摘要:
A cyclic process for the purification of a diolefin hydrocarbon stream produced in a naphtha steam cracker to produce a high quality diolefin hydrocarbon stream having extremely low levels of acetylene over an extended period because of the ability to readily cyclically regenerate catalyst contained in an off-line selective hydrogenation reaction zone. The spent or partially spent catalyst is contacted with a stream containing naphtha and hydrogen to restore at least a portion of the fresh catalyst activity by the extraction of polymer compounds therefrom.
摘要:
An improved process for the production of alkylaromatic hydrocarbons is disclosed. Paraffinic hydrocarbons are dehydrogenated to yield an olefin-containing stream, which is later charged to an alkylation zone for reaction with an aromatic hydrocarbon in the presence of a solid alkylation catalyst. The olefin-containing stream is first passed through a selective hydrogenation zone in which diolefins are converted to monoolefins by contact with a selective catalyst. This increases the yield and the quality of the product alkylate by greatly reducing the production of biphenyl compounds and oligomers in the alkylation zone. Process efficiency is improved by passing unconverted paraffinic and monoolefinic hydrocarbons from the alkylation zone through another hydrogenation zone for the saturation of monoolefinic hydrocarbons and recycling the saturated stream to the dehydrogenation zone. The use of a solid alkylation catalyst can also allow the selective hydrogenation zone to be located downstream of the stripper for the dehydrogenation zone so that the effluent from the selective hydrogenation zone discharges directly into the alkylation zone.
摘要:
A process is disclosed for improving catalyst performance and yields in the manufacture of motor gasoline components. More particularly the process is directed to the removal of trace amounts of acetonitrile or acetone or propionitrile from a hydrocarbon feedstock such as a C.sub.4 -C.sub.6 product fraction from a fluid catalytic cracking unit, which may be used subsequently in an etherification process for the production of ethers such as MTBE and TAME. The hydrocarbon feedstock is passed to a water wash zone for the removal of the trace amounts of acetonitrile or acetone or propionitrile and the spent water comprising the nitriles is contacted with a nitrile-lean stream to regenerate the wash water. A portion of the spent water stream is withdrawn to reduce the nitrile level in the nitrile-lean water stream. The combined water wash, regeneration, and water recycle steps provide protection for the etherification zone catalyst with a significantly reduced requirement for wash water and spent wash water disposal.
摘要:
A regeneration process for reconditioning catalyst particles containing platinum by transferring the catalyst particles through a combustion zone and a reconditioning zone is disclosed. Drying of the catalyst particles and redispersion of the platinum occur simultaneously in a single reconditioning zone. Catalyst that enters the reconditioning zone is contacted countercurrently with a heated gas stream containing chlorine and oxygen. A low moisture content of the gas stream aids drying and allows the equilibrium reaction between hydrogen chloride and oxygen on the one hand, and water and chlorine on the other hand to be shifted to chlorine. This shift of the equilibrium reaction can be further improved by maintaining an oxygen-enriched environment within the reconditioning zone. By eliminating the need for separate drying and redispersion zones used previously, the regeneration apparatus is less expensive to build and the regeneration process is less expensive to operate.
摘要:
A method of operating a continuous process employing solid catalyst particles by means of charging a feedstock to a reactor and contacting the feedstock with a dense-phase moving bed of catalyst particles at conversion conditions in a reactor. A hydrogen-rich gas containing unsaturated hydrocarbon compounds is recovered from the reactor effluent and at least a portion is contacted with a hydrogenation catalyst to hydrogenate the olefins. The resulting hydrogenated hydrogen-rich gaseous stream is heated and used to supply heat to a vessel containing solid catalyst particles which are preheated and subsequently introduced into the reactor.
摘要:
A process for the dehydrogenation of a hydrocarbon selected from the group consisting of propane and butane in the presence of a catalyst comprising platinum and a carrier material. Reconditioning of catalyst particles containing platinum by transferring the catalyst particles through a combustion zone, a drying zone and a re-dispersion zone improves the process. Drying of the catalyst particles immediately after the combustion of coke improves the operation of a platinum re-dispersion zone. The lower moisture content in the re-dispersion zone allows the equilibrium reaction between hydrogen chloride and oxygen on the one hand, and water and chlorine on the other hand to be shifted to the production of chlorine. This shift of the equilibrium reaction can be further improved by maintaining an oxygen-enriched environment within the platinum re-dispersion zone. The use of a much lower chloride concentration in the re-dispersion zone reduces the emissions of hydrogen chloride from the regeneration zone.
摘要:
A process for the selective hydrogenation of trace quantities of acetylene compounds contained in a stream of diolefins to achieve extended on-stream performance by simultaneously contacting the selective catalyst with a diolefin feed, hydrogen and a polymer solvent.
摘要:
A low pressure catalytic distillation process for producing high purity ethyl tertiary butyl ether that contains less than 0.6 weight percent ethanol, and preferably less than 0.07 weight percent ethanol, has been developed. The high purity ethyl tertiary butyl ether is withdrawn directly from a catalytic distillation column. No downstream processing is necessary to remove excess ethanol from the ether product. A stream containing a significant amount of one or more inert azeotropic agents such as normal butane, isopentane, and isobutane is introduced along with the isobutylene and ethanol reactants into an etherification zone containing a catalytic distillation column. The catalytic distillation column is operated under low pressure conditions which result in the reaction of the ethanol with the isobutylene to form ethyl tertiary butyl ether. The inert azeotropic agent must be present at the inlet to the catalytic distillation column in an amount sufficient to azeotrope excess ethanol and cause the excess ethanol to distill into an overhead stream under the conditions of operation. The preferred azeotropic agent is isopentane. Excess ethanol forms an azeotrope with the azeotropic agent and is distilled with other hydrocarbons into an overhead stream. The ethyl tertiary butyl ether and no more than 0.6 weight percent ethanol are distilled into a bottoms stream and withdrawn directly from the catalytic distillation column.
摘要:
A process for reforming hydrocarbons has a regeneration process for reconditioning catalyst particles containing platinum that improves the process by transferring the catalyst particles through a combustion zone, a drying zone, a redispersion zone and a chloride uptake zone. Drying of the catalyst particles immediately after the combustion of coke improves the operation of a platinum redispersion zone and a chloride uptake zone. Separate platinum redispersion zones and chloride uptake zones are provided so that the dried catalyst that enters the platinum redispersion zone can be contacted with a high concentration of chlorine with a lower overall concentration of chloride compounds in the redispersion zone. The lower moisture content allows the equilibrium reaction between hydrogen chloride and oxygen on the one hand, and water and chlorine on the other hand to be shifted to the production of chlorine. This shift of the equilibrium reaction can be further improved by maintaining an oxygen-enriched environment within the platinum redispersion zone. Conversely, the chloride uptake zone would have essentially all the chloride contained therein in the form of hydrogen chloride. Only a relatively low concentration of hydrogen chloride is needed and the chloride uptake zone can be designed such that virtually all of the chloride compounds entering the zone are taken up with the catalyst. The uptake of virtually all the hydrogen chloride in the chloride uptake zone and the use of a much lower chloride concentration in the redispersion zone reduces the emissions of hydrogen chloride from the regeneration zone. Aside from improving the platinum redispersion, the overall reduction of chlorides in the platinum redispersion zone allows the elimination of a costly halogen circulation loop that was previously needed in a halogenation zone to maintain a sufficient chlorine concentration for redispersion of the platinum.