Exhaust gas treatment system

Abstract

This exhaust gas treatment system utilizes biomass combustion gas to efficiently remove harmful substances from exhaust gases, thereby reducing energy consumption and lowering environmental impact. [Solution] The system includes a biomass combustion chamber 2 for burning biomass, a combustion gas path 3 for releasing combustion gas G1, an exhaust gas path 4 for releasing exhaust gas G2 discharged from industrial facilities, a filter unit 5 positioned on the exhaust gas path 4 for adsorbing and decomposing harmful substances, a first branch 6 for supplying combustion gas G1 upstream of the filter unit 5, and a second branch 7 for supplying combustion gas G1 to the filter unit 5. Furthermore, a heat exchanger 8 for recovering heat from the combustion gas G1 is positioned downstream of the second branch 7 of the combustion gas path 3, and an ash recovery device 9 for recovering ash generated after biomass combustion is positioned at or immediately after the connection point between the combustion gas path 3 and the biomass combustion chamber 2.

Description

Technical Field

[0005]

[0001] The present invention relates to an exhaust gas treatment system that treats exhaust gas discharged from industrial facilities by using combustion gas of biomass.

Background Art

[0002] In modern industrial activities, a large amount of exhaust gas is discharged from industrial facilities such as factories and power plants. These exhaust gases contain harmful substances such as carbon dioxide (CO2), nitrogen oxides (NOx), sulfur oxides (SOx), and volatile organic compounds (VOC), which not only cause global warming and acid rain, but also cause air pollution and have a serious impact on human health and the ecosystem. Therefore, the development of technologies for efficiently removing these harmful substances is required.

[0003] Conventional exhaust gas treatment technologies include an electrostatic precipitator (see, for example, Patent Document 1 and Non-Patent Document 1), a bag filter (see, for example, Patent Document 1 and Non-Patent Document 1), a wet scrubber (see Patent Document 2), a catalytic reduction technology: SCR (see, for example, Patent Document 3), an adsorption filter (see, for example, Patent Document 4), and the like.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Non-Patent Documents

[0005] <00−00032>

Non-Patent Document 1

[0006] However, while conventional technologies excel at performing processing tailored to their specific purposes, they have the following challenges: (1) High operating costs In particular, exhaust gas treatment systems that utilize catalysts have the disadvantage of high costs associated with catalyst replacement and maintenance. (2) High energy consumption High-temperature treatment may be required during the exhaust gas treatment process, which increases energy consumption. (3) Generation of secondary waste After exhaust gas treatment, it may be necessary to dispose of filter residue and treated water, which is insufficient for reducing environmental impact. (4) Insufficient reduction of CO2 Many exhaust gas treatment technologies focus on removing harmful gases such as NOx and SOx, and do not adequately address the reduction of CO2 emissions.

[0007] On the other hand, biomass is attracting attention as a renewable energy source and has the characteristic of having a lower environmental impact compared to fossil fuels. In particular, by utilizing biomass derived from wood pellets, agricultural waste, and municipal solid waste, sustainable energy supply becomes possible. The energy obtained from burning biomass can be used not only for heat recovery and power generation, but also to improve the efficiency of exhaust gas treatment processes by utilizing the combustion gases.

[0008] Therefore, there is a need to develop new exhaust gas treatment technologies that effectively utilize biomass while solving the problems of conventional exhaust gas treatment technologies. This invention has been made in view of the above circumstances, and its main objective is to provide an exhaust gas treatment system that uses biomass combustion gas to solve the following specific problems. (1) Efficiently remove harmful substances (NOx, SOx, VOCs, etc.) from exhaust gas. (2) To reduce energy consumption in exhaust gas treatment. (3) Minimize the generation of secondary waste. (4) To reduce CO2 emissions and achieve carbon neutrality. [Means for solving the problem]

[0009] To achieve the above objectives, the exhaust gas treatment system according to the present invention is A combustion chamber for burning biomass, A combustion gas path for releasing combustion gases generated in the combustion chamber, An exhaust gas path that releases exhaust gases emitted from industrial facilities, A filter unit is placed on the exhaust gas path and adsorbs harmful substances (NOx, SOx, VOCs, etc.) in the exhaust gas, and decomposes the adsorbed harmful substances by a catalytic reaction. A first branch path that branches off from the combustion gas path and supplies the combustion gas to the upstream side of the exhaust gas path from the filter unit, A second branch path that branches off from the aforementioned combustion gas path and supplies the combustion gas to the filter unit, Downstream from the second branch of the combustion gas path, there is a heat exchanger that recovers heat from the combustion gas flowing through the combustion gas path, An ash recovery device is positioned at or immediately after the connection point between the combustion gas path and the combustion chamber, and recovers ash generated after biomass combustion. It is characterized by possessing the following features.

[0010] Therefore, according to the present invention, since the filter unit disposed on the exhaust gas path has both an adsorption function and a catalytic decomposition function, harmful substances such as NOx, SOx, and VOC in the exhaust gas can be collected by the adsorption filter and decomposed by chemical reaction by the catalytic filter. Furthermore, by utilizing the first branch path and the second branch path from the combustion gas path, CO and H2 contained in the combustion gas can be supplied to the catalytic filter, so that the reduction reaction can be promoted and the decomposition efficiency can be improved. For this reason, compared with the conventional exhaust gas treatment device, harmful substances can be removed more effectively, and the environmental load can be reduced.

[0011] Also, according to the present invention, by utilizing the biomass combustion gas, the reaction of the catalytic filter can be promoted, so that while suppressing additional heating energy for maintaining a high temperature like the conventional SCR technology, it is possible to decompose harmful substances. Moreover, by installing a heat exchanger on the downstream side of the second branch path of the combustion gas path, the thermal energy of the combustion gas can be recovered and reused for the energy supply of factories and power plants. For this reason, it is possible to reduce the energy consumption of exhaust gas treatment and suppress the operation cost of the system.

