Coal combustion dispersant and its application in preparing environment-friendly liquid coal additive

Abstract

The application discloses a coal combustion dispersant and application thereof in preparation of an environment-friendly liquid coal combustion additive. A preparation method of the coal combustion dispersant comprises the following steps: S1. mixing polyvinyl alcohol, oxetane-3-methanol, a strong base catalyst and a first solvent, and performing a warming reaction to obtain a comb-shaped polymer; and S2. mixing the comb-shaped polymer, sodium di(laureth-7) citrate, a strong acid catalyst, a polymerization inhibitor and a second solvent, and performing a warming reaction to obtain the coal combustion dispersant. The coal combustion dispersant is used for preparing the environment-friendly liquid coal combustion additive. The obtained environment-friendly liquid coal combustion additive can significantly reduce pollutant emission concentration of coal combustion and improve a pollutant emission reduction rate of coal combustion.

Description

Technical Field

[0001] This invention belongs to the technical field of environmentally friendly liquid coal additives, and particularly relates to a coal dispersant and its application in the preparation of environmentally friendly liquid coal additives. Background Technology

[0002] my country is a country rich in coal, poor in oil, and lacking in natural gas. Currently, many modern industries, such as cement production, power generation, and steel smelting, use coal as fuel. However, coal combustion produces large amounts of polluting gases such as SOx and NOx, as well as soot, causing environmental pollution. To improve the severe air pollution caused by coal-fired power plants, my country has set higher requirements for the emission concentration of flue gas from key pollution sources. Therefore, improving the combustion performance of coal and reducing the polluting gases and soot produced by coal combustion is of great significance.

[0003] Environmentally friendly additives refer to a class of additives that reduce the emission concentrations of pollutants such as sulfur oxides and nitrogen oxides during coal combustion. Using environmentally friendly liquid coal combustion additives can significantly improve the environmental performance of coal. Currently, environmentally friendly liquid coal combustion additives generally use the following substances as components: 1) alkali metal, alkaline earth metal, and transition metal oxides, such as magnesium oxide and calcium oxide; 2) alkali metal, alkaline earth metal, and transition metal bases or salts, such as nitrates, carbonates, chlorates, chlorides, and certain organic acid salts; 3) oxidants, such as permanganates and potassium nitrates; 4) surfactants. The surfactants used in existing environmentally friendly liquid coal combustion additives have poor dispersing properties, making it difficult for these additives to reduce the emission concentrations of pollutants from coal combustion and improve the pollutant reduction rate. Summary of the Invention

[0004] To address the shortcomings of the existing technology, a coal combustion dispersant is provided. This dispersant contains anionic groups in its molecular structure. These anionic groups interact electrostatically with metal cations in environmentally friendly liquid coal combustion additives, such as catalysts, desulfurizing agents, and rare earth compounds. Furthermore, the dispersant contains hydroxyl groups, leading to hydrogen bonding between dispersants and between dispersants and other substances. This enhances the interaction forces between dispersants and between dispersants and other substances, significantly improving the dispersing effect of the coal combustion dispersant. Consequently, the environmentally friendly liquid coal combustion additive significantly reduces the concentration of pollutants emitted from coal combustion and increases the pollutant emission reduction rate.

[0005] The purpose of this invention is to provide a method for preparing a coal combustion dispersant, comprising the following steps:

[0006] S1. Polyvinyl alcohol, oxetane-3-methanol, a strong base catalyst and a first solvent are mixed and reacted at a higher temperature to obtain a comb-shaped polymer;

[0007] S2. The comb-shaped polymer, sodium di(lauryl ether-7) citrate, strong acid catalyst, polymerization inhibitor, and second solvent are mixed and reacted at elevated temperature to obtain a coal combustion dispersant.

[0008] The polyvinyl alcohol molecule of the present invention contains hydroxyl groups on its side chains. The hydroxyl groups of polyvinyl alcohol react with the epoxy groups of oxetane-3-methanol to obtain a comb-shaped polymer containing ether bonds and hydroxyl groups on its side chains. The terminal hydroxyl groups of the comb-shaped polymer undergo an etherification reaction with the hydroxyl groups of sodium di(lauryl ether-7) citrate to obtain a coal combustion dispersant containing hydroxyl groups, ether bonds and anionic groups in its molecular structure.

