阅读说明：本技术 一种电厂脱硫脱硝用硅溶胶粘结剂及其制备方法 (Silica sol binder for desulfurization and denitrification of power plant and preparation method thereof ) 是由 黄方方 沈寒晰 张存社 成西涛 王前进 吴素芳 孟璐 于 2019-11-25 设计创作，主要内容包括：本发明公开一种电厂脱硫脱硝用硅溶胶粘结剂,包括以下重量份的原料：硅溶胶120份,改性组合物10.5-16.5份,甲醇10-15份,其中,所述硅溶胶由亲水气相二氧化硅、分散剂、去离子水组成,且所述硅溶胶中二氧化硅的含量为10-20wt%、分散剂的含量为0.5 wt%；所述改性组合物由质量比为(10-12)：(1-3)：0.5的甲基三甲氧基硅烷、固化促进剂、硅烷偶联剂组成；同时,本发明还公开所述粘结剂的制备方法。本发明提供的硅溶胶粒径分布窄,性能稳定,成膜性能、耐热、耐候性优异,适合作为电厂脱硫脱硝用粘结剂。(The invention discloses a silica sol binder for desulfurization and denitrification of a power plant, which comprises the following raw materials in parts by weight: 120 parts of silica sol, 10.5-16.5 parts of modified composition and 10-15 parts of methanol, wherein the silica sol consists of hydrophilic fumed silica, a dispersing agent and deionized water, and the silica content in the silica sol is 10-20wt% and the dispersing agent content is 0.5 wt%; the modified composition is prepared from the following components in percentage by mass (10-12): (1-3): 0.5 of methyl trimethoxy silane, a curing accelerator and a silane coupling agent; meanwhile, the invention also discloses a preparation method of the adhesive. The silica sol provided by the invention has the advantages of narrow particle size distribution, stable performance, excellent film-forming performance, heat resistance and weather resistance, and is suitable for being used as a binder for desulfurization and denitrification in a power plant.)

1. The utility model provides a power plant SOx/NOx control uses silica sol binder which characterized in that: the feed comprises the following raw materials in parts by weight:

120 parts of silica sol, namely 120 parts of silica sol,

10.5 to 16.5 portions of modified composition,

10-15 parts of methanol, and the like,

the silica sol consists of hydrophilic fumed silica, a dispersing agent and deionized water, wherein the silica sol contains 10-20wt% of silica and 0.5wt% of dispersing agent;

the modified composition is prepared from the following components in percentage by mass (10-12): (1-3): 0.5 of methyl trimethoxy silane, a curing accelerator and a silane coupling agent.

2. The silica sol binder for desulfurization and denitrification of power plants according to claim 1, wherein: the curing accelerator is at least one of amino alcohol, alpha-hydroxycarboxylic acid, alkali metal and/or alkaline earth metal thiocyanate and/or alkaline earth metal halide, glycerol and/or glycerol derivative.

3. The silica sol binder for desulfurization and denitrification of power plants according to claim 2, wherein: the curing accelerator is prepared from the following components in percentage by mass (10-20): 1 glycerol and an alkaline earth metal thiocyanate.

4. The silica sol binder for desulfurization and denitrification of power plants according to claim 2, wherein: the curing agent is an amino alcohol.

5. The silica sol binder for desulfurization and denitrification of power plants according to claim 2, wherein: the curing agent is alkaline earth metal thiocyanate.

6. The silica sol binder for desulfurization and denitrification of power plants according to claim 2 or 4, which is characterized in that: the amino alcohol is N-methyldiethanolamine.

7. The silica sol binder for desulfurization and denitrification of power plants according to claim 2, 3 or 5, wherein: the alkaline earth metal thiocyanate is NaSCN.

8. The silica sol binder for desulfurization and denitrification of power plants according to claim 1, wherein: the silane coupling agent is KH550 or KH 570.

9. The silica sol binder for desulfurization and denitrification of power plants according to claim 1, wherein: the dispersing agent is any one of sodium hexametaphosphate, sodium tripolyphosphate, citric acid or polyethylene glycol 400.

10. The preparation method of the silica sol binder for desulfurization and denitrification of power plants according to claim 1, 2, 3, 4, 5, 8 or 9, is characterized in that: the method comprises the following steps:

(1) preparing a silica sol solution: adding hydrophilic fumed silica into deionized water, then adding a dispersing agent, stirring for 1h at 60 ℃, and cooling to obtain silica sol with the silica content of 10-20 wt%;

(2) preparation of modified composition: mixing methyltrimethoxysilane, a curing accelerator and a silane coupling agent, and heating and stirring at 30 ℃ for 30min to obtain a composition A;

(3) adding the composition A into the silica sol obtained in the step (1), adjusting the pH value to 6-7 by using hydrochloric acid, sulfuric acid or acetic acid, and stirring and reacting for 60min at the temperature of 60 ℃;

(4) and (4) adding methanol into the product obtained in the step (3), stirring for 5min, and adjusting the viscosity of the system to be 58-62cps at 25 ℃.

Technical Field

The invention relates to the field of preparation of silica sol binders, and particularly relates to a silica sol binder for desulfurization and denitrification of a power plant and a preparation method thereof.

