CN110790469A - Process and device for improving pressure filtration performance of tail coal slime by coal gasification fine slag - Google Patents

Abstract

The invention discloses a process and a device for improving the pressure filtration performance of tailing slurry by coal gasification fine slag, and the process comprises the following steps: mixing the coal gasification fine slag and the tail coal slime pressure filtration filtrate to prepare coal gasification fine slag slurry; adding the coal gasification fine slag slurry into the tail coal slime pulp, and fully mixing; carrying out filter pressing and dehydration on the tailing slurry added with the coal gasification fine slag slurry; and (3) shunting part of the filtrate generated in the filter pressing to prepare the coal gasification fine slag slurry. Because the coal gasification fine slag particles contain a large number of pores, the particle surfaces are rough, and the hydrophobicity is obviously higher than that of the tail coal mud. Due to the properties of the coal gasification fine slag, a large number of new drainage channels are formed in the tail coal slime, and the water in the tail coal slime is favorably and quickly discharged, so that the pressure filtration performance of the tail coal slime is improved, and the pressure filtration efficiency is improved.

Description

A process and device for improving the filter press performance of tailing slime with coal gasification fine slag

technical field

The invention belongs to the technical field of coal slime dehydration, in particular to a process and a device for improving the filtering performance of tail slime by adding coal gasification fine slag.

Background technique

At present, in the coal washing and processing, the flotation process is commonly used to separate the fine slime, and the flotation tailings enter the thickener, and then enter the filter press for dehydration after concentration, and then become the tail slime product after dehydration. At the same time, the filter press link is also an important link to realize the closed-circuit circulation of the coal slurry in the coal preparation plant. The high content of fine-grained gangue minerals in the tailings slime and the high potential on the particle surface make the treatment of the filter press more difficult. Low filtration efficiency will inevitably lead to an increase in the amount of slime in the slime water system and worsen production conditions. In order to improve the filter press efficiency, many coal preparation plants add flocculation/coagulation agents in the filter press process to promote the coagulation of fine particles into large flocs to improve the filter press efficiency. However, the large-scale use of chemicals will affect the quality of circulating water in the coal preparation plant and deteriorate production. At the same time, it increases the production cost of the enterprise. Therefore, the use of efficient, low-cost, and environmentally friendly methods to improve the filtration performance of tailings slime is of great significance to coal preparation plant production.

In the process of coal gasification process, coal gasification slag will be discharged. According to the different discharge methods, it can be divided into coarse slag and fine slag. The coarse slag refers to the residue discharged from the bottom of the gasification furnace, and the fine slag is Refers to the waste obtained by entraining coal gasification gas and then filtering through wet slag removal. The carbon content of coal gasification fine slag is relatively large, which generally accounts for more than 15% of the total fine slag, and even reaches 26% to 55%. A kind of solid waste that is difficult to use directly.

In terms of material composition and mineral structure, coal gasification fine slag is very different from power plant boiler fly ash and coal slag directly burned by coal. The coal gasification fine slag formed under high temperature and high pressure has a large number of pores and rough particle surface. The higher carbon content makes the overall hydrophobicity of the coal gasification fine slag higher. By adding the coal gasification fine slag to the tailings slime, the filtrate will be more easily discharged from the "drainage channel" formed by the coal gasification fine slag, which not only improves the efficiency of coal slime filtration, but also realizes the resource utilization of waste.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a process and device for improving the performance of medium-pressure filtration of tail slime with coal gasification fine slag, so as to improve the performance of tail slime and improve the efficiency of tail slime.

To achieve the above object, the technical scheme adopted in the present invention is:

A process for improving the filter press performance of tailings slime with coal gasification fine slag, comprising the following steps:

(1) Mixing coal gasification fine slag and tailing slime pressure filtration filtrate to prepare coal gasification fine slag slurry;

(2) adding the coal gasification fine slag slurry obtained in step (1) into the tailings slime slurry, and fully mixing;

(3) filter press dehydration to the tailings slime slurry obtained in step (2) and added with coal gasification fine slag slurry;

(4) A part of the filtrate produced in the pressure filtration in step (3) is diverted to prepare coal gasification fine slag slurry.

Preferably, in the step (1), in the coal gasification fine slag slurry, the concentration of the coal gasification fine slag is 600-900 kg/m ³ .

Preferably, in the step (2), the tailings slime slurry is calculated as dry slime, and the amount of coal gasification fine slag is as follows: 50-150 kg of coal gasification fine slag is added per t of dry slime.

