CN105861816A - A Synergistic Emission Reduction Method of SO2 and Dioxin in Sintering Process Based on Adding Solid Inhibitor - Google Patents

Abstract

The present invention discloses a solid inhibitor addition based method for collaborative emission reduction of SO2 and dioxins in sintering process, and belongs to the technical field emissions of pollutants reduction in the sintering process. The present invention comprises the steps of: step 1, sintering cloth (A) paving a pavement material layer on the upper part of a sintering trolley, (B) paving a first mixture layer on the top of the pavement material layer, (C) mixing solid ammonia inhibitor granules with a sinter mixture, and paving a collaborative emission reduction material layer over the first mixture layer, and (D) paving a second mixture layer over the collaborative emission reduction material layer; and step 2, flue concentrated collection and treatment: emerging the flue gas in a bellows at the middle rear part of the sintering trolley into a bag dust remover by a booster pump, and introducing the flue gas after dust removal into a main flue collector by a pipe. Through addition of urea granules in the collaborative emission reduction material layer, the method achieves collaborative emission reduction of SO2 and dioxins in the sintering process on the premise of unchanged sinter quality, and greatly reduces the emission reduction burden of steel companies.

Description

A Synergistic Emission Reduction Method of SO2 and Dioxin in Sintering Process Based on Adding Solid Inhibitor

technical field

The invention relates to the technical field of pollutant emission reduction in the sintering process, and more specifically relates to a method for synergistic emission reduction of SO ₂ and dioxins in the sintering process based on the addition of solid inhibitors.

Background technique

The sintering process is an important process in the production chain of iron and steel complexes. With the rapid development of the iron and steel industry, the demand for iron ore is increasing day by day. However, there are fewer and fewer rich ores that are directly put into the furnace for ironmaking, and a large amount of lean ore resources must be mined and used. Smelting lean ore directly into the furnace will deteriorate the production index of the blast furnace. Therefore, lean ore is processed to obtain concentrate powder through mineral processing. The fine ore produced during the mining and processing of concentrate and rich ore needs to be agglomerated before it can be used in blast furnace ironmaking. The function of the sintering machine is to agglomerate fine ore. The metallurgical properties of the sintered minerals are greatly improved, bringing huge economic benefits to blast furnace production. Moreover, the sintering method has strong adaptability to raw materials. It can not only produce sintered ore with coarse-grained rich ore powder and concentrate powder, but also process industrial iron-containing waste.

However, while the sintering process provides a good input for the blast furnace, it also brings huge environmental pollution. Among them, SO ₂ is one of the important pollutants in the sintering process, and the SO ₂ discharged from the sintering process accounts for about 85% of the total SO ₂ emissions in steel production. The sintering desulfurization methods in the prior art are mainly for the terminal treatment of sintering flue gas. They are mainly divided into dry method, semi-dry method and wet method. Although most of them can effectively remove SO ₂ , the investment cost and operating cost Huge, easy to produce secondary pollution, and it is a single pollutant absorption desulfurization method, it is difficult to achieve coordinated emission reduction of multiple pollutants. Therefore, it is imperative to innovate the existing pollutant emission reduction methods.

In addition, in addition to SO ₂ , dioxin is another most important pollutant; compared with SO ₂ , dioxin is more harmful to human health and the natural environment, it is difficult to degrade in the natural environment, and can be distributed globally long-distance migration. Once dioxin is released into the air, it is difficult to degrade and eliminate naturally. Its toxicity is 130 times that of cyanide and 900 times that of arsenic. It is known as the "poison of the century"; It is concentrated and amplified along the food chain, which is extremely harmful to humans and animals. It not only has carcinogenic, teratogenic, and mutagenic properties, but also has endocrine disrupting effects. Studies have shown that the impact of persistent organic pollutants on humans will last for several generations, posing a major threat to human survival, reproduction and sustainable development.

The sintering process is a production unit that produces more dioxin-like pollutants, and dioxins produced by sintering account for about 17.6% of the total emissions. The sintering mixture is distributed on the sintering trolley, and after being ignited by the ignition furnace, it moves slowly with the trolley, and the air passes through the material layer from top to bottom, and the heat energy generated by combustion sinters or melts the mixture in the combustion layer. Sintering has most of the conditions for de novo synthesis: (1) Chlorine comes from recovered dust, slag and organic chlorine components in iron ore; (2) Carbon comes from carbon fiber, lignin, coke, vinyl, etc.; (3) Graphite structure with deformation and vacancy, inorganic chloride, copper and iron metal ions, as a catalyst; (4) Oxidizing atmosphere, the temperature is 250–450 °C.

In addition, in the process of producing sinter ore in iron and steel enterprises, since the sintering raw materials are recycled and utilized solid waste in the enterprise (such as steelmaking OG mud, blast furnace ash, etc.), some heavy metals are inevitably recovered during the sintering process, such as heavy metal Cu, Pt, Zn, Hg, etc., and these heavy metals (such as Cu) just play a catalytic role in the reaction of dioxin precursors (such as polychlorinated phenol and diphenyl ether) to generate dioxins, and promote the formation of dioxins. generation. Moreover, in order to reduce the low-temperature reduction pulverization rate of sintered ore, _CaCl2 dilute solution is often sprayed on the finished sintered ore. Although the purpose of improving the metallurgical properties of sintered ore is achieved, it also provides "providing for the formation of dioxins in the sintering process." Chlorine source" creates material conditions for its generation. In Europe, iron ore sintering is considered to be the second largest source of toxic pollutant emissions after municipal waste incinerators. Moreover, on November 4, 2010, my country specially released the "Guiding Opinions on Strengthening the Prevention and Control of Dioxin Pollution", and during the "Twelfth Five-Year Plan" period, dioxin has become a key control object. Therefore, it is imperative to promote the dioxin emission reduction technology in the sintering process.

