Filter pressing method for reducing the moisture content of filter pressed coal products

Abstract

The application discloses a filter pressing method for reducing the water content of filter pressed coal products, and applies a centrifugal filter pressing system to carry out filter pressing, wherein step 1, coal slurry is sent into a centrifuge through a centrifuge material stabilizing barrel, and centrifugal liquid is sent into a centrifugal liquid barrel after being treated by the centrifuge; step 2, coarse mixing is carried out in the centrifugal liquid barrel; and step 3, the centrifugal liquid after coarse mixing is pumped into a first-stage concentration tank, overflow liquid of the first-stage concentration tank is sent into a second-stage concentration tank, and underflow of the first-stage and the second-stage is sent into a filter press feeding barrel through an underflow pump, material in the filter press feeding barrel is sent to a plate-and-frame filter press through a filter press feeding pump, filter pressing is carried out through the plate-and-frame filter press, and filter pressing liquid is sent into the second-stage concentration tank, in the process, anionic PAM reagent is added to the first-stage concentration tank, the second-stage concentration tank and corresponding material stabilizing barrels and pipelines, and filter pressing is completed. Through the method, the purpose of reducing the water content of filter pressed coal is achieved, and economic benefits are improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of coal processing, and relates to a filter pressing method for reducing the water content of filter pressed coal products. BACKGROUND

[0002] The future coal is crushed and mixed with water in a certain proportion to form a coal slurry, which is transported to a storage tank by a pump delivery system, the coal slurry in the storage tank is transported to a dehydration workshop for dehydration, and the dewatered coal product is obtained by processing in the centrifugal filter pressing system in the dehydration workshop, and then is transported out for sale. During the operation of the dehydration system, there is a problem of high moisture content of the dewatered product, which affects the sale of the product coal. SUMMARY

[0003] The present application aims to provide a filter pressing method for reducing the water content of filter pressed coal products, which can reduce the moisture content of filter pressed coal.

[0004] The technical solution adopted by the present application is that the filter pressing method for reducing the water content of filter pressed coal products is processed by a centrifugal filter pressing system, and is implemented according to the following steps:

[0005] Step 1, the coal slurry is sent into a centrifuge through a centrifuge stable bucket, and the centrifugal liquid enters a centrifugal liquid bucket after being processed by the centrifuge;

[0006] Step 2, the coal slurry in the centrifuge stable bucket is mixed with the centrifugal liquid in the centrifugal liquid bucket;

[0007] Step 3, the mixed centrifugal liquid is pumped into a first-stage concentration tank, the overflow liquid of the first-stage concentration tank enters a second-stage concentration tank, the underflow of the first stage and the second stage is pumped into a filter press feed tank by an underflow pump, the material in the filter press feed tank is sent to a plate-and-frame filter press by a filter press feed pump, and the filter pressing is performed by the plate-and-frame filter press, and the filter pressing liquid enters the second-stage concentration tank, and in this process, anionic PAM reagent is added to the first-stage concentration tank, the second-stage concentration tank, and the corresponding stable bucket and pipeline, and the filter pressing is completed.

[0008] The present application is also characterized in that,

[0009] Step 1 controls the amount of the centrifuge stable bucket going to the centrifugal liquid bucket by a valve, and detects the flow rate by a flow meter.

[0010] The mixing amount is calculated as follows:

[0011] The centrifugal liquid concentration before mixing is calculated according to formula (1),

[0012] (1)

[0013] In formula (1), C1 is the measured concentration of the raw coal slurry buffer tank, %, M1 is the moisture content of the centrifugal coal, %, C2 is the centrifugal liquid concentration before mixing, %, and R represents the coal slurry recovery rate, %.

[0014] According to the coal slurry density under different coal slurry concentrations, the coarse mixing amount is calculated according to formula (2),

[0015] C2Q1 1+C3Q2 2=C4(Q1+Q2) 4(2)

[0016] In formula (b), C2 is the concentration of the centrifugal liquid before coarse mixing, %, Q1 is the treatment amount of the centrifugal liquid, m 3 / h, 1 is the coal slurry density corresponding to C2, t / m 3 , C3 is the coal slurry concentration, %, Q2 is the coarse mixing amount, m 3 / h, 2 is the coal slurry density corresponding to C3, t / m 3 , C4 is the concentration of the centrifugal liquid after coarse mixing, %, 4 is the coal slurry density corresponding to C4, t / m 3 .

