Method for preparing dichloroethane through direct chlorination by using dry gas

Abstract

The invention provides a method for preparing dichloroethane through direct chlorination by using dry gas, which includes the following steps that chlorine used as a raw material is fed into a pipeline reactor through a chlorine inlet nozzle, simultaneously dichloroethane mother liquor at the bottom of a bubble tower enters the pipeline reactor from a dichloroethane mother liquor inlet, the dry gas is fed into the pipeline reactor through a dry gas inlet nozzle, and dichloroethane is produced through reactions. The dichloroethane enters the bubble tower through a pipeline reactor outlet, steam on top of the bubble tower enters a condenser, tail gas is fed to following sections to be processed, condensed liquid of the dichloroethane enters a storage tank, partial dichloroethane enters the bubble tower through a pump to be recycled, partial dichloroethane is used as products, and the dichloroethane mother liquor at the bottom of the bubble tower is returned to the pipeline reactor to be recycled through a mother liquor pump. By means of the method, weight concentration of the obtained dichloroethane can reach more than 90%, ethylene conversion rate in the dry gas is larger than 95%, reaction selectivity of ethylene is larger than 98%, and the obtained dichloroethane can be used as a basic raw material for preparing polyvinyl chloride.

Description

technical field [0001] The present invention relates to the preparation method of dichloroethane. Background technique [0002] Ethylene dichloride (EDC) is the basic raw material for the production of polyvinyl chloride. About 95% of the world's EDC is used to produce VCM, and almost all VCM is used to produce PVC. Other uses of EDC are as chlorinated solvents such as trichlorethylene, ethylamine, vinylidene chloride, and trichloroethane, and also as an intermediate in the production of tetrachloroethylene and as a catalyst in the production of hexachlorophenoxymethane . [0003] Refining dry gas (referred to as dry gas, the same below) is the waste tail gas produced in the process of petroleum refining, the main components include C 2 h 4 、C 2 h 6 、CH 4 、H 2 、C 3 h 6 , CO, CO 2 、H 2 O and H 2 S and other components. So far, this part of petroleum resources is mainly used as fuel, and its main components such as ethylene, ethane, and hydrogen have not been eff...

AI Technical Summary

Problems solved by technology

However, the research object is only pure ethylene, and there is no discussion on other components in dry gas such as methane, ethane, hydrogen sulfide, etc.

In fact, in the pipeline reactor, due to the excellent mixing effect, the conversion rate of methane and ethane is already very considerable, which directly affects the purity of the product; while impurities such as hydrogen sulfide will cause the deactivation of the catalyst, greatly reducing the ethylene conversion rate

Due to the above reasons, the above-mentioned patented method cannot be directly used for the direct chlorination of refinery dry gas

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