Environment-friendly treatment system for high-concentration nitrogen oxide organic waste gas

Abstract

The utility model discloses a high-concentration nitrogen oxide organic waste gas environment-friendly treatment system, which relates to the technical field of waste gas environment-friendly treatment and comprises a reduction furnace and an oxidation furnace, the oxidation furnace is positioned below the reduction furnace, a reduction furnace combined burner is arranged at the upper end of the reduction furnace, and a reducing agent bin is arranged on the right side of the reduction furnace. An oxidation furnace integrated combustor is arranged on the left side of the oxidation furnace, a waste heat boiler is arranged on the right side of the oxidation furnace, and an outlet of the waste heat boiler is sequentially connected with a bag-type dust collector and a chimney through a flue. The denitration system disclosed by the utility model is simple and efficient, does not need a catalyst, provides energy by utilizing the combustion of natural gas, and can reach 99% in denitration efficiency through the reaction of the powdery carbonaceous reducing agent and nitric oxide. The reducing agent is low in cost and suitable for high-concentration nitrogen oxide waste gas treatment. The oxidation furnace is arranged to ensure that environmental protection reaches the standard, and a waste heat recovery device reduces operation cost. In general, the system has the multiple advantages of being simple, efficient, low in cost, environmentally friendly, capable of saving energy and the like.

Description

Technical Field

[0001] The utility model relates to the technical field of waste gas environmental protection treatment, in particular to an environmental protection treatment system for high-concentration nitrogen oxide organic waste gas. Background Technique

[0002] Nitrogen oxides mainly include nitric oxide, nitrogen dioxide, dinitrogen monoxide, dinitrogen trioxide, dinitrogen tetroxide, dinitrogen pentoxide, etc. Except for nitric oxide and nitrogen dioxide, other nitrogen oxides are unstable and are easily converted into nitric oxide and nitrogen dioxide. Therefore, generally, nitrogen oxides are the general term for nitric oxide and nitrogen dioxide, represented by NOx.

[0003] Nitrogen oxides are a major air pollutant, and long-term exposure causes great harm to the human body. It mainly harms the respiratory mucosa and tissues of the human body, especially the lungs are significantly damaged. In severe cases, lesions mainly characterized by pulmonary edema may occur. Nitrogen oxides discharged into the atmosphere will also cause acid rain. When rainwater falls into rivers, lakes and enters the water cycle, it will cause eutrophication of water bodies, leading to soil acidification and ecological system imbalance. Therefore, nitrogen oxides are included in various air pollutant emission standards, and the emission standards are becoming increasingly strict.

[0004] The process technologies for removing nitrogen oxides are collectively referred to as denitrification technologies. Currently, the mainstream denitrification technologies include selective catalytic reduction denitrification (SCR), selective non-catalytic reduction denitrification (SNCR), ozone advanced oxidation denitrification, and alkali solution absorption method denitrification, etc.

[0005] SCR denitrification is the most mainstream denitrification technology at present. Using a special denitrification catalyst, ammonia generated by the reductant sprayed into the flue gas selectively reacts with nitrogen oxides under the action of the catalyst to reduce nitrogen oxides into nitrogen and water. The biggest advantage of this technology is its high denitrification efficiency. Theoretically, the denitrification efficiency can be close to 100%. However, SCR denitrification also has many disadvantages. It requires a catalyst and a reductant. The catalyst is made of precious metals, with a high price, a short service life, and is prone to poisoning. The used catalyst belongs to hazardous waste and requires special treatment; when the concentration of nitrogen oxides in the flue gas is high, more reductant needs to be consumed, and the operating cost is high.

[0006] The SNCR denitrification process is simple. The reductant is sprayed into the flue gas, and ammonia generated by the reductant can react with nitrogen oxides to reduce nitrogen oxides into nitrogen and water. SNCR denitrification does not require a catalyst, but its denitrification efficiency is low, generally not exceeding 50%, and there is a risk of ammonia escape, so it needs to be used in combination with other denitrification technologies. According to the type of reductant, SNCR denitrification must heat the flue gas temperature to 900°C - 1100°C, which consumes fuel, so it can only be an auxiliary denitrification technology.

