Patent Application
20180306496
This invention relates generally to the field of separations. More particularly, we are interested in separating acid gases, such as carbon dioxide, from cryogenic liquids.
The art of separations is well developed for the majority of standard applications. However, cryogenic separations are still a relatively new field and many difficult separation problems still exist. One of these is separating carbon dioxide and other acid gases from various carrier gases. Scrubbing of these carrier gases by various organic solvents produces slurries that can be compressed to further produce liquid mixtures of carbon dioxide and the solvents. However, separating these solvents from the carbon dioxide at high purity is energy intensive and cost prohibitive. The ability to effectively separate liquid carbon dioxide and other liquefied acid gases from carrier solvents is required.
Venting of gases produced from liquid mixtures is used in every industry where a gas or vapor may volatilize and thereby over-pressurize a vessel, pipe, or other equipment. However, using this tendency to purposefully make a purified product gas stream from a multi-component liquid mixture is not found. Because these gases and vapors are volatized from the liquid mixture as a byproduct and not under carefully tailored conditions, the vapors contain at least a portion of non-product components. The ability to produce vent gases and vapors with essentially no non-product components is required.
United States patent publication number 5974829, to Novak, et al., teaches a method for carbon dioxide recovery from a feed stream. At one point, the compressed flow is passed through a distillation column and separated into a vent gas containing some carbon dioxide and a high purity bottom liquid carbon dioxide stream. The present disclosure differs from this disclosure in that the vent gas is a mixture, not a pure carbon dioxide stream. This disclosure is pertinent and may benefit from the methods disclosed herein and is hereby incorporated for reference in its entirety for all that it teaches.
A method for producing a purified product stream is disclosed. A process stream is provided to a screw compressor, the process stream comprising a contact liquid stream and a product stream, wherein the product stream comprises a solid portion. The process stream is passed through the screw compressor and into a melting device. The solid portion of the product stream is melted in the melting device to a temperature and a pressure such that a portion of the product stream vaporizes, forming a purified product stream, and vaporization of the contact liquid stream into the purified product stream is essentially prevented. A restricted outlet is provided to an upper portion of the vessel. The restricted outlet is proportionally controlled such that the pressure and the temperature is maintained as the purified product stream passes through the restricted outlet. In this manner, the purified product stream is produced.
The product stream may comprise carbon dioxide, nitrogen oxide, sulfur dioxide, nitrogen dioxide, sulfur trioxide, hydrogen sulfide, hydrogen cyanide, water, condensed hydrocarbons, or combinations thereof.
The screw compressor may comprise a connection to the melting device above a level of the process stream. The screw compressor may comprise a connection to the melting device below a level of the process stream.
The restricted outlet may comprise a valve, a compressor, a pump, or a combination thereof. The vessel further may comprise a pressure sensor, an output of the pressure sensor transmitting the pressure. The proportionally controlling step may be accomplished by opening or closing the restricted outlet proportional to the pressure. The vessel may comprise a level sensor, an output of the level sensor transmitting a liquid level. The liquid level of the process stream in the melting device may be maintained by the output of the level sensor.
A controller may be provided, the controller receiving the output of the pressure sensor and the output of the level sensor and controlling the restricted outlet and the liquid level.
The melting device may comprise a shell and tube style heat exchanger, plate style heat exchanger, plate and frame style heat exchanger, plate and shell style heat exchanger, spiral style heat exchanger, plate fin style heat exchanger, or combinations thereof.
The contact liquid stream may comprise any compound or mixture of compounds with a freezing point below the temperature at which the product stream solidifies. The contact liquid stream may comprise water, brine, hydrocarbons, liquid ammonia, liquid carbon dioxide, other cryogenic liquids, other hydrocarbons, and combinations thereof. The contact liquid stream may comprise 1,1,3-trimethylcyclopentane, 1,4-pentadiene, 1,5-hexadiene, 1-butene, 1-methyl-1-ethylcyclopentane, 1-pentene, 3,3,3,3-tetrafluoropropene, 3,3-dimethyl-1-butene, 3-chloro-1,1,1,2-tetrafluoroethane, 3-methylpentane, 3-methyl-1,4-pentadiene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-methylpentane, 5-methyl-1-hexene, 5-methyl-1-pentene, 5-methylcyclopentene, 5-methyl-trans-2-pentene, bromochlorodifluoromethane, bromodifluoromethane, bromotrifluoroethylene, chlorotrifluoroethylene, cis 3-hexene, cis-1,3-pentadiene, cis-2-hexene, cis-2-pentene, dichlorodifluoromethane, difluoromethyl ether, trifluoromethyl ether, dimethyl ether, ethyl fluoride, ethyl mercaptan, hexafluoropropylene, isobutane, isobutene, isobutyl mercaptan, isopentane, isoprene, methyl isopropyl ether, methylcyclohexane, methylcyclopentane, methylcyclopropane, n,n-diethylmethylamine, octafluoropropane, pentafluoroethyl trifluorovinyl ether, propane, sec-butyl mercaptan, trans-2-pentene, trifluoromethyl trifluorovinyl ether, vinyl chloride, bromotrifluoromethane, chlorodifluoromethane, dimethyl silane, ketene, methyl silane, perchloryl fluoride, propylene, vinyl fluoride, or combinations thereof.
