WO2015017357A1 - Procédé destiné à la liquéfaction de gaz naturel - Google Patents

Procédé destiné à la liquéfaction de gaz naturel Download PDF

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Publication number
WO2015017357A1
WO2015017357A1 PCT/US2014/048522 US2014048522W WO2015017357A1 WO 2015017357 A1 WO2015017357 A1 WO 2015017357A1 US 2014048522 W US2014048522 W US 2014048522W WO 2015017357 A1 WO2015017357 A1 WO 2015017357A1
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stream
natural gas
cooled
liquid
liquefied
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PCT/US2014/048522
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English (en)
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John L. GRIFFITHS
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Uop Llc
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Priority to CA2919209A priority Critical patent/CA2919209A1/fr
Publication of WO2015017357A1 publication Critical patent/WO2015017357A1/fr

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
    • F25J1/0002—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the fluid to be liquefied
    • F25J1/0022—Hydrocarbons, e.g. natural gas
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
    • F25J1/003—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production
    • F25J1/0032—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production using the feed stream itself or separated fractions from it, i.e. "internal refrigeration"
    • F25J1/0045—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production using the feed stream itself or separated fractions from it, i.e. "internal refrigeration" by vaporising a liquid return stream
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
    • F25J1/006—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the refrigerant fluid used
    • F25J1/007—Primary atmospheric gases, mixtures thereof
    • F25J1/0072—Nitrogen
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
    • F25J1/02—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process
    • F25J1/0203—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process using a single-component refrigerant [SCR] fluid in a closed vapor compression cycle
    • F25J1/0204—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process using a single-component refrigerant [SCR] fluid in a closed vapor compression cycle as a single flow SCR cycle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/0204—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the feed stream
    • F25J3/0209—Natural gas or substitute natural gas
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/0228—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream
    • F25J3/0233—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream separation of CnHm with 1 carbon atom or more
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/0228—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream
    • F25J3/0238—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream separation of CnHm with 2 carbon atoms or more
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/0228—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream
    • F25J3/0257—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream separation of nitrogen
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
    • C10L3/00—Gaseous fuels; Natural gas; Synthetic natural gas obtained by processes not covered by subclass C10G, C10K; Liquefied petroleum gas
    • C10L3/06—Natural gas; Synthetic natural gas obtained by processes not covered by C10G, C10K3/02 or C10K3/04
    • C10L3/10—Working-up natural gas or synthetic natural gas
    • C10L3/101—Removal of contaminants
    • C10L3/106—Removal of contaminants of water
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2205/00—Processes or apparatus using other separation and/or other processing means
    • F25J2205/30—Processes or apparatus using other separation and/or other processing means using a washing, e.g. "scrubbing" or bubble column for purification purposes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2205/00—Processes or apparatus using other separation and/or other processing means
    • F25J2205/84—Processes or apparatus using other separation and/or other processing means using filter
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2215/00—Processes characterised by the type or other details of the product stream
    • F25J2215/04—Recovery of liquid products
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2220/00—Processes or apparatus involving steps for the removal of impurities
    • F25J2220/60—Separating impurities from natural gas, e.g. mercury, cyclic hydrocarbons
    • F25J2220/62—Separating low boiling components, e.g. He, H2, N2, Air
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2220/00—Processes or apparatus involving steps for the removal of impurities
    • F25J2220/60—Separating impurities from natural gas, e.g. mercury, cyclic hydrocarbons
    • F25J2220/64—Separating heavy hydrocarbons, e.g. NGL, LPG, C4+ hydrocarbons or heavy condensates in general
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2220/00—Processes or apparatus involving steps for the removal of impurities
    • F25J2220/60—Separating impurities from natural gas, e.g. mercury, cyclic hydrocarbons
    • F25J2220/66—Separating acid gases, e.g. CO2, SO2, H2S or RSH
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2220/00—Processes or apparatus involving steps for the removal of impurities
    • F25J2220/60—Separating impurities from natural gas, e.g. mercury, cyclic hydrocarbons
    • F25J2220/68—Separating water or hydrates
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2270/00—Refrigeration techniques used
    • F25J2270/42—Quasi-closed internal or closed external nitrogen refrigeration cycle

