Abstract: The invention is a process for the denitrogization of a liquefied natural gas (LNG) comprising methane and at least 2 Mols. of nitrogen. The process is distinguished in that the LNG is introduced into the process as a liquid and is subject to an indirect heat exchange to cool the liquid and a further decompression before introduction into fractionation of column. A portion of the liquid flowing in the fractionation column is withdrawn and utilized to cool the LNG feedstock and is returned to the fractionation column at a level lower than the level from which it was withdrawn. The decompression of LNG feedstock comprises at least one dynamic decompression and at least one static decompression.

Abstract: Process for the simultaneous decarbonation and gasoline stripping of a gaseous mixture at an absolute pressure higher than 0.5 MPa containing methane, C.sub.2 and higher hydrocarbons and CO.sub.2 in which a demethanized rich solvent is regenerated so the process can be carried out more easily and at lower costs than previously known systems.

Abstract: A method of liquefying natural gas, wherein the gas (1) is cooled and separated into a liquid phase (6) and a gaseous phase (8) which is expanded (9) and added to the liquid phase in the column (7), at the head of which the gas enriched with methane (21) is separated and recompressed (27) and carried to the liquefaction (32, 33, 34) whereas the liquid phase from the bottom of column (7) is expanded and rectified in column (14); the head effluent (19) being condensed (20) and conveyed as a reflux (25) to column (7); the pressure in column (7) being higher than that of column (14); the C.sub.3 + hydrocarbons from the bottom (16) being separated and the methane liquefaction (33, 34) being conventional.

Abstract: A method of and a plant for recovering liquid hydrocarbons in a gaseous batch, the plant comprising a compressor for the gaseous batch, a column for absorbing C5 and heavier hydrocarbons associated with a debutanization column; a column for absorbing C3 and heavier hydrocarbons associated with a de-ethanization column and with a heat exchange system connected to a refrigeration cycle, the plant providing from a gaseous batch issuing from a catalytic cracking unit a debutanized gasoline, a liquefied gas cut (C3 and C4-hydrocarbons) and a gaseous cut (C2 and lighter hydrocarbons) wherein the losses of C3 and higher C-hydrocarbons are much smaller than that occurring with existing plants.

Abstract: A cryogenic process of simultaneous selective desulphurization and gasoline removal of a gaseous mixture consisting mainly of methane and likewise containing H.sub.2 S and hydrocarbons with C.sub.2 and more.Said gaseous mixture (1), after having eventually undergone an operation of removal of benzol (25) and then cooling (2) producing condensates (4), is washed between 0.degree. C. and -45.degree. C. by means of a solvent (5) selective of H.sub.2 S to produce a current of methane (64) having a partial pressure in H.sub.2 S below 65 Pa and a liquid phase (9a) rich in H.sub.2 S and containing at least 80% molar of the hydrocarbons of C.sub.3 and more of the gaseous mixture (1). The liquid phase (9a) is subjected to a demethanization (29, 9) producing a demethanized rich solvent (11) and a gaseous phase rich in methane (10), the solvent (11) then is cooled between -25.degree. and -80.degree. C. sufficiently to produce its dissociation in a lower liquid fraction (38) that contains the H.sub.

Abstract: The invention relates to a method and an apparatus for cryogenic fractionation of a gaseous feed comprising a contact purifying-refrigerating column into the bottom of which is injected a partially condensed gaseous feed, the said column producing in its head portion a residual gas and in its bottom portion a liquid which is injected into a fractionating column producing in its head portion a distillate which is at least partially condensed and injected into the head portion of the column to thus recover in the bottom liquid of this column the heavy compounds contained in the vaporized fraction of the gaseous feed.

Abstract: The present invention relates to a process and an apparatus for cryogenic fractionation of gas feeds, the apparatus comprising essentially a contact purifying-refrigerating column associated with a fractionating column, an exchange system, a plurality of ducts with valves connecting the above three elements and two closed end independent refrigerating circuits integrated to the exchange system.