[0017] The first-stage concentration tank and the second-stage concentration tank comprise a first-stage concentration tank body, a second-stage concentration tank body I connected in sequence, a first stable material bucket, a second stable material bucket, and a second-stage concentration tank body II, the second stable material bucket is further connected with the second-stage concentration tank body I, the first-stage concentration tank body and the second-stage concentration tank body I are connected with a filter press feeding tank, the filter press feeding tank is connected with a filter press, the filter press is connected with the second stable material bucket through a filter press liquid pipe, and the first stable material bucket is connected with a centrifugal liquid tank through a centrifugal liquid pipe;

[0018] Specifically, the step 3 is that anionic PAM agent is added to the inlet pipeline and the outlet pipeline of the first stable material bucket and the first stable material bucket, so that the centrifugal liquid after coarse mixing is fully mixed with the anionic PAM agent to obtain a first mixture, the first mixture is introduced into the first-stage concentration tank body for reaction, and the underflow in the first-stage concentration tank body after solid-liquid separation is introduced into the filter press feeding tank and then into the filter press for pressure filtration, and the overflow is introduced into the second-stage concentration tank body I;

[0019] Anionic PAM agent is added into the No. 2 stable material bucket, the connecting pipeline between the No. 2 stable material bucket and the pool body I of the second-stage concentration tank, the connecting pipeline between the No. 2 stable material bucket and the pool body II of the second-stage concentration tank and the filter inlet tank, the filtrate after pressure filtration of the underflow in the first-stage concentration tank is flowed into the pool body I of the second-stage concentration tank and the pool body II of the second-stage concentration tank through the No. 2 stable material bucket, in the process, the filtrate is fully mixed with the anionic PAM agent, and the anionic PAM agent is mixed and reacted in the pool body I of the second-stage concentration tank and the pool body II of the second-stage concentration tank, the underflow in the pool body I of the second-stage concentration tank is flowed into the filter inlet tank, and the underflow in the pool body I of the second-stage concentration tank and the underflow in the first-stage concentration tank are pressure filtered by the filter, and the obtained filtrate is repeated the foregoing operation process to complete the pressure filtration.

[0020] The total dosage of the anionic PAM agent is 40-50 mg / L.

[0021] The dosage of the anionic PAM agent at each position accounts for 35%-45% of the total dosage of the anionic PAM agent, the dosage of the anionic PAM agent in the No. 2 stable material bucket, the connecting pipeline between the No. 2 stable material bucket and the pool body I of the second-stage concentration tank and the connecting pipeline between the No. 2 stable material bucket and the pool body II of the second-stage concentration tank accounts for 12%-18% of the total dosage of the anionic PAM agent, the total dosage of the anionic PAM agent added into the filter inlet tank accounts for 40%-50% of the total dosage of the anionic PAM agent, and the sum of the dosages of the anionic PAM agent at the above positions accounts for 100% of the total dosage of the anionic PAM agent.

[0022] The present application has the following beneficial effects:

[0023] The present application is a pressure filtration method for reducing the water content of pressure-filtered coal products, which changes the adding mode of the agent, adjusts the adding amount of the agent and adopts the coarse mixing mode to achieve the above-mentioned purpose of reducing the water content of the pressure-filtered coal products and improve the economic benefits. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a structural schematic diagram of a centrifugal pressure filtration system;

[0025] Figure 2 is a position diagram of the dosing points of a first-stage concentration tank and a second-stage concentration tank of the centrifugal pressure filtration system.

[0026] In the figure, 1 is a centrifuge, 2 is a centrifuge stable material bucket, 3 is a centrifugal liquid tank, 4 is a first-stage concentration tank, 5 is a second-stage concentration tank, 6 is underflow, 7 is an underflow pump, 8 is a filter inlet tank, 9 is a filter inlet pump, 10 is a plate-and-frame filter, 11 is a PAC dosing machine, 12 is a PAM dosing machine, 13 is a valve, 14 is a flow meter, 15 is a mounting pipeline and 16 is a dosing pipeline. DETAILED DESCRIPTION

[0027] The present application will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0028] The present application is a filter pressing method for reducing the moisture content of filter pressed coal products, which applies a centrifugal filter pressing system as shown in Figure 1 and is implemented according to the following steps:

[0029] Step 1: The coal slurry is sent into the centrifuge 1 through the centrifuge stable bucket 2, and the centrifugal liquid is sent into the centrifugal liquid bucket 3 through the pipeline 15 after being processed by the centrifuge 1. This step controls the amount of the centrifugal liquid from the centrifuge stable bucket 2 to the centrifugal liquid bucket 3 through the valve 13, and uses the flow meter 14 to detect the flow. The opening of the valve 13 is adjusted according to the flow size.

