Abstract: The present invention relates to a method for converting a feed mixture comprising an aromatic C8 mixture of xylenes and ethylbenzene in which the para-xylene content of the xylene portion of the feed is less than equilibrium to produce a product mixture of reduced ethylbenzene content and a greater amount of para-xylene, which method comprises contacting the feed mixture at conversion conditions with a first catalyst having activity for the conversion of ethylbenzene, and with a second catalyst having activity for the isomerization of a xylene.

Abstract: The present invention relates to a method for converting a feed mixture comprising an aromatic C8 mixture of xylenes and ethylbenzene in which the para-xylene content of the xylene portion of the feed is less than equilibrium to produce a product mixture of reduced ethylbenzene content and a greater amount of para-xylene, which method comprises contacting the feed mixture at conversion conditions with a first catalyst having activity for the conversion of ethylbenzene, and with a second catalyst having activity for the isomerization of a xylene.

Abstract: Processes for recovering paraxylene from at least two feedstreams containing xylene isomers. The process includes directing to a paraxylene recovery zone comprising at least one crystallization zone, a paraxylene-lean feedstream having a paraxylene to total xylene isomer ratio of 0.50 or less, and also directing to the paraxylene recovery zone, a paraxylene-rich feedstream having a paraxylene to total xylene isomer ratio of greater than 0.50. A paraxylene-containing product stream is recovered from the paraxylene recovery zone having a paraxylene to total xylene isomer ratio greater than that of the paraxylene-rich feedstream. The process provides improvements in paraxylene recovery efficiency and/or cost effectiveness.

Abstract: Processes and apparatus are disclosed for the energy efficient separation of the effluent from a TOL/A9+ transalkylation reactor. The apparatus includes a reboiled prefractionation column and a sidedraw tower that produces: 1) an overhead stream including unreacted toluene, 2) a stream including unreacted C9+ aromatics, a portion of which stream may be recycled to the reactor; and 3) a sidedraw stream including C8 aromatics that may be directed to a crystallization or selective adsorption paraxylene separation unit for recovery o a paraxylene product.

Abstract: The present invention relates to a method for converting a feed mixture comprising an aromatic C8 mixture of xylenes and ethylbenzene in which the para-xylene content of the xylene portion of the feed is less than equilibrium to produce a product mixture of reduced ethylbenzene content and a greater amount of para-xylene, which method comprises contacting the feed mixture at conversion conditions with a first catalyst having activity for the conversion of ethylbenzene, and with a second catalyst having activity for the isomerization of a xylene.

Abstract: Processes for the energy efficient recycle of naphthenes in a paraxylene manufacturing process comprise partially condensing a reactor effluent and using a sidedraw tower apparatus. The naphthenes are efficiently separated into the sidedraw stream of the sidedraw tower apparatus. At least a portion of the sidedraw stream is directed to a paraxylene recovery section that produces a paraxylene product and a paraxylene lean stream comprising essentially all of the naphthenes in the sidedraw stream directed to the paraxylene recovery section. The paraxylene lean stream is recycled back to the reactor thereby preventing excessive loss of naphthenes from the processes.

Abstract: Processes and apparatus are disclosed for the energy efficient separation of the effluent from a TOL/A9+ transalkylation reactor. The apparatus includes a reboiled prefractionation column and a sidedraw tower that produces: 1) an overhead stream including unreacted toluene, 2) a stream including unreacted C9+ aromatics, a portion of which stream may be recycled to the reactor; and 3) a sidedraw stream including C8 aromatics that may be directed to a crystallization or selective adsorption paraxylene separation unit for recovery o a paraxylene product.

Abstract: Processes for the energy efficient recycle of naphthenes in a paraxylene manufacturing process comprise partially condensing a reactor effluent and using a sidedraw tower apparatus. The naphthenes are efficiently separated into the sidedraw stream of the sidedraw tower apparatus. At least a portion of the sidedraw stream is directed to a paraxylene recovery section that produces a paraxylene product and a paraxylene lean stream comprising essentially all of the naphthenes in the sidedraw stream directed to the paraxylene recovery section. The paraxylene lean stream is recycled back to the reactor thereby preventing excessive loss of naphthenes from the processes.

Abstract: Methods for making and using a catalytic composition useful in the hydrocarbon conversion reactions. The catalytic composition is made from an alumina sol that is prepared by dispersing a hydrated alumina in an aqueous medium. The alumina sol is mixed with a boron-containing molecular sieve. Catalytic compositions prepared in this manner avoid the disadvantages of preparing alumina sols via the Heard process.

