Phillips Petroleum Company

Charles C Chapman

Paul D Hann

Joe Van Pool

Rolland E Dixon

The reactor effluent hydrocarbon phase from an alkylation zone in which isoparaffin and olefin are contacted in the presence of HF catalyst to form alkylate product is treated by (1) separating a hydrocarbon phase from the reaction effluent; (2) separating the hydrocarbon phase in a first fractionator to produce a bottoms stream containing isoparaffin and alkylate; (3) flashing this bottoms stream to produce a flashed vapor enriched in isoparaffin and a flashed liquid enriched in alkylate; (4) subjecting this flashed liquid to a high pressure, high temperature fractionation in a second fractionator to produce isoparaffin overhead and alkylate from the kettle; and (5) passing the isoparaffin overhead as heat exchange fluid to at least one of (a) the indirect reboiling of the first fractionator kettle, (b) the indirect heating of the bottoms stream being fed from the first fractionator to the flashing step and (c) the indirect heating of the flashed liquid being fed to the second fractionator. In another embodiment, the hydrocarbon phase separated from the reaction effluent is further separated in a first fractionator to produce an overhead stream containing isoparaffin, alkane, HF, and organic fluoride impurities. This overhead stream is condensed and contacted with HF to remove the organic fluorides with the HF containing organic fluorides recycled to the reaction zone.

Separation of products of HF alkylation

The reactor effluent hydrocarbon phase from an alkylation zone in which isoparaffin and olefin are contacted in the presence of HF catalyst to form an alkylate product is treated by (1) separating a hydrocarbon phase from the reacton effluent; (2) separating the hydrocarbon phase in a fractionator to produce a bottoms stream containing isoparaffin, paraffin, and alkylate and an overhead stream containing HF, isoparaffin, and paraffin; (3) flashing this bottoms stream to produce a flashed vapor enriched in isoparaffin and a liquid enriched in alkylate as compared to the bottoms stream; (4) cooling this flashed vapor to produce a condensed liquid; and (5) indirectly contacting this condensed liquid with the overhead stream thereby cooling the overhead stream and heating the condensed liquid. In further embodiments of the invention flashing the condensed liquid thereby producing (a) a flashed vapor further enriched in paraffin which is then compressed and further treated to remove residual isoparaffin and (b) a liquid further enriched in isoparaffin which is recycled to the alkylation zone. In another embodiment of the invention the overhead stream is condensed by contact with the condensed liquid, pumped into contact with HF thereby removing organic fluorides, and is then subjected to treatment effecting separation of paraffin from isoparaffin.

A continuous process for alkylating an alkylatable hydrocarbon with an alkylating agent in the presence of an acid-type catalyst in which the alkylatable hydrocarbon is contacted with the alkylating agent in the presence of the catalyst at a temperature and for a time sufficient to alkylate the alkylatable hydrocarbon, the reaction product is separated into an alkylate product phase and a catalyst phase, containing catalyst-soluble oil, the catalyst phase is cooled to maintain a preselected temperature in the exothermic alkylation zone, the cooled catalyst phase is recycled to the alkylation reaction and a predetermined concentration of catalyst-soluble oil is maintained in the catalyst phase by at least periodically heating an alkylating agent to a temperature above the reaction temperature, contacting the heated alkylating agent with one of the separated recycle catalyst, separated rerun catalyst, fresh catalyst or mixture thereof and combining the resultant reaction product with separated recycle catalyst prior to the cooling of the separated recycle catalyst phase. A start-up procedure, in which the content of catalyst-soluble oil in the catalyst phase is brought up to the predetermined concentration, is also disclosed in which the reaction product of the heated alkylating agent and the catalyst is added to the catalyst phase. Apparatus for carrying out the above processes is also described.

Catalytic alkylation of hydrocarbons

Propylene and butylenes are separately acid alkylated with at least one isoparaffin. Expansion and liquid-vapor separation is utilized to separate the propylene from the butylenes. The use of expansion and separation improves the energy efficiency of the alkylation process. The energy efficiency of the alkylation process is further improved by utilizing the bottoms product from the acid stripper associated with the isostripper to cool the acid being supplied to the riser reactor. The size requirements of the isostripper are also reduced by using liquid-vapor separation to remove at least a portion of the unreacted isoparaffin from the alkylated butylenes.

Alkylation process

In the removal of HF from hydrocarbon streams by chemical reaction with solid potassium hydroxide, runaway temperatures and subsequent explosions can occur when excess HF is present in the hydrocarbon charged to the KOH treater. According to the invention, a control system and method are provided which regulate the flow of hydrocarbon charged to the KOH treater responsive to temperature changes within the system indicative of excessive amounts of HF in the hydrocarbon stream, thereby preventing the treater temperature from exceeding a preselected maximum allowable value. Several embodiments are provided whereby temperature changes in the KOH treater or a differential temperature across an HF stripper are used as temperature sensing points to control flow of hydrocarbon to the KOH treater.

