Built-in electric heating type fluidized bed cracking reactor

Abstract

The built-in heating fluidized bed cracking reactor consists of fluidized bed body, fluidized bed layer, built-in electric heater, cyclonic separator and other parts. The present invention has built-in electric heater for heating and gas distributor to separate the fluidized bed into two parts of fixed bed layer and fluidized bed layer. The fluidized bed with excellent heat conducting and mixing characteristic is utilized to make gas heated fast to reach the required reaction temperature for high temperature and short retention time of cracking operation, high conversion rate and selectivity of cracking reaction, and raised heat efficiency of the reactor. In addition, fluidized the particle can avoid coking effectively to prolong the operation period of the reactor.

Description

technical field [0001] The invention relates to a fluidized bed reactor, in particular to a built-in electrically heated fluidized bed reactor for cracking reaction, which belongs to the technical field of chemical equipment. Background technique [0002] Pyrolysis reaction is a reaction process in which organic matter decomposes under high temperature and air isolation conditions, and is widely used in chemical production. The most typical thermal cracking reaction is the production of ethylene, and other processes such as the production of ketene from acetic acid cracking, and the production of vinyl chloride from dichloroethane cracking. The thermal cracking reaction generally has the following characteristics: 1) high reaction temperature; 2) strong heat absorption; 3) short residence time is required; 4) generally a cascade reaction, the product is an intermediate product, and coking is accompanied by coking during the reaction process. Therefore, in order to achieve a...

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Problems solved by technology

This external heating method has the following disadvantages: First, the cracking temperature is limited by the tube wall temperature, and the tube wall temperature is limited by the heat resistance of the metal material

In order to reduce this heat transfer resistance, a higher flow rate in the tube is required. When the cracking time is fixed, a longer furnace tube is required, and the furnace becomes slender, and the heat dissipation to the environment is greater, and the thermal efficiency is lower.

Second, in order to increase the area of ​​heat transfer from the tube wall to the fluid in the tube, to reduce the heat load per unit area, thereby reducing the heat transfer temperature difference ΔT, so that the fluid in the tube reaches a higher cracking temperature, the reactor has to adopt multiple sets of parallel Small-diameter furnace tubes make it difficult to clean coke in this reactor; third, the temperature distribution is uneven, and there is an obvious temperature distribution in the axial direction. When the tube diameter is large, there is also an obvious radial distribution, so the temperature Sensitive reaction system, its application is limited

However, for the small-scale cracking process that uses electric heating and is prone to coking, the disadvantages of the above-mentioned tube furnace reactor are very prominent.

On the one hand, the reactor is designed in a slender shape, which is easy to dissipate heat, has low thermal efficiency, and consumes a lot of power

On the other hand, due to the problem of coking, the reactor is often shut down for treatment, which increases the production cost

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