Biomass torrefaction coupled novel denitration agent pyrolysis reactor and system thereof

Abstract

A novel biomass baking coupled with denitrification agent pyrolysis reactor and system includes a housing with a heating chamber on its inner wall, the heating chamber being connected to a medium inlet and a medium outlet. A dual-shaft stirring system is installed inside the housing, comprising two hollow stirring drums rotatably connected to the inner wall of the housing. Each hollow stirring drum has spiral blades on its exterior, and a heating device is installed inside both hollow stirring drums. This invention, by combining biomass baking and ammonium carbamate pyrolysis, generates diluted ammonia gas. This diluted ammonia gas diffuses and mixes better in the boiler than pure NH3, reducing the amount of ammonia gas used for denitrification and preventing ammonia escape. Furthermore, the biomass baking process generates gases such as H2O, H2, CO, CO2, and CH4, which are injected into the boiler along with the ammonia gas, lowering the local temperature and creating a fuel-rich, oxygen-depleted environment, thus reducing NOx production.

Description

Technical Field

[0001] This invention relates to the field of denitrification technology for thermal power boilers, and in particular to a novel biomass baking coupled with a denitrification agent pyrolysis reactor and its system. Background Technology

[0002] Current mainstream flue gas denitrification technologies (SCR, SNCR) rely on liquid ammonia or urea as reducing agents. However, these technologies have many drawbacks, such as the risk of ammonia escape, which not only generates PM2.5 precursors but also triggers a series of secondary pollution problems. Traditional urea-to-ammonia processes, due to the involvement of water, result in high energy consumption, with the latent heat of water vaporization accounting for approximately 30%-50% of total energy consumption. They also produce byproducts such as isocyanates and biuret, placing a heavy burden on the sustainable development of the industry.

[0003] Therefore, this application proposes a reactor and system that uses ammonium carbamate as a denitrification agent and is coupled with biomass roasting technology to solve the problems in the current mainstream flue gas denitrification process. Summary of the Invention

[0004] The present invention aims to at least partially solve one of the technical problems in the related art.

[0005] To achieve the above objectives, this invention proposes a novel biomass baking coupled with denitrification agent pyrolysis reactor, comprising a box body, wherein a heating chamber is provided on the inner side wall of the box body, and the heating chamber is connected to a medium inlet and a medium outlet;

[0006] The chamber is equipped with a dual-shaft stirring system, which includes two hollow stirring cylinders rotatably connected to the inner wall of the chamber. Each hollow stirring cylinder is equipped with a spiral blade, and a heating device is installed inside the two hollow stirring cylinders.

[0007] This invention combines biomass baking and ammonium carbamate pyrolysis to generate diluted ammonia. The diluted ammonia diffuses and mixes better in the boiler than pure NH3, which can reduce the amount of ammonia used for denitrification and prevent ammonia escape. In addition, gases such as H2O, H2, CO, CO2 and CH4 are generated during the biomass baking process. These gases are injected into the boiler along with the ammonia, which can reduce the local temperature, create a fuel-rich and oxygen-depleted environment, and reduce NOx production.

[0008] Optionally, the heating device includes two heating rods respectively inserted into two hollow stirring cylinders. Both heating rods are hollow, and an arc-shaped pipe connects the two hollow heating rods. The arc-shaped pipe and the two heating rods are arranged in a U-shape, and a medium exchange port connects the arc-shaped pipe and the heating chamber.

[0009] Furthermore, an insulation layer is provided on the outside of the enclosure.

[0010] Furthermore, the heating medium in the heating chamber and the heating rod is either flue gas or heat transfer oil, and the heat transfer oil is either synthetic heat transfer oil or biphenyl-diphenyl ether mixture heat transfer oil.

[0011] Furthermore, the flue gas temperature is set to 500-600℃, and the heat transfer oil temperature is set to 300-400℃.

[0012] This application also provides a system using a novel denitrification agent pyrolysis reactor coupled with biomass baking as described in any of the above claims, including a pyrolysis system and a boiler system; The pyrolysis system includes the pyrolysis reactor, which is connected to a biomass silo and a novel denitrification agent conveying component. The novel denitrification agent conveying component includes a novel denitrification agent silo, a first cyclone separator, and a quantitative conveyor connected sequentially along the novel denitrification agent conveying sequence. A conveying fan is connected to the outlet pipe of the novel denitrification agent silo, and the conveying direction of the conveying fan is from the outlet of the novel denitrification agent silo to the inlet of the cyclone separator. The quantitative conveyor is connected to the denitrification agent inlet of the pyrolysis reactor; The boiler system includes a boiler body, and the gas inlet of the boiler body is connected to the outlet of the pyrolysis reactor.

