EP4359352A1 - Intégration rentable de liquéfaction hydrothermale et de traitement des eaux usées par oxydation humide - Google Patents

Intégration rentable de liquéfaction hydrothermale et de traitement des eaux usées par oxydation humide

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Publication number
EP4359352A1
EP4359352A1 EP21743373.9A EP21743373A EP4359352A1 EP 4359352 A1 EP4359352 A1 EP 4359352A1 EP 21743373 A EP21743373 A EP 21743373A EP 4359352 A1 EP4359352 A1 EP 4359352A1
Authority
EP
European Patent Office
Prior art keywords
htl
wet oxidation
product stream
reactor
heat
Prior art date
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Pending
Application number
EP21743373.9A
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German (de)
English (en)
Inventor
Ib Johannsen
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Circlia Nordic ApS
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Circlia Nordic ApS
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Publication date
Application filed by Circlia Nordic ApS filed Critical Circlia Nordic ApS
Publication of EP4359352A1 publication Critical patent/EP4359352A1/fr
Pending legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
    • C10G1/00—Production of liquid hydrocarbon mixtures from oil-shale, oil-sand, or non-melting solid carbonaceous or similar materials, e.g. wood, coal
    • C10G1/04—Production of liquid hydrocarbon mixtures from oil-shale, oil-sand, or non-melting solid carbonaceous or similar materials, e.g. wood, coal by extraction
    • C10G1/047—Hot water or cold water extraction processes
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F11/00—Treatment of sludge; Devices therefor
    • C02F11/06—Treatment of sludge; Devices therefor by oxidation
    • C02F11/08—Wet air oxidation
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
    • C10G1/00—Production of liquid hydrocarbon mixtures from oil-shale, oil-sand, or non-melting solid carbonaceous or similar materials, e.g. wood, coal
    • C10G1/02—Production of liquid hydrocarbon mixtures from oil-shale, oil-sand, or non-melting solid carbonaceous or similar materials, e.g. wood, coal by distillation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F11/00—Treatment of sludge; Devices therefor
    • C02F11/12—Treatment of sludge; Devices therefor by de-watering, drying or thickening
    • C02F11/121—Treatment of sludge; Devices therefor by de-watering, drying or thickening by mechanical de-watering
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F11/00—Treatment of sludge; Devices therefor
    • C02F11/12—Treatment of sludge; Devices therefor by de-watering, drying or thickening
    • C02F11/121—Treatment of sludge; Devices therefor by de-watering, drying or thickening by mechanical de-watering
    • C02F11/127—Treatment of sludge; Devices therefor by de-watering, drying or thickening by mechanical de-watering by centrifugation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2209/00—Controlling or monitoring parameters in water treatment
    • C02F2209/02—Temperature
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2301/00—General aspects of water treatment
    • C02F2301/04—Flow arrangements
    • C02F2301/046—Recirculation with an external loop
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2301/00—General aspects of water treatment
    • C02F2301/06—Pressure conditions
    • C02F2301/066—Overpressure, high pressure

Definitions

  • the invention relates to methods and systems for thermochemical processing of lignocellulosic biomass, in general, and to hydrothermal liquefaction (HTL) in particular.
  • HTL hydrothermal liquefaction
  • Hydrothermal Liquefaction (HTL) processes provide efficient conversion of biomass including high value feedstocks such as wood and straw as well as low or negative value feedstocks such as sewage sludge and manure.
  • HTL systems can be configured in many different ways but generally produce a primary product such as bio crude oil, a combustible gas side stream and a significant amount of conversion product recovered as an aqueous phase with soluble organic constituents including organic acids, alcohols, aldehydes, phenols, furfural derivatives and nitrogen heterocyclic components.
  • part of the aqueous product is perpetually recycled, along with some portion of the product oil stream, whereby aqueous organic solutes are eventually converted to oil, gas and char.
  • HTL processes where product oil is not recycled produce an aqueous wastewater fraction which is typically a portion of the aqueous product stream that is removed while the remainder is recycled.
  • the feed stream is subject to only one pass through a thermochemical reactor, with no recycling of aqueous product.
  • HTL aqueous product i.e., wastewater
  • requires further processing because it is enriched in organic pollutants which act as inhibitors of various metabolic processes in nature. For review, see Leng 2018.
  • HTL wastewater is typically very high in chemical oxygen demand (COD). These high COD levels render classical aerobic biological wastewater treatment approaches to be prohibitively expensive. In a recent technoeconomic analysis the cost of classical wastewater treatment units for HTL wastewater were 2-3 times more costly than the HTL process plant itself. See Van Dyk et al, 2019. A variety of biological approaches to treatment and “valorization” of HTL wastewater streams have been reported. For review see Gu 2019. Anaerobic digestion to biomethane has been promising in theory but difficult to achieve in practice due to the inhibitory effect of HTL wastewater solutes. See e.g. Si 2018. Electrolytic conversion of HTL wastewater has been proposed, although this consumes energy without contributing any value to the HTL process. See WO2016169927.