After patent retrieval, some related technical solutions have been disclosed, such as: a device and method for removing sulfur dioxide and dioxins from sintering flue gas (CN201110173596.1), sintering pellet flue gas desulfurization and denitrification collaborative treatment system and process ( CN201410072049.8), a sintering flue gas desulfurization, dioxin and dust removal integrated equipment without electrostatic precipitator (CN201310713790.3), etc.; although the above-mentioned technical scheme can realize the synchronous emission reduction of SO ₂ and dioxin, the above-mentioned The technical solution belongs to the terminal treatment, which is the absorption emission reduction with large smoke volume and low content, and has not realized the online pollutant emission reduction in the sintering process, which makes the investment and operation cost of pollutant emission reduction huge, making iron and steel enterprises Reluctance to reduce pollutant emissions has greatly increased the burden of emission reduction on enterprises, and the products of emission reduction are prone to secondary pollution.

In addition, there have been related technical solutions related to online SO2 emission reduction in the sintering process _: online desulfurization method for sintering process (CN99111573.2), desulfurization method for iron ore sintering process based on adding inhibitors (CN201110022407. 0), an online desulfurization method in the sintering process (CN201410109130.9), etc.; the above technical solution realizes online desulfurization in the sintering process by adding ammonia substances in the sintering material layer. Regarding the on-line dioxin emission reduction in the sintering process, related technical solutions have also been disclosed: method for reducing dioxin emission in the iron ore sintering process (CN201110180658.1), a new energy-saving and emission-reducing sintering machine system and sintering method (CN201310167718.5), etc., the above-mentioned technical scheme realizes the emission reduction of dioxins in the sintering process by adding ammonia substances in the sintering material layer as dioxin formation inhibitors. The above-mentioned disclosed technical scheme proposes three adding schemes of ammonia inhibitors, (1) mixing all the ammonia inhibitors into the sintered material layer, (2) adding the ammonia inhibitors to a certain part of the sintered material layer (3) Spray the ammonia inhibitor on the sintering mixture layer.

Anhui University of Technology has been committed to the research of pollutant emission reduction in the sintering process. After years of scientific experimental research, it is found that the above three technical solutions have the following technical disadvantages:

(1) The amount of ammonia inhibitors added is extremely small relative to the quality of the sintering mixture. If the ammonia inhibitors are added to the sintering mixture, it will inevitably make the addition of ammonia inhibitors untargeted. On the one hand , if the amount of ammonia inhibitor added is small, the emission reduction effect will be greatly reduced, making the emission reduction incomplete. Exhaust cost, and easy to produce secondary pollution, and the amount of urea added will seriously affect the quality of sinter;

(2) The amount of ammonia inhibitor added is extremely small relative to the mass of the sintered mixture. If the ammonia inhibitor is added to a certain height, it is difficult to add urea particles to the The specified height makes the desulfurization effect of urea worse, and due to the complexity and changeability of the sintering process, the moisture content, fuel content, and raw material characteristics of the sintering mixture will have a greater impact on the sintering process, resulting in a greater impact on the sintering process. Fluctuation, if the ammonia inhibitor is added to a specific height of the sinter layer, it is easy to cause fluctuations in the emission reduction effect; in addition, due to the continuous generation of dioxins during the cooling process of the flue gas, if the inhibitor is only added At a certain height of the sintering mixture layer, after the flue gas passes through the height of sintering, the temperature of the flue gas is still in the temperature range where dioxins are generated, and it is difficult to reduce the emission of dioxins;

(3) During the sintering process, if urea is dissolved in water and added to the full mixture, the technical indicators of the sinter will deteriorate, and will decrease with the increase of the amount of urea added, which will have a greater impact on the quality of the sinter and directly affect The quality of the ore entering the furnace is seriously affected, which seriously affects the smooth operation of the blast furnace.

Although the above-mentioned technical solutions have realized the on-line emission reduction of pollutants in the sintering process, they are all specific emission reductions of a single pollutant, and cannot realize the synergistic emission reduction of SO ₂ and dioxins; and because SO ₂ and dioxins are The production mechanism, generation area, and emission reduction conditions of oxins are quite different, and in addition to the complexity of the sintering process, each layer of sintering is constantly changing during the sintering process, making it difficult for the existing technical solutions to achieve SO in the sintering process. ₂ and synergistic emission reduction of dioxins.

If you want to achieve the synergistic emission reduction of SO ₂ and dioxins in the sintering process, it is not possible to realize the synergistic emission reduction of SO ₂ and dioxins in the sintering process by simply superimposing the emission reduction methods. It is precisely because of the difficulty of synergistic emission reduction , making it difficult for the existing technology to overcome the technical bottleneck of online SO ₂ and dioxin synergistic emission reduction in the sintering process.

