Continuous hydrothermal carbonization system and method for high-water content biomass

Abstract

The present invention discloses a continuous hydrothermal carbonization system and method for high-water-content biomass. The system includes: a biomass storage tank, a hydrothermal carbonization reactor, a heat recovery unit, a solid-liquid separation device, an ammonia recovery unit, an anaerobic digestion unit, a combustion unit and a waste heat recovery unit. The system adopts a three-stage heating method to hydrothermally carbonize high-water-content biomass, thereby improving the efficiency of hydrothermal carbonization, and adopts a waste heat recovery device to recycle the waste heat after the reaction, thereby improving the efficiency of the entire system. Therefore, compared with other technologies in terms of economy, the equipment investment is small, the labor cost is low, and the water and electricity cost consumption is low. For a daily processing of 50 tons of high-water-content biomass (taking sludge as an example), the hydrothermal carbon produced by the system can generate an annual income of about 7 million yuan, and the hydrogen produced by the co-gasification of the hydrothermal carbon and coal belongs to a high-value scarce energy source, with considerable economic benefits.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrothermal carbonization, and in particular relates to a continuous hydrothermal carbonization system and method for high-water-content biomass. Background Art

[0002] Hydrothermal carbonization is a biomass value-added treatment method that has developed rapidly in recent years. It uses water as a reaction solvent to perform anoxic pyrolysis on high-water-content biomass at a suitable temperature (120-280°C) and in a sealed pressure vessel (pressure 1MPa-5MPa). After a series of complex chemical reactions such as hydrolysis, dehydration, and decarboxylation, the biomass raw materials are converted into multifunctional carbon-based materials (hydrothermal carbon) with high added value. In terms of energy density, the quality of hydrothermal carbon is close to that of peat and lignite. It can be directly burned as a composite solid fuel, and can also be used in many fields such as soil improvement, CO2 fixation, and pollutant adsorption. At present, there are high-temperature carbonization and hydrothermal carbonization technologies for drying high-water-content biomass. The hydrothermal carbonization process in existing invention patents often has problems such as low carbonization efficiency and difficulty in waste heat utilization. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, one object of the present invention is to provide a continuous hydrothermal carbonization system and method for high-water-content biomass, which has the characteristics of simple equipment and operation, low energy consumption in the reaction process and no need to add drugs.

[0004] In one aspect of the present invention, the present invention provides a continuous hydrothermal carbonization system for high-water-content biomass. According to an embodiment of the present invention, the system comprises:

[0005] A biomass storage tank, the biomass storage tank comprising a high-water-content biomass inlet and a preliminary heated high-water-content biomass outlet;

[0006] A hydrothermal carbonization reactor, the hydrothermal carbonization reactor comprising an inlet for preliminary heating of high-water-content biomass and an outlet for post-reaction biomass, the inlet for preliminary heating of high-water-content biomass being connected to the outlet for preliminary heating of high-water-content biomass;

[0007] A heat recovery unit, the heat recovery unit comprising a post-reaction biomass inlet, a first water inlet, a first steam outlet and a solid-liquid mixture outlet, the post-reaction biomass inlet is connected to the post-reaction biomass outlet, and the first steam outlet is connected to the biomass storage tank;

[0008] A waste heat recovery unit, the waste heat recovery unit includes a high-temperature flue gas inlet, a low-temperature heat transfer oil inlet, a second water inlet, a high-temperature heat transfer oil outlet, a second steam outlet and a heat exchange flue gas outlet, the second steam outlet is connected to the hydrothermal carbonization reactor, and the high-temperature heat transfer oil outlet is connected to the jacket on the hydrothermal carbonization reactor.

[0009] The continuous hydrothermal carbonization system for high-water-content biomass according to the embodiment of the present invention has the characteristics of simple equipment and operation, low energy consumption in the reaction process, and no need to add drugs. This system adopts a three-stage heating method to hydrothermally carbonize high-water-content biomass, which improves the efficiency of hydrothermal carbonization, and adopts a waste heat recovery device to recycle the waste heat after the reaction, thereby improving the efficiency of the entire system. Therefore, compared with other technologies in terms of economy, the equipment investment is small, the labor cost is low, and the water and electricity cost consumption is low. For the daily processing of 50 tons of high-water-content biomass (taking sludge as an example), the hydrothermal carbon produced by this system can generate an annual income of about 7 million yuan.

[0010] In addition, the high water content biomass continuous hydrothermal carbonization system according to the above embodiment of the present invention may also have the following additional technical features:

[0011] In some embodiments of the present invention, the system further comprises: a solid-liquid separation device, an ammonia recovery unit, an anaerobic digestion unit and a combustion unit.

