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.

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.