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.
Abstract:
Aromatic conversion processes employing zeolite Y, zeolite omega and zeolite beta molecular sieve catalyst. A feed stock containing at least one aromatic compound and having water entrained therein is passed to a dehydration zone. In the dehydration zone, water is removed to provide a dehydrated feed stock of a water content no more than 100 ppm, preferably 50 ppm or less. The dehydrated feed stock is then supplied to the reaction zone containing the molecular sieve catalyst selected from the group consisting of zeolite Y, zeolite omega, and zeolite beta. The reaction zone is operated at temperature and pressure conditions to maintain the reactor contents in the liquid phase and also sufficient to cause the conversion reaction to proceed in the presence of the catalyst. Specific conversion processes include the ethylation of benzene under liquid-phase conditions to produce ethylbenzene and the transalkylation of a feed stock containing a mixture of a polyalkylbenzene component and a benzene component to produce a disproportionation product comprising a monoalkylbenzene.
Abstract:
Alkylation systems and methods of minimizing alkylation catalyst regeneration are discussed 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 first preliminary alkylation catalyst disposed therein to form a first output stream. The first preliminary alkylation catalyst generally includes a Y zeolite. The 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:
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:
A method for the dehydrogenation of isoamylene to isoprene at pressures less than atmospheric utilizing a dehydrogenation catalyst is disclosed. Embodiments involve operating the dehydrogenation reactor at a pressure of 1,000 mbar or less.
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.