A device for realizing the above-mentioned process for improving coal slime pressure filtration performance with coal gasification fine slag, including a thickener, a slurry mixing barrel, a filter press, a belt conveyor, and a coal gasification fine slag slurry mixing barrel, wherein: the thickener The bottom flow port of the ore slurry is connected to the inlet of the slurry mixing barrel through a pipeline, and a slurry pump is installed on the pipeline; the outlet of the slurry mixing barrel is connected to the inlet of the filter press through a pipeline, and the pipeline is provided with a feeding pump; The outlet of the filtrate is connected to the inlet of the gasification fine slag slurry mixing tank through a pipeline, and the filter cake outlet of the filter press is connected to a belt conveyor; the outlet of the gasification fine slag slurry mixing tank is connected to the outlet of the slurry pump through a pipeline. The pipeline is provided with a check valve and a flow valve.

The flow valve is used to adjust the addition amount of coal gasification fine slag.

The check valve is used to prevent the tailings slime slurry from flowing back to the coal gasification fine slag slurry mixing tank when the slurry pump stops working.

The outlet position of the coal gasification fine slag slurry mixing barrel is higher than the slurry pump.

Beneficial effects: the process and device of the present invention can improve the filter press performance of tail slime and improve the filter pressure efficiency of tail slime. Compared with the prior art, the present invention has the following advantages:

(1) The coal gasification fine slag used is an industrial waste with low cost, which greatly reduces the production cost compared with the commonly used chemical filter aids.

(2) The coal gasification fine slag has no influence on the water quality and will not pollute the circulating water of the coal preparation plant, which is beneficial to the smooth operation of each production link.

Description of drawings

Fig. 1 is the flow chart of the technology of the present invention;

Fig. 2 is the device connection schematic diagram of the present invention;

In Figure 2: 1- Thickener; 2- Slurry pump; 3- Slurry mixing bucket; 4- Feeding pump; 5- Filter press; 6- Belt conveyor; 7- Coal gasification fine slag slurry mixing bucket; 8 - Check valve; 9 - Flow valve.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings:

As shown in Figure 1, a kind of coal gasification fine slag of the present invention improves the technology of tail slime filter press performance, comprising the following steps:

(1) Mixing coal gasification fine slag and tailing slime pressure filtration filtrate to prepare coal gasification fine slag slurry, so that it has better fluidity, and the concentration of coal gasification fine slag slurry is preferably 600～900kg/m ³ , that is, the solid mass of coal gasification fine slag in 1m ³ slurry is 600-900kg;

(2) The slurry pump injects the tailings slime from the bottom flow hole of the thickener into the slurry mixing barrel. When the slurry pump is working, a negative pressure will be formed at its outlet, and the coal gasification fine slag slurry will be sucked into the tailings slime slurry, and subsequently The slurry mixing barrel is further mixed, and the tailings slime slurry is calculated as dry slime, and the amount of coal gasification fine slag added is preferably 50-150kg/t, that is, the mass of coal gasification fine slag added to 1 t of dry slime is 50-150kg;

(3) filter-press dehydration for the tailings slime slurry added with gasification fine slag;

(4) The filtrate produced by the pressure filtration and dehydration in step (3) is divided into the outflow part, which is used for preparing coal gasification fine slag slurry.

Because the particles of coal gasification fine slag contain a large number of pores, the surface of the particles is relatively rough. The higher carbon content makes the overall hydrophobicity of coal gasification fine slag significantly higher than that of tailing slime. These properties of the coal gasification fine slag make it easier for the filtrate to be quickly discharged from the "drainage channel" formed by it, thereby improving the filter press performance of the tailings slime and increasing the filter press efficiency.

As shown in Figure 2, the device for realizing the technology of improving the filtration performance of coal gasification fine slag according to the present invention includes a thickener 1, a slurry mixing barrel 3, a filter press 5, a belt conveyor 6, and a coal gasification fine slag slurry Body mixing barrel 7, wherein: the underflow port of the thickener 1 is connected to the inlet of the slurry mixing barrel 3 through a pipeline, and the pipeline is provided with a slurry pump 2; the outlet of the slurry mixing barrel 3 is connected to the filter press 5 through a pipeline. The inlet of the filter press 5 is provided with a feeding pump 4; the filtrate outlet of the filter press 5 is connected to the inlet of the gasification fine slag slurry mixing barrel 7 through the pipeline, and the filter cake outlet of the filter press 5 is connected to the belt conveyor 6; The outlet of the fine slag slurry mixing tank 7 is connected to the outlet of the slurry pump 2 through a pipeline, and the pipeline is provided with a check valve 8 and a flow valve 9 .

