Power coal lump coal separation and dehydration process

Abstract

The invention provides a lump coal separation and dehydration process for power coal, and belongs to the technical field of coal washing. The method comprises the following steps: performing ionization activation on a flocculating agent solution 1 by using a plasma reactor to form a flocculating agent solution 2, spraying the ionized and activated flocculating agent solution 2 to lump coal by using a Venturi tube, and then emitting plasmas to the lump coal sprayed with the flocculating agent solution 2 by using a plasma spray gun, the flocculant solution 2 is sprayed on the surface of the coal briquette, so that the surface of the coal briquette sprayed with the flocculant solution 2 is modified to form a solidified hydrophobic membrane layer, then the lump coal on which the solidified hydrophobic membrane layer is formed is sorted, and the gangue is separated from the fast coal to obtain a final product. The hydrophobicity and crushing resistance of the lump coal are effectively improved, and the dewatering effect of the lump clean coal is finally improved.

Description

Technical Field

[0001] The invention belongs to the technical field of coal washing, and in particular relates to a process for separating and dehydrating thermal coal lumps. Background Art

[0002] Thermal coal accounts for more than 80% of my country's total coal production. The larger the coal particles, the weaker their water holding capacity. Under normal circumstances, the moisture content of lump coal is much lower than that of products such as fine coal. Therefore, there is less attention paid to the further dehydration of lump coal products, but with the further improvement of thermal coal quality requirements and the shift to raw material utilization, the requirements for product moisture content have become more stringent. In the process of using water medium or heavy medium method to treat thermal coal lumps, due to the strong water holding capacity and low strength of low-rank coal, a large amount of water will be adsorbed on the surface of thermal coal during the washing process, and crushing may occur at the same time, reducing the yield of lump clean coal and further increasing the moisture content of the product. The existing lump clean dehydration process basically dehydrates the lump coal after it passes through the sorting stage, while the lump coal is in a dry state before entering the sorting stage, and the moisture content is very low. There are many hydrophilic groups on the surface of thermal coal, so once it passes through the sorting stage, the moisture adsorbed on the surface will be difficult to remove, and water absorption is likely to lead to a decrease in surface strength and an increase in crushing rate. At present, there are few studies on hydrophobic treatment of lump coal before it enters the sorting stage and preventing crushing in the sorting and dehydration stages.

[0003] The existing technology dehydrates the lump coal after it changes from dry to wet state. It is difficult to remove moisture, the lump coal has a high crushing rate, and fine particles are prone to agglomeration or sitting on coarse particles, increasing the specific surface area, making dehydration more difficult. Summary of the invention

[0004] In view of the shortcomings of the existing technology, a process for separating and dehydrating thermal coal lumps is provided, which uses a plasma spray gun to perform plasma surface coating modification on the dry lumps of coal to improve their hydrophobicity, breakage resistance and looseness, thereby improving the dehydration effect of the lumps of coal.

[0005] In order to achieve the above technical objectives, the present invention discloses a process for sorting and dehydrating thermal coal lumps, wherein a plasma reactor is used to ionize and activate a flocculant solution 1, and the flocculant solution 2 is modified to form a flocculant solution 2; a venturi tube is used to spray the ionized and activated flocculant solution 2 on the surface of the lump coal; the modified flocculant solution 2 has better coverage and uniformity on the surface of the lump coal, and a plasma spray gun is used to emit plasma gas to the lump coal sprayed with the flocculant solution 2, and the etching effect and chemical evaporation effect of the plasma spray gun are used to modify the surface of the coal lump sprayed with the flocculant solution 2 to form a solidified hydrophobic film layer, and then the coal lump formed with the solidified hydrophobic film layer is re-selected, so as to separate the gangue from the fast coal to obtain the final product.

[0006] The specific steps are as follows: First, the flocculant solution 1 is ionized and activated by using a plasma reactor; Then, the flocculant solution 2 that has been electrically activated is fed into the venturi tube, and high-pressure air is provided into the venturi tube at the same time, so that the flocculant solution 2 forms an active oil-gas mixture and is sprayed on the coal blocks 1 that continue to turn on the roller screen. As the roller screen works, all the coal blocks 1 are evenly covered with a layer of the mixture of the activated flocculant solution 2 and air to form coal blocks 2; Afterwards, the coal block 2 that continues to turn over 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 the flocculant solution 2 is modified to form a solidified hydrophobic film layer to form a coal block 3, and the coal block 3 has good hydrophobicity; Finally, the coal block 3 is re-selected by using a sorting device to separate the gangue, and the clean coal product is fed into a dewatering screen for dehydration, thereby obtaining the final dehydrated clean coal.