[0007] Ozone advanced oxidation denitration uses ozone to oxidize nitric oxide in nitrogen oxides into nitrogen dioxide, and then utilizes the property that nitrogen dioxide is easily soluble in water to remove nitrogen oxides in flue gas by washing with water or alkali washing. This method consumes ozone, and currently, ozone is mainly produced by converting pure oxygen into ozone through high-voltage discharge, with high energy consumption and cost, and is not suitable for the treatment of high-concentration nitrogen oxide waste gas.

[0008] The alkali solution absorption method utilizes that nitrogen oxides are acidic gases and can undergo acid-base neutralization reactions with alkali solutions. An alkali solution is sprayed into the waste gas to absorb nitrogen oxides, generating nitrates and nitrites. This method is mostly used in combination with the advanced oxidation method because nitric oxide does not react with sodium hydroxide alone and can only react with sodium hydroxide together with nitrogen dioxide. However, the content of nitric oxide in the nitrogen oxides generated by combustion is relatively high, reaching more than 90%, so its application is limited. If the concentration of nitrogen oxides is high, the consumption of the alkali solution is also large, and the generated nitrate and nitrite solutions still need to be treated, resulting in relatively high operating costs.

[0009] For nitrogen oxide waste gas, a thermal carbon reduction technology can also be used to achieve it. For example, the authorized patent CN200410073020.8, a fine coal powder reburning denitration method, includes a furnace body of a coal-fired boiler and pipelines, dampers, distributors, adjustable throttles, headers, etc. connecting various equipment. A coarse powder separator is used to improve the overall fineness and uniformity of the coal powder; the burners installed on the furnace wall include a main burner, a reburning fuel burner, and an overfire air nozzle. Among them, the main burner is located in the main combustion zone inside the furnace body, the reburning fuel burner is located in the reburning zone, and the overfire air nozzle is located in the burnout zone; a furnace gas fan is used to extract flue gas from the tail flue to transport the reburning coal powder. Utility Model Content

[0010] The purpose of the present utility model is to provide an environmental protection treatment system for high-concentration nitrogen oxide organic waste gas to solve the problems raised in the above background technology. To achieve the above purpose, the present utility model provides the following technical solution: An environmental protection treatment system for high-concentration nitrogen oxide organic waste gas includes a reduction furnace and an oxidation furnace. The oxidation furnace is located below the reduction furnace. The upper end of the reduction furnace is provided with a reduction furnace combined burner, and waste gas and natural gas enter through the upper end of the reduction furnace combined burner. A reductant bin is provided on the right side of the reduction furnace, and a reductant pneumatic conveyor is provided below the reductant bin to lead into the reduction furnace. An oxidation furnace integrated burner is provided on the left side of the oxidation furnace, and a waste heat boiler is provided on the right side of the oxidation furnace. The outlet of the waste heat boiler is connected to a bag filter and a chimney in sequence through a flue.

[0011] Preferably: A reduction furnace make-up air blower is provided on the side of the reduction furnace combined burner.

[0012] Furthermore, a steam drum and a high-temperature economizer are provided above the waste heat boiler, and a low-temperature economizer is provided between the bag filter and the chimney.

[0013] Preferably, an inlet pipe of the low-temperature economizer is connected to a boiler feed water tank, an outlet of the low-temperature economizer is connected to an inlet of the high-temperature economizer through a pipe, and an outlet of the high-temperature economizer is connected above the steam drum through a pipe.

[0014] Preferably, a boiler feed water pump is provided on the pipe between the boiler feed water tank and the low-temperature economizer.

[0015] Preferably, an induced draft fan is provided on the inlet flue below the chimney.

[0016] This system uses powdered carbonaceous materials (activated carbon powder, fruit pit carbon powder, anthracite, coke, etc.) as reducing agents, which can undergo reduction reactions with nitrogen monoxide and nitrogen dioxide at high temperatures to reduce nitrogen oxides to nitrogen and carbon dioxide. The reaction principle is as follows:

[0017] 2NO + C = CO2 + N2

[0018] 2NO2 + 2C = 2CO2 + N2

[0019] This method does not require a catalyst, the reducing agent is inexpensive, both nitrogen monoxide and nitrogen dioxide can react, no secondary wastewater is produced, and the operating cost is relatively low.

