CN104232241B - A kind of additive for fire coal and preparation method thereof - Google Patents

Abstract

The invention relates to a coal combustion additive and a preparation method thereof. The technical scheme is: the raw materials and contents of the coal-fired additive are: 40-55wt% catalyst, 25-35wt% oxidant, 10-20wt% sodium chloride, 2-6wt% sodium metasilicate pentahydrate, Sodium lignosulfonate is 0.05~0.15wt%. According to the raw materials and their contents: first, dissolving sodium lignosulfonate in water according to the solid-to-liquid mass ratio of 1: (2~4) to obtain a grinding aid solution; then uniformly Spray on the surface of the catalyst and grind in a ball mill until the particle size is less than 100 μm to obtain a ground fine powder; then mix the ground fine powder with an oxidant, sodium chloride, sodium metasilicate pentahydrate and 2 to 4 times the mass of the raw material mixed with water and stirred at a high speed on a shear mixer to obtain a coal-fired additive. The invention has the characteristics of low cost, resource saving and environmental friendliness, and the prepared coal-fired additive is easy to use, good in combustion effect and easy to popularize, and is suitable for cement industrial furnaces.

Description

A kind of coal combustion additive and preparation method thereof

technical field

The invention belongs to the technical field of coal combustion. It specifically relates to a coal combustion additive and a preparation method thereof.

Background technique

At present, researching and applying various clean coal technologies suitable for my country's national conditions, improving coal utilization efficiency, and reducing the emission of harmful gases and smoke such as sulfur dioxide and nitrogen oxides will become an effective strategy for the country to achieve sustainable energy development strategies and solve atmospheric environmental pollution. One of the measures. Although my country has a wide variety of coal mines and rich resources, the range of coal types that can adapt to the new dry process cement industry is relatively narrow. Large and medium-sized enterprises in my country's cement industry use more high-quality bituminous coal to increase the calorific value of coal powder and prevent kiln tail systems. Bonding and kiln ring formation. However, in terms of comprehensive utilization of resources and economic benefits, the cement industry bears the unshirkable responsibility for the utilization of low-volatile coal and high-ash coal.

In recent years, international cement kilns mostly use low-activity coal, and my country's cement kilns will also develop in terms of using low-quality coal, rationally utilizing resources, and reducing production costs. However, coal with low volatile content and high ash content is used in the decomposition kiln outside the kiln, because of its poor flammability, slow burning speed, high ignition temperature, and insufficient combustion. These defects will bring unstable factors to cement production. In addition, the cement industry is a large coal-fired consumer, and its NOx emissions are second only to my country's thermal power and automobile exhaust, ranking the third largest emitter, and the environmental protection situation is becoming increasingly severe.

In order to make up for the above defects, many technicians have developed different additives, but because these additives are expensive or ineffective, or cannot adapt to the production characteristics of the cement industry, it is difficult to be popularized and applied.

Contents of the invention

The present invention aims to overcome the defects of the prior art, and aims to provide a low-cost, resource-saving and environment-friendly preparation method for coal-fired additives. The coal-fired additives prepared by the method are easy to use, have good combustion effects and are easy to popularize and apply.

In order to achieve the above object, the technical solution adopted in the present invention is: the raw materials of coal-fired additives and their contents are: 40~55wt% catalyst, 25~35wt% oxidant, 10~20wt% sodium chloride, silicon metasilicate pentahydrate Sodium acid is 2~6wt%, and sodium lignosulfonate is 0.05~0.15wt%.

According to the raw materials and contents of the coal-fired additives: earlier, sodium lignosulfonate is dissolved in water according to the solid-to-liquid mass ratio of 1: (2 ~ 4) to obtain a grinding aid solution; the prepared grinding aid The solution is evenly sprayed on the surface of the catalyst, and then the catalyst sprayed with the grinding aid solution is ground in a ball mill until the particle size is less than 100 μm to obtain a ground fine powder; then the ground fine powder is mixed with an oxidizing agent, sodium chloride, five Sodium metasilicate water is mixed with water 2 to 4 times the mass of the raw material, and stirred at a high speed on a shear mixer to obtain a coal-fired additive.

Among the catalysts: steel slag is 25-35wt%; steelmaking desulfurization slag is 10-20wt%; cold-rolled iron oxide slag is 20-30wt%; chromium slag is 5-15wt%; manganese tailings is 5-15wt%; Manganese dioxide is 5~10wt%.

Among the oxidizing agents: potassium permanganate is 45-55wt%; potassium perchlorate is 45-55wt%.

