KR102647976B1 - Method for manufacturing high-calorie sludge fuel coal with reduced odor using hybrid hydrothermal carbonization of sewage sludge and sludge fuel coal manufactured by the method - Google Patents

Abstract

The present invention relates to a method for producing high-calorie sludge fuel coal with reduced odor using hybrid hydrothermal carbonization and to high-calorie sludge fuel coal produced by the method, (1) sewage sludge of one type or a mixture of two or more types with a size of 0.05 to 2 mm. pulverizing; (2) pulverizing one or a mixture of two or more lignocellulosic biomass additives to a size of 0.05 to 2 mm; (3) preparing a mixed material by mixing the pulverized sewage sludge and the pulverized lignocellulosic biomass additive with water or steam; (4) Injecting the mixed material into a hydrothermal carbonization reaction tank, blocking oxygen, and maintaining a temperature of 200 to 250 ° C. and a pressure of 20 to 40 bar in a hydrothermal carbonization tank equipped with a stirrer to perform a hydrothermal carbonization reaction for 1 to 2 hours; (5) transferring the carbide produced by the hydrothermal carbonization reaction to a molding dehydrator and molding and dehydrating it; and (6) drying the molded and dehydrated carbide; a method for producing high calorific value sludge fuel coal with reduced odor using hybrid hydrothermal carbonization, and a low calorific value of 3,500 kcal/kg or more and 10% by weight of moisture produced by this method. Hereinafter, it relates to high-calorie sludge fuel coal with sulfur content of 1.0% by weight or less and odor level of 300 or less.

Description

Method for manufacturing high-calorie sludge fuel coal with reduced odor using hybrid hydrothermal carbonization of sewage sludge and sludge fuel coal manufactured by the method}

The present invention relates to a method for producing high-calorie sludge fuel coal with excellent odor reduction effect and high calorific value using a hybrid hydrothermal carbonization reaction from sewage sludge, and a technology related to high-calorie sludge fuel coal produced by the method, which provides energy It is a low-carbon energy technology that can solve supply and demand issues in an integrated manner and contribute to the Korean version of the Green New Deal policy. In addition, it is a solid fuel manufacturing technology and solid fuel technology suitable for responding to the Renewable Portfolio Standard (RPS) for power plants.

Sewage sludge is a representative urban waste, and the way to turn it into energy is to manufacture it into solid fuel. Solid fuel conversion methods include a drying process, carbonization process, torrefaction process, and hydrothermal carbonization process.

Carbonization and torrefaction processes have the disadvantage of essentially removing moisture from the reactant and creating an oxygen-blocked atmosphere by injecting an inert gas (argon, nitrogen, helium, etc.) into the hydrothermal carbonization reaction tank.

In addition, the drying process is a simple and common method that can be performed only with a heat source, but considering that the water content of sewage sludge is about 70 to 90% by weight, the demand for heat energy input during the drying process is high and the heat content as a solid fuel is not high, making it economical. It is not desirable from this point of view. In addition, the problem of sewage sludge odor generated during drying has been constantly pointed out, and various methods are being attempted to solve this problem.

Specifically, the problems with the conventional drying process are as follows.

First, there is a problem that a lot of heat energy is consumed. In other words, in order to produce solid fuel, sewage sludge (moisture content 70-90% by weight) must be dried to a moisture content of 10% by weight or less, and in the case of hot air drying, there is a problem that the temperature needs to be raised up to 400°C.

Second, there is a problem that the caloric value is low, requiring the introduction of caloric supplements. In other words, according to prior art literature, the inherent calorific value of sewage sludge is not high, so there is a problem in that up to 240% of wood must be added compared to sewage sludge to meet the sludge fuel coal standard for power plants, and waste oil must be added up to 10%. There is a problem, and if necessary, high-calorie auxiliaries such as anthracite and oil must be added.

Third, there is a problem with the amount of odor generated. In other words, since sewage sludge is dried as is, the amount of bad odor generated is considerable. Although new drying systems such as vacuum drying have been invented as a means to solve this problem, expensive additional equipment (vacuum equipment, odor suction, deodorization and discharge equipment) is essential. There is a problem.

