Method for producing solid fuel with reduced odor using energy-saving hydrothermal carbonization reaction of organic or inorganic waste, and solid fuel produced thereby

Abstract

The present invention is for solving the problems of existing hydrothermal carbonization processes, and relates to a method for producing a solid fuel with reduced odor using an energy-saving hydrothe

Description

TITLE OF DISCLOSURE: METHOD OF PRODUCING SOLID FUEL WITH REDUCED ODOR USING ENERGY-SAVING HYDROTHERMAL CARBONIZATION REACTION OF ORGANIC OR INORGANIC WASTE, AND SOLID FUEL PRODUCED THEREBY Technical Field [1] The present disclosure relates to a technology for producing an environmental-friendly solid fuel rich in calories by loading organic or inorganic waste into a hydrothermal carbonization reactor (HTC reactor) that is a pressure tank and by carbonizing the organic or inorganic waste using a hydrothermal carbonization reaction, and by subjecting a hydrothermally carbonized carbide (HTC) slurry that is the product of the hydrothermal carbonization reaction to solid-liquid separation, drying, and molding, sequentially. After completion of the hydrothermal carbonization in the HTC reactor, the residual steam inside the HTC reactor is supplied to another HTC reactor in which the hydrothermal carbonization starts, thereby saving energy used in the total processing. The present disclosure is also directed to a method and an apparatus capable of saving used energy by supplying the residual steam inside the HTC reactor after the completion of hydrothermal carbonization to a feedstock supply tank, and by supplying heat energy remaining in the HTC slurry stored in an HTC slurry storage tank after the hydrothermal carbonization to the feedstock supply tank through a heat exchanger and a heat exchange liquid circulation system, thereby efficiently saving energy used in the hydrothermal carbonization processing. Background Art [2] Techniques to produce a solid fuel by using organic or inorganic waste include drying, carbonization, semicarbonization, and hydrothermal carbonization. [3] The most widely-used technique to produce a solid fuel at the present is drying, and generally, organic or inorganic waste is mainly used for drying, but drying requires 800,000 kilocalories to 900,000 kilocalories of energy to gasify 1 ton of moisture and is not cost-effective. Furthermore, dry solid waste used for a fuel has an odor issue so that in reality the use of the solid waste has been gradually reduced. [4] To address the issue, carbonization and semi-carbonization have been developed and are now applied to some facilities, but those techniques emit substantial air-pollutants in the process although they consume 70% to 80% of the energy consumed in drying. Thus, carbonization and semicarbonization are known to have limitations in being applied to produce a solid fuel from organic or inorganic waste. [5] To address the limitations, active development to produce a solid fuel through hydrothermal carbonization is lately under way. Carbonization and semi-carbonization make it possible to proceed when organic or inorganic waste with 70% to 80% water of the total content is dried to become a product with 20% to 30% water of the total content, which requires substantial energy. Meanwhile hydrothermal carbonization does not need drying and successfully proceeds by heating organic or inorganic waste with 70% to 85% water of the total content at a temperature in a range of 200°C to 230°C for 1 hour to 3 hours. Drying requires gasification of moisture in a liquid so that a total of 800,000 kilocalories to 900,000 kilocalories including 560,000 kilocalories of latent heat of vaporization is required to gasify 1 ton of moisture. However, hydrothermal carbonization does not require conversion of a liquid into a gas and just needs heating at a temperature in a range of 200°C to 230°C, which means no need of latent heat of vaporization. Thus, hydrothermal carbonization consumes 40% to 50% of the energy consumed in drying and 60% to 70% of the energy consumed in carbonization and semi-carbonization. [6] Hydrothermal carbonization has many benefits unlike drying, carbonization, and semi-carbonization: energy-saving effect, reduction of odor from a produced solid fuel, reduction in air pollutant emitting in solid fuel production, and production of a solid fuel rich in calories. Thus, hydrothermal carbonization is expected to be more applied as a solid fuel producing technique from organic or inorganic waste down the road. However, hydrothermal carbonization with those many benefits still has a limitation as well of substantial energy consumption. [7] (Related Art Documents) [8] (Patent Document) [9] 1. Korean Patent No. 10-1,773,151 (2017. 08. 24.) Disclosure Technical Problem

[10] The present disclosure is to advance solid fuel producing by using organic or inorganic waste, thereby tasks below are dealt with.

