A weathered coal-based sodium / potassium humate desulfurization coal catalyst and its preparation

Abstract

This invention discloses a method for preparing an environmentally friendly and readily available catalyst with sulfur-fixing and coal-saving effects. The method is characterized by weathered coal, humic acid, metal oxides, and a leavening agent; wherein 15-30 parts of sodium humate, 25-35 parts of potassium humate, 15-25 parts of calcium oxide, 10-20 parts of magnesium oxide, 5-15 parts of sodium bicarbonate, and 3-12 parts of sodium chloride are used to obtain the sulfur-fixing and coal-saving catalyst. The metal oxides in this catalyst can effectively remove SO2 generated during coal combustion, and the leavening agent increases the contact between coal and air and humic acid salts, thus exhibiting a significant sulfur-fixing effect and improving coal combustion efficiency.

Description

Technical Field

[0001] This invention relates to the preparation of an inexpensive, readily available, sulfur-fixing, and coal-saving catalyst, and particularly to the preparation of a weathered coal-based sodium / potassium humate sulfur-fixing coal combustion catalyst. Background Technology

[0002] Given my country's basic national condition of "abundant coal, scarce oil, and limited gas," coal is a crucial component of my country's energy structure. my country's coal is mainly distributed in Shanxi, Shaanxi, Inner Mongolia, and Xinjiang, with Xinjiang possessing the largest coal resources in the country. However, coal combustion is accompanied by problems such as SO2 emissions and low combustion efficiency. To address these issues, desulfurization additives and combustion catalysts are typically added to coal. Currently, calcium oxide is commonly used for desulfurization, but the desulfurization product, calcium sulfate, precipitates and coats the coal surface, affecting combustion. While inorganic metals can improve coal combustion efficiency, the improvement is limited. Based on the above problems and the abundance of weathered coal in Xinjiang, this application provides a desulfurization and coal-saving catalyst, and further provides a preparation method. Summary of the Invention

[0003] The purpose of this invention is to develop a method for preparing an environmentally friendly, readily available, sulfur-fixing, and coal-saving catalyst.

[0004] The objective of this invention is achieved through the following technical solutions.

[0005] A method for preparing an environmentally friendly, readily available, sulfur-fixing, and coal-saving catalyst, characterized by the following process steps: (1) Preparation of potassium humate: First, the weathered coal was crushed and sieved (80-100 mesh). 5 g of weathered coal was added to 30 mL of aqueous solution containing 0.45 g of potassium hydroxide. After stirring magnetically for 1 h at room temperature, the potassium humate solution was collected by filtration. The pH was adjusted to 2-3 with HCl, and solid humic acid was precipitated. The filtrate was washed with water until the pH was 5-6, and the solid was dried to obtain potassium-containing humic acid.

[0006] (2) Extraction of sodium humate: First, the weathered coal is crushed and sieved (80-100 mesh). 5 g of weathered coal is mixed with 50 mL of 1% sodium hydroxide aqueous solution and stirred for 2 h to generate sodium humate solution. The pH is adjusted to 2-3 with HCl, and solid humic acid is precipitated. After washing the filtrate with water to a pH of 5-6, the solid is dried to obtain sodium-containing humic acid.

[0007] (3) An environmentally friendly, readily available, sulfur-fixing, and coal-saving catalyst: Add to the reaction vessel The following components are used: 20-40 parts (preferably 22-30 parts) of weathered coal-based sodium humate, 10-30 parts (preferably 15-25 parts) of weathered coal-based potassium humate, 10-30 parts (preferably 15-25 parts) of calcium oxide, 5-20 parts (preferably 10-15 parts) of magnesium oxide, 10-20 parts (preferably 12-18 parts) of sodium bicarbonate, and 5-25 parts (preferably 8-15 parts) of sodium chloride. When mixed evenly, this produces an environmentally friendly, readily available, sulfur-fixing, and coal-saving catalyst. Adding this catalyst at a ratio of 0.01% of the raw coal mass reduces sulfur emissions from coal combustion, resulting in significant environmental benefits. It also significantly improves combustion efficiency, saving 22%-35% of coal and achieving a sulfur-fixing efficiency of 35-60%.

