Organic waste treatment method

Abstract

The invention relates to a hydrothermal treatment method for treating a mixture M1 comprising at least organic substances, said method comprising: a) pressurizing the mixture M1 comprising at least organic substances to obtain a mixture stream M1p, b) injecting water at a temperature of at least 374 DEG C into the mixture stream M1p at an angle of 15 DEG C to 90 DEG C to obtain a mixture stream M2 comprising water and organic substances, c) introducing the mixture stream M2 into a hydrothermal treatment reactor, said hydrothermal treatment reactor being maintained at a temperature of 150 DEG C to 430 DEG C, to obtain a mixture stream M3 comprising the hydrothermally treated organic matter.

Description

Technical Field

[0001] The present invention relates to the field of biomass treatment, in particular the treatment of sludge from sewage treatment plants, food and agro-food waste, faecal digestate and agricultural residues. Background Art

[0002] Hydrothermal treatments of biomass are increasingly being used. They require high temperature conditions. Therefore, controlling the temperature is crucial in order to obtain the desired quality of the hydrothermal treatment of biomass.

[0003] Therefore, controlling the temperature and residence time of the process is extremely important to obtain the desired results. Too high or too low a temperature, too short or too long a residence time either results in the desired reaction not occurring, or results in undesirable side reactions, resulting in an overall deterioration of the desired performance, or even in the production of residues that are more expensive to handle.

[0004] In particular, in hydrothermal treatments, the heating step is the main cause of initiating these side reactions, due to the longer residence time at the intermediate temperature, which can lead to the formation of undesirable compounds such as oil, tar or derivatives close to coal. The higher the temperature to be reached, the longer the heating step, in particular when the temperature to be reached is close to or above the temperature of supercritical water.

[0005] Furthermore, in the prior art, heating is usually carried out by a "tube-in-tube" type heat exchanger to recover the heat of the stream or product discharged from the hydrothermal treatment reactor, thereby reducing the heat required for the process. However, in this type of heat exchanger, the thermal conductivity of the product to be heated is poor, resulting in very large temperature variations inside the product and, therefore, inconsistent process conditions between different parts of the product, which in turn leads to undesirable side reactions.

[0006] Therefore, there is a need to provide a method for the hydrothermal treatment of biomass type mixtures in order to achieve better heat exchange effects and reduce the formation of undesirable compounds such as oils, tars or near coal derivatives. Summary of the invention

[0007] The present invention relates to a hydrothermal treatment method for treating a mixture M1 containing at least organic matter, comprising:

[0008] a) pressurizing a mixture M1 comprising at least an organic substance to obtain a mixture flow M1p,

[0009] b) injecting water having a temperature of at least 374° C. into the mixed flow M1p at an angle of 15° to 90° to obtain a mixed flow M2 comprising water and organic matter,

[0010] c) introducing the mixed stream M2 into a hydrothermal treatment reactor maintained at a temperature ranging from 150° C. to 430° C., so as to obtain a mixed stream M3 comprising hydrothermally treated organic matter.

[0011] According to one embodiment, the pressure of the water injected in step b) is at least 225 bar, so the method optionally comprises a step of pressurizing the water to at least 225 bar.

[0012] According to one embodiment, the mixed flow M2 is introduced into a static turbulator, preferably selected from a propeller, a blade, one or more pipe elbows or a combination thereof, before being introduced into the hydrothermal treatment reactor.

[0013] According to one embodiment, the method further comprises:

[0014] at least one heat exchange step X1 for recovering heat from the mixed stream M3 in order to at least partially heat the water to be injected in step b) so as to obtain a cooled mixed stream M3', and optionally comprising at least one additional water heating step downstream of the heat exchange step X1 so as to heat the water to a temperature of at least 374°C before injecting it in step b), and

[0015] - optionally at least one heat exchange step X2 for recovering heat from the mixed stream M3' in order to heat the mixture M1p before the injection of water in step b) so as to obtain a cooled mixed stream M3".

[0016] According to one embodiment, the method further comprises:

[0017] at least one cooling step of cooling at least a portion of the mixed stream M3′ or, where appropriate, at least a portion of the mixed stream M3″ to obtain steam and a mixed stream M4 comprising the hydrothermally treated organic matter, and

[0018] - a steam injection step of injecting at least a portion of said steam in order to preheat the mixture M1 upstream of the pressurization step a).

[0019] According to one embodiment, the mixture M1 is preheated upstream of the pressurization step a) to a temperature ranging from 50 to 160°C, preferably from 50 to 90°C.

[0020] Preferably, at least a portion of the mixed flow M3' or, where appropriate, at least a portion of the mixed flow M3" is cooled at a pressure adjusted as a function of the preheating temperature of the mixture M1 upstream of the pressurization step a).

[0021] According to one embodiment, the method further comprises a cooling step of cooling at least a portion of the mixed stream M4 to obtain a mixed stream M4', and subjecting at least a portion of the mixed stream M4' to at least one digestion step.

[0022] According to one embodiment, when injecting water in step b), the temperature of the mixture M1p is between 90°C and 300°C, preferably between 90°C and 170°C.

[0023] According to one embodiment, the method further comprises the step of injecting water at a temperature of at least 374°C directly into the hydrothermal treatment reactor, said water preferably having the same temperature and pressure as the water injected in step b).

[0024] Preferably, the mixed stream M3 comprising the hydrothermally treated organic matter is recovered through an outlet at the upper part of the reactor, the reactor further comprising an outlet at the lower part of the reactor.

[0025] Preferably, the mixed stream M3 comprising the hydrothermally treated organic substances leaving the reactor can be subjected to one or more further subsequent treatment steps, if appropriate carried out upstream of the heat exchanges X1 and X2 .

[0026] Another subject of the invention is a device for implementing the hydrothermal treatment method according to the invention, comprising:

[0027] - a feed line for the mixture M1,

[0028] a pressure pump 2 supplied by the feed line of the mixture M1 and comprising an outlet line of the mixture M1p,

[0029] - a device for injecting water ES, for injecting water ES into the line of mixture M1p downstream of the booster pump 2 at an angle of 15° to 90°,

[0030] a feed line for the mixed stream M2, downstream of the means for injection of water ES and upstream of the hydrothermal treatment reactor,

[0031] A hydrothermal treatment reactor 1 comprising at least one inlet for introducing at least a portion of the mixed flow M2 and at least one outlet for withdrawing the mixed flow M3.

