Long-distance pipe coal slurry preparation gasification coal slurry system and method

Abstract

This invention discloses a long-distance pipeline coal slurry preparation system and method for gasifying coal slurry, comprising a slurry storage tank connected to the inlet of a first centrifugal pump, the outlet of the first centrifugal pump connected to the inlet of a raw coal slurry buffer tank, the raw coal slurry buffer tank connected to the inlet of a second centrifugal pump, the outlet of the second centrifugal pump connected to the inlet of a feed filter buffer tank, the feed filter buffer tank connected to a screen settling centrifuge, the centrifuged coal generated by the screen settling centrifuge falling onto a centrifugal coal scraper conveyor, the centrifugal coal scraper conveyor connected to a centrifugal coal storage yard and a centrifugal coal belt scale, the centrifugal coal belt scale connected to the inlet of a dewatered coarse coal kneader, and the dewatered coarse coal kneader connected to a low-pressure coal slurry tank. The system of this invention can simultaneously achieve efficient recovery of both coarse and fine coal slime, producing dewatered coal with low moisture content, while also concentrating and settling coal slime wastewater, reducing the load on subsequent coal slime wastewater treatment plants.

Description

Technical Field

[0001] This invention belongs to the field of coal chemical technology, specifically relating to a long-distance pipeline coal slurry preparation system for gasification coal slurry, and also to a method for preparing gasification coal slurry from long-distance pipeline coal slurry. Background Technology

[0002] Currently, long-distance pipeline coal slurry projects are relatively rare, and their applications are even more limited, mostly involving the production of dehydrated coal. However, the high moisture content of this dehydrated coal results in low particle recovery rates, increasing the load on subsequent water treatment systems. Furthermore, the application of reprocessing pipeline coal slurry into gasified coal slurry is almost nonexistent. The particle size distribution, concentration, stability, and flowability of this gasified coal slurry are key technologies and challenges in its preparation process, directly impacting gasification and combustion efficiency. Currently, most chemical plants use coal slurry produced by transporting raw coal by train or truck and then processing it through mills. However, the resulting gasified coal slurry suffers from problems such as unreasonable particle size distribution, poor flowability, and poor stability, leading to low gasification efficiency. Summary of the Invention

[0003] The purpose of this invention is to provide a long-distance pipeline coal slurry preparation system for gasification coal slurry, which solves the problems of low particle recovery rate and single product in the existing technology.

[0004] Another objective of this invention is to provide a method for preparing gasified coal slurry from long-distance pipeline coal slurry, which improves the gasification efficiency of the gasified coal slurry.

[0005] The technical solution adopted in this invention is a long-distance pipeline coal slurry preparation gasification coal slurry system, including a slurry storage tank. The slurry storage tank is connected to the inlet of a first centrifugal pump through a first pipeline. The outlet of the first centrifugal pump is connected to the inlet of a raw coal slurry buffer tank through a second pipeline. The raw coal slurry buffer tank is connected to the inlet of a second centrifugal pump through a third pipeline. The outlet of the second centrifugal pump is connected to the inlet of a feed filter buffer tank through a fourth pipeline. The feed filter buffer tank is connected to a screen settling centrifuge. The centrifugal coal generated by the screen settling centrifuge falls onto a centrifugal coal scraper conveyor. The centrifugal coal scraper conveyor is connected to a centrifugal coal storage yard and a centrifugal coal belt scale, respectively. The centrifugal coal belt scale is connected to the inlet of a dewatered coarse coal kneader. The dewatered coarse coal kneader is connected to a low-pressure coal slurry tank.