[0020] Compared with the prior art, the beneficial effects of the present utility model are as follows: 1) The system process of the present utility model is simple, does not require a catalyst, uses natural gas combustion to provide reaction energy, and the heat released by the reduction reaction during normal operation can maintain the temperature of the reduction furnace at 650 - 850 °C, reducing fuel consumption.

[0021] 2) The denitration efficiency of the present utility model is high. The residence time of the waste gas in the reduction furnace is > 10 seconds, and the powdered carbonaceous material can undergo reduction reactions with nitrogen oxides in the reduction furnace, enabling the denitration reaction to proceed fully. The highest denitration efficiency can reach about 99%.

[0022] 3) The denitration reducing agent of the present utility model uses powdered carbonaceous materials (activated carbon powder, fruit pit carbon powder, anthracite, coke, etc.), which are inexpensive and are particularly suitable for the denitration treatment of high-concentration nitrogen oxide organic waste gas, with low operating costs.

[0023] 4) The present utility model is provided with an oxidation furnace, and the operating temperature of the oxidation furnace is 1100 - 1200 °C, which can completely incinerate the harmful substances escaping from the reduction furnace and the unreacted powdered carbonaceous material, meeting the environmental protection standards.

[0024] 5) The present utility model is provided with a waste heat recovery device to recover the waste heat of the high-temperature flue gas of the oxidation furnace to generate steam revenue, further reducing the operating cost. Description of the Drawings

[0025] Figure 1 This is a schematic layout diagram of the present utility model.

[0026] In the figure: 1. Reduction furnace combined burner; 2. Oxidation furnace integrated burner; 3. Reduction furnace; 4. Oxidation furnace; 5. Waste heat boiler; 6. Steam drum; 7. High-temperature economizer; 8. Bag filter; 9. Low-temperature economizer; 10. Induced draft fan; 11. Chimney; 12. Reduction furnace make-up air fan; 13. Reducing agent bin; 14. Reducing agent pneumatic conveyor; 15. Boiler feed water tank; 16. Boiler feed water pump. Detailed Embodiments

[0027] The following will describe the present utility model in conjunction with the drawings in the embodiments of the present utility model. It should be noted that the present utility model is not limited to these embodiments. In the following detailed description of the present utility model, some specific details are described in detail. However, those skilled in the art can also fully understand the present utility model for the parts that are not described in detail.

[0028] In addition, those of ordinary skill in the art should understand that the provided drawings are only for illustrating the purpose, features, and advantages of the present utility model, and the drawings are not actually drawn to scale.

[0029] At the same time, unless the context clearly requires otherwise, the words "including", "comprising", and similar words in the entire specification and claims should be interpreted as having the meaning of inclusion rather than exclusion or exhaustion; that is, the meaning of "including but not limited to".

[0030] Please refer to Figure 1 , the present utility model provides a technical solution: including a reduction furnace 3 and an oxidation furnace 4. The oxidation furnace 4 is located below the reduction furnace 3. The upper end of the reduction furnace 3 is provided with a reduction furnace combined burner 1. Exhaust gas and natural gas enter through the upper end of the reduction furnace combined burner 1. A reducing agent bin 13 is provided on the right side of the reduction furnace 3. A reducing agent pneumatic conveyor 14 is provided below the reducing agent bin 13 leading to the inside of the reduction furnace 3. An oxidation furnace integrated burner 2 is provided on the left side of the oxidation furnace 4. A waste heat boiler 5 is provided on the right side of the oxidation furnace 4. The outlet of the waste heat boiler 5 is sequentially connected with a bag filter 8 and a chimney 11 through a flue.

[0031] A reduction furnace make-up air fan 12 is provided on the side of the reduction furnace combined burner 1.

[0032] A steam drum 6 and a high-temperature economizer 7 are provided above the waste heat boiler 5. A low-temperature economizer 9 is provided between the bag filter 8 and the chimney 11.

