Dehydration process method for strengthening gasification fine slag through mechanical hole breaking

Abstract

The invention relates to the technical field of gasification fine slag dehydration, and particularly discloses a dehydration process method for strengthening gasification fine slag through mechanical hole breaking, which comprises two steps of gasification fine slag mechanical grinding treatment and dehydration treatment, and the mechanical grinding treatment step is as follows: ore pulp with the gasification fine slag concentration of 20%-40% is put into a grinding machine for mechanical grinding hole breaking; the dehydration treatment comprises the following steps: preparing the ground gasified fine slag into gasified fine slag black water with the concentration of 8-20%, and carrying out vacuum dehydration to obtain a filter cake. After the gasification fine slag is mechanically ground and perforated, the dehydration lower limit of the gasification fine slag can be improved, and meanwhile, the hot drying dehydration efficiency can be improved. The method provided by the invention can effectively reduce the moisture of the gasified fine slag, improve the utilization value of the gasified fine slag, and reduce environmental pollution and economic cost caused by storage, transportation and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of gasification fine slag dehydration, and particularly relates to a mechanical pore-breaking enhanced dehydration process method for gasification fine slag. Background Technique

[0002] Coal gasification technology is one of the core processes in modern coal chemical industry, and is widely used in the production processes such as synthetic ammonia, methanol, dimethyl ether, synthetic oil, etc. However, a large amount of gasification fine slag with extremely high water content is generated during the coal gasification process. Its water content is usually between 85% - 95%, and the water content is still as high as 55% after vacuum filtration.

[0003] The treatment of these gasification fine slags has always been a bottleneck problem restricting the sustainable development of the coal chemical industry. The developed pore structure of the gasification fine slag provides a rich habitat space for water. And due to the complexity of some pore structures, the dehydration difficulty is greatly increased. Directly configuring the gasification fine slag into gasification fine slag black water for vacuum filtration dehydration has limited dehydration capacity, and the water content in the gasification fine slag filter cake is still very high; the gasification fine slag has a high porosity, and the complex pore structure provides a rich space for water storage. Due to the complexity of the pore structure, the water in the pores cannot be removed by vacuum filtration; especially, the large pores in the large particles are rich and the water content in the large pores is high. Therefore, developing a new gasification fine slag dehydration method is of great significance for the resource utilization of gasification fine slag. Summary of the Invention

[0004] The purpose of the present invention is to provide a mechanical pore-breaking enhanced dehydration process method for gasification fine slag. This method destroys the pore structure of gasification fine slag particles through simple mechanical pretreatment, promotes the release of pore water, weakens the water-holding capacity of gasification fine slag particles, and thus improves the water removal ability of gasification fine slag.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A mechanical pore-breaking enhanced dehydration process method for gasification fine slag, comprising the following steps:

[0007] Obtain a slurry to be treated with a concentration of 20% - 40%;

[0008] Grind and break the pores of the slurry to be treated to obtain pore-broken gasification fine slag;

[0009] Configure the pore-broken gasification fine slag into gasification fine slag black water with a concentration of 8% - 20%;

[0010] Dehydrate the gasification fine slag black water by using a vacuum filtration device to obtain a gasification fine slag filter cake; the vacuum degree is in the range of 0.07 - 0.09 MPa.

[0011] Preferably, the pore-breaking method is wet grinding.

[0012] Preferably, the pulp to be treated is fed into the mill by a feed pump; the pulp to be treated is subjected to wet mechanical grinding to break pores; the gasification fine slag black water is transported to a vacuum filtration device by a feed pump; and the filter cake is conveyed to a product bin by a belt.

[0013] Preferably, the vacuum filtration device consists of a ceramic membrane filter plate, a circulating water vacuum pump, a buffer bottle, and an air compressor, and the filtration time is 20 s under the liquid and 25 s above the liquid.

[0014] Preferably, the water content of the gasification fine slag filter cake is measured by a fully automatic fast water meter at a test temperature of 105 °C.

[0015] The present invention uses mechanical grinding to break the gasification fine slag particles. The rod mill method preferentially breaks large particles, and large pores in the particles are opened. The ball mill can further break fine particles. The results of the examples show that after pore breaking, the particle size of the gasification fine slag decreases, the porosity decreases, and the water content of the filter cake decreases; after the gasification fine slag is mechanically ground to break pores, the water content of the obtained gasification fine slag filter cake decreases by 5-10 percentage points compared with that of the unbroken gasification fine slag filter cake.

[0016] In summary, the method provided by the present invention improves the lower limit of dehydration of gasification fine slag, has a high dehydration rate, can effectively reduce the moisture of gasification fine slag, improve the utilization value of gasification fine slag, and reduce environmental pollution and economic costs caused by storage, transportation, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a process flow chart of the present invention.

[0018] Figure 2 is a scanning electron microscope image of the gasification fine slag in Example 3; (a) is the SEM image of the original slag, and (b) and (c) represent the SEM images of the gasification fine slag at different positions after pore breaking.