[0013] Furthermore, a gas-solid separation system is connected between the first cyclone separator and the novel denitrification agent silo. The inlet of the gas-solid separation system is connected to the gas outlet of the cyclone separator, the solid outlet of the gas-solid separation system is connected to the feed inlet of the novel denitrification agent silo, and the gas outlet of the gas-solid separation system is connected to the gas inlet of the boiler.

[0014] Furthermore, the temperature of the pyrolysis reactor is controlled at 250-350℃.

[0015] Furthermore, the ratio of the processing capacity of the pyrolysis system to the capacity of the boiler body is controlled at 2-10 kg / MJ.

[0016] Furthermore, when the boiler body is configured as a micro-circulating fluidized bed, the tail end of the boiler body is connected to a second cyclone separator, and the solid outlet of the second cyclone separator is connected to the boiler body. When the boiler body is configured as a pulverized coal boiler, the tail end of the boiler body is connected to the tail flue.

[0017] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a front view schematic diagram of the structure of a novel biomass baking coupled with a denitrification agent pyrolysis reactor according to the present invention; Figure 2 This is a side view schematic diagram of the structure of a novel biomass baking coupled with a denitrification agent pyrolysis reactor according to the present invention; Figure 3 This is a schematic diagram of the heating device structure of a novel denitrification agent pyrolysis reactor coupled with biomass baking according to the present invention; Figure 4 This is a schematic diagram of a system according to the present invention that uses a biomass baking coupled with a novel denitrification agent pyrolysis reactor; Figure 5 This is a schematic diagram of another system according to the present invention that uses a biomass baking coupled with a novel denitrification agent pyrolysis reactor.

[0019] Explanation of reference numerals in the attached figures: 100. Housing; 110. Heating chamber; 111. Medium inlet; 112. Medium outlet; 120. Insulation layer; 200. Twin-shaft stirring system; 210. Hollow stirring drum; 220. Spiral blades; 230. Heating device; 231. Heating rod; 232. Arc-shaped pipe; 240. Motor; 300. Pyrolysis system; 310. Pyrolysis reactor; 320. Biomass silo; 330. New denitrification agent silo; 340. First cyclone separator; 350. Quantitative conveyor; 360. Conveying fan; 370. Gas-solid separation system; 400. Boiler system; 410. Boiler body; 420. Second cyclone separator; 430. Tail flue. Detailed Implementation

[0020] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0021] This invention proposes a novel biomass baking coupled with a denitrification agent pyrolysis reactor, as described below. Figures 1 to 3 Please provide a detailed explanation.

[0022] A novel biomass baking coupled with denitrification agent pyrolysis reactor 310 includes a housing 100, a heating chamber 110 provided on the inner wall of the housing 100, a medium inlet 111 and a medium outlet 112 connected to the heating chamber 110 for the heating medium to flow within the heating chamber 110; the housing 100 is provided with a first feed inlet for biomass and a second feed inlet for ammonium carbamate, and the housing 100 is provided with a gas outlet for the pyrolysis gas to be discharged, the pyrolysis gas being discharged from the gas outlet and then entering the boiler body 410; The housing 100 is equipped with a dual-shaft stirring system 200, which includes two hollow stirring drums 210 rotatably connected to the inner wall of the housing 100. Each hollow stirring drum 210 is equipped with a spiral blade 220, and a heating device 230 is installed inside the two hollow stirring drums 210. Two motors 240 are installed on one outer wall of the housing 100, and the two motors 240 independently drive the two hollow stirring drums 210 to rotate inside the housing 100.

[0023] It should be noted that there are two chemical reaction equations for the decomposition of ammonium carbamate. One of them is the thermal decomposition of ammonium carbamate, namely NH2COONH4(s). The first reaction is 2NH3(g) + CO2(g), and increasing the temperature promotes this reaction. The second reaction is NH2COONH4 + H2O → NH4HCO3 + NH3·H2O → 2NH3↑ + CO2↑ + H2O. This shows that increasing the temperature and the presence of water promote the rapid decomposition of ammonium carbamate. Analyzing the chemical formula for the decomposition of ammonium carbamate, the reaction can be further accelerated under conditions of increased temperature, sufficient moisture, and adequate dilution of NH3 and CO2.