[0012] Furthermore, according to the present invention, since the ash generated in the biomass combustion chamber can be recovered, by reusing the ash generated in the exhaust gas treatment system as fertilizer or building materials, waste can be reduced. Also, by combining the regeneration technology of the adsorption filter, the frequency of filter replacement can be reduced, and the amount of filter waste can be minimized. For this reason, it is possible to suppress the generation of secondary waste associated with exhaust gas treatment and realize a sustainable exhaust gas treatment system.

[0013] Furthermore, according to the present invention, by burning biomass fuel, it is possible to reduce the amount of CO2 emissions compared to the exhaust gas treatment technology using conventional fossil fuels. Also, by performing energy recovery using a heat exchanger simultaneously with exhaust gas treatment, the energy efficiency of the entire system can be improved, and additional energy consumption can be minimized. Therefore, it becomes possible to reduce the amount of CO2 emissions associated with exhaust gas treatment and contribute to the realization of carbon neutrality.

[0014] Here, the filter unit an adsorption filter that collects harmful substances contained in the exhaust gas by physical adsorption, and a catalyst filter that decomposes and removes the harmful substances collected by the adsorption filter by a catalytic reaction (oxidation / reduction reaction) to render them harmless. The second branch may supply the combustion gas to the catalyst filter.

[0015] By adopting such a configuration, harmful substances in the exhaust gas can be efficiently collected by the adsorption filter, and the catalytic reaction can be promoted by the combustion gas supplied to the catalyst filter. As a result, the decomposition efficiency of harmful substances can be improved, additional energy consumption in the exhaust gas treatment process can be suppressed, and the operation cost of the entire system can be reduced. In addition, carbon monoxide (CO) and hydrogen (H2) contained in the combustion gas supplied to the catalyst filter promote the reduction reaction and contribute to maintaining the activity of the catalyst. As a result, the deterioration of the catalyst can be suppressed, stable operation over a long period is possible, and operation cost reduction can be achieved by reducing the catalyst replacement frequency. Furthermore, as the decomposition of harmful substances by the catalyst filter progresses, the burden on the adsorption filter is reduced. As a result, the regeneration of the adsorption filter is promoted, long-term use is possible, and the filter replacement frequency can be suppressed. As a result, the generation of secondary waste can be minimized, leading to a reduction in environmental load.

[0016] It is preferable that the first branch and the second branch each be provided with a flow rate adjustment means for adjusting the amount of combustion gas supplied (the flow rate adjustment means provided in the first branch shall be referred to as the first flow rate adjustment means, and the flow rate adjustment means provided in the second branch shall be referred to as the second flow rate adjustment means). The first flow rate adjustment means allows for adjustment of the amount of combustion gas supplied to the exhaust gas path. This enables control of the exhaust gas temperature upstream of the filter unit and optimizes the performance of the adsorption filter. Furthermore, by adjusting the amount of combustion gas supplied in accordance with fluctuations in the exhaust gas flow rate, the load on the filter unit can be equalized, achieving stable exhaust gas treatment. Furthermore, the second flow rate adjustment means allows for adjustment of the amount of combustion gas supplied to the catalytic filter. This optimizes the temperature and the progress of the reduction reaction within the catalytic filter, improving the efficiency of decomposition of harmful substances while maintaining the activity of the catalyst. In addition, by appropriately controlling the amount of combustion gas supplied, catalyst degradation is suppressed, enabling stable operation over a long period, and the frequency of catalyst replacement is reduced, thereby lowering operating costs.

[0017] Furthermore, when the adsorption filter that adsorbs harmful substances from exhaust gas is made of activated carbon, zeolite, or silica gel, the temperature required to obtain the adsorption effect is 50 to 150°C. For this reason, it is preferable to provide a cooling device in the first branch line to regulate the temperature of the combustion gas supplied to the exhaust gas path. By installing such a cooling device, it is possible to maintain the optimal temperature range of the adsorption filter and improve its adsorption performance. Furthermore, by preventing overheating of the adsorption filter and suppressing filter degradation, its lifespan can be extended.

[0018] Furthermore, it is preferable to provide an exhaust gas temperature sensor between the connection point of the exhaust gas path to the first branch and the adsorption filter to measure the temperature of the exhaust gas flowing through it, and a combustion gas temperature sensor downstream of the cooling device of the first branch to measure the temperature of the combustion gas flowing through it, and to provide an exhaust gas temperature adjustment means that adjusts the temperature of the exhaust gas supplied to the adsorption filter based on the temperatures measured by these sensors. This configuration allows for real-time measurement of exhaust and combustion gas temperatures, and enables adjustment of the exhaust gas temperature supplied to the adsorption filter based on the measurement results. This allows the adsorption filter to maintain its optimal temperature range (e.g., 50-150°C), maximizing its adsorption capacity. In particular, if the exhaust gas temperature is too high, the adsorbent material (activated carbon, zeolite, silica gel, etc.) in the adsorption filter deteriorates, reducing its adsorption performance. Therefore, adjusting the temperature to an appropriate range can prevent the deterioration of the adsorbent material and extend the filter's lifespan. Conversely, if the exhaust gas temperature is too low, the adsorption efficiency decreases, so supplying an appropriate amount of combustion gas can adjust the temperature and maintain adsorption performance. Furthermore, by properly managing the temperature of the adsorption filter, the frequency of filter replacement can be reduced, thereby lowering maintenance costs. In addition, fluctuations in exhaust gas temperature prevent instability in treatment efficiency, ensuring stable operation of the exhaust gas treatment system.

[0019] Furthermore, the catalyst filter may be equipped with a catalyst filter temperature sensor for measuring the temperature of the catalyst filter, and a catalyst filter temperature adjustment means may be provided to adjust the temperature of the catalyst filter based on the temperature measured by the catalyst filter temperature sensor. By adding this configuration, the reaction temperature of the catalyst filter can be maintained within an optimal range (for example, approximately 200-400°C), allowing the catalyst to exert its maximum activity. Furthermore, by preventing overheating and undercooling, catalyst degradation can be suppressed, enabling stable operation over a long period. In addition, optimal temperature control reduces unnecessary energy consumption, improving the overall energy efficiency of the system.

