat transfer,mass transfer,combustion,and chemical reaction.In cement pre-calcination system,the flow inside cyclone is a typical gas-solid two-phase flow;calciner is a typical reactor involving flow,combustion and chemical reaction.CFD technology is applied to research the method to simulate the two-phase flow inside the cement pre-calcination system,to research the complex law of flow and mechanism of physical and chemical process.These results can help to guide the cement production process and equipment design.The object of research is 6000 TPDsingle series cyclones system,calciner and by-pass system.Because that the volume fraction somewhere inside the cyclone and calciner is greater than 10%,so the Eulerian two fluid model is adopt to the flow simulation.Through the coupling the two-phase interaction,the mass,momentum and energy equations are resolved.The simulation result coincides with the engineering data.It invalids that Eulerian two fluid model is suitable to the cyclone and calciner.Because this model resolves kinds of information comprehensively and completely,so it will reach to more accurate result.Component transport models adopted to simulate methane combustion inside calciner.Because of the turbulent flow,eddy-dissipation model is used to compute the combustion reaction rate and the temperature field inside calciner is simulated.Based on the result of combustion simulation,the raw material calcination model is set to research the calcination mechanism and compute calcination rate inside calciner.The results coincide with the engineering data well.According to the bypass system,based on the simulation of the flow of kiln end smoke chamber,the by-pass location is set by compute the particle concentration.The influence of incline angle on the flow,particle concentration and pressure loss is compared.For the by-pass system,the influence of the ration of hot-cold gas,the length of heat-exchange pipe and the length of volute structure is researched by the simulation.The results supplied the theoretical basis for by-pass system design.