Denitration agent and preparation method thereof

Abstract

The invention belongs to the technical field of flue gas denitration, and particularly relates to a denitration agent and a preparation method thereof, the denitration agent comprises the following raw materials by weight: 1-3 parts of a hindered amine stabilizer, 0.1-0.5 part of a nitrite corrosion inhibitor, and 90-100 parts of ammonium carbamate. The denitration agent has the beneficial effects that the denitration agent is high in ammonia preparation efficiency, relatively high in stability, low in corrosivity, relatively easy to store and transport and suitable for flue gas denitration, and the flue gas denitration cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of flue gas denitration, and particularly relates to a denitration agent and a preparation method thereof. Background Art

[0002] The main denitrification agents currently used in the field of flue gas denitrification include ammonia water, liquid ammonia, urea, etc. Compared with liquid ammonia and ammonia water, urea is widely used as a reducing agent in the denitrification and ammonia production process. Although the technology of urea ammonia production for power plant denitrification is relatively mature, it still has problems such as high cost, high energy consumption, and easy blockage of the system. The application process of urea production, hydrolysis and pyrolysis ammonia production not only consumes large-scale energy, but also leads to a situation of competing for resources with agricultural demand. Therefore, the research and development of new and efficient denitrification and ammonia production raw materials to replace urea is of great significance to the flue gas environmental protection industry and the environmental protection system of the entire society.

[0003] As an intermediate in urea production, ammonium carbamate has better decomposition performance and cost advantages than urea. When used to replace urea in the ammonia production process, it has the advantages of high decomposition efficiency, fast rate, high denitrification efficiency, low cost and low comprehensive energy consumption. However, ammonium carbamate has the disadvantages of easy decomposition and instability, and it is relatively corrosive. Summary of the invention

[0004] The present application provides a denitrification agent and a preparation method thereof, aiming to solve the problems of strong corrosiveness, high cost and low denitrification efficiency of existing denitrification agents.

[0005] In a first aspect, the present application provides a desulfurization agent, comprising the following raw materials in parts by weight: 1-3 parts of a hindered amine stabilizer, 0.1-0.5 parts of a nitrite corrosion inhibitor, and 90-100 parts of ammonium carbamate.

[0006] According to some embodiments of the desulfurization agent described in the present application, the following raw materials are included in parts by weight: 1.5-2.3 parts of hindered amine stabilizer, 0.2-0.4 parts of nitrite corrosion inhibitor and 90-100 parts of ammonium carbamate.

[0007] According to some embodiments of the de-salting agent described in the present application, the hindered amine stabilizer includes a tetrapiperidine derivative.

[0008] According to some embodiments of the desalting agent described in the present application, the tetrapiperidine derivatives include tetramethylpiperidinol and / or 4-piperidinol.

[0009] According to some embodiments of the desalting agent described in the present application, the tetrapiperidine derivative is tetramethylpiperidinol.

[0010] According to some embodiments of the denitrification agent described in the present application, the nitrite corrosion inhibitor includes sodium nitrite and / or potassium nitrite.

[0011] The second aspect of the present application provides a method for preparing the denitrification agent according to the first aspect of the present application, comprising the following steps:

[0012] (1) mixing the hindered amine stabilizer, the nitrite corrosion inhibitor and ammonium carbamate to obtain a mixture;

[0013] (2) Granulating and drying the mixed material to obtain the denitrification agent.

[0014] According to some embodiments of the preparation method described in the present application, in step (1), the mixing temperature is 20-40° C., and the mixing time is 30-40 min.

[0015] According to some embodiments of the preparation method described in the present application, the drying temperature is 60-80° C., and the drying time is 50-70 min.

[0016] The beneficial effects of the present application include: the denitrification agent described in the present application has high ammonia production efficiency, high stability, low corrosiveness, and is relatively easy to store and transport, is suitable for flue gas denitrification, and reduces the cost of flue gas denitrification. DETAILED DESCRIPTION

[0017] Embodiments of the present invention are described in detail below. The examples of the embodiments are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0018] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0019] The embodiment of the present application provides a denitrification agent, comprising the following raw materials in parts by weight: 1-3 parts of a hindered amine stabilizer, 0.1-0.5 parts of a nitrite corrosion inhibitor, and 90-100 parts of ammonium carbamate.

[0020] The hindered amine stabilizer included in the denitrification agent described in the present application has a very strong free radical capture ability, can neutralize and stabilize free radicals, and prevent polymer chain breakage reactions caused by free radicals. In addition, the hindered amine stabilizer also has regeneration ability, that is, it can restore its own stability after the free radical capture reaction, so as to continue to play a role.

[0021] Nitrite corrosion inhibitor can maintain stable properties under different storage conditions and is an economical corrosion inhibitor.

[0022] The denitrification agent described in the present application organically combines hindered amine stabilizers, nitrite corrosion inhibitors and ammonium carbamate, so that the denitrification agent has good anti-corrosion effect, high stability and high ammonia production efficiency.

