Method for Preventing Fouling of Cryogenic Injection Systems

Abstract

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. In this manner, blockage of the cryogenic injection system is prevented.

Claims

1. A method for preventing blockage of a cryogenic injection system, comprising: providing the cryogenic injection system comprising a gas feed line attached to a gas distributor, wherein a gas is fed through the gas feed line and the gas distributor into a cryogenic liquid, and a portion of the gas feed line passes through the cryogenic liquid; and, providing an insulative layer for the portion of the gas feed line that passes through the cryogenic liquid, countering heat transfer through the insulative layer between the portion of the gas feed line and the cryogenic liquid sufficiently to prevent blockage of the gas feed line by a component or components of the gas, wherein 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, wherein fouling comprises the component or components condensing, desublimating, depositing, or a combination thereof onto the interior surface of the gas feed line; whereby blockage of the cryogenic injection system is prevented.

2. The method of claim 1, wherein the countering step is accomplished by sensible heat provided by the gas to the gas feed line

3. The method of claim 1, wherein the countering step is accomplished by heat from a heating element to the gas feed line.

4. The method of claim 1, wherein the countering step is accomplished by sensible heat provided by the gas and by heat from a heating element to the gas feed line.

5. The method of claim 1, wherein the countering step is accomplished in a manner preventing fouling of the interior surface.

6. The method of claim 1, providing the gas distributor comprising a bubbler, a sparger, a nozzle, or a combination thereof.

7. The method of claim 1, providing the cryogenic injection system deployed within a spray tower, bubble contactor, mechanically agitated tower, direct-contact heat exchanger, direct-contact material exchanger, or distillation column.

8. The method of claim 1, providing the gas comprising 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.

9. The method of claim 8, providing the component or components comprising 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.

10. The method of claim 9, providing the cryogenic injection system further comprising 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.

11. The method of claim 1, providing the insulative layer comprising 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.

12. The method of claim 1, providing the insulative layer comprising 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.

13. The method of claim 1, providing the interior surface of the gas feed line comprising a material that inhibits adsorption of gases, prevents deposition of solids, or a combination thereof.

14. The method of claim 1, minimizing the portion of the gas feed line that passes through the cryogenic liquid.

15. The method of claim 1, minimizing changes of direction in the portion of the gas feed line that passes through the cryogenic liquid.

16. The method of claim 1, providing the cryogenic liquid comprising 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.

17. The method of claim 16, providing the cryogenic liquid further comprising 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.

18. The method of claim 1, providing the cryogenic liquid further comprising 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.

19. The method of claim 1, providing the desired flow rate and the desired pressure comprising 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.

20. The method of claim 1, further comprising providing insulation for the gas distributor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] 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:

[0023] FIG. 1 shows Prior Art for bubbling a gas into a cryogenic liquid in a cryogenic injection system.

[0024] FIG. 2 shows a cross-section of a cryogenic injection system that prevents blockage.

[0025] FIG. 3 shows a cross-section of a bubble contactor that utilizes the cryogenic injection system of FIG. 2.

[0026] FIG. 4 shows a cross-section of a cryogenic injection system that prevents blockage.

[0027] FIG. 5 shows a cross-section of a bubble contactor that utilizes the cryogenic injection system of FIG. 4.

[0028] FIG. 6 shows a cross-section of a cryogenic injection system as part of a mechanically agitated bubble contactor that prevents blockage.

[0029] FIG. 7 shows a method for preventing blockage of a cryogenic injection system.

DETAILED DESCRIPTION

[0030] 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.

[0031] Referring to FIG. 1, Prior Art for bubbling a gas into a cryogenic liquid in a cryogenic injection system is shown at 100. Gas 110 is passed into gas feed line 106 and through gas distributor 104, bubbling into cryogenic liquid 114. Cryogenic liquid 114 passes downward across gas distributor 104 and gas feed line 106 and out of outlet 108, cooling gas 110 sufficient to cause a portion of a component or components of gas 110 to condense, desublimate, or deposit onto the interior surfaces of the gas feed line as foulant 116. Foulant 116 blocks gas feed line 106. Blockage comprises fouling of the interior surface of gas feed line 106 sufficient to prevent a desired flow rate of gas 110 through gas feed line 106 at a desired pressure. In some cases, this level of foulant requires complete closing of gas feed line 106. In other cases, any foulant 116 buildup comprises blockage, as the restriction to flow changes the desired flow rate or the desired pressure, or both. A method for preventing blockage is required.

[0032] Referring to FIG. 2, a cross-section of a cryogenic injection system that prevents blockage is shown at 200, as per one embodiment of the present invention. Cryogenic injection system 202 comprises gas feed line 206, insulative layer 216, and bubbler 204. Gas 210 is provided to gas feed line 206 and passed through bubbler 204, bubbling into cryogenic liquid 214. Cryogenic liquid 214 passes downward across bubbler 204, insulative layer 216, and leaves through outlet 208, cooling insulative layer 216. Heat transfer from cryogenic liquid 214 is countered by sensible heat from gas 210, preventing fouling and blockage of gas feed line 206. Fouling comprises condensation, desublimation, or deposition of a component or components of gas 210 onto an interior surface of gas feed line 206. Blockage comprises fouling of the interior surface of gas feed line 206 sufficient to prevent a desired flow rate of gas 210 through gas feed line 206 at a desired pressure.

