Hydrothermal liquefaction heat recovery process

Abstract

A hydrothermal liquefaction (HTL) reactor system can comprise a biomass slurry source, a mixing vessel, a pump, a HTL reactor section, a pressure letdown valve, and a vapor-liquid disengagement vessel. The mixing vessel can mix a biomass slurry stream received from the biomass slurry source with a vaporized water and gas byproducts stream. The pump can pressurize a biomass slurry stream received from the mixing vessel. The HTL reactor section can produce a product mixture stream from a biomass slurry stream received from the pump. The pressure letdown valve can reduce the pressure of a product mixture stream received from the HTL reactor section. The vapor-liquid disengagement vessel can separate vaporized water and gas byproducts from a product mixture stream received from the pressure letdown valve, wherein the separated vaporized water and gas byproducts can form the vaporized water and gas byproducts stream received by the mixing vessel.

1 . A hydrothermal liquefaction (HTL) reactor system comprising:
 a biomass slurry source;   a mixing vessel disposed downstream of the biomass slurry source, wherein the mixing vessel is configured to mix a biomass slurry stream received from the biomass slurry source with a vaporized water and gas byproducts stream;   a pump disposed downstream of the mixing vessel, wherein the pump is configured to pressurize a biomass slurry stream received from the mixing vessel;   a HTL reactor section disposed downstream of the pump, wherein the HTL reactor section is configured to produce a product mixture stream from a biomass slurry stream received from the pump;   a pressure letdown valve disposed downstream of the HTL reactor section, wherein the pressure letdown valve is configured to reduce the pressure of a product mixture stream received from the HTL reactor section; and   a vapor-liquid disengagement vessel disposed downstream of the pressure letdown valve, wherein the vapor-liquid disengagement vessel is configured to separate vaporized water and gas byproducts from a product mixture stream received from the pressure letdown valve, and wherein the separated vaporized water and gas byproducts form the vaporized water and gas byproducts stream received by the mixing vessel.   
     
     
         2 . The HTL reactor system of  claim 1 , wherein the HTL reactor section comprises an autothermal HTL reactor. 
     
     
         3 . The HTL reactor system of  claim 1 , wherein the mixing vessel is a first mixing vessel and the HTL reactor system further comprises a second mixing vessel disposed downstream of the pump. 
     
     
         4 . The HTL reactor system of  claim 3 , wherein the second mixing vessel is configured to provide a vaporized water and gas byproducts stream to the first mixing vessel. 
     
     
         5 . The HTL reactor system of  claim 1 , wherein:
 the pressure letdown valve is a second pressure letdown valve,   the vapor-liquid disengagement vessel is a second vapor-liquid disengagement vessel,   the HTL reactor system further comprises a first vapor-liquid disengagement vessel disposed upstream of the second pressure letdown valve, and   the HTL reactor system further comprises a first pressure letdown valve disposed upstream of the first vapor-liquid disengagement vessel.   
     
     
         6 . The HTL reactor system of  claim 5 , further comprising an excess steam outlet coupled to an outlet of the first vapor-liquid disengagement vessel. 
     
     
         7 . The HTL reactor system of  claim 1 , further comprising a heat exchanger disposed downstream of the HTL reactor section, and wherein the heat exchanger is configured to recover heat from the product mixture stream. 
     
     
         8 . The HTL reactor system of  claim 7 , wherein:
 the heat exchanger is a first heat exchanger in a heat transfer liquid circuit of the HTL reactor system,   the heat transfer liquid circuit further comprises a second heat exchanger disposed upstream of the HTL reactor section, and   the heat transfer liquid circuit is configured to circulate heat transfer liquid heated in the first heat exchanger to the second heat exchanger to heat a biomass slurry stream entering the HTL reactor section.   
     
     
         9 . The HTL reactor system of  claim 8 , wherein:
 the pressure of the biomass slurry stream entering the HTL reactor section is a first pressure,   the pressure of the heat transfer liquid circulating through the heat transfer liquid circuit is a second pressure, and   the first pressure is higher than the second pressure.   
     
     
         10 . A hydrothermal liquefaction (HTL) process comprising:
 in a mixing vessel, mixing a biomass slurry stream with a vaporized water and gas byproducts stream to heat the biomass slurry stream;   pressurizing a biomass slurry stream received from the mixing vessel;   flowing the biomass slurry stream through a HTL reactor to produce a product mixture stream including biocrude oil and water; and   in a flashing process, reducing the pressure of the product mixture stream to produce the vaporized water and gas byproducts stream.   
     
     
         11 . The HTL process of  claim 10 , wherein:
 the vaporized water and gas byproducts stream is a first vaporized water and gas byproducts stream,   the process further comprises, after pressurizing the biomass slurry stream but before flowing the biomass slurry stream through the HTL reactor, mixing the biomass slurry stream with a second vaporized water and gas byproducts stream in a second mixing vessel.   
     
     
         12 . The HTL process of  claim 11 , wherein mixing the biomass slurry stream with the second vaporized water and gas byproducts stream forms a third vaporized water and gas byproducts stream, and wherein mixing the biomass slurry stream with the first vaporized water and gas byproducts stream further comprises mixing the biomass slurry stream with the third vaporized water and gas byproducts stream. 
     
     
         13 . The HTL process of  claim 11 , wherein:
 the flashing process is a second flashing process occurring in a second vapor-liquid disengagement vessel,   the process further comprises, before the second flashing process, reducing the pressure of the product mixture stream in a first flashing process occurring in a first vapor-liquid disengagement vessel to produce the second vaporized water and gas byproducts stream,   the product mixture stream subject to the first flashing process is received from the HTL reactor, and   the product mixture stream subject to the second flashing process is received from the first vapor-liquid disengagement vessel.   
     
     
         14 . The HTL process of  claim 13 , wherein the first flashing process vaporizes 5% to 50% of water in the product mixture stream. 
     
     
         15 . The HTL process of  claim 13 , wherein the second flashing process vaporizes 10% to 30% of water in the product mixture stream. 
     
     
         16 . The HTL process of  claim 10 , further comprising removing offgas from the mixing vessel, wherein the offgas comprises 25% to 45% CO 2 . 
     
     
         17 . The HTL process of  claim 10 , further comprising, before flowing the biomass slurry stream through the HTL reactor, transferring heat from a heat transfer liquid stream to the biomass slurry stream in a first heat exchanger. 
     
     
         18 . The HTL process of  claim 17 , further comprising, after flowing the biomass slurry stream through the HTL reactor:
 transferring heat from the product mixture stream to the heat transfer liquid stream in a second heat exchanger; and   circulating the heat transfer liquid stream from the second heat exchanger to the first heat exchanger.   
     
     
         19 . The HTL process of  claim 10 , further comprising, concurrently with flowing the biomass slurry stream through the HTL reactor, injecting oxygen into the HTL reactor. 
     
     
         20 . The HTL process of  claim 19 , further comprising, in the flashing process, producing an excess steam stream.