[0007] Furthermore, the screen gap of the roller screen is 3mm-6mm.

[0008] Furthermore, the separation equipment is a heavy medium separation device. ; Furthermore, the flocculant solution is a product obtained by diluting the flocculant with water, the flocculant is polyacrylamide, and the concentration of the flocculant solution is 10%-20%.

[0009] Furthermore, a blower is used to provide high-pressure air to the venturi tube.

[0010] Furthermore, the plasma spray gun has an operating power of 1kw-2kw, a current of 2A-3A, and adopts an arc plasma form.

[0011] A thermal coal lump dehydration system comprises a roller screen for turning over coal blocks placed on top, a venturi tube for spraying a flocculant solution and a plasma spray gun for forming a solidified hydrophobic film layer on the surface of the fast coal are respectively provided on the roller screen, untreated lump coal is connected to the upstream of the roller screen, a sorting device for sorting treated lump coal is connected to the downstream of the roller screen, and a dehydration screen is connected to the clean coal outlet of the sorting device; a plasma reactor for ionizing and activating the flocculant solution is connected to the feed port of the venturi tube, and an air compressor for conveying air is connected to the air inlet of the venturi tube.

[0012] Beneficial effects: This method can be used to spray plasma-modified flocculant solution on the thermal coal lump before it enters the wet sorting stage, so that the surface of the lump coal is evenly coated with the flocculant solution, and then use a plasma spray gun to irradiate and solidify to form a stable modified flocculant film layer on the surface of the lump coal, thereby improving the hydrophobicity, breakage resistance and looseness of the lump coal, and ultimately achieving a dehydration effect on the lump clean coal. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1It is a schematic diagram of the process flow of the thermal coal lump separation and dehydration process of the present invention; In the figure: A-plasma reactor, B-air compressor, C-Venturi tube, D-roller screen, E-plasma spray gun, F-sorting equipment, G-dewatering screen. DETAILED DESCRIPTION

[0014] The present invention will be further described below in conjunction with the accompanying drawings: like Figure 1 As shown, the present invention discloses a process for separating and dehydrating thermal coal lumps, comprising the following steps: First, the flocculant solution 1 is ionized and activated by using a plasma reactor A; Then, the air compressor B is used to provide high-pressure air to the venturi tube C, and the flocculant solution 2 that has been electrically activated is fed into the venturi tube C. At the same time, high-pressure air is provided to the venturi tube C, so that the flocculant solution 2 forms an active oil-gas mixture and is sprayed on the coal blocks 1 that continue 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 the mixture of the activated flocculant solution 2 and air to form coal blocks 2; wherein, the flocculant solution is a product obtained by diluting the flocculant with water, the flocculant is polyacrylamide, and the concentration of the flocculant solution is: 10%-20%; the screen gap of the roller screen D is 3mm-6mm; Afterwards, the coal block 2 that continues to turn 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 the flocculant solution 2 is modified to form a solidified hydrophobic film layer to constitute the coal block 3. The 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 arc plasma.

[0015] Finally, the coal block 3 is re-selected by using the sorting equipment F to separate the gangue, and the clean coal product is fed to the dewatering screen G for dehydration, so as to obtain the final dehydrated clean coal.

[0016] A thermal coal lump dehydration system comprises a roller screen D for turning over coal blocks placed on the upper side, a venturi tube C for spraying a flocculant solution and a plasma spray gun E for forming a solidified hydrophobic film layer on the surface of the fast coal are respectively provided on the roller screen D, untreated lump coal is connected to the upstream of the roller screen D, a sorting device F for sorting treated lump coal is connected to the downstream of the roller screen D, and a dehydration screen G is connected to the clean coal outlet of the sorting device F; the feed port 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.