Definitions

  • Liquefied natural gas or LNG is natural gas (predominantly methane, CH4) that has been converted to liquid form for ease of storage or transport.
  • the liquefaction process involves removal of certain components, such as dust, acid gases, helium, water, and heavy hydrocarbons, which could cause difficulty downstream in the liquefaction process.
  • the natural gas is condensed into a liquid at ambient pressure. It is typically liquefied at ambient pressure at -101°C (maximum transport pressure set at around 25 kPa (3.6 psi) and then cooled to -162°C by using a Joule-Thompson expansion or through the use of a subcooler. By raising the pressure of liquefaction, the latent duty is reduced, improving the efficiency of the liquefaction cycle. LNG achieves a higher reduction in volume
  • CNG compressed natural gas
  • cryogenic sea vessels or cryogenic road tankers are used for its transport.
  • the natural gas fed into the LNG plant is treated to remove water, hydrogen sulfide, carbon dioxide and other components that will freeze (such as benzene) under the low temperatures needed for storage or be destructive to the liquefaction facility.
  • hydrocarbons heavier than methane are removed for higher value uses.
  • LNG typically contains more than 90% methane. It also contains small amounts
  • the purification process can be designed to give almost 100% methane.
  • Pipeline natural gas typically contains levels of H 2 0, C0 2 , and other materials which are perceived to require removal prior to liquefaction. Due to their freeze points, during the cooling process, these materials will tend to foul the heat exchangers and lead to blockages. Therefore, in order to solve this problem, the industry will typically use PSA, solvent scrubbers and membranes in order to remove these contaminants prior to liquefaction. While cost effective in large scale units, the additional costs in small scale units tends to drive up the total cost of ownership for the production of LNG. The issue therefore is to extract these contaminants without adding large amounts of capital cost.
  • the invention provides a process and a system for producing a LNG product.
  • the process which uses several purification devices, chillers and a column, includes multiple steps.
  • At least a portion of the supply of natural gas is at least partially purified with removal of water and other contaminants.
  • the next step is to feed a stream of LNG as well as the supply of natural gas to a column such as a quench tower.
  • the first section of the process uses latent heat in the LNG to cool the feed incoming natural gas.
  • the first section is run with excess liquid such that the volatile components in the natural gas as condensed and frozen into the cooling liquid.
  • the chilled gas may be a quantity of the product from the process, liquefied natural gas. A portion of at least one contaminant condenses, solidifies or dissolves. The next step may be to filter out these contaminants followed by further cooling to the necessary temperature to produce LNG. In another embodiment of the invention, solids may end up in the end product.
  • the process involves liquefaction of natural gas, comprising cooling a natural gas stream to a temperature from 0° to -100°C to produce a cooled natural gas stream, sending the cooled natural gas stream to a quench unit, sending a quantity of liquefied natural gas to the quench unit to be combined with the cooled natural gas steam to produce a bottoms stream comprising an intermediate cooled natural gas stream comprising solid impurities and a top stream comprising methane and incondensable impurities, The bottoms stream is then sent to a unit to remove solid impurities to a produce a purified bottoms stream; and the purified bottoms stream is then cooled to produce liquefied natural gas.
  • the natural gas stream Prior to the cooling of the natural gas stream, at least a portion of water is removed as well as other contaminants.
  • the natural gas stream may be cooled to a temperature of -25° to ⁇ 75°C or -55° to _ 60°C.
  • the solid impurities that are removed include carbon dioxide, C 5 and C 6 hydrocarbons and water.
  • the incondensable impurities are selected from the group consisting of nitrogen, helium, oxygen and hydrogen.
  • the bottoms stream is at a temperature from -75° to -120°C and preferably it is at a temperature from -90° to - 100°C.
  • the invention also comprises a system for producing liquefied natural gas from a supply of natural gas, comprising a device for supplying a stream of natural gas, a separation device to remove water and other impurities from the stream of natural gas to produce a partially dried stream of natural gas, a means for feeding the partially dried stream of natural gas to a chilling device and then to a quench tower, a means for feeding a quantity of a chilled liquid to the quench tower where the chilled liquid and said partially dried stream of natural gas are present in said quench tower and a means to vent a purge stream from said quench tower; a means to transport a combination of the chilled liquid and the partially dried stream of natural gas to a filter unit; a means to transport a purified stream from the filter unit to a chiller to produce liquefied natural gas and a means to the said liquefied natural gas to a storage device.
