Process for separating and dewatering power coal briquettes

Abstract

This invention proposes a process for separating and dewatering lump coal, belonging to the field of coal washing technology. A plasma reactor is used to ionize and activate flocculant solution 1 to form flocculant solution 2. The ionized and activated flocculant solution 2 is then sprayed onto the lump coal using a venturi tube. Subsequently, a plasma spray gun is used to emit plasma onto the lump coal sprayed with flocculant solution 2, thereby modifying the surface of the coal lump coated with flocculant solution 2 to form a solidified hydrophobic film. The lump coal with the solidified hydrophobic film is then separated to separate gangue from the lump coal, obtaining the final product. This effectively improves the hydrophobicity and brittleness of the lump coal, ultimately improving the dewatering effect of the lump coal.

Description

Technical Field

[0001] This invention belongs to the field of coal washing and beneficiation technology, specifically relating to a process for separating and dewatering power coal lumps. Background Technology

[0002] Thermal coal accounts for over 80% of my country's total coal production. Larger coal particles have lower water-holding capacity, and lump coal typically has a much lower moisture content than fine coal. Therefore, further dehydration of lump coal has received less attention. However, with increasingly stringent quality requirements for thermal coal and its shift towards raw material utilization, the requirements for product moisture content are becoming more stringent. When using water-based or heavy-medium methods to process lump coal, the high water-holding capacity and low strength of low-rank coal lead to the adsorption of a large amount of water on the surface during washing and beneficiation. This can also cause pulverization, reducing the yield of clean lump coal and further increasing the product moisture content. Existing lump coal dewatering processes generally involve dewatering after the lump coal has passed through the sorting stage. However, lump coal is dry and has very low moisture content before entering the sorting stage. Since thermal coal has many hydrophilic groups on its surface, the adsorbed water is difficult to remove after passing through the sorting stage, and water absorption easily leads to a decrease in surface strength and an increase in the pulverization rate. Currently, there is limited research on hydrophobic treatment of lump coal before entering the sorting stage to prevent pulverization during the sorting and dewatering processes.

[0003] Existing technologies dehydrate lump coal after it changes from a dry to a wet state, which makes moisture removal difficult. The lump coal has a high crushing rate, and fine particles are prone to agglomeration or settling on coarse particles, increasing the specific surface area and making dehydration more difficult. Summary of the Invention

[0004] To address the shortcomings of existing technologies, a process for separating and dewatering lump coal is provided. This process utilizes a plasma spray gun to perform plasma surface coating modification on dry lump coal, thereby improving its hydrophobicity, shatter resistance, and looseness, and enhancing the dewatering effect of lump coal.

[0005] To achieve the above-mentioned technical objectives, this invention discloses a process for separating and dewatering coal lumps. A plasma reactor is used to ionize and activate flocculant solution 1, which is then modified to become flocculant solution 2. The ionized and activated flocculant solution 2 is sprayed onto the surface of the coal lumps using a venturi tube. The modified flocculant solution 2 provides better coverage and uniformity on the coal surface. Plasma gas is then emitted onto the coal lumps sprayed with flocculant solution 2 using a plasma spray gun. Utilizing the etching and chemical evaporation effects of the plasma spray gun, the surface of the coal lumps sprayed with flocculant solution 2 is modified to form a solidified hydrophobic film. The coal lumps with the solidified hydrophobic film are then subjected to re-selection, thereby separating gangue from the coal lumps to obtain the final product.

[0006] The specific steps are as follows:

[0007] Firstly, the flocculant solution 1 is ionized and activated using a plasma reactor;

[0008] Then, the flocculant solution 2 that has been electrically activated is fed into the venturi tube, and high-pressure air is supplied into the venturi tube at the same time, so that the flocculant solution 2 forms an active oil-gas mixture and is sprayed onto the coal block 1 that continues to turn on the roller screen. As the roller screen works, all the coal blocks 1 are evenly covered with a layer of activated flocculant solution 2 and air mixture, forming coal block 2.

[0009] Afterwards, the coal block 2 that continues to tumble on the roller screen is treated with a plasma spray gun. Through the etching effect and chemical evaporation effect of the plasma spray gun, the surface of the coal block 2 sprayed with flocculant solution 2 is modified to form a solidified hydrophobic film layer, which constitutes coal block 3. Coal block 3 has good hydrophobicity.

[0010] Finally, the coal lump 3 is subjected to gravity separation using a sorting device to separate the gangue. The clean coal product is then fed into a dewatering screen for dewatering, thereby obtaining the final dewatered clean coal.

