SU138243A1 - The method of purification of ethylene from sulfur impurities - Google Patents

Description

The use of magnesium oxide for chemisorption of sulfur compounds is known. For example, the use of liquid glass with magnesium oxide for the purification of water gas from carbon dioxide and carbon disulfide at a temperature of 350-400 ° C is described.

The use of this sorbent for the purification of ethylene from sulfur compounds did not give a positive result due to the disproportionation of ethylene at 400 °.

It is also known to use mixed sorbents using magnesium oxide for the removal of sulfur compounds.

The disadvantages of mixed chemisorbents are the use of elevated pressures for their operation, as well as low mechanical strength and insufficient porosity.

A method for purifying ethylene from sulfurous impurities by sorption of the latter on a solid contact (magnesium oxide from 10 to 35 wt.% On active alumina) is proposed at a temperature of 250-300 ° C at atmospheric or elevated pressure.

Spent contact retains the original strength and can be regenerated by blowing steam or air at elevated temperatures by the following reaction:

 + MgO MgS MgO 4- SOj

The above contact is prepared by precipitating magnesium hydroxide on active alumina followed by a dehydration of the sorbent at 110 °. The new sorbent is free from the disadvantages of previously known sorbents used for the chemisorption of sulfur gases.

A distinctive feature of the proposed method is an increase in the sorption surface of the contact, which allows the process

HrOIVsO,

№ 138243

under milder conditions (250-300 ° at atmospheric pressure) and reduces the possibility of disproportionation of ethylene.

Example 1. 65 g of active alumina with particles of 4-5 mVm in size are impregnated with a solution of 128.5 g of magnesium nitrate in 450 ml of water.

The mixture is evaporated and dried to dryness at 110 °, poured into it 450 ml of 15% ammonia solution and incubated for 2 hours.

Then it is again evaporated to dryness at 110 ° and the resulting contact is washed several times with 1-2% ammonia solution until the reaction to the nitrate ion disappears. The wet chemisorbent is dried at 110 ° and 100 g of contact are obtained with a content of 35% magnesium oxide.

Example 2. Contact with a 20% content of magnesium oxide, obtained in a similar way, is loaded into a steel reactor equipped with electric heating, “passing the ethylene fraction with a bulk velocity of 200 1shs-1 at atmospheric pressure and a temperature of 300 °.

The results of ethylene purification from sulfurous impurities are presented in the table:

Example 3. Contact with a 15% content of magnesium oxide was tested for 630 hours, as described in Example 2, at a temperature of 250, a volume flow rate of the ethylene fraction of 500 bc-i and a pressure of 20 atm. In the initial ethylene, before the contact, the content of the sheath, its sulfur averaged 5 mg 1 m, in the ethylene after contact the sulfur compounds were absent.

Subject invention

The method of purification of ethylene from sulfurous impurities on a solid contact based on magnesium oxide is different from the fact that, in order to increase the sorption surface and to reduce the cleaning conditions, magnesium oxide is used as a sorbent in an amount from 10 to 35% (wt.), deposited on active alumina, and the process is carried out at a temperature of 250-300 ° and atmospheric pressure.