[0032] According to one embodiment, the device according to the present invention further comprises:

[0033] - a static turbulator 10 , fed with the mixed flow M2 , said static turbulator being located upstream or at the inlet of the hydrothermal treatment reactor 1 , and

[0034] a heat exchanger 6 situated downstream of the hydrothermal treatment reactor 1, capable of recovering the heat of the mixed flow M3 to obtain a mixed flow M3' and transferring this heat to the water upstream of the means for injection of the water ES, and

[0035] - Optional water heating means 7, situated downstream of the heat exchanger 6 and upstream of the means for injection of water ES.

[0036] According to one embodiment, the device according to the present invention further comprises:

[0037] an optional heat exchanger 8 capable of recovering heat from the mixture M3' to obtain a mixture M3", and transferring this heat to the mixture M1p upstream of the water ES injection device,

[0038] a cooling device 4 supplied with at least a portion of the mixed flow M3' or, where appropriate, the mixture M3", making it possible to produce steam and a cooling flow M4,

[0039] - a steam injection device 3 for injecting the generated steam into the mixed flow M1 upstream of the booster pump 2,

[0040] an optional cooling device 9, located downstream of the cooling device 4 and supplied with at least a portion of the mixed flow M4, for cooling at least a portion of the mixed flow M4 to obtain a mixed flow M4', and

[0041] - An optional digester 5, which is fed by the mixture stream M4'.

[0042] Therefore, the present invention can rapidly heat the biomass by direct heating, thereby accurately controlling subsequent target process conditions.

[0043] In addition, the present invention can also achieve uniform heating of the biomass through the static mixer, which also enables precise control of target process conditions.

[0044] Finally, the present invention maintains heat recovery in the process by heating the water under supercritical conditions, thereby minimizing the overall heat consumption of the process.

[0045] Biomass has a certain viscosity. However, viscosity makes heat exchange difficult. Since the viscosity of water is lower than that of any biomass, heating water can achieve a smaller recovery exchanger, thus reducing costs.

[0046] The present invention proposes to inject supercritical water directly into the organic material flow M1. Therefore, the thermal shock between the organic material (M1), a part of which is cell contents, and the supercritical water at a very high temperature will cause a difference in local density, thereby generating a difference in local pressure, triggering local cavitation phenomena. These cavitation phenomena cause the cell contents to be immediately released into the aqueous matrix, thereby immediately triggering the reaction of proteins and sugars in the bacteria in the hydrothermal reactor.

[0047] BRIEF DESCRIPTION OF THE DRAWINGS

[0048] [ Figure 1 ] represents an apparatus according to an embodiment of the method of the present invention.

[0049] [ Figure 2 ] represents an apparatus according to an embodiment of the method of the present invention.

[0050] [ Figure 3 ] represents an apparatus according to an embodiment of the method of the present invention.

[0051] [ Figure 4 ] represents an apparatus according to an embodiment of the method of the present invention.

[0052] [ Figure 5 ] represents an apparatus according to an embodiment of the method of the present invention.

[0053] [ Figure 6 ] represents an apparatus according to an embodiment of the method of the present invention.

[0054] Detailed Description of the Invention

[0055] The invention relates to the hydrothermal treatment of a mixture M1 comprising organic matter. The mixture M1 also comprises inorganic matter.

[0056] The mixture M1 is typically biomass. The biomass may be pasty or liquid, in particular sludge from sewage treatment plants, food and agro-food waste, in particular fecal digestate and agricultural residues.

[0057] The present invention relates to a hydrothermal treatment method for treating a mixture M1 containing at least organic matter, comprising:

[0058] a) pressurizing a mixture M1 comprising at least an organic substance to obtain a mixture flow M1p,

[0059] b) injecting water having a temperature of at least 374° C. into the mixed flow M1p at an angle of 15° to 90° to obtain a mixed flow M2 comprising water and organic matter,

[0060] c) introducing the mixed stream M2 into a hydrothermal treatment reactor maintained at a temperature ranging from 150° C. to 430° C., so as to obtain a mixed stream M3 comprising hydrothermally treated organic matter.

[0061] Within the meaning of the present invention, the expression "at least a part of a mixture or a mixed flow" has the same meaning as the expression "all or a part of said mixture or mixed flow". When referring to said mixture or a part of said mixed flow, the expression refers to a certain proportion of said mixture or said mixed flow. For example, "every part of a mixture" or "every part of a mixed flow" will have the same composition in the sense of this expression.

[0062] Within the meaning of the present invention, the expression "where appropriate in step X" introduces a feature that is present when step X is present.

[0063] Within the meaning of the present invention, the expression "where appropriate in the case of a mixture stream X" introduces features which are present when the mixture stream X is present.

[0064] Pressurization step a)

[0065] The method according to the invention comprises a pressurizing step of pressurizing the mixture M1 to a pressure preferably ranging from 150 to 350 bar, preferably from 170 to 220 bar, while said mixture M1 may already be in a pressurized state.

[0066] For the pressurization step, a pump can be provided on the mixture M1 line.

[0067] Downstream of the pressurization step, a mixed stream M1p is obtained.

[0068] Water injection step b)

[0069] The method according to the invention comprises a step in which water having a temperature of at least 374° C. is injected into the mixture stream M1p to obtain a mixture stream M2 comprising water and organic substances. The mixture M2 generally also comprises inorganic substances.

[0070] The injection of water is carried out at an angle inclined relative to the feed line of the mixed stream M1p, ranging from 15° to 90°, preferably from 45° to 90°, or even from 45° to 75°.

[0071] Figure 1 The angle defined in the present invention, ie the angle (α) between the injection line of the water ES and the arrival line of the mixed flow M1p is shown.

[0072] After the injection of water ES, the line of the mixed flow M2 may not be parallel to the line of the mixed flow M1p. For example, the line of the mixed flow M2 may include turbulators consisting of one or more changes of direction of the pipe before entering the hydrothermal treatment reactor.