[0006] The invention is further characterized in that,

[0007] The centrifugal liquid outlet of the screen sedimentation centrifuge enters the first-stage thickener through the ninth pipe. The first-stage thickener is connected to the tenth and eleventh pipes. The tenth pipe connects to the inlet of the third centrifugal pump. The outlet of the third centrifugal pump connects to the inlet of the filter press feed tank through the twelfth pipe. The eleventh pipe connects to the second-stage thickener. The second-stage thickener connects to the fourteenth pipe. The fourteenth pipe connects to the inlet of the fourth centrifugal pump. The outlet of the fourth centrifugal pump connects to the inlet of the filter press feed tank through the sixteenth pipe. The filter press feed tank connects to the inlet of the fifth centrifugal pump through the seventeenth pipe. The discharge port of the fifth centrifugal pump is connected to the inlet of the filter press through the eighteenth pipe. The filtrate outlet of the filter press is connected to the second-stage thickener through the nineteenth pipe. The filter press is connected to the filter coal scraper conveyor. The filter coal scraper conveyor is connected to the belt conveyor. The belt conveyor is connected to the screw feed hopper. The screw feed hopper is connected to the filter coal belt scale. The filter coal belt scale is connected to the filter fine coal kneader. The filter fine coal kneader is connected to the kneading tank through the discharge port. The kneading tank is connected to the inlet of the sixth centrifugal pump through the twentieth pipe. The discharge port of the sixth centrifugal pump is connected to the inlet of the dewatered coarse coal kneader through the twenty-first pipe.

[0008] The kneading tank is connected to the inlet of the seventh centrifugal pump via pipe number twenty-two. The outlet of the seventh centrifugal pump is connected to the inlet of the coarse slurry tank via pipe number twenty-three. The coarse slurry tank is connected to the inlet of the eighth centrifugal pump via pipe number twenty-four. The outlet of the eighth centrifugal pump is connected to the inlet of the fine grinding mill via pipe number twenty-five. The fine grinding mill is connected to the fine slurry tank via pipe number twenty-six. The fine slurry tank is connected to pipe numbers twenty-seven and twenty-eight. Pipe number twenty-seven is connected to the ultrafine slurry tank. Pipe number twenty-eight is connected to the inlet of the ninth centrifugal pump. The outlet of the ninth centrifugal pump is connected to the inlet of the ultrafine grinding mill via pipe number twenty-nine. The fine grinding mill is connected to the fine slurry tank via pipe number thirtieth.

[0009] The second-stage thickener is also connected to the thirteenth pipeline, which in turn connects to the circulating clear liquid tank. The circulating clear liquid tank is then connected to the coal slime wastewater treatment station via the fifteenth pipeline. The filter press is also connected to the filter coal storage yard.

[0010] The ultrafine slurry tank is connected to the 31st and 33rd pipes respectively. The 31st pipe is connected to the inlet of the 10th centrifugal pump. The outlet of the 10th centrifugal pump is connected to the inlet of the dewatering coarse coal kneader through the 32nd pipe. The 33rd pipe is connected to the inlet of the 11th centrifugal pump. The outlet of the 11th centrifugal pump is connected to the inlet of the filter press fine coal kneader through the 34th pipe.

[0011] The outlet of the feed filter buffer tank is connected to the sixth and seventh pipes via the fifth pipe, and the sixth pipe is equipped with the first valve; the feed filter buffer tank is connected to the sixth pipe via the eighth pipe, and the sixth pipe leads into the raw coal slurry buffer tank; the seventh pipe is connected to the inlet of the screen settling centrifuge, and the seventh pipe is equipped with the second valve.

[0012] Another technical solution adopted in this invention is a method for preparing gasified coal slurry from long-distance pipeline coal slurry, which is implemented according to the following method:

[0013] Step 1: The coal slurry in the storage tank enters the first centrifugal pump through the first pipeline, and then is transported to the raw coal slurry buffer tank through the second pipeline. After being diluted with water, it enters the second centrifugal pump through the third pipeline; then it is transported to the feed filter buffer tank through the fourth pipeline.

[0014] Step 2: The coal slurry in the feed filter buffer tank enters the screen settling centrifuge, which recovers the coarse particles in the coal slurry.

[0015] Step 3: The centrifugal coal produced by the screen settling centrifuge after dewatering falls into the centrifugal coal scraper conveyor through the discharge port. Part of the centrifugal coal is transported to the centrifugal coal storage yard, and the other part falls into the centrifugal coal belt scale. The centrifugal coal belt scale is then fed into the dewatered coarse coal kneader, where water and additives are added to make slurry.

