复合床氧热法电石反应器模型化研究

发布时间：2018-03-10 00:15

本文选题：电石反应器　切入点：耐火砖　出处：《北京化工大学》2015年硕士论文　论文类型：学位论文

【摘要】：我国的能源结构是多煤、贫油、少气,然而我国大量的煤炭直接燃烧造成了能源浪费,也产生了环境污染。而煤可以合成化工的重要原料电石,通过电石与水反应,可以生成重要的有机原料乙炔,因此煤制取电石有着重要的意义。然而传统电热法制电石反应器存在许多不足,刘振宇等提出了新型的氧热法制电石复合床反应器。本文针对新型的复合床反应器开展了模型化设计研究,也即,采用冷模实验方法设计了一种搅拌式的复合床反应器固体布料器,并考察了影响颗粒通过布料器的质量通量的因素；同时针对反应器熔池区设计,运用数值模拟方法考察开车过程、正常工况以及出料过程等工况下熔池的传热特性,据此提出熔池区耐火结构的优化设计方案。首先,设计了一种新型布料器,并考察了桨叶类型、颗粒类型、分布板类型、床层高度、桨转速、桨叶到分布板距离等六个因素对颗粒下落质量通量的影响。结果表明：(1)随着床层高度增加、桨叶转速增加,颗粒下落质量通量均呈增加趋势。(2)随着桨叶到分布板距离增加,颗粒下落质量通量呈指数降低。(3)对于颗粒下落体积通量：玻璃球的远大于催化剂颗粒的。(4)对于颗粒下落质量通量：采用平桨叶时的远大于下压式桨叶时的；采用27孔分布板时的大于12孔分布板时的。(5)据此得到优选的设计条件为：采用27孔分布板,平桨叶且桨叶到分布板距离约为颗粒直径的2倍。其次,设计了熔池区的耐火保温结构并针对熔池高度一定的情况下,对熔池传热与保温性能进行了研究。数值模拟结果表明：(1)初步设计的粘土质隔热耐火砖处有烧坏的危险,建议将此部分砖改为铬刚玉砖等。(2)电石反应3h后,可以考虑出料。(3)开车前应预热在15h以上。最后,针对反应器熔池区出料工况进行了考察,运用动网格技术模拟出料过程。结果表明：(1)反应器出口处耐火材料选取为白刚玉砖的厚度为0.1m,可以保证刚玉砖下层的耐火砖不被烧坏。(2)反应器出料20min的过程中,熔池区的稳定性较好,响应时间较慢。(3)设计反应器时,应多设几个出口。
[Abstract]:The energy structure of our country is rich in coal, lean oil and little gas. However, the direct combustion of a large amount of coal in our country causes energy waste and also produces environmental pollution. Coal can synthesize calcium carbide, an important raw material of chemical industry, and react with water through calcium carbide. Acetylene, an important organic raw material, can be produced, so it is of great significance to produce calcium carbide from coal. However, there are many shortcomings in the traditional electrothermal calcium carbide reactor. Liu Zhenyu and others have proposed a new type of oxy-thermal calcium carbide compound bed reactor. In this paper, a model design study has been carried out for a new type of compound bed reactor, that is, In this paper, a kind of solid distributor of agitated compound bed reactor is designed by cold model experiment, and the factors influencing the mass flux of particles passing through the reactor are investigated, and the design of the reactor molten pool is also carried out. The heat transfer characteristics of molten pool under starting, normal and discharging conditions were investigated by numerical simulation method. Based on this, the optimum design scheme of refractory structure in molten pool region was put forward. Firstly, a new type of distributor was designed. The effects of six factors, such as blade type, particle type, distribution plate type, bed height, propeller speed and distance from blade to distribution plate, on mass flux of particles falling are investigated. The results show that the rotor speed increases with the increase of bed height. The mass flux of particles dropped increased with the increase of the distance from the blade to the distribution plate. The drop mass flux of the particles decreased exponentially.) for the falling volume flux of the particles: the volume flux of the glass sphere was much larger than that of the catalyst particle.) for the falling mass flux of the particles, the flux of the falling mass of the particles was much larger when the flat blade was used than that of the lower pressure blade; The optimum design conditions are as follows: with the 27 hole distribution plate, the distance between the blade and the distribution plate is about 2 times the diameter of the particle, and the optimum design conditions are as follows: using the 27 hole distribution plate, the distance from the blade to the distribution plate is about 2 times that of the particle diameter. The refractory insulation structure in the molten pool area is designed and the heat transfer and thermal insulation properties of the molten pool are studied under the condition of the molten pool height. The numerical simulation results show that the primary design of the clay insulating refractory brick has the danger of burning out. It is suggested that this part of the brick should be preheated for more than 15 hours before starting up after 3 h reaction with chrome corundum brick and so on. Finally, the discharge condition of the reactor molten pool area was investigated. The dynamic grid technique was used to simulate the discharging process. The results showed that the refractory at the outlet of the reactor was chosen as white corundum brick with a thickness of 0.1 m, which could ensure that the refractory brick in the lower layer of corundum brick would not be burned out for 20 minutes. A few more exits should be set up when the reactor is designed with better stability and slower response time.
【学位授予单位】：北京化工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ161;TQ052

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