Research On Modeling Of The Combined-Bed Reactor For Oxygen-Thermal Calcium Carbide Production

The energy structure of China is more coal, little oil and less gas, but direct combustion of coal causes a waste of energy and also gives rise to environmental pollution. However, calcium carbide, which is an important chemical raw material, can be synthesized through coal, and, moreover, acetylene, which is an important organic raw material, can be generated by reaction of calcium carbide and water, so calcium carbide generated through coal has great significance. But traditional calcium carbide reactors of electricity-thermal method have many deficiencies. Therefore, Liu Zhen Yu creatively puts forward the new composite-bed calcium carbide reactor of oxygen-thermal method. This paper presents a modeling study for the design of the composite-bed reactor, i.e., a new design scheme for the distributor used for solid distribution is proposed, which is an important component of the composite-bed reactor, and also influencing factors of mass flux of particles through the distributor are investigated by experiment. It provides the basis for the design of the actual distributor in the reactor. At the same time, temperature field of molten pool in the reactor is investigated through simulation.Refractory performance and the size of refractory bricks, discharging time of molten pool and design of discharge port are discussed.Firstly, we design a new distributor and evaluate influence of 6 factors, which are blade type, particle type, distributing plate type, bed height, rotation speeds of paddles and the height between paddles and distributing plate on particle mass flux through distributors by experiment, The experimental results show that:mass fluxes increase with increasing the bed height and the rotation speed of blade. With an increase in distance between the blade and distribution, the mass flux decreases sharply. Compared to catalyst particles, glass beads exhibit a large mass flux. Using a flat blade rather than an oblique one, and a distributing plate with more holes, both lead to far greater mass fluxes. The optimal design of distributor is the flat blade, the distance between the blade and distribution is twice that of the diameter of particles and the distributing plate with more holes.Secondly, heat transfer in the molten pool and properties of refractory bricks are studied at a certain height of molten pool.Numerical simulation results show that:(1) the refractoriness of the clay refractory bricks is lower than the actual temperatures simulated, so there is a risk. The suggestion is: clay refractory bricks should be replaced by refractory bricks having high refractoriness.(2) Solidification of calcium carbide will not be a problem for discharging after 3h.(3)Preheating time before discharging should be longer than 15h.Finally, we use dynamic mesh technique to simulate discharging process. The results show that:(1)When the height of white corundum bricks, which are refractory material of reactor outlet, is 0.1m, it will ensure other refractory bricks, which are below white corundum bricks, don’t burn out. (2) There is little change in overall temperature of refractory bricks in the process of discharging, so it suggests that the stability of temperature system of molten pool area is good, and responding time is slow. (3)More outlets should be designed for the reactor.