[0012] In some embodiments of the present invention, a solid-liquid separation device comprises a solid-liquid mixture inlet, a filter cake outlet and a filtrate outlet, and the solid-liquid mixture inlet is connected to the solid-liquid mixture outlet; an ammonia recovery unit comprises a filtrate inlet, a condensed ammonia outlet, and a residual liquid product outlet, and the filtrate inlet is connected to the filtrate outlet; an anaerobic digestion unit comprises a residual liquid product inlet, a wastewater outlet and a methane outlet, and the residual liquid product inlet is connected to the residual liquid product outlet; a combustion unit comprises a methane inlet and a high-temperature flue gas outlet, the methane inlet is connected to the methane outlet, and the high-temperature flue gas outlet is connected to the high-temperature flue gas inlet.

[0013] In some embodiments of the present invention, the system further comprises a dryer, the dryer comprising a filter cake inlet and a hydrothermal carbon outlet, the filter cake inlet being connected to the filter cake outlet, thereby drying the filter cake to obtain hydrothermal carbon, in preparation for further utilization of the hydrothermal carbon.

[0014] In some embodiments of the present invention, the system further comprises a gasification device, the gasification device comprising a hydrothermal carbon inlet, a coal inlet and a hydrogen outlet, the hydrothermal carbon inlet and the hydrothermal carbon outlet being connected. Thus, the hydrothermal carbon is mixed with the coal for co-gasification to produce hydrogen, which is a high-value scarce energy source with considerable economic benefits.

[0015] In some embodiments of the present invention, the system further comprises a flue gas purification unit, the flue gas purification unit comprising a heat exchange flue gas inlet and a purified flue gas outlet, the heat exchange flue gas inlet being connected to the heat exchange flue gas outlet. Thus, the flue gas after heat exchange enters the flue gas purification unit for purification and then is discharged, thereby reducing environmental pollution.

[0016] In some embodiments of the present invention, the system further comprises a wastewater recovery unit, wherein the wastewater recovery unit comprises a wastewater inlet, and the wastewater inlet is connected to the wastewater outlet. Thus, the wastewater obtained after the anaerobic digestion reaction enters the wastewater recovery unit, thereby reducing environmental pollution.

[0017] In another aspect of the present invention, the present invention provides a method for continuous hydrothermal carbonization of high-water-content biomass. According to an embodiment of the present invention, the method comprises:

[0018] (1) supplying high-water-content biomass to a biomass storage tank for preliminary heating to obtain preliminary heated high-water-content biomass;

[0019] (2) supplying the preliminarily heated high-water-content biomass to a hydrothermal carbonization reactor for reaction to obtain reacted biomass;

[0020] (3) supplying the reacted biomass to a heat recovery unit to exchange heat with water to obtain first steam and a solid-liquid mixture, and supplying the first steam to the biomass storage tank of step (1);

[0021] (4) The high-temperature flue gas is supplied to a waste heat recovery unit to exchange heat with low-temperature heat transfer oil and water respectively, so as to obtain high-temperature heat transfer oil, second steam and heat exchange flue gas; the second steam is supplied to the hydrothermal carbonization reactor to contact with the preliminarily heated high-water-content biomass for a second stage of heating; and the high-temperature heat transfer oil is supplied to the jacket of the hydrothermal carbonization reactor for a third stage of heating.

[0022] According to the method for continuous hydrothermal carbonization of high-water-content biomass of the embodiment of the present invention, a three-stage temperature rise method is used to hydrothermally carbonize high-water-content biomass, thereby improving the efficiency of hydrothermal carbonization, and a waste heat recovery device is used to recycle waste heat after the reaction, thereby improving the efficiency of the entire system. Therefore, compared with other technologies in terms of economic efficiency, the equipment investment is small, the labor cost is low, and the water and electricity cost consumption is low. For a daily processing of 50 tons of high-water-content biomass (taking sludge as an example), the hydrothermal carbon produced by this method can generate an annual income of about 7 million yuan.

[0023] In addition, the method for continuous hydrothermal carbonization of high-water-content biomass according to the above embodiment of the present invention may also have the following additional technical features:

[0024] In some embodiments of the present invention, the method further includes: (5) supplying the solid-liquid mixture to a solid-liquid separation device for solid-liquid separation to obtain a solid product and a liquid product; (6) supplying the liquid product to an ammonia recovery unit for recovering ammonia to obtain ammonia and a remaining liquid product; (7) supplying the remaining liquid product to an anaerobic digestion unit for anaerobic digestion to obtain methane and wastewater; (8) supplying the methane to a combustion unit for combustion to obtain high-temperature flue gas, and supplying the high-temperature flue gas to the waste heat recovery unit of step (4).

[0025] In some embodiments of the present invention, the method further comprises: (9) supplying the solid product to a dryer for drying to obtain hydrothermal carbon; (10) supplying the hydrothermal carbon to a gasification device and mixing it with coal for co-gasification to obtain hydrogen. Thus, waste utilization is achieved while reducing environmental pollution. The hydrogen produced by co-gasification of the hydrothermal carbon and coal is a high-value scarce energy source with considerable economic benefits.

