# US 10,480,851 B2 · Mixed refrigerant system and method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,480,851 B2 - Document ID: US10480851B2 - Status: Granted - Kind: B2 - Application number: 14/218,949 - Filed: 2014-03-18 - Published: 2014-09-18 - Granted: 2019-11-19 - Earliest claimed: 2013-03-15 - Assignees: Chart Energy & Chemicals, Inc. - Applicants: Chart Energy & Chemicals, Inc. - Inventors: Douglas A. Ducote, Jr.; Timothy P. Gushanas - Web page: https://patentgrep.com/patent/US10480851B2 ## CPC - F25J 1/0022: {Hydrocarbons, e.g. natural gas} - F25B 9/006: {the refrigerant containing more than one component (F25B9/004 takes precedence)} - F25J 1/0055: {originating from an incorporated cascade} - F25J 1/0212: {as a single flow MCR cycle} - F25J 1/0262: {Details of the cold heat exchange system (constructional details F25J5/00, construction of cold-exchangers in general F28)} - F25J 1/0291: {Refrigerant compression by combined gas compression and liquid pumping} - F25J 2220/64: Separating heavy hydrocarbons, e.g. NGL, LPG, C4+ hydrocarbons or heavy condensates in general - F25J 2290/32: Details on header or distribution passages of heat exchangers, e.g. of reboiler-condenser or plate heat exchangers - 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)} - F25B: REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS ## Abstract Provided are mixed refrigerant systems and methods and, more particularly, to a mixed refrigerant system and methods that provides greater efficiency and reduced power consumption. ## Claims ### Claim 1 A method for cooling a feed fluid, comprising: separating, in a high pressure separation device at the same pressure, a high pressure mixed refrigerant stream, said stream comprising two or more C1-C5 hydrocarbons and optionally N2, to form a high pressure vapor stream and a mid-boiling refrigerant liquid stream; cooling the high pressure vapor stream in a heat exchanger to form a mixed phase stream; separating the mixed phase stream with a cold vapor separator, to form a cold separator vapor stream and a cold separator liquid stream; condensing the cold separator vapor stream in the heat exchanger and flashing, to form a cold temperature refrigerant stream; subcooling at least a portion of the mid-boiling refrigerant liquid stream in a first heat exchange passage in the heat exchanger to a subcooled state and temperature, where the first heat exchange passage has a first heat exchange passage length, to form a subcooled mid-boiling refrigerant liquid stream; subcooling the cold separator liquid stream in a second heat exchange passage in the heat exchanger to a subcooled state and temperature, where the second heat exchange passage has a second heat exchange passage length, prior to combination with the subcooled mid-boiling refrigerant liquid stream to form a subcooled cold separator liquid stream, wherein the first heat exchange passage is separate and distinct from the second heat exchange passage and the first heat exchange passage length is greater than the second heat exchange passage length; combining the subcooled mid-boiling refrigerant liquid stream and the subcooled cold separator liquid stream while the subcooled mid-boiling refrigerant liquid stream is at, or colder via expansion than, the temperature of the subcooled mid-boiling refrigerant liquid stream in the subcooled state and the subcooled cold separator liquid stream is at, or colder via expansion than, the temperature of the subcooled cold separator liquid stream in the subcooled state to form a middle temperature refrigerant stream; combining, in the heat exchanger, the middle temperature refrigerant stream with one of a cold temperature rejoined refrigerant stream and the cold temperature refrigerant stream, after the subcooled mid-boiling refrigerant liquid stream and the subcooled cold separator liquid stream are combined to form the middle temperature refrigerant stream, and warming, to form a vapor refrigerant return stream comprising the hydrocarbons and optional N2; and thermally contacting the feed fluid in the heat exchanger, to form a cooled feed fluid. ### Claim 2 (depends on 1) The method of claim 1 further comprising the step of expanding the combined subcooled cold separator liquid and subcooled mid-boiling refrigerant liquid streams to form the middle temperature refrigerant stream. ### Claim 3 (depends on 2) The method of claim 2 wherein the step of expanding the combined subcooled cold separator liquid and subcooled mid-boiling refrigerant liquid streams includes flashing the combined subcooled cold separator liquid and subcooled mid-boiling refrigerant liquid streams. ### Claim 4 (depends on 1) The method of claim 1 further comprising the steps of: cooling a high-boiling liquid refrigerant stream in the heat exchanger to form a subcooled high-boiling liquid refrigerant; expanding the subcooled high-boiling liquid refrigerant to form a pre-cool refrigerant stream; warming the pre-cool refrigerant stream to form a pre-cool refrigerant return stream that is vapor phase or mixed phase. ### Claim 5 (depends on 4) The method of claim 4 wherein the step of expanding the subcooled high-boiling liquid refrigerant to form a pre-cool refrigerant stream includes flashing the subcooled high-boiling liquid refrigerant. ### Claim 6 (depends on 5) The method of claim 5 further comprising the steps of separating the pre-cool refrigerant stream into a pre-cool vapor refrigerant stream and a pre-cool liquid refrigerant stream and rejoining the pre-cool vapor refrigerant and pre-cool liquid refrigerant streams prior to warming. ### Claim 7 (depends on 4) The method of claim 4 further comprising the step of combining the pre-cool refrigerant stream with the combined middle temperature refrigerant and cold temperature refrigerant streams. ### Claim 8 (depends on 7) The method of claim 7 further comprising the steps of expanding the subcooled cold separator liquid stream and expanding the subcooled mid-boiling refrigerant liquid stream before combining the subcooled cold separator liquid stream and the subcooled mid-boiling refrigerant liquid stream. ### Claim 9 (depends on 8) The method of claim 8 wherein the step of expanding the subcooled cold separator liquid stream includes flashing the subcooled cold separator liquid stream and the step of expanding the