Owing to adopting above-mentioned technical scheme, the present invention has following positive effect compared with prior art:

The invention uses industrial waste residue as a catalyst, turns waste into treasure, greatly reduces raw material cost, saves resources, and is environmentally friendly. The steel slag, steelmaking desulfurization slag, cold-rolled iron oxide slag, chromium slag and manganese tailings in the present invention contain a large amount of alkali metal and transition metal oxides, and the addition of these oxides forms ionization with opposite polarity between the two phases Potential difference, thereby weakening the original electromotive force, reducing the activation energy required for combustion, lowering the ignition temperature of the reaction, and making combustion easier, thereby accelerating the coal combustion rate, promoting the complete combustion of coal powder, and improving combustion efficiency. At the same time, metal oxides can change the physical form of the surface of coal powder or coke, thereby enhancing the adsorption of NO _X by coal powder or coke, and promoting the heterogeneous reduction reaction of coke; after the coal powder or coke is loaded with metal oxides, it can reduce the heterogeneity of coke. The activation energy of the phase reduction reaction increases the rate of the heterogeneous reaction, thereby playing a role in catalytic denitrification. Therefore, after adding the catalyst, the ignition temperature is reduced by 7.2~16.5℃, the burnout degree is increased by 2.3~6.5%, and the nitrogen oxide emission is reduced by 6.8~22.8%.

Potassium permanganate and potassium perchlorate in the present invention can gradually decompose and separate active oxygen in different temperature sections, which not only increases the contact area between fixed carbon and oxygen, promotes the complete combustion of fixed carbon, but also has a good effect on the combustion of flue gas. The combustible gas and suspended carbon particles in the gas play a great role, thereby reducing the consumption of coal and the blackness of the flue gas; the manganese dioxide generated after the combustion of potassium permanganate is a catalyst for the oxidation reaction, and can promote The oxidation reaction proceeds. Potassium chloride produced by the final decomposition of potassium perchlorate can also play a role in catalytic combustion.

The sodium chloride in the present invention can expand instantaneously at high temperature, so that the coal is in a fluffy state, the specific surface area is increased, the oxygen supply surface is enlarged, and the combustion is more complete. At the same time, when the temperature reaches 800°C, sodium chloride can be decomposed into elemental sodium and chlorine, both of which have catalytic and combustion-supporting effects.

What sodium metasilicate pentahydrate plays among the present invention is dispersing effect. After adding sodium metasilicate pentahydrate, other additives in the additive can be better dispersed in water, mixed more uniformly, and the utilization efficiency of the additive is improved.

The sodium lignosulfonate in the present invention is a typical lignosulfonate and has good grinding aiding effect. Sodium lignosulfonate is adsorbed on the particle surface, and the strength and hardness of the particle surface are changed. When completely adsorbed, the wear resistance of the particles is the least, and the surface hardness is also the least, which makes grinding easier and greatly improves the fineness. At the same time, the grinding aid can also prevent the particles from adhering to the medium or the mill to reduce the crushing force, thereby accelerating the grinding of the material. Aiming at the problem that the industrial waste residue is difficult to grind, after adding sodium lignosulfonate, the grinding fineness is improved, and the effect of the additive is further improved.

The additive prepared by the invention is a liquid additive, which is easy to spray evenly when mixed with coal and easy to use. The addition amount of the additive is small, and the effect is good; the adaptability of the coal type is good, and it is easy to popularize and apply.

Therefore, the invention has the characteristics of low cost, resource saving and environmental friendliness, and the prepared coal-fired additive is easy to use, has good combustion effect and is easy to popularize and apply, and is suitable for kilns in the cement industry.

detailed description

In order to better understand the present invention, the present invention will be described in detail below in combination with specific embodiments.

In order to avoid repetition, the catalyst and oxidizing agent involved in this specific embodiment are first described in a unified manner as follows, and will not be repeated in the examples:

Among the catalysts: steel slag is 25-35wt%; steelmaking desulfurization slag is 10-20wt%; cold-rolled iron oxide slag is 20-30wt%; chromium slag is 5-15wt%; manganese tailings is 5-15wt%; Manganese dioxide is 5~10wt%.

Among the oxidizing agents: potassium permanganate is 45-55wt%; potassium perchlorate is 45-55wt%.

Example 1

A coal combustion additive and a preparation method thereof. The raw materials and contents of coal-fired additives are: 50~55wt% catalyst, 27~32wt% oxidant, 10~15wt% sodium chloride, 2~6wt% sodium metasilicate pentahydrate, sodium lignosulfonate 0.05~0.15wt%.

