Stable denitration agent and application thereof

Abstract

The present application belongs to the technical field of flue gas denitration, and particularly relates to a stable denitration agent and application thereof. The stable denitration agent disclosed in the present application comprises ammonium bicarbonate and a stabilizer, wherein the stabilizer comprises an alcohol amide compound. The stable denitration agent has the characteristics of high ammonia production efficiency, low ammonia production energy consumption, easy storage of the prepared denitration agent solution, low corrosiveness, no toxic and harmful components to the denitration system, and low thermal decomposition temperature, and is suitable for application in the field of flue gas denitration and the like.

Description

Technical Field

[0001] This invention belongs to the field of flue gas denitrification technology, specifically relating to a stable denitrification agent and its application. Background Technology

[0002] NO X As a harmful gas produced in industrial processes such as thermal power, ceramics and glass, coking, and cement, NO2 in flue gas poses a significant threat to the normal atmospheric environment, directly causing acid rain and toxic smog. Therefore, the control of NO2 in flue gas during production facilities is crucial. X With significant limitations, denitrification becomes particularly important. In recent years, traditional NO removal methods used in the thermal power, coking, cement, and ceramics / glass industries have become increasingly inadequate. X Methods include SNCR and SCR. All of these methods require corresponding denitrification reducing agents.

[0003] Driven by the need for energy conservation and emission reduction, the development of flue gas denitrification technology has also ushered in a new opportunity. From both an environmental protection perspective and an economic perspective, developing efficient and stable denitrification agents and their ammonia production technology to improve ammonia production efficiency, enhance the economics of denitrification, and reduce energy consumption and overall costs is of paramount importance. Summary of the Invention

[0004] This invention is based on the inventor's discoveries and understanding of the following facts and problems:

[0005] The selection of denitrification reducing agents is generally based on a comprehensive consideration of their physical properties, economy, and safety. Currently, there are three main types: liquid ammonia, ammonia water, and urea.

[0006] Liquid ammonia is a hazardous chemical. With the increasing emphasis on safety by the state and the gradual introduction of a series of related restrictive measures, the use of liquid ammonia in power plants has been subject to more and more constraints in terms of approval, construction period, and land occupation. The environmental protection acceptance process after commissioning is also quite complicated. Over the years, due to improper use, the casualties and losses caused by liquid ammonia have been very heavy.

[0007] Using ammonia water as a reducing agent involves evaporating a 25% ammonia-containing aqueous solution through a heating device to form ammonia gas and water vapor. The ammonia gas is then diluted with air and sent into the flue gas for denitrification. This denitrification system requires matching with large ammonia water storage equipment and ammonia water evaporators.

[0008] Urea is a solid substance that is safe, harmless, and easy to operate and store. However, urea solution is corrosive to containers, adding a urea dissolution system to the system and making it more complex. Urea-to-ammonia production requires first preparing a low-concentration urea solution, operating under high temperature and pressure conditions, resulting in high system energy consumption and a large equipment footprint.

[0009] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, embodiments of this invention propose a stable denitrification agent, which possesses characteristics such as good stability, low ammonia production energy consumption, easy storage of the prepared denitrification agent solution, low corrosivity, absence of toxic or harmful components to the denitrification system, and low thermal decomposition temperature, making it suitable for applications in flue gas denitrification and other fields.

[0010] The stabilizing denitrification agent of this invention includes ammonium bicarbonate and a stabilizer; wherein the stabilizer includes an alcohol amide compound.

[0011] The advantages and technical effects of the stabilizing denitrification agent in this invention are as follows: 1. The stabilizing denitrification agent in this invention uses ammonium bicarbonate as the main raw material. Ammonium bicarbonate can decompose in large quantities at around 30°C, resulting in higher ammonia production efficiency. Moreover, it is widely available and readily available, which can significantly reduce the cost of flue gas denitrification. 2. The stabilizing denitrification agent in this invention uses alcohol amide compounds as stabilizers. Alcohol amide compounds have both lipophilic and hydrophilic properties, and can form micron-sized micelles in water. The amphoteric interface can form a high-strength film to inhibit the decomposition of ammonium bicarbonate, giving the denitrification agent solution good stability and meeting storage requirements.