subcooled mid-boiling refrigerant liquid stream includes flashing the subcooled mid-boiling refrigerant liquid stream. ### Claim 10 (depends on 7) The method of claim 7 further comprising the step of expanding the subcooled cold separator liquid stream. ### Claim 11 (depends on 7) The method of claim 7 further comprising the step of expanding the subcooled mid-boiling refrigerant liquid stream. ### Claim 12 (depends on 7) The method of claim 7 further comprising the step of expanding the combined subcooled cold separator liquid and subcooled mid-boiling refrigerant liquid streams to form the middle temperature refrigerant stream. ### Claim 13 (depends on 4) The method of claim 4 further comprising the step of expanding the combined subcooled cold separator liquid and subcooled mid-boiling refrigerant liquid streams to form the middle temperature refrigerant stream. ### Claim 14 (depends on 7) The method of claim 7 wherein the step of expanding the subcooled high-boiling liquid refrigerant to form a pre-cool refrigerant stream includes flashing the subcooled high-boiling liquid refrigerant and further comprising the steps of separating the pre-cool refrigerant stream into a pre-cool vapor refrigerant stream and a pre-cool liquid refrigerant stream and rejoining the pre-cool vapor refrigerant and pre-cool liquid refrigerant streams prior to combination with the middle temperature refrigerant and cold temperature refrigerant streams. ### Claim 15 (depends on 1) The method of claim 1 further comprising the steps of expanding the subcooled cold separator liquid stream and expanding the subcooled mid-boiling refrigerant liquid stream before combining the subcooled cold separator liquid stream and the subcooled mid-boiling refrigerant liquid stream. ### Claim 16 (depends on 15) The method of claim 15 wherein the step of expanding the subcooled cold separator liquid stream includes flashing the subcooled cold separator liquid stream and the step of expanding the subcooled mid-boiling refrigerant liquid stream includes flashing the subcooled mid-boiling refrigerant liquid stream. ### Claim 17 (depends on 16) The method of claim 16 further comprising the steps of combining the flashed subcooled cold separator liquid stream and the flashed subcooled mid-boiling refrigerant liquid stream and forming a middle temperature refrigerant liquid stream and a middle temperature refrigerant vapor stream and rejoining the middle temperature refrigerant liquid and middle temperature refrigerant vapor streams prior to combination with the cold temperature refrigerant stream. ### Claim 18 (depends on 1) The method of claim 1 further comprising the step of expanding the subcooled cold separator liquid stream. ### Claim 19 (depends on 1) The method of claim 1 further comprising the step of expanding the subcooled mid-boiling refrigerant liquid stream. ### Claim 20 (depends on 1) The method of claim 1 further comprising the steps of separating the cold temperature refrigerant stream to form a cold temperature liquid refrigerant stream and a cold temperature vapor refrigerant stream and rejoining the cold temperature liquid refrigerant stream and the cold temperature vapor refrigerant stream to form the cold temperature rejoined refrigerant stream, prior to combination with the middle temperature refrigerant stream. ### Claim 21 (depends on 1) The method of claim 1 wherein the cold separator liquid stream is colder than the mid-boiling refrigerant liquid stream. ### Claim 22 A method for cooling a feed fluid, comprising: separating, in a high pressure separation device at the same pressure, a high pressure mixed refrigerant stream, said stream comprising two or more C1-C5 hydrocarbons and optionally N2, to form a high pressure vapor stream and a mid-boiling refrigerant liquid stream; cooling the high pressure vapor stream in a heat exchanger to form a mixed phase stream; separating the mixed phase stream with a cold vapor separator, to form a cold separator vapor stream and a cold separator liquid stream; condensing the cold separator vapor stream in the heat exchanger and flashing, to form a cold temperature refrigerant stream; subcooling at least a portion of the mid-boiling refrigerant liquid stream in a first heat exchange passage in the heat exchanger to a subcooled state and temperature, where the first heat exchange passage has a first heat exchange passage length, to form a subcooled mid-boiling refrigerant liquid stream; subcooling the cold separator liquid stream in a second heat exchange passage in the heat exchanger to a subcooled state and temperature, where the second heat exchange passage has a second heat exchange passage length, prior to combination with the subcooled mid-boiling refrigerant liquid stream to form a subcooled cold separator liquid stream, wherein the first heat exchange passage is separate and distinct from the second heat exchange passage and the first heat exchange passage length is greater than the second heat exchange passage length; directing the subcooled mid-boiling refrigerant liquid stream and the subcooled cold separator liquid stream individually and directly, before or after expansion, to a mixing junction; combining the subcooled mid-boiling refrigerant liquid stream and the subcooled cold separator liquid stream while the subcooled mid-boiling refrigerant liquid stream is at, or colder via expansion than, the temperature of the subcooled mid-boiling refrigerant liquid stream in the subcooled state and the subcooled cold separator liquid stream is at, or colder via expansion than, the temperature of the subcooled cold separator liquid stream in the subcooled state at the mixing junction to form a middle temperature refrigerant stream; combining the middle temperature refrigerant stream and the cold temperature refrigerant stream in the heat exchanger, after the subcooled mid-boiling refrigerant liquid stream and the subcooled cold separator liquid stream are combined to form the middle temperature refrigerant stream, and warming, to form a vapor refrigerant return stream comprising the hydrocarbons and optional N2; and thermally contacting the feed fluid in the heat exchanger, to form a cooled feed fluid. ### Claim 23 (depends on 22) The method of claim 22 wherein the cold separator liquid stream is colder than the mid-boiling refrigerant liquid stream.