Method and system for denitration in solid waste treatment furnace

Abstract

The invention relates to the technical field of solid waste treatment, in particular to a denitration method and system in a solid waste treatment furnace, and the method comprises the following steps: detecting the mass of organic nitrogen in solid waste to be treated; adding an ammonia source substance with a preset mass into the to-be-treated solid waste to obtain a mixed material; and the mixed material is fed into a solid waste treatment furnace to be incinerated, nitric oxide generated in the incineration process is reduced by ammonia gas decomposed by the ammonia source substance in the solid waste treatment furnace, and denitration is achieved. Special denitration equipment is not needed, on-site denitration can be conducted in the solid waste treatment furnace, the follow-up denitration load is reduced, and the NOx emission index in flue gas emission is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of solid waste treatment, and in particular to a destocking method and system in a solid waste disposal furnace. Background Art

[0002] During the incineration process of solid waste, nitrogen oxides (NOx) with a certain concentration will be produced. According to relevant national environmental protection standards, the nitrogen oxides in the flue gas produced by incineration must be discharged in compliance with the standards.

[0003] Currently, common denitrification technologies are categorized as selective non-catalytic reduction (SNCR) and selective catalytic reduction (SCR). Regardless of which method is used, the denitrification process must be completed within specialized denitrification equipment (such as a denitrification tower). This undoubtedly increases the construction and subsequent maintenance costs of the denitrification equipment. Furthermore, when the organic nitrogen content in solid waste is high, the concentration of fuel-generated nitrogen oxides (NOx) increases dramatically. In this scenario, even with traditional single-stage SCR or SNCR denitrification processes, or even a two-stage SNCR+SCR denitrification process, the NOx content in the final flue gas still fails to meet emission standards.

[0004] Furthermore, as the country raises emission standards for solid waste incineration flue gas, a common technical modification measure to improve nitrogen oxide treatment is to add a first-stage SCR to the SNCR process. However, this modification not only significantly increases technical modification costs, but also further increases operating costs due to the need to reheat the flue gas during SCR operation. Summary of the Invention

[0005] The purpose of the present invention is to provide a denitrification method and system in a solid waste disposal furnace, which does not require special denitrification equipment and can denitrify on-site in the solid waste disposal furnace, reduce the subsequent denitrification load, and improve the NOx emission index in flue gas emissions.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides a method for removing nitrite in a solid waste disposal furnace, comprising: Detect the quality of organic nitrogen in solid waste to be treated; Adding a preset mass of ammonia source material to the solid waste to be treated to obtain a mixed material; The mixed material is sent to a solid waste disposal furnace for incineration. The nitrogen oxides generated during the incineration process are reduced by ammonia gas decomposed from the ammonia source material in the solid waste disposal furnace to achieve denitrification.

[0007] Furthermore, the ammonia source material includes at least one of urea, ammonium chloride, ammonium bicarbonate, ammonium sulfate and concentrated ammonia water.

[0008] Furthermore, the added amount of the ammonia source is 0.5 to 1.0 times the mass of the organic nitrogen.

[0009] Furthermore, a flue gas circulation component is provided in the solid waste disposal furnace, through which the incineration flue gas is circulated step by step from the head to the tail of the solid waste disposal furnace, and the flue gas is discharged through the tail; Alternatively, the flue gas circulation component is used to circulate the incineration flue gas from the tail end to the head end of the solid waste disposal furnace step by step, and the flue gas is discharged through the head end; Alternatively, the incineration flue gas is circulated step by step from the head and tail of the solid waste disposal furnace to the middle part through the flue gas circulation component, and the flue gas is discharged through the middle part.

[0010] Furthermore, the exhausted flue gas is sequentially subjected to dust removal, desulfurization, and deep denitrification treatment.

[0011] In a second aspect, the present invention provides a destocking system in a solid waste disposal furnace, comprising: A detection component for detecting the quality of organic nitrogen in the solid waste to be treated; A mixing component is used to add a preset mass of ammonia source material to the solid waste to be treated to obtain a mixed material; The solid waste disposal furnace is used to incinerate mixed materials. The nitrogen oxides generated during the incineration process are reduced by ammonia gas decomposed from the ammonia source material in the solid waste disposal furnace to achieve denitrification.