[0073] According to one embodiment, during the injection of water in step b), the mixed stream M1p is at a temperature comprised between 90°C and 300°C, preferably between 90°C and 170°C.

[0074] The mixture M1p can be heated in one or more steps, for example by heat exchange and / or by external heating.

[0075] Upstream of step b), the water injected is generally at a pressure higher than the pressure of the mixture M1p.

[0076] According to a preferred embodiment of the present invention, the pressure of the water injected in step b) is at least 225 bar. According to this embodiment, the injected water is called "supercritical water".

[0077] According to one embodiment, the method of the invention comprises at least one step of heating the water, so as to heat the water to at least 374° C. before injecting in step b).

[0078] According to one embodiment, the method according to the invention comprises a step of pressurizing the water to a pressure of at least 225 bar, followed by at least one step of heating the water to at least 374° C. before injection in step b).

[0079] Preferably, at least one step of heating water is carried out by heat exchanging heat with at least a part of the mixed flow M3 containing the hydrothermally treated organic matter leaving the hydrothermal treatment reactor, whereby the cooled mixed flow will be called mixed flow M3' at the end of this heat exchange (which may be the heat exchange step X1 described below).

[0080] At the outlet of the injection between water and sludge M1p, static turbulators (e.g. selected from propellers, blades, pipe elbows or combinations thereof) may also be introduced to increase the turbulence between sludge and water and promote their rapid exchange and prevent sludge and water from remaining in separate flows (to avoid laminar water lines).

[0081] Therefore, according to one embodiment of the invention, upstream of step c), the mixture M2 is introduced into a static turbulator located just upstream or at the inlet of the hydrothermal treatment reactor.

[0082] According to one embodiment, static turbulators are located upstream or at the inlet of the hydrothermal treatment reactor to increase turbulence in the mixture M2.

[0083] Step c)

[0084] The method according to the invention comprises a step of introducing the mixed stream M2 into a hydrothermal treatment reactor, optionally after passing through a static turbulator.

[0085] The hydrothermal treatment reactor is advantageously maintained at a temperature between 150° C. and 430° C. Maintenance of temperature can be achieved, for example, by peripheral heat exchange with a hot fluid, by using the apparatus in a constant temperature furnace, by using electrical heating collars.

[0086] In the method of the present invention, the flow rate of the injected water (preferably supercritical water) and the mixed stream M1p is advantageously controlled, and the residence time of the new mixture (referred to as M2) in the hydrothermal treatment reactor is generally made to reach 1 minute to 30 minutes, preferably 10 minutes to 15 minutes. At the outlet of the hydrothermal treatment reactor, a mixed stream of organic matter containing hydrothermal treatment, i.e., mixed stream M3, is obtained. The method of the present invention generally includes the step of extracting stream M3.

[0087] Advantageously, the hydrothermal treatment reactor is provided with an outlet for the mixture M5, i.e. the so-called mixture not subjected to hydrothermal treatment. In practice, the hydrothermal treatment reactor can be equipped with a separation device, such as a filter, to obtain a mixture stream rich in soluble substances (mixture stream M3) and a mixture stream poor in soluble substances (mixture stream M5), and extract them from the reactor.

[0088] Within the meaning of the present invention, the term "mixed stream enriched in soluble substances" refers to a mixed stream which contains a higher weight proportion of soluble substances than in the mixture M2.

[0089] Within the meaning of the present invention, the term "mixed stream depleted in soluble substances" refers to a mixed stream containing soluble substances in a lower weight proportion than in the mixture M2.

[0090] Within the meaning of the present invention, soluble matter refers to the matter obtained after filtering through a 40 μm filter (material not retained by said 40 μm filter) and then drying the initial material. The filter may comprise one or more filter layers, each layer optionally having a different mesh size, preferably the mesh size of the outer filter layer being larger than the mesh size of the inner filter layer.

[0091] According to one embodiment, the filter has a mesh size of less than 100 μm, preferably less than 50 μm, more preferably less than 40 μm. When the filter comprises multiple filter layers, the finest mesh size is preferably less than 100 μm, preferably less than 50 μm, more preferably less than 40 μm.

[0092] According to one embodiment, the method of the present invention comprises extracting a hydrothermally treated mixed stream M3 (also referred to as a mixed stream rich in soluble substances) and extracting a mixed stream M5 that has not been hydrothermally treated (also referred to as a mixed stream poor in soluble substances). Preferably, according to this embodiment, the mixture M2 enters through the inlet E1 of the hydrothermal treatment reactor, the mixed stream M3 is discharged through the outlet S1 of the hydrothermal treatment reactor, and the mixed stream M5 is discharged through the outlet S2 of the hydrothermal treatment reactor. Advantageously, the height of the inlet E1 is lower than the height of the outlet S1 and higher than the outlet S2.

[0093] According to a particularly advantageous embodiment, the method of the invention also comprises at least one heat exchange step X1 allowing the recovery of heat from the mixed stream M3 (downstream of the heat exchange X1, the cooled mixed stream will be referred to as mixed stream M3') in order to at least partially heat the water to be injected in step b). Typically, according to this embodiment, the method of the invention also comprises at least one water heating step downstream of said heat exchange X1 for heating the water to at least 374°C before injecting it in step b).

[0094] When the process of the invention comprises a heat exchange step X1, said heat exchange step X1 is preferably carried out with water at a pressure of at least 225 bar and is therefore preferably carried out after a step of pressurizing the water W1 to at least 225 bar.

[0095] According to one embodiment, the method of the invention further comprises a heat exchange step X2 for recovering heat from the mixed flow M3 (preferably from the mixed flow M3' when a first heat exchange X1 is present) in order to heat the mixture M1p upstream of the water injection in step b) of the method. This heat exchange makes it possible to obtain a cooled mixed flow M3".

[0096] The temperature of the mixed flow M1p downstream of the heat exchange X2 is typically between 90°C and 170°C.

[0097] The temperature of the mixed stream M3" is typically between 100 and 200°C.