[0030] Step 2: Coarse mixing is performed in the centrifugal liquid bucket 3.

[0031] The coarse mixing amount is calculated as follows:

[0032] The centrifugal liquid concentration before coarse mixing is calculated according to formula 1,

[0033] (1)

[0034] In formula (1), C1 is the measured concentration of the raw coal slurry buffer tank, %, M1 is the moisture content of the centrifugal coal, %, C2 is the centrifugal liquid concentration before coarse mixing, %, and R represents the coal slurry recovery rate, %.

[0035] The coarse mixing amount is calculated according to the coal slurry density under different coal slurry concentrations and according to formula 2,

[0036] C2Q1 1+C3Q2 2=C4(Q1+Q2) 4(2)

[0037] In formula (2), C2 is the centrifugal liquid concentration before coarse mixing, %, Q1 is the centrifugal liquid processing amount, m 3 / h, 1 is the coal slurry density corresponding to C2, t / m 3 , C3 is the coal slurry concentration, %, Q2 is the coarse mixing amount, m 3 / h, 2 is the coal slurry density corresponding to C3, t / m 3 , and C4 is the centrifugal liquid concentration after coarse mixing, %. 4 is the coal slurry density corresponding to C4, %.

[0038] Step 3, the centrifugal liquid after mixing with coarse is pumped to a first concentration tank, the overflow of the first concentration tank 4 enters a second concentration tank 5, the underflow of the first and second concentration tanks is pumped to a filter feed tank by an underflow pump, the material in the filter feed tank is sent to a plate and frame filter by a filter feed pump, and the plate and frame filter 10 is used for pressure filtration, and the pressure filtrate enters the second concentration tank 5, in the process, anionic PAM agent is added to the first concentration tank 4, the second concentration tank 5, and the corresponding material stabilizing tank and pipeline, and the pressure filtration is completed.

[0039] As shown in Figure 2 , the first concentration tank and the second concentration tank comprise a first material stabilizing tank, a first concentration tank body, a second concentration tank body I connected in sequence, a second material stabilizing tank, and a second concentration tank body II, the second material stabilizing tank is further connected with the second concentration tank body I, the first concentration tank body and the second concentration tank body I are connected with a filter feed tank, the filter is connected with the filter feed tank, the filter is connected with the second material stabilizing tank through a pressure filtrate pipe, the pressure filtrate treatment capacity is 245.52 m 3 / h, the first material stabilizing tank is connected with a centrifugal liquid tank through a centrifugal liquid pipe, the centrifugal liquid treatment capacity is 668.38 m 3 / h, and the treatment capacity of the filter feed tank is 700 m 3 / h

[0040] Step 3 is specifically that anionic PAM agent is added to the inlet pipeline and outlet pipeline of the first material stabilizing tank and the first material stabilizing tank, so that the centrifugal liquid after mixing with coarse is fully mixed with the anionic PAM agent to obtain a first mixture, the first mixture is introduced into the first concentration tank body for reaction, the underflow in the first concentration tank body after solid-liquid separation enters the filter feed tank, and the overflow enters the second concentration tank body I;

[0041] Anionic PAM agent is added to the second material stabilizing tank, the connecting pipeline between the second material stabilizing tank and the second concentration tank body I, and the connecting pipeline between the second material stabilizing tank and the second concentration tank body II, the pressure filtrate after the underflow in the first concentration tank body is filtered by the filter flows into the second concentration tank body I and the second concentration tank body II through the second material stabilizing tank, in the process, the filtrate is fully mixed with the anionic PAM agent, and the anionic PAM agent is mixed and reacted in the second concentration tank body I and the second concentration tank body II, solid-liquid separation is performed, the underflow in the second concentration tank body I enters the filter feed tank, and the filter performs pressure filtration treatment on the underflow in the second concentration tank body I and the underflow in the first concentration tank body, and the obtained pressure filtrate is repeatedly subjected to the foregoing operation process, and the pressure filtration is completed.

