Mechanical hole breaking and vibration force field energizing coal gasification fine slag extrusion dewatering promotion method

Abstract

This invention discloses a method for promoting the extrusion and dehydration of fine coal gasification slag using mechanical pore breaking and vibration force field empowerment, comprising the following steps: grinding the fine coal gasification slag using a wet ball mill for 1-9 minutes to obtain a slurry; and determining the median particle size d of the carbon-containing fine coal gasification slag after grinding. 50 The particle size is 5.9–19.3 μm. The slurry is pretreated by vacuum filtration to obtain a vacuum filter cake with a moisture content of 47–53%. A vibration extrusion dewatering device is then used to dewater the gasified fine slag after grinding, yielding a filter cake with a moisture content of 29–36%. This method improves dewatering efficiency, reduces dewatering energy consumption, and achieves good dewatering results.

Description

A method for promoting the extrusion and dehydration of fine coal gasification slag using mechanical pore breaking and vibration force field empowerment. Technical Field

[0001] This invention belongs to the field of coal-based solid waste treatment technology, specifically relating to a method for promoting the extrusion and dewatering of fine coal gasification slag using mechanical pore breaking and vibration force field empowerment. Background Technology

[0002] Coal gasification refers to the process of using coal or coke as raw material and steam, oxygen (or air), hydrogen, etc., as gasifying agents to gasify the combustible components of coal or coke into combustible gases through a chemical reaction at high temperatures. The composition of the resulting combustible gas is similar to that of blast furnace gas. The coal gasification slag produced during the gasification process is a typical solid waste generated from a coal chemical process, mainly divided into two types: coarse slag and fine slag. The coarse slag is in a molten state at high temperatures and is discharged from the bottom of the furnace. If the gas flow rate in the gasifier is too fast, the reaction time between the pulverized coal and the gasifying agent is limited. The unreacted residual carbon, mixed with the molten ash particles generated from the complete reaction, forms the fine gasification slag, which is carried out by the coal gas.

[0003] Fine coal gasification slag is produced in a high-temperature, high-pressure gasifier and contains 20-40% unreacted carbon by mass. This residual carbon has highly developed pores, with a specific surface area reaching 145 m². 2 / g, abundant pores act as natural "storage rooms" for moisture, making it difficult for water to be removed from the pores and framework during the dehydration process, resulting in poor dehydration efficiency. In the extrusion dehydration process, as the pressure increases, the dehydration capacity initially increases and then slows down, reaching a bottleneck. Further increasing the pressure to a certain value, the high extrusion force can destroy the particle structure and further promote the dehydration process. This means that the destruction of the particle structure allows the particles to be arranged more tightly, destroying the "storage rooms" where moisture is hidden, forcing the moisture to transfer, and achieving further efficient dehydration.

[0004] Currently, before the gasification slag enters the dewatering process, flocculants such as polyacrylamide are generally used to flocculate the fine coal gasification slag. After concentration in the thickening tank, the slurry concentration increases from 2-3% to 8-20%, and then it enters the dewatering equipment (such as vacuum horizontal filter cloth machine, filter press, and horizontal screw centrifuge) for dewatering. These dewatering equipment generate dewatering force fields such as vacuum negative pressure, extrusion, and centrifugal force. Most of them use a single dewatering force field, which has disadvantages such as poor dewatering effect, low efficiency, and high energy consumption. Summary of the Invention

[0005] The purpose of this invention is to provide a method for promoting the extrusion and dehydration of fine coal gasification slag using mechanical pore breaking and vibration force field empowerment. This method can improve dehydration efficiency, reduce dehydration energy consumption, and achieve good dehydration effect.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is: a method for promoting the extrusion and dehydration of fine coal gasification slag using mechanical pore breaking and vibration force field empowerment, comprising the following steps:

[0007] (1) The coal gasification fine slag was ground using a wet ball mill. After grinding for 1-9 minutes, a slurry was obtained. The median particle size d of the carbon-containing coal gasification fine slag after grinding was determined. 50 The range is 5.9–19.3 μm;

[0008] (2) The slurry obtained in step (1) is pretreated by vacuum filtration to obtain a vacuum filter cake with a moisture content of 47-53%;

[0009] (3) The vacuum filter cake obtained in step (2) is subjected to vibration extrusion dewatering device to obtain a filter cake with a moisture content of 29-36%.