[0098] Preferably, according to this embodiment, the hydrothermal treatment method according to the present invention further comprises:

[0099] - a cooling step of at least a portion of the stream M3″ to obtain steam and a stream M4 comprising the hydrothermally treated organic matter, and

[0100] - a step of injecting at least a portion of steam for preheating the mixture M1 upstream of the pressurization step a).

[0101] The cooling step can be carried out by a cooling device selected from a heat exchanger, a flash evaporator or a scrubber integrated or not integrated in a rankine cycle, preferably a flash evaporator is used.

[0102] According to this embodiment, the steam generated during cooling is used to preheat the mixture M1 upstream of the pressurization step a).

[0103] Preferably, according to this embodiment, the mixture M1 is preheated upstream of the pressurization step a) to a temperature ranging from 50° C. to 160° C., preferably from 50° C. to 90° C., by means of the steam generated by cooling at least a portion of the mixture flow M3″. It should be noted that the mixture M1 may already be in a pressurized state before step a) defined in the present invention, step a) therefore making it possible to increase the pressure of the mixture M1.

[0104] Therefore, the present invention can better optimize the viscosity of biomass subjected to high pressure treatment.In fact, pumping at these high pressures is very difficult, so the viscosity of the biomass to be pumped is required to be minimal to meet the specifications of the ultra-high pressure pump.

[0105] By injecting steam into the mixture M1 , all possibilities are exploited to reduce the viscosity of the biomass to values ​​acceptable for pumping technology, while minimizing dilution of the biomass which can lead to additional costs for the size of the downstream equipment (need to comply with residence times, etc.).

[0106] According to one embodiment, the cooling of at least a portion of the mixed flow M3 ′ or, where appropriate, M3 ″ is carried out at a pressure adjusted as a function of the preheating temperature of the mixture M1 upstream of the pressurization step a).

[0107] In fact, for saturated steam, pressure and temperature are linked. Maintaining a constant pressure makes it possible to control the temperature of the steam and thus the maximum temperature that the product heated by the steam (in this case, the mixture M1) can reach.

[0108] For example, the pressure may be maintained between 2 and 10 bar.

[0109] According to one embodiment, the method according to the invention further comprises a supplementary cooling step, cooling at least a portion of the mixed stream M4 comprising the hydrothermally treated organic matter to obtain a mixed stream M4', which is then introduced into a digester to allow digestion of the organic matter contained in the mixed stream M4'.

[0110] The supplementary cooling step may, for example, cool the mixed stream M4 to a temperature less than or equal to 100°C, preferably less than or equal to 60°C, more preferably less than or equal to 40°C.

[0111] According to one embodiment, the cooled mixed stream M4' is subsequently introduced into a digester to undergo a digestion step.

[0112] Digestion can be carried out according to any digestion process known to those skilled in the art.

[0113] According to one embodiment, the treatment method according to the invention comprises at least one anaerobic digestion step, subjecting at least a portion of the mixed flow M4', preferably the entire mixed flow M4', to anaerobic digestion.

[0114] Anaerobic digestion can be either mesophilic or thermophilic.

[0115] When mesophilic digestion is carried out, the temperature in the digester is 33°C to 37°C and the residence time is 16 to 22 days.

[0116] When thermophilic digestion is carried out, the temperature in the digester is 55°C to 60°C and the residence time is 10 to 12 days.

[0117] Residence time and temperature are two factors that influence good sludge degradation and optimize energy production.

[0118] When the mixed stream to be digested is sufficiently liquid, the digestion can be of UASB type and the residence time can be shortened.

[0119] At the end of the digestion step, biogas is obtained.

[0120] Such biogas typically contains a mixture consisting essentially of methane, carbon dioxide and water. Biogas may optionally also contain other gases, such as hydrogen, oxygen, nitrogen or hydrogen sulfide, but these other gases together account for less than 10% of the total weight of the biogas.

[0121] One embodiment According to one embodiment, the method according to the invention further comprises one or more preheating steps, preheating the mixture M1p to, for example, 90° C. to 300° C., preferably 90° C. to 170° C. At least one of the preheating steps can be carried out, for example, by heat exchange X2 with the heat present in the mixed stream M3' obtained after a first heat exchange X1 with the mixed stream M3 containing the hydrothermally treated organic matter from step c). Such a heat exchange X2 step can be combined with another external heating step to heat the mixture M1p to the desired temperature.

[0122] According to one embodiment, the method according to the invention further comprises a (further) step of injecting water ES2 having a temperature of at least 374° C. directly into the hydrothermal treatment reactor, this step being called step d).

[0123] Preferably, the water injected directly into the hydrothermal treatment reactor has the same temperature and pressure as the water injected in step b) of the process of the invention. According to one embodiment, the water ES2 injected into the reactor is obtained in the same way as the water injected in step b) already described (advantageously by heat exchange X1 followed by supplementary heating). This helps to minimize equipment requirements and energy consumption.

[0124] Preferably, both water ES and water ES2 are supercritical water (having a temperature of at least 374° C. and a pressure of at least 225 bar).

[0125] Typically, according to this embodiment, the hydrothermal treatment reactor comprises, in addition to the inlet for introducing the mixed stream M2, a second inlet E2 for introducing water ES2 (water having a temperature of at least 374° C.). The second inlet E2 is preferably located at the bottom of the reactor. More specifically, if the mixed stream M2 is introduced from the inlet E1 at the upper part of the hydrothermal treatment reactor, the water ES2 will preferably be introduced from the inlet E2 at the lower part of the hydrothermal treatment reactor.

[0126] According to one embodiment, the water ES2 is introduced into the hydrothermal treatment reactor in a vertical direction, preferably from the bottom to the top with respect to gravity.

[0127] According to one embodiment, the mixed stream M3 comprising the hydrothermally treated organic matter is recovered through an outlet at the upper part of the reactor, and the reactor further comprises an outlet at the lower part of the reactor.

[0128] Within the meaning of the present invention, the expression "lower" is the opposite of the expression "upper". Thus, the height of the upper outlet is higher than the lower outlet. Similarly, the height of the upper outlet is also higher than the lower inlet.

[0129] According to one embodiment, the step of injecting water directly into the reactor is carried out through the inlet E2 of the lower part of the reactor, while the discharge of the mixed stream M3 is preferably carried out through the outlet S1 of the upper part of the reactor.