In this respect, since the hydrothermal carbonization process is a wet process, the primary drying process is not necessary, so sewage sludge can be used directly for reaction without pretreatment, and it has a higher calorific value than solid fuel produced from the existing drying process and has a high odor reduction effect. It's technology.

Republic of Korea Patent Publication No. 10-2037447 (Sewage sludge vacuum drying fuel system) Republic of Korea Patent Publication No. 10-1584621 (Mixing drying device for converting sewage sludge into fuel and manufacturing method of sewage sludge fuel coal)

The present invention is a method of producing high-calorie sludge fuel coal with reduced odor using hybrid hydrothermal carbonization, which complements and improves problems arising from the conventional drying process technology that has been commonly used in the production of sewage sludge fuel coal, and high-calorie sludge produced by the method. As it relates to fuel coal, it has the following problems to be solved.

First, in order to produce solid fuel through a drying process according to the prior art, sewage sludge (moisture content 70-90% by weight) must be dried to a moisture content of 10% by weight or less, and in the case of hot air drying, heating up to a maximum of 400°C is required, so heat energy is required. There is a problem that a large amount of is required, and the purpose of the present invention is to provide a method for producing high-calorie sludge fuel coal with reduced odor using hybrid hydrothermal carbonization and high-calorie sludge fuel coal that solves this problem.

Second, when producing solid fuel through a drying process according to the prior art, the calorific value of sewage sludge itself is not high, so wood must be added up to 240% as a caloric supplement compared to sewage sludge to meet the sludge fuel coal standard for power plants, and waste oil There is a problem that up to 10% must be added, and if necessary, high-calorie auxiliaries such as anthracite coal and oil must also be added. The present invention solves this problem by manufacturing high-calorie sludge fuel coal with reduced odor using hybrid hydrothermal carbonization. The purpose is to provide a method and high-calorie sludge fuel coal.

Third, in order to produce solid fuel using the drying process according to the prior art, there is a problem in that sewage sludge is dried as is, resulting in a significant amount of odor, and new drying systems such as vacuum drying adopted as a means of solving this problem are expensive and expensive. There is a problem that additional equipment (vacuum equipment, odor suction and discharge equipment) is essentially required, and the present invention provides a method for producing high-calorie sludge fuel coal with reduced odor using hybrid hydrothermal carbonization, which solves this problem, and high-calorie sludge fuel coal. It is to have a purpose.

In order to achieve the above object, the method for producing high-calorie sludge fuel coal with reduced odor achieved through the present invention includes the steps of (1) pulverizing sewage sludge; (2) grinding the lignocellulosic biomass additive; (3) preparing a mixed material by mixing the pulverized sewage sludge and the pulverized lignocellulosic biomass additive with water or steam; (4) Injecting the mixed materials into a hydrothermal carbonization reaction tank, blocking oxygen, and performing a hydrothermal carbonization reaction in a hydrothermal carbonization reaction tank equipped with a stirrer; (5) transferring the carbide produced by the hydrothermal carbonization reaction to a molding dehydrator and molding and dehydrating it; and (6) drying the molded and dehydrated carbide; a method for producing high calorific value sludge fuel coal with reduced odor using hybrid hydrothermal carbonization, and a low calorific value of 3,500 kcal/kg or more and 10% by weight of moisture produced by this method. Hereinafter, it relates to high-calorie sludge fuel coal with sulfur content of 1.0% by weight or less and odor level of 300 or less.

Here, the sewage sludge can be used as one type or by mixing two or more different types of sewage sludge. It is preferable to pulverize the sewage sludge to a size of 0.05 to 2 mm, and to pulverize the sewage sludge to a size of 0.1 to 1 mm. It is more preferable, and it is most preferable to grind it to a size of 0.1 to 0.5 mm.

In addition, the lignocellulosic biomass additive uses lignocellulosic biomass such as sawdust and waste wood, and is preferably pulverized to a size of 0.05 to 2 mm, more preferably pulverized to a size of 0.1 to 1 mm, and 0.1 to 0.5 mm. It is most desirable to crush it to a size of .

