Device for preparing coal water slurry through coal gasification fine slag flotation

Abstract

The utility model discloses a device for preparing coal water slurry through coal gasification fine slag flotation, which comprises a settling tank and is characterized in that the device further comprises a grading flotation tank and a coal mill, fine slag slurry at the bottom of the settling tank is pumped out through an underflow pump of the settling tank and sent to the grading flotation tank, and the coal mill is connected with the grading flotation tank. Fine slag slurry is separated into scum slurry and tailings in the grading flotation tank, the scum slurry overflows out of the grading flotation tank and is discharged to a coal mill to be mixed with raw coal, water and an additive to prepare water-coal slurry, and the tailings are discharged through a slag discharging opening in the bottom of the grading flotation tank after being subjected to gravity settling. The device disclosed by the utility model can realize efficient separation of gasified slag and slurry grading flotation to recover carbon-rich particles, so that the utilization efficiency of coal is improved, and the solid waste discharge of coal chemical enterprises is reduced.

Description

TECHNICAL FIELD

[0001] The utility model belongs to coal gasification technical field, concretely relates to a device for preparing coal water slurry by coal gasification fine slag flotation. BACKGROUND

[0002] Water coal slurry pressurized gasification is the mainstream gasification technology of the current large-scale development of coal chemical industry, which uses water coal slurry as raw material, and the coal slurry feeding pump is used to pressurize and send into the gasification furnace to carry out gasification reaction with oxygen, and has the characteristics of high carbon conversion rate, low pollutant emission and long running time. The water coal slurry as raw material is prepared by adding raw coal, water and additives into the coal mill in a certain proportion for grinding.

[0003] In the gas flow bed gasification process, the unreacted coal and synthesis gas enter the quenching chamber together, and after quenching, the obtained slag collected through the gasification furnace bottom is coarse slag, and the fine slag removed by the dust removal device is carried by the synthesis gas. Due to the overall oxygen deficiency reaction in the gasification process, the ignition loss of the gasification slag is generally high, especially the gasification fine slag, and the residual carbon content is 10%-50%. The gasification slag is the residue of high-temperature gasification reaction, and the residual carbon activity is poor and mixed with ash slag. At present, it is mainly stacked and landfilled, not only occupies land resources, but also causes potential pollution to soil and water, and has become a problem that needs to be solved for modern coal chemical enterprises to realize sustainable development.

[0004] If the carbon extraction and quality separation of coal gasification slag can reduce the ignition loss, it will be beneficial to realize its application in the field of building materials. At the same time, the carbon-rich product obtained by quality separation can also be used as high-calorific-value gasification raw material or fuel, therefore, carbon extraction and quality separation is the key to realize the resource utilization of coal gasification slag. SUMMARY

[0005] The utility model discloses a device for preparing coal water slurry by coal gasification fine slag flotation, which can realize efficient separation of coal gasification fine slag, recover carbon-rich particles by flotation to prepare coal water slurry, reduce the ignition loss of tailings, and realize harmless and resource utilization of gasification fine slag, thereby significantly improving the resource utilization efficiency of coal and reducing the solid waste discharge of coal chemical enterprises.

[0006] To achieve the above-mentioned purposes, the utility model adopts the following technical scheme:

[0007] A device for preparing coal water slurry by coal gasification fine slag flotation, comprising a settling tank, characterized in that the device further comprises a classification flotation tank and a coal mill, fine slag slurry at the bottom of the settling tank is pumped out by a settling tank bottom flow pump, and the fine slag slurry is sent to the classification flotation tank, the fine slag slurry is separated into float slag slurry and tailings in the classification flotation tank, the float slag slurry overflows out of the classification flotation tank and is discharged to the coal mill to prepare coal water slurry, and the tailings are discharged through a classification flotation tank bottom discharge port after gravity settling.

[0008] Further, the grading flotation tank comprises a tank body, the bottom of the tank body is provided with a feeding pipe, the upper portion of the tank body is provided with a scum outlet, the lower portion of the tank body is provided with a residue outlet, and a stirring paddle is arranged in the tank body.

[0009] Further, the paddle blade of the stirring paddle is in the structure of an impeller.

[0010] The device for preparing coal water slurry by flotation of coal gasification fine residue, when the fine residue slurry enters the grading flotation tank, due to the existence of particles (carbon, ash and carbon-ash combined state) with different densities and particle sizes in the fine residue slurry, the particles have different settling velocities in the grading flotation tank. Under the joint action of the upward slurry flow at the bottom of the grading flotation tank and the stirring impeller, the particles with small density and particle size (particle size: 0.074-0.5 mm) (mainly carbon-rich particles) in the fine residue slurry are preferentially concentrated in the upper portion of the grading flotation tank, overflow to form a scum slurry, and the tailings (low-carbon particles with low loss on ignition) with high density and large particle size (particle size > 0.5 mm) sink to the bottom of the tank. By adjusting the stirring speed of the impeller and the slurry flow rate, the floating and settling velocities of the fine residue particles can be changed, and efficient separation of the gasification fine residue can be realized.

[0011] Further, the stirring paddle is driven by a variable frequency motor. Preferably, the variable frequency motor has a power of 3KW and a constant torque speed of 5-50H Z .

[0012] Preferably, the feeding flow rate of the fine residue slurry of the grading flotation tank (7) is 6-10 m / h, and the rotating speed of the impeller is 1300-1500 r / min.

[0013] According to the device for preparing coal water slurry by flotation of coal gasification fine residue, the fine residue slurry at the bottom of the settling tank is sent to the grading flotation tank, the carbon-ash particles are separated under the joint action of the upward slurry flow at the bottom of the grading flotation tank and the stirring paddle impeller, the carbon-rich scum slurry overflows out of the flotation tank under the driving of the slurry flow and is discharged to the inlet of the coal mill, and the qualified coal water slurry is prepared by mixing the carbon-rich scum slurry with raw coal, water and coal water slurry additives.