Prior to this, the applicant creatively proposed to set a synergistic emission reduction material layer in the sintering mixture layer through a long period of scientific research, and add ammonia inhibitors to the synergistic emission reduction material layer, so as to realize the sintering process. SO ₂ and dioxin synergistic emission reduction, and has applied for a patent: a sintering process SO ₂ , dioxin synergistic emission reduction method and system (Chinese patent application number: 201410592066.4); however, urea is added to sintering in the form of a solution The material layer, its technological process is relatively complicated, and the emission reduction efficiency needs to be further improved.

In addition, the existing on-line emission reduction scheme only proposes a method to reduce the emission of sintering flue gas pollutants. However, since the emission reduction products are extremely small, if a dust collector is used for dust removal, it will inevitably cause generation of sintering exhaust gas. The pressure loss causes the unbalanced air volume during the sintering process, which makes the sintering production unstable and seriously affects the sintering production. The existing technical solutions make it difficult to collect the products produced by the combination of ammonia inhibitors and pollutants, resulting in the failure to collect the products after emission reduction, and the inability to process the sintered products of online emission reduction, making emission reduction a The "half" project only discharges pollutants into the air in another way, without achieving substantial reduction of pollutants.

Contents of the invention

1. The technical problem to be solved by the invention

The purpose of the present invention is to overcome the disadvantages in the prior art that the sintering flue gas pollutant emission reduction technology belongs to the terminal treatment, and it is difficult to realize the synergistic emission reduction of SO ₂ and dioxins in the sintering process, and provides a method based on adding solids to suppress The synergistic emission reduction method of SO ₂ and dioxins in the sintering process of the agent realizes the synergistic emission reduction of SO ₂ and dioxins in the sintering process on the premise that the quality of the sinter is basically not affected.

2. Technical solution

In order to achieve the above object, the technical scheme provided by the invention is:

A method for synergistic emission reduction of SO ₂ and dioxins in the sintering process based on the addition of solid inhibitors according to the present invention, the specific steps are as follows:

Step 1: Sinter the cloth

(A) pave the bottom material layer on the upper part of the sintering trolley;

(B) laying the sintered mixture above the bottom layer to form the first mixture layer;

(C) Mix the solid ammonia inhibitor particles with the sintering mixture, the addition of the solid ammonia inhibitor particles is 0.04%-0.11% of the total mass of the sinter layer, and then the solid ammonia inhibitor particles will be mixed with The sintered mixture pavement forms a synergistic emission reduction layer above the first mixture layer;

(D) paving the sintered mixture above the synergistic emission reduction material layer to form the second mixture layer;

Step 2: Centralized collection and treatment of flue gas

After ignition, carry out draft sintering. During the draft sintering process of the sintering machine, the flue gas in the bellows at the middle and rear of the sintering trolley will flow into the bag filter through the booster pump. The booster pressure of the booster pump is 0.8 -1.0KPa, control the wind speed in the bag filter to 0.75-0.85m/mim, and the sintering flue gas after dust removal by the bag filter is introduced into the main flue of the sintering machine through the pipe.

Furthermore, the distance between the bottom of the synergistic emission reduction material layer and the sintering trolley is 1/10-1/8 of the total height of the sintering material layer, and the thickness of the synergistic emission reduction material layer is 1/8 of the total height of the sintering material layer 8-1/5.

Further, the solid ammonia inhibitor in the synergistic emission reduction material layer is urea particles; the mass percentage of carbon-containing fuel in the synergistic emission reduction material layer is 3.5%-5.0%, and the The mass percent content of CaO in the synergistic emission reduction material layer is 4.5%-6.0%.

Furthermore, the average particle diameter of the urea particles is 0.30-0.50mm.

Furthermore, the bellows at the middle and rear are the bellows corresponding to the position below 1/2-3/4 of the length direction of the sintering trolley.

3. Beneficial effect

Compared with the existing known technology, the technical solution provided by the invention has the following remarkable effects:

A method for synergistic emission reduction of SO ₂ and dioxins in the sintering process based on the addition of solid inhibitors in the present invention creatively proposes to pave the sinter mixture mixed with solid ammonia inhibitor particles above the first mixture layer to form Synergistic emission reduction material layer, and the average particle size of ammonia inhibitor particles is 0.30-0.50mm, and the content of carbon-containing fuel and CaO in the synergistic emission reduction material layer is creatively adjusted, forming a wider sintering material layer The synergistic emission reduction zone makes the sintering flue gas inhibit the formation of dioxins in the process of cooling until the temperature of the sintering flue gas drops below the synthesis temperature of dioxins, and while inhibiting the formation of dioxins, it accumulates in the overhumidity The SO ₂ in the layer reacts with urea, so that the synergistic emission reduction zone covers the dioxin generation layer and the effective position of desulfurization; thus a breakthrough has been realized in the online SO ₂ and dioxin synergistic emission reduction during the sintering process , and ensure the normal production of sintering operations, overcome the technical disadvantages of single pollutant terminal treatment in the prior art, greatly reduce the cost of pollutant emission reduction in the sintering process, and reduce the burden of emission reduction for iron and steel enterprises; and , ammonia inhibitors are added to the sintering mixture in the form of particles, which ensures that the technical indicators of the sintering process are basically not affected, and provides a high-efficiency, low-cost sintering process for iron and steel enterprises. collaborative emission reduction technology;

In addition, the invention creatively proposes to centralize the flue gas in the bellows at the middle and rear of the sintering trolley, and transfer the flue gas after bag dust removal into the main flue through a booster pump, ensuring the balance of the air volume during the sintering process , thus ensuring the smooth production of the sintering process.