[0020] The exhaust gas path may be further provided with an exhaust gas sensor downstream of the filter unit for measuring the concentration of harmful substances in the exhaust gas, and a concentration adjustment means for controlling the temperature of the catalytic filter or the flow rate of combustion gas supplied to the filter unit based on the measurement value of the exhaust gas sensor. By adopting this configuration, it becomes possible to monitor the concentrations of harmful substances such as NOx, SOx, and VOCs in the exhaust gas in real time and optimize the catalytic filter temperature and combustion gas supply accordingly. This improves the reaction efficiency of the catalytic filter, suppresses unnecessary energy consumption, and improves the overall energy efficiency of the system. In addition, by automatically adjusting so that the emission concentration of harmful substances does not exceed environmental standards, the reliability of exhaust gas treatment is improved and the environmental impact is reduced.

[0021] Furthermore, the heat exchanger recovers heat from the combustion gas by heating the heat transfer medium with the combustion gas, and supplies the heat transfer medium to waste heat utilization equipment (for example, boilers, steam turbines, district heating equipment, industrial process heating equipment, hot water supply equipment). In this configuration, waste heat from the exhaust gas treatment system can be effectively utilized, and surplus energy can be reused for power generation, heating, and industrial applications. This reduces wasted waste heat, improves the overall energy efficiency of the system, and minimizes the need for additional energy from external sources. Furthermore, reusing heat reduces CO2 emissions and lowers the environmental impact. [Effects of the Invention]

[0022] As described above, the exhaust gas treatment system according to the present invention provides the following effects: (1) In the exhaust gas treatment system of the present invention, harmful substances such as nitrogen oxides (NOx), sulfur oxides (SOx), and volatile organic compounds (VOCs) in the exhaust gas are effectively removed by a filter unit (a two-stage treatment consisting of physical collection by an adsorption filter and chemical decomposition by a catalytic filter), and further, by promoting the catalytic reaction with the supply of combustion gas, a higher decomposition efficiency than conventional technology can be achieved (improved efficiency of harmful substance removal). (2) In the present invention, by providing a temperature sensor and temperature control means for maintaining the reaction temperature of the catalytic filter within an optimal range, the additional heating energy required to maintain high temperatures, which was necessary in conventional exhaust gas treatment technologies, is suppressed, and by appropriately adjusting the amount of combustion gas supplied, the overall energy consumption can be minimized while maintaining the reaction efficiency of the catalyst (reduction of energy consumption). (3) In the present invention, by providing a heat exchanger that recovers heat from combustion gases, excess thermal energy generated during the exhaust gas treatment process can be recovered and reused according to external heat demand, thereby promoting the effective use of energy and improving the overall energy efficiency of the system (improvement of energy efficiency through effective use of waste heat). (4) In the present invention, by optimally controlling the temperature of the catalytic filter and the flow rate of combustion gas based on the measurements of the exhaust gas sensor, unnecessary energy consumption is suppressed, catalyst degradation is suppressed by appropriate temperature management of the catalytic filter, and filter life is extended by providing a cooling device to maintain the optimal temperature of the adsorption filter, thereby reducing overall maintenance costs (reduction of operating costs). (5) In this invention, by combining real-time monitoring of harmful substances using an exhaust gas sensor with automatic adjustment of the catalytic filter temperature and combustion gas supply amount, the exhaust gas treatment capacity is always maintained in an optimal state, ensuring that environmental standards are reliably met and preventing air pollution. Furthermore, by utilizing biomass combustion gas, CO2 emissions are reduced, contributing to sustainable environmental protection (improved reliability of exhaust gas treatment and reduced environmental burden). (6) In this invention, the lifespan of the adsorption filter is extended by reducing the burden on the adsorption filter through decomposition treatment using a catalytic filter, and the frequency of filter replacement is reduced by utilizing regeneration technology for the adsorption filter. Furthermore, the generation of secondary waste associated with exhaust gas treatment is suppressed by recovering and reusing the ash generated in the biomass combustion chamber, thereby enabling a reduction in environmental burden and effective use of resources (suppression of secondary waste generation). [Brief explanation of the drawing]

[0023] [Figure 1]This figure shows an example of the overall configuration of the exhaust gas treatment system according to the present invention. [Figure 2] This is a schematic diagram showing a biomass combustion chamber used in the exhaust gas treatment system according to the present invention. [Figure 3] This is a diagram illustrating a heat exchanger used in the exhaust gas treatment system according to the present invention. [Figure 4] This is a diagram illustrating an ash recovery device used in the exhaust gas treatment system according to the present invention. [Figure 5] This flowchart shows an example of the control operation of the first flow control valve and cooling device of the first branch circuit. [Figure 6] This flowchart shows an example of the control operation of the second flow control valve of the second branch circuit. [Modes for carrying out the invention]

[0024] Hereinafter, embodiments of the exhaust gas treatment system according to the present invention will be described with reference to the attached drawings.

[0025] Figure 1 shows the overall configuration of the exhaust gas treatment system. This exhaust gas treatment system 1 combines filter technology and energy recovery technology to purify exhaust gas G2 generated from factories and power plants and remove harmful substances. It consists of a biomass combustion chamber 2, a combustion gas path 3, an exhaust gas path 4, a filter unit 5 (adsorption filter 51 and catalytic filter 52), a first branch 6, a second branch 7, a heat exchanger 8, and an ash recovery device 9. It purifies exhaust gas G2 to reduce harmful components and effectively utilizes the generated thermal energy.

