Selective removal of non-aromatic hydrocarbons from a xylene isomerization process for para-xylene production is accomplished using a membrane unit positioned within a xylene recovery loop. The membrane unit may include a one-stage or multi-stage (e.g., two-stage) membrane system and may be configured to separate a membrane unit product stream from a non-aromatics rich stream, which can be removed from the xylene recovery loop. The membrane unit may have a xylene permeance of about 60 gm/m2/hr/psi and a xylene to non-aromatic permeance ratio of about 15.

A process, a system, and an apparatus for separation of an oxygenate from a stream is provided. More specifically, a stream comprising the oxygenate is introduced to a quench tower along with a caustic outlet stream comprising a metal salt. Contact between the oxygenate and the metal salt results in conversion of a portion of the oxygenate into a derivative salt. The derivative salt and unconverted oxygenate are condensed by quenching and substantially removed from the quench tower as an oxygenate outlet stream. The gaseous components of the stream, minus a substantial portion of the oxygenate, are removed from the quench tower as a quench outlet stream.

Embodiments of apparatuses and methods for reforming of hydrocarbons including recovery of products are provided. In one example, a method comprises separating a reforming-zone effluent into a net gas phase stream and a liquid phase hydrocarbon stream. The net gas phase stream is separated for forming an H.sub.2-rich stream and a first liquid phase hydrocarbon stream. The H.sub.2-rich stream may be contacted with an adsorbent to form an H.sub.2-ultra rich stream and a gas stream. C.sub.3/C.sub.4 hydrocarbons are absorbed from the gas stream with the liquid phase hydrocarbon stream. The gas stream may be contacted with an H.sub.2/hydrocarbon separation membrane to separate the PSA tail gas stream and form an H.sub.2-rich permeate stream and an H.sub.2 depleted non-permeate residue stream.

Disclosed is a method for removing benzo[α]pyrene from a liposoluble natural extract. The method of the present invention comprises adding a suitable solvent to a crude natural extract product so as to obtain a mixed material; heating the mixed material, stirring until uniform, cooling and layering, and then separating the upper layer from the lower layer so as to obtain a precipitate and a filtrate; washing the precipitate with a small amount of a solvent so as to obtain a washed product and a washing solution; removing the solvent from the washed product at a low temperature so as to obtain a finished product; and directly recycling the filtrate and the washing solution as solvents. The present method achieves the purification of the crude natural extract product and the removal of benzo[α]pyrene in one step, and is a novel method which is simple, highly efficient, feasible and easy for industrial applications.

Disclosed is a method for removing benzo[α]pyrene from a liposoluble natural extract. The method of the present invention comprises adding a suitable solvent to a crude natural extract product so as to obtain a mixed material; heating the mixed material, stirring until uniform, cooling and layering, and then separating the upper layer from the lower layer so as to obtain a precipitate and a filtrate; washing the precipitate with a small amount of a solvent so as to obtain a washed product and a washing solution; removing the solvent from the washed product at a low temperature so as to obtain a finished product; and directly recycling the filtrate and the washing solution as solvents. The present method achieves the purification of the crude natural extract product and the removal of benzo[α]pyrene in one step, and is a novel method which is simple, highly efficient, feasible and easy for industrial applications.

A method for producing a stream of propylene and associated facility are described. The method includes: an introduction of a feed cut rich in C4 and/or C5 hydrocarbons, and at least one cut rich in ethylene into a metathesis reactor; an introduction of a metathesis product in a deethylenizer; a production of an overhead stream rich in ethylene and a feed stream; an introduction of the feed stream into a depropylenizer and recovery of a bottom stream containing C4+ hydrocarbons; a recovery, from an overhead stream of the depropylenizer, of the propylene stream; a lateral withdrawal of a recycle stream and return of the recycle stream to the metathesis reactor; a lateral draw-off, in the depropylenizer, of a purge rich in C4 paraffinic hydrocarbons and/or rich in isobutene.

A method for the recovery paraxylene with reduced crystallization. Paraxylene is recovered from a mixture of C8 aromatic hydrocarbons in a pressure swing adsorption zone and a crystallization zone. The invention provides for lower throughput through the crystallization zone, resulting in lower capital costs, reduced electricity in operating separation equipment, as well as reduced refrigeration duty.

A facility and method for membrane permeation treatment of a feed gas flow containing at least methane and carbon dioxide that includes a compressor, a pressure measurement device, at least one valve, and first, second, third, and fourth membrane separation units for separation of CO.sub.2 from CH.sub.4 to permeates enriched in CO.sub.2 and retentates enriched in CH.sub.4, respectively. The at least one valve adjusts the number of membranes combined and connected to the flow of gas entering into at least one of the membrane separation units as a function of the pressure recorded by the pressure measurement device.

A method for operating an acetylene hydrogenation unit of a steam cracking system that integrates a fluidized catalytic dehydrogenation (FCDh) effluent from a fluidized catalytic dehydrogenation (FCDh) system may include separating a cracked gas from the steam cracking system into at least a hydrogenation feed comprising at least acetylene, CO, and hydrogen, introducing the FCDh effluent to the separation system, combining the FCDh effluent with the cracked gas upstream of the separation system, or both. The method may include hydrogenating acetylene in the hydrogenation feed. Elevated CO concentration in the hydrogenation feed due to the FCDh effluent may reduce a reaction rate of acetylene hydrogenation. The acetylene hydrogenation unit may operate at an elevated temperature relative to normal operating temperatures when the portion of the FCDh effluent is not integrated, such that a concentration of acetylene in the hydrogenated effluent is less than a threshold acetylene concentration.

A method for operating an integrated system for producing olefins may include contacting a hydrogenation feed with a first hydrogenation catalyst to produce a hydrogenated effluent, the hydrogenation feed including at least a portion of a first process effluent from a first olefin production process and at least a portion of a second process effluent from a second olefin production process. The hydrogenation feed may include at least hydrogen, ethylene, carbon monoxide, acetylene, methyl acetylene, and propadiene, and the first hydrogenation catalyst may be a hydrogenation catalyst having a temperature operating range of at least 40° C. The hydrogenated effluent may include methyl acetylene, propadiene, or both. The method may further include contacting at least a portion of the hydrogenated effluent with a second hydrogenation catalyst, which may cause hydrogenation of at least a portion of the methyl acetylene and propadiene to produce an MAPD hydrogenated effluent.