Description of drawings

Fig. 1 is the overall structure schematic diagram of the distributing device of the synergistic emission reduction method of the present invention;

Fig. 2 is the cloth schematic diagram of synergistic emission reduction method of the present invention;

Fig. 3 is a trend chart of the desulfurization rate and dioxin emission reduction efficiency when the material layer thickness of the synergistic emission reduction of the present invention is different.

Explanation of the labels in the schematic diagram:

1. Bottom layer; 2. First mixture layer; 3. Synergistic emission reduction layer; 4. Second mixture layer; 5. Sintering trolley; 61. Bottom material distribution device; 62. First mixture distribution 63. Distributing device for emission reduction mixture; 64. Second distributing device for mixture; 7. Concentrated treatment flue; 8. Main flue; 9. Bag filter.

detailed description

In order to further understand the contents of the present invention, the present invention will be further described below in conjunction with the examples.

Example 1

Referring to Fig. 1, Fig. 2 and Fig. 3, a method for synergistic emission reduction of SO ₂ and dioxin in the sintering process based on the addition of solid inhibitors in this embodiment, the distributing device is set on the upper part of the sintering trolley 5, the The top of the sintering trolley 5 is successively provided with a bottom material distribution device 61, a first mixture distribution device 62, an emission reduction mixture distribution device 63, and a second mixture distribution device 64 (as shown in Figure 1), wherein: the described The base material distributing device 61 is used to pave the base material layer 1 on the upper part of the sintering trolley 5, and the first mixed material distributing device 62 is used to pave the sintered mixture above the base material layer 1 and form the first mixed material Layer 2, the total thickness of the bottom layer 1 and the first mixture layer 2 is 90mm; the emission reduction mixture distributing device 63 is used to pave and mix ammonia-based inhibitors above the first mixture layer 2. The sintering mixture of the agent, and form a synergistic emission reduction material layer 3, the height of the bottom of the synergistic emission reduction material layer 3 from the sintering trolley 5 is 90mm, and the thickness of the synergistic emission reduction material layer 3 is 100mm; the second mixing The material distributing device 64 is used to pave the sintered mixture above the synergistic emission reduction material layer 3, and form the second mixture layer 4, the described bottom layer 1, the first mixture layer 2, and the cooperative emission reduction material layer 3 and the total layer height (total thickness) of the second mixture layer 4 is 800mm. The area of the sintering trolley 5 in this embodiment is 180m ² , and there are 14 bellows under the sintering trolley 5, which are numbered from 1 ^# to 14 ^# from the head of the sintering machine.

The lower part of the sintering trolley 5 of this embodiment is provided with a bellows, wherein the bellows at the middle and rear of the sintering trolley 5 are connected to the centralized processing flue 7, and the bellows at the middle and rear are 1/2-3 of the length direction of the sintering trolley 5. The corresponding bellows below the /4 position are the 7 ^# to 11 ^# bellows below the sintering trolley 5 of this embodiment.

The concentrated treatment flue 7 of this embodiment is connected to the inlet end of the bag filter 9 through an additional pump. The total filter area of filter 9 is 2413m ² , and the material of the filter bag is PTFE composite filter material. In the process of using bag dust removal, the ammonium sulfate generated by emission reduction can be supplemented, and the emission reduction products can be used as resources. The concept of turning waste into treasure. The outlet end of the bag filter 9 is connected to the main flue 8, and the flue gas after the bag dust removal is brought into the main flue 8 through the booster pump, which ensures the balance of the air volume during the sintering process, thereby ensuring the sintering process. stable production; the remaining bellows of the sintering trolley 5 are directly connected to the main flue 8, that is, the bellows 1 ^# to 6 ^# and the bellows 12 ^# to 14 ^# of this embodiment are directly connected to the main flue 8.

The applicant of the present invention has passed a series of explorations for a long time in order to realize the synergistic emission reduction of _SO2 and dioxin in the sintering process _; however, due to the production mechanism, generation area, and The emission reduction conditions are very different, making it difficult for existing technical solutions to achieve the synergistic emission reduction of SO ₂ and dioxins in the sintering process; the main factors that limit the synergistic emission reduction of SO ₂ and dioxins in the sintering process are as follows point:

(1) The generation area is different: during the sintering process, the concentrated emission area of SO ₂ is in the combustion layer and the dry layer, while the concentration of SO ₂ is collected in the over-humidity layer; however, there are two main generation areas of dioxin during the sintering process, One is the cooling zone of the sinter layer, and the other is the dry preheating layer of the sintering layer, especially the dioxins generated in the dry preheating layer cannot be degraded;

( ₂ ) The temperature conditions for emission reduction are different: when urea is used to reduce SO2 emissions, the reaction temperature between urea and SO2 needs to be lower _than 100°C; however, the temperature range for inhibiting dioxin formation is 200-800°C;

(3) Different emission reduction mechanisms: when urea is used to reduce SO ₂ emissions, since SO ₂ concentrates in a relatively narrow layer of sintered material layer, it is only necessary to add urea to this narrow layer. Emission reduction can be achieved; however, when suppressing the formation of dioxins, it is necessary to continuously suppress the formation of dioxins when the flue gas temperature passes through the temperature range of 200-800°C.