[0011] Furthermore, the sieve opening of the roller screen is 3mm-6mm.

[0012] Furthermore, the sorting equipment is a heavy medium sorting device.

[0013] Furthermore, the flocculant solution is a product obtained by diluting flocculant with water. The flocculant is a polyacrylamide-based product, and the concentration of the flocculant solution is 10%-20%.

[0014] Furthermore, a blower is used to supply high-pressure air into the venturi tube.

[0015] Furthermore, the plasma spray gun has a working power of 1kW-2kW and a current of 2A-3A, and adopts the form of electric arc plasma.

[0016] A dewatering system for briquette coal includes a roller screen for turning over briquette coal placed on top. The roller screen is equipped with a Venturi tube for spraying flocculant solution and a plasma spray gun for forming a solidified hydrophobic film on the surface of the briquette coal. Untreated briquette coal is connected upstream of the roller screen, and a sorting device for separating the processed briquette coal is connected downstream of the roller screen. The clean coal outlet of the sorting device is connected to a dewatering screen. The feed inlet of the Venturi tube is connected to a plasma reactor for ionizing and activating the flocculant solution, and the air inlet of the Venturi tube is connected to an air compressor for conveying air.

[0017] Beneficial effects: This method allows for the spraying of plasma-modified flocculant solution onto the surface of lump coal before it enters the wet separation stage. This ensures that the flocculant solution is evenly coated on the surface of the lump coal. Then, a plasma spray gun is used to irradiate and solidify the solution, forming a stable modified flocculant film on the surface of the lump coal. This improves the hydrophobicity, crush resistance, and looseness of the lump coal, ultimately resulting in better dewatering of the lump coal. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the process for separating and dewatering power coal lumps according to the present invention;

[0019] In the diagram: A - Plasma reactor, B - Blower, C - Venturi tube, D - Roller screen, E - Plasma spray gun, F - Sorting equipment, G - Dewatering screen. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings:

[0021] like Figure 1 As shown, this invention discloses a process for separating and dewatering lumps of thermal coal, comprising the following steps:

[0022] Firstly, the flocculant solution 1 is activated by ionization using plasma reactor A;

[0023] Then, high-pressure air is supplied to the Venturi tube C by the air compressor B, and the electro-activated flocculant solution 2 is fed into the Venturi tube C. At the same time, high-pressure air is supplied to the Venturi tube C, so that the flocculant solution 2 forms an active oil-gas mixture and is sprayed onto the coal lumps 1 that continue to tumble on the roller screen D. As the roller screen D works, all the coal lumps 1 are evenly covered with a layer of activated flocculant solution 2 and air mixture, forming coal lumps 2. The flocculant solution is a product of flocculant diluted with water. The flocculant is polyacrylamide and the concentration of the flocculant solution is 10%-20%. The screen opening of the roller screen D is 3mm-6mm.

[0024] Subsequently, the coal block 2, which continues to tumble on the roller screen D, is treated with a plasma spray gun E. Through the etching effect and chemical evaporation effect of the plasma spray gun E, the surface of the coal block 2 sprayed with flocculant solution 2 is modified to form a solidified hydrophobic film layer, which constitutes coal block 3. Coal block 3 has good hydrophobicity. The working power of the plasma spray gun E is 1kw-2kw, the current is 2A-3A, and it adopts the form of electric arc plasma.

[0025] Finally, the coal lump 3 is subjected to gravity separation using the sorting equipment F to separate the gangue. The clean coal product is then fed into the dewatering screen G for dewatering, thereby obtaining the final dewatered clean coal.

[0026] The dewatering system for briquette coal includes a roller screen D for turning over the coal briquette placed above it. The roller screen D is equipped with a Venturi tube C for spraying flocculant solution and a plasma spray gun E for forming a solidified hydrophobic film on the surface of the briquette coal. Untreated briquette coal is connected upstream of the roller screen D, and a sorting device F for sorting the processed briquette coal is connected downstream of the roller screen D. The clean coal outlet of the sorting device F is connected to a dewatering screen G. The feed inlet of the Venturi tube C is connected to a plasma reactor A for ionizing and activating the flocculant solution, and the air inlet of the Venturi tube C is connected to an air compressor B for conveying air.