[0026] (Biomass combustion chamber) The biomass combustion chamber 2 plays a role in the exhaust gas treatment system 1 by burning biomass fuel 10 to generate high-temperature combustion gas G1. This combustion gas G1 facilitates the exhaust gas purification process and contributes to improving the overall energy efficiency of the system. As shown in Figure 2, the biomass combustion chamber 2 is equipped with a biomass input device 21, which ensures a stable supply of biomass fuel (wood pellets, agricultural residues, etc.) 22. The combustion process is controlled by a combustion control device 23, which maintains the combustion temperature and oxygen supply at optimal levels. This improves combustion efficiency and minimizes the generation of unburned components.

[0027] The combustion gases generated during the combustion process include carbon dioxide (CO2), water vapor (H2O), carbon monoxide (CO), and nitrogen oxides (NOx). These combustion gases, when mixed with the exhaust gas described later, have the effect of promoting the decomposition of harmful substances. The biomass combustion chamber 2 is equipped with an exhaust gas sensor 24, which monitors the composition of the generated gases in real time and adjusts the combustion conditions appropriately to achieve a stable combustion process.

[0028] (Combustion gas path) The combustion gas path 3 is a flow path that guides the combustion gas generated in the biomass combustion chamber 2 to the outlet 3a and also supplies a portion of it to the exhaust gas path 4. By properly mixing the combustion gas G1 with the exhaust gas G2 and by supplying it directly to the filter unit 5 to enhance the filter's function, the purification effect of the exhaust gas G2 in the filter unit 5 is improved. Furthermore, by effectively utilizing the heat of the combustion gas G1, energy is used efficiently. Thus, the combustion gas path 3 functions as an important flow path in the exhaust gas treatment system 1, recovering and releasing the heat of the combustion gas G1 and utilizing a portion of it for exhaust gas treatment.

[0029] (Exhaust gas path) The exhaust gas path 4 is a passage that takes in exhaust gas G2 generated from factories and power plants, mixes it with combustion gas G1, and then sends it to the filter unit 5. The role of this exhaust gas path 4 is to properly treat the exhaust gas G2 and achieve efficient purification. Exhaust gas G2 first flows into the system through the exhaust gas intake 4a. It is then mixed in an appropriate ratio with combustion gas G1 supplied via the first branch passage 6, which will be described later. This mixing process is crucial, as the uniform mixing of combustion gas G1 and exhaust gas G2 maximizes the adsorption and decomposition effect of the filter unit 5.

[0030] By mixing combustion gas G1 with exhaust gas G2, not only is the temperature of exhaust gas G2 properly adjusted, but the decomposition of harmful substances is also promoted. In particular, the carbon monoxide (CO) and thermal energy in combustion gas G1 assist in the chemical changes of nitrogen oxides (NOx) in exhaust gas G2, improving the efficiency of purification. Thus, exhaust gas path 4 plays a role in effectively purifying exhaust gas G2 by mixing it with combustion gas G1 in order to properly treat it.

[0031] (Filter unit) The filter unit 5 is installed in the exhaust gas path 4 and is the main device for purifying the exhaust gas G2. It consists of two stages: an adsorption filter 51 and a catalytic filter 52. The adsorption filter 51 is a device that purifies exhaust gas by physically capturing harmful substances such as NOx, SOx, and VOCs in an adsorbent. It uses adsorbents such as activated carbon and zeolite to remove particulate matter (PM) and volatile organic compounds from the exhaust gas. The adsorbed harmful substances are further decomposed by the subsequent catalytic filter 52. The catalytic filter 52 is a device that decomposes harmful substances that could not be removed by the adsorption filter 51 through a chemical reaction. An SCR catalyst (selective catalytic reduction reaction) is used to decompose NOx into harmless nitrogen (N2) and oxygen (O2). Chemical reactions are accelerated on the catalyst surface, and harmful substances are decomposed, significantly reducing the environmental impact of exhaust gas G2.

[0032] (First fork in the road) The first branch 6 connects the combustion gas path 3 and the exhaust gas path 4, and is a path for mixing an appropriate amount of combustion gas G1 with exhaust gas G2. This process improves the treatment effect of exhaust gas G2 and increases the overall efficiency of exhaust gas purification of the system. The first branch line 6 is equipped with a first flow control valve 61, which maintains the optimal mixing ratio by adjusting the supply amount of combustion gas G1. This first flow control valve 61 is automatically controlled according to the operating conditions of the system and is designed to maximize the treatment efficiency of exhaust gas G2.

[0033] The temperature of the combustion gas G1 is one of the factors that greatly affects the effectiveness of the filter unit 5, so proper temperature control is important. Therefore, a cooling device 62 is installed on the first branch line to cool the combustion gas G1 passing through it. By adjusting the opening of the first flow control valve 61, the combustion gas G1 and exhaust gas G2 are properly mixed, which equalizes the temperature and allows for more effective adsorption of harmful substances and catalytic reactions within the filter unit. In particular, the high-temperature components in the combustion gas G1 promote the reaction of the exhaust gas G2, allowing for smoother removal of NOx and SOx. Thus, the first branch passage 6 is an important flow path with an adjustment function to ensure proper mixing of combustion gas G1 and exhaust gas G2 and supply them to the filter unit 5 in an optimal state. In addition, it plays a role in further improving the efficiency of exhaust gas treatment by controlling the temperature of combustion gas G1.

[0034] (Second fork in the road) The second branch 7 connects the combustion gas path 3 and the catalytic filter 52, and is a flow path for supplying the combustion gas G1 to the catalytic filter 52 in an appropriate amount. In other words, the catalytic filter 52 uses the supplied combustion gas G1 to promote a chemical reaction that converts harmful substances such as NOx into harmless components. By appropriately managing the supply amount of combustion gas G1, the reduction reaction within the catalytic filter 52 proceeds smoothly, and harmful components in the exhaust gas are effectively removed. In the second branch 7, it is necessary to appropriately adjust the flow rate of combustion gas G1 sent to the catalytic filter 52. If the supply of combustion gas G1 is too high, the catalytic reaction will become excessive, which may disrupt the balance of exhaust gas treatment. Conversely, if the supply of combustion gas G1 is insufficient, the catalytic reaction will not proceed sufficiently, resulting in incomplete removal of harmful substances such as NOx. Therefore, the second branch line 7 is equipped with a second flow control valve 71 that enables flow rate control, and the flow of combustion gases is adjusted to be optimized according to the operating conditions of the system. This control maximizes the performance of the catalytic filter and improves the effectiveness of exhaust gas treatment.