[0009] In some embodiments of the present invention, in S1, the mass ratio of polyvinyl alcohol to oxetane-3-methanol is 8:2~5.

[0010] In some embodiments of the present invention, in S1, the number-average molecular weight of the polyvinyl alcohol is 500~1800 g / mol.

[0011] In some embodiments of the present invention, in S1, the amount of alkaline catalyst used is 2000~4000 ppm of the total reaction raw materials.

[0012] In some embodiments of the present invention, in S1, the strong base catalyst includes one of potassium hydroxide, sodium hydroxide, potassium tert-butoxide, sodium tert-butoxide, sodium methoxide, sodium ethoxide, and sodium isopropoxide.

[0013] In some embodiments of the present invention, in S1, the first solvent is selected from at least one of dichloromethane, chloroform, tetrahydrofuran, toluene, 1,1-dichloroethane, 1,2-dichloroethane, and xylene.

[0014] In some embodiments of the present invention, in S1, the temperature of the heating reaction is 90~130°C and the time is 10~20 hours.

[0015] In some embodiments of the present invention, in S2, the mass ratio of the comb-shaped polymer to sodium di(lauryl ether-7) citrate is 5 to 10:1.

[0016] In some embodiments of the present invention, in S2, the mass ratio of the comb-shaped polymer, the strong acid catalyst and the polymerization inhibitor is 1:0.1~0.2:0.05~0.08.

[0017] In some embodiments of the present invention, in S2, the strong acid catalyst is selected from at least one of sulfuric acid, phosphoric acid, p-toluenesulfonic acid, and methanesulfonic acid.

[0018] In some embodiments of the present invention, in S2, the polymerization inhibitor is selected from at least one of hydroquinone, methyl hydroquinone, tert-butylhydroquinone, and 2,6-di-tert-butylhydroquinone.

[0019] In some embodiments of the present invention, in S2, the second solvent is selected from at least one of dichloromethane, chloroform, tetrahydrofuran, toluene, 1,1-dichloroethane, 1,2-dichloroethane, and xylene.

[0020] In some embodiments of the present invention, in S2, the heating reaction is to raise the temperature to 100~130°C and react for 3~6 hours.

[0021] Another object of the present invention is to provide a coal dispersant, wherein the coal dispersant is prepared by the method described above.

[0022] Another objective of this invention is to provide an environmentally friendly liquid coal additive, comprising an effective amount of the aforementioned coal dispersant.

[0023] In some embodiments of the present invention, the amount of the coal dispersant is 5-8% by weight of the environmentally friendly liquid coal additive.

[0024] In some embodiments of the present invention, the environmentally friendly liquid coal additive further includes the following raw materials in the following mass fractions: 4-10% iron oxide, 1-2.5% cerium nitrate, 0.1-0.5% calcium oxide, 0.2-0.5% ammonium bicarbonate, 2.5-4.5% potassium carbonate, 0.5-2.5% kaolin, 0.5-2% magnesium chloride, and the balance being water.

[0025] Another object of the present invention is to provide a method for preparing the aforementioned environmentally friendly liquid coal additive, comprising the following steps:

[0026] (1) Add the remaining water to the reaction vessel and stir. Add 4-10% iron oxide and 0.5-2% cerium nitrate to the reaction vessel and stir until completely dissolved to obtain mixture A;

[0027] (2) Add 0.1-0.5% calcium oxide, 0.2-0.5% ammonium bicarbonate, 2.5-4.5% potassium carbonate, 0.5-2.5% kaolin and 0.5-2% magnesium chloride to mixture A, continue stirring, and control the reaction temperature to 30-60℃ to obtain mixture B;

[0028] (3) Add 1.5-2.5% of coal dispersant to mixture B and stir at high speed for 30-60 minutes to obtain an environmentally friendly liquid coal additive.

