Coal gasification fine slag charcoal ash separation and enrichment process

Abstract

The invention discloses a coal gasification fine slag charcoal ash separation and enrichment process which comprises the following steps: S1, pre-enrichment: enabling coal gasification fine slag to pass through a filter sieve to obtain a carbon residue pre-enriched product and an inorganic component pre-enriched product; s2, carbon ash dissociation: respectively carrying out carbon ash dissociation treatment on the carbon residue pre-enriched product and the inorganic component pre-enriched product in the step S1; and S3, charcoal-ash separation: feeding a charcoal-ash dissociation material of the carbon residue pre-enriched product in the step S2 into an airflow classification system by adopting a screw conveyor, or feeding a charcoal-ash dissociation material of the inorganic component pre-enriched product in the step S2 into the airflow classification system. The coal gasification fine slag carbon residues and inorganic components are pre-enriched by adopting the filter sieve, and then the carbon residues and the inorganic components in the coal gasification fine slag are efficiently enriched by respectively adopting a rod mill crushing technology, an airflow crushing technology and an airflow grading technology, so that the problems of low separation efficiency and high economic cost in the prior art are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of solid waste separation and utilization, and particularly to a process for separating and enriching carbon ash from coal gasification fine slag. Background Art

[0002] In coal gasification fine slag, residual carbon and inorganic components are mutually molten and coated, resulting in low direct utilization efficiency of coal gasification fine slag; the inorganic minerals embedded in the residual carbon in coal gasification fine slag will affect the porosity and specific surface area of coal gasification fine slag. Currently, when preparing mesoporous materials from coal gasification fine slag, acid treatment is required for coal gasification fine slag to remove inorganic minerals; the residual carbon in coal gasification fine slag will limit the cementitious reaction of coal gasification fine slag with cement or lime, affecting the strength of cement and mortar; therefore, separating and enriching residual carbon and inorganic components in coal gasification fine slag is a necessary way for the resource utilization of coal gasification fine slag.

[0003] Currently, the separation methods of coal gasification fine slag mainly include screening method, gravity separation method, flotation method and combined process. The screening method is simple in operation and low in cost, but has poor applicability and low separation accuracy for fine-grained materials; the gravity separation method is only applicable to coarse particle sizes, and the separation effect becomes worse as the particle size of the material decreases; the flotation method has high separation efficiency and wide applicability, but has a large consumption of reagents and high economic cost; the combined process is relatively complex and difficult to be popularized on a large scale; therefore, there is an urgent need to develop a process for separating and enriching carbon-ash from coal gasification fine slag with simple process, strong applicability, low separation cost and high separation efficiency. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies in the above prior art, and provide a process for separating and enriching carbon ash from coal gasification fine slag. A filter screen is used to pre-enrich the residual carbon and inorganic components of coal gasification fine slag, and then rod milling and airflow crushing technologies are respectively adopted. The mechanical property differences between the residual carbon and inorganic components are utilized to achieve full dissociation of the residual carbon and inorganic components. Then, an airflow classification technology is adopted, and the particle size differences between the residual carbon and inorganic components are utilized to separate the residual carbon and inorganic components, so that the residual carbon and inorganic components in coal gasification fine slag are efficiently enriched, and the problems of low separation efficiency and high economic cost in the prior art are solved.

[0005] To achieve the above object, the technical solution adopted by the present invention is: a process for separating, enriching and concentrating carbon ash from fine slag of coal gasification, comprising the following steps: Step S1, pre-enrichment: the fine slag of coal gasification passes through a filter screen to obtain a pre-enriched product of residual carbon and a pre-enriched product of inorganic components; Step S2, carbon ash dissociation: the pre-enriched product of residual carbon and the pre-enriched product of inorganic components in Step S1 are respectively subjected to carbon ash dissociation treatment; Step S3, carbon ash separation: the carbon ash dissociation material of the pre-enriched product of residual carbon in Step S2 is fed into an air classification system by a screw conveyor to obtain a first-stage product of residual carbon, a second-stage product of residual carbon and a third-stage product of residual carbon, or the carbon ash dissociation material of the pre-enriched product of inorganic components in Step S2 is fed into the air classification system to obtain a first-stage product of inorganic components, a second-stage product of inorganic components and a third-stage product of inorganic components.