[0016] Step 4: The centrifugal liquid dewatered by the screen sedimentation centrifuge flows into the first-stage thickener through the ninth pipe for sedimentation. The underflow from the first-stage thickener enters the third centrifugal pump through the tenth pipe, and then is transported to the feed tank of the filter press through the twelfth pipe. The supernatant from the first-stage thickener overflows into the second-stage thickener through the eleventh pipe for further sedimentation, and PAM and PAC are added to accelerate sedimentation. The underflow from the second-stage thickener enters the fourth centrifugal pump through the fifteenth pipe, and then is transported to the feed tank of the filter press through the sixteenth pipe. The coal slurry in the feed tank of the filter press enters the fifth centrifugal pump through the seventeenth pipe, and then is transported to the filter press through the twelfth pipe for filter pressing and recovery of fine coal slime.

[0017] Step 5: The fine particles recovered from the filter press are unloaded onto the filter press coal scraper conveyor, and part of them fall into the belt conveyor and are transported to the screw feed hopper. Then, they are fed to the filter press fine coal kneader via the filter press coal belt scale, and water and additives are added to prepare the filter press fine slurry.

[0018] Step 6: The filtrate from the filter press is fed into the second-stage thickener through the nineteenth pipe for sedimentation, and the underflow from the second-stage thickener is finally fed back into the filter press for further recovery.

[0019] Step 7: The filter press slurry enters the kneading tank through the discharge port, and part of it enters the sixth centrifugal pump through the twentieth pipe, and then is transported to the dewatered coarse coal kneader through the twenty-first pipe to participate in the slurry preparation.

[0020] Step 8: Another portion of the coal slurry from the kneading tank enters the seventh centrifugal pump through the twenty-second pipe, and then is transported to the coarse slurry tank through the twenty-third pipe. After being diluted with water and additives, it enters the eighth centrifugal pump through the twenty-fourth pipe, and then is sent to the fine grinding mill through the twenty-fifth pipe to prepare fine slurry. The fine slurry flows into the fine slurry tank through the twenty-sixth pipe. The fine slurry at the bottom of the fine slurry tank enters the ninth centrifugal pump through the twenty-eighth pipe, and then is transported to the ultrafine grinding mill through the twenty-ninth pipe for further grinding. The slurry is returned to the fine slurry tank, and the overflow port of the fine slurry tank is connected to the ultrafine slurry tank through the twenty-seventh pipe.

[0021] Step 9: The ultrafine slurry enters the tenth centrifugal pump through the thirty-first pipeline, and is then transported to the dewatered coarse coal kneader through the thirty-second pipeline to prepare gasification slurry; at the same time, it enters the eleventh centrifugal pump through the thirty-third pipeline, and is then transported to the filter press fine coal kneader through the thirty-fourth pipeline to prepare filter press fine slurry.

[0022] Step 10 involves adding water, additives, centrifugal coal conveyed by a centrifugal coal belt scale, ultrafine slurry conveyed from pipeline 32, and filter press slurry conveyed from pipeline 21 to a dewatered coarse coal kneader to prepare gasification coal slurry. The slurry is then fed into a low-pressure coal slurry tank via a discharge chute and subsequently transported to a chemical plant for gasification.

[0023] The beneficial effects of this invention are: the system can simultaneously achieve efficient recovery of both coarse and fine coal slime, producing dewatered coal with low moisture content, while also concentrating and settling coal slime wastewater, reducing the load on subsequent coal slime wastewater treatment plants. Depending on production volume and user needs, the system can simultaneously produce multiple products such as centrifugal coal, filter press coal, and gasified coal slurry, and these products are convenient for graded storage and management. The third-generation three-peak particle size distribution enrichment process and the medium-concentration dewatering + ultrafine grinding slurry preparation process result in a more reasonable particle size distribution of the gasified slurry. The addition of a small amount of additives in the process greatly optimizes the stability and fluidity of the gasified slurry, significantly improving the gasification efficiency of the coal slurry. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of a long-distance pipeline coal slurry preparation gasification coal slurry system according to the present invention;

[0025] Figure 2 This is a flowchart of a method for preparing gasified coal slurry from long-distance pipeline coal slurry in an embodiment of the present invention.