Background

The desulfurization and denitrification catalyst of the power plant is generally inorganic metal or non-metallic oxide, is mostly powdery particles, and can be generally fixed and loaded in order to facilitate engineering use, so that the catalyst is effectively utilized, and the catalytic efficiency and the service life of the catalyst are improved. Binders are also an essential part of the investment casting process.

With the increasing environmental requirements, some countries in the nineties have promoted the development of alcohol-based binders to water-based silica sol binders in the investment casting industry by environmental regulations of "reducing the content of air heavy organic volatile matter".

Silica sol binders have been increasingly studied in various fields. Patent CN101070161A discloses a 'method for preparing high activity composed of superfine silica particles', which uses sodium silicate solution as raw material, firstly passes through cation exchange resin and anion exchange resin, then adds acid into part of silica sol to adjust pH value to 8-11, heats to prepare seed crystal, adds another part of silica sol, and finally prepares high activity silica sol with particle size of 6-12nm, silica 10-30%, sodium oxide of 0.2-0.3% and pH value of 8.5-10.5 through ultrafiltration; the product has small particle size, the aperture of the prepared catalyst is small, the content of sodium ions is high, and the sodium ions can dissolve silicon dioxide at high temperature and collapse pore channels due to the high temperature in the catalytic process, so that the prepared catalyst cannot be used as a catalyst for desulfurization and denitrification. Patent CN101585541A discloses "a method for preparing electronic grade silica sol", which takes silica powder as raw material and comprises two steps: firstly, preparing high-purity silica sol by using silicon powder under the catalysis condition, screening by using an ion screening device, then removing impurities by controlling the flow rate of an exchange solution, and finally adding a stabilizing agent to prepare the electronic grade silica sol. The particle size of the product is 10-20nm, the solid content is about 30%, and the preparation process of silica sol is complex and is not suitable for serving as a catalyst binder due to the slow hydrolysis process of the silicon powder; the particle size is selected by utilizing the particle sieving machine, the energy consumption of the process is large, and the method is not suitable for industrial production. At present, the silica sol binder for desulfurization and denitrification of power plants is already applied industrially, but the silica sol binder has the defects of large volume shrinkage, quick drying, easy cracking of a coating film, poor leveling property and the like in a film forming process, so that the development of the silica sol binder with stable performance, controllable viscosity and simple operation is significant.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides the silica sol binder for power plant desulfurization and denitrification and the preparation method thereof.

The silica sol binder for desulfurization and denitrification of the power plant comprises the following raw materials in parts by weight:

120 parts of silica sol, namely 120 parts of silica sol,

10.5 to 16.5 portions of modified composition,

10-15 parts of methanol, and the like,

the silica sol consists of hydrophilic fumed silica, a dispersing agent and deionized water, wherein the silica sol contains 10-20wt% of silica and 0.5wt% of dispersing agent;

the modified composition is prepared from the following components in percentage by mass (10-12): (1-3): 0.5 of methyl trimethoxy silane, a curing accelerator and a silane coupling agent.

Preferably, the curing accelerator is at least one of aminoalcohols, α -hydroxycarboxylic acids, alkali and/or alkaline earth metal thiocyanates and/or alkaline earth metal halides, glycerol and/or glycerol derivatives; when the curing agent is at least two of amino alcohol, alpha-hydroxycarboxylic acid, alkali metal and/or alkaline earth metal thiocyanate and/or alkaline earth metal halide, glycerol and/or glycerol derivative, the ratio of the components is any ratio.

Preferably, the curing accelerator is prepared from the following components in a mass ratio of (10-20): 1 glycerol and an alkaline earth metal thiocyanate.

Preferably, the curing agent is an amino alcohol.

Preferably, the curing agent is an alkaline earth metal thiocyanate.

Preferably, the amino alcohol is N-methyldiethanolamine.

Preferably, the alkaline earth metal thiocyanate is NaSCN.

Preferably, the silane coupling agent is KH550 or KH 570.

Preferably, the dispersant is any one of sodium hexametaphosphate, sodium tripolyphosphate, citric acid or polyethylene glycol 400.

The preparation method of the silica sol binder for desulfurization and denitrification of the power plant comprises the following steps:

(1) preparing a silica sol solution: adding hydrophilic fumed silica into deionized water, then adding a dispersing agent, stirring for 1h at 60 ℃, and cooling to obtain silica sol with the silica content of 10-20 wt%;

(2) preparation of modified composition: mixing methyltrimethoxysilane, a curing accelerator and a silane coupling agent, and heating and stirring at 30 ℃ for 30min to obtain a composition A;

(3) adding the composition A into the silica sol obtained in the step (1), adjusting the pH value to 6-7 by using hydrochloric acid, sulfuric acid or acetic acid, and stirring and reacting for 60min at the temperature of 60 ℃;

(4) and (4) adding methanol into the product obtained in the step (3), stirring for 5min, and adjusting the viscosity of the system to be 58-62cps at 25 ℃.

The invention has the advantages that:

1. the silica sol provided by the invention has narrow particle size distribution, accounts for 70-80% of the total number of the silica sol distributed in the range of 20-30nm, has stable performance, can control the viscosity of the silica sol through the amount of methanol, and is suitable for being used as a binder for desulfurization and denitrification of a power plant;

2. after the methyl trimethoxy silane, the curing accelerator and the silane coupling agent are adopted to coat and modify the silica sol, the film forming property, the heat resistance and the weather resistance of the product are greatly improved.

Detailed Description