流化床反应器的结构

流化床反应器是一种利用气体或液体通过颗粒状固体层而使固体颗粒处于悬浮运动状态,并进行气固相反应过程或液固相反应过程的反应器。

在用于气固系统时,又称沸腾床反应器。

Fluidized bed reactor is a kind of reactors that make use of gas or liquid through granular solid layer to make the solid particles in a state of suspension movement, and conduct reaction process of gas-solid or liquid-solid reactor process.When fluidized bed reactor is used in gas-solid system, it also called ebullient bed reactor.流化床反应器的结构有两种形式:①有固体物料连续进料和出料装置,用于固相加工过程或催化剂迅速失活的流体相加工过程。

②无固体物料连续进料和出料装置,用于固体颗粒性状在相当长时间内,不发生明显变化的反应过程。

The structure of the fluidized bed reactor has two forms:(1)It contains a continuous feeding and discharging device with solid materials which is used in solid phase processing procedure or fluid phase processing procedure where catalyst deactivates quickly.(2)It doesn't contain a continuous feeding and discharging device with solid materials which is used in the reaction process that the properties of solid particles have no obvious changes in a long time.流化床反应器的结构型式很多,但一般均由床层壳体、内部装置、换热装置、气固分离装置等组成。

There are a lot of the structural types of fluidized bedreactor.However, it generally consist of bed shell, internal device, the heat exchange device, gas-solid separation device, etc.(一)床层壳体。

床层壳体的作用是装载固体颗粒和保证流态化在所规定的范围内进行,这是最基本的作用。

(1) bed shell:The function of bed shell is to load solid particles and guarantee fluidization conduct within the prescribed scope,which is the most basic role.(二)内部装置。

内部装置包括气体分布器和内部构件,它们的作用主要是改善流化床的流化态。

(2) the internal device:Internal devices including gas distributor and internals, whose role is mainly to improve the fluidization states of fluidized bed.1、气体分布器气体分布器是流化床的主要构件之一。

它具有支承催化剂、均布气体、气体整流、稳定操作,强化传热传质等作用。

一般流化床气体分布器设计的要求是结构简单,阻力小,不漏料、不堵塞、制造方便等。

1, the gas distributorThe gas distributor is one of the most primary components of fluidized bed. It has function of supported catalyst, uniform gas, gas rectifier, stable operation, strengthen the heat and mass transfer, and so on. General fluidized bed gas distributor design’s requiremen t is simple structure, small resistance, no leakage, no jam, easy fabrication, etc.2、内部构件内部构件的作用在于破碎并限制气泡长大,减少气固体返混,改变气体固体颗粒在床中的停留时间分布。

流化床反应器的内部构件主要形式有管束(垂直管束和水平管束)和挡板(多孔挡板、导向挡板和挡网)。

对某一特定的反应过程,是否采用内部构件,取决于过程的特点。

一般如传质控制过程,为抑制气固体返混,减少颗粒的带出和需要对外进行热交换,应加内部构件。

管束管子的根数可由传热面的需要进行计算确定。

2, internals structureThe role of the internal components is to broke and limit the bubbles grow up, reduce the gas and solid back-mixing, change the residence time distribution of gas and solid particles in the bed. The main forms of fluidized bed reactor internals are the tube bundle (vertical and horizontal tube bundles) and damper (porous baffle, deflector and backstop). For a particular reaction process, whether fluidized bed reactor adopt the internal components depends on the characteristics of the process. Generally,taking an example of mass transfer control process, in order to inhibit the gas solid back-mixing, reduce the number of particles out of the bed and need external heatexchange, we should add internals. The number of tube bundle can be determined by the calculation of heat transfer surface.(三)换热装置流化床换热装置包括反应壳体器壁和浸没于床内的管束,其换热面积由过程本身的热效应大小决定。

(3) the heat exchange deviceFluidized bed heat exchanger device consists of tube bundle within the wall of reactor shell and immersed in a bed, whose area of heat exchange is determined by the heating effect of the process itself.(四)气固分离装置在流化过程中,小的颗粒总不免被流体带到反应器的上部或外部,尤其是在气速较大的操作状态下,被气体带走的固体颗粒的数量是很大的。

为了回收这部分颗粒,在流化床中心须有气固分离装置。

(4) gas-solid separation deviceIn the process of fluidization, the situation can’t be avoided all the time that small particles are taken to the top of the reactor or external by the fluid.Especially in the condition of operation that the gas velocity is larger, the number of solid particles which are taken away by the gas is very large. In order to recycle this portion of the particles,we must add solid separation device in the center of the fluidized bed.流化床气固分离装置主要有:1,旋风分离:旋风分离器主要依靠离心力的作用,使气流中的气体和固体颗粒分离。

2,在反应器上部连接一个扩大段,使气速降低,部分颗粒自由沉降分离。

可以安装一些使气流或固体颗粒改变流动方向的折流档板或其他快速分离装置。

Fluidized bed gas-solid separation device mainly has:1,cyclone separation: cyclone separator mainly relies on the effect of centrifugal force to make the air separation of gas and solid particles.2, connect an expanded section on the top of the reactor.It can reduce the gas speed quickly, and separate the part of granule in the way of free settling. Also,some baffle plate or other fast separation device which can change the flow direction of air or solid particles can be installed.。