[11] In other words, first, the present disclosure has an objective to provide a hydrothermal carbonization method and apparatuses for producing a solid fuel using organic or inorganic waste by adopting hydrothermal carbonization to address substantial energy consumption and odor generation from producing solid fuel.

[12] Second, the present disclosure has an objective to provide a hydrothermal carbonization method and its apparatuses for producing a solid fuel using organic or inorganic waste by adopting hydrothermal carbonization to address the issues of carbonization and semi-carbonization which generate substantial air-pollutants in solid fuel production and consume substantial energy.

[13] Third, the present disclosure has an objective to provide a hydrothermal carbonization method and its apparatuses which allow 65% to 75% energy saving compared with conventional hydrothermal carbonization since the conventional hydrothermal carbonization employed to address the issues of drying, carbonation, and semi-carbonization also has ongoing limitation of consuming substantial energy. Technical Solution

[14] The present disclosure achieves the above-mentioned objectives by: addressing substantial energy consumption and odor generation from producing a solid fuel in drying; addressing substantial energy consumption and substantial airpollutant emitting in carbonization and semi-carbonization; and addressing substantial energy consumption even in the conventional hydrothermal carbonization. With the achievement of the objectives, the present disclosure is to provide a method of producing a solid fuel with reduced odor through a new and advanced hydrothermal carbonization reaction having 65% to 75% energy-saving compared with the conventional hydrothermal carbonization and to provide a solid fuel produced by the method. The measures to address the issues are as follows.

[15] In other words, the present disclosure relates to a method of producing a solid fuel with reduced odor by using energy-saving hydrothermal carbonization reaction and a solid fuel produced by the method, the method including: pulverizing organic or inorganic waste into particles with a size in a range of 0.1 mm to 1 mm; mixing the pulverized organic or inorganic waste with water to prepare a mixture and storing the mixture in a feedstock supply tank; supplying the mixture contained in the feedstock supply tank to a first HTC reactor equipped with an agitator and causing an oxygen-blocked reaction within the first HTC reactor at a temperature in a range of 180°C to 230°C, under a pressure in a range of 10 to 27 bar for 1 hour to 2 hours; supplying the mixture contained in the feedstock supply tank to a second HTC reactor equipped with an agitator and causing an oxygen-blocked reaction in the second HTC reactor at a temperature in a range of 180 °C to 230°C, under a pressure in a range of 10 to 27 bar for 1 hour to 2 hours while the reaction proceeds in the first HTC reactor; transporting a hydrothermally carbonized carbide (HTC) slurry into an HTC slurry storage tank; and molding and drying the HTC slurry.

[16] Herein, "supplying the mixture contained in the feedstock supply tank to the first HTC reactor equipped with the agitator and causing the oxygen-blocked reaction within the first HTC reactor at a temperature in a range of 180 °C to 230°C, under a pressure in a range of 10 to 27 bar for 1 hour to 2 hours" is caused by steam having a high temperature in a range of 200°C to 230°C and under a pressure in a range of 15 to 27 bar and being supplied from a boiler.

[17] In addition, "supplying the mixture contained in the feedstock supply tank to the second HTC reactor equipped with the agitator and causing the oxygen-blocked reaction in the second HTC reactor at a temperature in a range of 180 °C to 230°C, under a pressure in a range of 10 to 27 bar for 1 hour to 2 hours while the reaction proceeds in the first HTC reactor" is caused by steam at a high temperature supplied from the first HTC reactor after the step completion of "supplying the mixture contained in the feedstock supply tank to the first HTC reactor equipped with the agitator and causing the oxygen-blocked reaction within the first HTC reactor at a temperature in a range of 180°C to 230°C, under a pressure in a range of 10 to 27 bar for 1 hour to 2 hours".