[0012] Furthermore, a flue gas circulation component is provided in the solid waste disposal furnace, through which the incineration flue gas is circulated step by step from the head to the tail of the solid waste disposal furnace, and the flue gas is discharged through the tail; Alternatively, the flue gas circulation component is used to circulate the incineration flue gas from the tail end to the head end of the solid waste disposal furnace step by step, and the flue gas is discharged through the head end; Alternatively, the incineration flue gas is circulated step by step from the head and tail of the solid waste disposal furnace to the middle part through the flue gas circulation component, and the flue gas is discharged through the middle part.

[0013] The present invention has the following unexpected beneficial effects: the present invention obtains a mixed material by adding a preset mass of ammonia source material to the solid waste to be treated; the mixed material is then sent to a solid waste disposal furnace for incineration treatment, and the nitrogen oxides generated during the incineration process are reduced by ammonia gas decomposed by the ammonia source material in the solid waste disposal furnace, thereby achieving denitrification. Furthermore, no additional special denitrification equipment is required, and denitrification can be achieved in the solid waste disposal furnace, avoiding the cost of building equipment such as denitrification towers, reducing initial investment and long-term maintenance costs. In addition, during the incineration process, since the ammonia gas decomposed by the ammonia source material can reduce nitrogen oxides in the furnace, the amount of nitrogen oxides entering the subsequent flue gas purification system is reduced, which greatly reduces the burden of subsequent treatment and improves the overall denitrification efficiency. In addition, the amount of ammonia source material added is determined based on the mass of organic nitrogen in the solid waste and can be flexibly adjusted according to the actual situation of the solid waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the implementation methods or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention.

[0015] Figure 1 A schematic flow chart of a denitrification method in a solid waste disposal furnace according to an embodiment of the present invention is shown.

[0016] Figure 2 A structural schematic diagram of an implementation scheme of a destocking system in a solid waste disposal furnace according to an embodiment of the present invention is shown.

[0017] Figure 3 A structural schematic diagram of another embodiment of the denitrification system in the solid waste disposal furnace according to an embodiment of the present invention is shown.

[0018] Figure 4 A structural schematic diagram of another embodiment of the denitrification system in the solid waste disposal furnace according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0019] The following describes the embodiments of the present invention with reference to the accompanying drawings and preferred embodiments. Those skilled in the art will readily appreciate the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the various details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are intended only to illustrate the present invention and are not intended to limit the scope of protection of the present invention.

[0020] It should be noted that the illustrations provided in the following embodiments are merely schematic illustrations of the basic concept of the present invention. The illustrations only show components related to the present invention and are not drawn according to the number, shape, and size of components in actual implementation. In actual implementation, the type, quantity, and proportion of each component may be changed arbitrarily, and the component layout may also be more complex.

[0021] In one embodiment, see Figure 1 As shown, the present invention provides a method for removing the solid waste in a solid waste disposal furnace, which includes: S1, detect the quality of organic nitrogen in the solid waste to be treated.

[0022] S2, adding a preset mass of ammonia source material to the solid waste to be treated to obtain a mixed material.

[0023] S3, the mixed material is sent to the solid waste disposal furnace for incineration. The nitrogen oxides generated during the incineration process are reduced by ammonia gas decomposed by the ammonia source material in the solid waste disposal furnace to achieve denitrification.

[0024] Existing selective non-catalytic denitration (SNCR) and selective catalytic denitration (SCR) methods both require specialized denitration equipment (such as denitration towers), which are costly to build and maintain. This invention eliminates the need for specialized denitration equipment and can achieve denitration within the solid waste disposal furnace, eliminating the expense of building denitration towers and other equipment, reducing both initial investment and long-term maintenance costs.

[0025] When solid waste contains high levels of organic nitrogen, traditional single-stage or two-stage denitrification methods struggle to achieve standard nitrogen oxide emissions. During the incineration process, the present invention uses ammonia generated by the decomposition of an ammonia source to reduce nitrogen oxides within the furnace, reducing the amount of nitrogen oxides entering the subsequent flue gas purification system. Furthermore, the amount of ammonia source added is determined by the mass of organic nitrogen in the solid waste and can be flexibly adjusted based on the actual conditions of the solid waste.

