Abstract: Methods and systems for treating an olefin-containing stream are disclosed. The disclosed methods and systems are particularly suitable for treating an off-gas stream in a refining or petrochemical process, such as from a fluid catalytic cracker (FCC), coker, steam cracker, and the like. The stream is treated in an absorber column to reject lighter stream components and to absorb ethylene and/or propylene into a solvent. The solvent is typically isobutane. The enriched solvent stream from the absorber column is fed to an alkylation reactor, which reacts the dissolved olefin with the isobutane solvent to produce an alkylate product.

Abstract: Methods and systems for treating an olefin-containing stream are disclosed. The disclosed methods and systems are particularly suitable for treating an off-gas stream in a refining or petrochemical process, such as from a fluid catalytic cracker (FCC), coker, steam cracker, and the like. The stream is treated in an absorber column to reject lighter stream components and to absorb ethylene and/or propylene into a solvent. The solvent is typically isobutane. The enriched solvent stream from the absorber column is fed to an alkylation reactor, which reacts the dissolved olefin with the isobutane solvent to produce an alkylate product.

Abstract: Methods and systems for treating an olefin-containing stream are disclosed. The disclosed methods and systems are particularly suitable for treating an off-gas stream in a refining or petrochemical process, such as from a fluid catalytic cracker (FCC), coker, steam cracker, and the like. The stream is treated in an absorber column to reject lighter stream components and to absorb ethylene and/or propylene into a solvent. The solvent is typically isobutane. The enriched solvent stream from the absorber column is fed to an alkylation reactor, which reacts the dissolved olefin with the isobutane solvent to produce an alkylate product.

Abstract: A demethanizer employing C3, C4 and C4+ hydrocarbons as absorbents can be employed in a methanol to olefin process to reduce both operating and capital costs in comparison to a convention process which employs only cryogenic distillation to remove methane and other low boilers from a light olefin process stream. By reducing the use of propane, the size and operating costs of the C3 splitter can be reduced thereby providing an economic advantage over conventional applications.

Abstract: A method of cooling an ethylene discharge gas includes the steps of drawing a liquid ethane from a C2 splitter; reducing a pressure of the drawn liquid ethane in a let-down valve to produce a cooled liquid ethane; cooling the ethylene discharge gas with the cooled liquid ethane in a vaporizer, the cooled liquid ethane exiting the vaporizer as an ethane vapor; pressurizing the ethane vapor in a heat pump to produce a heated vapor ethane; and returning the heated vapor ethane to the C2 splitter. The ethylene discharge gas may be from an ethylene refrigerant compressor.

Abstract: A demethanizer employing C3, C4 and C4+ hydrocarbons as absorbents can be employed in a methanol to olefin process to reduce both operating and capital costs in comparison to a convention process which employs only cryogenic distillation to remove methane and other low boilers from a light olefin process stream. By reducing the use of propane, the size and operating costs of the C3 splitter can be reduced thereby providing an economic advantage over conventional applications.

Abstract: A low-pressure olefins recovery process and plant are described. The feed gas is compressed and distilled at a primary distillation pressure. The overhead stream is chilled at a pressure less than 30 kg/cm2 (430 psia) to partially condense the overheads. The primary distillation tower is refluxed with at least a portion of the condensate. The overhead vapor is further chilled and partially condensed and the condensate is fed to a demethanizer. The remaining vapor is cooled in a cold section and the resultant liquid is phase-separated and expanded to provide refrigeration for the cold section. The expanded vapor from the cold section is recycled to the process gas compressor. The bottoms streams from the primary distillation zone and the demethanizer are fractionated into respective streams consisting essentially of ethylene, ethane, propylene, propane, C4's, and C5+.

Abstract: A low-pressure olefins recovery process and plant are described. The feed gas 300 is compressed 302, 304 and distilled 310 at a primary distillation pressure. The overhead stream 312 is chilled 318 at a pressure less than 30 kg/cm2 (430 psia) to partially condense the overheads. The primary distillation tower 310 is refluxed with at least a portion of the condensate 320. The overhead vapor is further chilled 318 and partially condensed and the condensate 322 is fed to a demethanizer 324. The remaining vapor 326 is cooled in a cold section 328 and the resultant liquid is phase-separated 330 and expanded 331, 334 to provide refrigeration for the cold section. The expanded vapor 332 from the cold section is recycled to the process gas compressor. The bottoms streams 338, 342 from the primary distillation zone and the demethanizer are fractionated into respective streams consisting essentially of ethylene 356, ethane 358, propylene 364, propane 366, C4's 346, and C5+ 348.

Abstract: A hybrid condensation-absorption process and unit is disclosed for the recovery of olefins. A mixed-component stream containing hydrogen, methane and olefins is compressed and refrigerated against propylene refrigerant to partially condense the stream. The condensate is stripped of volatile components and fed to a fractionation unit such as a deethanizer. The volatile components stripped from the condensate and the non-condensed vapor from the mixed-component stream are fed to a solvent absorption unit to remove olefins which are absorbed in the solvent. The olefins-rich solvent is regenerated to recover olefins and lean solvent. The lean solvent is recirculated to the absorption unit. The olefins recovered from regeneration of the solvent are fed to the fractionation unit along with the pre-stripped condensate. Vapor from the absorption unit is cryogenically processed to recover a crude hydrogen product, a fuel gas product and residual olefins which can be recycled to the absorption unit.

Abstract: A method is described for recovering olefins by condensation from the reaction effluent stream from a cracking furnace containing olefins and hydrogen wherein a membrane separator is employed to reject the hydrogen from the reaction effluent stream. In such a manner, the dew point temperature of the stream can be increased and the energy required to provide refrigeration for olefin condensation can be reduced. The method comprises primary condensation, vapor-liquid separation and membrane hydrogen rejection steps followed by a series of cascaded chilling and vapor-liquid separation steps. Condensate recovered is processed in a demethanizer to separate light end components. Also disclosed is an olefins plant employing a membrane separator for rejecting hydrogen to enhance the energy efficiency and/or facilitate the expansion of plant capacity.

Abstract: An enhanced method is disclosed for recovering olefins from a cracking furnace effluent stream in an olefins plant. In accordance with this method, a liquid hydrocarbon stream, preferably obtained from the compressor area drier liquids and/or from the deethanizer or depropanizer, is injected into the reaction effluent stream to condition the reaction effluent stream for enhanced condensation against propylene refrigeration. Also disclosed is an olefins plant utilizing liquid hydrocarbon injection and an improvement to existing olefins recovery process technology using liquid hydrocarbon injection for vapor stream conditioning.