[18] Furthermore, the present disclosure further includes increasing of the internal temperature of the feedstock supply tank by supplying the high-temperature steam to the feedstock supply tank from the first and second HTC reactors after the completion of "supplying the mixture contained in the feedstock supply tank to the first HTC reactor equipped with the agitator and causing the oxygen-blocked reaction within the first HTC reactor at a temperature in a range of 180 °C to 230°C, under a pressure in a range of 10 to 27 bar for 1 hour to 2 hours" and "supplying the mixture contained in the feedstock supply tank to the second HTC reactor equipped with an agitator and causing the oxygen-blocked reaction in the second HTC reactor at a temperature in a range of 180 °C to 230°C, under a pressure in a range of 10 to 27 bar for 1 hour to 2 hours while the reaction proceeds in the first HTC reactor".

[19] Additionally, the present disclosure further includes increasing the internal temperature of the feedstock supply tank by supplying heat energy of the HTC slurry in an HTC slurry storage tank that has a temperature in a range of 85°C to 95°C, and in which the HTC slurry is contained after the completion of the "transporting the HTC slurry into the HTC slurry storage tank" to the feedstock supply tank through a heat exchanger and a heat exchange liquid circulation pipe.

[20] Herein, in the present disclosure, the internal temperature of the feedstock supply tank is increased to 20 °C to 50 °C by increasing of the internal temperature of the feedstock supply tank.

[21] In addition, in "mixing the pulverized organic or inorganic waste with water to prepare a mixture", a catalyst is additionally mixed to prepare the mixture.

[22] Herein, the catalyst is selected from the group consisting of an acid-based acid catalyst, a chloride-based acid catalyst, and a combination of the acid-based acid catalyst and the chloride-based acid catalyst, the acid-based acid catalyst being H2SO4, and the chloride-based acid catalyst being HC1, FeCls, and a combination of HC1 and FeCls. Thus, the present disclosure relates to a method of producing a solid fuel with reduced odor by using an energy-saving hydrothermal carbonization reaction with those catalysts.

[23] In "mixing the pulverized organic or inorganic waste with water to prepare a mixture", a catalyst is additionally mixed, and preferably, in the step, a ground additive having a size in a range of 0.1 mm to 1 mm is additionally mixed, and more preferably, additive ground having a size in a range of 0.5 mm to 1 mm is mixed.

[24] In addition, the raw materials of organic wastes include a variety of processed food wastes such as liguor residue, tofu residue, beans, red beans, sweet potatoes, and potatoes; agricultural wastes such as mushroom medium, vegetables, and fruits; livestock wastes such as beef powder, pork powder, chicken powder, and animal carcasses; marine wastes such as fish, oysters, seaweed, and wakame; and / or domestic wastes such as sewage sludge, food waste, coffee grounds, and garden waste, and the present disclosure is to provide a method of producing a solid fuel with reduced odor by using an energysaving hydrothermal carbonization reaction with the raw materials of organic wastes.

[25] The raw materials of inorganic wastes include dyeing wastewater sludge, leather wastewater sludge, leather wastewater sludge, paper wastewater sludge, mining wastewater sludge, and / or plating wastewater sludge, and the present disclosure is to provide a method of producing a solid fuel with reduced odor by using an energy-saving hydrothermal carbonization reaction with the raw materials of the inorganic wastes.

[26] Additionally, additives are preferable to be selected from biomass-based materials such as sawdust, and it is also preferable that the pulverized organic or inorganic waste is mixed with the biomass-based additive in a weight ratio of 19:1 to 4:1 (in other words, the weight percent of the biomass-based additive based on the total weight of the mixture with the pulverized organic or inorganic waste and the biomass-based additive is in a range of 5% by weight to 20% by weight) , and then water is mixed with an acid-based acid catalyst or a chloride-based acid catalyst before being added to the mixture so that the weight percent based on the total weight of the final mixture is in a range of 80% by weight to 90% by weight for moisture and in a range of 0.08% by weight to 3.6% by weight for a catalyst.

[27] Meanwhile, the present disclosure is to provide a solid fuel produced by using the method of producing a solid fuel with reduced odor by using an energy-saving hydrothermal carbonization reaction configured with the mentioned processing. Advantageous Effects

[28] The present disclosure is to provide an advanced method of producing a solid fuel with reduced odor by using a hydrothermal carbonization reaction for organic or inorganic waste and a solid fuel produced with the method, and the specific effects of the present disclosure are as follows.