[0033] The inlet pipe of the low-temperature economizer 9 is connected to a boiler feed water tank 15. The outlet of the low-temperature economizer 9 is connected to the inlet of a high-temperature economizer 7 through a pipe, and the outlet of the high-temperature economizer 7 is connected above a steam drum 6 through a pipe.

[0034] A boiler feed water pump 16 is provided on the pipe between the boiler feed water tank 15 and the low-temperature economizer 9.

[0035] An induced draft fan 10 is provided on the inlet flue below the chimney 11.

[0036] When the present utility model is in use, the reduction furnace combined burner 1 and the oxidation furnace integrated burner 2 are fed with natural gas for ignition by spraying fire. Powdered carbonaceous materials (activated carbon powder, fruit pit carbon powder, anthracite, coke, etc.) are sprayed into the reduction furnace 3 through a reductant pneumatic conveyor 14 in a reductant bin 13. At the same time, waste gas is introduced from the upper end of the reduction furnace combined burner 1, and combustion reduction treatment begins. At high temperatures, it can undergo a reduction reaction with nitrogen monoxide and nitrogen dioxide to reduce nitrogen oxides to nitrogen and carbon dioxide. The reaction principle is as follows:

[0037] 2NO + C = CO2 + N2

[0038] 2NO2 + 2C = 2CO2 + N2

[0039] The hot flue gas after the reaction undergoes heat recovery in a waste heat boiler 5, and then undergoes dust treatment in a bag filter 8. After reaching the standard, it is discharged. Above the waste heat boiler 5, a high-temperature economizer 7 and a low-temperature economizer 9 are provided at the outlet of the bag filter 8 for combined heat recovery. The boiler feed water tank 15 provides water sources for the two economizers, and then steam will enter the steam drum 6 for recycling.

[0040] Although embodiments of the present utility model have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principle and spirit of the present utility model. The scope of the present utility model is defined by the appended claims and their equivalents.

Claims

1. An environmental protection treatment system for high-concentration nitrogen oxide organic waste gas, characterized in that: It includes a reduction furnace (3) and an oxidation furnace (4). The oxidation furnace (4) is located below the reduction furnace (3). The upper end of the reduction furnace (3) is provided with a reduction furnace combined burner (1). Waste gas and natural gas enter through the upper end of the reduction furnace combined burner (1). A reducing agent bin (13) is provided on the right side of the reduction furnace (3). A reducing agent pneumatic conveyor (14) is provided below the reducing agent bin (13) and leads to the inside of the reduction furnace (3). An oxidation furnace integrated burner (2) is provided on the left side of the oxidation furnace (4). A waste heat boiler (5) is provided on the right side of the oxidation furnace (4). The outlet of the waste heat boiler (5) is sequentially connected with a bag filter (8) and a chimney (11) through a flue.

2. The environmental protection treatment system for high-concentration nitrogen oxide organic waste gas according to claim 1, characterized in that: A reduction furnace make-up air blower (12) is provided on the side of the reduction furnace combined burner (1).

3. The environmental protection treatment system for high-concentration nitrogen oxide organic waste gas according to claim 1, characterized in that: A steam drum (6) and a high-temperature economizer (7) are provided above the waste heat boiler (5). A low-temperature economizer (9) is provided between the bag filter (8) and the chimney (11).

4. The environmental protection treatment system for high-concentration nitrogen oxide organic waste gas according to claim 3, characterized in that: The inlet pipe of the low-temperature economizer (9) is connected with a boiler feed water tank (15). The outlet of the low-temperature economizer (9) is connected with the inlet of the high-temperature economizer (7) through a pipe. The outlet of the high-temperature economizer (7) is connected above the steam drum (6) through a pipe.

5. The environmental protection treatment system for high-concentration nitrogen oxide organic waste gas according to claim 4, characterized in that: A boiler feed water pump (16) is provided on the pipe between the boiler feed water tank (15) and the low-temperature economizer (9).

6. The environmental protection treatment system for high-concentration nitrogen oxide organic waste gas according to claim 1, characterized in that: An induced draft fan (10) is provided on the inlet flue below the chimney (11).

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