  • thermochemical processing has also been proposed, with an aim of valorization, particularly including hydrothermal gasification of HTL wastewater. See Xu 2019, and see CN1066938. However, technoeconomic studies indicate that this approach will also prove prohibitively costly. See e.g. Zhu 2019.
  • HTL wastewater can be efficiently treated using a thermochemical wet oxidation process where compressed air or oxygen is added to an aqueous feedstock under high pressure and temperature with or without added catalyst.
  • Wet oxidation is widely used to treat problematic wastewater streams rich in bio-resistant organic pollutants. Residual COD remaining in the process stream after wet oxidation is typically readily digestible by ordinary anaerobic digestion. For reviews see Bhargava 2006 and see He 2007.
  • the wet oxidation process is highly exothermic and the resulting process heat can be “harvested” to provide some of the energy required for the underlying endothermic HTL process.
  • HTC hydrothermal carbonization
  • aqueous filtrate having low particulate content is subject to wet oxidation and the resulting flash steam is used to pre-heat the feed stream to a process temperature of 200° C.
  • Both HTL conversion of the feed stream and also wet oxidation of the aqueous product stream can be conducted in a simple continuous process in tubular reactors arranged co- or counter-current in direct thermal contact via a heat exchange system.
  • Separate HTL and aqueous phase heat exchangers provide efficient pre-heating of both the feed stream and the aqueous product stream.
  • the invention relates in a first aspect to a hydrothermal liquefaction (HTL) system
  • HTL hydrothermal liquefaction
  • a hydrothermal liquefaction (HTL) system comprising: an inlet unit for aqueous slurries of biomass, a high pressure pumping system providing an outlet pressure of at least 100 bar in communication with the inlet unit, a continuous HTL reactor adapted to process biomass feedstocks at temperature within the range 300 to 425° C so as to produce an HTL product stream, an HTL heat exchanger, adapted to transfer heat from the HTL product stream to the HTL feed stream, a solid-liquid separation system adapted to operate under pressure at temperature within the range 200 to 425° C so as to separate solids from the HTL product stream, a separator adapted to recover a separate aqueous phase from the solid-liquid separated HTL product stream, a continuous wet oxidation reactor adapted to process at temperature within the range 300 to 425° C the aqueous phase obtained from the solid-
  • the output of the solid-liquid separation system is a solid-liquid separated HTL product stream.
  • An advantage of the present invention may be that an effective separation of solids from the HTL product stream, e.g. including precipitated salts, may be obtained, e.g. without inhibiting the operation of the wet oxidation reactor. Utilization of certain specific characteristics of water within the temperature range of 300 to 425 degrees Celsius in the HTL reactor, such as low viscosity and/or low density, allows an effective separation e.g. by filtration or other means.
  • the high pressure pumping system is arranged to provide an outlet pressure of at least 100 bar and at most 400 bar, such as at least 100 bar and at most 350 bar.
  • the HTL reactor and the wet oxidation reactor are each tubular reactors arranged within a heat exchange system by being surrounded by a series of heat transfer clamps made from a solid matrix of heat conducting material where each individual heat transfer clamp comprises support formations that position and support the tubular reactor.
  • the HTL reactor and the wet oxidation reactor each comprise separate tubular sections into which the HTL and wet oxidation feed streams are divided.
  • the series of heat transfer clamps forms a circular array.
  • the inlet unit is in fluid communication with a stirred feed buffer tank.
  • the invention relates in a second aspect to a hydrothermal liquefaction (HTL) system comprising: an inlet unit for aqueous slurries of biomass, a high pressure pumping system providing an outlet pressure of at least 100 bar in communication with the inlet unit, a continuous HTL reactor adapted to process biomass feedstocks at temperature within the range 300 to 425° C so as to produce an HTL product stream, an HTL heat exchanger, adapted to transfer heat from the HTL product stream to the HTL feed stream, a solid-liquid separation system adapted to operate under pressure at temperature within the range 200 to 425° C so as to separate solids from the HTL product stream, a separator adapted to recover a separate aqueous phase from the solid-liquid separated HTL product stream, a continuous wet oxidation reactor adapted to process at temperature within the range 300 to 425° C the aqueous phase obtained
  • the output of the solid-liquid separation system is a solid-liquid separated HTL product stream.
  • the heat transfer medium is high pressure steam, high pressure compressed water, hot oil or molten salt.
  • the solid- liquid separation system comprises a filtration system.
  • the solid-liquid separation system is a filtration system.
  • a filtration system may e.g. be characterized by having one or more filter element(s) with a certain screen size or mesh size.
  • the filtration system comprises a filter element having a screen size of no more than 10 micrometer, such as no more than 8 micrometer, such as no more than 5 micrometer.
  • the filtration system may have a filter rate of at least 98% removal of solids with a particles size of 5 micrometer or more.
  • the filtration system may have a filter rate of 100% removal of solids with a particles size of 18 micrometer or more.
  • the solid-liquid separation system comprises a hydrocyclone.
  • the solid-liquid separation system is a hydrocyclone.
  • the solid-liquid separation system comprises a centrifuge.