[0023] In some embodiments of the present application, the following raw materials are included in parts by weight: 1.5-2.3 parts of hindered amine stabilizer, 0.2-0.4 parts of nitrite corrosion inhibitor and 90-100 parts of ammonium carbamate.

[0024] In some embodiments of the present application, the hindered amine stabilizer includes a tetrapiperidine derivative.

[0025] In some embodiments of the present application, the tetrapiperidinol derivatives include tetramethylpiperidinol and / or 4-piperidinol.

[0026] In some embodiments of the present application, the tetrapiperidinyl derivative is tetramethylpiperidinol.

[0027] In some embodiments of the present application, the nitrite corrosion inhibitor includes sodium nitrite and / or potassium nitrite.

[0028] The present application also provides a method for preparing the denitrification agent according to the first aspect of the present application, comprising the following steps:

[0029] (1) mixing the hindered amine stabilizer, the nitrite corrosion inhibitor and ammonium carbamate to obtain a mixture;

[0030] (2) Granulating and drying the mixed material to obtain the denitrification agent.

[0031] The preparation method described in the present application uses simple raw materials and has low cost. Due to the characteristics of the raw materials, the preparation can be completed at a lower temperature and in a shorter time, and the overall preparation efficiency is high and the cost is low.

[0032] In some embodiments of the present application, in step (1), the mixing temperature is 20-40°C, for example, 20°C, 25°C, 28°C, 30°C, 35°C, 40°C, etc., and the mixing time is 30-40min, for example, 30min, 35min, 40min, etc.

[0033] In some embodiments of the present application, the drying temperature is 60-80°C, for example, 60°C, 65°C, 72°C, 78°C, 80°C, etc., and the drying time is 50-70min, for example, 50min, 55min, 58min, 60min, 67min, 70min, etc.

[0034] The technical solution of the present application is further described below in conjunction with some specific embodiments.

[0035] Example 1

[0036] A denitrifying agent comprises the following raw materials in parts by weight: 1 g of tetramethyl piperidinol, 0.1 g of sodium nitrite and 90 g of ammonium carbamate.

[0037] The preparation method of the denitrifier described in Example 1 comprises the following steps: mixing tetramethylpiperidinol, sodium nitrite and ammonium carbamate at a temperature of 30°C for 30 minutes to obtain a mixture, granulating the mixture, and then drying it at a temperature of 60°C for 30 minutes to obtain the denitrifier.

[0038] Example 2

[0039] A denitrifying agent comprises the following raw materials in parts by weight: 1 g of tetramethyl piperidinol, 0.1 g of potassium nitrite and 90 g of ammonium carbamate.

[0040] The preparation method of the denitrifier described in Example 2 comprises the following steps: mixing tetramethylpiperidinol, potassium nitrite and ammonium carbamate at a temperature of 30°C for 30 minutes to obtain a mixture, granulating the mixture, and then drying it at a temperature of 60°C for 30 minutes to obtain the denitrifier.

[0041] Example 3

[0042] A denitrifying agent comprises the following raw materials in parts by weight: 1 g of 4-piperidinol, 0.1 g of potassium nitrite and 90 g of ammonium carbamate.

[0043] The preparation method of the denitrifier described in Example 3 includes the following steps: mixing 4-piperidinol, potassium nitrite and ammonium carbamate at a temperature of 30°C for 30 minutes to obtain a mixture, granulating the mixture, and then drying it at a temperature of 60°C for 30 minutes to obtain the denitrifier.

[0044] Example 4

[0045] The denitrification agent described in Example 4 is different from the denitrification agent described in Example 1 only in that the amount of tetramethylpiperidinol added during the preparation of the denitrification agent described in Example 4 is 2 g.

[0046] Example 5

[0047] The denitrification agent described in Example 5 is different from the denitrification agent described in Example 1 only in that the amount of tetramethylpiperidinol added during the preparation of the denitrification agent described in Example 5 is 3 g.

[0048] Example 6

[0049] The only difference between the denitrification agent described in Example 6 and the denitrification agent described in Example 1 is that the amount of sodium nitrite added during the preparation of the denitrification agent described in Example 6 is 0.2 g.

[0050] Example 7

[0051] The only difference between the denitrification agent described in Example 7 and the denitrification agent described in Example 1 is that the amount of sodium nitrite added during the preparation of the denitrification agent described in Example 7 is 0.3 g.

[0052] Example 8

[0053] The only difference between the denitrification agent described in Example 8 and the denitrification agent described in Example 1 is that the amount of sodium nitrite added during the preparation of the denitrification agent described in Example 8 is 0.5 g.

[0054] Comparative Example 1

[0055] The denitrification agent described in Comparative Example 1 is different from the denitrification agent described in Example 1 only in that lead stearate is used instead of tetramethyl piperidine alcohol stabilizer during the preparation process of the denitrification agent described in Comparative Example 1.