In addition, the sewage sludge is preferably mixed with 1 to 9 times the weight of the lignocellulosic biomass additive (lignocellulosic biomass additive: sewage sludge = 1: 1 to 9 by weight), and the water or steam is mixed with pulverized sewage. It is preferable to mix sludge and pulverized lignocellulosic biomass additives in an amount of 0.5 to 2 times the weight (sewage sludge and lignocellulosic biomass additives: water or steam = 1:0.5 to 2 weight).

In addition, the mixed material obtained in the step of producing a mixed material by mixing the pulverized sewage sludge and the pulverized lignocellulosic biomass additive with water or steam is introduced into a hydrothermal carbonization reaction tank, oxygen is blocked, and a stirrer is installed. In the process of hydrothermal carbonization in the hydrothermal carbonization reaction tank, water or steam is supplied considering the capacity of the hydrothermal carbonization tank and the process moisture content, and it is desirable to react so that ionicity is maximized under subcritical water conditions. The hydrothermal carbonization reaction step is carried out at temperature. It is preferable to carry out the hydrothermal carbonization reaction for 1 to 2 hours by maintaining the temperature at 200 to 250 ℃ and the pressure at 20 to 40 bar, and it is more preferable to carry out the hydrothermal carbonization reaction at 210 to 230 ℃ and the pressure at 25 to 35 bar for 1 to 2 hours.

In addition, the water recovered in the molding and dehydration steps in the molding dehydrator is transferred to a water purification device, purified, and then transferred to a water tank for reuse, which has the effect of greatly reducing water usage.

In addition, in the step of preparing the mixed material, water or steam is mixed with the pulverized sewage sludge and the pulverized lignocellulosic biomass additive. In addition, a catalyst may be additionally added and mixed.

Here, the catalyst is selected from the group consisting of an acid catalyst, a base catalyst, an inorganic metal catalyst, or a mixture thereof depending on the characteristics of the raw material. The acid catalyst is hydrochloric acid (HCl). ), sulfuric acid (H ₂ SO ₄ ), and phosphoric acid (H ₃ PO ₄ ) are preferred, and the base catalyst is preferably a strong base such as sodium hydroxide (NaOH) and potassium hydroxide (KOH), and an inorganic metal catalyst. It is preferable that it is an iron type such as iron chloride (FeCl ₃ , FeCl ₂ ), ferric oxide (Fe ₂ O ₃ ), or a mixture thereof.

Meanwhile, the present invention relates to high-calorie sludge fuel coal with reduced odor produced by the method for producing high-calorie sludge fuel coal with reduced odor using hybrid hydrothermal carbonization described above.

The low calorific value of solid fuel produced through the drying process of sewage sludge according to the prior art was only 3,000 kcal/kg on average, and a large amount of bad odor was generated during the drying process. Not only was it impossible to perform the drying process due to the foul odor generated during the sewage sludge drying process according to the prior art, but sawdust was used to increase the low calorific value of the solid fuel produced by the sewage sludge drying process according to the prior art. Even when mixed, the amount was only about 3,500 kcal/kg, so the drying process of sewage sludge according to the prior art was impossible.

In comparison, the high calorific value sludge fuel coal with reduced odor of the present invention meets the conditions of a low calorific value of 3,500 kcal/kg or more, moisture 10% by weight or less, and sulfur 1.0% by weight or less according to the quality standard for sewage sludge fuel coal for power generation (GR M 9018-2019). Since it satisfies the condition of an odor level of 300 or less according to the National Institute of Environmental Research Notice No. 2019-17 (Odor Process Test Standard), the present invention provides a high-calorie sludge fuel coal with reduced odor as a desirable one.

In addition, the more preferred high-calorie sludge fuel coal with reduced odor of the present invention satisfies the conditions of low-level calorific value of 3,500 to 7,000 kcal/kg, moisture 1 to 10% by weight, sulfur 0.05 to 1.0% by weight, and odor degree of 80 to 300.

Furthermore, the most preferred high-calorific value sludge fuel coal with reduced odor of the present invention satisfies the conditions of low calorific value of 4,500 to 7,000 kcal/kg, moisture of 1 to 7% by weight, sulfur of 0.05 to 0.7% by weight, and odor degree of 80 to 250.

The present invention is a method of producing high-calorie sludge fuel coal with reduced odor using hybrid hydrothermal carbonization, which complements and improves problems arising from the conventional drying process technology that has been generally used in the production of sludge fuel coal, and high-calorie sludge fuel coal manufactured by the method. As it relates to, it has the following effects.