[0130] Therefore, in the implementation of water injection ES2 and extraction of materials that have not been hydrothermally treated (poor in soluble materials), preferably, relative to the hydrothermal treatment reactor, the height of the inlet E1 of the material M2 is lower than the outlet S1 of the material M3, and the height of the inlet E1 of the material M2 is higher than the outlet S2 of the material M5 and higher than the inlet E2 of the water ES2. Therefore, this configuration can optimize the residence time and promote the solubilization of the material in the reactor.

[0131] According to one embodiment, at least part of the mixed flow M3 containing the hydrothermally treated organic matter discharged from the reactor is sent to one or more subsequent treatment steps.

[0132] Among the subsequent treatments that may be carried out, a supplementary heating step and a hydrothermal gasification step may be cited. According to this embodiment, the heat exchange (X1, X2) and the digestion described in the present invention will be carried out downstream of the subsequent treatments, if appropriate.

[0133] According to one embodiment, the hydrothermal treatment method of the present invention comprises:

[0134] a) pressurizing a mixture M1, which may be already in a pressurized state, and which contains at least an organic substance, to obtain a pressurized mixture flow M1p,

[0135] b) injecting water at a temperature of at least 374°C and a pressure of at least 225 bar into the mixed flow M1p at an angle of 45° to 75° to obtain a mixed flow M2 comprising water and organic matter,

[0136] c) introducing the mixed stream M2 into a hydrothermal treatment reactor maintained at a temperature ranging from 150° C. to 430° C., so as to obtain a mixed stream M3 comprising hydrothermally treated organic matter,

[0137] The method further comprises:

[0138] - a step of pressurizing the water to at least 225 bar,

[0139] a heat exchange step X1, downstream of the water pressurization step, which allows the recovery of heat from the mixed stream M3 in order to at least partially heat the water to be injected in step b) and, where appropriate, the water ES2 to be injected in step d), so as to obtain a cooled mixed stream M3' and a heated water stream W2 downstream of the heat exchange X1,

[0140] a supplementary heating step downstream of said heat exchange step X1, of the heated water stream W2, making it possible to heat the water W2 to a temperature of at least 374°C before injecting it into step b), and, where appropriate, also to heat the water ES2 to be injected into step d), to a temperature of at least 374°C,

[0141] a heat exchange step X2, located downstream of the heat exchange step X1, which allows the recovery of heat from the mixed stream M3' in order to heat the mixture M1p before the water injection in step b) of the process and, if appropriate, to heat the water ES2 to be injected in step d), after which a cooled mixed stream M3" is obtained.

[0142] According to one embodiment, the hydrothermal treatment method of the present invention comprises:

[0143] a) pressurizing a mixture M1, which may be already in a pressurized state, and which contains at least an organic substance, to obtain a pressurized mixture flow M1p,

[0144] b) injecting water at a temperature of at least 374° C. and a pressure of at least 225 bar into the mixed flow M1p at an angle of 15° to 90° to obtain a mixed flow M2 comprising water and organic matter,

[0145] c) introducing the mixed stream M2 into a hydrothermal treatment reactor maintained at a temperature ranging from 150° C. to 430° C., so as to obtain a mixed stream M3 comprising hydrothermally treated organic matter,

[0146] The method further comprises:

[0147] - upstream of step c), a step of introducing the mixed flow M2 into a static turbulator,

[0148] - a step of pressurizing the water to at least 225 bar,

[0149] a heat exchange step X1, downstream of the water pressurization step, which allows the recovery of heat from the mixed stream M3 in order to at least partially heat the water to be injected in step b) and, where appropriate, the water ES2 to be injected in step d), so as to obtain a cooled mixed stream M3' and a heated water stream W2 downstream of the heat exchange X1,

[0150] a supplementary heating step downstream of said heat exchange step X1, of supplementary heating of the heated water stream W2, making it possible to heat the water W2 to a temperature of at least 374°C before injecting it into step b),

[0151] a heat exchange step X2, located downstream of the heat exchange step X1, which allows the recovery of heat from the mixed stream M3' in order to heat the mixture M1p before the water injection in step b) of the process and, if appropriate, to heat the water ES2 to be injected in step d), after which a cooled mixed stream M3" is obtained.

[0152] According to one embodiment, the hydrothermal treatment method of the present invention comprises:

[0153] a) pressurizing a mixture M1, which may be already in a pressurized state, and which contains at least an organic substance, to obtain a pressurized mixture flow M1p,

[0154] b) injecting water at a temperature of at least 374°C and a pressure of at least 225 bar into the mixed flow M1p at an angle of 45° to 75° to obtain a mixed flow M2 comprising water and organic matter,

[0155] c) introducing the mixed stream M2 into a hydrothermal treatment reactor maintained at a temperature ranging from 150° C. to 430° C., so as to obtain a stream M3 comprising hydrothermally treated organic matter,

[0156] The method further comprises:

[0157] - upstream of step c), a step of introducing the mixed flow M2 into a static turbulator,

[0158] - a step of pressurizing the water to at least 225 bar,

[0159] a heat exchange step X1, downstream of the water pressurization step, which allows the recovery of heat from the mixed stream M3 in order to at least partially heat the water to be injected in step b) and, where appropriate, the water ES2 to be injected in step d), so as to obtain a cooled mixed stream M3' and a heated water stream W2 downstream of the heat exchange X1,

[0160] a supplementary heating step downstream of said heat exchange step X1, of the heated water stream W2, making it possible to heat the water W2 to a temperature of at least 374° C. before injecting it into step b), and, where appropriate, also to heat the water ES2 to be injected into step d),

[0161] a heat exchange step X2, located downstream of the heat exchange step X1, which allows the recovery of heat from the mixed stream M3' in order to heat the mixture M1p before the water injection in step b) of the process and, if appropriate, to heat the water ES2 to be injected in step d), after which a cooled mixed stream M3" is obtained.

