SU524790A1 - Method for extracting acetaldehyde from non-convertible acetaldehyde synthesis gases - Google Patents

Description

one

This invention relates to a process for the recovery of acetaldehyde from non-convertible acetaldehyde synthesis gases by direct catalytic oxidation of ethylene in the presence of an aqueous solution of a catalyst containing salts of palladium chloride and copper.

After acetaldehyde is stripped from the circulating catalyst solution, a small amount of acetaldehyde remains in it, equilibrated to the vapor. The acetaldehyde remaining in the catalyst solution, as well as part of the acetic acid, is removed with the exhaust air when the latter is separated from the catalyst solution.

There is a known method for separating acetaldehyde from exhaust air and other inert gases by washing it in scrubbers irrigated with water at a pressure of 1.1-20 at.

At the same time, water can be fed in a countercurrent both in one upper part of the scrubber, and in two parts - upper and lower.

A known method for extracting acetaldehyde from non-convertible gases during the synthesis of acetaldehyde is by direct catalytic oxidation of ethylene by washing it with water in a scrubber fed to the upper part of the scrubber at 35–40 ° C and to the lower part at 50–60 ° C.

The degree of acetaldehyde recovery is 0.02-0.3 weight. %

However, insufficiently high acetaldehyde recovery from non-convertible gases leads to pollution of the surrounding atmosphere.

To increase the recovery of acetaldehyde to 0.01 wt. % of non-convertible acetaldehyde synthesis gases by direct catalytic oxidation of ethylene according to the proposed method is washed in a scrubber, and the wash water is supplied to the upper part of the scrubber at 10-25 ° С and to the lower part - at 30-40 ° С. The ratio of water supplied to the top and bottom of the scrubber is 0.5-2-1: 1.

Water can be removed from the upper part of the scrubber independently from a deaf tray that separates the scrubber into two parts by liquid, or from the bottom of the scrubber with water added to the lower part.

The supply of wash water at this temperature in the specified ratio can significantly improve the cleaning of acetaldehyde from gases and thereby increase the yield of acetaldehyde.

Example 1. On. the scrubber serves 22.5 t / h of gas at 112 ° C with an acetaldehyde content of 2 wt. % Scrubber pressure 12 am.

Water is supplied to the upper part of the scrubber at 15 ° С, at the lower part - at 30 ° С at a ratio of 1: 1.6. Obsh, its amount of water is 50.

The residual content of acetaldehyde in the gas at the exit of the scrubber is 0.01 wt. %

Example 2. The scrubber serves gas at a temperature, pressure and in the amount specified in example 1.

Water is supplied to the upper part of the scrubber at 10 ° C, to the lower part at 40 ° C at a ratio of 1: 2.0. The total amount of water is 53. The residual content of acetaldehyde in the gas is 0.01 wt. %

Example 3. The scrubber serves gas at a temperature, pressure and in the quantities specified in example 1.

In the upper part of the scrubber serves water at 25 ° C, in the lower - at 40 ° C at a ratio of 1: 1. General water quantity 55. The residual content of acetaldehyde is almost zero.

Example 4. The scrubber serves gas at a temperature, pressure and in the quantities specified in example 1.

Water is supplied to the upper part of the scrubber at 10 ° С, at the lower part - at 35 ° С at a ratio of 0.5: 1. Obsh, its amount of water is 51.

The residual content of acetaldehyde is 0.1 weight. %

Example 5. Gas is supplied to the scrubber at a temperature, pressure and in the amount indicated in Example 1.

Water is supplied to the upper part of the scrubber at 15 ° С, at the bottom - at 35 ° С at a 1: 1 ratio. The total amount of water is 52. The residual content of acetaldehyde in the gas is almost zero.

Claims (1)

Invention Formula A method of extracting acetaldehyde from non-convertible acetaldehyde synthesis gases by direct catalytic oxidation of ethylene by washing it with water supplied to the upper and lower parts of the scrubber, characterized in that, in order to increase the degree of acetaldehyde recovery, water is fed to the upper part at 10-25 ° C, and in the lower part at 30-40 ° C with the ratio of the amount of water supplied to the upper and lower parts of the scrubber, 0.5: 2-1: 1.