[0026] In some embodiments of the present invention, the method further comprises: (11) supplying the wastewater to a wastewater recovery unit for wastewater recovery; thereby, environmental pollution is reduced.

[0027] In some embodiments of the present invention, the method further comprises: (12) supplying the heat exchange flue gas to a flue gas purification unit for flue gas purification and discharging the flue gas after purification, thereby reducing environmental pollution.

[0028] In some embodiments of the present invention, in step (1), the high water content biomass is initially heated to 80°C-120°C.

[0029] In some embodiments of the present invention, in step (2), the reaction temperature in the hydrothermal carbonization reactor is 220-280°C.

[0030] In some embodiments of the present invention, in step (2), the reaction pressure in the hydrothermal carbonization reactor is 1 MPa-5 MPa.

[0031] Therefore, the three-stage heating method is used to hydrothermally carbonize high-water-content biomass, thereby improving the efficiency of hydrothermal carbonization.

[0032] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0034] Figure 1 The figure is a schematic diagram of the structure of a continuous hydrothermal carbonization system for high-water-content biomass according to an embodiment of the present invention.

[0035] Figure 2 It is a schematic structural diagram of a continuous hydrothermal carbonization system for high-water-content biomass according to another embodiment of the present invention.

[0036] Figure 3 It is a schematic structural diagram of a continuous hydrothermal carbonization system for high-water-content biomass according to another embodiment of the present invention.

[0037] Figure 4 The present invention is a schematic diagram of a continuous hydrothermal carbonization method for high-water-content biomass according to an embodiment of the present invention.

[0038] Figure 5 The present invention is a schematic flow chart of a continuous hydrothermal carbonization method for high-water-content biomass according to another embodiment of the present invention.

[0039] Figure 6 The present invention is a schematic flow chart of a continuous hydrothermal carbonization method for high-water-content biomass according to another embodiment of the present invention. DETAILED DESCRIPTION

[0040] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0041] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0042] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0044] In one aspect of the present invention, the present invention provides a high-water-containing biomass continuous hydrothermal carbonization system. According to an embodiment of the present invention, reference is made to Figure 1-3 The system includes: a biomass storage tank 100, a hydrothermal carbonization reactor 200, a heat recovery unit 300 and a waste heat recovery unit 800.

[0045] According to an embodiment of the present invention, referring to Figure 1 , the biomass storage tank 100 includes a high-water-content biomass inlet 101 and a preliminary heating high-water-content biomass outlet 102. The high-water-content biomass is fed into the biomass storage tank through the high-water-content biomass inlet 101, and the high-water-content biomass is preliminarily heated by the first low-pressure steam. Specifically, the high-water-content biomass includes but is not limited to sludge, carbonized straw, kitchen waste, livestock and poultry manure, etc. It should be noted that the embodiment of the present invention does not limit the heat source of the first low-pressure steam, as long as it can achieve preliminary heating of the high-water-content biomass, and those skilled in the art can choose according to actual needs.

[0046] According to an embodiment of the present invention, referring to Figure 1The hydrothermal carbonization reactor 200 includes a preliminary heating high-water-content biomass inlet 201 and a post-reaction biomass outlet 202, wherein the preliminary heating high-water-content biomass inlet 201 is connected to the preliminary heating high-water-content biomass outlet 102. The preliminarily heated high-water-content biomass enters the hydrothermal carbonization reactor 200 from the preliminarily heated high-water-content biomass inlet 201, and the second low-pressure steam is used to mix with the high-water-content biomass in the hydrothermal carbonization reactor to heat the biomass in the reactor to 120°C-150°C, and then the reactants are heated again by high-temperature heat transfer oil to heat the hydrothermal carbonization reaction temperature to 220-280°C, and the hydrothermal carbonization reaction is carried out, and the hydrothermal carbon after the reaction is discharged from the post-reaction biomass outlet 202. It should be noted that the embodiment of the present invention does not limit the heat source of the second low-pressure steam, as long as the biomass in the reactor can be further heated to 120°C-150°C, and those skilled in the art can select it according to actual needs. In addition, the embodiment of the present invention does not limit the heat source of the high-temperature heat transfer oil, as long as the biomass in the reactor can be further heated to 220-280° C., those skilled in the art can select it according to actual needs.

[0047] According to the embodiment of the present invention, specifically, the hydrothermal carbonization reactor 200 is a jacketed structure, wherein the middle layer is introduced with high-water-content biomass and the second low-pressure steam to carry out the hydrothermal carbonization reaction; the jacket layer is introduced with high-temperature heat-conducting oil to heat the reactants in the middle layer. It should be noted that the structure of the hydrothermal carbonization reactor is not subject to specific restrictions, and those skilled in the art can select it according to actual needs, as long as the three-stage heating method can be implemented to carry out hydrothermal carbonization of high-water-content biomass.