[0035] The combustion gas G1 supplied through the second branch 7 plays a role in promoting the chemical reaction within the catalytic filter 52. In the catalytic filter 52, a reduction reaction using the combustion gas G1 takes place, converting harmful substances such as NOx into harmless components such as nitrogen (N2) and water (H2O). When this process functions properly, the exhaust gas G2 is released into the atmosphere in a state that meets environmental standards. Since the efficiency of the catalytic reaction depends greatly on the amount and temperature of the supplied combustion gas, the flow rate and temperature of the combustion gas G1 are controlled in the second branch 7 to maintain optimal conditions. Thus, the second branch 7 plays a crucial role in optimizing the catalytic reaction and improving the efficiency of exhaust gas treatment by appropriately supplying combustion gas G1 to the catalytic filter 52. In other words, by maintaining an appropriate supply amount of combustion gas G1, it is possible to maximize the performance of the catalytic filter 52. Furthermore, by controlling the flow rate, the operation of the entire system is stabilized, and effective removal of NOx from the exhaust gas is achieved.

[0036] (heat exchanger) The heat exchanger 8 is installed at the downstream end of the combustion gas path 3 and is a device that recovers the thermal energy of the combustion gas G1 and improves the efficiency of energy utilization. As the combustion gas G1 passes through, its heat is transferred to a heat transfer medium (e.g., water or oil) flowing through the internal heat exchange tube 81, and the heated heat transfer medium is supplied to waste heat utilization equipment such as boilers, heating equipment, industrial process heating equipment, steam turbines, and hot water supply equipment. This heat exchange regulates the temperature of the combustion gases, allowing for efficient energy utilization and reducing wasted heat. In particular, since high-temperature combustion gases result in significant energy loss, this system recovers waste heat through the heat exchanger 8 and utilizes it in power generation and heating processes, thereby optimizing overall energy utilization efficiency.

[0037] (Ash recovery device) The ash recovery device 9 is located at or immediately after the connection point between the combustion gas path 3 and the biomass combustion chamber 2 (in this example, it is located between the biomass combustion chamber 2 and the first branch path 6), and recovers ash (solid particles) from the combustion gas generated in the biomass combustion chamber 2. This ash recovery device 9 includes an ash collection unit 91 that reliably recovers even fine ash using filters and cyclone separators from the ash discharged from the biomass combustion chamber 2, a chemical treatment device 92 for processing the ash into alkaline fertilizer, and a compression molding device 93 for forming it into building blocks, thereby reusing the ash as fertilizer or construction material.

[0038] This ash recovery device 9 efficiently recovers ash immediately after the combustion chamber (early recovery of ash), thereby reducing the load on the combustion gas path 3 and filter unit 5, and improving the overall operating efficiency of the system. Specifically, by removing ash upstream of the branching paths (first branching path 6, second branching path 7), the flow of combustion gas after branching is made uniform, and adverse effects on the system due to ash accumulation are avoided. Furthermore, because it is located upstream of the branching paths (first branching path 6, second branching path 7), it is possible to separate ash without affecting the flow of combustion gas after branching. As a result, the performance of the adsorption filter 51 and catalytic filter 52 is maintained, and stable operation of the filter unit 5 over a long period of time is achieved.

[0039] In the above configuration, the exhaust gas treatment system 1 optimizes the performance of the adsorption filter 51 and the catalytic filter 52 by combining the temperature and flow rate control of the combustion gas using the first flow control valve 61 and cooling device 62 of the first branch 6, and the combustion gas supply control to the catalytic filter 52 using the second flow control valve 71 of the second branch 7, thereby achieving efficient exhaust gas treatment. The adsorption filter 51 uses adsorbents such as activated carbon, zeolite, and silica gel, each with its own optimal temperature range corresponding to its physical and chemical properties. In this system, the optimal temperature range is set to 50-150°C to maximize the performance of the adsorption filter 51. Therefore, it is necessary to adjust the temperature of the exhaust gas G2 to an appropriate range so that the adsorption capacity of the adsorption filter 51 can be fully realized.

[0040] However, the temperature of exhaust gases emitted from factories and power plants is usually high, at 200-400°C. If these gases are introduced into the adsorption filter 51, the surface structure of the adsorbent may be damaged, potentially reducing its adsorption performance. Similarly, combustion gas G1 is also usually very high, at 600-1000°C. If it is mixed directly with exhaust gas G2, it becomes difficult to maintain the appropriate temperature range of the adsorption filter 51. Therefore, it is necessary to adjust the temperature of combustion gas G1 to 50-100°C using the cooling device 62 provided in the first branch line 6, and then mix it with exhaust gas G2 in an appropriate ratio to maintain the temperature of the adsorption filter 51 at 50-150°C.

[0041] On the other hand, the catalytic filter 52 plays a role in chemically decomposing harmful substances, and its optimal temperature range is 200-400°C. If the supply amount of combustion gas G1 is not appropriate, the temperature of the catalytic filter 52 will rise or fall excessively, leading to catalyst degradation and a decrease in reaction efficiency. In addition, the catalytic filter 52 requires an appropriate amount of reducing gases such as carbon monoxide (CO) and hydrogen (H2) to convert NOx into harmless N2 and H2O. However, if the supply amount is insufficient, the reduction reaction will not proceed, and the NOx removal rate will decrease. On the other hand, if the supply amount is excessive, the surface of the catalyst may become contaminated with unreacted gases, potentially reducing catalytic activity. Based on the above points, the exhaust gas treatment system 1 controls the temperature and flow rate of the combustion gas using the first flow control valve 61 and cooling device 62 of the first branch 6, and controls the supply of combustion gas to the catalytic filter 52 using the second flow control valve 71 of the second branch 7, thereby optimizing the performance of each filter.