First, in order to produce solid fuel through a drying process according to the prior art, sewage sludge (moisture content 70-90% by weight) must be dried to a moisture content of 10% by weight or less, and in the case of hot air drying, heating up to a maximum of 400°C is required, so heat energy is required. There is a problem that a large amount of is required, and the present invention shows a remarkable effect of providing a high-calorie sludge fuel coal and a method of producing high-calorie sludge fuel coal with reduced odor using hybrid hydrothermal carbonization that solves this problem.

Second, when producing solid fuel through a drying process according to the prior art, the calorific value of sewage sludge itself is not high, so wood must be added up to 240% as a caloric supplement compared to sewage sludge to meet the sludge fuel coal standard for power plants, and waste oil There is a problem in that up to 10% must be added, and if necessary, high-calorie auxiliaries such as anthracite coal and oil must also be added. The present invention is a method of producing high-calorie sludge fuel coal with reduced odor using hybrid hydrothermal carbonization, which solves this problem. And it shows a remarkable effect of providing high-calorie sludge fuel coal.

Third, in order to produce solid fuel using the drying process according to the prior art, there is a problem in that sewage sludge is dried as is, resulting in a very large amount of odor, and new drying systems such as vacuum drying adopted as a means to solve this problem are expensive and expensive. There is a problem that additional equipment (vacuum equipment, odor intake and discharge equipment) is essentially required, and the present invention provides a method for producing high-calorie sludge fuel coal with reduced odor using hybrid hydrothermal carbonization, which solves these problems, and provides high-calorie sludge fuel coal. It shows a remarkable effect.

Fourth, when mixing sewage sludge and additives (sawdust, waste wood) to produce sludge fuel coal through a drying process according to the prior art, the homogeneity is low, so there are problems with separation of properties during combustion, low ignition point of sludge fuel coal, and low combustion. Although there may be problems with temperature and combustion faster than coal, the present invention maintains the homogeneity of the product and the stability of combustion through the chemical reaction of hydrothermal carbonization even when sewage sludge and additives (lignocellulosic biomass such as sawdust and waste wood) are mixed. It has an improving effect.

Fifth, the heat energy consumed in the hybrid hydrothermal carbonization process of the present invention is 220 kcal/kg, whereas the heat energy consumed in the conventional drying process is 640 kcal/kg, so the heat energy consumed in the present invention is less than that consumed in the conventional drying process. Since it is at the level of 33% of thermal energy, it has a remarkable effect of very high energy efficiency. Furthermore, since the present invention proceeds quickly within 1 to 2 hours at a low temperature of 200 to 250 ° C, it has an excellent effect in terms of economic efficiency of the process.

Sixth, unlike the physical treatment of drying sewage sludge by mixing wood in the drying process according to the prior art, the hydrothermal carbonization of the present invention is a chemical treatment that lowers the ratio of hydrogen and oxygen contained in the raw materials and increases the fixed carbon in sawdust. Even if a small amount is added, the calorific value is high (lower calorific value of 5,000 kcal/kg or more), so the addition of caloric auxiliaries is unnecessary, and the odor-causing effect is also very excellent by removing odor-causing substances through this hydrothermal carbonization (chemical treatment). .

Figure 1 is a configuration diagram of an apparatus for producing high-calorie and odor-reducing sludge fuel coal using hybrid hydrothermal carbonization of sewage sludge according to an embodiment of the present invention.
Figure 2 is a graph comparing the high calorific value of sludge fuel coal that has gone through a drying process (Comparative Example 1) and sludge fuel coal that has gone through a hydrothermal carbonization process (Example 1) with respect to raw sewage sludge, a mixture of sewage sludge and sawdust.
Figure 3 is a table comparing the main items of the sewage sludge fuel coal quality standard for power generation (GR M 9018-2019) and the characteristics of sludge fuel coal (Example 1) that underwent a hydrothermal carbonization process.

The present invention provides a technology that can produce sludge fuel coal with high heat and excellent odor reduction effects from sewage sludge, which was impossible to produce through the drying process according to the prior art, through hybrid hydrothermal carbonization.