[29] That is, first, the present disclosure adopts an advanced hydrothermal carbonization to produce a solid fuel by using organic or inorganic waste so that it provides a new hydrothermal carbonization method which addresses substantial energy consumption and odor generation from producing a solid fuel in drying and a solid fuel produced with the method.

[30] Second, the present disclosure adopts an advanced hydrothermal carbonization to produce a solid fuel by using organic or inorganic waste so that it provides a new hydrothermal carbonization method which addresses substantial energy consumption and substantial air-pollutant generation in carbonization and semi-carbonization and a solid fuel produced with the method.

[31] Third, the present disclosure addresses limitations of the conventional hydrothermal carbonization methods such as substantial energy consumption which have been adopted to deal with the problems of drying, carbonization, and semicarbonization. Thus, the present disclosure is to provide a very efficient and new hydrothermal carbonization method in which 65% to 75% energy is saved compared with the methods of conventional hydrothermal carbonization and a solid fuel produced with the method. Description of Drawings

[32] FIG. 1 is a diagram illustrating the process flow of an energy-saving hydrothermal carbonization for organic or inorganic waste; and

[33] FIG. 2 illustrates two photos of solid fuels rich in calories.

[34]

[35] (Description of reference numerals in the drawings)

[36] 10: first HTC reactor

[37] 20: second HTC reactor

[38] 31: steam release valve of first HTC reactor

[39] 32: steam release valve of second HTC reactor

[40] 33: valve for steam release of HTC reactor and boiler, and steam supply valve of first HTC reactor

[41] 34: valve for steam release of HTC reactor and boiler, and steam supply valve of second HTC reactor

[42] 41: residual steam release valve of first HTC reactor

[43] 42: residual steam release valve of second HTC reactor

[44] 50: boiler

[45] 51: main valve for steam supply from HTC reactor

[46] 60: feedstock supply tank

[47] 61: release valve of reactive steam from the feedstock supply tank

[48] 71: release valve of HTC slurry from first HTC reactor

[49] 72: release valve of HTC slurry from second HTC reactor

[50] 73: HTC slurry storage tank

[51] 80: heat exchanger for feedstock

[52] 81: heat exchange liquid circulation pipe Best Mode

[53] The present disclosure aims to address substantial energy consumption and odor generation from producing a solid fuel in drying, to address substantial energy consumption and substantial air-pollutant generation in solid fuel production in carbonization and semi-carbonization, and to save 65% to 75% energy by addressing substantial energy consumption even in conventional hydrothermal carbonization. To the end, the present disclosure is to provide a method of producing a solid fuel with reduced odor by using a new and advanced energysaving hydrothermal carbonization reaction and a solid fuel produced with the method.

[54] First, one embodiment of the method of producing a solid fuel with reduced odor by using an energy-saving hydrothermal carbonization reaction is as follows.

[55] That is, the producing method according to one embodiment of the present disclosure may be a method of producing a solid fuel with reduced odor by using an energy-saving hydrothermal carbonization reaction, the method including:

[56] 1) pulverizing organic or inorganic waste into particles with a size in a range of 0.1 mm to 1 mm;

[57] 2) mixing the pulverized organic or inorganic waste with water to prepare a mixture and storing the mixture in a feedstock supply tank;

[58] 3) supplying the mixture contained in the feedstock supply tank to a first HTC reactor equipped with an agitator and causing an oxygen-blocked reaction within the first HTC reactor at a temperature in a range of 180°C to 230°C, under a pressure in a range of 10 to 27 bar for 1 hour to 2 hours;

[59] 4) supplying the mixture contained in the feedstock supply tank to a second HTC reactor equipped with an agitator and causing an oxygen-blocked reaction in the second HTC reactor at a temperature in a range of 180°C to 230°C, under a pressure in a range of 10 to 27 bar for 1 hour to 2 hours while the reaction proceeds in the first HTC reactor;

[60] 5) transporting a hydrothermally carbonized carbide (HTC) slurry into an HTC slurry storage tank; and

[61] 6) molding and drying the HTC slurry.

