Phillips Petroleum Company

Michael L Gray

Robert M Bellinger

Keith W Hovis

Henry K Hachmuth

Dwight L McKay

William A McClintock

Bradley W DeLong

Kristie C Gibson

A process and apparatus for recovering propane product from HF alkylation process that is substantially free of HF acid. The invention allows for the improvement in the operation of an HF alkylation propane stripper by utilizing a bottoms recycle stream.

Control of HF alkylation propane stripper

Isobutane and propane are separately charged to different catalytic dehydrogenation zones. The reaction products, including principally propylene and isobutylene, are combined, followed by separation of steam condensate, carbon dioxide and fuel gas from the mixture of effluents from the two separate dehydrogenation reaction zones. Propane and propylene are then separated from the isobutylene. The propylene product is recovered, and isobutylene is charged to an etherification reactor and there reacted with methanol to yield methyltertiarybutyl ether (MTBE). The etherification reactor effluent is fractionated to separate MTBE from n-butane and from isobutane. The latter is separated from n-butane and recycled to the isobutane dehydrogenation zone. Unreacted propane is also recovered and recycled.

Process for concurrently producing propylene and methyltertiarybutyl

A super-pressured, sub-cooled feed gas, predominating in methane and containing significant amounts of ethane and higher hydrocarbons and nitrogen, is separated by passing the feed gas through at least one separation step to separate a vapor phase and a liquid phase, fractionating the liquid phase to recover ethane and higher hydrocarbons as a liquid and a pipeline gas as a vapor phase product, the vapor phase from the separation step is then sequentially fractionated in second, third and fourth fractionation steps to produce liquid phase from the second fractionation step, which is recycled to the first fractionation step as a reflux, a liquid phase from the third fractionation step which is recovered as a product pipeline gas, a liquid phase from the fourth fractionation step which is recovered as an in-plant fuel and a vapor phase from the fourth fractionation step which is vented to the atmosphere as substantially pure nitrogen. The vapor phase from the first fractionation step and the liquid phases from the third and fourth fractionation step and the vapor from the fourth fractionation step are passed in indirect heat exchange with portions of the feed gas to cool the same and portions of the vapor phase from the separation step, the second fractionation step and the third fractionation step are utilized in reboilers to heat the second, third and fourth fractionation steps.

Recovery of NGL's and rejection of N.sub.2 from natural gas

Overloading of a plurality of turbine drivers driving compressors in a plurality of compression cycles, such as the compression of refrigerants and the compression of normally gaseous feed in a method for cryogenically cooling such normally gaseous feed, due to changes in compressor limiting operating conditions, is prevented by measuring the suction pressures to the low pressure stages of the compressors, deriving a desired feed flow rate in response to each of such measured suction pressures, selecting the lowest desired feed flow rate (which will be derived in response to the highest measured suction pressure if all set points are equal), and adjusting the feed gas flow rate in response to the lowest flow rate. In a preferred embodiment, a manual set point representing a maximum feed gas flow rate is also applied and the selected feed rate is dictated by the highest suction pressure or the maximum feed rate, whichever is lower, and is utilized to adjust the feed rate. In another embodiment, the speeds of the individual turbine drivers are controlled in response to the low stage suction pressures to each of the individual turbine drivers.

Feed control for cryogenic gas plant

A process and apparatus for reducing the nitrogen content of a liquefied, normally gaseous feed comprising predominantly methane with a significant amount of nitrogen and having an elevated pressure in which the feed is separated into a first vapor phase portion, containing a major portion of nitrogen, and an unvaporized first liquid phase portion, the first vapor phase portion is cooled, the cooled first vapor phase portion is further separated into a second vapor phase portion, further enriched in nitrogen, and an unvaporized second liquid phase portion, the unvaporized first and second liquid phase portions are combined, an expanded body of fluids is formed from the combined unvaporized first and second liquid phase portions, at least part of the cooling of the first vapor phase portion is carried out by passing the same in indirect heat exchange with the expanded body of fluids formed from the unvaporized first and second liquid phase portions and the expanded body of fluids formed from the unvaporized first and second liquid phase portions is separated into a third vapor phase portion and an unvaporized third liquid phase portion.