[0056] Comparative Example 2

[0057] The denitrification agent described in Comparative Example 2 is different from the denitrification agent described in Example 1 only in that sodium silicate is used instead of sodium nitrite corrosion inhibitor during the preparation process of the denitrification agent described in Comparative Example 2.

[0058] Comparative Example 3

[0059] The denitrification agent described in Comparative Example 3 is different from the denitrification agent described in Example 1 only in that methyl benzoate is used instead of sodium nitrite corrosion inhibitor during the preparation process of the denitrification agent described in Comparative Example 3.

[0060] Comparative Example 4

[0061] The denitrification agent described in Comparative Example 4 is different from the denitrification agent described in Example 1 only in that the raw material tetramethylpiperidinol is not added during the preparation process of the denitrification agent described in Comparative Example 4.

[0062] Performance study of the denitrifiers described in Examples 1-8 and Comparative Examples 1-4 of the present application

[0063] 1. The denitrification agents described in Examples 1-8 and Comparative Examples 1-4 of the present application were prepared into solutions with a concentration of 50%, and the stability of the above denitrification agents was tested at a temperature of 50° C. The test results are shown in Table 1.

[0064] Table 1

[0065]

[0066]

[0067] It can be seen from Table 1 that the use of the tetramethylpiperidine derivative proposed in the present application as a stabilizer can significantly improve the stability of the denitrification agent based on ammonium carbamate, and the greater the added amount, the better the stability.

[0068] 2. The denitrification agents described in Examples 1-8 and Comparative Examples 1-4 of the present application were prepared into solutions with a mass concentration of 50%, and then 5 g of samples of 304 material were immersed in the corresponding solutions at 30°C for 6 months. The weight change of the samples before and after immersion was calculated to evaluate the corrosiveness of the denitrification agents described in Examples 1-8 and Comparative Examples 1-4. The results are shown in Table 2.

[0069] Table 2

[0070] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Weight change before and after soaking (g) -0.081 -0.079 -0.075 -0.127 -0.136 -0.072 Example 7 Example 8 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Weight change before and after soaking (g) -0.070 -0.053 -0.139 -0.105 -0.097 -0.076

[0071] It can be seen from Table 2 that the use of the nitrate proposed in the present application as a corrosion inhibitor can significantly reduce the corrosiveness of the denitrification agent based on ammonium carbamate, and the greater the amount added, the better the reduction effect.

[0072] 3. The denitrification agents described in Examples 1-8 and Comparative Examples 1-4 of the present application were prepared into solutions with a mass concentration of 50%, and the ammonia production efficiency of the above denitrification agents was tested at a temperature of 300°C, wherein the ammonia production efficiency = measured NH 3 Concentration / theoretical complete decomposition of NH 3 The concentrations are shown in Table 3.

[0073] Table 3

[0074] Example 1 Example 2 Example 3 Example 4 Example 5 Ammonia production efficiency (%) 98.5 99.7 98.9 99.3 99.3 Example 6 Example 7 Example 8 Urea Ammonia production efficiency (%) 99.8 99.6 99.2 45

[0075] Although the above embodiments have been shown and described, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. Changes, modifications, substitutions and variations of the above embodiments by those of ordinary skill in the art are all within the scope of protection of the present invention.

Claims

1. A desalting agent, characterized in that: The invention comprises the following raw materials in parts by weight: 1-3 parts of hindered amine stabilizer, 0.1-0.5 parts of nitrite corrosion inhibitor and 90-100 parts of ammonium carbamate.

2. The desalting agent according to claim 1, characterized in that The invention comprises the following raw materials in parts by weight: 1.5-2.3 parts of hindered amine stabilizer, 0.2-0.4 parts of nitrite corrosion inhibitor and 90-100 parts of ammonium carbamate.

3. The desalting agent according to claim 1, characterized in that: The hindered amine stabilizer includes tetrapiperidine derivatives.

4. The liquid-removing agent according to claim 3, characterized in that: The tetrapiperidinol derivatives include tetramethylpiperidinol and / or 4-piperidinol.

5. The denitrification agent according to claim 4, characterized in that: The tetrapiperidine derivative is tetramethylpiperidinol.

6. The liquid-removing agent according to claim 3, characterized in that: The nitrite corrosion inhibitor includes sodium nitrite and / or potassium nitrite.

7. The method for preparing the desulfurization agent according to any one of claims 1 to 6, characterized in that: The following steps are involved: (1) mixing the hindered amine stabilizer, the nitrite corrosion inhibitor and ammonium carbamate to obtain a mixture; (2) Granulating and drying the mixed material to obtain the denitrification agent.

8. The method for preparing the desalting agent according to claim 7, characterized in that: In step (1), the mixing temperature is 20-40° C., and the mixing time is 30-40 min.

9. The method for preparing the desalting agent according to claim 7, characterized in that: The drying temperature is 60-80° C., and the drying time is 50-70 min.

Images