According to the raw materials and contents of the coal-fired additives: earlier, sodium lignosulfonate is dissolved in water according to the solid-to-liquid mass ratio of 1: (2 ~ 4) to obtain a grinding aid solution; the prepared grinding aid The solution is evenly sprayed on the surface of the catalyst, and then the catalyst sprayed with the grinding aid solution is ground in a ball mill until the particle size is less than 100 μm to obtain a ground fine powder; then the ground fine powder is mixed with an oxidizing agent, sodium chloride, five Sodium metasilicate water is mixed with water 2 to 4 times the mass of the raw material, and stirred at a high speed on a shear mixer to obtain a coal-fired additive.

The coal-fired additive prepared in this example was added to a medium-ash ultra-high-order bituminous coal at an amount of 0.2% of the coal-fired mass, and mixed in a drum for 30 minutes (20r/min). The experimental results on the settling furnace and thermal gravimetry show that: the ignition temperature of the coal sample is reduced by 9.3~16.5℃; the burnout degree is increased by 3.3~6.5%; the nitrogen oxide emission is reduced by 6.8~15.3%.

Example 2

A coal combustion additive and a preparation method thereof. The raw materials and contents of coal-fired additives are: catalyst 46~52wt%, oxidant 25~30wt%, sodium chloride 15~20wt%, sodium metasilicate pentahydrate 2~6wt%, sodium lignosulfonate 0.05~0.15wt%.

According to the raw materials and contents of the coal-fired additives: earlier, sodium lignosulfonate is dissolved in water according to the solid-to-liquid mass ratio of 1: (2 ~ 4) to obtain a grinding aid solution; the prepared grinding aid The solution is evenly sprayed on the surface of the catalyst, and then the catalyst sprayed with the grinding aid solution is ground in a ball mill until the particle size is less than 100 μm to obtain a ground fine powder; then the ground fine powder is mixed with an oxidizing agent, sodium chloride, five Sodium metasilicate water is mixed with water 2 to 4 times the mass of the raw material, and stirred at a high speed on a shear mixer to obtain a coal-fired additive.

The coal-fired additive prepared in this example was added to a certain high-ash high-rank bituminous coal in an amount of 0.2% of the coal-fired mass, and mixed in a drum for 30 minutes (20r/min). The experimental results on the settling furnace and thermal gravimetry show that: the ignition temperature of the coal sample is reduced by 9.1~14.8℃; the burnout degree is increased by 3.1~5.7%; the nitrogen oxide emission is reduced by 12.5~18.6%.

Example 3

A coal combustion additive and a preparation method thereof. The raw materials and contents of coal-fired additives are: 40~46wt% catalyst, 32~35wt% oxidant, 16~20wt% sodium chloride, 2~6wt% sodium metasilicate pentahydrate, sodium lignosulfonate 0.05~0.15wt%.

According to the raw materials and contents of the coal-fired additives: earlier, sodium lignosulfonate is dissolved in water according to the solid-to-liquid mass ratio of 1: (2 ~ 4) to obtain a grinding aid solution; the prepared grinding aid The solution is evenly sprayed on the surface of the catalyst, and then the catalyst sprayed with the grinding aid solution is ground in a ball mill until the particle size is less than 100 μm to obtain a ground fine powder; then the ground fine powder is mixed with an oxidizing agent, sodium chloride, five Sodium metasilicate water is mixed with water 2 to 4 times the mass of the raw material, and stirred at a high speed on a shear mixer to obtain a coal-fired additive.

The coal-burning additive prepared in this example was added to a medium-rank bituminous coal with a relatively high ash content in an amount of 0.2% of the coal-fired mass, and mixed in a drum for 30 minutes (20r/min). The experimental results on the settling furnace and thermal gravimetry show that: the ignition temperature of the coal sample is reduced by 7.2~9.3℃; the burnout degree is increased by 2.3~4.2%; the nitrogen oxide emission is reduced by 15.9~22.8%.