[0024] Biomass roasting technology is a mild thermochemical pretreatment technique that effectively reduces carbon emissions. It retains 90% of the energy in the original biomass and, under low temperature (180-300 ℃) and low oxygen (oxygen content ≤21%) conditions, effectively removes moisture and hemicellulose from the biomass, releasing a large amount of light volatiles and generating a large amount of solids and a certain amount of condensed liquid (bio-oil, water vapor, etc.) and non-condensable gases (CO, CO2, and CH4, etc.). This regulates the physicochemical properties of the biomass and enhances its thermochemical capacity. During the biomass roasting process, low-energy substances such as water, hemicellulose, and some volatile extracts are decomposed, thus greatly preserving the original energy of the biomass and increasing its energy density.

[0025] The biomass roasting process generates gases such as H2O, H2, CO, CO2, and CH4. These gases further dilute the NH3 and CO2 generated from ammonium carbamate, promoting the formation of NH2COONH4(s). The reaction 2NH3(g) + CO2(g) shifts to the right. Furthermore, the diluted NH3 diffuses and mixes better in the boiler than pure NH3, which can reduce the amount of ammonia used for denitrification, prevent ammonia escape, and avoid a series of serious consequences caused by ammonia escape, such as equipment corrosion, system blockage, catalyst deactivation, environmental pollution, and increased operating costs.

[0026] This invention combines biomass baking and ammonium carbamate pyrolysis. Biomass and ammonium carbamate are placed together in a chamber 100 for pyrolysis. The heating chamber 110 provides overall external heating to the environment inside the chamber 100, creating a favorable temperature environment for pyrolysis. Furthermore, the heating device 230 directly heats the hollow stirring drum 210, transferring heat directly to the mixture of biomass and ammonium carbamate through the spiral blades 220, further accelerating the pyrolysis reaction. After pyrolysis, diluted ammonia is generated. This diluted ammonia diffuses and mixes better than pure NH3 in the boiler, reducing the amount of ammonia needed for denitrification and preventing ammonia escape. Additionally, the biomass baking process generates gases such as H2O, H2, CO, CO2, and CH4, which are injected into the boiler along with the ammonia, lowering the local temperature and creating a fuel-rich, oxygen-depleted environment, thus reducing NOx production.

[0027] In some embodiments, the heating device 230 includes two heating rods 231 respectively inserted into two hollow stirring drums 210. Both heating rods 231 are hollow, and an arc-shaped pipe 232 connects them. The arc-shaped pipe 232 and the two heating rods 231 are arranged in a U-shape, and a medium exchange port connects the arc-shaped pipe 232 to the heating chamber 110. The two heating rods 231 are respectively inserted into the two hollow stirring drums 210, allowing each drum to be heated independently, thus enabling each drum to transfer heat to the mixture more quickly. Connecting the two heating rods 231 through the arc-shaped pipe 232 allows for unified injection and synchronous circulation of the heating medium, facilitating synchronous heat management of the two heating rods 231.

[0028] In some embodiments, an insulation layer 120 is provided on the outside of the chamber 100. The insulation layer 120 can reduce the heat loss of the chamber 100 and prevent excessive heat loss from the heating chamber 110 to the external environment, which could lead to the pyrolysis environment temperature inside the chamber 100 not meeting the standard. By reducing heat loss, the effect of ensuring the reaction temperature inside the chamber 100 is achieved.

[0029] In some embodiments, the heating medium in the heating chamber 110 and the heating rod 231 is either flue gas or heat transfer oil, and the heat transfer oil is either synthetic heat transfer oil or biphenyl-diphenyl ether mixture heat transfer oil.