[0162] According to one embodiment, the hydrothermal treatment method of the present invention comprises:

[0163] a) pressurizing a mixture M1, which may be already in a pressurized state, and which contains at least an organic substance, to obtain a pressurized mixture flow M1p,

[0164] b) injecting water at a temperature of at least 374°C and a pressure of at least 225 bar into the mixed flow M1p at an angle of 45° to 75° to obtain a mixed flow M2 comprising water and organic matter,

[0165] c) introducing the stream M2 into a hydrothermal treatment reactor maintained at a temperature of at least 150° C. to 430° C., so as to obtain a mixed stream M3 comprising hydrothermally treated organic matter,

[0166] The method further comprises:

[0167] - a step of pressurizing the water to at least 225 bar,

[0168] a heat exchange step X1, downstream of the water pressurization step, which allows the recovery of heat from the mixed stream M3 in order to at least partially heat the water to be injected in step b) and, where appropriate, the water ES2 to be injected in step d), so as to obtain a cooled mixed stream M3' and a heated water stream W2 downstream of the heat exchange X1,

[0169] a supplementary heating step downstream of said heat exchange step X1, of supplementary heating of the heated water stream W2, making it possible to heat the water W2 to a temperature of at least 374°C before injecting it into step b),

[0170] a heat exchange step X2, downstream of the heat exchange step X1, which allows the recovery of heat from the mixed stream M3' in order to heat the mixture M1p before the water injection in step b) of the process and, if appropriate, the water ES2 to be injected in step d), after which a cooled mixed stream M3" is obtained

[0171] - a cooling step of cooling at least a portion of the mixed stream M3″ to obtain steam and a mixed stream M4 comprising the hydrothermally treated organic matter, and

[0172] - a steam injection step of injecting at least part of said steam upstream of the pressurization step a) in order to preheat the mixture M1.

[0173] According to one embodiment, the hydrothermal treatment method of the present invention comprises:

[0174] a) pressurizing a mixture M1, which may be already in a pressurized state, and which contains at least an organic substance, to obtain a pressurized mixture flow M1p,

[0175] b) injecting water at a temperature of at least 374° C. and a pressure of at least 225 bar into the mixed flow M1p at an angle of 15° to 90° to obtain a mixed flow M2 comprising water and organic matter,

[0176] c) introducing the stream M2 into a hydrothermal treatment reactor maintained at a temperature ranging from 150° C. to 430° C., so as to obtain a mixed stream M3 comprising hydrothermally treated organic matter,

[0177] The method further comprises:

[0178] - upstream of step c), a step of introducing the mixed flow M2 into a static turbulator,

[0179] - a step of pressurizing the water to at least 225 bar,

[0180] a heat exchange step X1, downstream of the water pressurization step, which allows the recovery of heat from the mixed stream M3 in order to at least partially heat the water W1 to be injected in step b) and, where appropriate, the water ES2 to be injected in step d), so as to obtain a cooled mixed stream M3' and a heated water stream W2 downstream of the heat exchange X1,

[0181] a supplementary heating step downstream of said heat exchange step X1, of the heated water stream W2, making it possible to heat the water W2 to a temperature of at least 374° C. before injecting it into step b), and, where appropriate, also to heat the water ES2 to be injected into step d),

[0182] a heat exchange step X2, downstream of the heat exchange step X1, which allows the recovery of heat from the mixed stream M3' in order to heat the mixture M1p before the water injection in step b) of the process and, if appropriate, the water ES2 to be injected in step d), after which a cooled mixed stream M3" is obtained

[0183] - a cooling step of cooling at least a portion of the mixed stream M3″ to obtain steam and a mixed stream M4 comprising the hydrothermally treated organic matter, and

[0184] - a steam injection step of injecting at least part of said steam upstream of the pressurization step a) in order to preheat the mixture M1.

[0185] According to one embodiment, the hydrothermal treatment method of the present invention comprises:

[0186] a) pressurizing a mixture M1, which may be already in a pressurized state, and which contains at least an organic substance, to obtain a pressurized mixture flow M1p,

[0187] b) injecting water at a temperature of at least 374°C and a pressure of at least 225 bar into the mixed flow M1p at an angle of 45° to 75° to obtain a mixed flow M2 comprising water and organic matter,

[0188] c) introducing the stream M2 into a hydrothermal treatment reactor maintained at a temperature ranging from 150° C. to 430° C., so as to obtain a mixed stream M3 comprising hydrothermally treated organic matter,

[0189] The method further comprises:

[0190] - upstream of step c), a step of introducing the mixed flow M2 into a static turbulator,

[0191] - a step of pressurizing the water to at least 225 bar,

[0192] a heat exchange step X1, downstream of the water pressurization step, which allows the recovery of heat from the mixed stream M3 in order to at least partially heat the water W1 to be injected in step b) and, where appropriate, the water ES2 to be injected in step d), so as to obtain a cooled mixed stream M3' and a heated water stream W2 downstream of the heat exchange X1,

[0193] a supplementary heating step downstream of said heat exchange step X1, of the heated water stream W2, making it possible to heat the water W2 to a temperature of at least 374° C. before injecting it into step b), and, where appropriate, also to heat the water ES2 to be injected into step d),

[0194] a heat exchange step X2, downstream of the heat exchange step X1, which allows the recovery of heat from the mixed stream M3' in order to heat the mixture M1p before the water injection in step b) of the process and, if appropriate, the water ES2 to be injected in step d), after which a cooled mixed stream M3" is obtained

[0195] - a cooling step of cooling at least a portion of the mixed stream M3″ to obtain steam and a mixed stream M4 comprising the hydrothermally treated organic matter, and

[0196] - a steam injection step of injecting at least part of said steam upstream of the pressurization step a) in order to preheat the mixture M1.

[0197] A further subject matter of the invention is a plant for carrying out the hydrothermal treatment method according to the invention.

[0198] The device according to the invention comprises:

[0199] - a feed line for the mixture M1, possibly under pressure,

[0200] a booster pump 2, supplied by the feed line of the mixture M1 and comprising an outlet line of the mixture M1p,

[0201] - means for injecting water ES, for injecting water ES at an angle of 15° to 90° into the line of mixture M1p downstream of the booster pump 2, so as to obtain a mixture flow M2,

[0202] a feed line for the mixed stream M2, downstream of the means for injection of water ES and upstream of the hydrothermal treatment reactor,

[0203] A hydrothermal treatment reactor 1 comprising at least one inlet E1 and at least one outlet S1 for the mixed flow M3 .