[0012] In some embodiments, the alcohol amide compound includes at least one of branched alcohol amide compounds or linear alcohol amide compounds, wherein the branched alcohol amide compound includes polyisobutylene maleic acid diethanolamide, and the linear alcohol amide compound includes at least one of oleic acid diethanolamide and stearic acid diethanolamide.

[0013] In some embodiments, the amount of the alcohol amide compound used is 1 to 3 wt% of the ammonium bicarbonate.

[0014] In some embodiments, the stabilizing denitrification agent further includes a corrosion inhibitor.

[0015] In some embodiments, the corrosion inhibitor includes at least one of thiadiazole derivatives, nitrites, and benzotriazole derivatives.

[0016] In some embodiments, the thiadiazole derivative includes at least one of thiadiazole, thiadiazole acetylimide, and thiadiazole propionylimide; the nitrite includes at least one of sodium nitrite, calcium nitrite, and magnesium nitrite; and the benzotriazole derivative includes at least one of benzotriazole, benzotriazole isobutylimide, and benzotriazole propionylimide.

[0017] In some embodiments, the amount of the corrosion inhibitor is 0.1 to 0.6 wt% of the ammonium bicarbonate.

[0018] The present invention also provides an application of the above-mentioned stabilized denitrification agent in the field of flue gas denitrification.

[0019] In some embodiments, the application includes formulating the stabilized denitrification agent into a solution with a concentration of 30-50%. Detailed Implementation

[0020] The embodiments of the present invention are described in detail below. These embodiments are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0021] The stabilizing denitrification agent of this invention includes ammonium bicarbonate and a stabilizer; wherein the stabilizer includes an alcohol amide compound.

[0022] The stabilizing denitrification agent in this invention uses ammonium bicarbonate as the main raw material. Ammonium bicarbonate can decompose in large quantities at around 30°C, resulting in higher ammonia production efficiency. It is also widely available and readily accessible, which can significantly reduce the cost of flue gas denitrification. The stabilizing denitrification agent in this invention uses alcohol amide compounds as stabilizers. Alcohol amide compounds have both lipophilic and hydrophilic properties, and can form micron-sized micelles in water. The amphoteric interface can form a high-strength film to inhibit the decomposition of ammonium bicarbonate, giving the denitrification agent solution good stability and meeting storage requirements.

[0023] In some embodiments, preferably, at least one of a branched alcohol amide compound or a linear alcohol amide compound, wherein the branched alcohol amide compound includes polyisobutylene maleate diethanolamide, and the linear alcohol amide compound includes at least one of oleic acid diethanolamide and stearic acid diethanolamide. More preferably, the amount of the alcohol amide compound is 1-3 wt% of the ammonium bicarbonate.

[0024] In this embodiment of the invention, the types and amounts of alcohol amide compounds are preferred, which can make the solution prepared by the stabilized denitrification agent have good stability, while keeping the production cost within a reasonable range. If the amount of stabilizer is too low, it will not be conducive to improving the stability of the denitrification agent solution; if the amount of stabilizer is too high, it will increase the production cost.

[0025] In some embodiments, preferably, the stabilizing denitrification agent further includes a corrosion inhibitor. More preferably, the corrosion inhibitor includes at least one selected from thiadiazole derivatives, nitrites, and benzotriazole derivatives (TTA). Even more preferably, the thiadiazole derivative includes at least one selected from thiadiazole, thiadiazole acetylimide, and thiadiazole propionylimide; the nitrite includes at least one selected from sodium nitrite, calcium nitrite, and magnesium nitrite; and the benzotriazole derivative includes at least one selected from benzotriazole, benzotriazole isobutylimide, and benzotriazole propionylimide.

[0026] In this embodiment of the invention, a corrosion inhibitor is further added to the denitrification agent, and the type of corrosion inhibitor is preferred. This corrosion inhibitor can significantly inhibit the corrosiveness of ammonium bicarbonate to the equipment, reduce the cost of equipment maintenance, and ensure the long-term stable operation of the preparation process.

