Graded and quality-divided utilization device for coal gasification slag

Abstract

The utility model discloses a grading and quality-grading utilization device for coal gasification slag, and belongs to the field of solid waste resource utilization. The device comprises a screening and roller grinding unit used for screening and high-pressure roller grinding of the coal gasification coarse slag; the drying and grading unit is used for mixing, drying and grading the materials; the iron removal unit is used for removing iron from the low-carbon material; and the grinding unit is used for continuously and sectionally grinding the iron-removed material. According to the device disclosed by the utility model, carbon-rich materials, iron-rich materials and pozzolanic mixed materials of which the specific surface area is greater than or equal to 550m < 2 > / kg and the 28d activity index is greater than or equal to 75% are respectively obtained through the treatment of working procedures such as high-pressure roller milling, drying and grading, efficient iron removal and continuous sectional grinding, so that the grading and grading utilization of the coal gasification coarse slag and fine slag is realized. The obtained carbon-rich particles can be used as a blending combustion fuel to provide hot air for the drying process of the coal gasification slag, and the iron-rich minerals can be sold as an iron correcting agent or low-grade fine iron powder in the cement industry. The pozzolanic admixture can be used as a mixed material of Portland cement or concrete.

Description

Technical Field

[0001] The utility model belongs to the field of resource utilization of solid waste, and particularly relates to a device for classified and quality-separated utilization of coal gasification slag. Background Technique

[0002] In recent years, the rapid development and application of coal gasification technology have provided good guarantee for the efficient and clean utilization of coal in China. However, affected by the coal gasification process and coal quality, complete conversion of coal cannot be achieved during the coal gasification process. After the inorganic minerals and unburned residual carbon in coal are subjected to high-temperature oxidation in the gasifier, a large amount of coal gasification slag is generated. According to the different generation positions, the coal gasification slag can be divided into two categories: coarse slag and fine slag. Among them, the coarse slag is discharged from the bottom slag discharge port after being rapidly cooled from the molten state, generally accounting for 60% - 80% of the slag discharge amount; the fine slag is mainly generated in the dust removal device of the synthesis gas, accounting for 20% - 40% of the slag discharge amount. At present, the discharge amount of coal gasification slag in China shows an obvious increasing trend.

[0003] The bulk disposal and resource utilization of coal gasification slag have become the focus of attention of domestic and foreign scholars in recent years. At present, the resource utilization ways of coal gasification slag mainly focus on building material utilization, soil remediation, water body improvement, high-value utilization of residual carbon and siliceous minerals, etc. However, affected by coal quality, types of fluxes and gasification processes, there are great differences in the chemical composition and residual carbon content of different types of coal gasification slag, which cause great restrictions on its resource utilization. In addition, the existing methods generally perform treatment and resource utilization based on single components in the coal gasification slag, and secondary pollution may still be generated during the utilization process. Content of the Utility Model

[0004] Based on the above technical problems, the utility model proposes a device for classified and quality-separated utilization of coal gasification slag.

[0005] The technical solution adopted by the utility model is as follows:

[0006] A device for classified and quality-separated utilization of coal gasification slag includes a screening and roller grinding unit, a drying and classification unit, an iron removal unit and a grinding unit;

[0007] The screening and roller grinding unit includes a first belt scale, a classification screen and a high-pressure roller mill. The discharge end of the first belt scale is above the feed inlet of the classification screen. The discharge port of the coarse particles on the screen of the classification screen is connected to the feed inlet of the high-pressure roller mill. The discharge port of the high-pressure roller mill is above the conveyor belt; the discharge port of the fine particles under the screen of the classification screen is also above the conveyor belt;

[0008] The drying and classification unit includes a second belt scale and a drying kiln. The discharge end of the second belt scale is above the conveyor belt. The conveyor belt is connected to the feed inlet of the drying kiln. The discharge outlet of the drying kiln is connected to the feed inlet of the first air classifier. The rich carbon material outlet of the first air classifier is connected to the first cyclone separator, and the low carbon material outlet of the first air classifier is connected to a temporary storage bin. The iron removal unit includes a permanent magnet dry magnetic separator. The temporary storage bin is connected to one end of the first screw conveyor, and the other end of the first screw conveyor is connected to the feed end of a vibrating feeder. The discharge end of the vibrating feeder is connected to the feed end of the permanent magnet dry magnetic separator. The permanent magnet dry magnetic separator is provided with an iron removal material outlet and a rich iron material outlet.