[0019] Figure 3 is the pore size distribution diagram (a) and the spatial distribution size of the filter cake moisture (b) of the gasification fine slag before and after pore breaking in Example 3. DETAILED DESCRIPTION OF THE INVENTION

[0020] The present invention provides a mechanical pore-breaking enhanced dehydration process method for gasification fine slag, including the following steps:

[0021] Obtain the pulp to be treated;

[0022] After grinding the prepared slurry for a period of time, obtain pore-broken gasification fine slag;

[0023] Configure the pore-broken gasification fine slag into gasification fine slag black water;

[0024] Dehydrate the gasification fine slag black water to obtain a gasification fine slag filter cake;

[0025] The water content of the gasified fine slag filter cake is measured by a fully automatic fast water meter at a test temperature of 105 °C.

[0026] In the present invention, the slurry to be treated is obtained by concentrating the black water in the flocculation tank of the gasification plant; the slurry is fed into a grinder by a feed pump, and after grinding, perforated gasified fine slag is obtained; the perforated gasified fine slag is fed into a stirring tank by a feed pump and configured into gasified fine slag black water in proportion; the concentration of the gasified fine slag black water is 8%-20%.

[0027] In the present invention, the grinder can be a rod mill, a ball mill or other types of mills; in the present invention, the selection of the mill needs to follow the principle that mild grinding method is used for finer gasified fine slag and rapid grinding method is used for coarser gasified fine slag to ensure that the gasified fine slag can be perforated while avoiding over-grinding; the grinding efficiency of using a rod mill for coarser slag is low, and using a ball mill for finer slag is likely to cause capillary phenomenon due to over-grinding, resulting in poor dehydration effect; taking the examples in the present invention as a reference, preferably, when D50≥90μm, a ball mill is selected, and when D50≤90μm, a rod mill is selected;

[0028] The concentration of the slurry is 20%-40%. Taking the examples in the present invention as a reference, more preferably, when D50≥60μm, the concentration is 20-25%, and when D50≤35μm, the concentration is 35-40%.

[0029] In the present invention, the gasified fine slag filter cake is obtained by a vacuum filter; the water content of the perforated gasified fine slag filter cake is measured by a fast water meter, and the average value is taken after measuring 5 times for each sample; the water content of the perforated gasified fine slag is reduced by 5-10 percentage points compared with the water content of the original gasified fine slag filter cake, preferably, reduced by 8-10 percentage points.

[0030] Example 1

[0031] As Figure 1 shown, a mechanical perforation enhanced dehydration process method for gasified fine slag. The raw material used in this example is black water with a concentration of 10% of rich carbon gasified fine slag raw slag, and the water content of its vacuum filtration filter cake is 56.44%; it includes the following steps:

[0032] The gasified fine slag is configured into a slurry with a concentration of 30% and put into a stirring ball mill. After grinding at a speed of 300 Hz for 3 minutes, perforated gasified fine slag is obtained; the perforated gasified fine slag is configured into gasified fine slag black water with a concentration of 10%; the gasified fine slag black water is passed through a ceramic vacuum filter to obtain a gasified fine slag filter cake, the vacuum degree is in the range of 0.07-0.09 MPa, and the filtration time is 20 s under the liquid and 25 s above the liquid; the water content of the perforated gasified fine slag filter cake is measured to be 47.87%, and compared with the original gasified fine slag filter cake, the water content is reduced by 8.57%.

[0033] Example 2

[0034] As Figure 1 shown, a dehydration process method for mechanically perforated and strengthened gasification fine slag. The raw material used in this embodiment is black water with a concentration of 20% of rich carbon gasification fine slag raw slag, and the water content of its vacuum filtration filter cake is 53.60%; it includes the following steps:

[0035] Configure the gasification fine slag into a slurry with a concentration of 30% and put it into a stirred ball mill. After grinding at a speed of 300 Hz for 3 minutes, perforated gasification fine slag is obtained; configure the perforated gasification fine slag into gasification fine slag black water with a concentration of 15%; pass the gasification fine slag black water through a ceramic vacuum filter to obtain a gasification fine slag filter cake, the vacuum degree is in the range of 0.07 - 0.09 MPa, the filtration time is 20 s under the liquid level and 25 s above the liquid level; it is measured that the water content of the perforated gasification fine slag filter cake is 45.32%, compared with the original gasification fine slag filter cake, the water content decreases by 8.28%.