[0027] In some embodiments, preferably, the amount of corrosion inhibitor is 0.1 to 0.6 wt% of the ammonium bicarbonate.

[0028] In this embodiment of the invention, the dosage of corrosion inhibitor is further optimized, which can significantly inhibit the corrosiveness of ammonium bicarbonate to equipment, while keeping production costs within a reasonable range.

[0029] The present invention also provides an application of the above-mentioned stabilized denitrification agent in the field of flue gas denitrification.

[0030] In some embodiments, the application includes formulating the stabilized denitrification agent into a solution with a concentration of 30-50%.

[0031] The technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0032] Example 1

[0033] Ammonium bicarbonate is prepared by passing carbon dioxide gas into concentrated ammonia water. At the same time, polyisobutylene maleic acid diethanolamide stabilizer and pyridazol acetylimide corrosion inhibitor are added. After filtration and drying, denitrification agent is obtained. The amount of polyisobutylene maleic acid diethanolamide added is 1 wt% of ammonium bicarbonate and the amount of pyridazol acetylimide added is 0.3 wt%.

[0034] Example 2

[0035] The preparation method of this embodiment is the same as that of Example 1, except that the amount of polyisobutylene maleic acid diethanolamide added is 2 wt% of ammonium bicarbonate.

[0036] Example 3

[0037] The preparation method of this embodiment is the same as that of Example 1, except that the amount of polyisobutylene maleic acid diethanolamide added is 3 wt% of ammonium bicarbonate.

[0038] Example 4

[0039] The preparation method of this embodiment is the same as that of Example 1, except that the amount of thiazolidinediolide added is adjusted to 0.1wt%, 0.2wt%, 0.4wt%, 0.5wt%, and 0.6wt%.

[0040] Example 5

[0041] The preparation method of this embodiment is the same as that of Example 1, except that the alcohol amide stabilizer used is oleic acid diethanolamide.

[0042] Comparative Example 1

[0043] The preparation method of this comparative example is the same as that of Example 1, except that triethanolamine acetate is used as a stabilizer.

[0044] Comparative Example 2

[0045] This comparative example uses only ammonium bicarbonate as a denitrification agent.

[0046] Comparative Example 3

[0047] This comparative example uses only urea as a denitrification agent.

[0048] Performance testing

[0049] 1. Stability

[0050] (1) The denitrifying agents prepared in Examples 1-3 and Comparative Examples 1-3 were all prepared into solutions with a concentration of 50%. After being placed at 50°C for a period of time, the content of ammonium bicarbonate in the solution was measured and the loss rate was calculated to evaluate the stability of the denitrifying agent solution. The results are shown in Table 1.

[0051] Table 1. Changes in loss rate (%) over time

[0052] 24h 48h 72h 96h 120h 144h 168h Example 1 2.5 5.2 6.9 8.6 11.3 14.1 15.7 Example 2 1.7 3.6 4.3 8.1 8.7 11.9 12.5 Example 3 0.3 0.5 1.1 1.7 3.2 5.5 6.8 Comparative Example 1 2.6 6.7 9.1 11.8 15.2 17.6 20.7 Comparative Example 2 3.3 5.8 9.5 13.7 17.9 22.4 26.0 Comparative Example 3 5.0 5.8 6.0 6.1 6.1 6.1 6.2

[0053] As shown in Table 1, the loss rate of the urea-prepared solution was 5.0% after 24 hours, gradually increasing and stabilizing over time, reaching only 6.2% after 168 hours. The loss rate of the ammonium bicarbonate-prepared solution was 3.3% after 24 hours, gradually increasing over time, reaching 26.0% after 168 hours. Comparative Example 1, which added triethanolamine acetate as a stabilizer to ammonium bicarbonate, showed some improvement in stability compared to Comparative Example 2, but the loss rate still reached 20.7% after 168 hours, failing to meet the requirements. Examples 1-3, which added alcohol amide as a stabilizer to ammonium bicarbonate, showed a significant improvement in the stability of the denitrification agent solution, with the stability gradually increasing with increasing alcohol amide dosage.

