# US 10,502,482 B2 · Method for the production of liquefied natural gas > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,502,482 B2 - Document ID: US10502482B2 - Status: Granted - Kind: B2 - Application number: 15/465,634 - Filed: 2017-03-22 - Published: 2017-07-06 - Granted: 2019-12-10 - Earliest claimed: 2014-01-28 - Assignees: Dresser-Rand Company - Applicants: Dresser-Rand Company - Inventors: Daniel L. Ohart; Gregory W. Yonker - Web page: https://patentgrep.com/patent/US10502482B2 ## CPC - F25J 1/0022: {Hydrocarbons, e.g. natural gas} - F25J 1/0037: {of a return stream} - F25J 1/0045: {by vaporising a liquid return stream} - F25J 1/0052: {by vaporising a liquid refrigerant stream} - F25J 1/0208: {in combination with an internal quasi-closed refrigeration loop, e.g. with deep flash recycle loop (F25J1/021 takes precedence)} - F25J 1/0227: {within a refrigeration cascade} - F25J 1/0242: {Waste heat recovery, e.g. from heat of compression} - F25J 1/0254: {controlling particular process parameter, e.g. pressure, temperature} - F25J 1/0284: {Electrical motor as the prime mechanical driver} - F25J 1/0288: {using work extraction by mechanical coupling of compression and expansion of the refrigerant, so-called companders} - F25J 1/0292: {Refrigerant compression by cold or cryogenic suction of the refrigerant gas} - H02K 7/1815: {structurally associated with reciprocating piston engines (general aspects of generating sets, e.g. housing, F02B63/04)} - F25J 2205/60: using adsorption on solid adsorbents, e.g. by temperature-swing adsorption [TSA] at the hot or cold end - F25J 2220/66: Separating acid gases, e.g. CO2, SO2, H2S or RSH - F25J 2270/906: by heat driven absorption chillers - F25J 2290/62: Details of storing a fluid in a tank - 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 (cryogenic pumps F04B37/08; gas storage vessels, gas holders F17; filing vessels with, or discharging from vessels, compressed, liquefied or solidified gases F17C; refrigeration machines, plants, or systems F25B)} - H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53}) ## Abstract A system and method for producing liquefied natural gas are provided. The method may include compressing a process stream containing natural gas in a compression assembly to produce a compressed process stream. The method may also include removing non-hydrocarbons from the compressed process stream in a separator, and cooling the compressed process stream with a cooling assembly to thereby produce a cooled, compressed process stream containing natural gas in a supercritical state. The method may further include expanding a first portion and a second portion of the natural gas from the cooled, compressed process stream in a first expansion element and a second expansion element to generate a first refrigeration stream and a second refrigeration stream, respectively. The method may further include cooling the natural gas in the cooled, compressed process stream to a supercritical state with the first and second refrigeration streams to thereby produce the liquefied natural gas. ## Claims ### Claim 1 A method for producing liquefied natural gas, comprising: compressing a process stream containing natural gas from a natural gas source in a compression assembly fluidly coupled with the natural gas source to product a compressed process stream; removing one or more non-hydrocarbons from the compressed process stream in a separator fluidly coupled with the compression assembly; cooling the compressed process stream with a cooling assembly fluidly coupled with the compression assembly, thereby producing a cooled, compressed process stream containing the natural gas in a supercritical state; expanding a first portion of the natural gas in the cooled, compressed process stream in a first expansion element to generate a first refrigeration stream; expanding a second portion of the natural gas in the cooled, compressed process stream in a second expansion element to generate a second refrigeration stream; cooling at least a portion of the natural gas in the cooled, compressed process stream to a subcritical state with the first refrigeration stream and the second stream, thereby producing the liquefied natural gas; feeding the first refrigeration stream to the compression assembly as a first recycle stream; and combining the compressed first recycle stream with the compressed process stream downstream from the separator; feeding the second refrigeration stream to the compression assembly as a second recycle stream; and combining the compressed second recycle stream with the process stream upstream of the separator. ### Claim 2 (depends on 1) The method of claim 1, wherein the second expansion element is an expansion valve. ### Claim 3 (depends on 1) The method of claim 1, wherein the first expansion element is a turbo-expander. ### Claim 4 (depends on 3) The method of claim 3, further comprising: expanding the first portion of the cooled, compressed process stream in the turbo-expander to generate mechanical energy; and driving a compressor coupled with the turbo-expander with the mechanical energy to compress the first recycle stream. ### Claim 5 (depends on 1) The method of claim 1, wherein cooling the at least a portion of the natural gas in the cooled, compressed process stream to the subcritical state with the first refrigeration stream and the second refrigeration stream comprises: cooling the at least a portion of the natural gas in the cooled, compressed process stream in a first heat exchanger with the first refrigeration stream; and cooling the at least a portion of the natural gas in the cooled, compressed process stream in a second heat exchanger with the second refrigeration stream. ### Claim 6 (depends on 1) The method of claim 1, wherein the cooling assembly includes a mechanical chiller configured to receive and be driven by electrical energy. ### Claim 7 (depends on 1) The method of claim 1, wherein compressing the process stream in the compression assembly comprises: generating heat from the compression of the process stream; and absorbing at least a portion of the heat generated from the compression of the process stream with a cooler of the compression assembly. ### Claim 8 (depends on 1) The method of claim 1, wherein removing the one or more non-hydrocarbons from the compressed process stream in the separator comprises removing water and carbon dioxide from the natural gas in the separator at a pressure greater than about 1,000 kPa. ### Claim 9 A method for producing liquefied natural gas, comprising: compressing natural gas from a natural gas source in a compression assembly fluidly coupled with the natural gas source; removing water and carbon dioxide from the natural gas in a separator fluidly coupled with the compression assembly; cooling the natural gas to supercritical natural gas with a mechanical chiller configured to receive and be drive by electrical energy; expanding a first portion of the supercritical natural gas in a first expansion element to generate a first refrigeration stream; expanding a second portion of the supercritical natural gas in a second expansion element to generate a second refrigeration stream; and cooling the remaining supercritical natural gas to subcritical natural gas with the first refrigeration stream and the second refrigeration stream, thereby producing the liquefied natural gas; feeding the first refrigeration stream to the compression assembly as a first recycle stream; combining the compressed first recycle stream with the natural gas downstream from the separator; feeding the second refrigeration stream to the compression assembly as a second recycle stream; and combining the compressed second recycle stream with the natural gas upstream of the separator. ### Claim 10 (depends on 9) The method of claim 9, wherein the first expansion element is a turbo-expander, and the second expansion element is an expansion valve. ### Claim 11 (depends on 9) The method of claim 9, further comprising removing water and carbon dioxide from the natural gas in the separator at a pressure greater than about 1,000 kPa. ### Claim 12 (depends on 9) The method of claim 9, further comprising: combusting a portion of the natural gas from the natural gas source in an internal combustion engine to produce mechanical energy; generating the electrical energy in a generator operatively coupled with the internal combustion engine; and directing at least a portion of the electrical energy to the mechanical chiller. ### Claim 13 (depends on 9) The method of claim 9, wherein cooling the remaining supercritical natural gas to the subcritical natural gas with the first refrigeration stream and the second refrigeration stream comprises: cooling the remaining supercritical natural gas with the first refrigeration stream in a first heat exchanger; and cooling the remaining supercritical natural gas with the second refrigeration stream in a second heat exchanger.