Patent Application
20180306500
This invention relates generally to the field of cryogenic injection systems. More particularly, we are interested in preventing fouling of cryogenic injection systems by components of the gas.
Injection of gases into cryogenic fluids has unique difficulties over standard gas injection. Commercially available spray towers, bubble towers, distillation columns, and other equipment that utilizes gas injection are typically designed for removal of components of gas that do not desublimate or freeze out as solids. In other words, they do not experience desublimating fouling. However, with cryogenic systems, the gas injection systems, typically surrounded by cryogenic temperature liquids, often have components freezing out of the gas. For example, flue gas injected into a cryogenic liquid will have carbon dioxide and other acid gases, mercury, and other contaminants freeze out on the walls of the cryogenic injection system. This foulant quickly builds up and blocks the gas feed line. Further, the fluids used in these cryogenic systems, typically corrosive brines or strong organic solvents, are inimical to typical insulations, and so using insulation inside these systems is typically not considered an option. A system capable of handling these cryogenic temperatures for gas injection systems and preventing blockage of gas feed lines is required.
U.S. patent application Nos. 15/406,928 and 15/406,863 to Baxter, et al., teach methods and apparatuses for desublimation prevention in direct contact heat exchangers. The disclosure discloses a gas distribution apparatus for cryogenic gas injection into a cryogenic liquid. The present disclosure differs from this disclosure in that the system is not insulated. 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 preventing blockage of a cryogenic injection system is disclosed. The cryogenic injection system is provided comprising a gas feed line attached to a gas distributor. A gas is fed through the gas feed line and the gas distributor into a cryogenic liquid. A portion of the gas feed line passes through the cryogenic liquid. An insulative layer is provided for the portion of the gas feed line that passes through the cryogenic liquid. Heat transfer through the insulative layer between the portion of the gas feed line and the cryogenic liquid is countered sufficiently to prevent blockage of the gas feed line by a component or components of the gas. Blockage comprises fouling of an interior surface of the gas feed line sufficiently to prevent a desired flow rate of the gas through the gas feed line at a desired pressure; Fouling comprises the component or components condensing, desublimating, depositing, or a combination thereof onto the interior surface of the gas feed line. In this manner, blockage of the cryogenic injection system is prevented.
The countering step may be accomplished by sensible heat provided by the gas to the gas feed line, by heat from a heating element to the gas feed line, or a combination thereof.
The countering step may be accomplished in a manner preventing fouling of the interior surface. The gas distributor may comprise a bubbler, a sparger, a nozzle, or a combination thereof.
The cryogenic injection system may be deployed within a spray tower, bubble contactor, mechanically agitated tower, direct-contact heat exchanger, direct-contact material exchanger, or distillation column.
The gas may comprise flue gas, syngas, producer gas, natural gas, steam reforming gas, any hydrocarbon that has a lower freezing point than the temperature of the liquid, light gases, refinery off-gases, or combinations thereof.
The component or components may comprise carbon dioxide, nitrogen oxide, sulfur dioxide, nitrogen dioxide, sulfur trioxide, hydrogen sulfide, hydrogen cyanide, water, mercury, hydrocarbons with a freezing point above a temperature of the cryogenic liquid, or combinations thereof.
The cryogenic injection system may further comprise the gas feed line being sufficiently large that the component or components of the gas are allowed to build up on the interior surface of the gas feed line and become the insulative layer and prevent blockage of the cryogenic injection system.
The insulative layer may comprise vacuum jacketing, gas jacketing, pearlite, aerogel blankets, aerogel beads, polyimide foams, xeolites, polyisocyanurate rigid foam, polyisocyanurate cellular glass, fiberglass, PTFE-coated fiberglass, Kevlar thread, low density ceramics, layers with a narrow gap, multilayer insulation, or combinations thereof, wherein the multilayer insulation comprises radiation shields separated by spacers, the spacers comprise polyester, nylon, mylar, or combinations thereof, and the radiation shields comprise aluminum foil.
The insulative layer may comprise a permeable insulation that traps a thin layer of the cryogenic liquid against the gas feed line, warming the thin layer of the cryogenic liquid to act as the insulative layer, the permeable insulation comprising a closed-cell foam plastic comprising polyethylene, polypropylene, nylon, or combinations thereof.
The interior surface of the gas feed line may comprise a material that inhibits adsorption of gases, prevents deposition of solids, or a combination thereof.
In some embodiments, the portion of the gas feed line that passes through the cryogenic liquid may be minimized.
In some embodiments, changes of direction in the portion of the gas feed line that passes through the cryogenic liquid may be minimized.
The cryogenic liquid may comprise any compound or mixture of compounds with a freezing point above a temperature at which the component or components condense, desublimate, or a combination thereof, onto the surface of the gas feed line.
The cryogenic liquid 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, 4-methyl-1-hexene, 4-methyl-1-pentene, 4-methylcyclopentene, 4-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 cryogenic liquid may further comprise particulates, mercury, other heavy metals, condensed organics, soot, inorganic ash components, biomass, salts, frozen condensable gases, frozen absorbed gases, impurities common to vitiated flows, impurities common to producer gases, impurities common to other industrial flows, or combinations thereof.
The desired flow rate and the desired pressure may comprise a flow and a pressure capable of injecting the gas into the cryogenic liquid in a manner that allows for maximum heat, mass, or heat and mass transfer between the gas and the cryogenic liquid.