  • the solid-liquid separation system is a centrifuge.
  • the solid-liquid separation system is selected from the group consisting of a filtration system, a hydrocyclone, a centrifuge, or any combination thereof.
  • the solids separated by the solid-liquid separation system comprise precipitated salts from the HTL product stream.
  • the precipitated salts from the HTL product stream comprises divalent salts and trivalent salts. In an embodiment of the invention, the precipitated salts from the HTL product stream further comprises monovalent salts.
  • any embodiment of the first aspect of the invention may be combined with the second aspect of the invention, and vice versa.
  • the invention further relates in a third aspect to a method of hydrothermal liquefaction (HTL) comprising the steps of: providing an HTL biomass feed stream, conducting continuous HTL conversion of the HTL feed stream at temperature within the range 300 to 425° C in such manner as to produce an HTL product stream which is separated under pressure at temperature within the range 200 to 425° C so as to separate precipitates and which is subsequently separated into an aqueous product stream and an oil product stream, and conducting concurrent continuous or semi-continuous wet oxidation at temperature within the range 300 to 425° C of all or some portion of the HTL aqueous product stream, wherein heat produced by the wet oxidation process is used to heat the HTL feed stream.
  • HTL hydrothermal liquefaction
  • heat produced by the wet oxidation process is used to heat the HTL feed stream by integrating a separate HTL reactor and a wet oxidation reactor in a co- or counter-current arrangement whereby the reactors are in direct thermal contact via a heat exchange system.
  • the wet oxidation process is conducted at a temperature higher than the temperature applied in the HTL process such that a DT (temperature difference) is maintained within the range 10 to 50° C.
  • the wet oxidation process provides more than 60% COD removal within 10 minutes.
  • the wet oxidation process provides more than 50% of the energy requirement for top heating the feed stream in the HTL process from the feed-in temperature to the process temperature.
  • top heating may refer to the extra heating to reach process temperature. It may also be referred to as “trim heating”, a term well-known for the person skilled in the art.
  • HTL conversion is conducted with recirculation to the feed stream of some portion of product aqueous phase.
  • the aqueous product phase subject to wet oxidation has COD levels within the range 60 to 120 g/L.
  • the HTL product stream which is filtered under pressure at temperature within the range 200 to 425° C so as to separate precipitates and which is subsequently separated into an aqueous product stream and an oil product stream.
  • the system according to the invention or any of its embodiments is adapted to operate in accordance with the method according to the invention or any of its embodiments.
  • the method of the invention or any of its embodiment is operated using the system of the invention or any of its embodiments.
  • Figure 1 shows a schematic illustration of an HTL system according to an embodiment of the invention with HTL and wet oxidation reactors integrated, co- or counter-current.
  • Figure 2 shows a process flow scheme for an HTL system integrated with wet oxidation in a heat exchange system.
  • Figure 3 shows one embodiment of integration of HTL and wet oxidation reactors by arrangement co- or counter-current within a heat exchange system.
  • Figure 4 shows another embodiment of integration of HTL and wet oxidation reactors by arrangement co- or counter-current within a heat exchange system.
  • Figure 5 shows a manifold which distributes HTL and wet oxidation feed streams to an integrated arrangement in a heat exchange system.
  • FIG. 6 shows one embodiment of an HTL system of the invention with external wet oxidation system and heat transfer loop. Detailed description of embodiments.
  • both the HTL process and the wet oxidation process can advantageously be conducted in direct thermal contact.
  • HTL process temperatures within the range 300 to 425° C wet oxidation proceeds very quickly.
  • resulting heat transfer to the HTL process can provide the heat required for top heating the HTL feed stream to process temperature within a few minutes.
  • the dielectric properties of water are dramatically altered. A significant consequence is that divalent and trivalent salts, and even some monovalent salts, become insoluble and precipitate.
  • the invention provides a hydrothermal liquefaction (HTL) system comprising: an inlet unit for aqueous slurries of biomass, a high pressure pumping system providing an outlet pressure of at least 100 bar in communication with the inlet unit, a continuous HTL reactor adapted to process biomass feedstocks at temperature within the range 300 to 425° C so as to produce an HTL product stream, an HTL heat exchanger, adapted to transfer heat from the HTL product stream to the HTL feed stream, a solid-liquid separation system adapted to operate under pressure at temperature within the range 200 to 425° C so as to separate solids from the HTL product stream, a separator adapted to recover a separate aqueous phase from the solid-liquid separated HTL product stream, a continuous wet oxidation reactor adapted to process at temperature within the range 300 to 425° C the aqueous phase obtained from the solid-liquid separated HTL product stream, and a wet oxidation heat exchanger adapted to transfer heat from the wet oxidation
  • HTL
  • the HTL heat exchanger and the wet oxidation heat exchanger are combined into one unit. In some embodiments, the HTL heat exchanger and the wet oxidation heat exchanger are separate units. In some embodiments, the HTL reactor and the wet oxidation reactor are combined into one unit. In some embodiments, the HTL reactor and the wet oxidation reactor are separate units.
