Ammonia-soda process mother liquid distillation tower scaring-proof method

Abstract

A scab resistance method of a mother liquor distillation tower by an ammonia-soda process includes the distillation tower and a preliming tank. After the distillation tower is opened and the liquid flows down, according to the proportion of the distillation tower mother liquor steam amount between 1 percent and 2 percent, a thin liquor containing CO2 and NH3 is added continuously into the preliming tank to react chemically with a lime milk Ca (OH) 2 in the preliming tank under the condition that the mother liquor is preheated to 95 DEG C. An impurity CaSO4 crystal is produced in the preliming tank. At the same time, a scab elimination agent is added to a preheated mother liquor pipe and enters into the preliming tank as the preheated mother liquor. The liquid flows from the preliming tank into the distillation tower. The preheated mother liquor is SO4<2->:0.72ti, CO2:1.8ti and the temperature is 95 DEG C. the thin liquor is NH3: 170ti, CO2: 48ti and the temperature is 60 DEG C. By using the present invention, the distillation tower has little scab and the operation of the tower is optimized. The present invention has the advantages of low steam consumption amount, short time of stopping the tower to clean, low work intension and reduced expenses.

Description

Technical field: [0001] The invention relates to the technical field of anti-scarring of distillation towers in the chemical industry, in particular to a method for preventing scarring of ammonia-alkali mother liquor distillation towers used in ammonia-soda method mother liquor distillation tower systems. Background technique [0002] Calcium sulfate scabbing in the mother liquor distillation tower is the most troublesome technical problem in the world's ammonia-soda alkali production industry. The sulfate radicals that enter the mother liquor with the raw salt are in the form of calcium sulfate in the distillation system (including pre-ash buckets, distillation towers and waste liquid pipelines). Crystals form rapidly and deposit on the channel. In order to reduce the speed of scarring, some manufacturers increase the volume of the pre-ash bucket to eliminate the supersaturation of calcium sulfate as much as possible, and some use high-vacuum distillation to reduce the temp...

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