SE442194B - PROCEDURE FOR THE TREATMENT OF REMAINED GASES CONCERNING THE MANUFACTURE OF DICHLORETHANE BY OXICLORATION OF ONE - Google Patents

Description

8106500-5 10 1s_ 20 25 30 35 reactors with very significant dimensions are required, which in turn leads to high investments in relation to the expected production of dichloroethane.

According to the present invention, these inconveniences are eliminated. It enables the conversion of the ethylene contained in residual gases from oxychlorination to 1,2-dichloroethane with excellent yield, and the conversion takes place at a relatively low temperature, which limits the energy costs caused by heating the gases and eliminates the risks of corrosion, without that for this purpose circulation of a large amount of solvent is used.

For this purpose, chlorine is added to the residual gas containing ethylene, in a molar ratio of C12 / CZH4 which is between 0.5 and 1.5, preferably between 0.8 and 1.1. The mixture thus obtained is passed over a catalyst for a contact time of between 0.1 and 10 seconds, preferably between 0.2 and 5 seconds (the contact time is defined as the ratio between the catalyst volume (ml) and the volume flow rate (ml / sj).

The reaction temperature is between 0 and 15006 and preferably between 15 and 8000. The catalyst can e.g. be activated carbon or alumina in the form of pellets.

The conversion rate of ethylene is between 90 and 100 percent, while the yield of dichloroethane is practically quantitative. The following examples illustrate the invention without limiting it. More specifically, they were carried out on residual gases from oxychlorination of ethylene, but any inert residual gas containing ethylene or any other unsaturated hydrocarbon can be treated in the same way, thus enabling easier recovery of a higher molecular weight product.

Example 1 191 l / h of a gaseous effluent from oxychlorination of ethylene are treated, the composition being as follows: co, 2.1% co 1.2% CZH4 1.2% HCl 0.1% cnzci-cnzci 0, 03% oz 6.0% NZ s9, s7% 10 15 20 25 30 8 356500-5 with 2.23 1 / h of chlorine in vapor phase (ie a molar ratio C12 / CZH4 of 0.973) at a temperature of 70 ° C of 175 ml activated charcoal ("Acticarbone AC 40" from Société CECA SA). The contact time is thus 2.6 seconds.

Under these conditions, the conversion rate of ethylene is 97.5 percent.

Example 2 600 g / h of the gaseous effluent from Example 1 are treated with 6.9 l / h of chlorine (molar ratio C12 / CZH4 = 0.958) at a temperature of 70 ° C and of 88 ml of activated carbon, which corresponds to a contact time of 0.4 seconds.

The conversion rate for ethylene is 96 percent.

Example 3 600 l / h of the gaseous effluent from Example 1 are treated with 7.9 1 / h of chlorine (molar ratio C12 / CZH4 = 1.097) under the same conditions as in Example 2, i.e. at a temperature of 70 ° C on ss m1 activated carbon uwntaktria; The conversion rate of ethylene is 96 percent as in Example 2. 0.4 seconds). * On the other hand, you find in the gas after the treatment the excess chlorine that has not reacted, ie. can be easily eliminated by conventional 1.02 l / h, but this methods.

Example 4 180 g / h of a gaseous effluent from oxychlorination of ethylene and having the following composition are treated: coz 2.5 co 1.0 2.

CZHÅ, 1.27% CHZ-cl-c fl zci 0.12% oz 6.0 2.

NZ s 9.11% with 2.35 l / h of chlorine (molar ratio C12 / CZH4 = 0.984) at a temperature of 20 ° C of 175 ml of activated carbon. The contact time is 3.5 seconds.

Under these conditions, the conversion rate of ethylene is 97.5 percent.

Example 5 216 l / h of an effluent gas having the following composition are treated: ppyigoïk 11% 7äqFI fl open 10 15 20 ZS> 30 035 '8106500-5 4 CO 2 1.9% CO 0.8% CZH4 0.7% O2 6.0 6 N 90.6% Z with 1.38 l / h of chlorine in the vapor phase at a temperature of 50 ° C and on 175 ml of activated carbon, ie. with a contact time of 2.9 seconds.

Under these conditions, where the chlorine / ethylene molar ratio is only 0.913, the conversion rate for ethylene is 89 percent.

Example 6 168 l / h of the gaseous effluent from Example 5 are treated with 1,18 l / h chlorine (molar ratio C12 / CZH4 = 1.003) at a temperature of 90 ° C on 175 ml of alumina pellets, which corresponds to a contact time of 2 , 8 seconds.

T The conversion rate for ethylene is 97.2 percent.

Example 7 1 189 l / h of the gaseous effluent from Example 5 are treated with 1.8 l / h of chlorine (molar ratio C12 / CZH4 = 1.360) at a temperature of 50 ° C on 175 ml of alumina pellets, which means a contact time of 2.5 seconds.

The conversion rate for ethylene is 100 percent. After the treatment, the gas contains the excess chlorine that has not reacted, ie. 0.5 l / h. Example 8 i Treat 140 g / l of a gaseous effluent from the oxychlorination of ethylene and having the following composition:, co, 1.6 g co 0.1% CZH4 o, s9% cH2c1-cazcl d 0.11% oz 6% N 91 »2 with 12,6 l / h chlorine (molar ratio C12 / CZH4 = 1,873) at a temperature of 90 ° C on 175 ml of alumina. The contact time is _salunda.0.4 seconds. _ The conversion rate for ethylene is 96.6 percent. After the treatment, the gas contains the excess chlorine that has not reacted, ie. 6.1 l / h. nriåšïï 9 ~ 909% "Q '

Claims (1)

A process for treating residual gases, containing CO, resulting from the production of dichloroethane by oxychlorination of ethylene, chlorinating the residual gases in the vapor phase with chlorine in the presence of a catalyst, temperature of between 15 and 80 ° C in the presence of activated carbon as catalyst, the residence time for contact with the catalyst being between 0.1 and 10 seconds. çšooïs: orsgfftmfrïr