The present invention relates to a method for preparing paraffin, and can provide a method for preparing paraffin including a hydrogenation step of by-products of a process for preparing linear alpha olefins. Since the method for preparing paraffin of the present invention can convert the by-products of the process for preparing linear alpha olefins to paraffin at a high conversion ratio, it is possible to increase the added value of the by-products.

Device and process for converting a feedstock of aromatic compounds, in which the feedstock is notably treated using a fractionation train (4-7), a xylenes separating unit (10) and an isomerization unit (11), and in which a pyrolysis unit (13) treats a second hydrocarbon-based feedstock, produces a pyrolysis effluent feeding the feedstock, and produces a pyrolysis gas comprising CO, CO2 and H2; a WGS water gas shift reaction section (50) suitable for treating the pyrolysis gas and for producing a WGS gas enriched in CO2 and in hydrogen; a CO2 aromatization reaction section (52) suitable for: at least partly treating the WGS gas to produce a hydrocarbon effluent comprising aromatic compounds, and feeding the feedstock with the hydrocarbon effluent.

Device and process for converting a feedstock of aromatic compounds, in which the feedstock is notably treated using a fractionation train (4-7), a xylenes separating unit (10) and an isomerization unit (11), and in which a pyrolysis unit (13) treats a second hydrocarbon-based feedstock, produces a pyrolysis effluent feeding the feedstock, and produces a pyrolysis gas comprising CO, CO2 and H2; a WGS water gas shift reaction section (50) suitable for treating the pyrolysis gas and for producing a WGS gas enriched in CO2 and in hydrogen; a CO2 aromatization reaction section (52) suitable for: at least partly treating the WGS gas to produce a hydrocarbon effluent comprising aromatic compounds, and feeding the feedstock with the hydrocarbon effluent.

System and method for producing 1-butene are disclosed. The method includes dehydrogenating butane to form a mixture comprising butene isomers. 1-butene is separated from the mixture using a system that includes a membrane. The system also includes an isomerizing unit for isomerizing cis-2-butene and trans-2-butene to form additional 1-butene.

Plant and process for the production of liquid methane from a feed gas stream comprising at least methane and carbon dioxide. A feed gas stream is injected into a CO.sub.2 crystallizer in countercurrent fashion against a stream of predominantly liquid methane, thereby crystallizing amounts of carbon dioxide from the feed gas stream. Gaseous methane recovered from the CO.sub.2 crystallizer is liquefied at a liquefaction exchanger.

Plant and process for the production of liquid methane from a feed gas stream comprising at least methane and carbon dioxide. A feed gas stream is injected into a CO.sub.2 crystallizer in countercurrent fashion against a stream of predominantly liquid methane, thereby crystallizing amounts of carbon dioxide from the feed gas stream. Gaseous methane recovered from the CO.sub.2 crystallizer is liquefied at a liquefaction exchanger.

A process for oxidizing methyl-substituted biphenyl compounds comprises contacting a mixture comprising isomers of at least one methyl-substituted biphenyl compound with a source of oxygen, wherein the mixture comprises at least 20 wt % of isomer(s) having a methyl group at a 2-position or a 3-position on at least one benzene ring and at least 50 wt % of isomer(s) having a methyl group at a 4-position on at least one benzene ring, wherein said percentages are based on the total weight of the at least one methylbiphenyl compound in the mixture.

A process for oxidizing methyl-substituted biphenyl compounds comprises contacting a mixture comprising isomers of at least one methyl-substituted biphenyl compound with a source of oxygen, wherein the mixture comprises at least 20 wt % of isomer(s) having a methyl group at a 2-position or a 3-position on at least one benzene ring and at least 50 wt % of isomer(s) having a methyl group at a 4-position on at least one benzene ring, wherein said percentages are based on the total weight of the at least one methylbiphenyl compound in the mixture.

A method of recovering paraxylene in a pressure swing adsorption unit with varying hydrogen purge pressures. The pressure swing adsorption zone is adapted to adsorb and desorb paraxylene based on the cycling of partial pressure in the zone. A first hydrogen purge is fed concurrent to the feed. A second hydrogen purge is countercurrent to the feed.

A method of recovering paraxylene in a pressure swing adsorption unit with varying hydrogen purge pressures. The pressure swing adsorption zone is adapted to adsorb and desorb paraxylene based on the cycling of partial pressure in the zone. A first hydrogen purge is fed concurrent to the feed. A second hydrogen purge is countercurrent to the feed.