[0006] Preferably, the screen hole of the filter screen in Step S1 is 0.074 mm.

[0007] Preferably, the carbon ash dissociation treatment includes grinding dissociation treatment and air flow crushing dissociation treatment. The pre-enriched product of residual carbon is subjected to grinding dissociation treatment, and the pre-enriched product of inorganic components is subjected to air flow crushing dissociation treatment.

[0008] Preferably, the grinding dissociation treatment uses a ball mill or a rod mill, and the air flow crushing dissociation treatment uses a crushing chamber.

[0009] Preferably, the crushing duration of the grinding dissociation treatment is 10 - 40 min.

[0010] Preferably, the third-stage product of residual carbon is a concentrated product of residual carbon, and the first-stage product of inorganic components is a concentrated product of inorganic components.

[0011] Preferably, the feeding speed of the screw conveyor is 150 g / min.

[0012] Preferably, the air flow impact crushing pressure of the crushing chamber is 0.3 - 0.7 Mpa.

[0013] Preferably, the air classification system includes a first classifier and a second classifier, the first classifier and the second classifier are connected in series, the working frequency of the first classifier is 30 - 40 Hz, and the working frequency of the second classifier is 100 - 120 Hz.

[0014] Preferably, both the first classifier and the second classifier adopt a cage-type classifier.

[0015] The present invention has the following advantages compared with the prior art:

[0016] 1. The present invention uses a filtering sieve to achieve preliminary enrichment of the residual carbon and inorganic components in the fine slag of coal gasification, and then respectively adopts rod milling and air pulverization technologies to fully dissociate the residual carbon and inorganic components by utilizing the mechanical property differences between the residual carbon and inorganic components. Subsequently, an air classification technology is used to separate the residual carbon and inorganic components by utilizing the particle size differences between the residual carbon and inorganic components, enabling efficient enrichment of the residual carbon and inorganic components in the fine slag of coal gasification, and solving the problems of low separation efficiency and high economic cost in the prior art.

[0017] 2. By adjusting the rod milling time, pulverization pressure, and air classification parameters, the present invention achieves the predetermined enrichment effect of the residual carbon and inorganic components in the fine slag of coal gasification, and solves the problems of difficult dehydration, poor applicability, and high reagent cost in the existing gravity / flotation technologies for the fine slag of coal gasification.

[0018] 3. The present invention utilizes the screening of a filtering sieve to achieve preliminary enrichment of the residual carbon and inorganic components in the fine slag of coal gasification, effectively reducing the processing volume of rod milling and air pulverization, reducing energy consumption, and improving the enrichment efficiency.

[0019] 4. The present invention is a dry separation technology, which does not need to consider the drying and dehydration links required by traditional gravity separation and flotation technologies. The process is simpler and more suitable for arid and water-scarce areas in the western region.

[0020] The following further describes the present invention in detail through the drawings and embodiments. Description of the Drawings

[0021] Figure 1 is the process flow diagram of the carbon-ash separation and enrichment of the fine slag of coal gasification according to the present invention;

[0022] Figure 2 are the microscopic characteristics of each classified product of the preliminary enrichment product of the residual carbon according to the present invention;

[0023] Figure 3 are the microscopic characteristics of each classified product of the preliminary enrichment product of the inorganic components according to the present invention. Detailed Embodiments

[0024] Example 1

[0025] First, analyze the physical and chemical properties of the fine slag of coal gasification. Table 1 shows the results of the proximate analysis and elemental analysis of the fine slag of coal gasification.

[0026] Table 1

[0027]

[0028] As Figure 1 shown, the carbon-ash separation and enrichment process of the fine slag of coal gasification includes the following steps: Step S1. Preliminary enrichment: The fine slag of coal gasification passes through a filtering sieve to obtain a preliminary enrichment product of residual carbon and a preliminary enrichment product of inorganic components;

[0029] The sieve aperture of the filter sieve in step S1 is 0.074 mm.