[0017] Embodiment: The method described in the present invention is adopted. The polyacrylamide flocculant is dissolved in water to prepare a flocculant solution 1; the flocculant solution 1 is fed into a medium barrier plasma reactor A to become a flocculant solution 2; the air is pressurized by an air compressor B and then fed into a venturi tube C; the flocculant 2 is fed into a venturi tube C to inhale air; a lump of coal 1 from a coal preparation plant enters a roller screen D; the outlet of the venturi pipe C is fed into the roller screen D to react with the surface of the lump of coal to become a lump of coal 2; the lump of coal 2 is treated by a plasma spray gun E arranged above the material layer to form a solidified hydrophobic film layer to become a lump of coal 3; the lump of coal 3 is fed into a lump coal sorting equipment F to be separated into clean coal and gangue; the clean coal enters a dewatering screen G; the dewatering screen G screen becomes the final product; the gangue is discharged from the system. Through the above process, the moisture content of the on-site clean coal is reduced to less than 10%, compared with Figure 1 The moisture content of the lump clean coal is reduced by more than 2%, the calorific value is increased by about 100kcal / kg, and the -13mm increment is reduced by less than 5%, and the -3mm content is reduced to less than 5%. The lump coal dehydration process of the thermal coal preparation plant in the prior art. The lump coal is fed into the linear dehydration screen B1 through the heavy medium shallow trough A1, and becomes the product directly after dehydration. The moisture content of the lump clean coal is about 12%, the -13mm increment of the lump clean coal is more than 10%, and the -3mm particle size content is about 10%.

Claims

1. A process for separating and dehydrating thermal coal lumps, characterized in that: A plasma reactor (A) is used to ionize and activate the flocculant solution 1, and the modified flocculant solution 2 is formed; a venturi tube (C) is used to spray the ionized and activated flocculant solution 2 on the surface of the lump coal; the modified flocculant solution 2 has a better coverage and uniformity on the surface of the lump coal, and a plasma spray gun (E) is used to emit plasma gas to the lump coal sprayed with the flocculant solution 2, and the etching effect and chemical evaporation effect of the plasma spray gun (E) are used to modify the surface of the coal block sprayed with the flocculant solution 2 to form a solidified hydrophobic film layer, and then the coal block with the solidified hydrophobic film layer is reselected, so as to separate the gangue from the fast coal to obtain the final product.

2. The thermal coal lump separation and dehydration process according to claim 1, characterized in that: The specific steps are as follows: First, 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 simultaneously supplied to the venturi tube (C), so that the flocculant solution 2 forms an active oil-gas mixture and is sprayed onto the coal blocks 1 that continue 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 the mixture of the activated flocculant solution 2 and air, forming coal blocks 2; Afterwards, the coal block 2 that continues to turn over 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 the flocculant solution 2 is modified to form a solidified hydrophobic film layer to form a coal block 3, and the coal block 3 has good hydrophobicity; Finally, the coal block 3 is re-selected by using a sorting device (F) to separate the gangue, and the clean coal product is fed to a dewatering screen (G) for dehydration, thereby obtaining the final dehydrated clean coal.

3. The thermal coal lump separation and dehydration process according to claim 2, characterized in that: The screen gap of the roller screen (D) is 3mm-6mm.

4. A thermal coal lump separation and dehydration process according to claim 2, characterized in that: The separation equipment is a heavy medium separation device.

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

6. The thermal coal lump separation and dehydration process according to claim 2, characterized in that: A blower (B) is used to supply high pressure air to the venturi tube (C).

7. The thermal coal lump separation and dehydration process according to claim 2, characterized in that: The working power of the plasma spray gun (E) is 1kw-2kw, the current is 2A-3A, and it adopts arc plasma form.

8. A thermal coal lump dehydration system using the thermal coal lump separation and dehydration process according to claim 2, characterized in that: The invention comprises a roller screen (D) for turning over the coal blocks placed on the upper part, a venturi tube (C) for spraying a flocculant solution and a plasma spray gun (E) for forming a solidified hydrophobic film layer on the surface of the quick coal are respectively arranged on the roller screen (D), untreated lump coal is connected to the upstream of the roller screen (D), a sorting device (F) for sorting treated lump coal is connected to the downstream of the roller screen (D), and 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 port of the venturi tube (C), and an air compressor (B) for conveying air is connected to the air inlet of the venturi tube (C).

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