Separation of nitrogen from natural gas

In accordance with the present invention a natural gas stream predominating in methane and containing significant amounts of C.sub.2, C.sub.3, C.sub.4 and C.sub.5 and higher molecular weight hydrocarbons is cooled in a plurality of cooling stages to a temperature sufficient to produce at least one liquid phase portion predominating in C.sub.2, C.sub.3, C.sub.4 and C.sub.5 and higher molecular weight hydrocarbons, the at least one liquid phase portion predominating in C.sub.2, C.sub.3, C.sub.4 and C.sub.5 and higher molecular weight hydrocarbons is separated from the main gas stream during the course of the cooling, the thus separated liquid phase portion or portions predominating in C.sub.2, C.sub.3, C.sub.4 and C.sub.5 and higher molecular weight hydrocarbons is further separated into a vapor phase portion predominating in C.sub.2, C.sub.3, and C.sub.4 hydrocarbons and at least one liquid phase portion predominating in C.sub.5 and higher molecular weight hydrocarbons, at least one second separation step, at least one portion of the at least one vapor phase portion predominating in C.sub.2, C.sub.3 and C.sub.4, hydrocarbons is recovered as at least one product of the process and at least one portion of the remaining portion of the at least one phase portion predominating in C.sub.2, C.sub.3 and C.sub.4 hydrocarbons is recycled to and recombined with the main gas stream as a liquid phase.

Cryogenic recovery of LPG from natural gas

In accordance with the present invention a normally gaseous feed mixture, having a temperature of essentially atmospheric temperature and a pressure substantially above atmospheric pressure, is cooled to a lower temperature sufficient to liquefy a portion of the feed mixture, the cooled feed mixture is separated into a first vapor phase and a first liquid phase, the first vapor phase is further cooled to a temperature sufficiently low to liquefy a portion of the first vapor phase, the cooled first vapor phase is separated into a second vapor phase and a second liquid phase, the pressures of the first liquid phase and the second liquid phase are separately reduced to a pressure sufficiently low to flash portions of the liquid phases, the reduced-pressure, first liquid phase is introduced into the lower portion of a third separation step while the reduced-pressure, second liquid phase is introduced into the upper portion of the third separation step, in which the reduced-pressure, first and second liquid phases are simultaneously separated to produce a third vapor phase and a third liquid phase, at least a portion of the second vapor phase is expanded to a pressure approximately the same as the reduced pressures of the first and second liquid phases but sufficiently low to liquefy a portion of the second vapor phase, the expanded second vapor phase, the remaining portion of the second vapor phase, if any, and the third vapor phase are introduced into the upper portion of a fourth separation step and the third liquid phase is introduced into the fourth separation step at a point below the previously mentioned upper portion of the fourth separation step and the streams introduced into the fourth separation step are simultaneously separated to produce a fourth liquid product enriched in higher boiling components and a fourth vapor product enriched in lower boiling components.

Natural gas processing

In the separation of low boiling gases such as ethane or propane and heavier from a gas stream such as natural gas, a first portion of the feed is heat exchanged with an overhead from a downstream stripper column, such as a demethanizer, a second portion is heat exchanged with a stream from a lower portion of said stripper column, and these two portions passed as separate streams to a separator-contactor. The first stream is added at a point above the second. This results in an increase in the recovery of liquid products.

Separate feed entry to separator-contactor in gas separation

In the separation of low boiling gases such as ethane and heavier from natural gas utilizing two expanders in series, liquid condensed before expansion is not passed to the fractionator but is flashed and the resulting vapor combined with the expanded vapor from the first expander. This results in both increased work output from the second expander and simplified design of the downstream fractionator column since it reduces the amount of lighter materials introduced into the lower section thereof.

Growing community of inventors

Bartlesville, OK, United States of America

Michael L Gray