  • the invention provides a method of hydrothermal liquefaction (HTL) comprising the steps of: providing an HTL biomass feed stream, conducting continuous HTL conversion of the HTL feed stream at temperature within the range 300 to 425° C in such manner as to produce an HTL product stream which is separated/filtered under pressure at temperature within the range 200 to 425° C so as to separate precipitates and which is subsequently separated into an aqueous product stream and an oil product stream, and conducting concurrent continuous or semi-continuous wet oxidation at temperature within the range 300 to 425° C of all or some portion of the HTL aqueous product stream, wherein heat produced by the wet oxidation process is used to heat the HTL feed stream.
  • HTL hydrothermal liquefaction
  • Biomasses suitable for use with the systems and methods of the invention typically include aqueous slurries of sewage sludge, energy grasses, wood chips, cereal straws, corn stover, other lignocellulosic agricultural and forestry wastes, seaweeds, algae, plankton, and other feedstocks.
  • HTL processes are typically conducted at the outer limit of pumpability of the slurry.
  • slurries as high as 15-20 wt. % dry matter (DM) content can typically be used, sometimes even as high as 35%.
  • lignocellulosic substrates slurries are typically within the range 14-18 wt. % DM.
  • the inlet unit for an HTL system of the invention is in fluid communication with a stirred feed buffer tank.
  • the high pressure pumping system for the HTL feed stream in an HTL system of the invention comprises high pressure pumps, which may include one or more positive displacement pumps such as piston pumps, membrane pumps, gear pumps, lobe pumps or hydraulic driven pumps, in which a pump chamber changes volume due to the admission of a hydraulic fluid.
  • the high pressure pumping system may preferably be arranged to provide a pressure high enough to keep the water stream in liquid state, e.g. a pressure of at least 100 bar, depending on the specific process conditions applied.
  • an HTL system of the invention further comprises a high pressure pumping system for the wet oxidation feed stream.
  • Continuous HTL conversion is typically conducted using a system that pumps biomass slurry into a tubular reactor at process pressure, which is typically well over 100 bar.
  • the temperature of the feed stream typically is increased during the conversion process from an initial feed-in temperature that can be achieved through use of heat exchangers that recover heat from the product stream to the steady-state process temperature.
  • the HTL product stream prior to its removal from the pressurized HTL reactor, is separated/filtered at process temperature within the range 300 to 425° C, or in some embodiments, after slight cooling at a temperature within the range 200 to 425° C.
  • Any suitable solid-liquid separation system may be used for this purpose, including but not limited to filtration system, such as the system described in US9,404,063, or hydrocyclones, or centrifuges.
  • the HTL conversion process is conducted at a temperature within the range 300 to 425° and at a pressure within the range 85 to 300 bar.
  • Residence time within the HTL reactor is typically controlled by the rate of pumping feed stream into and removal of product out from the reactor. Residence time is thus ultimately limited by the length and internal volume of the reactor, in the case of a tubular reactor.
  • flow within the reactor can be oscillatory such that the feed stream moves back and forth within the reactor as it is gradually transported towards the output end. Removal of product stream from the reactor is typically achieved using a de-pressurization system that conserves process heat as much as possible.
  • Suitable pumping systems include a variety of systems known in the art, including but not limited to any of the combined pumping and depressurization systems described in W02016/004958 which is hereby incorporated by reference in entirety.
  • HTL conversion is conducted according to the method described in Anastasakis (2016) with the additional feature of separation/filtration of the HTL product stream under pressure at process conditions.
  • the HTL product steam is passed through a heat exchange system that simultaneously heats the incoming feed stream and cools the product stream.
  • the cooled HTL product stream after heat exchange is separated into aqueous, oil and gaseous phases.
  • a three phase separator is applied to the HTL product stream after heat exchange.
  • continuous HTL conversion is conducted with recirculation to the feed stream of some portion of product oil or aqueous phase product or both.
  • the COD levels obtained in the aqueous product phase differ depending on the extent to which aqueous phase has been recirculated. Even in single-pass configurations, where the biomass feed stream has 15 to 20 wt. % dry matter content, COD content of the aqueous product stream typically has between 20 to 50 g/L COD. In processes where some portion of the aqueous product stream is recycled, aqueous COD levels typically fall within the range 60 to 120 g/L.
  • all or part of the HTL aqueous product stream is subject to continuous wet oxidation at temperature within the range 300 to 425° C and heat produced by the wet oxidation process is used to heat the HTL feed stream.
  • the wet oxidation processes a feed stream of aqueous separated/filtered HTL product to a product stream of comparatively purified wastewater which can typically be readily consumed in anaerobic digestion.
  • the wet oxidation process may use in situ oxygen generation to supplement or replace compressed air.
  • the high pressure gas injector is a gas sparger providing good contact between the aqueous and gas phase.
  • applied oxygen pressure is within the range 100 to 300 bar, or 150 to 250 bar, or 60 to 200 bar.
  • COD levels of the aqueous product stream subject to wet oxidation is between 20 and 120 g/L, or between 23 and 70 g/L.