[0029] Another object of the present invention is to provide a modified coal, comprising the aforementioned environmentally friendly liquid coal additive and coal.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The coal dispersant of this invention contains anionic groups in its molecular structure. These anionic groups interact electrostatically with metal cations in substances such as catalysts, desulfurizers, and rare earth compounds in environmentally friendly liquid coal additives. Furthermore, the coal dispersant contains hydroxyl groups in its molecular structure, resulting in hydrogen bonding between dispersants and between dispersants and other substances. This enhances the interaction forces between dispersants and between dispersants and other substances, significantly improving the dispersing effect of the coal dispersant. Consequently, the environmentally friendly liquid coal additives significantly reduce the concentration of pollutants emitted from coal combustion and increase the pollutant emission reduction rate from coal combustion. Detailed Implementation

[0032] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0033] All raw materials used in this invention are commercially available.

[0034] Example 1

[0035] This embodiment provides a coal combustion dispersant, and the specific preparation steps are as follows:

[0036] S1. Polyvinyl alcohol (8g), potassium hydroxide (0.02g), and toluene (50g) with a number average molecular weight of 500~1800g / mol were added to a reflux reactor, mixed, stirred, heated to 130℃, oxetane-3-methanol (2g) was added, stirred, and reacted for 10 hours to obtain a comb-shaped polymer.

[0037] S2. Mix the comb-shaped polymer (10g), sodium bis(lauryl ether-7) citrate (1g), p-toluenesulfonic acid (1g), hydroquinone (0.8g), and toluene (30g) dissolved in water, stir, and heat to 130℃ for 6 hours. After the reaction is completed, slowly add the crude product to ethanol to precipitate the polymer, thus obtaining the coal combustion dispersant. According to GPC testing, the number average molecular weight of the coal combustion dispersant is 4500~8000g / mol.

[0038] Example 2

[0039] This embodiment provides a coal combustion dispersant, and the specific preparation steps are as follows:

[0040] S1. Polyvinyl alcohol (8g), potassium hydroxide (0.05g), and toluene (50g) with a number average molecular weight of 500~1800g / mol were added to a reflux reactor, mixed, stirred, heated to 130℃, and oxetane-3-methanol (5g) was added. The mixture was stirred and reacted for 20 hours to obtain a comb-shaped polymer.

[0041] S2. Mix the comb-shaped polymer (10g), sodium bis(lauryl ether-7) citrate (2g), p-toluenesulfonic acid (2g), hydroquinone (0.5g), and toluene (30g) dissolved in water, stir, and heat to 130℃ for 3 hours. After the reaction is completed, slowly add the crude product to ethanol to precipitate the polymer, thus obtaining the coal combustion dispersant. According to GPC testing, the number average molecular weight of the coal combustion dispersant is 3500~6000g / mol.

[0042] Example 3

[0043] This embodiment provides an environmentally friendly liquid coal combustion additive, and the specific preparation steps are as follows:

[0044] (1) Add the remaining water to the reactor by weight percentage, stir, add 4% iron oxide and 2% cerium nitrate to the reactor, stir until completely dissolved, and obtain mixture A;

[0045] (2) Add 0.1% calcium oxide, 0.5% ammonium bicarbonate, 2.5% potassium carbonate, 2.5% kaolin and 0.5% magnesium chloride to mixture A, continue stirring, and control the reaction temperature to 30~60℃ to obtain mixture B;

[0046] (3) Add 8% of the coal dispersant prepared in Example 1 to mixture B, and stir at high speed for 30-60 minutes to obtain an environmentally friendly liquid coal additive.