Hydrocarbon purification apparatus

A process is provided for the alkylation of isoparaffins with olefins in the presence of an HF acid catalyst comprising separating a liquid hydrocarbon phase from the alkylation effluent, subjecting the hydrocarbon phase to HF stripping, separating the stripped hydrocarbon into a liquid and a vapor phase, fractionating the liquid phase into product streams, and pressurizing the vaporous stream prior to separation of C.sub.3 and lighter materials. The HF alkylation process utilizes indirect heat exchange of various streams and compression of HF-free vapors.

Alkylation separation process

A process is provided for the simultaneous and separate alkylation of an isoparaffin such as isobutane with different olefins, e.g., propylenes and butylenes in different zones with an HF acid catalyst comprising separating the hydrocarbon phase from each of the alkylation effluents, subjecting each hydrocarbon phase to separate HF stripping, fractionating the liquid phases removed from each of the HF stripping zones, pressurizing the vaporous isoparaffin stream recovered from fractionation and utilizing the pressurized vaporous streams for indirect heat exchange with HF strippers and fractionation zones prior to recycling through alkylation.

Parallel alkylation reactions utilizing pressured vaporous isoparaffin

In an acid catalyzed alkylation system, a prefractionated reactor hydrocarbon effluent bottoms stream, substantially free of HF, is passed to a propane concentrator in order to provide for a more concentrated and desirable feed for the depropanizer. Due to the highly concentrated propane stream fed to the depropanizer, the size of the depropanizer can be much smaller thereby saving in energy. Hot overhead vapor from the isostripper is also passed in an indirect heat exchange relationship with various feed streams and fractionators in order to supply heat for the preheating of the feed streams and the reboiling of the fractionators. The bottoms fraction of the isostripper can also be passed in an indirect heat exchange relationship with various feed streams and fractionators. The alkylation process, therefore, maximizes the use of available waste heat and reduces the pressure and utilities on the depropanizer thereby saving greatly on energy costs.

Energy efficient alkylation process

In the recovery of ethane and propane from an alkylation of an isoparaffin with an olefin to prevent buildup of ethane and propane in the system, the ethane and propane are taken as a side draw from the conventional HF stripper instead of being vented from the depropanizer or the fractionator overhead accumulator. Considerable ethane, propane and HF are thus saved and equipment costs reduced, especially because fractionator wall thickness can be reduced and because of the elimination of the equipment attendant the venting of the accumulator.

Alkylation effluent recovery system

An HF alkylation-fractionation system for the separation of the hydrocarbon phase separated from the HF alkylation effluent by passing the hydrocarbon phase first to a prefractionation zone operated at low pressure, followed by fractionation of both overhead and bottoms from the prefractionation zone at higher pressures and temperatures, and utilization of the high temperature streams obtained from the higher pressure fractionations as sources of heat for indirect heat exchange of the prefractionation zone and feed to at least one of the subsequent fractionations.

HF alkylation process utilizing fractionation zones at different

An olefin and isoparaffin are contacted in the presence of an acid alkylation catalyst to form an alkylate-containing alkylation effluent. The effluent is separated with the hydrocarbon phase passing to a prefractionation zone. A side stream from the prefractionation zone is passed in indirect heat exchange relationship with an interheater of an isostripper thereby providing a majority of the heat necessary to reboil the isostripper.

Alkylation process utilizing side draw vapor as heat source in

The bottom effluent from an isostripper of an HF alkylation system is combined with the bottom effluent consisting essentially of isopentanes and heavier hydrocarbons from a debutanizer column such as to produce an alkylate product stream under the provision that the mixing of the two streams is achieved in response to a signal representing the vapor pressure of the mixed streams.

In an HF alkylation of an isoparaffin, e.g., isobutane, with olefins, the hydrocarbon phase from the HF reactor effluent settler is charged to an HF separation zone. HF-free bottoms from the HF separation zone are charged to an isobutane stripper thereby producing HF-free isobutane vapor as overhead. The heat available in the isobutane vapor overhead is then utilized by compressing the vapor and using it as additional heat exchange fluid prior to being recycled to the HF alkylation. The compressed vapor can, for example, be used to reboil the HF separation zone, e.g., an HF stripper, heat the inner-heater on the isobutane stripper, and heat the depropanizer inner heater.

HF Alkylation process utilizing compressed isoparaffin vapor in indirect

In the removal of HF from hydrocarbon streams by chemical reaction with solid potassium hydroxide, runaway temperatures and subsequent explosions can occur when excess HF is present in the hydrocarbon charged to the KOH treater. According to the invention, a control system and method are provided which regulate the flow of hydrocarbon charged to the KOH treater responsive to temperature changes within the system indicative of excessive amount of HF in the hydrocarbon stream, thereby preventing the treater temperature from exceeding a preselected maximum allowable value. Several embodiments are provided whereby temperature changes in the KOH treater or a differential temperature across an HF stripper are used as temperature sensing points to control flow of hydrocarbon to the KOH treater.

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Bartlesville, OK, United States of America

Charles C Chapman