Technical method and equipment for co-production of hexamethylene tetramine from tripolycyanamide tail gas

Abstract

The invention relates to a technical method and equipment for co-production of hexamethylene tetramine from tripolycyanamide tail gas, and belongs to the technical field of chemical production. To solve the problems that the conventional relevant products to tripolycyanamide tail gas utilization are excess in production capacity and sluggish in market, the technical method and equipment for co-production of hexamethylene tetramine through tripolycyanamide tail gas are provided; the technical scheme comprises the following steps: step one, tail gas storage; step two: heat preservation conveying; step three: preliminary removal of impurities; step four: secondary removal of impurities; step five: ammonolysis reaction; step six: performing crystallization to form products. The method is applied to the co-production of a novel product hexamethylene tetramine from tripolycyanamide tail gas.

Description

Technical field [0001] The invention relates to a process method and equipment for co-producing hexamethylenetetramine from melamine tail gas, which belongs to the technical field of chemical production, and specifically relates to the utilization of melamine tail gas. Background technique [0002] my country's melamine co-production of urea, co-production of ammonium nitrate, co-production of soda ash, and co-production of ammonium bicarbonate. When the production capacity of melamine is too large, problems such as difficulty in material balance and difficulty in achieving gas purification standards will occur. The melamine reaction process using urea as the raw material produces a large amount of ammonia and carbon dioxide gas by-products. At the same time, due to the need to supplement part of the ammonia gas during the operation process, 1.02 tons of ammonia and 1.13 tons of carbon dioxide mixed gas need to be discharged to produce 1.0 tons of melamine, commonly known as melam...

AI Technical Summary

Problems solved by technology

The manufacturing processes of these types of products are faced with the dilemma of overcapacity of related products and sluggish market; the process of co-production of urea is faced with the problems of large amount of methylamine liquid entering the urea plant, high water-carbon ratio of the system and difficult operation, and the subsequent volume of dilute ammonia water is large , Steam desorption is required, and the energy consumption is high; the evaporative condensate, surface cooling liquid, and spray circulating water of the evaporative separation system of the ammonium nitrate co-production process will all contain a certain amount of fixed ammonia and free ammonia, and this part of the water will be discharged directly, not only The loss of materials is caused, and more importantly, the environment is polluted. Sewage treatment is difficult and the investment is large; in the process of co-production of soda ash, due to the composition requirements of the joint soda production, melamine tail gas is completely used to replace pure ammonia and CO needed for carbonation 2 It is difficult to realize, and no matter whether the soda tower is a Solvay tower or an external cooling tower, there is a problem of cleaning the soda tower; in the co-production process of ammonium bicarbonate, the degree of carbonization of concentrated ammonia water is high, resulting in large fluctuations in the carbonization process , gas outlet purification index CO 2 It is difficult to meet the standard, and when it is more serious, the concentrated ammonia water with high carbonization degree has no scar-dissolving effect in the carbonization auxiliary tower, and accelerates the formation of fine crystals, resulting in frequent carbonization scarring and boiling towers.

[0003] Among the various co-production processes of melamine tail gas, there are no reports and literature studies on the co-production process of hexamethylenetetramine

Images