Abstract: A cryogenic process for the removal of acidic gases from natural or synthetic gases comprising preliminary cooling of the gas to condense a portion of the acidic gases contained in the gas, and contacting the cooled gas with a mixture of one or more organic selective solvents such as low molecular weight esters, alcohols and ethers and one or more organic compounds such asheptane,fractions of natural gasoline containing hydrocarbons;monoaromatic compounds;dimethylethers of polyglycols having the glycolic unit CH.sub.2 --CH--O-- repeated three to five times;methoxy- and/or ethoxyalcohols, wherein the alcoholic group is a radical having from 3 to 4 carbon atoms in either linear or branched chain.

Abstract: A cryogenic process is disclosed for the selective removal of acidic gases from natural gases or from synthesis gases by adsorption in two towers and cooling of the gas outcoming from the first tower to the purpose of condensing a portion of CO.sub.2 contained in the same gas, which is characterized in that in it a mixture is used constituted by one or more selective solvents selected among low molecular weight esters, alcohols and ethers.

Abstract: Cryogenic process for the removal of acidic gases from natural gases or from synthesis gases essentially comprising the absorption in one or more towers in order to reduce the content of acidic gases, a cooling carried out, in the case of one single absorber tower, upstream the same tower, or, in case of two absorber towers, between the same towers, a regeneration of the solvent or of the solvents used in the absorption, the solvent or the solvents used being selected among low molecular weight esters, alcohols and ethers, characterized in that with the solvent or solvents the gas outcoming from one or more of the absorber towers is mixed once or more times, the mixtures thus formed being then cooled, the solvent being thus separated from the same gas.

Abstract: A process is disclosed for the recovery of heavy constituents from high-pressure hydrocarbon gaseous mixtures comprising the steps of first cooling and partially condensing the gaseous mixture. The condensed liquid is then separated and fed to a fractionation column while the remaining non-condensed gaseous mixture is subject to turboexpansion. The liquid condensed on turboexpansion is then separated and fed to the fractionation column where the heavy constituents are recovered. The gases streaming from the fractionation column and those separated by turboexpansion are compressed, separately or together, up to the consignment pressure of the treated gas. This process is characterized in that the liquid condensed on turboexpansion is separated in a separator-absorber wherein, in addition to the condensed liquid, a liquid obtained by the absorption of the non-condensed heavy constituents is collected.

Abstract: A process for removing acid gases from natural or synthesis gases by absorption, comprising the following stages:(a) cooling the natural or synthesis gas to be purified to condense part of the CO.sub.2 contained in said gas;(b) feeding the cooled and partly condensed gas to an absorption column in order to reduce the acid gas content to the required value;(c) regenerating the solvent or solvents used in the acid gas absorption, the solvent or solvents used being chosen from esters, alcohols and ethers of low molecular weight.

Abstract: A cryogenic process for removing acid gases from natural or synthesis gases, comprising the following stages:(a) feeding the natural or synthesis gas to a first absorption column in order to absorb the H.sub.2 S;(b) cooling the substantially H.sub.2 S-free gas to condense part of the CO.sub.2 contained in said gas;(c) feeding the cooled and partly condensed gas to a second absorption column in order to reduce the CO.sub.2 content to the required value;(d) regenerating the solvent or solvents used in the acid gas absorption, the solvent or solvents used being chosen from esters, alcohols or ethers, of low molecular weight.

Abstract: There is disclosed a process for selectively separating hydrogen sulfide from gaseous mixtures which also contain carbon dioxide by chemical absorption with a substantially anhydrous solution of a tertiary amine, such as methyl diethanolamine, and an auxiliary organic solvent, such as sulfolane.

Abstract: A process is described for stripping acidic gases, mainly hydrogen sulphide and carbon dioxide, from natural gas or synthesis gas, especially when the percentages of such acidic gases are high and the conventional processes become economically objectionable.The process is based on the use of a number of selective solvents, generally belonging to the class of esters, ethers, mixed ester-ethers and lactones, in combination with sequential absorbing cycles which start from the stripping of hydrogen sulphide, and comprise the regeneration of the solvents used by several expansion cycles: H.sub.2 S and CO.sub.2 are recovered and the regenerated solvents recycled.

Abstract: Low temperature treatments are combined with solvent treatments using particularly selective solvents for stripping acidic gases such as carbon dioxide and hydrogen sulphide from natural gas or from synthetic gases.The preferred solvents are a wide range of compounds having an esteric or an etheric function in their molecule, but there are also examples of compounds which have the two functions simultaneously.The stripping process is comparatively simple, is efficient, especially for high contents of acidic gases in the raw gas streams, and is economically acceptable.

Abstract: In a method for the refrigerative fractionation of cracking gases in ethylene production plants, the improvement consisting in that ethane is used as the refrigeration fluid, it being thus possible to attain very low temperatures, down to minus 88.degree. C.: concurrently, the condensation with water is practicable whenever water is available in large masses at a temperature which is in the range from zero centigrade to +25.degree. C.; that is the case of sea waters in cold countries or fresh waters in cold climate. A considerable first-cost and running economy become thus available.