[0026] As national emission standards increase, traditional technical improvement measures to improve nitrogen oxide treatment efficiency are costly. This invention, without adding new denitrification equipment, effectively reduces nitrogen oxide emission concentrations through in-furnace denitrification combined with subsequent treatment processes.

[0027] As a preferred embodiment of the present invention, the ammonia source material includes at least one of urea, ammonium chloride, ammonium bicarbonate, ammonium sulfate and concentrated ammonia water.

[0028] A variety of ammonia sources are available, allowing for flexible adaptation to varying solid waste characteristics and incineration conditions. For example, urea offers greater stability, making it easier to store and add, while ammonium chloride may offer higher denitrification efficiency at certain incineration temperatures. For higher solid waste incineration temperatures, urea, with its excellent thermal stability, may be an option. For lower incineration temperatures, ammonia sources with lower decomposition temperatures, such as ammonium chloride, may be more suitable.

[0029] The costs of different ammonia sources vary. Concentrated aqueous ammonia is relatively cheap and can be used as an ammonia source when cost control is stringent and denitrification requirements are met. While urea may be slightly more expensive, its combined denitrification effectiveness and stability make it more advantageous in applications requiring high denitrification efficiency and operational ease. This provides companies with flexibility in selecting the appropriate ammonia source based on their financial strength and production needs.

[0030] Different ammonia sources decompose at varying rates and in varying amounts. Using a combination of these sources can provide a continuous and appropriate concentration of ammonia at different stages of the incineration process, ensuring adequate reduction of nitrogen oxides. For example, ammonium bicarbonate decomposes quickly, providing a rapid supply of ammonia during the initial stages of incineration, while ammonium sulfate decomposes more slowly, providing a continuous supply of ammonia during the later stages of incineration, both ensuring effective denitrification.

[0031] As a preferred embodiment of the present invention, the added amount of the ammonia source is 0.5 to 1.0 times the mass of the organic nitrogen.

[0032] During the incineration process, organic nitrogen in solid waste is converted into nitrogen oxides. Ammonia produced by the decomposition of ammonia-derived substances undergoes a reduction reaction with these nitrogen oxides to achieve denitrification. An addition level of 0.5 to 1.0 times the mass of organic nitrogen provides sufficient ammonia to react with the nitrogen oxides. If the amount of ammonia-derived substance added is excessive, exceeding 1.0 times the mass of organic nitrogen, the excess ammonia source will not fully participate in the denitrification reaction, resulting in material waste and increased production costs. Staying within this addition range ensures effective denitrification while avoiding unnecessary resource waste. Furthermore, excessive ammonia-derived substances may produce other byproducts during incineration, or unreacted ammonia may be emitted with the flue gas, causing secondary pollution. Keeping the addition level within a reasonable range can effectively mitigate this risk and make the entire solid waste incineration denitrification process more environmentally friendly.

[0033] As a preferred embodiment of the present invention, see Figures 2 to 4 As shown, the solid waste disposal furnace is provided with a flue gas circulation component, see Figure 2 As shown, the incineration flue gas is circulated step by step from the head to the tail of the solid waste disposal furnace through the flue gas circulation component, and the flue gas is discharged through the tail.

[0034] Alternatively, see Figure 3 As shown, the incineration flue gas is circulated step by step from the tail end to the head end of the solid waste disposal furnace through the flue gas circulation component, and the flue gas is discharged through the head end.

[0035] Alternatively, see Figure 4 As shown, the flue gas circulation component circulates the incineration flue gas from the head and tail of the solid waste disposal furnace to the middle step by step, and the flue gas is discharged through the middle.

[0036] The flue gas recirculation component circulates the incineration flue gas within the solid waste disposal furnace, either from the beginning to the end, the end to the beginning, or from the beginning and end to the middle. This prolongs the flue gas's residence time within the furnace. This allows the ammonia produced by the decomposition of the ammonia source more time to fully contact and react with nitrogen oxides, thereby improving denitrification efficiency. For example, during the circulation process, nitrogen oxides that might otherwise not fully react due to excessive flow have more opportunities to combine with ammonia and be reduced to harmless substances.