[0042] The total dosage of the anionic PAM agent is 40-50 mg / L. The dosage of the anionic PAM agent at each position accounts for 35%-45% of the total dosage of the anionic PAM agent, the dosage of the anionic PAM agent in the second stable material tank, the connecting pipeline between the second stable material tank and the pool body I of the second thickener, and the connecting pipeline between the second stable material tank and the pool body II of the second thickener accounts for 12%-18% of the total dosage of the anionic PAM agent, the total dosage of the anionic PAM agent in the filter feeding tank accounts for 40%-50% of the total dosage of the anionic PAM agent, and the sum of the dosages of the anionic PAM agent at the above positions accounts for 100% of the total dosage of the anionic PAM agent. Preferably, the total dosage of the anionic PAM agent in the inlet pipeline, the outlet pipeline of the first stable material tank and the first stable material tank accounts for 41.41% of the total dosage of the anionic PAM agent, the dosage of the anionic PAM agent in the second stable material tank, the connecting pipeline between the second stable material tank and the pool body I of the second thickener, and the connecting pipeline between the second stable material tank and the pool body II of the second thickener accounts for 15.22% of the total dosage of the anionic PAM agent, and the total dosage of the anionic PAM agent in the filter feeding tank accounts for 43.37% of the total dosage of the anionic PAM agent.

[0043] Since the current dosing position is located in the first thickener 4 and the second thickener 5, the size of the thickener is large (35 meters in diameter and 45 meters in diameter, respectively), and it is difficult to mix the agent uniformly in the thickener, so the coal slime settling performance is not good after adding the agent, and the thickener underflow concentration is not high, so a new dosing pipe 16 is installed to add the insufficient PAM agent to the filter feeding tank 8. The total effective volume of the filter feeding tank is 300 m 3 , the residence time is 25.7 min, the agent and the coal slurry can be mixed well, the filter feeding concentration and particle size can be improved, and the moisture content of the filter coal can be reduced from 28% to 23%.

[0044] In order to verify the adding effect of the anionic PAM agent in the filter method for reducing the moisture content of the filter coal product, the following experiments are compared:

[0045] Two kinds of coal slime, PAC (with a concentration of 2%), different types of PAM, cationic PAM, non-ionic PAM and anionic PAM (model ① 1400-1700 million, model ② 16 00-1800 million, model ③ 18 00-2100 million) and cationic PAM used in the thickening workshop are taken, and the PAM concentration is 1 ‰.

[0046] The flocculation experiment adopts two ways, one is to directly add PAM, and the other is to use PAC+PAM. 100 mL of coal slurry is taken into a measuring cylinder, and PAC and PAM are added in turn. The results are shown in Table 1.

[0047] Table 1 Flocculation and sedimentation results of PAM and PAC+PAM

[0048]

[0049] According to the above table, 1) the cationic PAM has the worst effect, and has no flocculation and sedimentation effect. Since the solid content in the coal slurry is relatively high, it is relatively stable, and the addition of PAC cannot effectively flocculate and settle;

[0050] 2) The addition of non-ionic and anionic PAM has good effect, but the dosage is relatively large, which is similar to sludge concentration;

[0051] 3) The supernatant of non-ionic PAM is relatively clear, but the anionic PAM flocculation settles quickly;

[0052] 4) The centrifugal liquid with coarse residue is the most referential, so the anionic PAM No. ② (1600-1800 million) is selected;

[0053] The optimal molecular weight type is determined by experiment as follows:

[0054] Table 2 Flocculation and sedimentation results of anionic PAM of various types

[0055]

[0056] According to Table 1 and Table 2, 1) the cationic PAM and the on-site PAM have no flocculation and sedimentation effect; the addition of PAC cannot effectively flocculate and settle, but has the opposite effect, and the dosage of PAM needs to be increased, so PAC should not be added;

[0057] 2) The centrifugal liquid with coarse residue is referential, and the anionic PAM No. ② (1600-1800 million) should be selected after screening, and the optimal addition amount is 40 mg / L.

[0058] Calculation of coarse amount:

[0059] Table 3 Density of coal slurry under different concentrations

[0060]

[0061] According to the density of coal slurry under different concentrations in Table 3, the coarse amount is calculated as follows:

[0062] Calculation of centrifugal liquid concentration before coarse addition:

[0063] (1)

[0064] In formula (1): C1 - measured concentration of raw coal slurry buffer tank, %; M1 - centrifugal coal moisture content, %; C2 - centrifugal liquid concentration, %; R represents coal slurry recovery rate;

[0065] In the above formula: R = 75%, C1 = 40%, M1 = 21%, C2 = 16% is calculated from the above formula.