[0009] The grinding unit includes a ball mill. The iron removal material outlet is connected to the inlet of the ball mill. The outlet of the ball mill is connected to the inlet of the second air classifier through a Roots blower. The outlet of the second air classifier is connected to the second cyclone separator.

[0010] Preferably, the screen hole size of the grading screen is 4 - 6 mm.

[0011] Preferably, the permanent magnet dry magnetic separator includes a first-stage magnetic roller, a second-stage magnetic roller, and a third-stage magnetic roller from top to bottom.

[0012] Preferably, the magnetic induction intensity of the first-stage magnetic roller is 3000 Gs, the magnetic induction intensity of the second-stage magnetic roller is 5000 Gs, and the magnetic induction intensity of the third-stage magnetic roller is 8000 Gs.

[0013] Preferably, the ball mill includes a first-stage ball mill, a second-stage ball mill, and a third-stage ball mill. The iron removal material outlet is connected to the inlet of the first-stage ball mill through a third belt scale. The outlet of the first-stage ball mill is connected to the inlet of the second-stage ball mill through a fourth belt scale. The outlet of the second-stage ball mill is connected to the inlet of the third-stage ball mill through a fifth belt scale. The outlet of the third-stage ball mill is connected to the Roots blower.

[0014] Preferably, a first spraying device is provided above the third belt scale, a second spraying device is provided above the fourth belt scale, and a third spraying device is provided above the fifth belt scale. The first spraying device, the second spraying device, and the third spraying device are all connected to a grinding aid storage tank through a grinding aid conveying pipeline.

[0015] Preferably, the outlet of the second air classifier is connected to the inlet of the third-stage ball mill through a material circulation pipeline.

[0016] The beneficial technical effects of the present utility model are:

[0017] (1) The present utility model proposes a device for the hierarchical and quality-separated utilization of coal gasification slag. This device is processed through procedures such as high-pressure roller grinding, drying and classification, efficient iron removal, and continuous segmented grinding to respectively obtain carbon-rich materials, iron-rich materials, and pozzolanic admixtures with a specific surface area ≥ 550 m 2 / kg and a 28-day activity index ≥ 75%, realizing the hierarchical and quality-separated utilization of coarse and fine coal gasification slag. The obtained carbon-rich particles can be used as co-firing fuel to provide hot air for the drying process of coal gasification slag. The iron-rich minerals can be sold as iron quality correctives in the cement industry or low-grade iron concentrate powder. The pozzolanic admixtures can be used as admixtures for portland cement or concrete.

[0018] (2) The high residual carbon content in gasification slag is a key problem affecting its resource utilization. The present utility model realizes the enrichment of residual carbon in fine particle materials through simple classification. On the one hand, it solves the problem of efficient separation of residual carbon in gasification slag. On the other hand, the obtained carbon-rich particles can be used as co-firing fuel to provide hot air for the drying process of coal gasification slag.

[0019] (3) The gasification slag contains inert material Fe2O3, which affects its activity as a pozzolanic admixture. The present utility model extracts iron-rich materials in gasification slag through multi-stage dry magnetic separation. This material can be sold as low-grade iron concentrate powder or iron quality correctives for cement, generating certain economic benefits.

[0020] (4) In the present utility model, the grinding aid is added in three segments. On the one hand, it can reduce the total amount of grinding aid used, saving enterprise costs. On the other hand, adding in segments can enable the finer gasification slag to continue to contact the grinding aid, preventing the gasification slag from becoming coarser.