[62] Herein, according to one embodiment, the "3) of supplying the mixture contained in the feedstock supply tank to the first HTC reactor equipped with the agitator and causing the oxygen-blocked reaction within the first HTC reactor at a temperature in a range of 180°C to 230°C, under a pressure in a range of 10 to 27 bar for 1 hour to 2 hours" means hydrothermal carbonization of the mixture (feedstock) supplied from the first HTC reactor, which may be a producing method caused by high-temperature steam supplied at a temperature in a range of 200°C to 230°C, under a pressure in a range of 15 to 27 bar from a boiler.

[63] According to one embodiment, the "4) of supplying the mixture contained in the feedstock supply tank to the second HTC reactor equipped with the agitator and causing the oxygen-blocked reaction in the second HTC reactor at a temperature in a range of 180°C to 230°C, under a pressure in a range of 10 to 27 bar for 1 hour to 2 hours while the reaction proceeds in the first HTC reactor" may be a producing method caused by a high-temperature steam supplied from the first HTC reactor after the completion of "supplying the mixture in the feedstock supply tank to the first HTC reactor equipped with the agitator and causing the oxygen-blocked reaction in the first HTC reactor at a temperature in a range of 180 °C to 230°C, under a pressure in a range of 10 to 27 bar for 1 hour to 2 hours".

[64] In addition, according to one embodiment, the present disclosure may be a producing method further including the increasing of an internal temperature of the feedstock supply tank by supplying steam at a high temperature to the feedstock supply tank from the first and second HTC reactors after the completion of the "3) of supplying the mixture contained in the feedstock supply tank to the first HTC reactor equipped with the agitator and causing the oxygen-blocked reaction within the first HTC reactor at a temperature in a range of 180°C to 230°C, under a pressure in a range of 10 to 27 bar for 1 hour to 2 hours" and the "4) of supplying the mixture contained in the feedstock supply tank to the second HTC reactor equipped with the agitator and causing the oxygen-blocked reaction in the second HTC reactor at a temperature in a range of 180°C to 230°C, under a pressure in a range of 10 to 27 bar for 1 hour to 2 hours while the reaction proceeds in the first HTC reactor".

[65] According to one embodiment, the present disclosure may be a producing method further including the increasing of the internal temperature of the feedstock supply tank by supplying heat energy of an HTC slurry storage tank at a temperature in a range of 85°C to 95°C and in which the HTC slurry is contained after the completion of the "5) transporting the HTC slurry into the HTC slurry storage tank" to the feedstock supply tank using a heat exchanger and a heat exchange liquid circulation pipe.

[66] Herein, according to one embodiment, the present disclosure may be a producing method in which the internal temperature of the feedstock supply tank is increased to 20 °C to 50 °C by increasing of the internal temperature of the feedstock supply tank.

[67] According to one embodiment, the "2) of mixing the pulverized organic or inorganic waste with water to prepare a mixture and storing the mixture in the feedstock supply tank" may be a producing method in which a catalyst is additionally mixed to prepare the mixture.

[68] According to one embodiment of the present disclosure, the catalyst is selected from the group consisting of an acidbased acid catalyst, a chloride-based acid catalyst, or a combination of the acid-based acid catalyst and the chloridebased acid catalyst, the acid-based acid catalyst being H2SO4, and the chloride-based acid catalyst being HC1, FeCls, or a combination of HC1 and FeCls. Thus, the present disclosure may be a method of producing a solid fuel with reduced odor by using an energy-saving hydrothermal carbonization reaction using those catalysts.

[69] According to one embodiment of the present disclosure, in "mixing the pulverized organic or inorganic waste with water to prepare a mixture", catalysts are additionally mixed, and preferably, a ground additive having a size in a range of 0.1 mm to 1 mm may be additionally mixed, and more preferably, an additive having a size in a range of 0.5 mm to 1 mm may be ground and mixed.

[70] In addition, according to one embodiment of the present disclosure, the raw materials of organic wastes include a variety of processed food wastes such as liquor residue, tofu residue, beans, red beans, sweet potatoes, and potatoes; agricultural wastes such as mushroom medium, vegetables, and fruits; livestock wastes such as beef powder, pork powder, chicken powder, and animal carcasses; marine wastes such as fish, oysters, seaweed, and wakame; and / or domestic wastes such as sewage sludge, food waste, coffee grounds, and garden waste, and the present disclosure may be a method of producing a solid fuel with reduced odor by using an energy-saving hydrothermal carbonization reaction for the raw materials of the organic wastes.

