SU990279A1 - Method of purifying gases from moisture and hydrocarbon impurities - Google Patents

Description

(54) METHOD FOR CLEANING GAS FROM IMPURITIES IN MOISTURE AND HYDROCARBONS

one

The invention relates to a technique for extracting water and organic substances, including hydrocarbons, from gas mixtures, and more specifically to a technique for extracting water, hydrocarbons and other substances from waste gases produced by the liquid-phase oxidation of hydrocarbons.

It is known that hydrocarbon vapors in a mixture with steam. Of water, during their processing at temperatures below 0 ° C, are capable of forming hydrated ice, which clogs the process equipment, disrupting its normal operation, for example, in separation processes, Ct-Cg hydrocarbon mixtures. Taking this circumstance into account, gas mixtures containing water vapors, hydrocarbons, are dried using adsorbents before they are processed in the temperature range below 0 ° C. I.

The disadvantage of this method is that it does not provide complete extraction of water vapor, low boiling point products: methyl acetate, acetone, and, moreover, Cs-Cg hydrocarbons, which constitute the bulk of the raw hydrocarbon feedstock.

The closest to the invention in its technical essence and the achieved result is a method for purifying gases from moisture and hydrocarbon impurities by stepwise cooling with a drying after reaching temperature O-10 ° C by adsorption on zeolites 2.

The disadvantage of this method is that the degree of purification of gas from hydrocarbons is rather high (the residual content of y / l is). In addition, when the gas is cooled to a temperature of the order of minus 20 ° C and below, the loss of hydrocarbons and other organic substances is 10 more than 15% of the raw material.

The purpose of the invention is to increase the degree of purification.

This goal is achieved according to the method of purifying gases from moisture and hydrocarbon impurities by means of stepwise cooling with condensation of impurities and after drying after reaching the cooling temperature of the gas mixture equal to O-10 ° C, in which the drying is carried out by contacting with propionic acid.

At the same time, the step cooling is up to minus 35, minus 40 ° С.

Moreover, propionic acid is taken in the amount of 0.5-2 weight. ° / o.

The proposed method allows to reduce the hydrocarbon content in the final

gas mixture from 2-3 to 0.6-0.7%, i.e., 3-3.5 times. Propionic acid, which is introduced in an amount of 0.5-2% of the amount of waste and gas emitted into the atmosphere, is one of the products of the process, and therefore, without regeneration, it returns to the reactor in a mixture with the total condensate flow. The amount of propionic acid added is controlled depending on the gas load and the cooling conditions of the condensers.

The proposed method is applied to the waste gases of the liquid-phase oxidation of light gasolines, in addition, the proposed method can be successfully applied to the processes of liquid-phase butane oxidation, to capture low molecular weight GI-4 acids from waste gases, oxidation of paraffin to synthetic fatty acids, alcohols similar processes.

Example. The gas after the reactor enters the waste heat boiler, in the annular space of which water evaporates. In the boiler, the gas temperature is reduced from 180 to 150 °. The resulting gas condensate mixture is separated in a separator, however, in front of the separator, condensate obtained in the second cooling stage after its separation from the gas is mixed in to this stream. A mixture of condensates from the separators flows into the collector. By mixing the cold condensate stream from the separator, the temperature of the condensate and gas in the separator is reduced to 110 °. Then cooled to 55 ° in the condenser, the gas from the separator is supplied for cooling. From the separator, where the temperature of the gas and condenser due to the mixing of the cold stream is minus 25 °, the condensate flows into the collector and the gas is directed to cooling.

The temperature of the gas condensate mixture after the condenser is minus 5 ° C. At this temperature, the mixture enters a continuously operating absorber, irrigated cooled to minus 10, minus 15 ° with propionic acid supplied to the middle part of the absorber, and a condenser representing a mixture of acetone, methyl acetate, and hydrocarbons with a temperature of € 4 - CgC minus 15, minus 20 °

Thus, the lower plates of the absorber work to absorb water and organic matter, and the upper plates to wash out the acid. The dried, washed and cooled to minus 5 ° gas further enters the condenser cooled by gas having a temperature of -35 ° C. After the separator, where the condensate that irrigates the absorber occurs, the gas flow enters the last cooling stage, where it is cooled to -40 ° due to the exhaust and cooled to minus 55, minus 65 ° gases from the turboexpander. According to preliminary data, the organic matter content in the exhaust gas is 0.6-0.7%, which is 3.5 times less than in the known method. This makes it possible to effectively use the proposed method to remove harmful components.

Claims (3)

1. A method for purifying gases from moisture and hydrocarbon impurities by step cooling with condensation of impurities and after drying after reaching a cooling temperature of the gas mixture equal to O-10 ° C, characterized in that, in order to increase the degree of purification, the drying is carried out by contacting with propionic acid . 2. A method according to claim 1, characterized in that the step cooling is conducted to a temperature of minus 35 ° C, minus 40 ° C. 3. Method of pl. 1 and 2, characterized in that the propionic acid is taken in an amount of 0.5-2 wt. % Sources of information taken into account during the examination 1. P. Markos. On some issues of gas separation. Author. dis. Baku, VNIIOlefin, 1952. “Oil and Gas J, 1973, 71, No. 24, p. 108-109 (prototype).