[0021] (5) The present utility model has the advantages of simplicity, low operation and maintenance costs, etc. At the same time, it can realize the hierarchical and quality-separated utilization of coarse and fine coal gasification slag, having good economic and social benefits. Brief Description of the Drawings

[0022] Figure 1 It is a schematic structural principle diagram of the device for the hierarchical and quality-separated utilization of coal gasification slag of the present utility model.

[0023] In the figure: 1 - First belt scale; 2 - Sizing screen; 3 - High-pressure roller mill; 4 - Second belt scale; 5 - Conveyor belt; 6 - Drying kiln; 7 - First air classifier; 8 - First cyclone separator; 9 - Temporary storage bin; 10 - First screw conveyor; 11 - Vibrating feeder; 12 - Permanent magnet dry magnetic separator; 13 - Third belt scale; 14 - Grinding aid storage tank; 1401 - First spraying device; 1402 - Second spraying device; 1403 - Third spraying device; 15 - Primary ball mill; 16 - Fourth belt scale; 17 - Secondary ball mill; 18 - Fifth belt scale; 19 - Tertiary ball mill; 20 - Roots blower; 21 - Second air classifier; 22 - Second cyclone separator; 23 - Second screw conveyor; 24 - Bucket elevator; 25 - Finished product bin. Detailed implementation mode

[0024] As Figure 1 shown, a device for classified and quality-separated utilization of coal gasification slag includes a screening and roller grinding unit, a drying and classification unit, an iron removal unit, and a grinding unit. The screening and roller grinding unit includes a first belt scale 1, a sizing screen 2, and a high-pressure roller mill 3. The discharge end of the first belt scale 1 is above the feed inlet of the sizing screen 2. The discharge opening for the coarse screened materials of the sizing screen 2 is connected to the feed inlet of the high-pressure roller mill 3. The discharge outlet of the high-pressure roller mill 3 is above the conveyor belt 5. The discharge opening for the fine screened materials of the sizing screen 2 is also above the conveyor belt 5. The drying and classification unit includes a second belt scale 4 and a drying kiln 6. The discharge end of the second belt scale 4 is above the conveyor belt 5. The conveyor belt 5 is connected to the feed inlet of the drying kiln 6. The discharge outlet of the drying kiln 6 is connected to the feed inlet of the first air classifier 7. The rich carbon material outlet of the first air classifier 7 is connected to the first cyclone separator 8. The low carbon material outlet of the first air classifier 7 is connected to the temporary storage bin 9. The iron removal unit includes a permanent magnet dry magnetic separator 12, which successively includes a first-stage magnetic roller, a second-stage magnetic roller, and a third-stage magnetic roller from top to bottom. The magnetic induction intensity of the first-stage magnetic roller is 3000 Gs, the magnetic induction intensity of the second-stage magnetic roller is 5000 Gs, and the magnetic induction intensity of the third-stage magnetic roller is 8000 Gs. The temporary storage bin 9 is connected to one end of the first screw conveyor 10. The other end of the first screw conveyor 10 is connected to the feed end of the vibrating feeder 11. The discharge end of the vibrating feeder 11 is connected to the feed end of the permanent magnet dry magnetic separator 12. The permanent magnet dry magnetic separator 12 is provided with an iron removal material outlet and a rich iron material outlet. The grinding unit includes a ball mill. The iron removal material outlet is connected to the inlet of the ball mill. The outlet of the ball mill is connected to the inlet of the second air classifier 21 through a Roots blower 20. The outlet of the second air classifier 21 is connected to the second cyclone separator 22.