[0008] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) Xinjiang has abundant weathered coal. The present invention extracts humic acid salts from weathered coal, which has the advantages of wide availability and easy access. (2) The active groups (such as carboxyl groups, phenolic hydroxyl groups, etc.) in sodium humate can interact with the organic components in coal to improve combustion efficiency; (3) The metal ions (sodium, potassium) in the additives can lower the ignition temperature of coal and promote more complete combustion; (4) Sodium / potassium humate can form pores during combustion, increasing the specific surface area of ​​coal and improving combustion efficiency; (4) The leavening agent effectively inhibits the precipitation and agglomeration of calcium sulfate on the coal surface during combustion, increases the contact area between coal and air, and further improves the coal-saving effect; (5) Adding sodium humate, potassium humate, sodium chloride, potassium chloride and sodium bicarbonate within the optimal ratio range has a synergistic effect on combustion efficiency, which is significantly better than single components and other coal-saving and sulfur-fixing products. (6) The inorganic salts used in this invention are inexpensive and readily available. They are added in appropriate proportions with organic humic acid salts to achieve the goal of low cost and high profit. (7) Traditional calcium-based sulfur fixatives are prone to sintering at high temperatures, which affects combustion and sulfur fixation efficiency. Using humate salts for sulfur fixation can solve this problem. Detailed Implementation

[0009] The following examples illustrate the preparation of potassium humate: First, Xinjiang weathered coal was pulverized and sieved (80-100 mesh). 5 g of weathered coal was added to 30 mL of an aqueous solution containing 0.45 g of potassium hydroxide. The mixture was magnetically stirred at room temperature for 1 h, and then the potassium humate solution was collected by filtration. The pH was adjusted to 2-3 (2.6 in this case) with 36% HCl, precipitating solid potassium humate. The filtrate was washed with water until the pH was adjusted to 5-6 (5.7 in this case). The solid was then dried to obtain potassium humate containing potassium, with a yield of 75%, of which the potassium content exceeded 17%.

[0010] The extraction of sodium humate used in the following examples is as follows: First, Xinjiang weathered coal was pulverized and sieved (80-100 mesh). 5g of weathered coal was mixed with 50mL of a 1% sodium hydroxide aqueous solution and stirred for 2 hours to generate a sodium humate solution. The pH was adjusted to 2-3 (2.4 in this case) with 36% HCl, and solid sodium humate was precipitated. The filtrate was washed with water until the pH was 5-6 (5.5 in this case), and the solid was dried to obtain sodium humate containing sodium, with a yield of 78%, of which the sodium content exceeded 10%.

[0011] The aforementioned weathered coal originated from Xinjiang, and its humic acid content was 50-70% (67.3% in this case). Example 1 Coal-saving catalyst: 40 parts of weathered coal-based sodium humate, 10 parts of weathered coal-based potassium humate, 15 parts of calcium oxide, 10 parts of magnesium oxide, 15 parts of sodium bicarbonate, and 5 parts of sodium chloride are mixed evenly to obtain a sulfur-fixing and coal-saving catalyst.

[0012] Example 2 Coal-saving catalyst: 40 parts of weathered coal-based sodium humate, 10 parts of weathered coal-based potassium humate, 15 parts of calcium oxide, 5 parts of magnesium oxide, 15 parts of sodium bicarbonate, and 15 parts of sodium chloride are mixed evenly to obtain a sulfur-fixing and coal-saving catalyst.

[0013] Example 3 Coal-saving catalyst: 40 parts of weathered coal-based sodium humate, 10 parts of weathered coal-based potassium humate, 20 parts of calcium oxide, 15 parts of magnesium oxide, 10 parts of sodium bicarbonate, and 5 parts of sodium chloride are mixed evenly to obtain a sulfur-fixing and coal-saving catalyst.

[0014] Example 4 Coal-saving catalyst: 40 parts of weathered coal-based sodium humate, 10 parts of weathered coal-based potassium humate, 15 parts of calcium oxide, 10 parts of magnesium oxide, 15 parts of sodium bicarbonate, and 5 parts of sodium chloride are mixed evenly to obtain a sulfur-fixing and coal-saving catalyst.

[0015] Example 5 Coal-saving catalyst: 30 parts of weathered coal-based sodium humate, 10 parts of weathered coal-based potassium humate, 15 parts of calcium oxide, 15 parts of magnesium oxide, 15 parts of sodium bicarbonate, and 15 parts of sodium chloride are mixed evenly to obtain a sulfur-fixing and coal-saving catalyst.

[0016] Example 6 Coal-saving catalyst: 30 parts of weathered coal-based sodium humate, 10 parts of weathered coal-based potassium humate, 15 parts of calcium oxide, 15 parts of magnesium oxide, 15 parts of sodium bicarbonate, and 15 parts of sodium chloride are mixed evenly to obtain a sulfur-fixing and coal-saving catalyst.