[71] According to one embodiment, the raw materials of inorganic wastes include dyeing wastewater sludge, leather wastewater sludge, leather wastewater sludge, paper wastewater sludge, mining wastewater sludge, and / or plating wastewater sludge, and the present disclosure may be a method of producing a solid fuel with reduced odor by using a hydrothermal carbonization reaction for the raw materials of the inorganic wastes.

[72] According to one embodiment of the present disclosure, additives are preferable to be selected from biomass-based materials such as sawdust, and it is also preferable that the pulverized organic or inorganic waste is mixed with the biomass-based additive in a weight ratio of 19:1 to 4:1 (in other words, the weight percent of the biomass-based additive based on the total weight of the mixture with the pulverized organic or inorganic waste and the biomass-based additive is in a range of 5% by weight to 20% by weight) , and then water is mixed with an acid-based acid catalyst or a chloride-based acid catalyst before being added to the mixture so that the weight percent based on the total weight of the final mixture is in a range of 80% by weight to 90% by weight for moisture and in a range of 0.08% by weight to 3.6% by weight for a catalyst.

[73]

[74] Meanwhile, according to one embodiment, the present disclosure may relate to a solid fuel produced by the method of producing a solid fuel with reduced odor by using an energy-saving hydrothermal carbonization reaction configured with the mentioned processing. Mode for Disclosure

[75] Hereinafter, a specific processing according to a method of producing a solid fuel with reduced odor by using an energy-saving hydrothermal carbonization reaction of the present disclosure will be described in the aspect of energy saving with reference to FIGS. 1 and 2.

[76] The present disclosure relates to a brilliant and energysaving method of producing a solid fuel capable of saving 65% to 75% of the required energy for the hydrothermal carbonization by efficiently recovering heat energy of residual steam at a high temperature in HTC reactors and of HTC slurry released from the HTC reactors after the completion of hydrothermal carbonization reaction and supplying heat energy once again which is necessary for the hydrothermal carbonization for waste.

[77] An energy recover for energy saving is implemented in 3 steps in producing a solid fuel with reduced odor by using an energy-saving hydrothermal carbonization reaction of the present disclosure.

[78] That is, a first step is a recover of heat energy from high-temperature steam inside a first HTC reactor by supplying steam at a high temperature in a range of 200°C to 250°C after the completion of hydrothermal carbonization reaction from a first HTC reactor to a second HTC reactor in which hydrothermal carbonization reaction starts, thereby 25% to 35% of the required energy may be saved.

[79] A second step is a recover of heat energy from residual steam inside the first and second HTC reactors by supplying residual steam at a relative high temperature in a range of 140°C to 150°C at the completion time of hydrothermal carbonization reaction in the second HTC reactor to a feedstock supply tank from the first HTC reactor already in the completion state of hydrothermal carbonization reaction and the second HTC reactor, thereby 20% to 30% of the required energy may be saved.

[80] A third step is a recover of heat energy from an HTC slurry in an HTC slurry tank by releasing an HTC slurry from the from the first and second HTC reactors after the completion of hydrothermal carbonization reaction, supplying heat energy of an HTC slurry stored in the HTC storage tank at a temperature in a range of 85°C to 95°C to a feedstock supply tank through a heat exchanger and a heat exchange liquid circulation pipe, and increasing the internal temperature of the feedstock supply tank, thereby 10% to 20% of the required energy may be saved.

[81] A further specific processing according to one embodiment of the present disclosure will be described below with reference to FIG. 1.

[82] Waste for hydrothermal carbonization was supplied from a feedstock supply tank 73 after the temperature rose in a closed heat exchanger for feedstock 80. The temperature of the mixture which was supplied to the heat exchanger for feedstock 80 differed, but the temperature was in a range of 20°C to 30°C on average, and a liquid for heat exchange which absorbed heat energy at a temperature in a range of 70°C to 85°C was supplied through a heat exchange liquid circulation pipe 81 to the heat exchanger for feedstock 80.