  • the oxygen concentration in the injected gas stream is between 15% and 100% as a wt.% of the gas phase, or between 20-50%, or between 60-100%.
  • oxygen can be generated using comparatively inexpensive systems such as membrane-based concentrators, or, alternatively via more costly systems that provide additional advantages, such as an alkaline electrolyzer or a solid oxide electrolysis cell.
  • Electrolysis will provide both oxygen and a valuable side stream of hydrogen that can be utilized for various processes such as hydrotreatment of the product biocrude oil.
  • electrolytically generated oxygen will ideally be compressed to around 200 bar before injecting into the wet oxidizer, which can provide a desired preheating of the produced oxygen.
  • the addition of air or an oxygen rich gas stream is performed using one or several injection points, such as gas spargers, to ensure the necessary amount of oxygen available for the reaction.
  • the injection points may be located near the entry of the wet oxidation reactor or distributed over the length of said reactor.
  • two or more wet oxidation reactors placed in the system in a parallel or serial manner.
  • the addition of air or an oxygen rich gas stream is performed in a manner where the said gas flow is controlled via a feedback loop (control system) to ensure a desired conversion rate and production of heat.
  • This control system may also provide a means for avoiding overheating of the wet oxidation reactor.
  • the feedback loop may be controlled by one or more sensors measuring temperature, pressure, or chemical characteristics of the reaction medium.
  • heat produced by the wet oxidation process is used to heat the HTL feed stream by integrating a separate HTL reactor and a wet oxidation reactor in a co- or counter-current arrangement whereby the reactors are in direct thermal contact via a heat exchange system.
  • this integration is achieved where both the HTL reactor and the wet oxidation reactor are tubular, or otherwise designed to provide some degree of tubular flow. Tubular reactors are typically the most technically simple and least costly available option.
  • the wet oxidation process can advantageously provide sufficient excess heat to increase the temperature of the HTL feed stream from the feed-in temperature achieved by heat exchangers to the steady state process temperature.
  • the wet oxidation process is conducted at a temperature higher than the temperature applied in the HTL process such that a DT (temperature difference) is maintained to drive heat transfer.
  • DT between the wet oxidation process and the HTL process is within the range 10 to 50° C, or between 15 and 70° C. At temperature within the range 300 to 425° C, wet oxidation can typically be conducted so as to provide more than 60% COD removal within 10 minutes.
  • the wet oxidation process achieves COD removal within 10 minutes, or within 15 minutes, or within 20 minutes between 50 and 99% or between 40 and 80% or between 60 and 85%.
  • an appropriate set of wet oxidation conditions such that the residence time for wet oxidation can be within 20 minutes, or within 15 minutes, or within 10 minutes, so that heat transfer to the HTL process can provide the required top heating quickly.
  • tubular wet oxidation and HTL reactors are integrated within a heat exchange system such that direct thermal contact is maintained for sufficient time to provide heat transfer for top heating the HTL feed stream followed by one or more continuing sections of HTL reactor which is not integrated with the wet oxidation reactor.
  • the wet oxidation and HTL reactors can typically have similar dimensions.
  • the wet oxidation reactor is arranged as a tube within a tube heat exchanger with the HTL reactor residing in the central tube and the wet oxidation reactor residing in the outer tube shell. This arrangement of the reactors is feasible since the aqueous HTL wastewater typically contains no particulate material and is thus less prone to clog the layer between the inner and outer tube. In such a setup the wall thickness of the inner tube may be reduced to improve heat transfer as the outer tube wall will carry the main part of the pressure load.
  • the residence time for the wet oxidation process is longer than the residence time for the HTL process.
  • the residence time for the HTL process is longer than the residence time for the HTL process.
  • residence time in the wet oxidation process is between 5 and 30 minutes, or between 2 and 10 minutes, or between 3 and 15 minutes, or between 5 and 20 minutes, or between 12 and 60 minutes, or between 1 and 8 minutes. In some embodiments, residence time in the HTL process is between 5 and 120 minutes, or between 10 and 60 minutes, or between 12 and 40 minutes, or between 7 and 100 minutes. In some embodiments, the wet oxidation process is conducted at a temperature between 300 and 375° C, or between 330 and 425° C. In some embodiments, the HTL process is conducted at a temperature between 300 and 375° C, or between 330 and 425° C. In some embodiments, the wet oxidation process provides more than 50% of the energy requirement for top heating the feed stream in the HTL process from the feed-in temperature to the process temperature, or more than 60%, or more than 80%.
  • the HTL and wet oxidation reactors can ideally ensure a residence time of at least 300 seconds (5 minutes) up to 120 minutes.
  • the diameter of the reactors is typically optimized to ensure good thermal transfer and typical dimensions are between 15 mm and 100 mm and the length between 5-500 m or between 10 m and 500 m or between 50 m and 500 m.
  • the flowrate applied in an HTL process conducted in a tubular reactor is suitably in the range of 0.05 and 2 m/s.
  • FIG. 1 describes one non-limiting example of methods and systems of the invention, any feature of which may be used in an HTL system or method of the invention in combination with any other system or feature described here or otherwise known in the art.
