Abstract:
Methods and systems for petrochemical feedstream purification are described herein. The methods generally include providing a petrochemical feedstock, wherein the petrochemical feedstock includes a concentration of polar impurities, contacting the petrochemical feedstock with a washing agent to remove at least a portion of the polar impurities therefrom, separating the washing agent from the petrochemical feedstock to form a purified feedstock and passing the purified feedstock to a petrochemical process. In one embodiment, the petrochemical feedstock includes benzene and the washing agent includes water.
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:
Process for the catalytic dehydrogenation of ethylbenzene in which a feedstock containing ethylbenzene and steam is supplied into the inlet of a tubular reactor containing a dehydrogehation 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 styrene 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.
Abstract:
An alkylation/transalkylation process involving vapor phase alkylation of a benzene feedstock in a multi-stage alkylation zone having a plurality of series connected catalyst beds containing a pentasil aromatic alkylation catalyst, such as silicalite, coupled with intermediate separation and recirculation steps and liquid phase transalkylation over a transalkylation catalyst comprising a molecular sieve having a pore size greater than the pore size of the silicalite. The benzene containing feedstock is supplied to the multi-stage alkylation reaction zone along with a C.sub.2 -C.sub.4 alkylating agent operated under temperature and pressure conditions to maintain the benzene in the gas phase. Alkylated product is recovered from the alkylation zone and supplied to a benzene recovery zone for the separation of the benzene from the alkylation product. Benzene from the benzene recovery zone is recycled to the reaction zone. A higher boiling bottom fraction containing a mixture of monoalkylated and polyalkylated aromatic components is supplied to a secondary separation zone from which a monoalkylated aromatic component, e.g. ethylbenzene, is recovered overhead with a heavier polyalkylated aromatic recovered as a bottom fraction. The bottom fraction may be applied to a tertiary separation zone.
Abstract:
A process is provided for the disproportionation of a toluene feedstock over a metal promoted mordenite catalyst. The catalyst may contain between 1.0-1.5 weight percent nickel. The toluene feedstock is supplied to the reaction zone and into contact with the catalyst. The reaction zone is operated under disproportionation conditions. During disproportionation, heavy aromatic reformates, in concentration of at least 4 weight percent, are introduced into the reaction zone. Disproportionation product containing benzene and xylene is continuously withdrawn. The addition of the heavy aromatic reformate does not adversely affect toluene conversion rates, product selectivity to benzene, catalyst activity or catalyst life. Moreover, production of xylenes increase at the expense of production of heavies.
Abstract:
A method for the dehydrogenation of hydrocarbons to alkenes, such as n-pentene to piperylene and n-butane to butadiene at pressures less than atmospheric utilizing a dehydrogenation catalyst are disclosed. Embodiments involve operating the dehydrogenation reactor at a pressure of 1,000 mbar or less.
Abstract:
Process for the production of an isoprene containing rubber compound by dehydrogenation of an isoamylene containing feedstock supplied to a dehydrogenation reactor containing a particulate dehydrogenation catalyst comprising iron and potassium and having a pore diameter of at least 500 nanometers. The dehydrogenation reactor is operated at a temperature of at least 570° C. to dehydrogenate the isoamylene to produce isoprene. The product containing isoprene and unreacted isoamylene is recovered from the dehydrogenation reactor. Isoprene is polymerized to produce an isoprene containing rubber product. An unreacted feed component containing isoamylene is separated from the rubber product and recycled to the dehydrogenation reactor.
Abstract:
Apparatus, methods and systems useful for removing phenylacetylene from crude styrene feedstock are disclosed. Generally the processes and systems comprise the catalytic reduction of phenylacetylene to produce styrene via injection of a phenylacetylene reducing agent, such as hydrogen. A phenylacetylene reduction catalyst preferred herein comprises palladium on a calcium aluminate carrier, wherein the catalyst comprises less than 0.3 weight percent palladium.
Abstract:
A process is disclosed which provides for the reduction of phenylacetylene levels in styrene monomer feedstreams, which process utilizes a normal styrene inhibitor additive, such as an hydroxylamine, injected into the styrene monomer feedstream immediately upstream of the phenylacetylene reduction reactor.
Abstract:
The present invention addresses heat integration in an alkylation/transalkylation process involving alkylation of an aromatic substrate with a C.sub.2 -C.sub.4 alklating agent coupled with separation to recover a monoalkylated aromatic product and liquid phase transalkylation of a polyalkylated product. Aromatic feedstock and a C.sub.2 -C.sub.4 alkylating agent are supplied to an alkylation reaction zone which is operated to produce an alkylated product. The output from the alkylation reaction zone initially travels through an arrangement of heat exchangers. From there, the alkylation effluent passes into the first separation zone which is operated to produce a lower boiling fraction comprising the aromatic substrate, which may be recycled to the alkylation reaction zone, and a higher boiling fraction comprising a mixture of monoalkylated and polyalkylated aromatics. This lower boiling fraction first travels back through portions of the heat exchanger arrangement on the way to recycle into the alkylation zone. The higher boiling fraction of the first separation zone is supplied to a secondary separation zone to produce a second lower boiling fraction comprising the desired monoalkylated product and a higher boiling fraction comprising polyalkylated product. At least a portion of the higher boiling polyalkylated fraction passes through a portion of the heat exchanger arrangement into a transalkylation reaction zone containing a molecular sieve transalkylation catalyst operated under liquid phase conditions to cause disproportionation of the polyalkylated fraction to arrive at a disproportionation product having a reduced polyalkylated aromatic content and an enhanced monoalkylated aromatic content.