[0047] Example 4

[0048] This embodiment provides an environmentally friendly liquid coal combustion additive, and the specific preparation steps are as follows:

[0049] (1) Add the remaining water to the reactor by weight percentage, stir, add 10% iron oxide and 0.5% cerium nitrate to the reactor, stir until completely dissolved, and obtain mixture A;

[0050] (2) Add 0.5% calcium oxide, 0.2% ammonium bicarbonate, 4.5% potassium carbonate, 0.5% kaolin and 2% magnesium chloride to mixture A, continue stirring, and control the reaction temperature to 30~60℃ to obtain mixture B;

[0051] (3) Add 5% of the coal dispersant prepared in Example 2 to mixture B, and stir at high speed for 30-60 minutes to obtain an environmentally friendly liquid coal additive.

[0052] Comparative Example 1

[0053] This comparative example provides an environmentally friendly liquid coal additive, which differs from Example 4 only in that it uses polyvinyl alcohol dispersant. The specific preparation steps are as follows:

[0054] (1) Add the remaining water to the reactor by weight percentage, stir, add 10% iron oxide and 0.5% cerium nitrate to the reactor, stir until completely dissolved, and obtain mixture A;

[0055] (2) Add 0.5% calcium oxide, 0.2% ammonium bicarbonate, 4.5% potassium carbonate, 0.5% kaolin and 2% magnesium chloride to mixture A, continue stirring, and control the reaction temperature to 30~60℃ to obtain mixture B;

[0056] (3) Add 5% polyvinyl alcohol with a number average molecular weight of 500~1800 g / mol to mixture B, and stir at high speed for 30~60 minutes to obtain an environmentally friendly liquid coal additive.

[0057] Comparative Example 2

[0058] This comparative example provides an environmentally friendly liquid coal additive, which differs from Example 4 only in that it uses octadecyl alcohol polyoxyethylene ether dispersant. The specific preparation steps are as follows:

[0059] (1) Add the remaining water to the reactor by weight percentage, stir, add 10% iron oxide and 0.5% cerium nitrate to the reactor, stir until completely dissolved, and obtain mixture A;

[0060] (2) Add 0.5% calcium oxide, 0.2% ammonium bicarbonate, 4.5% potassium carbonate, 0.5% kaolin and 2% magnesium chloride to mixture A, continue stirring, and control the reaction temperature to 30~60℃ to obtain mixture B;

[0061] (3) Add 5% of octadecyl alcohol polyoxyethylene ether dispersant with a number average molecular weight of 4000~5000 g / mol to mixture B, and stir at high speed for 30~60 minutes to obtain an environmentally friendly liquid coal additive.

[0062] Comparative Example 3

[0063] This comparative example provides an environmentally friendly liquid coal additive, which differs from Example 4 only in that it uses a polycarboxylate dispersant. The specific preparation steps are as follows:

[0064] (1) Add the remaining water to the reactor by weight percentage, stir, add 10% iron oxide and 0.5% cerium nitrate to the reactor, stir until completely dissolved, and obtain mixture A;

[0065] (2) Add 0.5% calcium oxide, 0.2% ammonium bicarbonate, 4.5% potassium carbonate, 0.5% kaolin and 2% magnesium chloride to mixture A, continue stirring, and control the reaction temperature to 30~60℃ to obtain mixture B;

[0066] (3) Add 5% of polycarboxylate dispersant with a number average molecular weight of 3000~6000 g / mol to mixture B, and stir at high speed for 30~60 minutes to obtain an environmentally friendly liquid coal additive.

[0067] Combustion experiment:

[0068] In use, 10 kg of the environmentally friendly liquid coal additives prepared in Examples 3-4 and Comparative Examples 1-3 were diluted in water to make 2 tons. The diluted environmentally friendly liquid coal additives were then sprayed onto 20 tons of coal with a calorific value of 6000 Kcal / kg using a spraying device for combustion. The comparison results of the combustion of coal with additives and coal without additives are shown in Table 1.

[0069] Table 1. Comparison of combustion performance.

[0070]

[0071] As shown in Table 1, the coal dispersant of the present invention has high dispersibility and can significantly improve the combustion performance of coal by making environmentally friendly liquid coal additives.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that after reading this application specification, they can still modify or make equivalent substitutions to the specific implementation of the present invention, but these modifications or changes do not depart from the protection scope of the pending claims of the present invention.

