Abstract:
Alkylation systems and methods of minimizing alkylation catalyst regeneration are described herein. The alkylation systems generally include a preliminary alkylation system adapted to receive an input stream including an alkyl aromatic hydrocarbon and contact the input stream with a preliminary alkylation catalyst disposed therein to form a first output stream. The preliminary alkylation catalyst generally includes a zeolite catalyst having a SiO2/Al2O3 ratio of less than about 25. The alkylation systems further include a first alkylation system adapted to receive the first output stream and contact the first output stream with a first alkylation catalyst disposed therein and an alkylating agent to form a second output stream.
Abstract translation:本文描述了使烷基化催化剂再生最小化的烷基化系统和方法。 烷基化系统通常包括适于接收包含烷基芳族烃的输入流并将输入流与设置在其中的预置烷基化催化剂接触以形成第一输出流的初步烷基化系统。 初步烷基化催化剂通常包括SiO 2 / Al 2 O 3比小于约25的沸石催化剂。烷基化系统还包括适于接收第一输出流并将第一输出流与置于其中的第一烷基化催化剂接触的第一烷基化系统 和烷基化剂以形成第二输出流。
Abstract:
Process for the catalytic dehydrogenation of a C2 or C3 alkyl aromatic in which a feedstock containing the alkyl aromatic and steam is supplied into the inlet of a tubular reactor containing a dehydrogenation catalyst. Within the reactor, the feedstock flows through at least a portion of the reactor along a spiral flow path extending longitudinally of the reactor. The resulting vinyl aromatic product is then recovered from a downstream or outlet section of the reactor. The spiral flow path through which the feedstock is passed is located at least adjacent the inlet side of the reactor and at least a portion of the spiral flow path contains a particulate dehydrogenation catalyst. The spiral flow path may extend throughout a major portion of the elongated tubular reactor and may contain a particulate dehydrogenation catalyst in a substantial portion there. The feedstock containing the alkyl aromatic and steam is supplied into a plurality of tubular reactors located within the interior of a dehydrogenation reactor vessel and is arranged in a parallel relationship in which the tubular reactors are spaced laterally from one another and from the interior wall of the reaction vessel.
Abstract:
The alkylation of benzene-containing feedstock over a zeolite beta alkylation catalyst which is formulated with a silica binder and has an average regeneration coefficient of at least 95% for at least three regenerations. The alkylation reaction is carried out in the liquid phase or supercritical region with a C2-C4 alkylating agent, specifically ethylene. The catalyst exhibits a regeneration coefficient of at least 95% after ethylation of the benzene with ethylene at a benzene/ethylene mole ratio of less than 10. The ethylation of benzene occurs at an initial designated primary activity. The operation of the reaction zone is continued until the activity of the catalyst for the ethylation of benzene decreases by a value of at least 0.1% and not more 1% from the initial designated primary activity. The operation of the reaction for alkylation is terminated and a regeneration procedure is instituted in which the catalyst is regenerated in an oxidizing environment at an average temperature of no more than 500° C. At the conclusion of the regeneration procedure, the operation of the alkylation zone is reinstituted with the reaction zone again operated under conditions as described above followed by regeneration.
Abstract:
Process for the production of ethylbenzene by alkylation over a silicalite alkylation catalyst with subsequent transalkylation of diethylbenzene with the alkylation catalyst and conditions selected to retard xylene production and also heavies production. Benzene and ethylene are applied to a multi-stage alkylation reaction zone having a plurality of series-connected catalyst beds containing silicalite of a predominantly monoclinic symmetry having a silica/alumina ratio of at least 275. Gas-phase ethylation of benzene is at a flow rate to provide a space velocity of benzene over the catalyst to produce a xylene concentration of about 600 ppm or less of the ethylbenzene content. Periodically the space velocity may be increased to a value which is greater than the space velocity associated with a minimum concentration of diethylbenzene in the alkylation product such that diethylbenzene production is enhanced while minimizing any attendant transalkylation reactions within the alkylation reaction zone. The alkylation reactor output is applied to an intermediate recovery zone for the separation and recovery of ethylbenzene with the recovery of a polyalkylated aromatic component which is supplied along with benzene to a transalkylation reaction zone for disproportionation to provide a reduced diethylbenzene content and an enhanced ethylbenzene content. A specific monoclinic silicalite alkylation catalyst has a silica/alumina ratio of at least 300 and has a crystal size of less than one micron.
Abstract:
Ethylbenzene is produced by alkylation over a split load of monoclinic silicalite alkylation catalysts having different silica/alumina ratios. A feedstock containing benzene and ethylene is applied to a multi-stage alkylation reaction zone having a plurality of series-connected catalyst beds. At least one catalyst bed contains a first monoclinic silicalite catalyst having a silica/alumina ratio of at least 275. At least one other catalyst bed contains a second monoclinic silicalite catalyst having a silica/alumina ratio of less than about 275. The alkylation reaction zone is operated at temperature and pressure conditions in which the benzene is in a gaseous phase to cause gas-phase alkylation of the aromatic substrate in the presence of the monoclinic silicalite catalysts to produce an alkylation product. The alkylation product is then withdrawn from the reaction zone for separation and recovery. The use of the split load of catalyst allows a higher purity ethylbenzene product to be produced at improved efficiencies than if only one of the catalysts were used by itself.