[0042] (1) Control of the first flow control valve 61 and cooling device 62 of the first branch line The first branch 6 plays a role in maintaining the optimal temperature range (50-150°C) of the adsorption filter 51 by adjusting the temperature of the combustion gas G1 and mixing it with the exhaust gas G2 in an appropriate ratio. Since the combustion gas G1 is at a very high temperature of 800-1200°C immediately after being generated in the biomass combustion chamber 2, supplying it as is could significantly degrade the performance of the adsorption filter 51. Therefore, the cooling device 62 installed in the first branch 6 cools the temperature of the combustion gas G1 to an appropriate range (for example, 50-100°C), and then the first flow rate control valve 61 is operated to mix it with the exhaust gas G2 in an appropriate ratio and control the flow rate so that the inlet temperature of the adsorption filter 51 remains within the range of 50-150°C.

[0043] The purpose of this control is to optimize the exhaust gas temperature and reduce the load on the adsorption filter 51. To achieve this, an exhaust gas temperature sensor 11 is installed upstream of the adsorption filter 51 between the connection point of the exhaust gas path 4 to the first branch passage 6 and the adsorption filter 51. Additionally, a combustion gas temperature sensor 12 is installed downstream of the cooling device 62 of the first branch passage 6 to measure the temperature of the combustion gas G1 flowing through it. Through feedback control using these sensors, the temperature and flow rate of the combustion gas G1 are adjusted in real time so that the temperature of the exhaust gas G2 is maintained within the optimal temperature range (50-150°C) of the adsorption filter 51. Specifically, the cooling capacity of the cooling device 62 is controlled to appropriately adjust the temperature of the combustion gas G1, and then the opening degree of the first flow control valve 61 is adjusted to optimize the mixing ratio of exhaust gas G2 and combustion gas G1, thereby maintaining the inlet temperature of the adsorption filter 51 within an appropriate range. This prevents overheating and undercooling, creating an environment in which the adsorption filter 51 can perform at its maximum potential.

[0044] Figure 5 shows a flowchart of an example of a control process for managing the temperature of exhaust gas. In this control flow, the temperature and flow rate of the combustion gas are adjusted in order to maintain the temperature of the exhaust gas supplied to the adsorption filter 51 within an appropriate range (50 to 150°C). To this end, the minimum necessary two temperature sensors (T1 and T2) are utilized: an exhaust gas temperature sensor 11 installed immediately before the adsorption filter 51 (i.e., downstream of the connection point with the first branch passage 6 of the exhaust gas path 4, and upstream of the adsorption filter 51), and a combustion gas temperature sensor 12 installed on the outlet side of the cooling device of the first branch passage. By performing feedback control based on the temperature measurement results of these sensors, the performance of the adsorption filter is maximized.

[0045] First, the exhaust gas temperature (T1) immediately before the adsorption filter, that is, the temperature after the combustion gas G1 and exhaust gas G2 have been mixed in the exhaust gas path 4, is measured using the exhaust gas temperature sensor 11 (step S11). As a result, it is determined whether the measured exhaust gas temperature (T1) is within the appropriate range (50-150°C) (step S12). If T1 is within this appropriate temperature range, no adjustment is necessary, and the process proceeds to optimizing the supply amount of combustion gas G1 (step S16). On the other hand, if T1 is below 50°C or above 150°C, the temperature and flow rate of combustion gas G1 need to be adjusted, and the process proceeds to the next step S13.

[0046] To adjust the temperature of the combustion gas G1, the cooling device 62 installed in the first branch line 6 is activated. The combustion gas G1 is normally at a very high temperature of 600 to 1000°C, and if supplied as is, it would exceed the appropriate temperature range of the adsorption filter 51, so cooling treatment is essential. The cooling device 62 performs appropriate heat exchange with the aim of lowering the temperature of the combustion gas G1 to an appropriate range (50 to 100°C) (step S13).

[0047] Subsequently, the temperature (T2) of the combustion gas G1 that has passed through the cooling device 62 is measured by the combustion gas temperature sensor 12. This measurement confirms whether the cooling process has been performed properly and whether the temperature of the combustion gas G1 has decreased to a range that can be supplied to the adsorption filter 51 (step S14). Specifically, step S15 determines whether the measured temperature (T2) of the combustion gas G1 is within the appropriate range (50-100°C). If T2 is within the range of 50-100°C, the process proceeds to step S16, where the supply amount of combustion gas G1 is adjusted. Conversely, if T2 exceeds 100°C, the process returns to step S13 to increase the output of the cooling device 62 and readjust until the temperature of T2 falls within the appropriate range.

[0048] In step S16, the first flow control valve 61 is operated to mix the cooled combustion gas G1 with the exhaust gas G2 in an appropriate ratio. At this time, the mixing ratio of the combustion gas G1 is adjusted to about 5-20%, preventing excessive supply and suppressing the temperature rise of the adsorption filter 51. Furthermore, the measurement results from the exhaust gas temperature sensor (T1) are used for feedback control to adjust the temperature of the adsorption filter 51 so that it is maintained within an appropriate range.

[0049] Subsequently, the exhaust gas temperature after the combustion gas G1 and exhaust gas G2 have been mixed is measured again (step S17) to reconfirm whether the temperature supplied to the adsorption filter 51 is within the appropriate range (50-150°C) (step S18). If the measured value of T1 is within the range of 50-150°C, it becomes possible to supply optimized exhaust gas G1, and the current gas supply to the adsorption filter 51 is maintained (step S19). In other words, exhaust gas with properly adjusted temperature and flow rate is supplied to the adsorption filter 51 to remove harmful substances such as NOx, SOx, and VOCs. If T1 is still outside the appropriate range, return to step S13 to re-adjust the cooling and flow rate of the combustion gases.