[0030] Among them, flue gas can realize the utilization of waste heat in thermal power plants, and realize the multiple utilization of thermal energy; Synthetic heat transfer oils are produced through chemical synthesis and have the characteristics of high thermal stability, long service life (up to 3 years or more) and low vapor pressure. They are suitable for closed heat transfer systems. The main types include: alkylbenzene type heat transfer oil, alkylnaphthalene type heat transfer oil, alkylbiphenyl type heat transfer oil and alkyldiphenyl ether type heat transfer oil. The biphenyl-diphenyl ether mixture (commonly known as "Dowtherm A") is a eutectic mixture composed of 26.5% biphenyl and 73.5% diphenyl ether. It has an ultra-wide operating temperature range of -12°C to 400°C, and can withstand 430°C for short periods in strictly designed systems. It can be used for liquid phase heat transfer as well as gas phase heat transfer at 256–400°C, breaking through the single-phase limitation of traditional heat transfer oils.

[0031] In some embodiments, to ensure heat transfer performance, the flue gas temperature is set to 500-600℃ and the heat transfer oil temperature is set to 300-400℃.

[0032] This application also provides a system using any of the above-mentioned biomass baking coupled with a novel denitrification agent pyrolysis reactor, as described below. Figures 4 to 5 Please provide a detailed explanation.

[0033] A system using a biomass baking coupled with a novel denitrification agent pyrolysis reactor includes a pyrolysis system 300 and a boiler system 400; The pyrolysis system 300 includes a pyrolysis reactor 310, which is connected to a biomass silo 320 and a novel denitrification agent conveying component. The novel denitrification agent conveying component includes a novel denitrification agent silo 330, a first cyclone separator 340, and a quantitative conveyor 350 connected sequentially along the novel denitrification agent conveying sequence. A conveying fan 360 is connected to the outlet pipe of the novel denitrification agent silo 330, and the conveying direction of the conveying fan 360 is from the outlet of the novel denitrification agent silo 330 to the inlet of the cyclone separator. The quantitative conveyor 350 is connected to the denitrification agent inlet of the pyrolysis reactor 310; The boiler system 400 includes a boiler body 410, the gas inlet of which is connected to the outlet of the pyrolysis reactor 310.

[0034] Specifically, ammonium carbamate, as a novel denitrification agent, is crushed to less than 3mm and stored in the novel denitrification agent silo 330. The crushed novel denitrification agent is then transported to the cyclone separator by the conveying fan 360. After the first gas-solid separation is completed in the first cyclone separator 340, the solid enters the metering conveyor 350 and enters the pyrolysis reactor 310 under the metering conveying of the metering conveyor 350, thereby completing the supply of the novel denitrification agent. The crushed and dried biomass is stored in the biomass silo 320. The crushed and dried biomass has a particle size of less than 1-3 cm and needs to be dried to a moisture content of less than 20%. When biomass needs to be supplied to the pyrolysis reactor 310, the operator can control the biomass silo 320 to add it to the pyrolysis reactor 310 in real time.

[0035] The flue gas from co-pyrolysis enters the boiler, creating a localized "fuel-rich, oxygen-poor" atmosphere, reducing NOx generation and its initial concentration. The pyrolysis gas directly enters the boiler body 410, reducing carbon emissions from the boiler body 410. The amount of pyrolysis gas is larger than that of NH3 used for denitrification, which can effectively solve the problem of uneven distribution of NH3 in the furnace and on the catalyst surface, preventing ammonia escape and reaction with H2SO4 at the tail end of the flue to block the reactor.

[0036] In some embodiments, a gas-solid separation system 370 is connected between the first cyclone separator 340 and the novel denitrification agent silo 330. The inlet of the gas-solid separation system 370 is connected to the gas outlet of the cyclone separator, the solid outlet of the gas-solid separation system 370 is connected to the feed inlet of the novel denitrification agent silo 330, and the gas outlet of the gas-solid separation system 370 is connected to the gas inlet of the boiler.

[0037] Understandably, after gas-solid separation by the first cyclone separator 340, the gas will be discharged from the first cyclone separator 340. However, the gas will inevitably carry ammonium carbamate debris, which will follow the gas into the gas-solid separation system 370 (the gas-solid separation system 370 used in thermal power is a relatively mature existing technology, and its specific structure will not be described in detail here). The solid debris will be discharged from the solid outlet of the gas-solid separation system 370 and re-enter the new denitrification agent silo 330. The conveying air will carry the denitrification agent that has not been separated by the gas-solid separation system 370 directly into the boiler body 410 as secondary air. The conveying air supplied by the conveying fan 360 can be nitrogen or compressed air, preferably compressed air.