[0017] Example 7 Coal-saving catalyst: 25 parts of weathered coal-based sodium humate, 15 parts of weathered coal-based potassium humate, 15 parts of calcium oxide, 10 parts of magnesium oxide, 15 parts of sodium bicarbonate, and 15 parts of sodium chloride are mixed evenly to obtain a sulfur-fixing and coal-saving catalyst.

[0018] Example 8 Coal-saving catalyst: 20 parts of weathered coal-based sodium humate, 10 parts of weathered coal-based potassium humate, 25 parts of calcium oxide, 15 parts of magnesium oxide, 15 parts of sodium bicarbonate, and 15 parts of sodium chloride are mixed evenly to obtain a sulfur-fixing and coal-saving catalyst.

[0019] Example 9 Coal-saving catalyst: 25 parts of weathered coal-based sodium humate, 25 parts of weathered coal-based potassium humate, 15 parts of calcium oxide, 10 parts of magnesium oxide, 15 parts of sodium bicarbonate, and 10 parts of sodium chloride are mixed evenly to obtain a sulfur-fixing and coal-saving catalyst.

[0020] Example 10 Coal-saving catalyst: 20 parts of weathered coal-based sodium humate, 15 parts of weathered coal-based potassium humate, 15 parts of calcium oxide, 10 parts of magnesium oxide, 15 parts of sodium bicarbonate, and 25 parts of sodium chloride are mixed evenly to obtain a sulfur-fixing and coal-saving catalyst.

[0021] Example 11 Coal-saving catalyst: 20 parts of weathered coal-based sodium humate, 15 parts of weathered coal-based potassium humate, 25 parts of calcium oxide, 15 parts of magnesium oxide, 15 parts of sodium bicarbonate, and 10 parts of sodium chloride are mixed evenly to obtain a sulfur-fixing and coal-saving catalyst.

[0022] Example 12 Coal-saving catalyst: 25 parts of weathered coal-based sodium humate, 25 parts of weathered coal-based potassium humate, 15 parts of calcium oxide, 10 parts of magnesium oxide, 23 parts of sodium bicarbonate, and 7 parts of sodium chloride are mixed evenly to obtain a sulfur-fixing and coal-saving catalyst.

[0023] Example 13 Coal-saving catalyst: 25 parts of weathered coal-based sodium humate, 25 parts of weathered coal-based potassium humate, 35 parts of calcium oxide, 3 parts of magnesium oxide, 5 parts of sodium bicarbonate, and 7 parts of sodium chloride are mixed evenly to obtain a sulfur-fixing and coal-saving catalyst.

[0024] Example 14 Coal-saving catalyst: 45 parts of weathered coal-based sodium humate, 5 parts of weathered coal-based potassium humate, 15 parts of calcium oxide, 10 parts of magnesium oxide, 15 parts of sodium bicarbonate, and 10 parts of sodium chloride are mixed evenly to obtain a sulfur-fixing and coal-saving catalyst.

[0025] Comparative Example 1 The specific implementation process and conditions of this comparative example are the same as those of Example 9, except that calcium oxide, magnesium oxide, sodium bicarbonate, and sodium chloride are not added.

[0026] Comparative Example 2 The specific implementation process and conditions of this comparative example are the same as those of Example 9, except that calcium oxide and magnesium oxide are not added.

[0027] Comparative Example 3 The specific implementation process and conditions of this comparative example are the same as those of Example 9, except that sodium bicarbonate and sodium chloride are not added.

[0028] Comparative Example 4 The specific implementation process and conditions of this comparative example are the same as those of Example 9, except that calcium oxide is not added.

[0029] Comparative Example 5 The specific implementation process and conditions of this comparative example are the same as those of Example 9, except that magnesium oxide is not added.

[0030] Comparative Example 6 The specific implementation process and conditions of this comparative example are the same as those of Example 9, except that sodium bicarbonate is not added.

[0031] Comparative Example 7 The specific implementation process and conditions of this comparative example are the same as those of Example 9, except that sodium chloride is not added.

[0032] Performance Evaluation The weathered coal-based sodium / potassium humate coal-fired catalysts prepared in Examples 1-11 were mixed with pulverized coal at a ratio of 1:0.1% and tested. Coal samples without additives served as blank controls. The coal saving rate and sulfide emission reduction efficiency (calculated as sulfur dioxide and sulfur trioxide) were measured. The coal saving rate was calculated as (R2-R1) / R2. R1: grate speed when the catalyst was added for stable heating; R2: grate speed of the blank sample when the catalyst was added for stable heating.