[0026] In the diagram, 1. Slurry storage tank, 2. Raw coal slurry buffer tank, 3. Feed filter buffer tank, 4. Screen settling centrifuge, 5. Centrifugal coal scraper conveyor, 6. Centrifugal coal belt scale, 7. Dewatered coarse coal kneader, 8. Primary thickener, 9. Secondary thickener, 10. Circulating clear liquid tank, 11. Coal slime wastewater treatment station, 12. Filter press feed tank, 13. Filter press, 14. Filter press scraper conveyor, 15. Belt conveyor, 16. Screw feed hopper, 17. Filter press coal belt scale, 18. Filter press fine coal kneader. 19. Mixer, 20. Kneading tank, 21. Coarse slurry tank, 22. Fine grinding mill, 23. Fine slurry tank, 24. Ultrafine grinding mill, 25. Ultrafine slurry tank, 26. Centrifugal coal storage yard, 27. Filter press coal storage yard, 28. Low-pressure coal slurry tank, 29. First centrifugal pump, 20. Second centrifugal pump, 31. First valve, 32. Second valve, 33. Third centrifugal pump, 34. Fourth centrifugal pump, 35. Fifth centrifugal pump, 36. Sixth centrifugal pump, 37. Seventh centrifugal pump, 38. Eighth centrifugal pump. 39. Ninth centrifugal pump, 40. Tenth centrifugal pump, 41. Eleventh centrifugal pump, 42. First pipeline, 43. Second pipeline, 44. Third pipeline, 45. Fourth pipeline, 46. Fifth pipeline, 47. Sixth pipeline, 48. Seventh pipeline, 49. Eighth pipeline, 50. Ninth pipeline, 51. Tenth pipeline, 52. Eleventh pipeline, 53. Twelfth pipeline, 54. Thirteenth pipeline, 55. Fourteenth pipeline, 56. Fifteenth pipeline, 57. Sixteenth pipeline, 58. Seventeenth pipeline 58. Pipeline 18, 59. Pipeline 19, 60. Pipeline 20, 61. Pipeline 21, 62. Pipeline 22, 63. Pipeline 23, 64. Pipeline 24, 65. Pipeline 25, 66. Pipeline 26, 67. Pipeline 27, 68. Pipeline 28, 69. Pipeline 29, 70. Pipeline 30, 71. Pipeline 31, 72. Pipeline 32, 73. Pipeline 33, 74. Pipeline 34. Detailed Implementation

[0027] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0028] This invention discloses a long-distance pipeline coal slurry preparation system for gasification coal slurry, such as... Figure 1As shown, the system includes a slurry storage tank 1, which is connected to the inlet of a first centrifugal pump 28 via a first pipe 41. The outlet of the first centrifugal pump 28 is connected to the inlet of a raw coal slurry buffer tank 2 via a second pipe 42. A water addition point is provided at the raw coal slurry buffer tank 2. The raw coal slurry buffer tank 2 is connected to the inlet of a second centrifugal pump 29 via a third pipe 43. The outlet of the second centrifugal pump 29 is connected to the inlet of a feed filter buffer tank 3 via a fourth pipe 44. The outlet of the feed filter buffer tank 3 can enter a sixth pipe 46 and a seventh pipe 47 via a fifth pipe 45. A first valve 30 is provided on the sixth pipe 46. The feed filter buffer tank 3 is connected to the sixth pipe 46 via an eighth pipe 48. The sixth pipe 46 leads into the raw coal slurry buffer tank 2.

[0029] The seventh pipe 47 is connected to the inlet of the screen sedimentation centrifuge 4. The seventh pipe 47 is equipped with a second valve 31. The centrifugal liquid outlet of the screen sedimentation centrifuge 4 enters the first-stage thickener 8 through the ninth pipe 49. The centrifugal coal produced by the screen sedimentation centrifuge 4 falls through the centrifuge discharge port to the centrifugal coal scraper conveyor 5. The centrifugal coal scraper conveyor 5 can respectively transport coal slime to the centrifugal coal storage yard 25 and the centrifugal coal belt scale 6. The centrifugal coal belt scale 6 is connected to the inlet of the dewatered coarse coal kneader 7. The dewatered coarse coal kneader 7 is equipped with water and additive points.