[0050] By employing the above control flow, the optimal temperature range (50-150°C) of the adsorption filter can be maintained, maximizing the adsorption efficiency of harmful substances such as NOx, SOx, and VOCs. Preventing overheating or overcooling suppresses the degradation of the adsorbent material, enabling long-term stable operation. Furthermore, by monitoring the exhaust gas temperature in real time and adjusting the supply of combustion gases, it is possible to prevent sudden temperature fluctuations and improve system stability. This reduces the load on the adsorption filter, decreases the frequency of filter replacement, and is expected to reduce maintenance costs. Furthermore, by operating the cooling device 62 to the minimum necessary level and appropriately controlling the first flow control valve 61, unnecessary energy consumption is suppressed, and the energy efficiency of exhaust gas treatment is improved. By adjusting the temperature to an appropriate range, the decomposition process in the catalytic filter after adsorption proceeds smoothly, and the overall exhaust gas treatment efficiency of the system is also improved. This increases the removal rate of harmful substances, leading to a reduction in environmental impact, and also enables a reduction in operating costs through optimal temperature control.

[0051] (2) Control of the second flow control valve 71 of the second branch The second branch 7 plays a role in promoting the catalytic reaction by supplying combustion gas G1 to the catalytic filter 52, thereby efficiently decomposing harmful substances such as NOx and SOx. Since the catalytic filter exhibits optimal catalytic activity within a temperature range of 200-400°C, it is necessary to appropriately control the amount and temperature of the combustion gas supply.

[0052] Immediately after being generated in the biomass combustion chamber 2, the combustion gas G1 is at a very high temperature of 800-1200°C. However, by the time it is supplied to the second branch 7, its temperature decreases within the combustion gas path and is usually in the range of 200-500°C. However, when supplied to the catalyst filter 52, it is required to maintain the temperature within the optimal range (200-400°C). If the supply temperature is below 200°C, the catalytic reaction will not proceed sufficiently, and if it exceeds 400°C, the deterioration of the catalyst will accelerate, and there is a risk of shortening the catalyst's lifespan. For this reason, a catalyst filter temperature sensor 13 is installed inside or on the surface of the catalyst filter 52 to measure the temperature of the catalyst filter 52. By using feedback control with this catalyst filter temperature sensor, the temperature of the combustion gas G1 is monitored, and the flow rate of the combustion gas G1 is adjusted to maintain the appropriate range.

[0053] Furthermore, in order to promote the NOx reduction reaction in the catalytic filter 52, it is necessary to supply an appropriate amount of carbon monoxide (CO) and hydrogen (H2) from the combustion gas G1. If these components are insufficient, the reduction reaction will not proceed, and the NOx removal rate will decrease. On the other hand, if the supply amount is excessive, the surface of the catalyst may become contaminated with unreacted carbon and other gases, potentially reducing the activity of the catalyst. For this reason, an exhaust gas sensor 14 is installed downstream of the catalytic filter 52 in the exhaust gas path 4, and based on the NOx concentration measurement results from this exhaust gas sensor 14, the opening degree of the second flow control valve 71 is appropriately adjusted to control the supply amount of reducing gas within the optimal range (10-30%).

[0054] The purpose of this control is to maintain the optimal temperature of the catalytic filter 52 and maximize the catalytic reaction by appropriately supplying the reducing gas (combustion gas G1). Feedback control is performed using the catalytic filter temperature sensor 13 and the exhaust gas sensor 14 to maintain the temperature inside the catalytic filter within an appropriate range (200-400°C) and to adjust the amount of combustion gas G1 supplied in real time according to the NOx concentration. Furthermore, in order to maintain the performance of the catalytic converter filter 52, if the flow rate of exhaust gas G2 fluctuates rapidly, the second flow control valve 71 is quickly adjusted to prevent oversupply or undersupply. This makes it possible to extend the lifespan of the catalytic converter filter 52 and achieve stable exhaust gas treatment.

[0055] Figure 6 shows a flowchart of an example of a control process for managing the temperature of such a catalytic filter 52 and the NOx concentration of exhaust gas G2. Since the temperature of the catalytic filter 52 greatly affects the efficiency of the catalytic reaction, first, the temperature of the catalytic filter 52 is measured by the catalytic filter temperature sensor 13 (step S21). Step S22 determines whether the measured temperature of the catalyst filter is within the appropriate range (200-400°C). If the temperature is within this range, the condition is considered appropriate, so temperature control is terminated, and the process proceeds to step S25 (checking NOx concentration), which is described below.

[0056] In contrast, if the temperature of the catalytic filter 52 is below 200°C, the catalytic reaction will not proceed sufficiently, and the reduction of NOx will decrease. Therefore, the second flow control valve 71 is opened to increase the supply amount of combustion gas G1 (step S23). Since the temperature of combustion gas G1 is normally between 200 and 500°C, supplying an appropriate amount can raise the temperature inside the catalytic filter 52. At this time, it is advisable to adjust the temperature step by step, taking into account the effect of increasing the supply amount of combustion gas G1. After that, return to step S21 and measure the temperature of the catalytic filter 52 again.

[0057] Furthermore, if the temperature of the catalytic filter 52 exceeds 400°C, the catalyst may deteriorate and its lifespan shortened. Therefore, the second flow control valve 71 is closed to reduce the supply amount of combustion gas G1 (step S24). By reducing the supply amount, the temperature rise of the catalytic filter 52 is suppressed and adjusted to the appropriate range (200-400°C). After that, the process returns to step S21, and adjustment is continued to keep the temperature within the adjustment range.