  • the LNG may then be transported by ship or truck to a customer.
  • the invention overcomes the issue of fouling or blocking of the heat exchange device used to liquefy the natural gas by undertaking the majority of the cooling duty of the natural gas stream through direct contact with sub cooled LNG or saturated LNG.
  • the natural gas stream is introduced to a quench unit and sending a quantity of liquefied natural gas to the quench unit to be combined with the natural gas stream, a bottoms stream comprising solid impurities in a liquefied hydrocarbon is produced and a top stream comprising methane and incondensable impurities.
  • the bottoms stream is then sent to a unit to remove solid impurities to a produce a purified bottoms stream.
  • the bottoms stream may be cooled to the liquefied natural gas temperature prior to or after purification.
  • this cooling of the natural gas will produce a sub cooled liquefied natural gas.
  • a portion of the impurities, such as water, may be removed by first passing the gas through other impurity removal devices in order to enable some of the cooling to be undertaken in an indirect heat exchange device.
  • the natural gas stream may be cooled to a temperature of -25° to -75 °C prior to introduction into the quench device.
  • the solid impurities that are removed include carbon dioxide, C 5 and C 6 hydrocarbons and water.
  • the incondensable impurities are selected from the group consisting of nitrogen, oxygen, helium and hydrogen.
  • the bottoms stream is at a temperature from -75° to - 120°C and preferably it is at a temperature from -90° to -100°C.
  • the top stream may be condensed using either an indirect liquefaction process, such as a heat exchanger, or through direct contact with a portion of the sub cooled liquefied natural gas. Further, by running this top stream liquefied with excess sub cooled natural gas, a feed stream of sub cooled or saturated LNG may be provided to the quench unit.
  • FIG. 1 illustrates a flow scheme for the production of liquefied natural gas from natural gas through indirect condensation
  • FIG. 2 illustrates an alternative flow scheme of the production of liquefied natural gas from natural gas through direct condensation
  • FIG. 3 illustrates a flow scheme in which LNG is generated from the quench condensate
  • the invention solves the problem by undertaking the liquefaction in a way which does not lead to blockage of the condenser. Therefore, contaminants can be introduced into this unit, and then removed as a solid from the resulting LNG. While it is feasible to purify the natural gas to a level that allows for production of LNG, the present invention provides a process to reduce overall costs of production.
  • Low cost precleaning of the natural gas stream may also take place as needed, reducing the load on the filters.
  • the design would spray supercooled LNG into the top of a column, and introduce the warmer natural gas feed into the bottom where the supercooled LNG and warmer natural gas feed would mix. While the two fluids would be thermally in equilibrium at the top of the column, at the bottom there may be more than a 38°C (100°F) temperature difference in temperature between the liquid and the gas. The thermal equilibrium will occur partway down the column. Given that at the top of the column, liquefaction of the methane rich gas is taking place through contact with a methane rich liquid, the liquid must be at a colder temperature than the gas phase.
  • This quenching operation at the bottom of the column preferentially extracts the contaminants into the liquid phase where they can be extracted.
  • the lighter components rise up the column, where they in turn condense.
  • Some of the nitrogen, helium, hydrogen, argon and oxygen may exit the top of the column as a small purge stream while some of these gases may form part of the product.
  • a small portion of the methane stream will also escape into the purge stream.
  • All other components, including carbon dioxide and water, are condensed into a 'dirty' LNG then passes through a series of filters to be cleaned and then cooled to the necessary storage tank temperature of - 161 °C ( ⁇ 257°F) by using Joule -Thompson expansion or a subcooler.
  • the unit therefore would consist of a low cost front end bed (dryer or similar unit), precooler, wash column, filter, subcooler, storage tank and pump.
  • US 6,637,240 described a method for making nitrogen gas using a tank of liquid nitrogen. Cool air is introduced into the bottom, and liquid nitrogen is introduced at the top. Akin to this unit, the temperature difference at the bottom of the column produces the same sort of cryogenic quench. Further the bottoms (a crude dirty liquid oxygen) is viewed as waste and not subsequently subcooled in order to generate both a product as well as the quenching liquid. In other cryogenic nitrogen patents, the crude liquid oxygen is sub cooled through a Joule Thompson effect and used to provide liquid to the top of the column.
  • FIG. 3 shows a simplified flow sheet of the process of the present invention.
  • a purge stream containing the incondensable contaminants exits from the top of the column as well as a portion of the methane.