[0014] Beneficial effects: the device for preparing coal water slurry by flotation of coal gasification fine residue realizes efficient separation of the coal gasification fine residue through the action of the impeller stirring and the slurry flow rate, recovers the carbon-rich particles by flotation to prepare the coal water slurry, reduces the loss on ignition of the tailings, thereby improving the utilization efficiency of the coal, reducing the solid waste discharge amount of the coal chemical enterprise, and realizing the resource utilization of the gasification fine residue of the coal chemical enterprise. BRIEF DESCRIPTION OF DRAWINGS

[0015] Fig. 1 is a structural schematic view of the device for preparing coal water slurry by flotation of coal gasification fine residue according to the present application;

[0016] Among them, 1 is a settling tank, 2 is a settling tank bottom flow pump, 3 is a grading flotation tank feeding valve, 4 is a filter press feeding valve, 5 is a filter press, 6 is a grading flotation tank stirring paddle, 7 is a grading flotation tank, 8 is a coal mill, and 9 is an impeller. Detailed Implementation

[0017] The technical solution of this utility model will be further described in detail below through specific embodiments. However, it should be noted that the following embodiments are only used to describe the content of the invention and do not constitute a limitation on the protection scope of this utility model.

[0018] like Figure 1 As shown, the present invention discloses an apparatus for producing coal-water slurry by flotation of fine slag from coal gasification, comprising a settling tank 1, a settling tank underflow pump 2, a classifying flotation tank feed valve 3, a filter press feed valve 4, a filter press 5, a classifying flotation tank agitator 6, a classifying flotation tank 7, and a coal mill 8.

[0019] High-temperature black water discharged from gasifiers and other sources is concentrated through flash evaporation and then enters settling tank 1. The fine slurry at the bottom of settling tank 1 is pumped out by the underflow pump 2 and originally sent to filter press 5, where it is pressed into fine ash and transported as solid waste by a slag truck. In this unit, by opening the feed valve 3 of the classifying flotation cell and closing the feed valve 4 of the filter press, the fine slurry is changed from being sent to filter press 5 to being sent to the classifying flotation cell 7. Under the combined action of the rising slurry flow at the bottom of the classifying flotation cell 7 and the impeller 9 on the agitator 6, the upper part consists of scum with a lower specific gravity, while the lower part consists of tailings with a higher specific gravity. Driven by the slurry flow, the scum overflows from the classifying flotation cell 7 and is discharged to the coal mill 8, where it is mixed with raw coal, water, and additives to produce qualified coal-water slurry. The tailings are discharged through the slag discharge port at the bottom of the classifying flotation cell 7 after gravity settling.

[0020] The aforementioned flotation cell 7 includes a cell body, with a feed pipe at the bottom, a scum outlet at the top, and a scum discharge outlet at the bottom. A flotation cell agitator 6 is installed inside the cell body. The flotation cell agitator 6 is driven by a variable frequency motor, and the blade structure is an impeller structure. The variable frequency motor has a power of 3KW and a constant torque speed regulation of 5-50Hz. Z .

[0021] The device utilizes the combined action of the rising slurry flow at the bottom of the flotation cell and the agitator impeller under a certain flow rate to separate carbon and ash particles from the gasification slag. Under conditions of a slurry flow rate of 6 m / h and an impeller speed of 1500 r / min, experimental data showed that the particles (0.074-0.5 mm) in the flotation slag were mainly carbon-rich particles, with a slag loss on ignition of 80% and a combustible material recovery rate of 65%. The coal-water slurry prepared by mixing the recovered fine slurry with raw coal, water, and additives met production requirements in terms of slurry formation and flowability.

Claims

1. A device for coal gasification fine slag floatation for preparing coal water slurry, comprising a settling tank (1), characterized in that, The device further comprises a classification flotation tank (7) and a coal mill (8), fine slurry at the bottom of the sedimentation tank (1) is pumped out by a sedimentation tank bottom flow pump (2), and is sent to the classification flotation tank (7), the fine slurry is separated into float slurry and tailings in the classification flotation tank (7), the float slurry overflows from the classification flotation tank (7) and is discharged to the coal mill (8) to prepare water coal slurry, and the tailings is discharged through a tailings discharge port at the bottom of the classification flotation tank (7) after gravity settling.

2. The apparatus for coal gasification fine slag floatation for preparing coal water slurry according to claim 1, characterized in that, The classification flotation tank (7) comprises a tank body, a feed pipe at the bottom of the tank body, a float slurry outlet at the upper part of the tank body, and a tailings discharge port at the lower part of the tank body, and a stirring paddle (6) is arranged in the tank body.

3. The apparatus for coal gasification fine slag floatation for preparing coal water slurry according to claim 2, characterized in that, The paddle blade of the stirring paddle (6) is a impeller structure (9).

4. The apparatus for coal gasification fine slag floatation for preparing coal water slurry according to claim 2, characterized in that, The stirring paddle (6) is driven by a variable frequency motor, the variable frequency motor has a power of 3KW and a constant torque speed of 5-50H Z .

5. The apparatus for coal gasification fine slag floatation for coal water slurry of claim 1, wherein, The feed flow rate of the fine slurry of the classification flotation tank (7) is 6-10 m / h.

6. The apparatus for coal gasification fine slag floatation for preparing coal water slurry according to claim 3, characterized in that, The rotating speed of the impeller structure (9) is 1300-1500 r / min.

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