[0010] Preferably, in step (1), the median particle size d of the carbon-containing fine slag after grinding for 1 min is... 50 It is 19.3 μm.

[0011] Preferably, in step (1), the median particle size d of the carbon-containing fine slag after 3 minutes of grinding is... 50 It is 9.5μm.

[0012] Preferably, in step (1), the median particle size d of the carbon-containing fine slag after 6 minutes of grinding is... 50 It is 6.8μm.

[0013] Preferably, in step (1), the median particle size d of the carbon-containing fine slag after 9 minutes of grinding is... 50 It is 5.9 μm.

[0014] Preferably, in step (1), the ball mill speed is 100 r / min, the ball milling media accounts for 10 wt% of the mass of coal gasification fine slag, and the percentage of solid material in the slurry is 30%.

[0015] Preferably, in step (1), the specific surface area of ​​the coal gasification fine slag is 145 m². 2 / g, Loss on ignition (LOI) is 24%, Median particle size d of carbon content 50 It is 47μm.

[0016] Preferably, in step (3), the extrusion strength is 7-10 MPa, the vibration force is 2.3 MPa and the vibration frequency is 23-45 Hz, and the extrusion dehydration time is 1-5 min.

[0017] Preferably, in step (3), the inner diameter of the dewatering mold is 150 mm, and the amount of vacuum filter cake in each feeding step (2) is 2 kg.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] This invention employs a wet grinding method to grind particles in the black water of gasification slag. This grinding process disrupts the irregularly shaped, porous residual carbon structure. This process must achieve pore disruption while preventing excessively fine particles. Excessive grinding leads to the generation of more fine particles, increases specific surface area and water-holding capacity, but also increases the path length of the water removal process, which is detrimental to dehydration. This invention reduces the median particle size d of the carbon-containing particles in the coal gasification slag through grinding. 50 Maintaining the particle size between 5.9 and 19.3 μm yields optimal mechanical pore-breaking conditions. Subsequently, the material is placed in a vibration-extrusion composite dewatering system. During this process, the vibration force field accelerates particle slippage under extrusion conditions. Under the action of extrusion and vibration, the gasified fine slag particles can be tightly arranged, compressing the skeleton / pore space where moisture exists, thereby achieving the goals of high dewatering efficiency, good dewatering effect, and low dewatering energy consumption. Detailed Implementation

[0020] The present invention will be further described in detail below with reference to specific embodiments.

[0021] All raw materials and reagents in the embodiments of this application were purchased from the market or prepared according to conventional methods known to those skilled in the art.

[0022] The specific surface area of ​​the coal gasification fine slag used in the following examples is 145 m². 2 / g, Loss on ignition (LOI) is 24%, Median particle size d of carbon content 50 It is 47μm.

[0023] In step (1) of the following embodiments, the ball mill speed is 100 r / min, the ball milling media accounts for 10 wt% of the mass of coal gasification fine slag, and the percentage of solid material in the slurry is 30%.

[0024] In step (3) of the following embodiment, the inner diameter of the dewatering mold is 150 mm, and the amount of vacuum filter cake in each feeding step (2) is 2 kg.

[0025] Comparative Example 1

[0026] A method for dewatering coal gasification fine slag involves directly using an extrusion dewatering device to dewater the coal gasification fine slag under the conditions of an extrusion strength of 10 MPa and an extrusion dewatering time of 1 min, to obtain a filter cake with a moisture content of 39%.

[0027] Comparative Example 2

[0028] A method for dewatering fine coal gasification slag involves using a vibration extrusion dewatering device to dewater the fine coal gasification slag under the conditions of extrusion strength of 10 MPa, vibration force of 2.3 MPa, vibration frequency of 23 Hz, and extrusion dewatering time of 1 min, to obtain a filter cake with a moisture content of 38%.

[0029] Example 1

[0030] A method for promoting the extrusion and dehydration of fine coal gasification slag using mechanical pore breaking and vibration force field empowerment includes the following steps:

[0031] (1) The coal gasification fine slag was ground using a wet ball mill. After grinding for 1 minute, a slurry was obtained. The median particle size d of the carbon-containing coal gasification fine slag after grinding was determined. 50 It is 19.3 μm;

[0032] (2) The slurry obtained in step (1) is pretreated by vacuum filtration to obtain a vacuum filter cake with a moisture content of 47%;

[0033] (3) The vacuum filter cake obtained in step (2) was subjected to vibration extrusion dewatering under the conditions of extrusion strength of 7 MPa, vibration force of 2.3 MPa, vibration frequency of 23 Hz, and extrusion dewatering time of 1 min to obtain a filter cake with a moisture content of 36%.