It is precisely because of the above factors that seriously hinder the synergistic emission reduction of SO ₂ and dioxins during the sintering process, coupled with the complexity and volatility of the sintering process, the various layers of the sintering process are constantly changing during the sintering process, making the online The reduction of SO ₂ and dioxin emissions has become a major technical bottleneck.

After a long period of unremitting exploration, the applicant of the present invention finally proposed to pave the sintered mixture mixed with ammonia inhibitors on the first mixed material layer 2 to form a synergistic emission reduction material layer 3, so that the sintered material layer A wider synergistic emission reduction zone is formed in the sintering flue gas to suppress the formation of dioxins during the cooling process until the temperature of the sintering flue gas drops below the synthesis temperature of dioxins, and while suppressing the formation of dioxins , the SO gathered in the super _- wet layer reacts with urea, so that the synergistic emission reduction zone covers the effective position of the dioxin generation layer and desulfurization; and, the present invention improves the content of CaO in the synergistic emission reduction material layer 3, To provide a weakly alkaline environment for urea to achieve dioxin emission reduction, the applicant was surprised to find that the emission reduction effect is greatly improved; in addition, the present invention increases the content of carbon-containing fuel in the synergistic emission reduction material layer 3, thereby ensuring the sintering Various technical indicators provide guarantee for the normal sintering production. On the premise of ensuring the sintering quality, the formation of dioxins in the sintering process is suppressed, and the emission reduction of dioxins in the sintering process is realized; and the SO ₂ accumulated in the over-humidity layer It reacts with urea, thereby achieving a breakthrough in the synergistic emission reduction of online SO ₂ and dioxins during the sintering process, overcoming this major technical bottleneck.

A method for synergistic emission reduction of SO ₂ and dioxins in the sintering process of the present invention, the specific implementation steps are as follows:

Step 1: Sinter the cloth

(A) Utilize the bottom material distributing device 61 to pave the bottom material on the upper part of the sintering trolley 5 to form the bottom material layer 1;

(B) Utilize the first mixture distributing device 62 to lay the sintered mixture above the bottom layer 1 to form the first mixture layer 2, the total thickness of the bottom layer 1 and the first mixture layer 2 is 90mm;

(C) Mix the solid ammonia inhibitor particles with the sintering mixture, wherein the solid ammonia inhibitor is urea particles, and the average particle diameter of the urea particles is 0.30-0.50mm, and the added quality of urea is the sintering material layer 0.09% of the total mass, utilize the emission reduction mixture distributing device 63 to pave the sintered mixture mixed with urea particles above the first mixture layer 2 to form a synergistic emission reduction layer 3, and the bottom distance of the synergy emission reduction layer 3 The height of the sintering trolley 5 is 90mm, and the thickness of the collaborative discharge reduction material layer 3 is 100mm;

(D) Utilize the second mixed material distributing device 64 to pave the sintered mixed material above the cooperative emission reduction material layer 3 to form the second mixed material layer 4;

Step 2: Centralized collection and treatment of flue gas

Ventilation sintering is carried out after ignition. During the process of ventilation sintering of the sintering machine, the flue gas in the bellows at the middle and rear of the sintering trolley 5 is brought into the centralized processing flue 7, and the flue gas in the centralized processing flue 7 passes through the booster pump. Into the bag filter 9, the boost pressure of the booster pump is 0.9KPa, the wind speed in the bag filter 9 is controlled to be 0.80m/min, and the sintering flue gas after the bag filter 9 is dedusted is introduced into the sintering pipe. Machine main flue 8.

The ammonia inhibitor solution in the synergistic emission reduction material layer 3 of this embodiment is a urea solution, wherein the amount of urea added is 0.09% of the total mass of the sintered material layer, and the total mass of the sintered material layer is the bottom layer 1 , the sum of the layer quality of the first mixed material layer 2 , the cooperative emission reduction material layer 3 and the second mixed material layer 4 . The mass percentage of the carbonaceous fuel in the sintered mixture of the first mixture layer 2 and the second mixture layer 4 of this embodiment is 3.2%, and the carbonaceous fuel is coke powder, and the first mixture layer 2 and the mass percentage of CaO in the sintered mixture of the second mixture layer 4 is 4.2%; the mass percentage of the carbon-containing fuel in the synergistic emission reduction material layer 3 is 4.0%. It is coke powder, and the mass percentage of CaO in the synergistic emission reduction material layer 3 is 5.0%.

After the sintering is stable, measure the SO2 concentration and dioxin concentration of the flue gas during the sintering process in the main flue ₈ , and calculate the desulfurization rate and dioxin emission reduction efficiency, and record them as in Table 1, the technology for detecting sinter The indicators are recorded in Table 2.

Desulfurization rate = (SO ₂ concentration in the flue gas of the benchmark experiment - SO ₂ concentration in the flue gas after emission reduction)/SO ₂ concentration in the flue gas of the benchmark experiment × 100%.

Dioxin emission reduction efficiency = (dioxin concentration in the flue gas of the benchmark experiment - dioxin concentration in the flue gas after emission reduction) / dioxin concentration in the flue gas of the benchmark experiment × 100%.