[0030] The first-stage thickener 8 is connected to the tenth pipe 50 and the eleventh pipe 51. The tenth pipe 50 is connected to the inlet of the third centrifugal pump 32. The outlet of the third centrifugal pump 32 is connected to the inlet of the filter press feed tank 12 via the twelfth pipe 52. The eleventh pipe 51 is connected to the second-stage thickener 9. The second-stage thickener 9 is equipped with PAM and PAC dosing points. The second-stage thickener 9 is connected to the thirteenth pipe 53 and the fourteenth pipe 54. The thirteenth pipe 53 is connected to the circulating clear liquid tank 10, and then to the coal slime wastewater treatment station 11 via the fifteenth pipe 55. The fourteenth pipe 54 is connected to the inlet of the fourth centrifugal pump 33. The outlet of the fourth centrifugal pump 33 is connected to the inlet of the filter press feed tank 12 via the sixteenth pipe 56. The filter press feed tank 12 is connected to the inlet of the fifth centrifugal pump 34 via the seventeenth pipe 57. The discharge port of centrifugal pump 34 is connected to the inlet of filter press 13 through the eighteenth pipe 58. The filtrate outlet of filter press 13 is connected to the second-stage thickener 9 through the nineteenth pipe 59. The filter coal produced by filter press 13 can be transported to filter coal storage yard 26 and filter coal scraper conveyor 14 respectively, and then to belt conveyor 15 through gate. The belt conveyor 15 transports the coal to screw receiving bin 16. Screw receiving bin 16 is connected to filter coal belt scale 17. Filter coal belt scale 17 is connected to filter fine coal kneader 18. Filter fine coal kneader 18 is equipped with water and additive points. Filter fine coal kneader 18 is connected to kneading tank 19 through discharge port. Kneading tank 19 is connected to the inlet of sixth centrifugal pump 35 through the twentieth pipe 60. The discharge port of sixth centrifugal pump 35 is connected to the inlet of dewatered coarse coal kneader 7 through the twenty-first pipe 61.

[0031] The kneading tank 19 is connected to the inlet of the seventh centrifugal pump 36 via the twenty-second pipe 62. The outlet of the seventh centrifugal pump 36 is connected to the inlet of the coarse slurry tank 20 via the twenty-third pipe 63. The coarse slurry tank 20 is equipped with a water addition and additive point. The coarse slurry tank 20 is connected to the inlet of the eighth centrifugal pump 37 via the twenty-fourth pipe 64. The outlet of the eighth centrifugal pump 37 is connected to the inlet of the fine grinding mill 21 via the twenty-fifth pipe 65. The fine grinding mill 21 is connected to the fine slurry tank 22 via the twenty-sixth pipe 66. The fine slurry tank 22 is connected to the twenty-seventh pipe 67 and the twenty-eighth pipe 68. The twenty-seventh pipe 67 is connected to the ultrafine slurry tank 24. The twenty-eighth pipe 68 is connected to the inlet of the ninth centrifugal pump 38. The outlet of the ninth centrifugal pump 38 is connected to the inlet of the ultrafine grinding mill 23 via the twenty-ninth pipe 69. The ultrafine grinding mill 23 is equipped with an additive point and is connected to the fine slurry tank 22 via the thirtieth pipe 70.

[0032] The ultrafine slurry tank 24 is connected to the thirty-first pipe 71 and the thirty-third pipe 73 respectively. The thirty-first pipe 71 is connected to the inlet of the tenth centrifugal pump 39. The outlet of the tenth centrifugal pump 39 is connected to the inlet of the dewatering coarse coal kneader 7 through the thirty-second pipe 72. The dewatering coarse coal kneader 7 is connected to the low-pressure coal slurry tank 27 through the discharge port. The thirty-third pipe 73 is connected to the inlet of the eleventh centrifugal pump 40. The outlet of the eleventh centrifugal pump 40 is connected to the inlet of the filter press fine coal kneader 18 through the thirty-fourth pipe 74.