[0054] (2) The denitrifying agents prepared in Examples 1 and 5 were prepared into a 50% solution. After being placed at 50°C for a period of time, the content of ammonium bicarbonate in the solution was measured and the loss rate was calculated to evaluate the effect of different alcohol amide structures on stability. The loss rates are shown in Table 2.

[0055] Table 2. Changes in loss rate (%) over time

[0056] Time (h) Example 1 Example 5 24 2.5 2.5 48 5.2 5.3 72 6.9 7.0 96 8.6 9.4 120 11.3 11.8 144 14.1 13.9 168 15.7 16.6

[0057] As can be seen from the data in Table 2, branched-chain alcohol amides have a better inhibitory effect on the decomposition of ammonium bicarbonate compared with straight-chain alcohol amides. This is because the branched-chain group structure has higher interfacial stability than the straight-chain structure, which can greatly inhibit the volatilization of ammonia generated by hydrolysis, thereby inhibiting the forward hydrolysis reaction and improving the stability of the denitrification agent solution.

[0058] 2. Ammonia production efficiency

[0059] (1) The denitrification agents prepared in Example 1, Comparative Example 2 and Comparative Example 3 were prepared into solutions with a concentration of 50%, and the ammonia production efficiency at different temperatures was tested. The ammonia production efficiency was calculated as the measured NH3 concentration / the theoretically completely decomposed NH3 concentration. The results are shown in Table 3.

[0060] Table 3

[0061] Temperature (°C) Example 1 Comparative Example 2 Comparative Example 3 200 98.44％ 98.45％ 9.59％ 250 98.25％ 98.21％ 10.58％ 300 98.35％ 98.32％ 30.66％ 350 98.40％ 98.35％ 38.93％ 400 98.60％ 98.56％ 88.02％ 450 98.90％ 98.94％ 90.90％

[0062] As can be seen from the data in Table 3, the ammonia production efficiency of the denitrification agent reached 98.44% at 200℃, and remained between 98% and 99% thereafter with little change in temperature; while the ammonia production efficiency of urea was only 9.59% at 200℃ and 90.90% at 450℃. It can be seen that the ammonia production temperature of the denitrification agent in this embodiment of the invention can be more than 200℃ lower than that of urea.

[0063] (2) The denitrification agents prepared in Examples 1 and 4 were prepared into a 50% solution. The ammonia production efficiency of the denitrification agents prepared in Examples 1 and 4 was tested at 400°C to explore the effect of different corrosion inhibitor addition amounts on the ammonia production efficiency. The results are shown in Table 4.

[0064] Table 4

[0065] TTA addition amount 0.1wt% 0.2wt% 0.3wt% 0.4wt% 0.5wt% 0.6wt% Ammonia production efficiency (%) 98.74 98.50 98.60 98.70 98.66 98.73

[0066] As can be seen from the data in Table 4, the amount of corrosion inhibitor TTA does not have a significant impact on the ammonia production efficiency of the denitrification agent.

[0067] (3) The solutions of Example 1 and Comparative Example 3 were prepared into 50% solutions. The effects of different residence times in the equipment at different temperatures on the ammonia production efficiency were studied. The results are shown in Table 5.

[0068] Table 5

[0069]

[0070] As can be seen from the data in Table 5, at the same temperature, the ammonia production efficiency of the denitrification agents prepared in Example 1 and Comparative Example 3 both increased with the extension of residence time in the equipment; and at the same residence time, the ammonia production efficiency of the denitrification agents prepared in Example 1 and Comparative Example 3 both increased with the increase of temperature.

[0071] 3. To investigate the effect of the denitrification agent on the equipment under long-term pyrolysis conditions, the denitrification agents prepared in Comparative Example 3 and Example 1 were continuously pyrolyzed for 24 hours. The results showed that after long-term pyrolysis, the urea in Comparative Example 3 had black deposits at the outlet during the pyrolysis period, and obvious undecomposed urea crystals at the outlet after pyrolysis. However, the device did not show black deposits or crystals after the denitrification agent in Example 1. It can be seen that the denitrification agent prepared in the embodiments of the present invention can effectively avoid the crystallization problem in the pyrolysis furnace under the same pyrolysis conditions.