Claims

1. A method for preparing a coal combustion dispersant, characterized in that, Includes the following steps: S1. Polyvinyl alcohol, oxetane-3-methanol, a strong base catalyst and a first solvent are mixed and reacted at a higher temperature to obtain a comb-shaped polymer; S2. Mix the comb-shaped polymer, sodium di(laurhoyl ether-7) citrate, strong acid catalyst, polymerization inhibitor, and second solvent, and heat the mixture to obtain a coal combustion dispersant. The mass ratio of polyvinyl alcohol to oxetane-3-methanol is 8:2~5; The amount of the strong base catalyst used is 2000~4000 ppm of the total reaction raw materials; The mass ratio of the comb-shaped polymer to sodium di(laurate-7) citrate is 5~10:1; The mass ratio of the comb-shaped polymer, the strong acid catalyst, and the polymerization inhibitor is 1:0.1~0.2:0.05~0.

08.

2. The method for preparing the coal dispersant as described in claim 1, characterized in that, In S1, the strong base catalyst includes one of potassium hydroxide, sodium hydroxide, potassium tert-butoxide, sodium tert-butoxide, sodium methoxide, sodium ethoxide, and sodium isopropoxide. And / or, the first solvent is selected from at least one of dichloromethane, chloroform, tetrahydrofuran, toluene, 1,1-dichloroethane, 1,2-dichloroethane, and xylene; And / or, the temperature of the heating reaction is 90~130℃, and the time is 10~20 hours.

3. The method for preparing the coal dispersant as described in claim 1, characterized in that, In S2, the strong acid catalyst is selected from at least one of sulfuric acid, phosphoric acid, p-toluenesulfonic acid, and methanesulfonic acid.

4. The method for preparing the coal dispersant as described in claim 1, characterized in that, In S2, the polymerization inhibitor is selected from at least one of hydroquinone, methyl hydroquinone, tert-butylhydroquinone, and 2,6-di-tert-butylhydroquinone; And / or, the second solvent is selected from at least one of dichloromethane, chloroform, tetrahydrofuran, toluene, 1,1-dichloroethane, 1,2-dichloroethane, and xylene; And / or, the heating reaction is carried out by heating to 100~130℃ and reacting for 3~6 hours.

5. A coal combustion dispersant, characterized in that, The coal dispersant is prepared by the method for preparing the coal dispersant according to any one of claims 1 to 4.

6. An environmentally friendly liquid coal additive, characterized in that, Includes the coal dispersant as described in claim 5.

7. The environmentally friendly liquid coal additive as described in claim 6, characterized in that, The amount of the coal dispersant used, by weight percentage, is 5-8% of that used in environmentally friendly liquid coal additives.

8. The environmentally friendly liquid coal additive as described in claim 7, characterized in that, The environmentally friendly liquid coal additive also includes the following raw materials in the following mass fractions: 4-10% iron oxide, 0.5-2% cerium nitrate, 0.1-0.5% calcium oxide, 0.2-0.5% ammonium bicarbonate, 2.5-4.5% potassium carbonate, 0.5-2.5% kaolin, 0.5-2% magnesium chloride, and the balance being water.

9. A method for preparing an environmentally friendly liquid coal additive as described in claim 8, characterized in that, Includes the following steps: (1) Add the remaining water to the reaction vessel and stir. Add 4-10% iron oxide and 0.5-2% cerium nitrate to the reaction vessel and stir until completely dissolved to obtain mixture A; (2) Add 0.1-0.5% calcium oxide, 0.2-0.5% ammonium bicarbonate, 2.5-4.5% potassium carbonate, 0.5-2.5% kaolin and 0.5-2% magnesium chloride to mixture A, continue stirring, and control the reaction temperature to 30-60℃ to obtain mixture B; (3) Add 5-8% of the coal dispersant as described in claim 5 to mixture B, and stir at high speed for 30-60 minutes to obtain an environmentally friendly liquid coal additive.

10. A modified coal comprising the environmentally friendly liquid coal additive and coal as described in any one of claims 6 to 8.

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