[0034] Example 2

[0035] A method for promoting the extrusion and dehydration of fine coal gasification slag using mechanical pore breaking and vibration force field empowerment includes the following steps:

[0036] (1) The coal gasification fine slag was ground using a wet ball mill. After grinding for 1 minute, a slurry was obtained. The median particle size d of the carbon-containing coal gasification fine slag after grinding was determined. 50 It is 19.3 μm;

[0037] (2) The slurry obtained in step (1) is pretreated by vacuum filtration to obtain a vacuum filter cake with a moisture content of 47%;

[0038] (3) The vacuum filter cake obtained in step (2) was subjected to vibration extrusion dewatering under the conditions of extrusion strength of 10 MPa, vibration force of 2.3 MPa, vibration frequency of 23 Hz, and extrusion dewatering time of 3 min to obtain a filter cake with a moisture content of 33%.

[0039] Example 3

[0040] A method for promoting the extrusion and dehydration of fine coal gasification slag using mechanical pore breaking and vibration force field empowerment includes the following steps:

[0041] (1) The coal gasification fine slag was ground using a wet ball mill. After grinding for 3 minutes, a slurry was obtained. The median particle size d of the carbon-containing coal gasification fine slag after grinding was determined. 50 It is 9.5μm;

[0042] (2) The slurry obtained in step (1) is pretreated by vacuum filtration to obtain a vacuum filter cake with a moisture content of 47%;

[0043] (3) The vacuum filter cake obtained in step (2) was subjected to vibration extrusion dewatering under the conditions of extrusion strength of 10 MPa, vibration force of 2.3 MPa, vibration frequency of 45 Hz and extrusion dewatering time of 3 min to obtain a filter cake with a moisture content of 31%.

[0044] Example 4

[0045] A method for promoting the extrusion and dehydration of fine coal gasification slag using mechanical pore breaking and vibration force field empowerment includes the following steps:

[0046] (1) The coal gasification fine slag was ground using a wet ball mill. After grinding for 6 minutes, a slurry was obtained. The median particle size d of the carbon-containing coal gasification fine slag after grinding was determined. 50 It is 6.8μm;

[0047] (2) The slurry obtained in step (1) is pretreated by vacuum filtration to obtain a vacuum filter cake with a moisture content of 47%;

[0048] (3) The vacuum filter cake obtained in step (2) was subjected to vibration extrusion dewatering under the conditions of extrusion strength of 10 MPa, vibration force of 2.3 MPa, vibration frequency of 45 Hz and extrusion dewatering time of 3 min to obtain a filter cake with a moisture content of 29%.

[0049] Example 5

[0050] A method for promoting the extrusion and dehydration of fine coal gasification slag using mechanical pore breaking and vibration force field empowerment includes the following steps:

[0051] (1) The coal gasification fine slag was ground using a wet ball mill. After grinding for 9 minutes, a slurry was obtained. The median particle size d of the carbon-containing coal gasification fine slag after grinding was determined. 50 It is 5.9 μm;

[0052] (2) The slurry obtained in step (1) is pretreated by vacuum filtration to obtain a vacuum filter cake with a moisture content of 47%;

[0053] (3) The vacuum filter cake obtained in step (2) was subjected to vibration extrusion dewatering under the conditions of extrusion strength of 10 MPa, vibration force of 2.3 MPa, vibration frequency of 45 Hz and extrusion dewatering time of 5 min to obtain a filter cake with a moisture content of 30%.