In the present invention, sewage sludge is a residue remaining from sewage treatment and includes organic waste generated from primary physical treatment.

In the present invention, hydrothermal carbonization means that ionicity is maximized and dielectric constant is reduced when in the form of steam (high temperature and medium pressure) or water (high temperature and high pressure) at a pressure and temperature below the supercritical condition of water (374°C, 221.1 bar). Using this property, hydrolysis and decarboxylation of organic substances are applied by applying hydrolysis, thereby reducing the amount of hydrogen and oxygen and increasing the amount of carbon, thereby increasing the amount of fixed carbon, thereby reducing the calorific value of the final solid fuel produced. It is a reaction that can reduce bad odor by increasing and reducing odor-causing substances. The temperature and pressure of hydrothermal carbonization are 200-250°C and 20-40 bar, and wet carbonization is performed over a process time of 1 to 2 hours in a container that can withstand pressure above that.

In addition, sludge fuel coal with high calorific value and odor reduction using hybrid hydrothermal carbonization of sewage sludge meets the main quality standards for sewage sludge fuel coal for power generation (GR M 9018-2019), that is, low calorific value of 3,500 kcal/kg or more, moisture 10% by weight or less, and sulfur 1.0 weight. It is characterized as satisfying the conditions of % or less and odor level of 300 or less.

In order to achieve the above object, the method for producing high-calorie sludge fuel coal with reduced odor achieved through the present invention includes the steps of (1) pulverizing one type or a mixture of two or more types of sewage sludge to a size of 0.05 to 2 mm; (2) pulverizing one or a mixture of two or more lignocellulosic biomass additives to a size of 0.05 to 2 mm; (3) preparing a mixed material by mixing the pulverized sewage sludge and the pulverized lignocellulosic biomass additive with water or steam; (4) Injecting the mixed material into a hydrothermal carbonization reaction tank, blocking oxygen, and maintaining a temperature of 200 to 250 ° C. and a pressure of 20 to 40 bar in a hydrothermal carbonization tank equipped with a stirrer to perform a hydrothermal carbonization reaction for 1 to 2 hours; (5) transferring the carbide produced by the hydrothermal carbonization reaction to a molding dehydrator and molding and dehydrating it; and (6) drying the molded and dehydrated carbide; a method for producing high calorific value sludge fuel coal with reduced odor using hybrid hydrothermal carbonization, and a low calorific value of 3,500 kcal/kg or more and 10% by weight of moisture produced by this method. Hereinafter, it relates to high-calorie sludge fuel coal with sulfur content of 1.0% by weight or less and odor level of 300 or less.

Here, the sewage sludge can be used as one type or by mixing two or more different types of sewage sludge. It is preferable to pulverize the sewage sludge to a size of 0.05 to 2 mm, and to pulverize the sewage sludge to a size of 0.1 to 1 mm. It is more preferable, and it is most preferable to grind it to a size of 0.1 to 0.5 mm.

In addition, the lignocellulosic biomass additive uses lignocellulosic biomass such as sawdust and waste wood, and is preferably pulverized to a size of 0.05 to 2 mm, more preferably pulverized to a size of 0.1 to 1 mm, and 0.1 to 0.5 mm. It is most desirable to crush it to a size of .

In addition, the sewage sludge is preferably mixed with 1 to 9 times the weight of the lignocellulosic biomass additive (lignocellulosic biomass additive: sewage sludge = 1: 1 to 9 by weight), and the water or steam is mixed with pulverized sewage. It is preferable to mix sludge and pulverized lignocellulosic biomass additives in an amount of 0.5 to 2 times the weight (sewage sludge and lignocellulosic biomass additives: water or steam = 1:0.5 to 2 weight).

In addition, the mixed material obtained in the step of producing a mixed material by mixing the pulverized sewage sludge and the pulverized lignocellulosic biomass additive with water or steam is introduced into a hydrothermal carbonization reaction tank, oxygen is blocked, and a stirrer is installed. In the process of hydrothermal carbonization in the hydrothermal carbonization reaction tank, water or steam is supplied considering the capacity of the hydrothermal carbonization tank and the process moisture content, and it is desirable to react so that ionicity is maximized under subcritical water conditions. The hydrothermal carbonization reaction step is carried out at temperature. It is more preferable to carry out the hydrothermal carbonization reaction by maintaining the temperature at 210 to 230°C and the pressure at 25 to 35 bar for 1 to 2 hours.