[0025] The utility model processes through processes such as high-pressure roller grinding, drying and classification, efficient iron removal, and continuous sectional grinding to respectively obtain carbon-rich materials, iron-rich materials, and pozzolanic admixtures with a specific surface area ≥ 550 m 2 / kg and a 28-day activity index ≥ 75%, realizing the classified and qualitative utilization of coal gasification coarse slag and fine slag. The obtained carbon-rich particles can be used as co-firing fuels to provide hot air for the drying process of coal gasification slag. The iron-rich minerals can be sold as iron quality correctives in the cement industry or low-grade iron concentrates. The pozzolanic admixtures can be used as admixtures for portland cement or concrete.

[0026] As a further design of the utility model, the ball mill includes a first-stage ball mill 15, a second-stage ball mill 17, and a third-stage ball mill 19. The iron-removed material outlet is connected to the inlet of the first-stage ball mill 15 through the third belt scale 13. The outlet of the first-stage ball mill 15 is connected to the inlet of the second-stage ball mill 17 through the fourth belt scale 16. The outlet of the second-stage ball mill 17 is connected to the inlet of the third-stage ball mill 19 through the fifth belt scale 18. The outlet of the third-stage ball mill 19 is connected to a Roots blower 20. A first spraying device 1401 is arranged above the third belt scale 13, a second spraying device 1402 is arranged above the fourth belt scale 16, and a third spraying device 1403 is arranged above the fifth belt scale 18. The first spraying device 1401, the second spraying device 1402, and the third spraying device 1403 are all connected to the grinding aid storage tank 14 through a grinding aid conveying pipeline. By adding the grinding aid in three stages, on the one hand, the total amount of grinding aid used can be reduced, saving enterprise costs. On the other hand, separate addition can enable the finer gasification slag to continue to contact the grinding aid, preventing the gasification slag from becoming coarser.

[0027] Furthermore, the outlet of the second air classifier is connected to the inlet of the third-stage ball mill 19 through a material circulation pipeline. Materials with a specific surface area not meeting the requirements can be conveyed to the third-stage ball mill 19 for re-grinding through the material circulation pipeline.

[0028] The classified and qualitative treatment process of the coal gasification slag by the utility model generally includes the following steps:

[0029] a. Screening and high-pressure roller grinding of coal gasification coarse slag;

[0030] After the coal gasification coarse slag is weighed by the first belt scale 1, it is evenly fed into the classification screen 2. The screen hole size of the classification screen is 4 - 6 mm. Through the screening of the classification screen 2, the coarse-grained materials on the screen enter the high-pressure roller mill 3 for roller pressing and crushing, and the fine-grained materials under the screen are discharged from the discharge port at the bottom of the classification screen 2 to the conveyor belt 5. The materials after roller pressing and crushing by the high-pressure roller mill 3 also fall onto the conveyor belt 5.

[0031] b. Mixing, drying, and classification of materials;

[0032] After being weighed by the second belt scale 4, the fine slag from coal gasification directly enters the conveyor belt 5. Through the transportation of the conveyor belt 5, the fine slag from coal gasification, the fine particles under the sieve in step a, and the material after being roll-pressed and crushed by the high-pressure roller mill enter the drying kiln 6 together. In the drying kiln 6, dehydration and mixing are carried out to obtain a dry mixed material. The hot air temperature in the drying kiln 6 is controlled at 300 - 400 °C, and the rotation speed of the drying kiln is 4 - 8 r / min. While dehydrating the coarse slag and fine slag from coal gasification, the drying kiln also plays a role in mixing, making the coal gasification slag mix evenly, so as to facilitate sorting in the air classifier. The mass ratio of the fine slag to the coarse slag from coal gasification is 1:3 - 1:9.

[0033] The dry mixture of coarse slag and fine slag from coal gasification discharged from the drying kiln 6 enters the first air classifier 7 for sorting. After classification, two kinds of materials, low-carbon and carbon-rich, are obtained respectively. Among them, the particles with a size of -45μm are carbon-rich materials, which enter the first cyclone separator 8 through the discharge pipe at the top of the first air classifier 7 for collection. The carbon content of the materials collected in the first cyclone separator 8 is controlled at ≥30%, and it has a certain calorific value. It can be co-fired with other fuels to generate hot air for drying the mixture of coarse slag and fine slag from coal gasification. The particles with a size of +45μm are low-carbon materials, and their main chemical components are SiO2, Al2O3, and Fe2O3, and the carbon content is controlled below 3%. The low-carbon materials enter the temporary storage bin 9 for storage and are used as pozzolanic admixtures after subsequent iron removal and grinding.