[0072] 4. Corrosive

[0073] (1) The denitrification agents prepared in Example 1 and Comparative Examples 2-3 were prepared into solutions of different concentrations. Then, 10g of 304 material samples were soaked in the corresponding solutions and soaked at 60°C for 6 months. The weight change of the samples after soaking was calculated to evaluate the corrosiveness of ammonium bicarbonate and urea to metal after being prepared into different concentrations. The results are shown in Table 6.

[0074] Table 6

[0075] concentration(%) Example 1 Comparative Example 2 Comparative Example 3 10 -0.00015 -0.010 -0.0002 20 -0.00019 -0.0189 -0.0005 30 -0.00024 -0.0337 -0.0007 40 -0.00030 -0.0402 -0.0008 50 -0.00036 -0.0669 -0.0009

[0076] As can be seen from the data in Table 6, the corrosiveness of the sample increases with the increase of the denitrification agent concentration, and ammonium bicarbonate is significantly more corrosive to the sample than urea. The denitrification agent prepared in Example 1 of this invention has its corrosiveness to the sample suppressed due to the addition of a corrosion inhibitor.

[0077] (2) The series of denitrification agents prepared in Examples 1 and 4 were prepared into solutions with a concentration of 50%. Then, 10g of 304 material samples were soaked in the corresponding solutions and soaked at different temperatures for 6 months. The weight change of the samples after soaking was calculated to evaluate the effect of the amount of corrosion inhibitor added on the corrosivity. The results are shown in Table 7.

[0078] Table 7

[0079] TTA addition amount 0.1wt% 0.2wt% 0.3wt% 0.4wt% 0.5wt% 0.6wt% corrosive -0.00041 -0.00038 -0.00036 -0.00031 -0.00027 -0.00025

[0080] (3) The denitrification agents prepared in Example 1 and Comparative Example 3 were prepared into a 50% solution. Then, the 304 material samples were immersed in the corresponding solutions and immersed at different temperatures for 6 months. The weight change of the samples after immersion was calculated to evaluate the effect of different temperatures on metal corrosion. The results are shown in Table 8.

[0081] Table 8

[0082] temperature 40℃ 60℃ 80℃ 100℃ Example 1 -0.0003 -0.0002 -0.0004 -0.0003 Comparative Example 3 -0.0003 -0.0004 -0.0004 -0.0003

[0083] As can be seen from the data in Table 8, the corrosiveness of the denitrification agent to the sample did not change significantly with the increase of temperature, indicating that the corrosion inhibitor used in the embodiments of the present invention has good stability.

[0084] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0085] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the protection scope of the present invention.

Claims

1. A stabilizing denitrification agent, characterized in that, It includes ammonium bicarbonate and a stabilizer; wherein the stabilizer includes alcohol amide compounds; The alcoamide compounds are branched alcoamide compounds, including polyisobutylene maleic acid diethanolamide; The amount of the alkamide compound used is 1-3 wt% of the ammonium bicarbonate; The denitrification agent also includes a corrosion inhibitor.

2. The stabilizing denitrification agent according to claim 1, characterized in that, The corrosion inhibitor includes at least one of thiadiazole derivatives, nitrites, and benzotriazole derivatives.

3. The stabilizing denitrification agent according to claim 2, characterized in that, The thiadiazole derivative includes at least one of thiadiazole, thiadiazole acetylimide, and thiadiazole propionylimide; the nitrite includes at least one of sodium nitrite, calcium nitrite, and magnesium nitrite; and the benzotriazole derivative includes at least one of benzotriazole, benzotriazole isobutylimide, and benzotriazole propionylimide.

4. The stabilizing denitrification agent according to any one of claims 1 to 3, characterized in that, The amount of the corrosion inhibitor is 0.1 to 0.6 wt% of the ammonium bicarbonate.

5. The application of the stabilized denitrification agent according to any one of claims 1 to 4 in flue gas denitrification.

6. The application of the stabilizing denitrification agent according to claim 5 in flue gas denitrification, characterized in that, This includes preparing the denitrification agent into a solution with a concentration of 30-50%.

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