In addition, the water recovered in the molding and dehydration steps in the molding dehydrator is transferred to a water purification device, purified, and then transferred to a water tank for reuse, which has the effect of greatly reducing water usage.

In addition, in the step of preparing the mixed material, water or steam is mixed with the pulverized sewage sludge and the pulverized lignocellulosic biomass additive. In addition, a catalyst may be additionally added and mixed.

Here, the catalyst is selected from the group consisting of an acid catalyst, a base catalyst, an inorganic metal catalyst, or a mixture thereof depending on the characteristics of the raw material. The acid catalyst is hydrochloric acid (HCl). ), sulfuric acid (H ₂ SO ₄ ), and phosphoric acid (H ₃ PO ₄ ) are preferred, and the base catalyst is preferably a strong base such as sodium hydroxide (NaOH) and potassium hydroxide (KOH), and an inorganic metal catalyst. It is preferable that it is an iron type such as iron chloride (FeCl ₃ , FeCl ₂ ), iron oxide (Fe ₂ O ₃ ), or a mixture thereof.

Meanwhile, the present invention relates to high-calorie sludge fuel coal with reduced odor produced by the method for producing high-calorie sludge fuel coal with reduced odor using hybrid hydrothermal carbonization described above.

The low calorific value of solid fuel produced through the drying process of sewage sludge according to the prior art was only 3,000 kcal/kg on average, and a large amount of bad odor was generated during the drying process. Not only was it impossible to perform the drying process due to the foul odor generated during the sewage sludge drying process according to the prior art, but sawdust was used to increase the low calorific value of the solid fuel produced by the sewage sludge drying process according to the prior art. Even when mixed, the amount was only about 3,500 kcal/kg, so the drying process of sewage sludge according to the prior art was impossible to perform.

In comparison, the high calorific value sludge fuel coal with reduced odor of the present invention meets the conditions of a low calorific value of 3,500 kcal/kg or more, moisture 10% by weight or less, and sulfur 1.0% by weight or less according to the quality standard for sewage sludge fuel coal for power generation (GR M 9018-2019). Since it satisfies the condition of an odor level of 300 or less according to the National Institute of Environmental Research Notice No. 2019-17 (Odor Process Test Standard), the present invention provides a high-calorie sludge fuel coal with reduced odor as a desirable one.

In addition, the more preferred high-calorie sludge fuel coal with reduced odor of the present invention satisfies the conditions of low-level calorific value of 3,500 to 7,000 kcal/kg, moisture 1 to 10% by weight, sulfur 0.05 to 1.0% by weight, and odor degree of 80 to 300.

Furthermore, the most preferred high-calorific value sludge fuel coal with reduced odor of the present invention satisfies the conditions of low calorific value of 4,500 to 7,000 kcal/kg, moisture of 1 to 7% by weight, sulfur of 0.05 to 0.7% by weight, and odor degree of 80 to 250.

An apparatus for performing a method of producing high-calorie sludge fuel coal with reduced odor using hybrid hydrothermal carbonization of sewage sludge according to the present invention will be described with reference to FIG. 1.

The device according to the present invention includes a raw material supply device (15) for mixing and supplying raw materials such as sewage sludge, sawdust, and waste wood at a certain ratio; A water tank (30) for supplying water or steam; A hydrothermal carbonization reaction tank (45) in which a hydrothermal carbonization process is performed to increase the calorific value of the raw materials and remove odor-causing substances while mixing and stirring the supplied water and the raw materials; A forming dehydrator (60) that dehydrates the carbide generated in the hydrothermal carbonization process of the hydrothermal carbonization reaction tank (45) and performs a molding process to make solid fuel in the form of pellets, etc.; It includes a dryer 90 that removes moisture remaining on the surface of the solid fuel in the form of pellets.

In addition, it further includes a water purification device 75 that purifies the water output from the molded dehydrator 60 and feeds it back to the water tank 30. The hydrothermal carbonization tank (45) is equipped with a stirrer to ensure good mixing. The hydrothermal carbonization tank (45) is made of a pressure vessel that can withstand a maximum of 40 bar and 280°C, and gates that can be opened and closed are installed at the top and bottom. Enables injection of raw materials supplied to the top.