[0048] According to an embodiment of the present invention, referring to Figure 1The heat recovery unit 300 includes a post-reaction biomass inlet 301, a first low-pressure steam outlet 303 and a solid-liquid mixture outlet 302. The post-reaction biomass inlet 301 is connected to the post-reaction biomass outlet 202, and the first steam outlet 303 is connected to the biomass storage tank. The biomass after hydrothermal carbonization enters the heat recovery unit 300 from the post-reaction biomass inlet 301 for heat recovery, and its own temperature drops to 60-70°C before being discharged from the solid-liquid mixture outlet 302. The low-pressure steam generated by the heat recovery unit is discharged from the first low-pressure steam outlet 303 and enters the biomass storage tank, and is used as the first low-pressure steam to preliminarily heat the high-water-content biomass. The low-pressure steam generated by the heat recovery unit can heat the high-water-content biomass to 80°C-120°C. Specifically, the heat recovery unit uses a heat exchanger, and the high-temperature hydrothermal carbon exchanges heat with the low-temperature water, heats the water into low-pressure steam, and reduces the temperature of the high-temperature hydrothermal carbon to 60-70°C. The high-temperature hydrothermal carbon and water are not in direct contact, and the heat exchanger structure can be a shell-and-tube type, with the high-temperature hydrothermal carbon passing through the tube layer and water passing through the shell layer. Of course, the heat exchanger is not limited to the shell-and-tube structure. It should be noted that the structure of the heat recovery unit 300 is not subject to specific restrictions, and those skilled in the art can select it according to actual needs, as long as the high-temperature biomass after hydrothermal carbonization can be heat recovered.

[0049] According to an embodiment of the present invention, referring to Figure 1, the waste heat recovery unit 800 includes a high-temperature flue gas inlet 801, a high-temperature heat transfer oil outlet 802, a low-temperature heat transfer oil inlet 805, a second low-pressure steam outlet 803 and a heat exchange flue gas outlet 804. The hydrothermal carbonization reactor 200 includes a high-temperature heat transfer oil inlet 203 and a low-temperature heat transfer oil outlet 204. The high-temperature heat transfer oil outlet 802 is connected to the high-temperature heat transfer oil inlet 203, the low-temperature heat transfer oil inlet 805 is connected to the low-temperature heat transfer oil outlet 204, and the second steam outlet 803 is connected to the hydrothermal carbonization reactor 200. The high-temperature flue gas enters the waste heat recovery unit 800 from the high-temperature flue gas inlet 801, and firstly performs a primary heat exchange to heat the heat transfer oil to a temperature of about 300°C; then performs a secondary heat exchange to heat water to generate a second low-pressure steam, and its own temperature drops to 50-70°C. The second low-pressure steam is discharged from the second low-pressure steam outlet 803, enters the hydrothermal carbonization reactor, and mixes with the high-water biomass in the hydrothermal carbonization reactor to heat the biomass in the reactor to 120°C-150°C. The high-temperature heat transfer oil flows out from the high-temperature heat transfer oil outlet 802, and then enters the hydrothermal carbonization reactor from the high-temperature heat transfer oil inlet 203. The high-temperature heat transfer oil is used to indirectly heat the biomass in the hydrothermal carbonization reactor, and the hydrothermal carbonization reaction temperature is controlled to 220-280°C. The low-temperature heat transfer oil after heat exchange flows out from the low-temperature heat transfer oil outlet 204, and then enters the waste heat recovery unit 800 from the low-temperature heat transfer oil inlet 805 for heat exchange again. It should be noted that high-temperature flue gas is not limited to that produced by methane combustion. As long as the technical effect of producing high-temperature flue gas can be achieved, technicians in this field can choose according to their needs.

[0050] The continuous hydrothermal carbonization system for high-water-content biomass according to the embodiment of the present invention has the characteristics of simple equipment and operation, low energy consumption in the reaction process and no need to add drugs. This system adopts a three-stage heating method to hydrothermally carbonize high-water-content biomass, which improves the efficiency of hydrothermal carbonization, and adopts a waste heat recovery device to recycle the waste heat after the reaction, thereby improving the efficiency of the entire system. Therefore, compared with other technologies in terms of economy, the equipment investment is small, the labor cost is low, and the water and electricity cost consumption is low. For the daily processing of 50t of high-water-content biomass (taking sludge as an example), the hydrothermal carbon produced by this system can generate an annual income of about 7 million yuan, and the hydrogen produced by the co-gasification of its product hydrothermal carbon and coal belongs to a high-value scarce energy source with considerable economic benefits.

[0051] Further, according to an embodiment of the present invention, referring to Figure 2 The system also includes a solid-liquid separation device 400, an ammonia recovery unit 500, an anaerobic digestion unit 600 and a combustion unit 700.

