Verfahren zur Abtrennung von Acetylenen aus gasfoermigen Kohlenwasserstoffgemischen

摘要

Hydrocarbons are purified by absorption of impurities with selective solvents and the solvent stream is heat-exchanged with a solvent which has been stripped and is being recycled to the absorption zone in two separate stages with an extraneous heat-exchange cooling step between the two heat exchange steps. The depleted solvent and the purified gas may be contacted with a liquefied pure gas so as to remove any solvent in the purified gas and to saturate the depleted solvent with the gas which has to be obtained in a pure state and thus prevent any gas being absorbed from the initial gas stream. Exemplified is the purification of ethylene, obtained as an off-gas from a polyethylene producing process, in which acetylene is removed. Solvents which may be used in separating acetylene and/or methyl acetylene from olefins include dimethyl formamide, acetone, acetic anhydride, butyrolactone, N-methyl-2-pyrrolidone and dimethylsulphoxide. Butadiene can be separated from butenes employing either anhydrous or aqueous furfural ; propylene may be separated from propane using dimethylformamide and aromatic hydrocarbons may be separated from aliphatic hydrocarbons employing diethylene glycol or triethyleneglycol.ALSO:Gaseous mixtures are purified by absorption of impurities with selective solvents and the solvent stream is heat-exchanged with a solvent which has been stripped and is being recycled to the absorption zone in two separate stages with an extraneous heat-exchange cooling step between the two heat-exchange steps. The depleted solvent and the purified gas may be contacted with a liquidified pure gas so as to remove any solvent in the purified gas and to saturate the depleted solvent with the gas which has to be obtained in a pure state and thus prevent any gas being absorbed from the initial gas stream. Exemplified is the purification of ethylene, obtained as an off-gas from a polyethylene producing process, in which acetylene is removed. Solvents which may be used in separating acetylene and/or methyl acetylene from olefins include dimethyl formamide, acetone, acetic anhydride, butyrolacetone, N-methyl-2-pyrrolidone and dimethylsulphoxide. Butadiene can be separated from butenes employing either anhydrous or aqueous furfural; propylene may be separated from propane using dimethylformamide and aromatic hydrocarbons may be separated from aliphatic hydrocarbons employing diethylene glycol or triethyleneglycol.