Comparative example 1

This comparative example is used as a benchmark experiment. The sintering process of this comparative example is the same as that of Example 1. The difference is that the thickness of the collaborative emission reduction material layer 3 is zero, that is, the synergistic emission reduction material layer 3 is not provided, and only the bottom material layer is provided. 1. The first mixed material layer 2 and the second mixed material layer 4, and the total height of the material layer (the total thickness of the material layer) of the bottom layer 1, the first mixed material layer 2 and the second mixed material layer 4 is 800mm. After the sintering is stable, measure the concentration of SO ₂ and dioxin in the flue gas during the sintering process, and record them as shown in Table 1, and record the technical indicators of the sintered ore as shown in Table 2, as the benchmark for later experiments.

Comparative example 2

The sintering process of this comparative example is the same as that of Example 1, and the addition of urea in this comparative example, the thickness of the synergistic emission reduction material layer 3 is the same as that of Example 1, and the bottom material layer 1, the first mixed material layer 2, the synergistic emission reduction material layer The total layer height (total thickness) of the discharge layer 3 and the second mixture layer 4 is 800mm, the difference is that: the ammonia inhibitor is first mixed with water, fully dissolved and then mixed with the sintered mixture Mixing is carried out, and then the sintered mixture mixed with the liquid ammonia inhibitor is paved on the first mixture layer 2 to form a synergistic emission reduction layer 3 . After the sintering is stable, measure the concentration of SO ₂ and dioxin in the flue gas during the sintering process, and record them as shown in Table 1, and record the technical indicators of the sintered ore as shown in Table 2.

Table 1 SO ₂ , dioxin concentration and emission reduction efficiency in flue gas of sintering experiment

Table 2 Sinter technical indicators

Through the analysis of the data in Table 1 and Table 2, the following conclusions can be drawn:

(1) Compared with the benchmark experiment in Comparative Example 1, when a synergistic emission reduction material layer 3 is provided between the first mixture layer 2 and the second mixture layer 4, no matter what form the ammonia inhibitor is added In the collaborative emission reduction material layer 3, the desulfurization rate is above 84%, and the emission reduction efficiency of dioxin is above 62%, which has a significant synergistic emission reduction effect;

(2) When comparative example 2 was compared with Example 1, it was found that when ammonia inhibitors were added to the synergistic emission reduction material layer in the form of solid particles (i.e. Example 1), the desulfurization rate: 85.03%, dioxin Dioxin emission reduction efficiency is: 64.35%, which has a better emission reduction effect than the 84.44% desulfurization rate and 62.39% dioxin emission reduction efficiency of Comparative Example 1;

(3) Adopting the technical solution of Example 1, the applicant was surprised to find that not only the efficiency of synergistic emission reduction of SO ₂ and dioxins has been further improved, but also the technical indicators of the sintered ore are basically unchanged, and the quality of the sintered ore is almost No effect, that is, when the ammonia inhibitor is added to the collaborative emission reduction material layer 3 in the form of solid particles, the synergistic emission reduction of SO ₂ and dioxin can be realized on the premise that the quality of the sinter is basically unchanged.

Through the above analysis, it was found that the SO ₂ concentration (mg/Nm ³ ) in the flue gas in Example 1 was reduced from 694.2 mg/Nm ³ to 103.9 mg/Nm ³ , the emission reduction efficiency reached 85.03%, and the dioxin in the flue gas The concentration (pg-TEQ/Nm ³ ) was reduced from 763pg-TEQ/Nm ³ to 272pg-TEQ/Nm ³ , and the emission reduction efficiency reached 64.35%, reaching the national pollutant emission reduction standard. Moreover, through the analysis of various technical indicators of the sintered ore, it was found that compared with Comparative Example 1, the various technical indicators of the sintered ore in Example 1 were basically not affected, thus achieving the goal of ensuring that the various technical indicators of the sintered ore were basically not affected. Under the premise of changes, the synergistic emission reduction of online SO ₂ and dioxins during the sintering process has overcome the major technical problems that are difficult to achieve synergistic emission reduction. The desulfurization rate and dioxin emission reduction efficiency in Examples 1-7 are shown in FIG. 3 .

The present invention creatively proposes to set a wider synergistic emission reduction material layer 3 in the sintering mixture layer, and the synergistic emission reduction material layer 3 is added with urea as a dioxin formation inhibitor, and urea is added to the sintering mixture layer in the form of solid particles In the synergistic emission reduction material layer 3, the average particle size of urea is 0.30-0.50mm. In addition, the present invention adjusts the composition ratio in the synergistic emission reduction material layer 3, so that the sintering flue gas suppresses the generation of dioxins during the cooling process until the temperature of the sintering flue gas drops below the synthesis temperature of dioxins. While inhibiting the formation of dioxins, the SO2 accumulated in the super _- wet layer reacts with urea, so that the synergistic emission reduction zone covers the dioxin generation layer and the effective position of desulfurization; moreover, the present invention creatively improves the synergistic emission reduction The content of CaO in the discharge layer 3 provides a slightly alkaline environment for the urea to realize the synergistic emission reduction of SO ₂ and dioxin, which greatly improves the emission reduction effect.