[0030] According to experimental statistics, the ash content of the -0.074 mm particle size sample in the fine slag of coal gasification is generally high, while the ash content of the +0.074 mm particle size sample is generally low. Therefore, a filter sieve with a sieve aperture of 0.074 mm is selected. After the fine slag of coal gasification is screened by the 0.074 mm filter sieve, a pre-enriched product of residual carbon and a pre-enriched product of inorganic components are obtained. The particle size of the pre-enriched product of residual carbon is +0.074 mm, and the particle size of the pre-enriched product of inorganic components is -0.074 mm. The content of inorganic components (ash) in the pre-enriched product of residual carbon and the pre-enriched product of inorganic components is shown in Table 2.

[0031] Table 2

[0032] Sample Name Ash Content w / % Pre-enriched Product of Residual Carbon 53.25 Pre-enriched Product of Inorganic Components 80.69

[0033] Step S2, carbon-ash dissociation: The pre-enriched product of residual carbon and the pre-enriched product of inorganic components in step S1 are respectively subjected to carbon-ash dissociation treatment;

[0034] The carbon-ash dissociation treatment includes grinding dissociation treatment and air flow crushing dissociation treatment. The pre-enriched product of residual carbon is treated by grinding dissociation treatment, and the pre-enriched product of inorganic components is treated by air flow crushing dissociation treatment.

[0035] The grinding dissociation treatment uses a ball mill or a rod mill, and the air flow crushing dissociation treatment uses a crushing chamber.

[0036] The crushing duration of the grinding dissociation treatment is 10 - 40 min.

[0037] The air flow impact crushing pressure of the crushing chamber is 0.3 - 0.7 Mpa.

[0038] The ash content of the pre-enriched product of residual carbon in the fine slag of coal gasification is 53.25%. In this embodiment, a rod mill is used for crushing for 30 min to fully dissociate the residual carbon and inorganic components in the pre-enriched product of residual carbon.

[0039] The ash content of the pre-enriched product of residual carbon in the fine slag of coal gasification is 53.25%. In another possible embodiment, air flow impact crushing dissociation is carried out in a crushing chamber, and the air flow impact crushing pressure of the crushing chamber is 0.3 Mpa. Under the impact of high-pressure air flow, the pre-enriched product of residual carbon undergoes crushing dissociation, so that the residual carbon and inorganic components in the pre-enriched product of residual carbon are fully dissociated.

[0040] The ash content of the inorganic component pre-enrichment product in the coal gasification fine slag is 80.69%. In this embodiment, an air impact pulverization and dissociation is carried out on the inorganic component pre-enrichment product using a pulverization chamber, so that the residual carbon and inorganic components in the inorganic component pre-enrichment product are fully dissociated; the air impact pulverization pressure of the pulverization chamber is 0.3 Mpa. High-pressure air flows out from the high-speed nozzles of the pulverization chamber, and under the impact of the high-pressure air flow, the inorganic component pre-enrichment product undergoes pulverization and dissociation, so that the residual carbon and inorganic components in the inorganic component pre-enrichment product are fully dissociated.

[0041] The ash content of the inorganic component pre-enrichment product in the coal gasification fine slag is 80.69%. In another possible embodiment, a rod mill is used for pulverization for 30 min to fully dissociate the residual carbon and inorganic components in the inorganic component pre-enrichment product.

[0042] Step S3, carbon-ash separation: Use a screw conveyor to send the carbon-ash dissociation material of the residual carbon pre-enrichment product in step S2 into an air classification system to obtain a primary residual carbon product, a secondary residual carbon product, and a tertiary residual carbon product;

[0043] The feeding speed of the screw conveyor is 150 g / min.

[0044] The tertiary residual carbon product is a residual carbon enrichment product, and the primary inorganic component product is an inorganic component enrichment product.

