Abstract: Apparatuses and methods are provided for forming C8 aromatic streams with selected amounts of C9 aromatics. In one embodiment, a method for forming a C8 aromatic stream with a selected amount of C9 aromatics includes fractionating a hydrocarbon stream including C8 and C9 aromatics into a sidedraw fraction and a bottom fraction. The sidedraw fraction includes a portion of the C8 aromatics and a portion of the C9 aromatics. The bottom fraction includes remaining C8 aromatics and C8+ hydrocarbons. The method further includes fractioning the bottom fraction and forming a heavy overhead fraction including the remaining C8 aromatics. Also, the method includes combining the sidedraw fraction and the heavy overhead fraction to form a combined stream having a C9 aromatics composition of from about 0.1 wt % to about 5 wt % about 2 wt % of a total weight of the combined stream.

Abstract: Methods and systems are provided for separating a selected xylene isomer. The method includes separating a feed stream including a plurality of aromatic hydrocarbons into a first stream including toluene and isomers of xylene, and a second stream including isomers of xylene. The method further includes separating the first stream into a third stream including toluene and a fourth stream including isomers of xylene. The method further includes combining the second stream and the third stream in an adsorptive separation unit including an adsorbent configured to adsorb the selected xylene isomer from the second stream. The third stream desorbs the selected xylene isomer to produce a fifth stream including the selected xylene isomer and toluene and a sixth stream including non-selected xylene isomers and toluene. Still further, the method includes separating the sixth stream into a seventh stream including the non-selected xylene isomers and the third stream including toluene.

Abstract: Methods and systems are provided for producing a desired xylene isomer. The method includes adsorbing the desired xylene isomer from a mixed xylene stream in an adsorbent chamber. The desired xylene isomer is desorbed with a desorbent to produce an extract stream with the desired xylene isomer and the desorbent, where the desorbent has a lower boiling point than the desired xylene isomer. The extract stream is fractionated in an extract fractionator to produce a low pressure extract overhead stream with gaseous desorbent. The low pressure extract overhead stream is pressurized to produce a high pressure extract overhead stream with a temperature greater than an extract reboiler temperature. The high pressure extract overhead stream is condensed in an extract process reboiler, and produces a liquid extract overhead stream.

Abstract: Embodiments of processes for producing propylene from paraffins are provided. The process comprises the steps of combining an effluent that comprises propylene and propane from a paraffin dehydrogenation reactor with an offgas stream that comprises propane to form a combined effluent stream. The combined effluent stream is separated into a propylene product stream and a propane-rich recycle stream. The propane-rich recycle stream is introduced to the paraffin dehydrogenation reactor operating at dehydrogenation conditions to convert propane in the propane-rich recycle stream to propylene.

Abstract: Apparatuses and methods are provided for isolating C8 aromatics from hydrocarbon streams. In one embodiment, a method for separating C8 aromatics from a hydrocarbon stream includes introducing the hydrocarbon stream to a fractionation column at a feed point. Further, the method includes fractionating the hydrocarbon stream in the fractionation column. Also, the method includes withdrawing a sidedraw fraction from the fractionation column at a draw point located above the feed point, wherein the sidedraw fraction includes C8 aromatics.

Abstract: Apparatuses and methods are provided for forming C8 aromatic streams with selected amounts of C9 aromatics. In one embodiment, a method for forming a C8 aromatic stream with a selected amount of C9 aromatics includes fractionating a hydrocarbon stream including C8 and C9 aromatics into a sidedraw fraction and a bottom fraction. The sidedraw fraction includes a portion of the C8 aromatics and a portion of the C9 aromatics. The bottom fraction includes remaining C8 aromatics and C8+ hydrocarbons. The method further includes fractioning the bottom fraction and forming a heavy overhead fraction including the remaining C8 aromatics. Also, the method includes combining the sidedraw fraction and the heavy overhead fraction to form a combined stream having a C9 aromatics composition of from about 0.1 wt % to about 5 wt % about 2 wt % of a total weight of the combined stream.

Abstract: Methods and systems are provided for separating a selected xylene isomer. The method includes separating a feed stream including a plurality of aromatic hydrocarbons into a first stream including toluene and isomers of xylene, and a second stream including isomers of xylene. The method further includes separating the first stream into a third stream including toluene and a fourth stream including isomers of xylene. The method further includes combining the second stream and the third stream in an adsorptive separation unit including an adsorbent configured to adsorb the selected xylene isomer from the second stream. The third stream desorbs the selected xylene isomer to produce a fifth stream including the selected xylene isomer and toluene and a sixth stream including non-selected xylene isomers and toluene. Still further, the method includes separating the sixth stream into a seventh stream including the non-selected xylene isomers and the third stream including toluene.

Abstract: Methods and systems are provided for producing a desired xylene isomer. The method includes adsorbing the desired xylene isomer from a mixed xylene stream in an adsorbent chamber. The desired xylene isomer is desorbed with a desorbent to produce an extract stream with the desired xylene isomer and the desorbent, where the desorbent has a lower boiling point than the desired xylene isomer. The extract stream is fractionated in an extract fractionator to produce a low pressure extract overhead stream with gaseous desorbent. The low pressure extract overhead stream is pressurized to produce a high pressure extract overhead stream with a temperature greater than an extract reboiler temperature.

Abstract: Processes for increasing overall aromatics and xylenes yield in an aromatics complex are provided. A C8+ aromatics stream from an aromatics-rich reformate is separated into a C8 aromatics fraction and a C9+ aromatics fraction comprising higher alkyl group-substituted C9 and C10 aromatics. The C9+ aromatics fraction is separated into a lighter boiling, higher alkyl group-substituted C9 or C9/C10 aromatics fraction and a heavier boiling, C10+ or C11+ aromatics fraction. The lighter boiling, higher alkyl group-substituted C9 or C9/C10 aromatics fraction is isomerized to convert a portion of the higher alkyl group-substituted C9 or C9/C10 aromatics therein into methyl-enriched C9 aromatics or methyl-enriched C9/C10 aromatics. The methyl-enriched C9+ aromatics stream comprising the methyl-enriched C9+ aromatics stream or the methyl-enriched C9/C10 aromatics is transalkylated with a toluene-containing stream.

Abstract: Embodiments of processes for producing propylene from paraffins are provided. The process comprises the steps of combining an effluent that comprises propylene and propane from a paraffin dehydrogenation reactor with an offgas stream that comprises propane to form a combined effluent stream. The combined effluent stream is separated into a propylene product stream and a propane-rich recycle stream. The propane-rich recycle stream is introduced to the paraffin dehydrogenation reactor operating at dehydrogenation conditions to convert propane in the propane-rich recycle stream to propylene.

Abstract: Processes for increasing overall aromatics and xylenes yield in an aromatics complex are provided. A C8+ aromatics stream from an aromatics-rich reformate is separated into a C8 aromatics fraction and a C9+ aromatics fraction comprising higher alkyl group-substituted C9 and C10 aromatics. The C9+ aromatics fraction is separated into a lighter boiling, higher alkyl group-substituted C9 or C9/C10 aromatics fraction and a heavier boiling, C10+ or C11+ aromatics fraction. The lighter boiling, higher alkyl group-substituted C9 or C9/C10 aromatics fraction is isomerized to convert a portion of the higher alkyl group-substituted C9 or C9/C10 aromatics therein into methyl-enriched C9 aromatics or methyl-enriched C9/C10 aromatics. The methyl-enriched C9+ aromatics stream comprising the methyl-enriched C9+ aromatics stream or the methyl-enriched C9/C10 aromatics is transalkylated with a toluene-containing stream.