[0066] C2Q1 1+C3Q2 2=C4(Q1+Q2) 4(2)

[0067] In formula (2): C2 - centrifugal liquid concentration before mixing coarse, %; calculated as 16% from formula (a); Q1 - centrifugal liquid treatment capacity, m 3 / h; calculated as 668.38 m 3 / h; p1 - 16% coal slurry density; C3 - coal slurry concentration, %; calculated as 52% according to test data; Q2 - coarse mixing amount, m 3 / h, to be solved; p2 - 52% coal slurry density; C4 - centrifugal liquid concentration after mixing coarse, calculated as above, the feed concentration of filter press needs to reach 21%, the concentration of centrifugal liquid after mixing coarse needs to reach 18%, C4 is taken as 18%; p4 - 18% coal slurry density;

[0068] The density is shown in Table 3, the above data is brought into formula (c) for calculation, and Q2 = 35.97 m 3 / h is obtained

[0069] C2Q1 1+C3'Q2 2= C4'Q3 3(3)

[0070] In formula (3), C2 - centrifugal liquid concentration before mixing coarse, %; calculated as 16% from formula (a); Q1 - centrifugal liquid treatment capacity, m 3 / h; calculated as 668.38 m 3 / h; p1 - 16% coal slurry density; C3' - coal slurry concentration, %; calculated as 52% according to test data; Q2 - coarse mixing amount, m 3 / h; to be solved; p2 - 52% coal slurry density; C4' - filter press feed concentration, %; taken as 21%; Q3 - total feed flow of on-site filter system, m 3 / h; flowmeter display data, taken as 700 m 3 / h; p3 - 21% coal slurry density;

[0071] Density is seen in Table 3, and the above data is brought into formula (c) to calculate, Q2=73.49 m 3 / h.

[0072] Coarse particles are added to improve the filter press feed size, and the addition position has two places, 1 is added in the centrifugal liquid barrel, and 2 is added to the filter press feed barrel, and the addition amount is different. Reduce the moisture content of the filter coal, and the filter press feed concentration needs to reach 21%, coarse mixing can be carried out. According to the calculation, the centrifugal liquid concentration before mixing coarse is 16%, and according to the measured data, the centrifugal liquid concentration can be increased by 3% after being concentrated by the first and second concentration pools, so in order to reach the requirement of the filter press feed concentration 21%, if coarse mixing is added in the centrifugal liquid barrel, the centrifugal liquid concentration after mixing coarse needs to reach 18%; through formula (2), the coarse mixing amount is 39.43 m 3 / h, if coarse mixing is added in the filter press liquid feed barrel, the concentration in the filter press liquid feed barrel needs to reach 21%, and according to formula (3), the coarse mixing amount is 73.49 m 3 / h. But according to the calculation, if coarse mixing is carried out in the filter press liquid feed barrel, the sum of the filter coal treatment capacity and the coarse mixing amount will be greater than the filter press treatment capacity, so coarse mixing is not feasible at this point.

[0073] As can be seen from the above, the filter press method for reducing the moisture content of filter coal products is used, the dosing mode is adjusted, the dosing amount is increased, the coarse mixing mode is adjusted, and the on-site process is adjusted, so as to improve the filter press feed concentration and reduce the moisture content of the filter coal. The calorific value can be increased by 4118kJ per point of reduction of the moisture content of the filter coal, the price of raw coal increases by about 0.1 yuan / t per 1kcal / kg increase of the calorific value, the annual output of filter coal is 2 million tons, the moisture content of the filter coal can be reduced from 28% to 23%, and the profit can be increased by 980 million yuan per year, which can produce very high economic benefits.