[0045] The air classification system includes a first classifier and a second classifier, which are connected in series. The operating frequency of the first classifier is 30 - 40 Hz, and the operating frequency of the second classifier is 100 - 120 Hz.

[0046] The carbon-ash dissociation material of the residual carbon pre-enrichment product after pulverization and dissociation using a rod mill is sent into the pulverization chamber through a screw conveyor at a feeding rate of 150 g / min. The pulverization chamber conveys the carbon-ash dissociation material of the residual carbon pre-enrichment product into the air classification system at a pressure of 0.1 MPa. Under the action of the air flow, it enters the first classifier and the second classifier in sequence. The first classifier classifies the carbon-ash dissociation material at an operating frequency of 40 Hz. The coarse particle material is discharged from the bottom of the first classifier as the primary residual carbon product. The fine particles in the first classifier enter the second classifier after passing through the first classifier. The second classifier classifies the fine particles entering the second classifier at an operating frequency of 120 Hz. The coarser particles among the fine particles of the second classifier are discharged from the bottom of the second classifier as the secondary residual carbon product. The finer particles among the fine particles of the second classifier are discharged from the upper part of the second classifier as the tertiary residual carbon product; Therefore, the primary residual carbon product is the coarse particles that did not pass through the first classifier, the secondary residual carbon product is the particles that passed through the first classifier but did not pass through the second classifier, and the tertiary residual carbon product is the fine particles that passed through the second classifier.

[0047] In another possible embodiment, different from the above embodiment, the screw conveyor conveys the pre-enriched product of residual carbon to the crushing chamber for air impact crushing and dissociation.

[0048] After crushing and dissociating with a rod mill and crushing and dissociating in the crushing chamber by air impact, the yields and ash contents of the first-stage residual carbon product, the second-stage residual carbon product, and the third-stage residual carbon product obtained respectively are analyzed by an air classification system. It can be obtained that the third-stage residual carbon product is the residual carbon enriched product, and the analysis results are shown in Table 3.

[0049] Table 3

[0050] Rod Mill - Classification First-grade Product of Residual Carbon Second-grade Product of Residual Carbon Third-grade Product of Residual Carbon Yield w / % 39.73 14.20 46.07 Ash Content w / % 61.38 51.17 35.51 Airflow Pulverization - Classification First-grade Product of Residual Carbon Second-grade Product of Residual Carbon Third-grade Product of Residual Carbon Yield w / % 38.24 20.18 41.58 Ash Content w / % 59.08 50.27 38.62

[0051] As can be seen from Table 3, the yield of the third-stage residual carbon product after crushing and dissociating with a rod mill is higher than that of the third-stage residual carbon product after crushing and dissociating in the crushing chamber by air impact, and the ash content of the third-stage residual carbon product after crushing and dissociating with a rod mill is lower than that of the third-stage residual carbon product after crushing and dissociating in the crushing chamber by air impact. Therefore, in this application, a rod mill is used to dissociate carbon and ash of the pre-enriched product of residual carbon.

[0052] As Figure 2 shown, based on the microscopic characteristics of the first-stage residual carbon product, the second-stage residual carbon product, and the third-stage residual carbon product, it can be concluded that the vitreous body is mainly concentrated in the first-stage residual carbon product with less symbiotic situation, and the number of monomeric flaky residual carbon in the third-stage residual carbon product is larger; the areas of amorphous vitreous bodies in the first-stage residual carbon product, the second-stage residual carbon product, and the third-stage residual carbon product are statistically analyzed, and the results are shown in Table 4. The proportion of the area of amorphous vitreous body in the third-stage residual carbon product is the lowest, which is consistent with the ash distribution trend of the air classification product, further verifying that the third-stage residual carbon product is the residual carbon enriched product.

