Preparation method of anhydrous sodium sulfide for PPS

Abstract

The invention relates to a preparation method of anhydrous sodium sulfide for PPS. The preparation method of anhydrous sodium sulfide for PPS can be applied to industrial production operation. According to the preparation method of anhydrous sodium sulfide for PPS, a vacuum rake type drying machine is adopted to indirectly heat materials containing materials difficult to remove like crystal water; nitrogen is used for protecting the materials in the feeding phase and the discharging phase, vacuum operation is carried out on the materials in the drying process, and therefore oxidation of the materials is avoided; in the drying process, a multi-section temperature rise (80-170 DEG C) drying method is adopted, and the materials are prevented from melting and bonding the wall of devices; in an offgas treatment phase, moisture and harmful gas are effectively processed through the washing function of a washing tower, and therefore a series of problems produced when an existing preparation method of anhydrous sodium sulfide for PPS is used are solved.

Description

technical field [0001] The invention relates to the technical field of vacuum drying, which is a drying method for preparing anhydrous sodium sulfide. Background technique [0002] The sodium sulfide material required for the production of PPS not only has a moisture content of less than 1%, but also requires high purity, and its price is relatively expensive. Therefore, it is of great significance to develop a more convenient method for industrialized production of anhydrous sodium sulfide. [0003] The production technology of existing anhydrous sodium sulfide mainly exists the following problems: [0004] (1) Sodium sulfide materials mostly exist in the form of crystal water. For materials containing different crystal water, their melting points are different. Therefore, during the drying process, the material is very easy to melt, resulting in the bonding of the material to the equipment. [0005] (2) The sodium sulfide material is easily oxidized in the air to generat...

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Problems solved by technology

[0007] In order to solve the problems that sodium sulfide materials are prone to oxidation, melting and tail gas treatment

In this method, nitrogen is introduced into the process of feeding and unloading for protection, and drying operation is carried out under vacuum to achieve the effect of isolating oxygen. Through the method of five-stage heating, the temperature range is 80~170°C, which can effectively solve the problem. The problem of melting and agglomeration of sodium sulfide materials, as well as the emission of exhaust gas, can also be washed by a scrubber to remove toxic gases

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