[0204] According to one embodiment, the hydrothermal treatment reactor 1 further comprises at least one outlet S2 of the mixed flow M5 and / or at least one inlet E2 for introducing water directly into the reactor 1. Preferably, the height of the inlet E1 is lower than the outlet S1, more preferably, the height of the inlet E1 is higher than the outlet S2, and advantageously, the height of the outlet S1 is higher than the inlet E2. This configuration makes it possible to optimize the residence time and solubilization effect of the material in the reactor.

[0205] Figures 1 to 6 An embodiment of a device for carrying out the method according to the invention is shown.

[0206] The equipment includes a feed pipeline for the mixture M1, a booster pump 2, a feed pipeline for supercritical water ES (which is connected to the pipeline of the mixture M1p downstream of the booster pump 2 at an angle α), and a hydrothermal treatment reactor 1, wherein the hydrothermal treatment reactor 1 includes an outlet S1 for the mixture flow M3 and an outlet S2 for the material M5 that has not been hydrothermally treated.

[0207] According to one embodiment, the apparatus further comprises a static turbulator 10 fed by a pipeline of the mixed flow M2, the static turbulator being located upstream or at the inlet of the hydrothermal treatment reactor 1. The mixture leaving the turbulator 10 can thus be fed to the hydrothermal treatment reactor 1. Figure 2 and Figure 6 Shown in.

[0208] The static turbulators may be selected from propellers, blades, pipe elbows or combinations thereof. Thus, for example, the supply line of the mixed flow M2 between the injection device of the water ES and the hydrothermal treatment reactor 1 may comprise one or more pipe elbows to provide turbulence and thus improve the exchange between water and sludge.

[0209] like Figure 2 As shown, turbulator 10 may include a conduit elbow.

[0210] According to one embodiment, the hydrothermal treatment reactor 1 comprises separation means, such as one or more filters.

[0211] The filter may comprise one or more filter layers, each layer optionally having a different mesh size, preferably the mesh size of the outer filter layer being larger than the mesh size of the inner filter layer.

[0212] According to one embodiment, the mesh size of the filter is less than 100 μm, preferably less than 50 μm, more preferably less than 40 μm. When the filter comprises multiple filter layers, the finest mesh size is preferably less than 100 μm, preferably less than 50 μm, more preferably less than 40 μm.

[0213] according to Figures 2 to 6In the embodiment shown, the device also comprises water injection means for injecting water ES2 directly into the hydrothermal treatment reactor via an inlet E2 preferably situated at the bottom of the reactor, thus allowing vertical injection from bottom to top.

[0214] Figure 3 An embodiment of the method according to the invention is shown. Figure 3 The illustrated plant shows a heat exchange step X1 via a heat exchanger 6. The heat exchanger 6 is used to recover heat in the mixed stream M3 leaving the hydrothermal treatment reactor 1 in order to transfer it to water W1 in order to preheat it before injecting it into the stream M1p.

[0215] according to Figure 3 In one embodiment shown, the device according to the present invention comprises:

[0216] a heat exchanger 6 located downstream of the hydrothermal treatment reactor, which is used to recover the heat of the mixed flow M3 to obtain a cooled mixed flow M3' and to transfer this heat to the water W1 upstream of the water injection device ES to obtain a heated water flow W2,

[0217] A water heating device 7 located downstream of the heat exchanger 6 and upstream of the water injection device ES, said water heating device 7 being supplied by the water W2 and making available water ES having a temperature of at least 374°C.

[0218] According to one embodiment not shown, the plant comprises, on the supply line of water W1 upstream of the heat exchanger 6 , a pressure pump which advantageously makes it possible to pressurize the water to at least 225 bar.

[0219] According to an advantageous embodiment, when the device comprises injection means of water ES2 , the device also comprises a water supply line connecting the heat exchanger 6 , or where appropriate the heat exchanger 7 , to the injection means of water ES2 .

[0220] Figure 4 An embodiment of the method according to the present invention is shown. The device shown comprises:

[0221] a heat exchanger 6 located downstream of the hydrothermal treatment reactor 1, capable of recovering the heat of the mixed flow M3, so as to obtain a mixed flow M3', and transferring this heat to the water W1 upstream of the heating device 7, so as to obtain heated water W2,

[0222] a water heating device 7, located downstream of the heat exchanger 6 and upstream of the injection device of the water ES, supplied with heated water W2,

[0223] a cooling device 4 to which at least a part of the mixed flow M3' is fed in order to produce steam and a cooled mixed flow M4,

[0224] - a steam injection device 3, used to inject the generated steam into the mixed flow M1 upstream of the booster pump 2, the steam injection device 3 can be a reactor,

[0225] a cooling device 9 downstream of the cooling device 4 for cooling at least a portion of the mixed flow M4 to obtain a mixed flow M4', and

[0226] - Digester 5, which is fed by the mixed flow M4'.

[0227] Figure 5 An embodiment of the method according to the present invention is shown. Figure 5 The device shown comprises:

[0228] a heat exchanger 6 located downstream of the hydrothermal treatment reactor 1, capable of recovering the heat of the mixed flow M3, so as to obtain a mixed flow M3', and transferring this heat to the water W1 upstream of the heating device 7, so as to obtain heated water W2,

[0229] a water heating device 7, located downstream of the heat exchanger 6 and upstream of the injection device of the water ES, supplied with heated water W2,

[0230] a heat exchanger 8 capable of recovering heat from the mixture M3' to obtain a mixture M3", and transferring this heat to the mixture M1p upstream of the water ES injection device,

[0231] a cooling device 4 to which at least a part of the mixed flow M3 ″ is supplied in order to produce steam and a cooled mixed flow M4 ,

[0232] - a steam injection device 3, used to inject the generated steam into the mixed flow M1 upstream of the booster pump 2, the steam injection device 3 can be a reactor,

[0233] a cooling device 9 downstream of the cooling device 4 for cooling at least a portion of the mixed flow M4 to obtain a mixed flow M4', and

[0234] - A digester 5 which is fed with the mixed flow M4'.