  • a bottom stream at -100°C contains all of the impurities left by the feed scrubber. Due to the cold temperature, these are in the solid form.
  • a simple mesh filter would then be used to remove these particles, and the liquid would then be further chilled to - 161°C ( ⁇ 257°F) for storage.
  • subcooled LNG would be extracted from the storage tank and used in the quench chiller. Simulations suggested that a simple closed nitrogen refrigeration cycle would provide sufficient cooling for this process using 309 hp of power in order to condense 9071 kg (10 tons)/day of LNG. Rather than requiring steam, solvents and other front end purification processes, this unit would run using higher power, a quench tower and a simple filtration device.
  • FIG. 1 presents one embodiment of the invention which does not generate LNG though direct condensation, nor does it use the bottoms liquid as a source of the product.
  • a natural gas stream 2 is introduced into a simple PSA 6 wherein a portion of the water is removed producing a dry natural gas stream 8 with a dew point below ⁇ 50°C and a purge stream 10 containing the removed moisture.
  • Stream 8 is then cooled to _ 50°C in an indirect heat exchanger 12 to produce a chilled dry natural gas stream 14.
  • Stream 14 is then introduced into the quench column 16 wherein it is cooled to -100°C through direct contact with a primary cooling liquid and a substantial portion of the heavy components within stream 14 condense and solidify into the dirty heavy bottom liquid 18.
  • a portion of the primary cooling liquid is evaporated during this process and mixes with the light components of stream 14 and exits the quench column 16 as the chilled medium gas 20.
  • Stream 20 is then further cooled through direct contact in a secondary cooler 22 with a secondary cooling liquid, removing further impurities such as C 2 and C 3 to producing a medium bottom liquid 24 which is fed to the quench column 16 to provide a portion of the primary cooling liquid.
  • the solids in stream 18 are removed through the use of a filter 28 producing a heavy liquid 30 and a solid waste stream 32.
  • Stream 30 is then raised in pressure in recycle pump 34 and fed as heavy cooling liquid 36 to quench column 16 where it forms part of the primary cooling fluid.
  • the remaining uncondensed portion of stream 20 exits the secondary cooler 22 as a light chilled gas 26 and is fully condensed in a liquefier 38 and fed as a light liquid stream 40 to a storage tank 42.
  • a draw stream 44 is removed from tank 42, reduced in pressure by regulator 46 and delivered as liquefied natural gas 48.
  • a light liquid draw stream 50 is withdrawn from tank 42, raised in pressure in pump 52 in order to be fed to secondary cooler 22 as a light cooling liquid 54.
  • the LNG may be transported by ship, truck or other transport means.
  • FIG. 2 is an example of the process which generates LNG though direct condensation, but does not uses the bottoms liquid as a source of the product.
  • a natural gas stream 2 is introduced into a simple PSA 6 wherein a portion of the water is removed producing a dry natural gas stream 8 with a dew point below ⁇ 50°C and a purge stream 10 containing the removed moisture.
  • Stream 8 is then cooled to _ 50°C in an indirect heat exchanger 12 to produce a chilled dry natural gas stream 14.
  • Stream 14 is then introduced into the quench column 16 wherein it is cooled to -100°C through direct contact with a primary cooling liquid and a substantial portion of the heavy components within stream 14 condense and solidify into the dirty heavy bottom liquid 18.
  • a portion of the primary cooling liquid is evaporated during this process and mixes with the light components of stream 14 and exits the quench column 16 as the chilled medium gas 20.
  • Stream 20 is then further cooled through direct contact in a secondary cooler 22 with a secondary cooling liquid, removing further impurities such as C 2 and C 3 to producing a medium bottom liquid 24 which is fed to the quench column 16 to provide a portion of the primary cooling liquid.
  • the solids in stream 18 are removed through the use of a filter 28 producing a heavy liquid 30 and a solid waste stream 32.
  • Stream 30 is then raised in pressure in recycle pump 34 and fed as heavy cooling liquid 36 to quench column 16 where it forms part of the primary cooling fluid.
  • the remaining uncondensed portion of stream 20 exits the secondary cooler 22 as a light chilled gas 26 and is fully condensed in a liquefier 38 and fed as a light liquid stream 40 to a storage tank 42.
  • a draw stream 44 is removed from tank 42, reduced in pressure by regulator 46 and delivered as liquefied natural gas 48.
  • a light liquid draw stream 50 is withdrawn from tank 42, raised in pressure in pump 52 in order to be fed to secondary cooler 22 as a light cooling liquid 54.
  • a secondary light liquid draw stream 56 is removed from tank 42, raised in pressure in pump 58 to form light condensing fluid 60 and introduced into direct condenser 62.
  • the light chilled gas 26 is also introduced into the direct condenser 62 where the majority of the stream is condensed forming light condensate 64.