In addition, the content of carbon-containing fuel in the synergistic emission reduction material layer 3 is appropriately increased, and the technical solution is creatively changed, adding urea in the form of solid particles to the synergistic emission reduction material layer 3, so that the various technologies of sintering The indicators are basically not affected, so as to ensure the various technical indicators of sintering and provide guarantee for the normal operation of sintering production; moreover, while realizing the reduction of dioxin emissions in the sintering process, the SO ₂ accumulated in the over-humidity layer reacts with urea , so that the emission of SO ₂ in the sintering flue gas is reduced, thereby realizing the synergistic emission reduction of SO ₂ and dioxins in the sintering process, which is of great significance to the clean production and sustainable development of the iron and steel industry.

Example 2

The basic process of the SO ₂ and dioxin synergistic emission reduction method in the sintering process of this embodiment is the same as that of Embodiment 1, the difference is: the bottom layer 1, the first mixed material layer 2, and the synergistic emission reduction material in this embodiment The total height (total thickness) of the layer 3 and the second mixture layer 4 is 800mm, and the thickness of the collaborative emission reduction layer 3 is 110mm, and the concentration of SO ₂ and dioxin is detected, and the desulfurization is calculated efficiency, the emission reduction efficiency of dioxins, the desulfurization rate of this embodiment is 86.43%, and the emission reduction efficiency of dioxins is 65.84%.

Example 3

The basic process of the SO ₂ and dioxin synergistic emission reduction method in the sintering process of this embodiment is the same as that of Embodiment 1, the difference is: the bottom layer 1, the first mixed material layer 2, and the synergistic emission reduction material in this embodiment The total height (total thickness) of layer 3 and the second mixture layer 4 is 800mm, and the thickness of layer 3 for synergistic emission reduction is 120mm, and the concentration of SO ₂ and dioxin is detected, and the desulfurization is calculated Emission reduction efficiency, dioxin, the desulfurization rate of this embodiment is 87.29%, the emission reduction efficiency of dioxin is 66.71%.

Example 4

The basic process of the SO ₂ and dioxin synergistic emission reduction method in the sintering process of this embodiment is the same as that of Embodiment 1, the difference is: the bottom layer 1, the first mixed material layer 2, and the synergistic emission reduction material in this embodiment The total height (total thickness) of layer 3 and the second mixture layer 4 is 800mm, and the thickness of layer 3 for synergistic emission reduction is 130mm, and the concentration of SO ₂ and dioxin is detected, and the desulfurization is calculated Emission reduction efficiency, dioxin, the desulfurization rate of this embodiment is 88.23%, the emission reduction efficiency of dioxin is 68.19%.

Example 5

The basic process of the SO ₂ and dioxin synergistic emission reduction method in the sintering process of this embodiment is the same as that of Embodiment 1, the difference is: the bottom layer 1, the first mixed material layer 2, and the synergistic emission reduction material in this embodiment The total height (total thickness) of layer 3 and the second mixed material layer 4 is 800mm, and the thickness of material layer 3 for synergistic emission reduction is 140mm, and the concentration of SO ₂ and dioxin is detected, and the desulfurization is calculated efficiency, the emission reduction efficiency of dioxins, the desulfurization rate of this embodiment is 87.71%, and the emission reduction efficiency of dioxins is 70.23%.

Example 6

The basic process of the SO ₂ and dioxin synergistic emission reduction method in the sintering process of this embodiment is the same as that of Embodiment 1, the difference is: the bottom layer 1, the first mixed material layer 2, and the synergistic emission reduction material in this embodiment The total height (total thickness) of layer 3 and the second mixture layer 4 is 800mm, and the thickness of layer 3 for synergistic emission reduction is 150mm, and the concentration of SO ₂ and dioxin is detected, and the desulfurization is calculated efficiency, the emission reduction efficiency of dioxins, the desulfurization rate of this embodiment is 85.45%, and the emission reduction efficiency of dioxins is 69.88%.

Example 7

The basic process of the SO ₂ and dioxin synergistic emission reduction method in the sintering process of this embodiment is the same as that of Embodiment 1, the difference is: the bottom layer 1, the first mixed material layer 2, and the synergistic emission reduction material in this embodiment The total height (total thickness) of layer 3 and the second mixed material layer 4 is 800mm, and the thickness of material layer 3 for synergistic emission reduction is 160mm, and the concentration of SO ₂ and dioxin is detected, and the desulfurization is calculated efficiency, the emission reduction efficiency of dioxins, the desulfurization rate of this embodiment is 84.28%, and the emission reduction efficiency of dioxins is 69.21%.

Example 8

The basic process of the SO ₂ and dioxin synergistic emission reduction method in the sintering process of this embodiment is the same as that of Embodiment 1, the difference is: the bottom layer 1, the first mixed material layer 2, and the synergistic emission reduction material in this embodiment The total height of the material layer (the total thickness of the material layer) of the layer 3 and the second mixed material layer 4 is 800mm, wherein in the collaborative emission reduction material layer 3, in addition to adding urea as a dioxin emission reduction inhibitor, and the applicant is in the collaborative emission reduction Material layer 3 is mixed with kaolin, wherein the amount of kaolin added is 0.01% of the total mass of the sintered material layer, and the pass rate of the kaolin added to the 200 mesh sieve is 75%, and the concentration of SO ₂ and dioxin is detected, and the calculated Desulfurization rate, dioxin emission reduction efficiency. Then, the applicant was surprised to find that the emission reduction efficiency of dioxin was improved when the conditions such as the thickness of the collaborative emission reduction material layer 3 and the urea ratio were the same, and the desulfurization rate of this embodiment was 84.98%, and the emission reduction efficiency of dioxin was 65.47%.

