Phillips Petroleum Company

Bradley W DeLong

Michael L Gray

Jeffrey R Burkinshaw

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

By incorporating a gas permeable membrane into a hydrogen purification process at the front end of the cryogenic unit, the low purity hydrogen can be made into a high purity stream and a low purity stream. The critical pressure of the low purity stream is such that the low purity stream can be purified cryogenically without depressurization.

Gas separation

Normally gaseous feed materials, having a pressure significantly above ambient pressure, are cooled by passing the gaseous feed through an indirect heat exchange means, such as a plate-fin heat exchanger, passing a normally gaseous refrigerant, having a pressure substantially above ambient pressure, through the heat exchange means as a first stream in a concurrent direction with the feed stream, reducing the pressure of at least one second stream of refrigerant, preferably a plurality of second streams, as it exits the heat exchange means and passing the second stream of refrigerant, which has thus been reduced in pressure, through the heat exchange means in a countercurrent direction to the feed stream. This method can be employed for each cooling cycle of a method for cooling a natural gas stream to remove components therefrom and/or liquify the same.

Method for cooling normally gaseous material

A cryogenic hydrogen purification system is disclosed which produces low and high BTU substitute natural gas byproduct from a feed stream containing substantial carbon monoxide concentration. The required process cooling is provided by a pair of gas expanders. The purified hydrogen stream can be recycled to a hydroretort. The low BTU substitute natural gas stream contains most of the carbon monoxide. The high BTU natural gas stream forms suitable feed for a hydrogen plant.

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Bartlesville, OK, United States of America

Bradley W DeLong