When the slurry pump 2 is working, a negative pressure will be formed at the outlet, and the coal gasification fine slag slurry will be sucked into the tailings slime slurry. The flow valve 9 is used to adjust the amount of coal gasification fine slag added, and the check valve 8 is used to prevent the slurry When the pump 2 stops working, the tailings slime slurry flows back to the coal gasification fine slag slurry mixing tank 7. The outlet position of the coal gasification fine slag slurry mixing barrel 7 should be higher than the slurry pump, so that the coal gasification fine slag slurry is easier to inhale. . The coal gasification fine slag and tailing slime are further stirred in the coal gasification fine slag slurry mixing barrel 7 to make the two more evenly mixed, and the tailings slime slurry mixed into the coal gasification fine slag is filtered by the filter press 5 After dehydration, a part of the removed filtrate is divided and fed into the coal gasification fine slag slurry mixing tank 7 , and the filter cake formed after pressure filtration is transported by the belt conveyor 6 .

Example:

A laboratory filtration test was carried out for the underflow of a thickener with a high content of fine mud. The slurry concentration was 500kg/m ³ , 100 mL of sample was taken, and 100 kg/t of coal gasification fine slag was added. After fully stirring with an impeller agitator, use a Buchner funnel to extract Filtration test, the test pressure is 0.1 MPa, the test is stopped when no filtrate is discharged at an interval of 10 seconds after suction filtration, and the final filtration time is recorded as 8 minutes and 20 seconds. Under the same test conditions, filtration was performed without adding coal gasification fine slag, and the final filtration time was 13 minutes and 50 seconds. The addition of coal gasification fine slag reduces the filtration time by 40% and significantly improves the filtration speed.

The above are only the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the principles of the present invention, several improvements and modifications can be made. It should be regarded as the protection scope of the present invention.

Claims (7)

1. a technique for improving the filter press performance of tailing slime by a coal gasification fine slag, is characterized in that: comprise the following steps: (1) Mixing coal gasification fine slag and tailing slime pressure filtration filtrate to prepare coal gasification fine slag slurry; (2) adding the coal gasification fine slag slurry obtained in step (1) into the tailings slime slurry, and fully mixing; (3) filter press dehydration to the tailings slime slurry obtained in step (2) and added with coal gasification fine slag slurry; (4) A part of the filtrate produced in the pressure filtration in step (3) is diverted to prepare coal gasification fine slag slurry. 2. the technique for improving tailing slime filter press performance by coal gasification fine slag according to claim 1, it is characterized in that: in described step (1), in coal gasification fine slag slurry, the concentration of coal gasification fine slag is 600～900kg/m ³ . 3. The technique for improving the performance of tailing slime filter press by coal gasification fine slag according to claim 1, characterized in that: in the step (2), the tailings slime slurry is calculated as dry slime, and the coal gasification fine slag is The dosage is: add 50-150kg of coal gasification fine slag per t of dry slime. 4. A device for realizing the coal gasification fine slag improvement technology of coal slime filter press performance according to claim 1, characterized in that: it comprises a concentrator (1), a slurry mixing barrel (3), a filter press (5). ), a belt conveyor (6), a coal gasification fine slag slurry mixing barrel (7), wherein: the underflow port of the thickener (1) is connected to the inlet of the slurry mixing barrel (3) through a pipeline, and the pipeline is provided with The slurry pump (2); the outlet of the slurry mixing barrel (3) is connected to the inlet of the filter press (5) through a pipeline, and the pipeline is provided with a feeding pump (4); the filtrate outlet of the filter press (5) passes through The pipeline is connected to the inlet of the gasification fine slag slurry mixing barrel (7), the filter cake outlet of the filter press (5) is connected to the belt conveyor (6); the outlet of the gasification fine slag slurry mixing barrel (7) is connected through the pipeline It is connected with the outlet of the slurry pump (2), and the pipeline is provided with a check valve (8) and a flow valve (9). 5. The device according to claim 4, characterized in that: the flow valve (9) is used to adjust the addition amount of coal gasification fine slag. 6. The device according to claim 4, characterized in that: the check valve (8) is used to prevent the tailings slime slurry from flowing back to the coal gasification fine slag slurry mixing bucket (2) when the slurry pump (2) stops working. 7). 7. The device according to claim 4, characterized in that: the outlet position of the coal gasification fine slag slurry mixing barrel (7) is higher than the slurry pump (2).

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