Method for rectifying thionyl chloride

Abstract

The invention relates to a method for rectifying thionyl chloride. According to the invention, sulfur monochloride flowing down to the bottom of a rectifying tower enters a reboiler at a large flow through a vertical submerged circulating pump for heating and forced circulation, and a gas-liquid (mainly a liquid phase) mixture after heat exchange and temperature rise ascends to enter a stripping section at the lower part of the rectifying tower to serve as a heat source for stripping crude thionyl chloride, so the stripping section of the rectifying tower is ensured to have enough heat; the sulfur monochloride in the reboiler is forced to circulate by pumping, and the heating temperature of the sulfur monochloride is reduced to increase circulating flow, so the sulfur monochloride carries heat necessary for the steam in the rectifying tower mainly in a liquid form; the circulating temperature of the sulfur monochloride is reduced, design requirements on equipment and materials are reduced, the rising sulfur monochloride steam in the rectifying tower is greatly reduced, the reflux circulating demand amount of a finished thionyl chloride product is reduced, the use amount of flaky sulfur for reduction is reduced, the possibility of blockage of the rectifying tower is reduced, and the quality of the finished thionyl chloride product is improved; and a vertical submerged pump is adopted as a circulating pump, so leakage of a process medium is avoided.

Description

technical field [0001] The invention belongs to the technical field of chemical industry and relates to a rectification method of thionyl chloride. Background technique [0002] Thionyl chloride is also called thionyl chloride, and its molecular formula is SOCL 2 , the product produced by its synthesis device is a crude product, containing thionyl chloride (boiling point 78.8°C), sulfur monochloride (also known as disulfur dichloride, boiling point 138°C), sulfur dichloride (boiling point 59.6°C), Rectification is required to obtain qualified products. [0003] Such as figure 1 Shown, existing sulfur oxychloride rectification device is by feed pump, rectification tower, condenser, sulfur reduction tower, sulfur oxychloride storage tank, accepting tank (can be replaced by rectification tower bottom section), reboiler, It consists of sulfur monochloride pump, sulfur monochloride storage tank and other equipment. [0004] Crude thionyl chloride is pumped into the middle of ...

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Problems solved by technology

[0006] Because the heat required for stripping thionyl chloride is mainly carried by sulfur monochloride vapor with a high boiling point, the existing rectification process requires a higher reboil temperature, which leads to an increase in the circulation of thionyl chloride in the rectification section, increasing energy consumption

At the same time, too much non-thionyl chloride gas in the rectification section rises to the top of the column, which can adversely affect the crucial color of the finished product

Moreover, too much sulfur monochloride gas enters the sulfur reduction tank at the top of the device, which will melt sulfur and increase consumption, and it is easy to block the rectification tower

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