The process stream may comprise a solid portion comprising particulates, mercury, other heavy metals, condensed organics, soot, inorganic ash components, biomass, salts, water ice, frozen acid gases, other impurities common to a vitiated flow, the producer gases, or the other industrial flows, or combinations thereof.
The purified product stream may be provided to a pure liquid product stream to condense the purified product stream into the pure liquid product stream. The purified product stream may be cooled in a heat exchanger, producing a cooled purified product stream. The cooled purified product stream may be compressed into a liquid phase, producing a liquefied pure product stream. The liquefied pure product stream may be passed through a heat exchanger.
The screw compressor may comprise porous walls through which a portion of the contact liquid stream is removed.
In order that the advantages of the invention will be readily understood, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered limiting of its scope, the invention will be described and explained with additional specificity and detail through use of the accompanying drawings, in which:
It will be readily understood that the components of the present invention, as generally described and illustrated in the Figures herein, could be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description of the embodiments of the invention, as represented in the Figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of certain examples of presently contemplated embodiments in accordance with the invention.
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In some embodiments, the product stream further comprising carbon dioxide, nitrogen oxide, sulfur dioxide, nitrogen dioxide, sulfur trioxide, hydrogen sulfide, hydrogen cyanide, water, condensed hydrocarbons, or combinations thereof.
In some embodiments, the screw compressor comprises a connection to the melting device above a level of the process stream. In other embodiments, the screw compressor comprises a connection to the melting device below a level of the process stream.
In some embodiments, the restricted outlet comprises a valve, a compressor, a pump, or a combination thereof. In some embodiments, the vessel further comprises a pressure sensor, an output of the pressure sensor transmitting the pressure. In some embodiments, the proportionally controlling step is accomplished by opening or closing the restricted outlet proportional to the pressure. In some embodiments, the vessel further comprises a level sensor, an output of the level sensor transmitting a liquid level. In some embodiments, the liquid level of the process stream in the melting device is maintained by the output of the level sensor. In some embodiments, a controller is provided, the controller receiving the output of the pressure sensor and the output of the level sensor and controlling the restricted outlet and the liquid level.
In some embodiments, the melting device comprises a shell and tube style heat exchanger, plate style heat exchanger, plate and frame style heat exchanger, plate and shell style heat exchanger, spiral style heat exchanger, plate fin style heat exchanger, or combinations thereof.
In some embodiments, the contact liquid stream comprises any compound or mixture of compounds with a freezing point below the temperature at which the product stream solidifies. In some embodiments, the contact liquid stream comprises water, brine, hydrocarbons, liquid ammonia, liquid carbon dioxide, other cryogenic liquids, other hydrocarbons, and combinations thereof. In some embodiments, the contact liquid stream comprises 1,1,3-trimethylcyclopentane, 1,4-pentadiene, 1,5-hexadiene, 1-butene, 1-methyl-1-ethylcyclopentane, 1-pentene, 3,3,3,3-tetrafluoropropene, 3,3-dimethyl-1-butene, 3-chloro-1,1,1,2-tetrafluoroethane, 3-methylpentane, 3-methyl-1,4-pentadiene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-methylpentane, 5-methyl-1-hexene, 5-methyl-1-pentene, 5-methylcyclopentene, 5-methyl-trans-2-pentene, bromochlorodifluoromethane, bromodifluoromethane, bromotrifluoroethylene, chlorotrifluoroethylene, cis 3-hexene, cis-1,3-pentadiene, cis-2-hexene, cis-2-pentene, dichlorodifluoromethane, difluoromethyl ether, trifluoromethyl ether, dimethyl ether, ethyl fluoride, ethyl mercaptan, hexafluoropropylene, isobutane, isobutene, isobutyl mercaptan, isopentane, isoprene, methyl isopropyl ether, methylcyclohexane, methylcyclopentane, methylcyclopropane, n,n-diethylmethylamine, octafluoropropane, pentafluoroethyl trifluorovinyl ether, propane, sec-butyl mercaptan, trans-2-pentene, trifluoromethyl trifluorovinyl ether, vinyl chloride, bromotrifluoromethane, chlorodifluoromethane, dimethyl silane, ketene, methyl silane, perchloryl fluoride, propylene, vinyl fluoride, or combinations thereof.
In some embodiments, the process stream comprises a solid portion comprising particulates, mercury, other heavy metals, condensed organics, soot, inorganic ash components, biomass, salts, water ice, frozen acid gases, other impurities common to a vitiated flow, the producer gases, or the other industrial flows, or combinations thereof.
In some embodiments, the purified product stream is provided to a pure liquid product stream to condense the purified product stream into the pure liquid product stream. In some embodiments, the purified product stream is cooled in a heat exchanger, producing a cooled purified product stream. In some embodiments, the cooled purified product stream is compressed into a liquid phase, producing a liquefied pure product stream. In some embodiments, the liquefied pure product stream is passed through a heat exchanger.
In some embodiments, the screw compressor further comprises porous walls through which a portion of the contact liquid stream is removed.
This invention was made with government support under DE-FE0028697 awarded by The Department of Energy. The government has certain rights in the invention.