[0034] It should be noted that during the material classification process, by adjusting process parameters such as the rotation speed and air volume of the air classifier, the flexible control of the yields of low-carbon and carbon-rich materials can be achieved.

[0035] c. Iron removal of low-carbon materials;

[0036] The low-carbon materials stored in the temporary storage bin 9 are fed into the vibrating feeder 11 through the first screw conveyor 10 at the bottom to ensure that the low-carbon materials enter the permanent magnet dry magnetic separator 12 evenly for iron removal operation. The permanent magnet dry magnetic separator 12 is arranged in three levels: upper, middle, and lower. From top to bottom, it includes the first magnetic roller, the second magnetic roller, and the third magnetic roller. The magnetic induction intensity of the first magnetic roller is 3000 Gs, the magnetic induction intensity of the second magnetic roller is 5000 Gs, and the magnetic induction intensity of the third magnetic roller is 8000 Gs. The belt speed of the permanent magnet dry magnetic separator 12 is controlled at 20 - 60 r / min. After being sorted by the permanent magnet dry magnetic separator 12, the low-carbon materials are obtained as iron-removed materials and iron-rich materials. The iron-removed materials are continuously and segmentally ground later and used as pozzolanic admixtures. The iron grade of the iron-rich materials is 15 - 45%, and they can be sold as low-grade iron concentrates or cement iron quality correctives.

[0037] d. Continuous and segmented grinding of iron-removed materials;

[0038] The material after being de-ironed by the permanent magnetic dry magnetic separator 12 is fed into the third belt scale 13, and then the material is conveyed to the first-stage ball mill 15 for grinding. After being ground by the first-stage ball mill 15, the material enters the fourth belt scale 16. The material is conveyed by the fourth belt scale 16 to the second-stage ball mill 17 for grinding. After being ground by the second-stage ball mill 17, the material enters the fifth belt scale 18. The material is conveyed by the fifth belt scale 18 to the third-stage ball mill 19 for grinding.

[0039] There is a grinding aid storage tank 14 and a supporting spraying device at the belt scale. The spraying device is connected to the grinding aid storage tank 14 through a pipeline. The spraying device is arranged above the belt scale. Specifically, a first spraying device 1401 is arranged above the third belt scale 13, and the grinding aid added by the first spraying device 1401 is 0.3‰ - 0.5‰ of the mass of the material entering the mill. A second spraying device 1402 is arranged above the fourth belt scale 16, and the grinding aid added by the second spraying device 1402 is 0.2‰ - 0.3‰ of the mass of the material entering the mill. A third spraying device 1403 is arranged above the fifth belt scale 18, and the grinding aid added by the third spraying device 1403 is 0.1‰ - 0.2‰ of the mass of the material entering the mill. The spraying of the three-stage grinding aid forms a multi-stage, multi-point, and multi-level grinding aid addition method.

[0040] The material discharged from the third-stage ball mill 19 is blown to the second air classifier 21 by a Roots blower 20. After being classified by the second air classifier 21, the material with a specific surface area of more than 550 m 2 / kg is collected as the final product by the second cyclone separator 22. The material whose specific surface area does not meet the requirements is conveyed by a pipeline to the third-stage ball mill 19 for re-grinding. The final product that meets the specific surface area requirements falls into the finished product bin 25 through the second screw conveyor 23 and the bucket elevator 24. The final product obtained in the finished product bin is a pozzolanic admixture, which can be used as a mixing material for portland cement or concrete.