[83] After the completion of heat exchange at the heat exchanger for feedstock 80, the mixture's temperature was increased from in a range of 20°C to 30°C to in a range of 40°C to 60°C and then the mixture was supplied to a feedstock supply tank 60. The temperature of a liquid for heat exchange, which completed heat exchanging with the mixture, decreased to a range of 40 °C to 55 °C, and the liquid was transported to an HTC slurry storage tank 73 and supplied back to a heat exchanger for feedstock 80.

[84] The mixture whose temperature rose in the heat exchanger for feedstock 80 was supplied to the feedstock supply tank 60, and the temperature of the mixture was increased to a range of 80°C to 92°C in the feedstock supply tank 60 caused by steam at a high temperature in a range of 140°C to 150°C supplied from a first HTC reactor 10 after the completion of hydrothermal carbonization reaction, and then the mixture was supplied to a second HTC reactor 20. Residual steam at a relative high temperature in a range of 140 °C to 150 °C supplied from the first HTC reactor 10 through a residual steam release valve of the first HTC reactor 41 and release pipe to the feedstock supply tank 60 made a direct contact with the mixture in the feedstock supply tank 60 so that the temperature of the mixture might rise within a short time. To maximize a heat exchange rate between the mixture and residual steam at a relative high temperature in the feedstock supply tank 60, the residual steam stays for 5 minutes to 20 minutes. The residual steam at a relative high temperature in the first HTC reactor 10 is provided the mixture of the feedstock supply tank 60 with heat energy to increase the temperature of the mixture, and then its temperature significantly decreases, which was the time when the mixture was transported to an odor removal facility through release pipe of reactive steam from the feedstock supply tank 61.

[85] During hydrothermal carbonization reaction in the first HTC reactor 10, the temperature of the mixture was increased to 80°C to 92°C at the heat exchanger 80 and the feedstock supply tank 60, and the mixture was supplied to the second HTC reactor. Next, the temperature of the mixture was increased to 140 °C to 150 °C by being supplied with steam at a high temperature in a range of 200°C to 250°C from the first HTC reactor. Afterwards, the temperature of the mixture (feedstock) was increased to 200°C to 230°C by being supplied with steam at a high temperature in a range of 200°C to 250°C from a boiler 50 and hydrothermal carbonization reaction is carried out for 1 hour to 2 hours to convert the mixture into a solid fuel rich in calories.

[86] Steam at a high temperature in a range of 200°C to 230°C in the first HTC reactor after the completion of hydrothermal carbonization reaction was released through a steam release valve of the first HTC reactor 31 and release pipe, and then was supplied to the second HTC reactor 20 through a valve for steam release of an HTC reactor and a boiler, and steam supply valve of the second HTC reactor 34 and supply pipe. 10 minutes to 20 minutes after the supply of steam at a high temperature in a range of 200 °C to 230 °C in the first HTC reactor to the second HTC reactor 20, vapor pressure and temperature in the first and second HTC reactors arrived to an equilibrium state, and at this moment, the internal temperature of two HTC reactors became in a range of 140 °C to 150 °C, and in the process, the energy recovery rate ranged from 25% to 35% of the total needed energy.

[87] Right after the internal temperature of the second HTC reactor became 145°C, steam at a high temperature in a range of 200°C to 250°C was supplied to the second HTC reactor 20 through a valve for steam release of an HTC reactor and a boiler, and steam supply valve of the second HTC reactor 34 and a main valve for steam supply from an HTC reactor. Next, immediately after the internal temperature of the second HTC reactor became in a range of 200 °C to 230 °C, hydrothermal carbonization reaction proceeds for 1 hour to 2 hours. The alternating reaction between the first HTC reactor 10 and the second HTC reactor 20 repeated, and through the alternating reaction, the supplied mixture (feedstock) from the HTC reactors efficiently converted into a solid fuel, a hydro-char rich in calories.

[88] The temperature of the HTC slurry became in a range of 5 100°C to 105°C after steam inside at a high temperature and under a high pressure completely being released after the completion of hydrothermal carbonization reaction at the first HTC reactor 10. This kind of HTC slurry was released to an HTC slurry storage tank 73 through a release valve of an HTC 10 slurry from the first HTC reactor 71 and release pipe. A slight temperature decline occurred during the HTC slurry release to the HTC slurry storage tank 73 so that the temperature remained in a range of 85°C to 95°C while the HTC slurry was stored in the HTC slurry storage tank 73. Heat 15 energy in the HTC slurry storage tank 73 was recovered by a liquid for heat exchange supplied through a heat exchanger 80 and a heat exchange liquid circulation pipe 81, which contributed to a temperature rise of the supplied mixture.