[0033] This invention discloses a method for preparing gasified coal slurry from long-distance pipeline coal slurry. The method utilizes the aforementioned pipeline coal slurry to prepare gasified coal slurry, and is specifically implemented according to the following steps:

[0034] Step 1: The pipeline coal slurry is stored in the slurry storage tank 1. The pipeline coal slurry in the slurry storage tank 1 enters the first centrifugal pump 28 through the first pipeline 41, and then is transported to the raw coal slurry buffer tank 2 through the second pipeline 42. After being diluted with water, it enters the second centrifugal pump 29 through the third pipeline 43; then it is transported to the centrifuge feed filter buffer tank 3 through the fourth pipeline 44.

[0035] The mass concentration of pipeline coal slurry is 51-55%, and the mass concentration of coal slurry in the raw coal slurry buffer tank after dilution with water is 40-55%; the specific need for dilution with water can be considered based on the actual production situation.

[0036] Step 2: Close the first valve 30 and open the second valve 31. The coal slurry in the feed filter buffer tank 3 enters the screen settling centrifuge 4, and the screen settling centrifuge 4 recovers the coarse particles in the coal slurry.

[0037] When the feed filter buffer tank 3 overflows, it can be returned to the raw coal slurry buffer tank 2 through the eighth pipe 48, forming an internal circulation between the feed filter buffer tank 3 and the raw coal slurry buffer tank 2; when the centrifuge fails and stops, the coal slurry remains in the feed filter buffer tank 3 and accumulates and blocks the pipeline. Open the first valve 30 and close the second valve 31, and the coal slurry is introduced into the raw coal slurry buffer tank 2 to prevent the coal slurry from settling and blocking the feed port and slag outlet in the feed filter buffer tank 3.

[0038] Step 3: The centrifugal coal produced by the screen settling centrifuge 4 after dewatering falls into the centrifugal coal scraper conveyor 5 through the discharge port. Depending on the production capacity and user usage, a portion of the centrifugal coal can be transported to the centrifugal coal storage yard 25, while the other portion becomes the centrifugal coal for gasification slurry preparation and falls into the centrifugal coal belt scale 6. The centrifugal coal belt scale 6 is then fed into the dewatered coarse coal kneader 7, where water and additives are added to prepare the slurry.

[0039] The dewatered centrifuged coal product from screen sedimentation centrifuge 4 has a moisture content of ≤23%; the mass concentration of the additive is 0-20%.

[0040] Step 4: The centrifugal liquid dewatered by the screen sedimentation centrifuge 4 flows into the first-stage thickener 8 through the ninth pipe 49 for sedimentation. The underflow from the first-stage thickener 8 enters the third centrifugal pump 32 through the tenth pipe 50, and then is transported to the filter press feed tank 12 through the twelfth pipe 52. The supernatant from the first-stage thickener 8 overflows into the second-stage thickener 9 through the eleventh pipe 51 for further sedimentation, and PAM and PAC are added to accelerate sedimentation. The underflow from the second-stage thickener 9 enters the fourth centrifugal pump 33 through the fifteenth pipe 55, and then is transported to the filter press feed tank 12 through the sixteenth pipe 56. The coal slurry in the filter press feed tank 12 enters the fifth centrifugal pump 34 through the seventeenth pipe 57, and then is transported to the filter press 13 through the twelfth pipe 52 for filter pressing and recovery of fine coal slime.

[0041] The mass concentration of the centrifuged liquid after dehydration by screen sedimentation centrifuge 4 is ≤40%.

[0042] The moisture content of the fine coal slime recovered by filter press 13 is ≤33%;

[0043] Step 5: The fine particles recovered from the filter press are unloaded onto the filter press coal scraper conveyor 14. Part of the filter press coal is transported to the filter press coal storage yard 26, and the other part falls into the belt conveyor 15 and is transported to the screw receiving hopper 16. Then, the filter press coal is fed to the filter press fine coal kneader 18 through the filter press coal belt scale 17. Water and additives are added to prepare the filter press fine slurry.

