Abstract:
A semi-permeable membrane process of separating impurities from a hydrocarbon mixture. A fuel gas sweep gas is used to purge and dilute the permeate. Because this reduces the partial pressure of the impurities, the driving force for permeation is increased even though the permeate mixture pressure is increased to the extent that the system need not employ a compressor or vacuum pump. The mixture of permeate, fuel gas and permeated hydrocarbon product can be delivered at a pressure sufficient to flow directly to the plant fuel system or other system for use therein. Specific membrane units employing hollow fiber membranes or spirally wound stacked membrane layers are disclosed.
Abstract:
A transport process for a wet gas employs a subsea heat exchanger having first and second flowpaths separated by a heat transfer surface. A cooler heat transfer medium is conveyed through the first flowpath in a liquid phase while a warmer hydrocarbon stream having a gaseous hydrocarbon phase and a liquid aqueous phase is conveyed through the second flowpath, which cools the hydrocarbon stream and heats the heat transfer medium. The heat transfer medium is converted by heating to a vapor phase, which is conveyed to a passive condenser associated with the subsea heat exchanger. The ambient temperature of the sea water submersing the condenser cools the heat transfer medium and restores it to the liquid phase for reuse in the heat exchanger. A portion of the hydrocarbon stream is converted by cooling to a plurality of solid gas hydrate particles while a solid particle medium entrained within the hydrocarbon stream prevents the buil-up of gas hydrate particles in the second flowpath. The gas hydrate particles mix with the remaining liquid phase components of the hydrocarbon stream to form a gas hydrate slurry, which is withdrawn from the second flowpath and conveyed through a subsea transport pipeline.
Abstract:
A system and process are provided for converting a hydrocarbon gas to a reformed gas containing hydrogen and carbon monoxide. In accordance with a first embodiment, the system includes a primary combustor, compressor and power turbine. The process is practiced by compressing a feed air in the primary compressor to produce a primary air. The primary air is fed with a primary hydrocarbon gas to the primary combustor, producing a reformed gas that drives the primary power turbine. The primary power turbine is linked to the primary compressor, compressing the feed air in an energy self-sufficient manner. In a second embodiment, the system of the first embodiment further includes a secondary combustor, compressor and power turbine. The process is practiced in the same manner as the first embodiment, producing the reformed gas and driving the primary power turbine and compressor. A portion of the primary air is also fed with a secondary hydrocarbon gas to the secondary combustor, producing an off-gas that drives the secondary power turbine and compressor to compress a gas in an energy self-sufficient manner. In a third embodiment, the system is substantially the same as the second embodiment, but reconfigures the compressors and power turbines and further includes an auxiliary secondary power turbine. The process is practiced in the same manner as the first embodiment, producing the reformed gas and driving the primary power turbine and compressor. The off-gas is produced in the same manner as the second embodiment to drive the secondary power turbine, but the secondary power turbine drives an auxiliary primary compressor, compressing the feed air ahead of the primary compressor in an energy self-sufficient manner. The off-gas further drives the auxiliary secondary power turbine to provide additional power for alternate power users.
Abstract:
A process for converting gaseous alkanes to olefins and liquid hydrocarbons wherein a gaseous feed containing alkanes is reacted with a dry bromine vapor to form alkyl bromides and hydrobromic acid vapor. The mixture of alkyl bromides and hydrobromic acid are then reacted over a synthetic crystalline alumino-silicate catalyst, such as an X or Y type zeolite, at a temperature of from about 250° C. to about 500° C. so as to form olefins, higher molecular weight hydrocarbons and hydrobromic acid vapor. Various methods are disclosed to remove the hydrobromic acid vapor from the higher molecular weight hydrocarbons and to generate bromine from the hydrobromic acid for use in the process.
Abstract:
A process for converting gaseous alkanes to liquid hydrocarbons wherein a gaseous feed containing alkanes is reacted with a dry bromine vapor to form alkyl bromides and hydrobromic acid vapor. The mixture of alkyl bromides and hydrobromic acid are then reacted over a synthetic crystalline alumino-silicate catalyst, such as a ZSM-5 zeolite, at a temperature of from about 150° C. to about 450° C. so as to form higher molecular weight hydrocarbons and hydrobromic acid vapor. Propane and butane which comprise a portion of the products may be recovered or recycled back through the process to form additional C 5 + hydrocarbons. Various methods are disclosed to remove the hydrobromic acid vapor from the higher molecular weight hydrocarbons and to generate bromine from the hydrobromic acid for use in the process.
Abstract:
A system and process are provided for converting a light hydrocarbon gas to a synthetic heavier hydrocarbon liquid. The system includes an autothermal reformer, a Fischer-Tropsch reactor and a Brayton cycle that are structurally and functionally integrated. In the practice of the process, a mixture of a hydrocarbon feed gas, a compressed air feed and process steam is fed to the autothermal reformer to produce a synthesis gas. The synthesis gas is fed to the Fischer-Tropsch reactor where it is catalytically reacted to produce heavy hydrocarbons. The outlet from the Fischer-Tropsch reactor is separated into water, a low heating value tail gas, and the desired hydrocarbon liquid product. The water is pressurized and heated to generate process steam. The tail gas is heated and fed with compressed air and steam to the Brayton cycle having a combustor and a series of power turbines and compressors. The tail gas and air feed are burned in the combustor to produce a combustion gas that is used to drive a power turbine linked by a shaft to an air compressor, thereby driving the air compressor. The system further includes a plurality of heat exchangers that enable heat to be recovered from the outlet of the autothermal reformer. The recovered heat is used to make the process steam as well as to preheat the hydrocarbon feed gas before it is fed to the autothermal reformer, preheat the synthesis gas before it is fed to the Fischer-Tropsch reactor and preheat the tail gas before it is fed to the combustor.
Abstract:
A process for removing liquid sulfur from a reaction mixture during a gas treating process, especially a process for removing hydrogen sulfide from a gaseous stream. Sulfur which is formed during the process is removed from a reaction mixture by first concentrating the sulfur in a small portion of the reaction mixture and then heating this portion to a temperature which is sufficient to melt the sulfur. The molten sulfur is removed from the reaction mixture and washed with a suitable solvent to remove any remaining reaction mixture.
Abstract:
A process for removing hydrogen sulfide and other components, such as water, low molecular weight hydrocarbons, and carbon dioxide, which are contained in a gaseous feed stream and converting hydrogen sulfide to elemental sulfur and hydrogen. In accordance with the process, a gaseous feed stream containing hydrogen sulfide and other components is contacted with a polar organic solvent having a quinone and a complexing agent dissolved therein. The complexing agent must have a pKb value of less than about 13.0. Reaction of the hydrogen sulfide in the gaseous feed stream with quinone results in an increased conversion of quinone to hydroquinone at low reactor temperatures and H2S partial pressures and in increased sulfur recovery. In additon, the presence of a complexing agent increases hydrogen production selectivity in the dehydrogenation of hydroquinone to quinone and hydrogen. The polar organic solvent also functions to dissolve a significant portion of the other components from the gaseous feed stream which are separated and recovered as products.