Hydrothermal Liquefaction Heat Recovery Process

This application claims the benefit of the earlier filing dates of U.S. Provisional Patent Application No. 63/491,937, filed Mar. 23, 2023, and U.S. Provisional Patent Application No. 63/414,293, filed Oct. 7, 2022. The entire disclosures of U.S. Patent Application Nos. 63/491,937 and 63/414,293 are each incorporated by reference herein in their entireties.

This invention was made with Government support under Contract DE-AC0576RL01830 awarded by the U.S. Department of Energy. The Government has certain rights in the invention.

The present disclosure relates to hydrothermal liquefaction processes and systems for producing biocrude using steam heat recovery.

Hydrothermal liquefaction (HTL) is a processing technique than can convert a wide range of waste biological materials into a hydrocarbon liquid with similar properties to crude oil, often referred to as “biocrude.” Many HTL systems comprise heat exchangers for heating the waste biological materials, but such heat exchangers can be subject to fouling due to the presence of salt and COin the waste biological materials. Fouling on heat exchangers and other hot surfaces can decrease HTL energy efficiency by restricting flow and increasing pressure loss. Furthermore, many HTL systems operate at high temperatures and pressures, requiring heat exchangers with extremely thick metal walls which increase the cost of the HTL systems. Finally, many HTL systems require heat exchangers with large heat transfer surface areas due to the high viscosity of process fluids flowing through the HTL systems. The high viscosity of HTL process fluids results in laminar flow with poor heat transport properties and large temperature gradients near heat transfer surfaces.

Accordingly, a need exists for improved hydrothermal liquefaction processes and systems that address such deficiencies.

The present disclosure relates to apparatuses, systems, methods, and processes pertaining to hydrothermal liquefaction using vaporized water and hot byproduct gases from the HTL process as a heat exchange medium.

In some examples, a hydrothermal liquefaction (HTL) reactor system can comprise a biomass slurry source.

In some examples, the HTL reactor system can comprise a mixing vessel disposed downstream of the biomass slurry source, wherein the mixing vessel can be configured to mix a biomass slurry stream received from the biomass slurry source with a vaporized water and gas byproducts stream.

In some examples, the HTL reactor system can comprise a pump disposed downstream of the mixing vessel, wherein the pump can be configured to pressurize a biomass slurry stream received from the mixing vessel.

In some examples, the HTL reactor system can comprise a HTL reactor section disposed downstream of the pump, wherein the HTL reactor section can be configured to produce a product mixture stream from a biomass slurry stream received from the pump.

In some examples, the HTL reactor system can comprise a pressure letdown valve disposed downstream of the HTL reactor section, wherein the pressure letdown valve can be configured to reduce the pressure of a product mixture stream received from the HTL reactor section.

In some examples, the HTL reactor system can comprise a vapor-liquid disengagement vessel disposed downstream of the pressure letdown valve, wherein the vapor-liquid disengagement vessel can be 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 can form the vaporized water and gas byproducts stream received by the mixing vessel.

In some examples, the HTL reactor section can comprise an autothermal HTL reactor.

In some examples, the mixing vessel can be a first mixing vessel and the HTL reactor system can further comprise a second mixing vessel disposed downstream of the pump.

In some examples, the second mixing vessel can be configured to provide a vaporized water and gas byproducts stream to the first mixing vessel.

In some examples, the pressure letdown valve can be a second pressure letdown valve and the vapor-liquid disengagement vessel can be a second vapor-liquid disengagement vessel.

In some examples, the HTL reactor system can further comprise a first vapor-liquid disengagement vessel disposed upstream of the second pressure letdown valve and the HTL reactor system can further comprise a first pressure letdown valve disposed upstream of the first vapor-liquid disengagement vessel.

In some examples, the HTL reactor system can further comprise an excess steam outlet coupled to an outlet of the first vapor-liquid disengagement vessel.

In some examples, the HTL reactor system can further comprise a heat exchanger disposed downstream of the HTL reactor section.

In some examples, the heat exchanger can be configured to recover heat from the product mixture stream.

In some examples, the heat exchanger can be a first heat exchanger in a heat transfer liquid circuit of the HTL reactor system,

In some examples, the heat transfer liquid circuit can further comprise a second heat exchanger disposed upstream of the HTL reactor section.

In some examples, the heat transfer liquid circuit can be 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.

In some examples, the pressure of the biomass slurry stream entering the HTL reactor section can be a first pressure and the pressure of the heat transfer liquid circulating through the heat transfer liquid circuit can be a second pressure.

In some examples, the first pressure can be higher than the second pressure.

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

In one representative example, a hydrothermal liquefaction (HTL) process can comprise, in a mixing vessel, mixing a biomass slurry stream with a vaporized water and gas byproducts stream to heat the biomass slurry stream.

In some examples, the HTL process can comprise pressurizing a biomass slurry stream received from the mixing vessel.

In some examples, the HTL process can comprise flowing the biomass slurry stream through a HTL reactor to produce a product mixture stream including biocrude oil and water.

In some examples, the HTL process can comprise, in a flashing process, reducing the pressure of the product mixture stream to produce the vaporized water and gas byproducts stream.

In some examples, mixing the biomass slurry stream with the second vaporized water and gas byproducts stream can form a third vaporized water and gas byproducts stream.

In some examples, mixing the biomass slurry stream with the first vaporized water and gas byproducts stream can further comprise mixing the biomass slurry stream with the third vaporized water and gas byproducts stream.

In some examples, the flashing process can be a second flashing process occurring in a second vapor-liquid disengagement vessel.

In some examples, the HTL process further can comprise, 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.

In some examples, the product mixture stream subject to the first flashing process can be received from the HTL reactor.

In some examples, the product mixture stream subject to the second flashing process can be received from the first vapor-liquid disengagement vessel.

In some examples, the first flashing process can vaporize 5% to 50% of water in the product mixture stream.

In some examples, the second flashing process can vaporize 10% to 30% of water in the product mixture stream.

In some examples, the HTL process can further comprise removing offgas from the mixing vessel.

In some examples, the offgas can comprise 25% to 45% CO.

In some examples, the HTL process can further comprise, 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.

In some examples, the HTL process which can further comprise, 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.

In some examples, the HTL process which can further comprise, after flowing the biomass slurry stream through the HTL reactor, circulating the heat transfer liquid stream from the second heat exchanger to the first heat exchanger.

In some examples, the HTL process can further comprise, concurrently with flowing the biomass slurry stream through the HTL reactor, injecting oxygen into the HTL reactor.

In some examples, the HTL process can further comprise, in the flashing process, producing an excess steam stream.

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

In one representative examples, a hydrothermal liquefaction (HTL) process can comprise: 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

In some examples, a HTL reactor system and/or process can comprise one or more of the components and/or unit operations recited in Examples 1-20 below.

The foregoing and other objects, features, and advantages of the disclosed technology will become more apparent from the following detailed description, which proceeds with reference to the accompanying figures.

For purposes of this description, certain aspects, advantages, and novel features of the embodiments of this disclosure are described herein. The disclosed methods, apparatus, and systems should not be construed as being limiting in any way. Instead, the present disclosure is directed toward all novel and nonobvious features and aspects of the various disclosed embodiments, alone and in various combinations and sub-combinations with one another. The methods, apparatus, and systems are not limited to any specific aspect or feature or combination thereof, nor do the disclosed embodiments require that any one or more specific advantages be present or problems be solved.