[0027] Example: The method described in this invention is used. Polyacrylamide flocculant is dissolved in water to prepare flocculant solution 1; flocculant solution 1 is fed into a medium-barrier plasma reactor A to become flocculant solution 2; air is pressurized by a blower B and fed into a venturi tube C; flocculant 2 is fed into the intake of venturi tube C; lump coal 1 from the coal preparation plant is fed into a roller screen D; the outlet of venturi tube C feeds into the roller screen D, where it interacts with the surface of the lump coal to become lump coal 2; lump coal 2 is treated by a plasma spray gun E positioned above the material layer to form a solidified hydrophobic film layer, becoming lump coal 3; lump coal 3 is fed into a lump coal sorting device F and separated into clean coal and gangue; the clean coal enters a dewatering screen G; the material on the dewatering screen G becomes the final product; the gangue is discharged from the system. Through the above process, the moisture content of the lump clean coal is reduced to below 10% on-site, compared to... Figure 1 The process reduces the moisture content of lump coal by more than 2%, increases the calorific value by more than 100 kcal / kg, and reduces the -13mm particle size increment by less than 5%, with the -3mm content reduced to less than 5%. This is the existing lump coal dewatering process in power coal preparation plants. The lump coal is fed into a linear dewatering screen B1 through a shallow heavy medium trough A1, and becomes the product directly after dewatering. The moisture content of the lump coal is around 12%, the -13mm particle size increment is more than 10%, and the -3mm particle size content is around 10%.

Claims

1. A process for the separation and dewatering of power coal lumps, characterized in that: A dewatering system for briquette coal is characterized by comprising: a roller screen (D) for turning over the coal briquette placed above; a venturi tube (C) for spraying flocculant solution and a plasma spray gun (E) for forming a solidified hydrophobic film on the surface of the briquette coal; untreated briquette coal is connected upstream of the roller screen (D); a sorting device (F) for sorting the processed briquette coal is connected downstream of the roller screen (D); a dewatering screen (G) is connected to the clean coal outlet of the sorting device (F); a plasma reactor (A) for ionizing and activating the flocculant solution is connected to the feed inlet of the venturi tube (C); and an air compressor (B) for conveying air is connected to the air inlet of the venturi tube (C). The flocculant solution 1 is ionized and activated using a plasma reactor (A) to become flocculant solution 2. The ionized and activated flocculant solution 2 is then sprayed onto the surface of the lump coal using a venturi tube (C). The modified flocculant solution 2 has a better coverage and uniformity on the surface of the lump coal. Plasma gas is then emitted onto the lump coal sprayed with flocculant solution 2 using a plasma spray gun (E). The etching effect and chemical evaporation effect of the plasma spray gun (E) are used to modify the surface of the coal lump sprayed with flocculant solution 2 to form a solidified hydrophobic film. The coal lump with the solidified hydrophobic film is then reselected to separate the gangue from the lump coal and obtain the final product.

2. The process for power briquette coal separation and dewatering according to claim 1, characterized in that, The specific steps are as follows: Firstly, the flocculant solution 1 is ionized and activated using a plasma reactor (A); Then, the flocculant solution 2 that has been electrically activated is fed into the venturi tube (C), and high-pressure air is supplied to the venturi tube (C) at the same time, so that the flocculant solution 2 forms an active oil-gas mixture and is sprayed onto the coal block 1 that continues to turn on the roller screen (D). As the roller screen (D) works, all the coal blocks 1 are evenly covered with a layer of activated flocculant solution 2 and air mixture, forming coal block 2. Afterwards, the coal block 2 that continues to tumble on the roller screen (D) is treated with a plasma spray gun (E). Through the etching effect and chemical evaporation effect of the plasma spray gun (E), the surface of the coal block 2 sprayed with flocculant solution 2 is modified to form a solidified hydrophobic film layer, which constitutes coal block 3. Coal block 3 has good hydrophobicity. Finally, the coal block 3 is subjected to gravity separation using a sorting device (F) to separate the gangue, and the clean coal product is fed into a dewatering screen (G) for dewatering, thereby obtaining the final dewatered clean coal.

3. The process for power briquette coal separation and dewatering according to claim 2, characterized in that, The sieve opening of the roller screen (D) is 3mm-6mm.

4. The process for sorting and dewatering of power coal briquettes according to claim 2, characterized in that, The sorting equipment is a heavy medium sorting device.

5. The process for power briquette coal separation and dewatering according to claim 2, characterized in that, The flocculant solution is a product obtained by diluting flocculant with water. The flocculant is polyacrylamide and the concentration of the flocculant solution is 10%-20%.

6. The process for power briquette coal separation and dewatering according to claim 2, characterized in that, High-pressure air is supplied to the venturi tube (C) using an air compressor (B).

7. The process for power briquette coal separation and dewatering according to claim 2, characterized in that, The plasma spray gun (E) has a working power of 1kW-2kW and a current of 2A-3A, and uses electric arc plasma.

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