[0052] According to an embodiment of the present invention, referring to Figure 2The solid-liquid separation device 400 includes a solid-liquid mixture inlet 401, a filter cake outlet 402 and a filtrate outlet 403, wherein the solid-liquid mixture inlet 401 is connected to the solid-liquid mixture outlet 302. The solid-liquid mixture discharged through the solid-liquid mixture outlet 302 enters the solid-liquid separation device through the solid-liquid mixture inlet 401 to obtain a solid product and a liquid product. It should be noted that the structure of the solid-liquid separation device is not specifically limited, and those skilled in the art can select it according to actual needs, as long as the solid product and the liquid product can be separated.

[0053] According to an embodiment of the present invention, referring to Figure 2 The ammonia recovery unit 500 includes a filtrate inlet 501, a condensed ammonia outlet 502, and a residual liquid product outlet 503. The filtrate inlet 501 is connected to the filtrate outlet 403. The liquid product enters the ammonia recovery unit 500 from the filtrate inlet 501, and the ammonia dissolved in the liquid is volatilized by heating the liquid product, and then condensed and recovered. The condensed ammonia is discharged from the condensed ammonia outlet 502. The residual liquid product is discharged from the residual liquid product outlet 503.

[0054] According to an embodiment of the present invention, referring to Figure 2 The anaerobic digestion unit 600 includes a residual liquid product inlet 601, a wastewater outlet 602 and a methane outlet 603, wherein the residual liquid product inlet 601 is connected to the residual liquid product outlet 503. The residual liquid of the ammonia recovery unit enters the anaerobic digestion unit 600 through the residual liquid product inlet 601, undergoes anaerobic digestion to produce methane, and the methane is discharged through the methane outlet 603. The generated wastewater is discharged through the wastewater outlet 602.

[0055] According to an embodiment of the present invention, referring to Figure 2 The combustion unit 700 includes a methane inlet 701 and a high-temperature flue gas outlet 702. The methane inlet 701 is connected to the methane outlet 603, and the high-temperature flue gas outlet 702 is connected to the high-temperature flue gas inlet 801. Methane enters the combustion unit through the methane inlet 701, and generates high-temperature flue gas after combustion. The high-temperature flue gas is discharged from the high-temperature flue gas outlet 702 and enters the waste heat recovery unit 800 to provide high-temperature flue gas for the waste heat recovery unit.

[0056] Further, refer to Figure 3 The system further includes: a dryer 1100 and a gasification device 1200 .

[0057] According to an embodiment of the present invention, referring to Figure 3The dryer 1100 includes a filter cake inlet 1101 and a hydrothermal carbon outlet 1102, and the filter cake inlet is connected to the filter cake outlet. The solid product obtained from the solid-liquid separation device enters the dryer through the filter cake inlet 1101, and is dried by the dryer to obtain hydrothermal carbon, which is discharged from the hydrothermal carbon outlet 1102. Thus, the filter cake is dried to obtain hydrothermal carbon, which is prepared for further use of the hydrothermal carbon.

[0058] According to an embodiment of the present invention, referring to Figure 3 The gasification device 1200 includes a hydrothermal carbon inlet 1201, a coal inlet 1202 and a hydrogen outlet 1203, and the hydrothermal carbon inlet and the hydrothermal carbon outlet are connected. The hydrothermal carbon obtained from the dryer enters the gasification device through the hydrothermal carbon inlet 1201, and the hydrothermal carbon is mixed with the coal for co-gasification to produce hydrogen, and the produced hydrogen is discharged from the hydrogen outlet 1203.

[0059] Further, refer to Figure 3 , the above system also includes: a flue gas purification unit 900.

[0060] According to an embodiment of the present invention, the flue gas purification unit 900 includes a flue gas inlet 901 and a purified flue gas outlet 902, and the flue gas inlet 901 is connected to the flue gas outlet 804. The flue gas generated by the waste heat recovery unit enters the flue gas purification unit through the flue gas inlet 901, and the purified flue gas is discharged through the purified flue gas outlet 902. Thus, the flue gas after heat exchange enters the flue gas purification unit for purification and then is discharged, thereby reducing environmental pollution.

[0061] Further, refer to Figure 3 The above system also includes: a wastewater recovery unit 1000.

[0062] According to an embodiment of the present invention, the wastewater recovery unit 1000 includes a wastewater inlet 1001, which is connected to the wastewater outlet 602. Wastewater generated from the anaerobic digestion unit enters the wastewater recovery unit through the wastewater inlet 1001 for wastewater recovery. Thus, the wastewater obtained after the anaerobic digestion reaction enters the wastewater recovery unit, reducing environmental pollution.