In addition, for the purpose of increasing production, two or more hydrothermal carbonization reactors (45) can be placed and operated, and after the hydrothermal carbonization process is completed, the remaining waste heat can be connected in a way that can be utilized in other hydrothermal carbonization reactors (45). .

The lower part of the hydrothermal carbonization reaction tank (45) allows the reactants to go to the molding dehydrator (60), and the water tank (30) is connected to the hydrothermal carbonization reaction tank (45), which will be the core of the hydrothermal carbonization reaction, so that the necessary water can be used for sawdust and waste wood. It is supplied in 0.5 to 2 times the amount by weight compared to raw materials such as

The molding dehydrator 60 uses a filter press method, and the wastewater is treated and purified by the activated sludge method or reverse osmosis method in the water purification treatment device 75 and then sent to the water tank 30 for recycling.

The molded dehydrator 60 and the water purification device 75 can be implemented in different ways as needed. The reactant molded through the molding dehydrator 60 is dried through low-temperature drying in the dryer 90, is produced as the final sludge fuel coal 100, and is then transferred to a storage tank. All of these processes are designed based on the batch production method, but the supplied fuel is standardized and processes such as opening and closing the gate are automated, so it can be configured as a continuous operation method.

Water is supplied considering the capacity and total water content of the hydrothermal carbonization reaction tank 45, and ionicity is maximized under subcritical water conditions. During the process, the reactants (sewage sludge, sawdust, waste wood, and water) are stirred to mix well. The manufactured sludge fuel coal can be naturally dried or hot air dried as needed. Since the moisture in the molecular structure has been removed, it can be sufficiently dried in a short period of time by drying at low temperature below 100℃.

Raw materials (sewage sludge, sawdust, and waste wood) are supplied at 0.5 to 2 times the amount of water based on weight ratio. The ratio between raw materials (sewage sludge, sawdust, and waste wood) can be changed as needed, and sewage sludge is supplied at 1 to 9 times the amount of sawdust by weight. Additionally, lignocellulosic waste biomass (waste wood, etc.) can be used. One type of sewage sludge can be used alone, or two or more different types of sludge can be mixed.

[Example 1]

Sludge fuel coal was manufactured through hybrid hydrothermal carbonization of sewage sludge. Sewage sludge and sawdust were mixed in equal proportions and sludge fuel coal was produced through hydrothermal carbonization in the following manner.

Sewage sludge and sawdust were mixed at a certain weight ratio, and water was supplied and mixed by weight to make it 0.5 to 2 times the amount of the mixture. This was supplied to a 1L hydrothermal carbonization reactor (45) and heated to 200 to 250°C for 1 to 2 hours. Hydrothermal carbonization was performed.

After hydrothermal carbonization, the product was vacuum separated using Watman #1 filter paper and a pressure flask for solid-liquid separation, and the solid was dried in a forced circulation dryer (90) at 90°C and then measured through a Bomb Calorimeter (Parr 6200 Isoperibol Oxygen Bomb Calorimeter). High-level calorific value was measured.

[Comparative Example 1]

Sludge fuel coal was manufactured by mixing sewage sludge and sawdust at a certain weight ratio and using a drying process according to the prior art in the following manner.

Sewage sludge and sawdust were mixed and the mixture was dried at 90°C in a forced circulation dryer (90) to produce sludge fuel coal, and the higher calorific value was measured using a Bomb Calorimeter (Parr 6200 Isoperibol Oxygen Bomb Calorimeter).

The higher calorific values for raw sewage sludge/Comparative Example 1 (sludge fuel coal manufactured through a drying process)/Example 1 (sludge fuel coal manufactured through a hydrothermal carbonization process) are shown in Figure 2.

Referring to Figure 2, sludge fuel coal obtained by mixing raw sewage sludge, sewage sludge and sawdust at a certain weight ratio and subjecting the mixture to a drying process (Comparative Example 1), and sludge fuel coal subjected to a hydrothermal carbonization process (Example 1). The high calorific value of was measured to be 2,830 kcal/kg, 3,840 kcal/kg, and 5,480 kcal/kg, respectively. These results show that the calorific value of sludge fuel coal (Example 1) that has gone through the hydrothermal carbonization process is higher than that of sludge fuel coal that has gone through the drying process (comparison). It can be seen that the calorific value has increased by about 43% compared to Example 1).

