Technological method for jointly preparing liquid hydrogen cyanide and hydroxynitrile

Abstract

The invention provides a technological method for jointly preparing liquid hydrogen cyanide and hydroxynitrile. The technological method comprises the steps that a light oil cracking hydrogen cyanide gas mixture is used as a raw material and undergoes an ammonia removal process and a cryogenic process to obtain liquid hydrogen cyanide, wherein in the ammonia removal process, the hydrogen cyanide gas mixture is absorbed with a sulfuric acid aqueous solution; in the cryogenic process, the hydrogen cyanide gas mixture is cooled to minus 10-minus 20 DEG C, after the hydrogen cyanide gas mixture is cooled, a part of the hydrogen cyanide gas becomes liquid to obtain liquid hydrogen cyanide, and the other part of the hydrogen cyanide gas is the tail gas containing hydrogen cyanide; the tail gas containing hydrogen cyanide, which undergoes cryogenic treatment, is absorbed with a formaldehyde aqueous solution containing a catalyst to prepare a hydroxynitrile aqueous solution, and the tail gas absorbed with the formaldehyde aqueous solution directly enters an incinerator to be incinerated. By adopting the technological method, the purification efficiency and the utilization efficiency of hydrogen cyanide can be obviously improved, meanwhile, the energy consumption in the hydrogen cyanide purification process is greatly reduced and can be reduced by 90% at most, and the utilization rate of hydrogen cyanide is more than 99.9%.

Description

technical field [0001] The invention belongs to the field of chemical industry, and relates to a method for purifying hydrocyanic acid from a reaction mixture gas produced by cracking light oil and producing hydroxyacetonitrile by utilizing tail gas. Background technique [0002] Hydrocyanic acid is a widely used chemical raw material, which can be used in many fields such as medicine, pesticides, cosmetics, dyes, fertilizers, electroplating, polymer materials, photography, mining, metallurgy, etc. At present, the main production methods of hydrocyanic acid mainly include light oil cracking method, Andrussow method, BMA method and acrylonitrile by-product method. Light oil cracking is a production method in which light oil (or gasoline), liquid ammonia and caustic soda are used as the main raw materials, and petroleum coke particles and nitrogen are used as auxiliary raw materials. Mixing, preheating to 280°C, immersing the petroleum coke particle layer through the three-ph...

AI Technical Summary

Problems solved by technology

Hydrocyanic acid mixed gas greatly limits its scope of use. For example, in the synthesis of acetone cyanohydrin, in order to obtain high-purity acetone cyanohydrin, high-purity hydrocyanic acid liquid is usually used; butadiene is produced by reacting with hydrocyanic acid Adiponitrile has very high requirements for the purity of hydrocyanic acid, especially for water and oxygen in hydrocyanic acid. For the production of these compounds, hydrogen cyanide mixed gas cannot replace high-purity hydrogen Cyanic acid liquid

In order to obtain high-purity liquid hydrocyanic acid, it is inevitable to adopt the method of absorption and rectification. In the traditional hydrocyanic acid purification process, the method of absorbing hydrocyanic acid is mostly water absorption, which not only requires the absorption of hydrocyanic acid The water is frozen to a lower temperature, resulting in high energy consumption for lowering the temperature, and the concentration of hydr