Abstract:
A process for the transalkylation of polyalkylated aromatic compounds over a high porosity zeolite-Y molecular sieve having a surface area of no more than 500 m2/g. A feedstock comprising a polyalkylated aromatic component, including polyalkylbenzenes in which the predominant alkyl substituents contain from 2 to 4 carbon atoms, is supplied to a transalkylation reaction zone containing the high porosity zeolite-Y catalyst. Benzene is also supplied to the transalkylation zone, and the reaction zone is operated under temperature and pressure conditions to maintain the polyalkylated aromatic component in the liquid phase and which are effective to cause disproportionation of the polyalkylated aromatic component to arrive a disproportionation product having a reduced polyalkylbenzene content and an enhanced monoalkylbenzene content. An alkylation reaction zone is provided which contains a molecular sieve aromatic alkylation catalyst having an average pore size which is less than the average pore size of the average pore size of the high porosity zeolite-Y. A feedstock comprising benzene in a C2-C4 alkylating agent is supplied to the alkylation reaction zone which is operated under conditions to produce alkylation of the benzene by the alkylating agent in the presence of the molecular sieve alkylation catalyst. The alkylation product from the alkylation reaction zone is supplied to an intermediate recovery zone for the separation and recovery of a monoalkylbenzene, e.g. ethylbenzene, from the alkylation product; together with the recovery of a polyalkylated aromatic component employing a dialkylbenzene, e.g. diethylbenzene. The polyalkylated aromatic component is employed in at least a portion of the feedstream supplied to the transalkylation reactor.
Abstract:
A process for the production of ethylbenzene by the gas phase alkylation of benzene over a molecular sieve aromatic alkylation catalyst followed by liquid phase alkylation of the product of the gas phase alkylation. A feedstock containing benzene and ethylene is supplied to a first alkylation reaction zone containing a molecular sieve aromatic alkylation catalyst. The reaction zone is operated at temperature and pressure conditions to cause gas phase ethylation of the benzene with the production of an alkylation product comprising a mixture of ethylbenzene and polyalkylated aromatic components including diethylbenzene. The output from the first alkylation reaction zone is supplied, at least in part, to a second alkylation zone which is operated in the liquid phase or in the supercritical region followed by supply to an intermediate recovery zone for the separation and recovery of ethylbenzene and a polyalkylated aromatic compound component including diethylbenzene.
Abstract:
A process for the production of ethylbenzene by the alkylation of benzene over a molecular sieve aromatic alkylation catalyst followed by transalkylation of polyalkylated aromatic components and then liquid phase alkylation. A feedstock containing benzene and ethylene is supplied to a first alkylation reaction zone containing a molecular sieve aromatic alkylation catalyst. The reaction zone is operated at temperature and pressure conditions to cause gas phase ethylation of the benzene with the production of an alkylation product comprising a mixture of ethylbenzene and polyalkylated aromatic components including diethylbenzene with xylene present in only small amounts. The output from the alkylation reaction zone is supplied to an intermediate recovery zone for the separation and recovery of ethybenzene, a polyalkylated aromatic compound component including diethylbenzene. At least a portion of the polyalkylated component is supplied along with benzene to a transalkylation reaction zone operated in the liquid phase. Disproportionation product from the transalkylaton reaction zone is supplied to a second alkylation zone containing a molecular sieve aromatic alkylation catalyst. Ethylene is also supplied to the second alkylation zone which is operated under temperature and pressure conditions to cause liquid phase ethylation of the benzene. The alkylation product from the second alkylation zone is supplied to the aforementioned intermediate recovery zone.
Abstract:
Process for the production of ethylbenzene by alkylation over a silicalite alkylation catalyst with the subsequent transalkylation of diethylbenzene with the alkylation catalyst and conditions selected to retard xylene production and also heavies production. A feedstock containing benzene and ethylene is applied to a multi-stage alkylation reaction zone having a plurality of series-connected catalyst beds containing a pentasil molecular sieve alkylation catalyst which is silicalite of a predominantly monoclinic symmetry having a silica/alumina ratio of at least 275. The feedstock is supplied to the alkylation reaction zone to cause gas-phase ethylation of benzene at a flow rate to provide a space velocity of benzene over the catalyst to produce a xylene concentration in the product of about 600 ppm or less based upon the ethylbenzene content. Periodically the space velocity may be increased to a value which is greater than the space velocity associated with a minimum concentration of diethylbenzene in the alkylation product such that diethylbenzene production is enhanced while minimizing any attendant transalkylation reactions within the alkylation reaction zone. This is accompanied by a relatively low xylene content in the product, specifically no more than 600 ppm based upon the ethylbenzene in the product. The output from the alkylation reactor is applied to an intermediate recovery zone for the separation and recovery of ethylbenzene with the recovery of a polyalkylated aromatic component which is supplied along with benzene to a transalkylation reaction zone where the polyalkylated aromatic fraction is subject to disproportionation to provide a reduced diethylbenzene content and an enhanced ethylbenzene content.
Abstract:
Alkylation systems and methods of minimizing alkylation catalyst regeneration are described herein. The alkylation systems generally include a preliminary alkylation system adapted to receive an input stream including an alkyl aromatic hydrocarbon and contact the input stream with a preliminary alkylation catalyst disposed therein to form a first output stream. The preliminary alkylation catalyst generally includes a zeolite catalyst having a SiO2/Al2O3 ratio of less than about 25. The alkylation systems further include a first alkylation system adapted to receive the first output stream and contact the first output stream with a first alkylation catalyst disposed therein and an alkylating agent to form a second output stream.
Abstract translation:本文描述了使烷基化催化剂再生最小化的烷基化系统和方法。 烷基化系统通常包括适于接收包含烷基芳族烃的输入流并将输入流与设置在其中的预置烷基化催化剂接触以形成第一输出流的初步烷基化系统。 初步烷基化催化剂通常包括SiO 2 / Al 2 O 3比小于约25的沸石催化剂。烷基化系统还包括适于接收第一输出流并将第一输出流与置于其中的第一烷基化催化剂接触的第一烷基化系统 和烷基化剂以形成第二输出流。