Example 9

The basic process of the SO ₂ and dioxin synergistic emission reduction method in the sintering process of this embodiment is the same as that of Embodiment 1, the difference is: the bottom layer 1, the first mixed material layer 2, and the synergistic emission reduction material in this embodiment The total height (total thickness) of the layer 3 and the second mixed material layer 4 is 800mm, wherein the bottom of the synergistic emission reduction layer 3 is 80mm from the bottom of the sintering trolley 5, and the amount of urea added is 80mm for the sintering layer. 0.04% of the total mass, the mass percentage of the carbon-containing fuel in the synergistic emission reduction material layer 3 is 3.5%, wherein the carbon-containing fuel is coal powder, and the quality of the CaO in the synergistic emission reduction material layer 3 The percentage content is 4.5%. In addition, the boost pressure of the booster pump is 0.8KPa, and the wind speed in the bag filter 9 is controlled to be 0.75m/mim. The concentration of SO ₂ and dioxin was detected, and the desulfurization rate and dioxin emission reduction efficiency were calculated. The desulfurization rate of this embodiment was 76.77%, and the dioxin emission reduction efficiency was 62.23%.

Example 10

The basic process of the SO ₂ and dioxin synergistic emission reduction method in the sintering process of this embodiment is the same as that of Embodiment 1, the difference is: the bottom layer 1, the first mixed material layer 2, and the synergistic emission reduction material in this embodiment The total height of the material layer (the total thickness of the material layer) of the layer 3 and the second mixed material layer 4 is 800mm, wherein the height from the bottom of the discharge reduction material layer 3 to the sintering trolley 5 is 100mm, wherein the addition of urea is sintered material layer 0.011% of the total mass, the mass percentage of the carbon-containing fuel in the synergistic emission reduction material layer 3 is 5.0%, wherein the carbon-containing fuel is composed of coke powder and coal powder in a mass ratio of 1:1, the synergistic The mass percentage of CaO in the emission reduction material layer 3 is 6.0%; in addition, the boost pressure of the booster pump is 1.0KPa, and the wind speed in the bag filter 9 is controlled to be 0.85m/mim. The concentration of SO ₂ and dioxin was detected, and the desulfurization rate and dioxin emission reduction efficiency were calculated. The desulfurization rate of this embodiment was 86.87%, and the dioxin emission reduction efficiency was 65.43%.

Claims (5)

1. A method for synergistic emission reduction of SO ₂ and dioxins in the sintering process based on the addition of solid inhibitors, characterized in that: the specific steps are as follows: Step 1: Sinter the cloth (A) pave the bottom material layer (1) on the top of the sintering trolley (5); (B) laying the sintered mixture on the top of the bottom layer (1) to form the first mixture layer (2); (C) Mix the solid ammonia inhibitor particles with the sintering mixture, the addition of the solid ammonia inhibitor particles is 0.04%-0.11% of the total mass of the sinter layer, and then the solid ammonia inhibitor particles will be mixed with The sintered mixture pavement forms a synergistic emission reduction layer (3) above the first mixture layer (2); (D) paving the sintered mixture above the synergistic emission reduction material layer (3) to form the second mixture layer (4); Step 2: Centralized collection and treatment of flue gas After ignition, carry out draft sintering. During the draft sintering process of the sintering machine, the flue gas in the bellows at the rear of the sintering trolley (5) is imported into the bag filter (9) through the booster pump. The booster pump The supercharging pressure is 0.8-1.0KPa, the wind speed in the bag filter (9) is controlled to be 0.75-0.85m/mim, and the sintering flue gas after dust removal by the bag filter (9) is introduced into the main flue of the sintering machine ( 8). 2. A method for synergistic emission reduction of SO ₂ and dioxins in the sintering process based on adding solid inhibitors according to claim 1, characterized in that the distance between the bottom of the synergistic emission reduction material layer (3) and the sintering trolley The distance between (5) is 1/10-1/8 of the total height of the sintered material layer, and the thickness of the cooperative emission reduction material layer (3) is 1/8-1/5 of the total height of the sintered material layer. 3. A method for synergistic emission reduction of SO ₂ and dioxins in the sintering process based on adding solid inhibitors according to claim 1, characterized in that: the solid ammonia in the synergistic emission reduction material layer (3) The inhibitor is urea particles; the mass percentage of carbon-containing fuel in the synergistic emission reduction material layer (3) is 3.5%-5.0%, and the mass percentage of CaO in the synergistic emission reduction material layer (3) The percentage is 4.5%-6.0%. 4 . The method for synergistic emission reduction of SO ₂ and dioxins in the sintering process based on adding solid inhibitors according to claim 3 , characterized in that: the average particle diameter of the urea particles is 0.30-0.50 mm. 5. A method for synergistic emission reduction of SO ₂ and dioxins in the sintering process based on the addition of solid inhibitors according to claim 4, characterized in that: the bellows at the middle and rear are the length of the sintering trolley (5) The bellows corresponding to the position below the direction 1/2-3/4.