[0053] Table 4

[0054] First-grade Product of Residual Carbon Second-grade Product of Residual Carbon Third-grade Product of Residual Carbon <![CDATA[Total amorphous vitreous area um 2 > 946.28 427.64 126.39 Proportion of Amorphous Vitreous Area % 35.33 16.27 5.07

[0055] After classification by the first classifier and the second classifier, the particle size of the third-stage residual carbon product is finer than that of the first-stage residual carbon product and the second-stage residual carbon product. From the above experiments, it can be seen that the ash content of the third-stage residual carbon product is lower than that of the first-stage residual carbon product and the second-stage residual carbon product. Then, the carbon content of the third-stage residual carbon product is higher than that of the first-stage residual carbon product and the second-stage residual carbon product. Therefore, the third-stage residual carbon product is the residual carbon enriched product.

[0056] Feed the carbon-ash dissociation material of the pre-enriched product of inorganic components in step S2 into the air classification system to obtain the first-stage inorganic component product, the second-stage inorganic component product, and the third-stage inorganic component product.

[0057] Feed the inorganic component pre-enrichment product into the crushing chamber through a screw conveyor at a feeding rate of 150 g / min, crush and dissociate the inorganic component pre-enrichment product in the crushing chamber under a pressure of 0.5 MPa, and feed the dissociated inorganic component pre-enrichment product into the air classification system. Under the action of the air flow, it enters the first classifier and the second classifier in sequence. The first classifier classifies the dissociated inorganic component pre-enrichment product at a working frequency of 35 Hz. The coarse particle material is discharged from the bottom of the first classifier as the first-grade inorganic component product. The fine particles in the first classifier enter the second classifier after passing through the first classifier. The second classifier classifies the fine particles entering the second classifier at a working frequency of 110 Hz. The coarser particles in the fine particles of the second classifier are discharged from the bottom of the second classifier as the second-grade inorganic component product, and the finer particles in the fine particles of the second classifier are discharged from the upper part of the second classifier as the third-grade inorganic component product; Therefore, the first-grade inorganic component product is the coarse particles that have not passed through the first classifier, the second-grade inorganic component product is the particles that have passed through the first classifier but not through the second classifier, and the third-grade inorganic component product is the fine particles that have passed through the second classifier.

[0058] In another possible embodiment, different from the above embodiment, the inorganic component pre-enrichment product crushed and dissociated by a rod mill is fed into the crushing chamber through a screw conveyor at a feeding rate of 150 g / min, and the crushing chamber feeds the inorganic component carbon ash dissociation material into the air classification system under a pressure of 0.1 MPa.

[0059] After the inorganic component pre-enrichment product is crushed and dissociated by air crushing and a rod mill, and then the yields and ash contents of the obtained first-grade inorganic component product, second-grade inorganic component product, and third-grade inorganic component product are analyzed through the air classification system, it can be obtained that the first-grade inorganic component product is the inorganic component enrichment product, and the analysis results are shown in Table 5.

[0060] Table 5

[0061]

[0062]

[0063] As can be seen from Table 5, the yield of the first-grade inorganic component product after being crushed and dissociated by air crushing is higher than that of the first-grade inorganic component product after being crushed and dissociated by a rod mill, and the ash content of the first-grade inorganic component product after being crushed and dissociated by air crushing is higher than that of the first-grade inorganic component product after being crushed and dissociated by a rod mill. Therefore, this application uses air crushing to dissociate the carbon ash of the inorganic component pre-enrichment product.

[0064] Such as Figure 3As shown in the figure, based on the microscopic characteristics of the primary inorganic component product, the secondary inorganic component product, and the tertiary inorganic component product, it can be seen that the glassy inorganic substances are mainly concentrated in the primary inorganic component product, and the flaky and reticular residual carbon are mainly concentrated in the tertiary inorganic component product. The amorphous vitreous area in the primary inorganic component product, the secondary inorganic component product, and the tertiary inorganic component product was statistically analyzed, and the results are shown in Table 6. The proportion of the amorphous vitreous area in the primary inorganic component product is the highest, which is consistent with the ash distribution trend of the air classification product, further verifying that the primary inorganic component product is the inorganic component enrichment product.