[0063] In another aspect of the present invention, the present invention provides a method for continuous hydrothermal carbonization of high-water-content biomass using the above system. Figure 4 , the method comprising:

[0064] S100: supplying high-water-content biomass to a biomass storage tank for preliminary heating to obtain preliminary heated high-water-content biomass;

[0065] In this step, the high water content biomass is sent into the biomass storage tank 100 through the high water content biomass inlet 101, and the high water content biomass is heated to 80°C-120°C under the action of the first low-pressure steam, and then sent into the hydrothermal carbonization reactor after preliminary heating of the high water content biomass outlet 102. Specifically, the high water content biomass includes but is not limited to sludge, carbonized straw, kitchen waste, livestock and poultry manure, etc. It should be noted that the embodiment of the present invention does not limit the heat source of the first low-pressure steam, as long as it can achieve preliminary heating of the high water content biomass, and those skilled in the art can choose according to actual needs.

[0066] S200: supplying the preliminarily heated high-water-content biomass to a hydrothermal carbonization reactor for reaction, so as to obtain reacted biomass;

[0067] In this step, the preliminarily heated high-water-content biomass enters the hydrothermal carbonization reactor 200 from the preliminarily heated high-water-content biomass inlet 201, and the preliminarily heated high-water-content biomass is mixed with the high-water-content biomass in the hydrothermal carbonization reactor by the second low-pressure steam, and the preliminarily heated high-water-content biomass is heated again, and the biomass in the reactor is heated to 120°C-150°C. The reactants in the middle layer are heated again by high-temperature heat-conducting oil, and the hydrothermal carbonization reaction temperature is controlled to 220-280°C, and the pressure is controlled at 1MPa-5MPa to carry out the hydrothermal carbonization reaction. The hydrothermal carbon after the reaction is discharged from the post-reaction biomass outlet 202. It should be noted that the embodiment of the present invention does not limit the heat source of the second low-pressure steam, as long as the biomass in the reactor can be heated to 120°C-150°C, and those skilled in the art can select according to actual needs. In addition, the embodiment of the present invention does not limit the heat source of the high-temperature heat-conducting oil, as long as the biomass in the reactor can be heated to 220-280°C, and those skilled in the art can select according to actual needs.

[0068] S300: supplying the reacted biomass to a heat recovery unit to exchange heat with water to obtain first steam and a solid-liquid mixture, and supplying the first steam to the biomass storage tank in step (1);

[0069] In this step, the biomass after hydrothermal carbonization enters the heat recovery unit 300 from the post-reaction biomass inlet 301 for heat recovery, and its own temperature drops to 60-70°C before being discharged from the solid-liquid mixture outlet 302. The first low-pressure steam generated by the heat recovery unit is discharged from the first low-pressure steam outlet 303 and enters the biomass storage tank to preliminarily heat the high-water biomass. Specifically, the heat recovery unit uses a heat exchanger, and the high-temperature hydrothermal carbon exchanges heat with the low-temperature water, heating the water into low-pressure steam, and reducing the temperature of the high-temperature hydrothermal carbon to 60-70°C.

[0070] S400: The high-temperature flue gas is supplied to the waste heat recovery unit to exchange heat with the low-temperature heat transfer oil and water respectively, so as to obtain high-temperature heat transfer oil, second steam and heat exchange flue gas, the second steam is supplied to the hydrothermal carbonization reactor to contact with the preliminarily heated high-water-content biomass for the second stage of heating, and then the high-temperature heat transfer oil is supplied to the jacket of the hydrothermal carbonization reactor for the third stage of heating.

[0071] In this step, the high-temperature flue gas is sent to the waste heat recovery unit 800 from the high-temperature flue gas inlet 801, and part of the heat is used to heat the heat transfer oil, and part of the heat is used to generate the second low-pressure steam. First, a primary heat exchange is performed to heat the heat transfer oil to about 300°C; then a secondary heat exchange is performed to heat the water to generate the second low-pressure steam, and its own temperature is reduced to 50-70°C. The second low-pressure steam is supplied to the hydrothermal carbonization reactor and mixed with the high-water biomass in the hydrothermal carbonization reactor to heat the biomass in the reactor to 120°C-150°C. The high-temperature heat transfer oil is supplied to the hydrothermal carbonization reactor, and the high-temperature heat transfer oil is used to indirectly heat the biomass in the hydrothermal carbonization reactor, and the hydrothermal carbonization reaction temperature is controlled to 220-280°C. After heat exchange, the low-temperature heat transfer oil enters the waste heat recovery unit for another heat exchange. It should be noted that the high-temperature flue gas is not limited to that produced by methane combustion. As long as the technical effect of generating high-temperature flue gas can be achieved, technicians in this field can choose according to their needs.

[0072] According to the continuous hydrothermal carbonization method of high-water-content biomass according to the embodiment of the present invention, a three-stage temperature increase method is used to hydrothermally carbonize the high-water-content biomass, thereby improving the efficiency of the hydrothermal carbonization, and a waste heat recovery device is used to recycle the waste heat after the reaction, thereby improving the efficiency of the entire system. Therefore, compared with other technologies in terms of economy, the equipment investment is small, the labor cost is low, and the water and electricity cost consumption is low. For a daily processing of 50 tons of high-water-content biomass (taking sludge as an example), the hydrothermal carbon produced by this method can generate an annual income of about 7 million yuan, and the hydrogen produced by the co-gasification of the hydrothermal carbon and coal belongs to a high-value scarce energy source, with considerable economic benefits.