  • Stream 64 is cooled even further in exchanger 66 to form stream 40. Any incondensable gases leave direct condenser 62 as purge 68.
  • FIG. 3 does generate LNG though direct condensation and uses the bottoms liquid as a source of the product.
  • natural gas stream 2 is introduced into a simple PSA 6 wherein a portion of the water is removed producing a dry natural gas stream 8 with a dew point below -50°C and a purge stream 10 containing the removed moisture.
  • Stream 8 is then cooled to -50°C in an indirect heat exchanger 12 to produce a chilled dry natural gas stream 14.
  • Stream 14 is then introduced into the quench column 16 wherein it is cooled to -100°C through direct contact with a primary cooling liquid and a substantial portion of the heavy components within stream 14 condense and solidify into the dirty heavy bottom liquid 18.
  • a portion of the cooling is evaporated during this process and mixes with the light components of stream 14 and exits the quench column 16 as the chilled medium gas 20.
  • Stream 20 chilled medium gas 20 is instead sent to direct condenser 62 to produce the medium bottom liquid 24.
  • Medium bottom liquid 24 which is fed to the quench column 16 to provide a portion of the primary cooling liquid.
  • the solids in stream 18 are removed through the use of a filter 28 producing a heavy liquid 30 and a solid waste stream 32.
  • Heavy liquid stream 30 is cooled in exchanger 66 to form stream 40 and be fed to tank 42.
  • the remaining uncondensed portion of stream 20 exits the secondary cooler 22 as a light chilled gas 26 and is fully condensed in a liquefier 38 and fed as a light liquid stream 40 to a storage tank 42.
  • a draw stream 44 is removed from tank 42, reduced in pressure by regulator 46 and delivered as liquefied natural gas 48. Meanwhile, a light liquid draw stream 50 is withdrawn from tank 42, raised in pressure in pump 52 in order to be fed to secondary cooler 22 as a light cooling liquid 54.
  • a first embodiment of the invention is a process for liquefaction of natural gas, the process comprising a) sending the cooled natural gas stream to a quench unit; b) sending a quantity of liquefied natural gas to the quench unit to be combined with the cooled natural gas steam to produce a bottoms stream comprising a liquid stream comprising solid impurities and a top stream comprising methane and incondensable impurities; and c) cooling the bottoms stream to produce liquefied natural gas.
  • An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the natural gas stream is cooled to a temperature from 0° to -100°C to produce a cooled natural gas stream.
  • An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising sending the bottoms stream to a unit to remove the solid impurities to a produce a purified bottoms stream.
  • An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein a portion of the bottom stream is returned to the quench unit.
  • An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein before the natural gas stream is cooled, at least a portion of water within the natural gas stream is removed.
  • An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the natural gas stream is cooled to a temperature of -25° to -75°C.
  • An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the natural gas stream is cooled to a temperature of -55° to -60°C.
  • An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the solid impurities are selected from the group consisting of carbon dioxide, C 5 and C 6 hydrocarbons and water.
  • An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the incondensable impurities are selected from the group consisting of nitrogen, oxygen and hydrogen.
  • An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the bottoms stream is at a temperature from -75° to -120°C.
  • An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the bottoms stream is at a temperature from -90° to -100°C.
  • a second embodiment of the invention is a system for producing liquefied natural gas from a supply of natural gas, comprising a) a device for supplying a stream of natural gas; b) a separation device to remove water from the stream of natural gas to produce a partially dried stream of natural gas; c) a means for feeding the partially dried stream of natural gas to a chilling device and then to a column; d) a means for feeding a quantity of a chilled liquid to the column where the chilled liquid and the partially dried stream of natural gas are present in the column and a means to vent a purge stream from the quench tower; e) a means to transport a combination of the chilled liquid and the partially dried stream of natural gas to a particle removal unit; f) a means to transport a purified stream from the filter unit to a chiller to produce liquefied natural gas; and g) a means to send the liquefied natural gas to a storage device.
  • An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph wherein the separation device removes additional contaminants from the stream of natural gas.
  • An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph wherein the column is a quench tower.
  • An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph wherein the chilled liquid is a quantity of liquefied natural gas.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Separation By Low-Temperature Treatments (AREA)