  • a biomass feed stream is combined with some portion of aqueous phase HTL product in a feed mixer (A).
  • the mixed feedstock and recycled aqueous phase slurry is pre-heated by being fed through a high pressure feed pump (B) such as, for example, any of the pump systems described in W02016/004958 into an HTL heat exchanger (C).
  • B high pressure feed pump
  • C HTL heat exchanger
  • the pre-heated feed stream is further pumped into the HTL component of an integrated reactor system (D) having separate HTL and wet oxidation reactors arranged co- or counter-current in direct thermal contact enhanced in some embodiments by heat exchangers such as any of those described in WO2021/024176, which is hereby expressly incorporated by reference in entirety.
  • the output from the HTL component of an integrated HTL and wet oxidation reactor system (D) is fed through an online solid liquid separation system 0), such as a filtration system Q), which is adapted to separate solids including precipitated salts from the product stream under pressure at the HTL process temperature.
  • Solids recovered from J are periodically blown through a valve to a blow down tank K.
  • the separated/filtered HTL product stream is then fed through an HTL heat exchanger (C) to contribute to pre-heating of the HTL input feed stream, then released through a valve into a three phase separator (E) that separates a gaseous product phase, a product oil phase and an aqueous product phase. Some portion of the aqueous product phase separated by a three phase separator (E) is recycled to the HTL process by mixing with incoming feedstock in a feed mixer (A).
  • aqueous product phase separated by a three phase separator is pumped through a water phase feed pump (F) through a wet oxidation heat exchanger (G) to pre-heat the wet oxidation wastewater stream prior to its being aerated/oxygenated by an air/oxygen sparger (H).
  • the pre-heated, aerated/oxygenated wastewater stream is further pumped into the wet oxidation component of an integrated reactor system (D) having separate HTL and wet oxidation reactors arranged co- or counter-current in direct thermal contact.
  • the output from the wet oxidation component of an integrated HTL and wet oxidation reactor system (D) is fed through the wet oxidation heat exchanger (G) to pre-heat the wastewater stream prior to wet oxidation, then released through a valve into a water/gas separator (I) that separates a gaseous phase and a comparatively purified water phase.
  • Table 1 This shows results of batch wet oxidations experiments which are explained in detail in example 1 conducted with HTL aqueous product.
  • the underlying HTL process from which the aqueous samples were derived was conversion of dewatered sewage sludge at 16 wt.
  • % DM at a temperature of 325° C for a residence time of approximately 60 minutes in a one-pass process without recirculation of aqueous phase.
  • the HTL aqueous product had COD content 28.3 g/L, which is typical of levels achieved in a one pass HTL process.
  • COD removal efficiency achieved by the wet oxidation process is shown as the mean of two replicate experiments for retention times between 2 and 10 minutes at oxygen initial pressure loading 90 bar for temperatures between 300 and 350° C. Also shown for each set of process conditions is the estimated energy released from the wet oxidation process in kJ/L, based on a yield of 435 kj per mole of 02 reacted. As shown, at 350° C, which is a typical HTL process temperature, and 90 bar initial oxygen pressure loading, 73% COD removal is achieved within 10 minutes.
  • the heat required for top heating the HTL feed stream to process temperature is described in Table 2. Inputs for the table are based on results from the Aarhus University HTL pilot plant and an assumption that the wet oxidation heat exchanger can be operated with high efficiency of 95%. Aqueous product mass is estimated to be 0.85 that of the feed stream slurry.
  • the results in Table 2 refer to the process flow scheme shown in Figure 2. As shown in Figure 2, the initial feed stream is flow A to the HTL heat exchanger. Flow B is the feed- in to the integrated HTL/wet oxidation reactor. Flow C is the HTL product stream to the pressurized solid-liquid separation system, such as filtration system. Flow D is the separated/filtered HTL product stream to the HTL heat exchanger.
  • Flow E is the cooled, separated/filtered HTL product stream to a three phase separator.
  • Flow F is the aqueous product stream to the wet oxidation heat exchanger.
  • Flow G is the wet oxidation feed-in to the integrated HTL/wet oxidation reactor.
  • Flow H is the wet oxidation output stream to the wet oxidation heat exchanger.
  • Flow I is the cooled wet oxidation output stream.
  • Table 2 shows the expected temperature and corresponding energy content for pure water in integrated HTL/wet oxidation processes at 325 and 350 °C with DT for the wet oxidation process of 25 and 20° C respectively.
  • An actual biomass slurry has considerably less heat capacity than pure water.
  • the percentage of HTL energy requirement for a process at 350° C which can be provided by 10 minutes wet oxidation of aqueous product is shown in Table 3.
  • the % COD removal efficiency from Table 1 for 28.3 g/L COD at 350° C is extrapolated to higher levels of COD associated with an HTL process where aqueous product is recirculated.
  • the resulting energy release is expressed as a percentage of the energy requirement shown in Table 2.
  • Table 2 Energy requirement for HTL process.
  • Table 3 Percentage of HTL energy requirement at 350° C provided by 10 minutes wet oxidation of aqueous product.