[0054] Based on the results of the above embodiments, it was found that introducing a vibration field during the extrusion dewatering process can improve the dewatering effect of gasification slag. Under the same dewatering conditions, the initial stage of grinding pretreatment of gasification slag helps to improve the dewatering effect of fine gasification slag. This is because the grinding process can effectively destroy the irregular shape and large pore structure of residual carbon in the fine gasification slag, thereby reducing the skeletal space between particles during the extrusion dewatering process, which is conducive to dewatering. Comparing Examples 4 and 5, it can be seen that excessive grinding leads to severe particle pulverization, significantly increasing the specific surface area of ​​the particles. At the same time, the water transport path during the dewatering process increases, limiting the effective removal of water. Therefore, the grinding process needs to strictly control the median particle size d of the carbon-containing fine coal gasification slag after grinding. 50 This means that grinding pretreatment is needed to improve the dehydration process, while over-grinding should be avoided to prevent it from limiting the dehydration effect. In addition, both grinding pretreatment of gasification slag and the introduction of a vibration field can effectively improve the dehydration effect, and the two have a synergistic promoting effect. This is because the irregular shape and rich pores on the surface of the gasification slag particles are destroyed by grinding pretreatment. During the extrusion dehydration process, the introduction of a vibration field can accelerate the sliding of the gasification slag particles after grinding, making the particles more compact and compressing the space for water storage, thereby improving the dehydration effect.

[0055] In summary, the grinding pretreatment in this invention helps improve the dewatering effect of gasification slag, but excessive grinding should be avoided to prevent it from hindering dewatering. In addition, the introduction of a vibration field into the extrusion dewatering process can improve the dewatering effect, and the introduction of the vibration field in combination with the grinding pretreatment will produce a more significant synergistic effect in promoting dewatering.

Claims

1. A method for promoting the extrusion and dehydration of fine coal gasification slag using mechanical pore breaking and vibration force field empowerment, characterized in that, Includes the following steps: (1) The coal gasification fine slag was ground using a wet ball mill. After grinding for 1-9 min, a slurry was obtained. The median particle size d of the carbon-containing coal gasification fine slag after grinding was determined. 50 The thickness is 5.9~19.3μm; (2) The slurry obtained in step (1) is pretreated by vacuum filtration to obtain a vacuum filter cake with a moisture content of 47-53%; (3) The vacuum filter cake obtained in step (2) is subjected to vibration extrusion dewatering device to obtain a filter cake with a moisture content of 29-36%; the extrusion strength is 7-10 MPa, the vibration force is 2.3 MPa and the vibration frequency is 23-45 Hz, and the extrusion dewatering time is 1-5 min.

2. The method for promoting the extrusion and dehydration of fine coal gasification slag using mechanical pore breaking and vibration force field empowerment as described in claim 1, characterized in that, In step (1), the median particle size d of the carbon-containing fine slag after 1 min of grinding is... 50 It is 19.3 μm.

3. The method for promoting the extrusion and dehydration of fine coal gasification slag using mechanical pore breaking and vibration force field empowerment as described in claim 1, characterized in that, In step (1), the median particle size d of the carbon-containing fine slag after 3 minutes of grinding is... 50 It is 9.5μm.

4. The method for promoting the extrusion and dehydration of fine coal gasification slag by mechanical pore breaking and vibration force field empowerment as described in claim 1, characterized in that, In step (1), the median particle size d of the carbon-containing fine slag after 6 minutes of grinding is... 50 It is 6.8μm.

5. The method for promoting the extrusion and dehydration of fine coal gasification slag by mechanical pore breaking and vibration force field empowerment according to claim 1, characterized in that, In step (1), the median particle size d of the carbon-containing fine slag after 9 minutes of grinding is... 50 It is 5.9 μm.

6. The method for promoting the extrusion and dewatering of fine coal gasification slag by mechanical pore breaking and vibration force field empowerment according to claim 1, characterized in that, In step (1), the ball mill speed is 100 r / min, the ball mill media accounts for 10 wt% of the mass of coal gasification fine slag, and the percentage of solid material in the slurry is 30%.

7. A method for promoting the extrusion and dewatering of fine coal gasification slag using mechanical pore breaking and vibration force field empowerment, as described in claim 1 or 2, characterized in that... In step (1), the specific surface area of ​​the coal gasification fine slag is 145 m². 2 / g, Loss on ignition (LOI) of 24%, Median particle size d of carbon content 50 It is 47μm.

8. A method for promoting the extrusion and dewatering of fine coal gasification slag using mechanical pore breaking and vibration force field empowerment, as described in claim 1 or 2, characterized in that... In step (3), the inner diameter of the dewatering mold is 150 mm, and the amount of vacuum filter cake fed each time is 2 kg in step (2).