[0073] Further, refer to Figure 5 , the method further comprises:

[0074] S500: supplying the solid-liquid mixture to a solid-liquid separation device for solid-liquid separation to obtain a solid product and a liquid product;

[0075] In this step, the solid-liquid mixture discharged through the solid-liquid mixture outlet 302 enters the solid-liquid separation device 400 through the solid-liquid mixture inlet 401 for solid-liquid separation to obtain a solid product and a liquid product.

[0076] S600: supplying the liquid product to an ammonia recovery unit to recover ammonia, so as to obtain ammonia and a remaining liquid product;

[0077] In this step, the liquid product enters the ammonia recovery unit 500 from the filtrate inlet 501, and the ammonia dissolved in the liquid is volatilized by heating the liquid product, and then condensed and recovered. The condensed ammonia is discharged from the condensed ammonia outlet 502. The remaining liquid product is discharged from the remaining liquid product outlet 503.

[0078] S700: supplying the remaining liquid product to an anaerobic digestion unit for anaerobic digestion to obtain methane and wastewater;

[0079] In this step, the residual liquid of the ammonia recovery unit enters the anaerobic digestion unit 600 through the residual liquid product inlet 601, undergoes anaerobic digestion to produce methane, and the methane is discharged through the methane outlet 603. The generated wastewater is discharged through the wastewater outlet 602.

[0080] S800: supplying the methane to a combustion unit for combustion to obtain high-temperature flue gas.

[0081] In this step, methane enters the combustion unit 700 from the methane inlet 701 and generates high-temperature flue gas after combustion. The high-temperature flue gas is discharged from the high-temperature flue gas outlet 702, and then the high-temperature flue gas is supplied to the waste heat recovery unit 800 to provide heat for the waste heat recovery unit.

[0082] Further, refer to Figure 6 , the method further comprises:

[0083] S900: supplying the solid product to a dryer for drying to obtain hydrothermal carbon;

[0084] In this step, the solid product obtained from the solid-liquid separation device enters the dryer 1100 through the filter cake inlet 1101, and is dried in the dryer to obtain hydrothermal carbon, which is discharged from the hydrothermal carbon outlet 1102. Thus, the filter cake is dried to obtain hydrothermal carbon, which is prepared for further use of the hydrothermal carbon.

[0085] S1000: The hydrothermal carbon is supplied to a gasification device and mixed with coal for co-gasification to obtain hydrogen.

[0086] In this step, the dried hydrothermal carbon enters the gasification device through the hydrothermal carbon inlet 1201, and the hydrothermal carbon is mixed with coal for co-gasification to produce hydrogen, which is discharged from the hydrogen outlet 1203. Thus, waste utilization is achieved, while environmental pollution is reduced, and the hydrogen produced by the co-gasification of the hydrothermal carbon and coal is a high-value scarce energy source with considerable economic benefits.

[0087] Further, refer to Figure 6, the method further comprises:

[0088] S1100: supplying the wastewater to a wastewater recovery unit for wastewater recovery.

[0089] In this step, the wastewater generated from the anaerobic digestion unit enters the wastewater recovery unit 1000 through the wastewater inlet 1001 for wastewater recovery, thereby reducing environmental pollution.

[0090] Further, refer to Figure 6 , the method further comprises:

[0091] S1200: supplying the heat exchange flue gas to a flue gas purification unit for flue gas purification, and discharging the flue gas after purification.

[0092] In this step, the flue gas generated by the waste heat recovery unit enters the flue gas purification unit 900 through the flue gas inlet 901 for purification, and the purified flue gas is discharged through the purified flue gas outlet 902. Thus, environmental pollution is reduced.

[0093] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0094] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A high-water-content biomass continuous hydrothermal carbonization system, characterized in that: include: A biomass storage tank, the biomass storage tank comprising a high-water-content biomass inlet and a preliminary heated high-water-content biomass outlet; A hydrothermal carbonization reactor, the hydrothermal carbonization reactor comprising an inlet for preliminary heating of high-water-content biomass and an outlet for post-reaction biomass, the inlet for preliminary heating of high-water-content biomass being connected to the outlet for preliminary heating of high-water-content biomass; A heat recovery unit, the heat recovery unit comprising a post-reaction biomass inlet, a first water inlet, a first steam outlet and a solid-liquid mixture outlet, the post-reaction biomass inlet is connected to the post-reaction biomass outlet, and the first steam outlet is connected to the biomass storage tank; A waste heat recovery unit, the waste heat recovery unit includes a high-temperature flue gas inlet, a low-temperature heat transfer oil inlet, a second water inlet, a high-temperature heat transfer oil outlet, a second steam outlet and a heat exchange flue gas outlet, the second steam outlet is connected to the hydrothermal carbonization reactor, the second steam performs a second stage of heating the preliminarily heated high-water-content biomass, the high-temperature heat transfer oil outlet is connected to the jacket on the hydrothermal carbonization reactor, and the high-temperature heat transfer oil performs a third stage of heating the preliminarily heated high-water-content biomass.

