SU787770A1 - Method of producing acetylene and ethylene mixture for gas-flame treating of metal - Google Patents

Description

(54) METHOD FOR MAKING A GAS MIXTURE OF ACETYLENE AND ETHYLENE FOR GAS FLAME TREATMENT OF METAL

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This invention relates to a technique for preparing an acetylene gas mixture for transport in acetylene cylinders.

Of all the known hydrocarbons used as combustible substances, acetylene is the most effective, and in some cases it is an irreplaceable combustible gas widely used for the flame treatment of metals, for example during welding, cutting and brazing. For transport, acetylene is introduced into cylinders filled with a porous mass and solvent, such as acetone.

It is known to use an acetylene gas mixture containing such combustible gases as ethylene, propane, propylene for the processes of welding and cutting metals without degrading the quality of work compared to using pure acetylene for these purposes. In this case, an acetylene gas mixture is obtained on site by adding one or more resistant combustible gases to acetylene 1.

However, this method of obtaining and using for the gas-flame treatment of metals an acetylene gas mixture is not effective due to the need to separately prepare each component of the gas mixture and their subsequent mixing in a predetermined molar ratio.

The processes of pyrolysis of hydrocarbon feedstock are known, as a result of which an ethane-ethylene fraction containing acetylene is obtained, and a method for separating this fraction from acetylene by absorption by sulfur-active organic solvents. The ethylene concentration in acetylene can

, 0 to be regulated by the parameters of the absorption purification process 2.

There is also known a method for producing a gas mixture consisting of acetylene and ethylene in the ratio of 39:61 to 5:95 from the pyrolysis products of the hydrocarbon feedstock and using this mixture for flame treatment of metals, including for welding, cutting and brazing steel rolled products 3.

The disadvantage of this method is that in the case of filling with known techniques, the mixture of acetylene cylinders creates explosive conditions for storing and transporting this mixture. In addition, such a wide range of mixing ratios

does not provide a uniform composition of the gas at its release from the cylinders due to the significant difference in the solubility of acetylene and ethylene in acetone (4: 1), which leads to instability of the flame temperature.

The aim of the invention is to ensure explosion safety during transportation and storage of a gas mixture of acetylene and ethylene in cylinders.

This goal is achieved by the fact that in the process of obtaining the amount of ethylene in the mixture is maintained within 5-8% by volume.

Example. Ethane-ethylene fraction isolated from pyrolysis products of virgin gasoline and having a composition, 06.%; Ethylene 74,4

Ethan24,1

Acetylene1,5

It enters a two-stage low-temperature absorption installation, where the extraction of acetylene is carried out with dimethylformamide. At the first stage, the pressure in the absorption is 28 atm, the temperature is minus 10 ° C. Desorption pressure 1,2 atm.

The composition of the desorbed gas, vol.%. Ethylene59.0

Ethan 10.9

Acetylene30,1

At the second stage, the pressure in the absorber is 1.2 atm, and the temperature is minus 7 ° C.

The composition of the second-stage stripped gas, v / v;

Acetylene95,0

Ethylene5.0

Then a gas mixture of acetylene and ethylene is introduced by known methods into acetylene cylinders.

The selected gas mixture of acetylene and ethylene from the ethylene group of the pyrolysis products of hydrocarbon feedstock is a valuable raw material for the flame treatment of metals and replaces pure acetylene used for similar purposes.

The resulting ratio of the components of the gas mixture ensures safe transportation and stable flame temperature due to the almost constant composition of the gas when released from the cylinders, which is extremely important for carrying out the processes of flame treatment of metals.

A gas mixture containing 92-95% acetylene and 5-8 vol% ethylene ensures the filling of acetylene cylinders by the maximum amount of the main component acetylene without exceeding the level of permissible pressure.

Claims (3)

Invention Formula The method of producing gas of acetylene and ethylene for gas treatment of metal by pyrolysis of hydrocarbons, characterized in that, in order to ensure explosion safety during storage and transportation of the mixture in cylinders, the amount of ethylene in the mixture is maintained within 5-8 ° C / o Sources of information taken into account in the examination. 1. French patent number 2200474. class. F 17 C 11/00 1973. 2 Klimenko A.P. The production of ethylene from oil and gas. M., Gostoitehizdat, 1962, p. 132, 133. 3. Japan patent No. 49-43242, CL 17 V 0.1970.