[0033] Referring to FIG. 3, a cross-section of a bubble contactor that utilizes cryogenic injection system 202 of FIG. 2 is shown at 300. Bubble contactor 302 comprises liquid inlet 304, gas inlet 310, liquid outlet 306, gas outlet 308, demister 322, and cryogenic injection system 312. Cryogenic liquid 314 is provided to bubble contactor 302 through liquid inlet 304. Gas 318 is provided to cryogenic injection system 312 through gas inlet 310 and bubbles through cryogenic liquid 314. Cryogenic liquid 314 strips a component or components of gas 318, becoming component-rich cryogenic liquid 316, leaving through liquid outlet 306, while gas 318 becomes component-depleted gas 320, leaving through gas outlet 308. Cryogenic injection system 312 is insulated, as in FIG. 2, and prevents blockage of the gas feed line of cryogenic injection system 312.

[0034] Referring to FIG. 4, a cross-section of a cryogenic injection system that prevents blockage is shown at 400, as per one embodiment of the present invention. Cryogenic injection system 402 comprises gas feed line 406, insulative layer 416, and sparger 404. Gas 410 is provided to gas feed line 406 and passed through sparger 404, bubbling into cryogenic liquid 414. Cryogenic liquid 414 passes downward across sparger 404 and insulative layer 416, cooling insulative layer 416. Heat transfer from cryogenic liquid 414 is countered by sensible heat from gas 410, preventing fouling and blockage of gas feed line 406. Fouling comprises condensation, desublimation, or deposition of a component or components of gas 410 onto an interior surface of gas feed line 406. Blockage comprises fouling of the interior surface of gas feed line 406 sufficient to prevent a desired flow rate of gas 410 through gas feed line 406 at a desired pressure.

[0035] Referring to FIG. 5, a cross-section of a bubble contactor that utilizes cryogenic injection system 402 of FIG. 4 is shown at 500. Bubble contactor 502 comprises liquid inlet 504, gas inlet 510, liquid outlet 506, gas outlet 508, bubble tray 522, and cryogenic injection system 512. Cryogenic liquid 514 is provided to bubble contactor 502 through liquid inlet 504. Gas 518 is provided to cryogenic injection system 512 through gas inlet 510 and bubbles through cryogenic liquid 514. Cryogenic liquid 514 strips a component or components of gas 518, becoming component-rich cryogenic liquid 516, leaving through liquid outlet 506, while gas 518 becomes component-depleted gas 520, leaving through gas outlet 504. Cryogenic injection system 512 is insulated, as in FIG. 2, and prevents blockage of the gas feed line of cryogenic injection system 512.

[0036] Referring to FIG. 6, a cross-section of a cryogenic injection system as part of a mechanically agitated bubble contactor that prevents blockage is shown at 600, as per one embodiment of the present invention. Contactor 602 comprises cryogenic injection system 604, liquid inlet 606, gas outlet 616 and liquid outlet 608. Cryogenic injection system 604 comprises gas feed line 610, insulative layer 612, and agitator fins 614. Gas 620 is provided to gas feed line 610 and passed through insulative layer 612, bubbling into cryogenic liquid 622. Cryogenic liquid 622 is agitated by agitator fins 614, causing frothing of cryogenic liquid 622, resulting in gas 620 contacting cryogenic liquid 622 more effectively. Cryogenic liquid 622 strips a component or components of gas 620, becoming component-rich cryogenic liquid 622, while gas 620 becomes component-depleted gas 622. Component-rich cryogenic liquid 620 passes out of contactor 602 through liquid outlet 608 after cooling insulative layer 612. Component-depleted gas 622 passes out of gas outlet 616. Heat transfer from cryogenic liquid 622 is countered by sensible heat from gas 620, preventing fouling and blockage of gas feed line 610. Fouling comprises condensation, desublimation, or deposition of a component or components of gas 620 onto an interior surface of gas feed line 610. Blockage comprises fouling of the interior surface of gas feed line 610 sufficient to prevent a desired flow rate of gas 620 through gas feed line 610 at a desired pressure.

[0037] Referring to FIG. 7, a method for preventing blockage of a cryogenic injection system is shown at 700, as per one embodiment of the present invention. The cryogenic injection system is provided with a gas feed line attached to a gas distributor 101. 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 102. An insulative layer is provided for the portion of the gas feed line that passes through the cryogenic liquid 103. 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 104.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] In some embodiments, the portion of the gas feed line that passes through the cryogenic liquid is minimized.

[0047] In some embodiments, changes of direction in the portion of the gas feed line that passes through the cryogenic liquid are minimized.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] In some embodiments, insulation is provided for the gas distributor.

[0053] 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.

[0054] Syngas consists of hydrogen, carbon monoxide, and carbon dioxide.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.