2. The high-water-content biomass continuous hydrothermal carbonization system according to claim 1, characterized in that: Also includes: A solid-liquid separation device, the solid-liquid separation device comprising a solid-liquid mixture inlet, a filter cake outlet and a filtrate outlet, the solid-liquid mixture inlet being connected to the solid-liquid mixture outlet; an ammonia recovery unit, the ammonia recovery unit comprising a filtrate inlet, a condensed ammonia outlet, and a residual liquid product outlet, the filtrate inlet being connected to the filtrate outlet; An anaerobic digestion unit, the anaerobic digestion unit comprising a residual liquid product inlet, a wastewater outlet and a methane outlet, the residual liquid product inlet being connected to the residual liquid product outlet; A combustion unit, wherein the combustion unit comprises a methane inlet and a high-temperature flue gas outlet, wherein the methane inlet is connected to the methane outlet, and the high-temperature flue gas outlet is connected to the high-temperature flue gas inlet.

3. The high-water-content biomass continuous hydrothermal carbonization system according to claim 2, characterized in that: Also includes: A dryer, the dryer comprising a filter cake inlet and a hydrothermal carbon outlet, the filter cake inlet being connected to the filter cake outlet; A gasification device, comprising a hydrothermal carbon inlet, a coal inlet and a hydrogen outlet, wherein the hydrothermal carbon inlet and the hydrothermal carbon outlet are connected.

4. The high-water-content biomass continuous hydrothermal carbonization system according to claim 1, characterized in that: Also includes: A flue gas purification unit comprises a heat exchange flue gas inlet and a purified flue gas outlet, wherein the heat exchange flue gas inlet is connected to the heat exchange flue gas outlet.

5. The high-water-content biomass continuous hydrothermal carbonization system according to claim 2, characterized in that: Also includes: A wastewater recovery unit comprises a wastewater inlet connected to a wastewater outlet.

6. A method for continuous hydrothermal carbonization of high-water-content biomass using the system according to any one of claims 1 to 5, characterized in that: include: (1) supplying high-water-content biomass to a biomass storage tank for preliminary heating to obtain preliminary heated high-water-content biomass; (2) supplying the preliminarily heated high-water-content biomass to a hydrothermal carbonization reactor for reaction to obtain reacted biomass; (3) supplying the reacted biomass to a heat recovery unit to exchange heat with water to obtain first steam and a solid-liquid mixture, and supplying the first steam to the biomass storage tank of step (1); (4) The high-temperature flue gas is supplied to a waste heat recovery unit to exchange heat with low-temperature heat transfer oil and water respectively, so as to obtain high-temperature heat transfer oil, second steam and heat exchange flue gas; the second steam is supplied to the hydrothermal carbonization reactor to contact with the preliminarily heated high-water-content biomass for a second stage of heating; and the high-temperature heat transfer oil is supplied to the jacket of the hydrothermal carbonization reactor for a third stage of heating.

7. The method according to claim 6, characterized in that Also includes: (5) supplying the solid-liquid mixture to a solid-liquid separation device for solid-liquid separation to obtain a solid product and a liquid product; (6) supplying the liquid product to an ammonia recovery unit to recover ammonia, so as to obtain ammonia and a remaining liquid product; (7) supplying the remaining liquid product to an anaerobic digestion unit for anaerobic digestion to obtain methane and wastewater; (8) The methane is supplied to a combustion unit for combustion to obtain high-temperature flue gas, and the high-temperature flue gas is supplied to the waste heat recovery unit of step (4).

8. The method according to claim 7, characterized in that Also includes: (9) supplying the solid product to a dryer for drying to obtain hydrothermal carbon; (10) The hydrothermal carbon is supplied to a gasification device and mixed with coal for co-gasification to obtain hydrogen.

9. The method according to claim 7, characterized in that: Also includes: (11) The wastewater is supplied to a wastewater recovery unit for wastewater recovery.

10. The method according to claim 7, characterized in that The method further comprises: (12) The heat exchange flue gas is supplied to a flue gas purification unit for flue gas purification, and then discharged after purification.

11. The method according to claim 6, characterized in that In step (1), the high water content biomass is initially heated to 80°C-120°C.

12. The method according to claim 6, characterized in that In step (2), the reaction temperature in the hydrothermal carbonization reactor is 220-280°C.

13. The method according to claim 6, characterized in that In step (2), the reaction pressure in the hydrothermal carbonization reactor is 1 MPa-5 MPa.

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