  • heat produced by the wet oxidation process is used to heat the HTL feed stream by conducting wet oxidation in a separate, external unit.
  • excess heat can then be provided to the HTL process via a fluid heat transfer medium such as high pressure steam, high pressure compressed water, hot oil or molten salt.
  • the product stream from the separate wet oxidation unit can further be used in an additional heat exchanger to preheat the wet oxidation feedstock stream to, for example, 250° C.
  • the dimensions of the wet oxidation reactor can be independent of the HTL reactor dimensions.
  • the wet oxidation reactor can be a fed- batch system.
  • FIG 3 describes one non-limiting example of integration of tubular wet oxidation and HTL reactors by an arrangement co- or counter-current in direct thermal contact via a heat exchange system. Shown is the heat exchange system for a tubular HTL reactor described in Figure 3 of WO2021/024176.
  • the HTL feed stream is divided into tubular reactor sections (1) each of which is surrounded by heat transfer clamps (2) made from a solid matrix of heat conducting material.
  • the individual heat transfer clamps (2) comprise support formations that position and support the tubular reactor sections.
  • the tubular sections (1) can be arranged in different ways. For example, three sections corresponding to equivalent residence times can be aligned co- or counter current within the heat exchange system with three sections corresponding to later residence times.
  • the wet oxidation stream and the HTL stream are divided into sections aligned co- or counter within the heat exchange system such that a tubular section of the HTL reactor (3) is always adjacent to a tubular section of the wet oxidation reactor (4).
  • Figure 4 describes another non-limiting example of integration of tubular wet oxidation and HTL reactors by an arrangement co- or counter-current in direct thermal contact via a heat exchange system. Shown is the heat exchange system for a tubular HTL reactor described in Figure 6a of WO2021/024176. As with the system shown in Figure 3, Figure 4 shows tubular reactor sections (6) surrounded by heat transfer clamps (5) made from a solid matrix of heat conducting material where each individual heat transfer clamp comprises support formations that position and support the tubular reactor. In this case the geometry of the heat clamps provides a circular array.
  • the wet oxidation stream and the HTL stream are divided into different sections aligned co- or counter within the heat exchange system such that a tubular section of the wet oxidation reactor (7) is always adjacent to a tubular section of the HTL reactor (8).
  • FIG 5 shows one non-limiting example of how the HTL feed stream can be fed to the combined HTL and wet-oxidation reactor/heat exchanger shown in Figure 4.
  • the relatively high viscosity preheated biomass suspension is distributed via the inlet connector (9) into the HTL reactor tube sections (14) via the distributor block/manifold (12). Viscous biomass slurries are advantageously pumped in an unrestricted direct flow path with minimized curvatures.
  • the low viscosity preheated and oxygenated wet oxidation wastewater is easier to handle and can be fed to the side inlet (10) and distributed to the wet oxidation reactor tube sections (13) via the circular distributor channel (11).
  • the wet oxidation feed stream may be fed co- or counter-current to the direction of the HTL flow.
  • FIG. 6 describes another non-limiting example of methods and systems of the invention, any feature of which may be used in an HTL system or method of the invention in combination with any other system or feature described here or otherwise known in the art.
  • a biomass feed stream is combined with some portion of aqueous phase HTL product in a feed mixer (A).
  • the mixed feedstock and recycled aqueous phase slurry are pre heated by being fed through a high pressure feed pump (B) such as, for example, any of the pump systems described in WO2016/004958, into an HTL heat exchanger (C).
  • the pre heated feed stream is further heated by being pumped into a co-current heat exchanger with molten salt (D).
  • the input feed heated to process temperature is further pumped into an HTL reactor (E).
  • Output of product from the HTL reactor (E) is fed through an online solid- liquid separation system (N), such as an online filtration system (N), which is adapted to separate solids including precipitated salts from the product stream under pressure at the HTL process temperature. Solids recovered from N are periodically blown through a valve to a blow down tank O.
  • the separated/filtered HTL product stream is then fed through an HTL heat exchanger (C) to contribute to pre-heating of the HTL input feed stream, then released through a valve into a three phase separator (F) that separates a gaseous product phase, a product oil phase and an aqueous product phase.
  • Some portion of the aqueous product phase separated by a three-phase separator (F) is recycled to the HTL process by mixing with incoming feedstock in a feed mixer (A).
  • Some portion of the aqueous product phase separated by a three phase separator (F) is pumped through a water phase feed pump (G) through a wet oxidation heat exchanger (H) to pre-heat the wastewater stream prior to its being aerated/oxygenated by an air/oxygen sparger (I).
  • the pre-heated, aerated/oxygenated wastewater stream is further pumped into a wet oxidation reactor with molten salt cooling (J).
  • the molten salt cooling system for wet oxidation reactor (J) comprises a molten salt buffer tank (K) from which molten salt is pumped by molten salt pump (L) to a co-current heat exchanger with molten salt (D) to transfer heat from molten salt cooling to the HTL input stream.