[0038] In some embodiments, in order to ensure the complete pyrolysis of biomass and ammonium carbamate, the temperature of the pyrolysis reactor 310 is controlled at 250-350°C.

[0039] In some embodiments, the ratio of the processing capacity of the pyrolysis system 300 to the capacity of the boiler body 410 is controlled at 2-10 kg / MJ, that is, when the pyrolysis system 300 has a capacity of 200-1000 kg / h, the boiler capacity is 100 MW.

[0040] In some embodiments, such as Figure 4 As shown, when the boiler body 410 is configured as a micro-circulating fluidized bed, the tail end of the boiler body 410 is connected to the second cyclone separator 420, and the solid outlet of the second cyclone separator 420 is connected to the boiler body 410. like Figure 5 As shown, when the boiler body 410 is configured as a pulverized coal boiler, the tail end of the boiler body 410 is connected to the tail flue 430.

[0041] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0042] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0043] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0044] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0045] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0046] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A novel biomass baking coupled with a denitrification agent pyrolysis reactor, characterized in that, The enclosure includes a housing, on the inner wall of which a heating chamber is provided, and the heating chamber is connected to a medium inlet and a medium outlet. The chamber is equipped with a dual-shaft stirring system, which includes two hollow stirring cylinders rotatably connected to the inner wall of the chamber. Each hollow stirring cylinder is equipped with a spiral blade, and a heating device is installed inside the two hollow stirring cylinders.

2. The novel biomass baking coupled with denitrification agent pyrolysis reactor as described in claim 1, characterized in that, The heating device includes two heating rods respectively inserted into two hollow stirring cylinders. Both heating rods are hollow and connected by an arc-shaped pipe. The arc-shaped pipe and the two heating rods are arranged in a U-shape, and the arc-shaped pipe is connected to the heating chamber by a medium exchange port.

3. The novel biomass baking coupled with denitrification agent pyrolysis reactor as described in claim 2, characterized in that, The outer side of the box is equipped with an insulation layer.

4. The novel biomass baking coupled with denitrification agent pyrolysis reactor as described in claim 2, characterized in that, The heating medium in the heating chamber and the heating rod is either flue gas or heat transfer oil, and the heat transfer oil is either synthetic heat transfer oil or biphenyl-diphenyl ether mixture heat transfer oil.

5. The novel biomass baking coupled denitrification agent pyrolysis reactor as described in claim 4, characterized in that, The flue gas temperature is set to 500-600℃, and the heat transfer oil temperature is set to 300-400℃.

6. A system using a biomass baking coupled with a novel denitrification agent pyrolysis reactor as described in any one of claims 1 to 3, characterized in that, This includes pyrolysis systems and boiler systems; The pyrolysis system includes the pyrolysis reactor, which is connected to a biomass silo and a novel denitrification agent conveying component. The novel denitrification agent conveying component includes a novel denitrification agent silo, a first cyclone separator, and a quantitative conveyor connected sequentially along the novel denitrification agent conveying sequence. A conveying fan is connected to the outlet pipe of the novel denitrification agent silo, and the conveying direction of the conveying fan is from the outlet of the novel denitrification agent silo to the inlet of the cyclone separator. The quantitative conveyor is connected to the denitrification agent inlet of the pyrolysis reactor; The boiler system includes a boiler body, and the gas inlet of the boiler body is connected to the outlet of the pyrolysis reactor.

7. The system as described in claim 6, characterized in that, A gas-solid separation system is connected between the first cyclone separator and the novel denitrification agent silo. The inlet of the gas-solid separation system is connected to the gas outlet of the cyclone separator, the solid outlet of the gas-solid separation system is connected to the feed inlet of the novel denitrification agent silo, and the gas outlet of the gas-solid separation system is connected to the gas inlet of the boiler.

8. The system as described in claim 6, characterized in that, The temperature of the pyrolysis reactor is controlled at 250-350℃.

9. The system as described in claim 6, characterized in that, The ratio of the processing capacity of the pyrolysis system to the capacity of the boiler body is controlled at 2-10 kg / MJ.

10. The system as described in claim 6, characterized in that, When the boiler body is configured as a micro-circulating fluidized bed, the tail end of the boiler body is connected to a second cyclone separator, and the solid outlet of the second cyclone separator is connected to the boiler body. When the boiler body is configured as a pulverized coal boiler, the tail end of the boiler body is connected to the tail flue.

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