[0037] During the circulation process, the nitrogen oxides and ammonia in the flue gas are more evenly distributed, avoiding the situation where the concentration of reactants is too high or too low in some areas. The uniform mixing state helps to improve the completeness of the reaction, making the denitrification reaction more efficient throughout the furnace.

[0038] Furthermore, the incineration flue gas carries a significant amount of heat, which can be reused multiple times within the furnace through flue gas circulation. When the flue gas is circulated back into the furnace, its heat provides energy for subsequent incineration and denitrification reactions, reducing additional energy consumption and lowering operating costs. For example, during the process of circulating from the tail to the head, the high-temperature flue gas discharged from the tail can preheat the newly entering mixture, improving incineration efficiency.

[0039] This in-furnace flue gas recirculation method can, to a certain extent, replace or reduce reliance on complex external denitrification equipment. Traditional denitrification equipment requires additional energy to operate, but achieving denitrification through in-furnace recirculation can reduce the demand for this equipment, thereby reducing equipment construction and maintenance costs.

[0040] See also Figures 2 to 4 As shown, the present invention provides three different flue gas circulation methods, which can be flexibly selected according to factors such as the characteristics of the solid waste, the incineration conditions, and the initial concentration of nitrogen oxides. For solid wastes of different compositions and properties, different circulation methods may produce different denitrification effects. For example, when the organic nitrogen content in the solid waste is high and the concentration of nitrogen oxides produced is large, a circulation method that is more conducive to full reaction can be selected, such as circulation from the head and tail to the middle, to ensure a better denitrification effect. And as environmental protection standards continue to improve, this flexible circulation method can be easily adjusted and optimized to adapt to new emission requirements. When emission standards become more stringent, the denitrification efficiency can be further improved by adjusting parameters such as the cycle sequence and the number of cycles to ensure that nitrogen oxides in the flue gas meet emission standards.

[0041] As a preferred embodiment of the present invention, the exhausted flue gas is subjected to dust removal, desulfurization, and deep denitrification treatment in sequence.

[0042] In addition to nitrogen oxides, solid waste incineration also produces pollutants such as dust and sulfur dioxide. A sequential approach of dust removal, desulfurization, and advanced denitrification can comprehensively remove these pollutants, ensuring that the final flue gas emissions meet strict environmental standards. For example, dust removal effectively removes particulate matter from flue gas, reducing dust pollution in the atmosphere; desulfurization reduces sulfur dioxide levels, preventing environmental problems such as acid rain; and advanced denitrification further reduces nitrogen oxide concentrations, meeting increasingly stringent nitrogen oxide emission requirements and comprehensively safeguarding air quality.

[0043] The various pollutant removal processes work together to enhance overall treatment effectiveness. Initial dust removal prevents dust from clogging and wearing subsequent desulfurization and denitrification equipment, ensuring proper operation and improving treatment efficiency. The desulfurization process reduces sulfur dioxide interference with the denitrification reaction, creating more favorable conditions for deep denitrification. Deep denitrification further purifies the flue gas that has undergone preliminary denitrification in the solid waste disposal furnace, ensuring consistent compliance with nitrogen oxide emissions standards. The entire process forms an integrated whole, ensuring more stable and reliable flue gas treatment.

[0044] Pre-emptive dust removal and desulfurization can effectively reduce the corrosion of dust and sulfur dioxide on subsequent deep denitrification equipment. Dust can exacerbate mechanical wear on equipment, while sulfur dioxide, when in contact with water, forms acidic substances that corrode metal components. Preemptive removal of these harmful substances can extend the service life of deep denitrification equipment, reduce equipment maintenance and replacement costs, and improve the company's economic benefits.

[0045] With evolving environmental protection requirements and regional differences, this sequential treatment approach is highly adaptable. Companies can flexibly adjust process parameters and equipment configurations for each treatment step based on local environmental standards and actual conditions. For example, in regions with particularly stringent NOx emission requirements, deep denitrification can be strengthened; in areas with severe dust pollution, dust removal efforts can be increased to meet environmental protection needs in different scenarios.