[0044] In the preparation of filter press fine slurry using the filter press fine coal kneader 18, the mass ratio of filter press fine coal, fine slurry / ultrafine slurry, and additives is 25:2.5:0.13, with the additives added at 0.3% of the total dry coal content; the mass concentration of the filter press fine slurry is 40%-58%.

[0045] Formula for preparing filter press slurry:

[0046] 1. Filtration coal consumption (Q) 压 )

[0047]

[0048] Where: V6—target slurry volume (finished coal slurry), m 3 / h; C—Target concentration of finished coal slurry, %; ρ6—Density of finished coal slurry, t / m³ 3 p5—Dry coal content of filter press fine coal, %; M2—Moisture content of filter press fine coal, %.

[0049] 2. Fine / Ultrafine Slurry Dosage (Q) 超 )

[0050]

[0051] Where: V6—target slurry volume (finished coal slurry), m 3 / h; C—Target concentration of finished coal slurry, %; ρ6—Density of finished coal slurry, t / m³ 3 p6—Dry coal percentage in fine / ultrafine slurry, %; ρ1—Density of fine / ultrafine slurry, t / m³ 3 C3—Fine / Ultrafine pulp concentration, %.

[0052] 3. Additive dosage (Q) 添 )

[0053]

[0054] Where: V6—target slurry volume (finished coal slurry), m 3 / h; C—Target concentration of finished coal slurry, %; ρ6—Density of finished coal slurry, t / m³ 3 p7—Additive dry basis percentage, %; ρ3—Additive density, t / m³ 3 C5 — Additive concentration, %.

[0055] 4. Water consumption (Q) 水 )

[0056]

[0057] Where: V6—target slurry volume (finished coal slurry), m 3 / h; C—Target concentration of finished coal slurry, %; ρ6—Density of finished coal slurry, t / m³ 3 C4—Concentration of coal slurry in the kneading tank, %; ρ1—Density of fine / ultrafine slurry, t / m³ 3 ρ3—Additive density, t / m³ 3 ρ5—Slurry density from the kneading tank, t / m³ 3 p6—Dry coal percentage of fine / ultrafine slurry, %; p7—Additive dry basis percentage, %.

[0058] Step 6: The filtrate from the filter press 13 is fed into the second-stage thickener 9 through the nineteenth pipe 59 for sedimentation. The underflow from the second-stage thickener 9 eventually flows back into the filter press 13 for further recovery. The supernatant from the second-stage thickener 9 flows into the circulating clear liquid tank 10 through the thirteenth pipe 53. The water in the circulating clear liquid tank 10 is used for water addition points, additive preparation water, and equipment flushing water in the process flow. The remainder is transported to the coal slime water treatment station 11 for water treatment.

[0059] Step 7: The filter press slurry enters the kneading tank 19 through the discharge port. A portion of it enters the sixth centrifugal pump 35 through the twentieth pipe 60, and then is transported to the dewatered coarse coal kneader 7 through the twenty-first pipe 61 to participate in the slurry preparation.

[0060] Step 8: Another portion of the coal slurry from the kneading tank 19 enters the seventh centrifugal pump 36 through the twenty-second pipe 62, and then is transported to the coarse slurry tank 20 through the twenty-third pipe 63. After dilution with water and additives, it enters the eighth centrifugal pump 37 through the twenty-fourth pipe 64, and then is sent to the fine grinding mill 21 through the twenty-fifth pipe 65 to prepare fine slurry. The fine slurry flows into the fine slurry tank 22 through the twenty-sixth pipe 66. The fine slurry at the bottom of the fine slurry tank 22 enters the ninth centrifugal pump 38 through the twenty-eighth pipe 68, and then is transported to the ultrafine grinding mill 23 through the twenty-ninth pipe 69 for further grinding. The slurry is returned to the fine slurry tank 22. The overflow port of the fine slurry tank 22 can be connected to the ultrafine slurry tank 24 through the twenty-seventh pipe 67.