Abstract: A process for recovering paraxylene from a substantially hydrocarbon feedstock. The recovery comprises cooling the hydrocarbon feedstock in at least one refrigerated crystallization stage that is indirectly refrigerated by evaporating at least a portion of a substantially liquid stream comprising ammonia. The crystallization stage may also be cooled by an ethylene refrigerant, which has been cooled by heat exchange with a substantially liquid stream comprising ammonia. The process further comprises a series of cooling substeps. This invention is also directed to an ammonia absorption refrigeration process powered by an enthalpy source from or near a paraxylene recovery unit.

Abstract: An autothermal cracking process for production and recovery of olefins. The process comprises feeding a substantially hydrocarbon feedstock and an oxygen-containing gas to an autothermal cracker to provide a hydrocarbon product stream comprising olefins. A waste enthalpy source generated by said autothermal cracking process is used to at least partially drive an ammonia absorption refrigeration system to provide chilling for at least one process stream in the separation and/or purification of olefins from the hydrocarbon product stream.

Abstract: A process for recovering paraxylene from a substantially hydrocarbon feedstock. The recovery .comprises cooling the hydrocarbon feedstock in at least one refrigerated crystallization stage that is indirectly refrigerated by evaporating at least a portion of a substantially liquid stream comprising ammonia. The crystallization stage may also be cooled by an ethylene refrigerant, which has been cooled by heat exchange with a substantially liquid stream comprising ammonia. The process further comprises a series of cooling substeps. This invention is also directed to an ammonia absorption refrigeration process powered by an enthalpy source from or near a paraxylene recovery unit.

Abstract: Improved catalysts and a method for preparing improved catalysts suitable for the selective dehydrogenation of dehydrogenatable organic compounds which method comprises contacting a composition comprising a platinum group metal component and a halide component on an alumina support material with an aqueous alkaline solution of an alkali metal salt, the amount of solution being in excess of the amount absorbed by the composition; partitioning the composition from remaining solution to form a treated composition and a filtrate containing solubilized halide removed from the composition; and drying the treated composition to form the catalysts.

Abstract: A process for selectively dehydrogenating organic compounds, and particularly for dehydrogenating dimethyltetralins to dimethylnaphthalenes, by contacting the organic compound at an elevated temperature with a catalyst prepared by treating a composition comprising an alumina support material and platinum group metal with an excess amount of an alkaline solution of an alkali metal salt.

Abstract: A catalyzed process for the isomerization of a xylene-containing stream containing a major amount of ethylbenzene under supercritical temperature and pressure which contacts the stream under supercritical conditions with a catalyst and subsequently reduces the temperature of the isomerization product at a pressure above the critical pressure.

Abstract: Gallium-containing, crystalline silicate molecular sieves in which substantially all of the gallium occupies molecular sieve lattice positions or is intimately associated with the crystal lattice of the silicate sieve when composited into a silica matrix are shown to form catalyst compositions having superior properties for the catalytic, liquid-phase isomerization of a xylene-containing stream containing a minor amount of ethylbenzene to a product mixture rich in paraxylene.

Abstract: An improved process employing a supported, platinum-containing, crystalline, silicate molecular sieve catalyst composition effective in removing ethylbenzene from unextracted xylene feeds during isomerization, primarily by hydrodeethylation, and also the primarily C.sub.9 paraffins and naphthenes. Choosing (1) a set of process conditions within narrow ranges of temperature T, total pressure P, and hydrogen to hydrocarbon mol ratio H/HC such that Z, which is defined as a function of T, P and H/HC, is less than about 0.01, and (2) a platinum-containing catalyst composition, greatly reduces the feed C.sub.9 paraffins and naphthenes content during isomerization, removes most of the ethylbenzene by hydrodeethylation to ethane and benzene, and minimizes xylene loss to hydrogenation and cracking, all without substantially changing the excellent isomerization properties of the sieve catalyst composition.

Abstract: Recovery of germanium from the effluent of optical fiber manufacturing processes depends on the realization that the germanium is to a substantial extent in gaseous form. Thus, to separate the germanium effectively appropriate measures are taken to separate not only particulate matter but also gaseous germanium compounds. This separation is done through among other steps an appropriate solvation and precipitation to remove the gaseous germanium material.