[0065] Table 6

[0066]

[0067] The particle size of the primary inorganic component product is larger than that of the secondary inorganic component product and the tertiary inorganic component product. From the above experiments, it can be seen that the ash content of the primary inorganic component product is higher than that of the secondary inorganic component product and the tertiary inorganic component product. Therefore, the primary inorganic component product is the inorganic component enrichment product.

[0068] Both the first classifier and the second classifier adopt cage-type classifiers.

[0069] The first classifier and the second classifier classify the materials by adjusting the rotation speed of the classification wheel. By adjusting the working frequencies of the first classifier and the second classifier, the purpose of adjusting the classification particle size can be achieved. The bottom outlet of the first classifier outputs the primary product, and the materials with particle sizes smaller than the primary product are transferred to the second classifier after passing through the first classifier. The working frequency of the second classifier is greater than that of the first classifier and is used to classify particles with smaller particle sizes. The bottom outlet of the second classifier outputs the secondary product, and the materials with particle sizes smaller than the secondary product pass through the second classifier to obtain the tertiary product.

[0070] The above description is only a preferred embodiment of the present invention and does not impose any limitations on the present invention. Any simple modifications, changes, and equivalent structural transformations made to the above embodiments based on the technical essence of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A process for separation and enrichment of coal gasification fine slag and carbon ash, characterized in that: The following steps are involved: Step S1, pre-enrichment: the coal gasification fine slag is filtered and sieved to obtain a residual carbon pre-enrichment product and an inorganic component pre-enrichment product; Step S2, carbon ash dissociation: the carbon residue pre-enrichment product and the inorganic component pre-enrichment product in step S1 are subjected to carbon ash dissociation treatment respectively; Step S3, charcoal ash separation: Use a screw conveyor to send the charcoal ash dissociated material of the residual carbon pre-enrichment product in step S2 into an airflow classification system to obtain a residual carbon primary product, a residual carbon secondary product and a residual carbon tertiary product, or send the charcoal ash dissociated material of the inorganic component pre-enrichment product in step S2 into an airflow classification system to obtain an inorganic component primary product, an inorganic component secondary product and an inorganic component tertiary product.

2. A coal gasification fine slag and ash separation and enrichment process according to claim 1, characterized in that: The mesh size of the filter screen in step S1 is 0.074 mm.

3. A coal gasification fine slag and ash separation and enrichment process according to claim 1, characterized in that: The carbon ash dissociation treatment includes grinding dissociation treatment and air flow pulverization dissociation treatment. The residual carbon pre-enrichment product adopts grinding dissociation treatment, and the inorganic component pre-enrichment product adopts air flow pulverization dissociation treatment.

4. A coal gasification fine slag and ash separation and enrichment process according to claim 3, characterized in that: The grinding and dissociation treatment adopts a ball mill or a rod mill, and the air flow pulverization and dissociation treatment adopts a pulverization chamber to perform air flow impact pulverization.

5. A coal gasification fine slag and ash separation and enrichment process according to claim 3, characterized in that: The grinding and dissociation process is carried out for a pulverizing time of 10-40 minutes.

6. A coal gasification fine slag and ash separation and enrichment process according to claim 1, characterized in that: The tertiary carbon residue product is a carbon residue enriched product, and the primary inorganic component product is an inorganic component enriched product.

7. A coal gasification fine slag and ash separation and enrichment process according to claim 1, characterized in that: The feeding speed of the screw conveyor is 150 g / min.

8. A coal gasification fine slag and ash separation and enrichment process according to claim 4, characterized in that: The airflow impact crushing pressure of the crushing chamber is 0.3-0.7Mpa.

9. A coal gasification fine slag and ash separation and enrichment process according to claim 1, characterized in that: The airflow classification system comprises a first classifier and a second classifier, wherein the first classifier and the second classifier are connected in series, the working frequency of the first classifier is 30-40 Hz, and the working frequency of the second classifier is 100-120 Hz.

10. A coal gasification fine slag and ash separation and enrichment process according to claim 9, characterized in that: The first classifier and the second classifier are both squirrel cage classifiers.

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