[0041] For the parts not described in the above method, the existing technology can be adopted or borrowed to achieve.

[0042] The above description is only a preferred embodiment of the present invention. The present invention is not limited to listing the above embodiments. It should be noted that all equivalent substitutions and obvious deformation forms made by any person skilled in the art under the teaching of this specification fall within the substantial scope of this specification and should be protected by the present invention.

Claims

1. A device for the hierarchical and quality-separated utilization of coal gasification slag, characterized in that: It includes a screening and roller grinding unit, a drying and classification unit, an iron removal unit, and a grinding unit; The screening and roller grinding unit includes a first belt scale, a sizing screen, and a high-pressure roller mill. The discharge end of the first belt scale is above the feed inlet of the sizing screen. The discharge opening of the oversize coarse material of the sizing screen is connected to the feed inlet of the high-pressure roller mill. The discharge outlet of the high-pressure roller mill is above the conveyor belt; the discharge opening of the undersize fine material of the sizing screen is also above the conveyor belt; The drying and classification unit includes a second belt scale and a drying kiln. The discharge end of the second belt scale is above the conveyor belt. The conveyor belt is connected to the feed inlet of the drying kiln. The discharge outlet of the drying kiln is connected to the feed inlet of the first pneumatic classifier. The rich carbon material outlet of the first pneumatic classifier is connected to the first cyclone separator. The low carbon material outlet of the first pneumatic classifier is connected to a temporary storage bin; The iron removal unit includes a permanent magnet dry magnetic separator. The temporary storage bin is connected to one end of the first screw conveyor. The other end of the first screw conveyor is connected to the feed end of the vibrating feeder. The discharge end of the vibrating feeder is connected to the feed end of the permanent magnet dry magnetic separator; the permanent magnet dry magnetic separator is provided with an iron removal material outlet and a rich iron material outlet; The grinding unit includes a ball mill. The iron removal material outlet is connected to the inlet of the ball mill. The outlet of the ball mill is connected to the inlet of the second pneumatic classifier through a Roots blower. The outlet of the second pneumatic classifier is connected to the second cyclone separator.

2. The classified and quality-separated utilization device for coal gasification slag according to claim 1, characterized in that: The aperture size of the sizing screen is 4 - 6 mm.

3. The classified and quality-separated utilization device for coal gasification slag according to claim 1, wherein: The permanent magnet dry magnetic separator successively includes a first-stage magnetic roller, a second-stage magnetic roller, and a third-stage magnetic roller from top to bottom.

4. The classified and quality-separated utilization device for coal gasification slag according to claim 3, characterized in that: The magnetic induction intensity of the first-stage magnetic roller is 3000 Gs, the magnetic induction intensity of the second-stage magnetic roller is 5000 Gs, and the magnetic induction intensity of the third-stage magnetic roller is 8000 Gs.

5. The apparatus for classified and quality-separated utilization of coal gasification slag according to claim 1, wherein: The ball mill includes a first-stage ball mill, a second-stage ball mill, and a third-stage ball mill; the iron removal material outlet is connected to the inlet of the first-stage ball mill through a third belt scale. The outlet of the first-stage ball mill is connected to the inlet of the second-stage ball mill through a fourth belt scale. The outlet of the second-stage ball mill is connected to the inlet of the third-stage ball mill through a fifth belt scale. The outlet of the third-stage ball mill is connected to the Roots blower.

6. The classified and quality-separated utilization device for coal gasification slag according to claim 5, wherein: A first spraying device is arranged above the third belt scale, a second spraying device is arranged above the fourth belt scale, and a third spraying device is arranged above the fifth belt scale. The first spraying device, the second spraying device, and the third spraying device are all connected to a grinding aid storage tank through a grinding aid conveying pipeline.

7. The apparatus for classified and quality-separated utilization of coal gasification slag according to claim 2, wherein: The outlet of the second pneumatic classifier is connected to the inlet of the third-stage ball mill through a material circulation pipeline.

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