[0058] After the temperature of the catalytic converter filter 52 has settled within the appropriate range (200-400°C), the NOx concentration in the exhaust gas is measured by the exhaust gas sensor 14 (step S25). This measurement determines whether the NOx concentration in the exhaust gas is within the range compliant with environmental regulations (within the standard value) (Step S26). If the measurement results indicate that the NOx concentration in the exhaust gas exceeds the standard value, it is necessary to accelerate the catalytic reaction and increase the supply amount of combustion gas. Therefore, the second flow control valve 71 is opened to increase the supply amount of reducing gas (combustion gas G1). In other words, the reduction reaction of NOx is promoted by increasing the reducing components such as carbon monoxide (CO) and hydrogen (H2) in the combustion gas (Step S28). In this case, monitoring of the NOx concentration by the exhaust gas sensor is continued while adjusting the supply amount in stages (Steps S25-S27).

[0059] In contrast, if the NOx concentration is within the standard value, the catalytic reaction is proceeding properly, and the current combustion gas supply amount is maintained (step S28). That is, feedback control using the catalytic filter temperature sensor 13 and the exhaust gas sensor 14 is continued. This allows for real-time monitoring of the catalytic filter's condition and maintenance of an optimal combustion gas supply, enabling long-term stable operation. Furthermore, it allows for maintaining exhaust gas treatment that meets environmental standards and optimizing the system's energy efficiency.

[0060] In the example described above, the filter unit 5 was shown as having an adsorption filter 51 and a catalyst filter 52 configured as separate components. However, the adsorption filter and catalyst filter could also be designed as an integrated module to create a more compact filter unit. Furthermore, while the adsorption filter 15 shown primarily uses a single type of adsorbent (e.g., activated carbon or zeolite), multiple adsorbents may be arranged in layers to achieve an optimal adsorption process for each specific harmful substance (NOx, SOx, VOC) (e.g., activated carbon in the upper layer to remove VOCs, and zeolite in the lower layer to adsorb NOx). Similarly, the catalytic filter may also be configured in a multilayer structure. For example, by using different catalysts in a multilayer structure, a low-temperature catalyst (active at 200-300°C) may be placed in the first layer and a high-temperature catalyst (active at 300-400°C) in the second layer to achieve an optimal catalytic reaction in response to the temperature fluctuations of the exhaust gas. Alternatively, a combination of oxidation and reduction catalysts may be used, with the oxidation catalyst placed in the first layer to oxidize and decompose hydrocarbons and carbon monoxide, and the reduction catalyst in the second layer to neutralize NOx. [Explanation of Symbols]

[0061] 1. Exhaust gas treatment system 2. Biomass combustion chamber 3. Combustion gas path 4. Exhaust gas path 5 Filter Units 51 Adsorption filter 52 Catalytic Filter 6. First fork in the road 7. Second fork in the road 8 Heat exchanger 9. Ash recovery device 11. Exhaust gas temperature sensor 12. Combustion gas temperature sensor 13. Catalytic Filter Temperature Sensor 14. Exhaust gas sensor G1 Combustion Gas G2 exhaust gas 61. First flow control valve 62 Cooling device 71. Second flow control valve

Claims

1. A combustion chamber for burning biomass, A combustion gas path for releasing combustion gases generated in the combustion chamber, An exhaust gas path that releases exhaust gases emitted from industrial facilities, A filter unit is placed on the exhaust gas path and adsorbs harmful substances in the exhaust gas, and decomposes the adsorbed harmful substances by a catalytic reaction. A first branch path that branches off from the combustion gas path and supplies the combustion gas to the upstream side of the exhaust gas path from the filter unit, A second branch path that branches off from the aforementioned combustion gas path and supplies the combustion gas to the filter unit, Downstream from the second branch of the combustion gas path, there is a heat exchanger that recovers heat from the combustion gas flowing through the combustion gas path, An ash recovery device is positioned at or immediately after the connection point between the combustion gas path and the combustion chamber, and recovers ash generated after biomass combustion. An exhaust gas treatment system characterized by comprising the following:

2. The aforementioned filter unit is An adsorption filter that collects harmful substances contained in exhaust gas through physical adsorption, The system includes a catalytic filter that decomposes and removes harmful substances collected by the adsorption filter through a catalytic reaction, thereby rendering them harmless. The second branch supply the combustion gas to the catalytic filter. The exhaust gas treatment system according to claim 1, characterized in that it is as follows.

3. The exhaust gas treatment system according to claim 1 or 2, characterized in that each of the first branch and the second branch is provided with a flow rate adjustment means for adjusting the amount of combustion gas supplied.

4. The exhaust gas treatment system according to claim 2, wherein the first branch is provided with a cooling device for adjusting the temperature of the combustion gas supplied to the exhaust gas path.

5. An exhaust gas temperature sensor is provided between the connection point of the exhaust gas path to the first branch and the adsorption filter to measure the temperature of the exhaust gas flowing therein, and a combustion gas temperature sensor is provided downstream of the cooling device in the first branch to measure the temperature of the combustion gas flowing therein. An exhaust gas temperature adjustment means is provided to adjust the temperature of the exhaust gas supplied to the adsorption filter based on the temperatures measured by these sensors. The exhaust gas treatment system according to claim 4.

6. The catalyst filter is provided with a catalyst filter temperature sensor for measuring the temperature of the catalyst filter. This system includes a catalyst filter temperature adjustment means that adjusts the temperature of the catalyst filter based on the temperature measured by the catalyst filter temperature sensor. The exhaust gas treatment system according to claim 2, characterized in that way.

7. The exhaust gas path is equipped with an exhaust gas sensor downstream of the filter unit for measuring the concentration of harmful substances in the exhaust gas. The exhaust gas treatment system according to claim 2, further comprising concentration adjustment means for controlling the temperature of the catalytic filter or the flow rate of combustion gas supplied to the filter unit based on the measurement value of the exhaust gas sensor.

8. The exhaust gas treatment system according to claim 1 or 2, wherein the heat exchanger recovers heat from the combustion gas by heating a heat transfer medium with the combustion gas, and supplies the heat transfer medium to a waste heat utilization facility.

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