In order to compare the low calorific value, ash, moisture, and sulfur content of Example 1 (sludge fuel coal produced by the hydrothermal carbonization process) with the sewage sludge fuel coal quality standard for power generation (GR M 9018-2019), Ministry of Environment Notice No. 2020-219 According to the standard (solid fuel product quality test and analysis method), thermogravimetric analyzer (TGA-701 Proximate Analyzer), sulfur analyzer (SC-832DR Sulfur Analyzer), elemental analyzer (SC-832DR Sulfur Analyzer), calorific value analyzer (AC600 Semi- Industrial analysis, elemental analysis, and high and low calorific values were measured using analytical equipment such as an auto Calorimeter.

In addition, the odor of Example 1 (sludge fuel coal produced by the hydrothermal carbonization process) was analyzed by gas chromatography (GC2010 Plus GC) and high-performance liquid chromatography ( The concentration and complex odor level of 15 major odor-causing substances were measured using equipment such as LC-20A Series HPLC.

The results of the measurement as above are shown in Figure 3.

Referring to FIG. 3, as mentioned in the effect of the invention, the method for producing high-calorie sludge fuel coal with reduced odor using hybrid hydrothermal carbonization of sewage sludge according to the present invention, and the high-calorie sludge fuel coal produced by the method have a low With a calorific value of 5,170 kcal/kg and a combined odor level of 144, it not only has an excellent high calorific value and odor reduction effect, but also contains 13.3% by weight of ash, 2.4% by weight of moisture, and 0.3% of sulfur, so all feedstock is sewage sludge for power generation. It was confirmed that it was significantly superior to the values specified in the fuel coal quality standard (GR M 9018-2019).

15: Raw material supplier
30: Water tank
45: Hydrothermal carbonization reaction tank
60: Molding dehydrator
75: Water treatment device
90: dryer
100: Sludge fuel coal

Claims (15)

(1) pulverizing one type or two or more types of sewage sludge into a size of 0.1 to 0.5 mm;
(2) pulverizing one or a mixture of two or more lignocellulosic biomass additives to a size of 0.1 to 0.5 mm;
(3) Mix the pulverized sewage sludge with 1 to 9 times the weight of the pulverized lignocellulosic biomass additive, and mix water or steam with 0.5 to 2 times the weight of the pulverized sewage sludge and the pulverized lignocellulosic biomass additive. The mixed material is prepared by mixing hydrochloric acid (HCl), sodium hydroxide (NaOH), potassium hydroxide (KOH), ferrous chloride (FeCl ₂ ), or ferric oxide (Fe ₂ O ₃ ) as a catalyst. step;
(4) Injecting the mixed materials into a hydrothermal carbonization reaction tank, blocking oxygen, and maintaining a temperature of 210 to 230 ° C. and a pressure of 25 to 35 bar in a hydrothermal carbonization reaction tank equipped with a stirrer to perform a hydrothermal carbonization reaction for more than 1 hour to 2 hours;
(5) transferring the carbide produced by the hydrothermal carbonization reaction to a molding dehydrator and molding and dehydrating it;
(6) the water recovered in the molding and dehydration step in the molding dehydrator is transferred to a water purification device, purified, and then transferred to a water tank for reuse; and
(7) drying the molded and dehydrated carbide; using hybrid hydrothermal carbonization including a low heating value of 4,500 to 7,000 kcal/kg, moisture of 1 to 7% by weight, sulfur 0.05 to 0.7% by weight, and odor level of 80 to 80. 250 Method for manufacturing high-calorie sludge fuel coal with reduced odor.
delete delete delete delete delete delete delete delete delete delete delete High calorific value sludge fuel coal with reduced odor produced by the manufacturing method of claim 1 is characterized by a low calorific value of 4,500 to 7,000 kcal/kg, moisture of 1 to 7% by weight, sulfur of 0.05 to 0.7% by weight, and odor degree of 80 to 250. High-calorie sludge fuel with reduced odor.
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