The gas distributor may comprise insulation.
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 countering step is accomplished by sensible heat provided by the gas to the gas feed line. In some embodiments, the countering step is accomplished by heat from a heating element to the gas feed line. In other embodiments, the countering step is accomplished by sensible heat provided by the gas and by heat from a heating element to the gas feed line. In some embodiments, the countering step is accomplished in a manner preventing fouling of the interior surface.
In some embodiments, the gas distributor comprises a bubbler, a sparger, a nozzle, or a combination thereof. In some embodiments, the cryogenic injection system is deployed within a spray tower, bubble contactor, mechanically agitated tower, direct-contact heat exchanger, direct-contact material exchanger, or distillation column.
In some embodiments, the gas comprises flue gas, syngas, producer gas, natural gas, steam reforming gas, any hydrocarbon that has a lower freezing point than the temperature of the liquid, light gases, refinery off-gases, or combinations thereof.
In some embodiments, the component or components comprise carbon dioxide, nitrogen oxide, sulfur dioxide, nitrogen dioxide, sulfur trioxide, hydrogen sulfide, hydrogen cyanide, water, mercury, hydrocarbons with a freezing point above a temperature of the cryogenic liquid, or combinations thereof.
In some embodiments, the cryogenic injection system further comprises the gas feed line being sufficiently large that the component or components of the gas are allowed to build up on the interior surface of the gas feed line and become the insulative layer and prevent blockage of the cryogenic injection system.
In some embodiments, the insulative layer comprises vacuum jacketing, gas jacketing, pearlite, aerogel blankets, aerogel beads, polyimide foams, xeolites, polyisocyanurate rigid foam, polyisocyanurate cellular glass, fiberglass, PTFE-coated fiberglass, Kevlar thread, low density ceramics, layers with a narrow gap, multilayer insulation, or combinations thereof, wherein the multilayer insulation comprises radiation shields separated by spacers, the spacers comprise polyester, nylon, mylar, or combinations thereof, and the radiation shields comprise aluminum foil.
In some embodiments, the insulative layer comprises a permeable insulation that traps a thin layer of the cryogenic liquid against the gas feed line, warming the thin layer of the cryogenic liquid to act as the insulative layer, the permeable insulation comprising a closed-cell foam plastic comprising polyethylene, polypropylene, nylon, or combinations thereof.
In some embodiments, the interior surface of the gas feed line comprises a material that inhibits adsorption of gases, prevents deposition of solids, or a combination thereof.
In some embodiments, the portion of the gas feed line that passes through the cryogenic liquid is minimized.
In some embodiments, changes of direction in the portion of the gas feed line that passes through the cryogenic liquid are minimized.
In some embodiments, the cryogenic liquid comprises any compound or mixture of compounds with a freezing point above a temperature at which the component or components condense, desublimate, or a combination thereof, onto the surface of the gas feed line.
In some embodiments, the cryogenic liquid 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, 4-methyl-1-hexene, 4-methyl-1-pentene, 4-methylcyclopentene, 4-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 cryogenic liquid further comprises particulates, mercury, other heavy metals, condensed organics, soot, inorganic ash components, biomass, salts, frozen condensable gases, frozen absorbed gases, impurities common to vitiated flows, impurities common to producer gases, impurities common to other industrial flows, or combinations thereof.
In some embodiments, the desired flow rate and the desired pressure comprise a flow and a pressure capable of injecting the gas into the cryogenic liquid in a manner that allows for maximum heat, mass, or heat and mass transfer between the gas and the cryogenic liquid.
In some embodiments, insulation is provided for the gas distributor.
Combustion flue gas consists of the exhaust gas from a fireplace, oven, furnace, boiler, steam generator, or other combustor. The combustion fuel sources include coal, hydrocarbons, and biomass. Combustion flue gas varies greatly in composition depending on the method of combustion and the source of fuel. Combustion in pure oxygen produces little to no nitrogen in the flue gas. Combustion using air leads to the majority of the flue gas consisting of nitrogen. The non-nitrogen flue gas consists of mostly carbon dioxide, water, and sometimes unconsumed oxygen. Small amounts of carbon monoxide, nitrogen oxides, sulfur dioxide, hydrogen sulfide, and trace amounts of hundreds of other chemicals are present, depending on the source. Entrained dust and soot will also be present in all combustion flue gas streams. The method disclosed applies to any combustion flue gases. Dried combustion flue gas has had the water removed.
Syngas consists of hydrogen, carbon monoxide, and carbon dioxide.
Producer gas consists of a fuel gas manufactured from materials such as coal, wood, or syngas. It consists mostly of carbon monoxide, with tars and carbon dioxide present as well.
Steam reforming is the process of producing hydrogen, carbon monoxide, and other compounds from hydrocarbon fuels, including natural gas. The steam reforming gas referred to herein consists primarily of carbon monoxide and hydrogen, with varying amounts of carbon dioxide and water.
Light gases include gases with higher volatility than water, including hydrogen, helium, carbon dioxide, nitrogen, and oxygen. This list is for example only and should not be implied to constitute a limitation as to the viability of other gases in the process. A person of skill in the art would be able to evaluate any gas as to whether it has higher volatility than water.
Refinery off-gases comprise gases produced by refining precious metals, such as gold and silver. These off-gases tend to contain significant amounts of mercury and other metals.
This invention was made with government support under DE-FE0028697 awarded by The Department of Energy. The government has certain rights in the invention.