[0235] Figure 6 and Figure 5 The difference is the presence of static turbulators 10 .

[0236] According to one embodiment not shown in the figures, the apparatus according to the invention further comprises at least one subsequent treatment device, which is fed with at least a portion of the mixed flow M3 downstream of the hydrothermal treatment reactor 1. When the apparatus further comprises at least one heat exchanger 6, the subsequent treatment device is located upstream of the heat exchanger 6. Preferably, the subsequent treatment device is selected from a supplementary heating step and a hydrothermal gasification step.

Claims

1. A hydrothermal treatment method for treating a mixture M1 containing at least organic matter, the method comprising: a) pressurizing a mixture M1 comprising at least an organic substance to obtain a mixture flow M1p, b) injecting water having a temperature of at least 374° C. into the mixed stream M1P at an angle of 15° C. to 90° C. to obtain a mixed stream M2 comprising water and organic matter, c) introducing the mixed stream M2 into a hydrothermal treatment reactor maintained at a temperature ranging from 150° C. to 430° C., so as to obtain a mixed stream M3 comprising hydrothermally treated organic matter.

2. The hydrothermal treatment method according to claim 1, wherein: The pressure of the water injected in step b) is at least 225 bar and the method optionally comprises the step of pressurizing the water to at least 225 bar.

3. The hydrothermal treatment method according to claim 1 or 2, wherein: Before introduction into the hydrothermal treatment reactor, the mixed flow M2 is introduced into a static turbulator, preferably selected from a propeller, a blade, one or more pipe elbows or a combination thereof.

4. The hydrothermal treatment method according to any one of claims 1 to 3, further comprising: at least one heat exchange step X1 for recovering heat from the mixed stream M3 in order to at least partially heat the water to be injected in step b) so as to obtain a cooled mixed stream M3', and optionally comprising at least one additional water heating step downstream of the heat exchange step X1 so as to heat the water to a temperature of at least 374°C before injecting it in step b), and - optionally at least one heat exchange step X2 for recovering heat from the mixed stream M3' in order to heat the mixture M1p before the injection of water in step b) so as to obtain a cooled mixed stream M3".

5. The hydrothermal treatment method according to claim 4, further comprising: at least one cooling step of cooling at least a portion of the mixed stream M3′ or, where appropriate, at least a portion of the mixed stream M3″ to obtain steam and a mixed stream M4 comprising the hydrothermally treated organic matter, and - a steam injection step of injecting at least a portion of said steam in order to preheat the mixture M1 upstream of the pressurization step a).

6. The hydrothermal treatment method according to any one of claims 1 to 5, wherein: Upstream of the pressurization step a) the mixture M1 is preheated to a temperature ranging from 50 to 160°C, preferably from 50 to 90°C.

7. The hydrothermal treatment method according to claim 5 or 6, wherein: At least a portion of said mixed stream M3' or, where appropriate, at least a portion of said mixed stream M3" is cooled at a pressure adjusted as a function of the preheating temperature of the mixture M1 upstream of the pressurization step a).

8. The hydrothermal treatment method according to any one of claims 5 to 7, further comprising a cooling step of cooling at least a portion of the mixed stream M4 to obtain a mixed stream M4', and performing at least one digestion step on at least a portion of the mixed stream M4'.

9. The hydrothermal treatment method according to any one of claims 1 to 8, wherein: When injecting water in step b), the temperature of the mixture M1p is 90°C to 300°C, preferably 90°C to 170°C.

10. The hydrothermal treatment method according to any one of claims 1 to 9, further comprising the step of injecting water at a temperature of at least 374°C directly into the hydrothermal treatment reactor, the water preferably having the same temperature and pressure as the water injected in step b).

11. The hydrothermal treatment method according to any one of claims 1 to 10, wherein: A mixed stream M3 containing the hydrothermally treated organic matter is recovered through an outlet at the upper part of the reactor, and the reactor also comprises an outlet at the lower part of the reactor.

12. The hydrothermal treatment method according to any one of claims 1 to 11, wherein The mixed stream M3 comprising the hydrothermally treated organic substances leaving the reactor may undergo one or more further subsequent treatment steps, if appropriate carried out upstream of the heat exchanges X1 and X2 .

13. An apparatus for implementing the hydrothermal treatment method according to any one of claims 1 to 12, the apparatus comprising: - a feed line for the mixture M1, a pressure pump (2) supplied by the feed line of the mixture M1 and comprising an outlet line of the mixture M1p, - a device for injecting water ES, for injecting water ES into the line of the mixture M1P downstream of the booster pump (2) at an angle of 15° to 90°, a feed line for the mixed stream M2, downstream of the means for injection of water ES and upstream of the hydrothermal treatment reactor, A hydrothermal treatment reactor (1) comprising at least one inlet for introducing at least a portion of the mixed flow M2 and at least one outlet for withdrawing the mixed flow M3.

14. The device according to the preceding claim, further comprising: a static turbine (10), fed with the mixed flow M2, said static turbine being situated upstream or at the inlet of the hydrothermal treatment reactor (1), and a heat exchanger (6) situated downstream of the hydrothermal treatment reactor (1), capable of recovering the heat of the mixed flow M3 in order to obtain a mixed flow M3' and transferring this heat to the water upstream of the means for injecting the water ES, and - Optional water heating means (7) situated downstream of the heat exchanger (6) and upstream of the means for injecting the water ES.

15. The device according to claim 13 or 14, further comprising: an optional heat exchanger (8) capable of recovering heat from the mixture M3' to obtain a mixture M3", and transferring this heat to the mixture M1P upstream of the means for injection of water ES, a cooling device (4) supplied with at least a portion of the mixed flow M3' or, where appropriate, the mixture M3", making it possible to produce steam and a cooling flow M4, - a steam injection device (3) for injecting the generated steam into the mixed flow M1 upstream of the booster pump (2), - optional cooling means (9), located downstream of the cooling means (4), which are supplied to at least a portion of the mixed flow M4, for cooling at least a portion of the mixed flow M4 to obtain a mixed flow M4', and - An optional digester (5) which is fed by the mixed flow M4'.

Images