Abstract

La présente invention concerne un procédé et un système pour la production de gaz naturel liquéfié (GNL) à partir de gaz naturel. Le gaz naturel est d'abord partiellement purifié par élimination d'eau et d'autres contaminants, puis il est partiellement refroidi afin de congeler certains contaminants et de permettre la production d'un courant de purge chargé d'éliminer d'autres contaminants. Ces contaminants peuvent être extraits du courant. Le procédé offre les avantages d'être peu coûteux et de mieux éliminer les contaminants.
PCT/US2014/048522 2013-07-31 2014-07-29 Procédé destiné à la liquéfaction de gaz naturel WO2015017357A1 (fr)

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US201361860319P 2013-07-31 2013-07-31
US61/860,319 2013-07-31
US14/338,982 US20150033793A1 (en) 2013-07-31 2014-07-23 Process for liquefaction of natural gas
US14/338,982 2014-07-23

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WO2017093377A1 (fr) 2015-12-03 2017-06-08 Shell Internationale Research Maatschappij B.V. Procédé de liquéfaction de courant gazeux contenant des hydrocarbures, contaminé au co2
WO2017162566A1 (fr) 2016-03-21 2017-09-28 Shell Internationale Research Maatschappij B.V. Procédé et système de liquéfaction de flux d'alimentation de gaz naturel
US10151528B2 (en) 2013-04-11 2018-12-11 Shell Oil Company Method of liquefying a contaminated hydrocarbon-containing gas stream
US10267559B2 (en) 2015-04-10 2019-04-23 Chart Energy & Chemicals, Inc. Mixed refrigerant liquefaction system and method
US10619918B2 (en) 2015-04-10 2020-04-14 Chart Energy & Chemicals, Inc. System and method for removing freezing components from a feed gas

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US10788259B1 (en) * 2015-12-04 2020-09-29 Chester Lng, Llc Modular, mobile and scalable LNG plant

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US10151528B2 (en) 2013-04-11 2018-12-11 Shell Oil Company Method of liquefying a contaminated hydrocarbon-containing gas stream
US10267559B2 (en) 2015-04-10 2019-04-23 Chart Energy & Chemicals, Inc. Mixed refrigerant liquefaction system and method
US10619918B2 (en) 2015-04-10 2020-04-14 Chart Energy & Chemicals, Inc. System and method for removing freezing components from a feed gas
US12000653B2 (en) 2015-04-10 2024-06-04 Chart Energy & Chemicals, Inc. System and method for removing freezing components from a feed gas
WO2017093377A1 (fr) 2015-12-03 2017-06-08 Shell Internationale Research Maatschappij B.V. Procédé de liquéfaction de courant gazeux contenant des hydrocarbures, contaminé au co2
US10871323B2 (en) 2015-12-03 2020-12-22 Shell Oil Company Method of liquefying a CO2 contaminated hydrocarbon-containing gas stream
WO2017162566A1 (fr) 2016-03-21 2017-09-28 Shell Internationale Research Maatschappij B.V. Procédé et système de liquéfaction de flux d'alimentation de gaz naturel

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