[0036] Example 3

[0037] As Figure 1 shown, a dehydration process method for mechanically perforated and strengthened gasification fine slag. The black water with a concentration of 20% of the gasification fine slag raw slag used in this embodiment has a water content of 46.00% in its vacuum filtration filter cake; it includes the following steps:

[0038] Configure the gasification fine slag into a slurry with a concentration of 40% and put it into a rod mill. After grinding at a speed of 80 rad / min for 18 minutes, perforated gasification fine slag is obtained; configure the perforated gasification fine slag into gasification fine slag black water with a concentration of 20%; pass the gasification fine slag black water through a ceramic vacuum filter to obtain a gasification fine slag filter cake, the vacuum degree is in the range of 0.07 - 0.09 MPa, the filtration time is 20 s under the liquid level and 25 s above the liquid level; it is measured that the water content of the perforated gasification fine slag filter cake is 40.39%, compared with the original gasification fine slag filter cake, the water content decreases by 5.61%.

[0039] As Figure 2 shown, it can be seen in the figure that there are obvious particle fracture surfaces after perforation, and the pores at the fracture are exposed; Figure 3 a The pore diameter of the perforated gasification fine slag decreases and the porosity decreases; as Figure 3 b, the size of the spatial distribution of the filter cake moisture of the perforated gasification fine slag decreases; after perforation, the pore water inside the particles is released, and the water in the pores is converted into water outside the pores and is more easily removed by vacuum dehydration, and the lower limit of vacuum dehydration of the gasification fine slag increases; after perforation, the internal moisture migration path of the particles is shortened, the moisture removal rate increases, which is beneficial to accelerating the thermal drying rate and reducing the drying energy consumption.

[0040] Example 4

[0041] As Figure 1As shown, a dehydration process method for mechanically perforating and strengthening the gasification fine slag. In this embodiment, the original slag concentration of the gasification fine slag is 10% black water, and the water content of its vacuum filtration cake is 66.77%. The method includes the following steps:

[0042] Put the slurry with a gasification fine slag concentration of 20% into a rod mill and grind it at a speed of 80 rad / min for 12 min to obtain perforated gasification fine slag; configure the perforated gasification fine slag into gasification fine slag black water with a concentration of 10%; pass the gasification fine slag black water through a ceramic vacuum filter to obtain a gasification fine slag filter cake, with the vacuum degree in the range of 0.07 - 0.09 MPa and the filtration time of 20 s under the liquid and 25 s above the liquid; measure that the water content of the perforated gasification fine slag filter cake is 61.59%, and compared with the original gasification fine slag filter cake, the water content drops by 5.18%.

[0043] Example 5

[0044] As Figure 1 As shown, a dehydration process method for mechanically perforating and strengthening the gasification fine slag. In this embodiment, the original slag concentration of the gasification fine slag is 10% black water, and the water content of its vacuum filtration cake is 58.87%. The method includes the following steps:

[0045] Put the slurry with a gasification fine slag concentration of 20% into a rod mill and grind it at a speed of 80 rad / min for 12 min to obtain perforated gasification fine slag; configure the perforated gasification fine slag into gasification fine slag black water with a concentration of 10%; pass the gasification fine slag black water through a ceramic vacuum filter to obtain a gasification fine slag filter cake, with the vacuum degree in the range of 0.07 - 0.09 MPa and the filtration time of 20 s under the liquid and 25 s above the liquid; measure that the water content of the perforated gasification fine slag filter cake is 53.81%, and compared with the original gasification fine slag filter cake, the water content drops by 5.06%.

[0046] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art, without departing from the principle of the present invention, makes equivalent substitutions or changes according to the technical solution and inventive concept of the present invention, and should be covered by the protection scope of the present invention.

Claims

1. A dehydration process method for mechanically perforating and strengthening the dehydration of fine slag from gasification, characterized in that, Including the following steps: Obtain the pulp to be treated with a concentration of 20%-40%; After grinding and perforating the pulp to be treated, obtain perforated gasification fine slag; Configure the perforated gasification fine slag into gasification fine slag black water with a concentration of 8%-20%; Dehydrate the gasification fine slag black water by using a vacuum filtration device to obtain a gasification fine slag filter cake; the vacuum degree is within the range of 0.07-0.09 MPa.

2. The dehydration process method for mechanically perforating and strengthening the gasification fine slag according to claim 1, wherein: The perforation method is wet grinding.

3. A dehydration process method for mechanically perforating and strengthening the gasification fine slag according to claim 1, characterized in that: The pulp to be treated is fed into the mill by a feed pump; the pulp to be treated is perforated by wet mechanical grinding; the gasification fine slag black water is transported to the vacuum filtration device by a feed pump; the filter cake is conveyed to the product bin by a belt.

4. A dehydration process method for mechanically perforating and strengthening the gasification fine slag according to claim 1, characterized in that: The vacuum filtration device consists of a ceramic membrane filter plate, a circulating water vacuum pump, a buffer bottle, and an air compressor, and the filtration time is 20 s under the liquid and 25 s above the liquid.

5. A dehydration process method for mechanically perforating and strengthening the gasification fine slag according to claim 1, characterized in that: Measure the water content of the gasification fine slag filter cake by using a fully automatic fast water meter, and the test temperature is 105°C.

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