Claims

1. A filter pressing method for reducing the moisture content of filter pressed coal product, filter pressing being carried out using a centrifugal filter pressing system, characterised in that, The specific implementation is as follows: Step 1, the coal slurry is sent into the centrifuge (1) through the centrifuge material stabilizing barrel (2), and the centrifugal liquid is sent into the centrifugal liquid barrel (3) after being treated by the centrifuge (1); The step 1 controls the amount of the centrifuge material stabilizing barrel (2) to the centrifugal liquid barrel (3) through the valve (13), and detects the flow rate by using the flow meter (14); Step 2, coarse mixing is carried out in the centrifugal liquid barrel (3); The amount of coarse mixing is calculated as follows: The centrifugal liquid concentration before coarse mixing is calculated according to formula (1), （1） In formula (1), C1 is the measured concentration of the raw coal slurry buffer tank, %; M1 is the moisture content of the centrifugal coal, %; C2 is the centrifugal liquid concentration before coarse mixing, %; R represents the coal slurry recovery rate, %; The coarse mixing amount is calculated according to the coal slurry density under different coal slurry concentrations and according to formula (2), （2） In formula (2): C2 is the concentration of centrifugal liquid before mixing coarse, %; Q1 is the processing capacity of centrifugal liquid, m 3 / h, 1 is the coal slurry density corresponding to C2, t / m 3 , C3 is the coal slurry concentration, %; Q2 is the mixing coarse amount, m 3 / h, 2 is the coal slurry density corresponding to C3, t / m 3 , C4 is the concentration of centrifugal liquid after mixing coarse, % 4 is the coal slurry density corresponding to C4, t / m 3 ; Step 3, the centrifugal liquid after coarse mixing is pumped into the first concentration tank (4), the overflow of the first concentration tank (4) is sent into the second concentration tank (5), the underflow of the first concentration tank (4) and the second concentration tank (5) is pumped into the filter press feed barrel through the underflow pump, the material in the filter press feed barrel is sent to the plate and frame filter press through the filter press feed pump, and the filter press is carried out through the plate and frame filter press (10), the filter liquid is sent to the second concentration tank (5), and the process is completed by adding anionic PAM agent to the first concentration tank (4), the second concentration tank (5), and the corresponding first and second concentration tanks (5) and the corresponding second concentration tank (5) pipeline, and the filter pressing is completed; The first concentration tank (4) and the second concentration tank (5) comprise a first concentration tank, a first concentration tank body, a second concentration tank body I connected in sequence, a second concentration tank body II, and a second concentration tank body I connected with the second concentration tank body II, and the first concentration tank body and the second concentration tank body I are connected with the filter press feed barrel, the filter press feed barrel is connected with the filter press, the filter press is connected with the second concentration tank through the filter liquid pipe, and the first concentration tank is connected with the centrifugal liquid barrel through the centrifugal liquid pipe; The step 3 is specifically that the anionic PAM agent is added to the inlet pipeline, outlet pipeline and first concentration tank of the first concentration tank, the centrifugal liquid after coarse mixing is fully mixed with the anionic PAM agent to obtain a first mixture, the first mixture is introduced into the first concentration tank body for reaction, the underflow in the first concentration tank body after solid-liquid separation is introduced into the filter press feed barrel, and then introduced into the filter press from the filter press feed barrel, and the overflow is introduced into the second concentration tank body I. The anionic PAM agent is added into the No. 2 stable material barrel, the connecting pipeline between the No. 2 stable material barrel and the pool body I of the second concentration tank, the connecting pipeline between the No. 2 stable material barrel and the pool body II of the second concentration tank, and the filter feeding barrel. The filter cake after the underflow in the first concentration tank is filtered by the filter is flowed into the pool body I of the second concentration tank and the pool body II of the second concentration tank through the No. 2 stable material barrel. In this process, the filter cake is fully mixed with the anionic PAM agent, and the anionic PAM agent is mixed and reacted in the pool body I of the second concentration tank and the pool body II of the second concentration tank. The underflow in the pool body I of the second concentration tank is fed into the filter feeding barrel, and the filter cake in the pool body I of the second concentration tank and the underflow in the first concentration tank are filtered by the filter. The obtained filter cake is subjected to the above-mentioned operation process repeatedly, and the filter is completed.

2. The pressure filtration method for reducing the moisture content of a pressure filtered coal product according to claim 1, characterized in that, The total amount of the anionic PAM agent is 40-50 mg / L, that is, 40-50 mg of the agent is added into 1 L of coal slurry.

3. The pressure filtration method for reducing the moisture content of a pressure filtered coal product according to claim 2, characterized in that, The total amount of the anionic PAM agent is 40-50 mg / L, that is, 40-50 mg of the agent is added into 1 L of coal slurry. The total amount of the anionic PAM agent is 40-50 mg / L, that is, 40-50 mg of the agent is added into 1 L of coal slurry.

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