Claims

1. A method of producing a solid fuel with reduced odor by using an energy-saving hydrothermal carbonization reaction, the method comprising:1) pulverizing organic or inorganic waste into particles with a size in a range of 0.1 mm to 1 mm;2) mixing the pulverized organic or inorganic waste with water to prepare a mixture and storing the mixture in a feedstock supply tank;3) supplying the mixture contained in the feedstock supply tank to a first hydrothermal carbonization reactor (HTC reactor) equipped with an agitator and causing an oxygen-blocked reaction within the first HTC reactor at a temperature in a range of 180°C to 230°C under a pressure in a range of 10 to 27 bar for 1 hour to 2 hours by high-temperature steam having a temperature in a range of 200°C to 230°C and a pressure in a range of 15 to 27 bar and being supplied from a boiler;4) supplying the mixture contained in the feedstock supply tank to a second HTC reactor equipped with an agitator and causing an oxygen-blocked reaction in the second HTC reactor at a temperature in a range of 180°C to 230°C under a pressure in a range of 10 to 27 bar for 1 to 2 hours while the reaction proceeds in the first HTC reactor, the reaction being caused by high-temperature steam supplied from the first HTC reactor afterthe completion of step 3);5) increasing an internal temperature of the feedstock supply tank by supplying the high-temperature steam to the feedstock supply tank from the first and second HTC reactors after the completion of step 3) and step 4);6) transporting a hydrothermally carbonized carbide (HTC) slurry into an HTC slurry storage tank; and7) molding and drying the HTC slurry.

2. The method of claim 1, further comprising: increasing the internal temperature of the feedstock supply tank by supplying heat energy of the HTC slurry storage tank that has a temperature in a range of 85°C to 95°C and in which the HTC slurry is contained after the completion of the "6) transporting the HTC slurry into the HTC slurry storage tank" to the feedstock supply tank using a heat exchanger and a heat exchange liquid circulation pipe.

3. The method of claim 2, wherein the internal temperature of the feedstock supply tank is increased to 20°C to 50°C by the increasing of the internal temperature of the feedstock supply tank.

4. The method of claim 3, wherein in the "2) mixing the pulverized organic or inorganic waste with water to prepare amixture", a catalyst is additionally mixed to prepare the mixture.

5. The method of claim 4, wherein the catalyst is selected from the group consisting of an acid-based acid catalyst, a chloride-based acid catalyst, and a combination of the acidbased acid catalyst and the chloride-based acid catalyst.

6. The method of claim 5, wherein the acid-based acid catalyst is H2SO4.

7. The method of claim 5, wherein the chloride-based acid catalyst is HC1, FeCls, or a combination of HC1 and FeCls.

8. The method of claim 7, wherein in the "2) mixing the pulverized organic or inorganic waste with water to prepare a mixture", a catalyst and a ground additive having a size in a range of 0.1 mm to 1 mm are additionally mixed to prepare the mixture.

9. The method of claim 8, wherein raw materials of the organic waste comprise a variety of processed food wastes such as liquor residue, tofu residue, beans, red beans, sweet potatoes, and potatoes; agricultural wastes such as mushroom medium, vegetables, and fruits; livestock wastes such as beefpowder, pork powder, chicken powder, and animal carcasses;marine wastes such as fish, oysters, seaweed, and wakame; and / ordomestic wastes such as sewage sludge, food waste, coffee grounds, and / or garden waste.

510. The method of claim 8, wherein raw materials of inorganic wastes comprise dyeing wastewater sludge, leather wastewater sludge, leather wastewater sludge, paper wastewater sludge, mining wastewater sludge, and / or plating wastewater 10 sludge.

11. The method of claim 10, wherein the organic or inorganic waste is pulverized to have a size in a range of 0.5 mm to 1 mm.1512. A solid fuel produced by any one of the methods of claims 1 to 11.

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