[0046] In another embodiment, the present invention provides a destocking system in a solid waste disposal furnace, see Figure 2 As shown, the system includes a detection component 1, a mixing component 2, and a solid waste disposal furnace 3. The detection component 1 is used to detect the mass of organic nitrogen in the solid waste to be treated. The mixing component 2 is used to add a preset mass of ammonia source material to the solid waste to be treated, and then stir and mix to obtain a mixed material. The ammonia source material is pre-stored in a storage bin 4. The solid waste disposal furnace 3 is used to incinerate the mixed material. The nitrogen oxides generated during the incineration process are reduced by ammonia gas decomposed by the ammonia source material in the solid waste disposal furnace, achieving denitrification.

[0047] As a preferred embodiment of the present invention, the denitrification system in the solid waste disposal furnace of the present invention also includes a flue gas post-treatment device 5. Specifically, the inlet of the flue gas post-treatment device 5 is connected to the flue gas exhaust port of the solid waste disposal furnace 3, and is used to perform dust removal, desulfurization, and deep denitrification treatment on the exhausted flue gas in sequence.

[0048] The above embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Any equivalent substitution or modification made by those skilled in the art based on the present invention is within the protection scope of the present invention.

Claims

1. A method for removing solid waste from a solid waste disposal furnace, characterized in that: include: Detect the quality of organic nitrogen in solid waste to be treated; Adding a preset mass of ammonia source material to the solid waste to be treated to obtain a mixed material; The mixed material is sent to a solid waste disposal furnace for incineration. The nitrogen oxides generated during the incineration process are reduced by ammonia gas decomposed from the ammonia source material in the solid waste disposal furnace to achieve denitrification.

2. The method for removing the slag in a solid waste disposal furnace according to claim 1, characterized in that: The ammonia source material includes at least one of urea, ammonium chloride, ammonium bicarbonate, ammonium sulfate and concentrated ammonia water.

3. The method for removing the nitrate in a solid waste disposal furnace according to claim 1, characterized in that: The added amount of the ammonia source material is 0.5 to 1.0 times the mass of the organic nitrogen.

4. The method for removing the slag in a solid waste disposal furnace according to claim 1, characterized in that: The solid waste disposal furnace is provided with a flue gas circulation component, through which the incineration flue gas is circulated step by step from the head to the tail of the solid waste disposal furnace, and the flue gas is discharged through the tail; Alternatively, the flue gas circulation component is used to circulate the incineration flue gas from the tail end to the head end of the solid waste disposal furnace step by step, and the flue gas is discharged through the head end; Alternatively, the incineration flue gas is circulated step by step from the head and tail of the solid waste disposal furnace to the middle part through the flue gas circulation component, and the flue gas is discharged through the middle part.

5. The method for removing the nitrate in a solid waste disposal furnace according to claim 4, characterized in that: The exhaust flue gas is subjected to dust removal, desulfurization and deep denitrification treatment in sequence.

6. A destocking system in a solid waste disposal furnace, characterized in that: include: A detection component for detecting the quality of organic nitrogen in the solid waste to be treated; A mixing component is used to add a preset mass of ammonia source material to the solid waste to be treated to obtain a mixed material; The solid waste disposal furnace is used to incinerate mixed materials. The nitrogen oxides generated during the incineration process are reduced by ammonia gas decomposed from the ammonia source material in the solid waste disposal furnace to achieve denitrification.

7. The destocking system in a solid waste disposal furnace according to claim 6, characterized in that: The solid waste disposal furnace is provided with a flue gas circulation component, through which the incineration flue gas is circulated step by step from the head to the tail of the solid waste disposal furnace, and the flue gas is discharged through the tail; Alternatively, the flue gas circulation component is used to circulate the incineration flue gas from the tail end to the head end of the solid waste disposal furnace step by step, and the flue gas is discharged through the head end; Alternatively, the incineration flue gas is circulated step by step from the head and tail of the solid waste disposal furnace to the middle part through the flue gas circulation component, and the flue gas is discharged through the middle part.

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