Compared with the prior art, this specific embodiment has the following positive effects:

This embodiment uses industrial waste residue as a catalyst to turn waste into treasure, greatly reduces the cost of raw materials, saves resources, and is environmentally friendly. The steel slag, steelmaking desulfurization slag, cold-rolled iron oxide slag, chromium slag and manganese tailings in this specific embodiment contain a large amount of alkali metal and transition metal oxides. The addition of these oxides forms a phase with opposite polarity. The ionization potential difference weakens the original electromotive force, reduces the activation energy required for combustion, lowers the ignition temperature of the reaction, and makes combustion easier, thereby accelerating the coal combustion rate, promoting the complete combustion of coal powder, and improving the combustion efficiency. efficiency. At the same time, metal oxides can change the physical form of the surface of coal powder or coke, thereby enhancing the adsorption of NO _X by coal powder or coke, and promoting the heterogeneous reduction reaction of coke; after the coal powder or coke is loaded with metal oxides, it can reduce the heterogeneity of coke. The activation energy of the phase reduction reaction increases the rate of the heterogeneous reaction, thereby playing a role in catalytic denitrification. Therefore, after adding the catalyst, the ignition temperature is reduced by 7.2~16.5℃, the burnout degree is increased by 2.3~6.5%, and the nitrogen oxide emission is reduced by 6.8~22.8%.

Potassium permanganate and potassium perchlorate in this specific embodiment can gradually decompose and separate active oxygen in different temperature sections, which not only increases the contact area between fixed carbon and oxygen, promotes the complete combustion of fixed carbon, but also prevents burnout. The combustible gas and suspended carbon particles in the flue gas play a big role, thereby reducing the consumption of coal and the blackness of the flue gas; the manganese dioxide generated after the combustion of potassium permanganate is a catalyst for the oxidation reaction, and Can promote the oxidation reaction. Potassium chloride produced by the final decomposition of potassium perchlorate can also play a role in catalytic combustion.

The sodium chloride in this specific embodiment can expand instantaneously at high temperature, so that the coal is in a fluffy state, the specific surface area is increased, the oxygen supply surface is enlarged, and the combustion is more complete. At the same time, when the temperature reaches 800°C, sodium chloride can be decomposed into elemental sodium and chlorine, both of which have catalytic and combustion-supporting effects.

What sodium metasilicate pentahydrate plays in this specific embodiment is dispersion effect. After adding sodium metasilicate pentahydrate, other additives in the additive can be better dispersed in water, mixed more uniformly, and the utilization efficiency of the additive is improved.

The sodium lignosulfonate in this specific embodiment is a typical lignosulfonate, which has a good grinding aid effect. Sodium lignosulfonate is adsorbed on the particle surface, and the strength and hardness of the particle surface are changed. When completely adsorbed, the wear resistance of the particles is the least, and the surface hardness is also the least, which makes grinding easier and greatly improves the fineness. At the same time, the grinding aid can also prevent the particles from adhering to the medium or the mill to reduce the crushing force, thereby accelerating the grinding of the material. Aiming at the problem that the industrial waste residue is difficult to grind, after adding sodium lignosulfonate, the grinding fineness is improved, and the effect of the additive is further improved.

The additive prepared in this specific embodiment is a liquid additive, which is convenient to spray evenly and easy to use when mixed with coal. The addition amount of the additive is small, and the effect is good; the adaptability of the coal type is good, and it is easy to popularize and apply.

Therefore, this specific embodiment has the characteristics of low cost, resource saving and environmental friendliness, and the prepared coal-fired additive is easy to use, has good combustion effect and is easy to popularize and apply, and is suitable for kilns in the cement industry.

Claims (2)

1. A preparation method for coal-fired additives, characterized in that the raw materials and contents thereof of the coal-fired additives are: catalyst is 40~55wt%, oxidizer is 25~35wt%, sodium chloride is 10~20wt%, five Sodium metasilicate in water is 2~6wt%, sodium lignosulfonate is 0.05~0.15wt%; According to the raw materials and contents of the coal-fired additives: earlier, sodium lignosulfonate is dissolved in water according to the solid-to-liquid mass ratio of 1: (2 ~ 4) to obtain a grinding aid solution; the prepared grinding aid The solution is evenly sprayed on the surface of the catalyst, and then the catalyst sprayed with the grinding aid solution is ground in a ball mill until the particle size is less than 100 μm to obtain a ground fine powder; then the ground fine powder is mixed with an oxidizing agent, sodium chloride, five Sodium metasilicate water is mixed with water 2 to 4 times the mass of the raw material, and stirred at a high speed on a shear mixer to obtain a coal-fired additive; In the catalyst: steel slag is 25-35wt%, steelmaking desulfurization slag is 10-20wt%, cold-rolled iron oxide slag is 20-30wt%, chromium slag is 5-15wt%, manganese tailings is 5-15wt%, Manganese dioxide is 5 ~ 10wt%; Among the oxidizing agents: potassium permanganate is 45-55wt%, and potassium perchlorate is 45-55wt%. 2. A coal-burning additive, characterized in that the coal-burning additive is a coal-burning additive prepared according to the preparation method of the coal-burning additive described in claim 1.