  • the output from the wet oxidation reactor with molten salt cooling (J) is fed through the wet oxidation heat exchanger (H) to pre-heat the wastewater stream prior to wet oxidation, then released through a valve into a water/gas separator (M) that separates a gaseous phase and a comparatively purified water phase.
  • Hydrothermal liquefaction of dewatered sewage sludge was performed on the continuous HTL pilot-plant at Aarhus University as described in detail by Anastasakis (2016).
  • HTL process conditions were 325° C, 43 L/hour, feed stream 16 wt. % DM content, residence time approximately 60 minutes.
  • the HTL product was separated into an aqueous phase (AP) and an oil phase.
  • the aqueous product was not recirculated such that the COD level of the resulting AP corresponds to values associated with a “one pass” process.
  • Wet oxidation of HTL-AP was carried out in custom built Hy-Lok reactors.
  • the reactors were constructed from 316 stainless steel 3 ⁇ 4 inch Hy-lok pipes.
  • each reactor had a total internal volume of 20 mL - 3 ⁇ 4 inch pipe with 10 cm in length.
  • the pressurized reactors were submerged into a pre-heated fluidized sand bath and continuously mixed in a shaker. Experiments was performed at two different temperatures (300, and 350°C) and two retention times (2 and 10 minutes). After the reaction time, the reactors were cooled to room temperature and the samples were collected and stored at 2°C.
  • HTL-AP samples and the samples after wet oxidation were analyzed for chemical oxygen demand (COD) and ammonium (NH 4 + ) content using Merck Spectroquant cell tests (part numbers: COD-114541 and NH4+-114559).
  • the initial HTL-AP material had COD content 28.3 g/L.
  • the energy release (ER) was calculated based on the difference between the initial and final concentration of COD (mol) and the general material balance for wet oxidation process, where the heat value is estimated to be approximately 435 kj per mole of 02 reacted, as reported by Debellefontaine (2000).
  • Table 1 shows results of the experiments. Shown are the average +/- standard deviation of COD removal % and energy release. As shown, at process temperature 350°C, 73% COD removal can be achieved by the wet oxidation process within 10

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Abstract

L'invention concerne un système de liquéfaction hydrothermal (HTL), le système HTL comprenant : une unité d'entrée pour les boues aqueuses de biomasse, un système de pompage à haute pression fournissant une pression de sortie d'au moins 100 bars en communication avec l'unité d'entrée, un réacteur HTL continu adapté pour traiter les matières premières de biomasse à une température comprise entre 300 et 425 °C de manière à produire un flux de produit HTL, un échangeur de chaleur HTL, conçu pour transférer la chaleur du flux de produit HTL au flux d'alimentation HTL, un système de filtration ; un système de séparation solide-liquide conçu pour fonctionner sous pression à une température comprise entre 200 et 425 °C de manière à séparer les solides du flux de produit HTL, un séparateur conçu pour récupérer une phase aqueuse séparée à partir du flux de produit HTL filtré et à solide-liquide séparé, un réacteur d'oxydation humide continu conçu pour traiter, à une température comprise entre 300 et 425 °C, la phase aqueuse obtenue à partir du flux de produit HTL filtré et à solide-liquide séparé, et un échangeur de chaleur d'oxydation humide conçu pour transférer la chaleur du flux de produit d'oxydation humide au flux d'alimentation d'oxydation humide, le réacteur HTL et le réacteur d'oxydation humide étant intégrés par un agencement à cocourant ou à contre-courant en contact thermique direct par le biais d'un système d'échange de chaleur. L'invention concerne également un système de liquéfaction hydrothermal (HTL) et un procédé de liquéfaction hydrothermal (HTL).
EP21743373.9A 2021-06-23 2021-06-23 Intégration rentable de liquéfaction hydrothermale et de traitement des eaux usées par oxydation humide Pending EP4359352A1 (fr)

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JPH04344137A (ja) 1991-05-20 1992-11-30 Sanyo Electric Co Ltd 電動機の固定子及び固定子の製造方法
JP2002308688A (ja) * 2001-04-09 2002-10-23 Ishikawajima Harima Heavy Ind Co Ltd 有機廃棄物を原料とした肥料の製造方法及びその装置
US9404063B2 (en) 2013-11-06 2016-08-02 Battelle Memorial Institute System and process for efficient separation of biocrudes and water in a hydrothermal liquefaction system
WO2016004958A1 (fr) 2014-07-11 2016-01-14 Aarhus Universitet Procédé et appareil de production de biocarburant au sein d'une chaîne de production à écoulement oscillatoire et sous des conditions fluidiques supercritiques
FR3030562B1 (fr) * 2014-12-19 2018-08-24 Commissariat A L'energie Atomique Et Aux Energies Alternatives Procede ameliore de conversion de biomasse algale en un gaz ou en bio-crude respectivement par gazeification ou liquefaction hydrothermale
FR3035404B1 (fr) 2015-04-22 2019-04-05 Commissariat A L'energie Atomique Et Aux Energies Alternatives Dispositif et procede de traitement de la biomasse
GB2586145A (en) 2019-08-07 2021-02-10 Ibj Tech Ivs Improvements in or relating to heat exchangers

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