20000-ton-annual-yield production technique of trimethylolpropane by calcium method

Abstract

The invention discloses a 20000-ton-annual-yield production technique of trimethylolpropane by a calcium method, which is divided into condensation, filtration, evaporation, calcium separation and rectification. The production technique is characterized by comprising the following steps: by using n-butyl aldehyde and formaldehyde as raw materials and industrial calcium hydroxide as an alkaline catalyst, carrying out condensation and formic acid neutralization reaction to obtain a trimethylolpropane crude product reaction solution containing byproducts ditrimethylolpropane and calcium formate;in the filtration process, separating out solid-phase residues from the reaction solution in a horizontal spiral centrifugal filtration mode; evaporating with a climbing-film evaporator, and sending the evaporative condensate back to the condensation technique; after entering the settling tank, continuously scraping calcium formate from the bottom of the settling tank, and recycling the calcium formate with a band filter; and carrying out rectification to obtain the trimethylolpropane product, wherein rectification column uses column refluxing and climbing film heating techniques, the deflector plate in the column is controlled, and meanwhile, a gas-liquid separator is mounted on a vacuum tube of the rectification column. The invention has the advantages of simple technical process, high labor rate, low production cost, energy saving and emission reduction.

Description

technical field [0001] The invention belongs to the technical field of chemical industry, and relates to a production process with an annual output of 20,000 tons of calcium-based trimethylolpropane, in particular to a method for solving the problem of tower deviation and increased production container in the calcium-based trimethylolpropane production process The new process of reaction and separation brought. Background technique [0002] In industry, TMP mainly uses n-butyraldehyde and formaldehyde as the main raw materials, and undergoes condensation reaction under the action of a basic catalyst to produce the intermediate dimethylol butyraldehyde, which is further reacted with formaldehyde to generate trimethylolpropane. At present, the production process of trimethylolpropane in China is divided into sodium method and calcium method, that is, sodium hydroxide or calcium hydroxide are used as raw materials. The calcium process has gradually replaced the sodium process ...

AI Technical Summary

Problems solved by technology

[0007] Because most of the existing technologies adopt the above-mentioned process and the amount of solvent recovery is large, the production capacity has not been increased, because if the production is simply increased to 20,000 tons on the basis of the existing 10,000 tons production line, the following situations will occur : 1. Condensation reaction is an exothermic reaction. Uneven mixing during the reaction will lead to excessive local temperature, resulting in increased side reactions and impurities, which will bring difficulties to subsequent production, and even local burning.

2. Now trimethylolpropane has an extraction process, the ratio of the amount of extractant to the reaction solution is 3:1 by volume

The consumption of extractant is large, the production cost is increased, and the recovery of a large amount of extractant will lead to uneven distribution during operation of the rectification tower, partial flow of the rectification tower, decrease in product content, and increase in chroma; 3. Trimethylolpropane They are all high concentration, the content is above 99.5%, and the high vacuum of trimethylolpropane cannot be guaranteed

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