[0033] The national standard for testing the sulfur content of coal during combustion in a boiler is GB / T 214-2007, "Determination of Total Sulfur in Coal". The high-temperature combustion neutralization method is used, and the specific operation is as follows: The coal sample was burned in a high-temperature oxygen stream, converting the sulfur in the coal into sulfur dioxide and sulfur trioxide. The sulfur dioxide was then absorbed by hydrogen peroxide solution, and the resulting sulfuric acid was neutralized and titrated with a standard sodium hydroxide solution. The mass content of total sulfur emitted in the coal was calculated based on the amount of standard sodium hydroxide solution consumed.

[0034] A coal sample (100 g of coal powder and 1 g of catalyst were weighed, stirred evenly, and allowed to stand for 12 h to obtain the coal sample. The sample without coal-saving agent was used as a blank control) was burned in an oxygen stream at 1200℃ and kept constant at 1200℃±5℃ to convert the sulfur in the coal into sulfur dioxide and sulfur trioxide. The sulfur dioxide was then absorbed by hydrogen peroxide solution, and the generated sulfuric acid was neutralized and titrated with a standard sodium hydroxide solution. The mass content of total sulfur emitted in the coal was calculated based on the amount of standard sodium hydroxide solution consumed.

[0035] The results show that the weathered coal-based sodium / potassium humate desulfurization coal combustion catalysts prepared in Examples 1-11 can significantly improve the combustion efficiency and sulfur emissions of coal compared with the blank sample, and the effect is better than the catalysts in Comparative Examples 1-3.

[0036]

[0037]

[0038] As can be seen from Examples 1-11 and Comparative Examples 1-3, the weathered coal-based sodium / potassium humate desulfurization coal combustion catalyst and its preparation method provided by the present invention have good effects in promoting coal combustion, reducing combustion time, improving combustion efficiency, and reducing pollutant emissions, and have broad development prospects.

[0039] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A weathered coal-based sodium / potassium humate desulfurization and coal-saving catalyst, characterized in that, Includes the following components: 20-40 parts (preferably 22-30 parts) of weathered coal-based sodium humate, 10-30 parts (preferably 15-25 parts) of weathered coal-based potassium humate, 10-30 parts (preferably 15-25 parts) of calcium oxide, 5-20 parts (preferably 10-15 parts) of magnesium oxide, 10-20 parts (preferably 12-18 parts) of sodium bicarbonate, and 5-25 parts (preferably 8-15 parts) of sodium chloride.

2. The catalyst according to claim 1, characterized in that, The preparation process of weathered coal-based sodium humate is as follows: First, the weathered coal is crushed and sieved (80-100 mesh). 5 g of weathered coal is mixed with 30-80 mL of sodium hydroxide aqueous solution with a mass concentration of 0.5-2% and stirred for 1-4 h. The solid and liquid are separated and the solution is collected. The pH is adjusted to 2-3 with HCl with a mass concentration of 20-36% to precipitate sodium humate. The filtrate is washed with water until the pH is 5-6, and the solid is dried. After drying, sodium humate with a sodium mass content of 8-12% is obtained.

3. The catalyst according to claim 1, characterized in that, The preparation process of weathered coal-based potassium humate is as follows: First, the weathered coal is crushed and sieved (80-100 mesh). 5 g of weathered coal is added to 20-40 mL of an aqueous solution containing 0.4-0.5 g of potassium hydroxide. After stirring at room temperature for 0.5-2 h, the solution is collected after solid-liquid separation. The pH is adjusted to 2-3 with HCl (20-36% by mass) to precipitate potassium humate. The filtrate is washed with water until the pH is 5-6, and then the solid is dried to obtain potassium humate with a potassium content of 15-19% by mass.

4. The catalyst according to claim 1, characterized in that, The catalyst is prepared by grinding and mixing calcium oxide, magnesium oxide, sodium bicarbonate, and sodium chloride.

5. The catalyst according to claim 1, characterized in that, The optimal mass ratio of humates (weathered coal-based sodium humate and weathered coal-based potassium humate) to inorganic metal salts (calcium oxide and magnesium oxide, sodium bicarbonate and sodium chloride) is 1:

1.

6. The catalyst according to claim 1, characterized in that, The pH value is 7-8.

7. A method for preparing the catalyst according to any one of claims 1-5, characterized in that, The materials required for any of the catalysts described in claims 1-5 can be directly mixed.

8. The application of any one of the catalysts described in claims 1-5 in the combustion of desulfurized coal.

9. The application according to claim 7, characterized in that, Add 0.1-0.2g of weathered coal-based sodium / potassium humate desulfurization and coal-saving catalyst to every 100g of raw coal.

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