Abstract: The process consists in successively separating increasingly heavy petroleum cuts at the head of a plurality of columns CO1, CO2, CO3 and Cl0 of a first series of columns which feed individually each column of the second series. The column CO7 is a gasoline stabilizing column which feeds an installation for fractionating light petroleum gases. The column CO4 is a gasoline fractionating column. The columns CO5 and CO6 are columns for separating petroleum naphthas from kerosine. The atmospheric residue collected at the bottom of the column Cl0 is processed in the vacuum distillation column Cl2 and the residue from this column is processed in the second vacuum distillation column Cl3 after reheating in a furnace.By carrying out a succession of progressive separations performed in a series of columns of small volume, more efficient utilization of the recovery heat is achieved.

Abstract: The present invention relates to a method and an apparatus for liquefying a gas with a low boiling point, such as natural gas, by heat exchange with a main refrigerant fluid having several components. The whole of the vapor phase of this main refrigerant fluid, after being condensed and subcooled, is expanded at once to at least one first pressure, and the whole of the liquid phase of the subcooled main refrigerant fluid is expanded at once to at least one second pressure, different from the said first pressure.

Abstract: A process of and apparatus for liquefying a dry gas with low boiling point in a first circuit through heat exchange with a main refrigerating fluid in a second circuit itself pre-cooled to its at least partial liquefaction through heat exchange with an auxiliary refrigerating fluid in a third circuit, wherein, for a same amount of treated products, the required total compression input power for the refrigerating fluids is reduced by performing in said third circuit an intermediate condensation between the two last compression stages followed by a phase separation, the gaseous phase being compressed to a high pressure in the last compression stage whereas the liquid phase is compressed to a high pressure by a pump and recycled to a cryogenic heat exchanger for cooling the gas initially in the moist state thereby at least partially drying same.

Abstract: A process of and an apparatus for saving energy in a method of liquefying a natural gas by cooling same with the vapor from a liquid coolant sub-cooled after expansion thereof in the liquid condition, the vapor simultaneously sub-cooling the liquefied coolant, the process consisting in expanding the sub-cooled high-pressure liquid coolant in a hydraulic turbine providing mechanical power possibly for driving a rotary machine.

Abstract: Method of liquefying a mixture of gas rich in methane by performing an auxiliary cycle and a main cycle in which are used an auxiliary and a main refrigerating fluid of several components. In each cycle are performed the compression, cooling, liquefying and sub-cooling of the refrigerating fluids in counter-flowing relationship with themselves after expansion-vaporization in a heat exchanger. The gas to be liquefied is cooled in parallel with said main refrigerating fluid which has been pre-cooled in the auxiliary cycle. Pre-cooling of said gas is performed in an exchanger cooled by the refrigerating main fluid after its expansion-vaporization in said heat exchanging column of said main cycle and before its re-compression.

Abstract: Method and apparatus for cooling a gaseous mixture wherein a fractional condensation of said mixture is carried out under a high pressure by using at least a first stage and a last stage of fractional condensation, the penultimate and the last condensed fractions are expanded down to a low pressure forming a main refrigerating stream, and at least the first condensed fraction of the cycle mixture is expanded down to an intermediate pressure between said high pressure and said low pressure forming an auxiliary refrigerating stream.

Abstract: A method of processing through low temperature heat exchanges natural gases and cracked gases consisting in using a cooling cycle including compressing and then cooling a cycle mixture of gases consisting of C1 hydrocarbons, C2 hydrocarbons and C3 hydrocarbons through outer coolers with attendant total liquefaction of the cycle mixture under pressure; subsequently effecting a sub-cooling of the mixture within heat exchanges in counter-current relation to one expanded part thereof and/or cold returns and rejects of products processed in the cycle and finally expanding said sub-cooled mixture in at least one exchanger where various cooling processes of the treated products are carried out at successive temperature levels.