[0061] The average particle size of the output from the fine grinding mill 21 is approximately 20-30 μm, while the average particle size of the output from the ultrafine grinding mill 23 is approximately 5 μm. The amount of additive added to the ultrafine grinding mill 23 can be adjusted according to the stability and fluidity of the coal slurry in actual production.

[0062] The ultrafine slurry ground by the ultrafine mill 23 flows back to the fine slurry tank 22 through the thirtieth pipe 70, forming an internal circulation between the ultrafine mill and the fine slurry tank; the overflow port of the fine slurry tank 22 is connected to the ultrafine slurry tank 24 through the twenty-seventh pipe 67, and the ultrafine mill, fine slurry tank and ultrafine slurry tank form a balanced state for preparing fine slurry / ultrafine slurry;

[0063] Step 9: The ultrafine slurry tank 24 can enter the tenth centrifugal pump 39 through the thirty-first pipe 71, and then be transported to the dewatered coarse coal kneader 7 through the thirty-second pipe 72 to prepare gasification slurry; at the same time, it enters the eleventh centrifugal pump 40 through the thirty-third pipe 73, and then be transported to the filter press fine coal kneader 18 through the thirty-fourth pipe 74 to prepare filter press fine slurry.

[0064] The coal slurry concentration in the ultrafine slurry tank 24 is 30-46%;

[0065] Step 10 involves adding water, additives, centrifugal coal conveyed by centrifugal coal belt scale 6, ultrafine slurry conveyed by pipeline 32, and filter slurry conveyed by pipeline 21 to the dewatered coarse coal kneader 7 to prepare gasification coal slurry. The slurry is then fed into the low-pressure coal slurry tank 27 via a discharge chute and then transported to the chemical plant for gasification.

[0066] The mass ratio of centrifuged coal, filter press slurry, additives, and ultrafine slurry used in the preparation of gasified coal slurry is 75:15:10:0.17; the mass concentration of the gasified coal slurry is 63-69%.

[0067] 1. Formula for calculating the proportion of gasified coal slurry

[0068] (1) Centrifugal coal consumption (Q) 离 )

[0069]

[0070] Where: V6—target slurry production (finished coal slurry), m 3 / h; M1—Measured moisture content of centrifuged coal, %; C—Target concentration of finished coal slurry, %; ρ6—Density of finished coal slurry, t / m³ 3 p1—Percentage of dry coal produced by centrifugal coal, %.

[0071] (2) Filter press pulp dosage (Q) 压 )

[0072]

[0073] Where: V6—target slurry volume (finished coal slurry), m 3 / h; C4—Concentration of coal slurry in the kneading tank, %; C—Target concentration of finished coal slurry, %; ρ6—Density of finished coal slurry, t / m³ 3 p2—Proportion of dry fine coal in filter press, %; ρ5—Density of slurry from kneading tank, t / m³ 3 ;

[0074] (3) Ultrafine pulp dosage (Q) 超 )

[0075]

[0076] Where: V6—target slurry volume (finished coal slurry), m 3 / h; C—Target concentration of finished coal slurry, %; ρ6—Density of finished coal slurry, t / m³ 3 p3—Dry coal content in ultrafine slurry, %, (designed to be 10%); ρ1—Density of fine slurry / ultrafine slurry, t / m³ 3 C3—Fine / Ultrafine pulp concentration, %.

[0077] (4) Amount of additives (Q) 添 )

[0078]

[0079] Where: V6—target slurry volume (finished coal slurry), m 3 / h; C—Target concentration of finished coal slurry, %; ρ6—Density of finished coal slurry, t / m³ 3 p4—Additive dry basis percentage, %; ρ3—Additive density, t / m³ 3 C5 — Additive concentration, %.

[0080] (5) Process water consumption (Q) 水 )

[0081] Q 水 =V6*ρ6-Q 离 -Q 压 *ρ5-Q超 *ρ1-Q 添 *ρ3

[0082] Where: V6—target slurry volume (finished coal slurry), m 3 / h; ρ6—density of finished coal slurry, t / m³ 3 ρ5—Slurry density from the kneading tank, t / m³ 3 ρ1—Density of fine / ultrafine pulp, t / m³ 3 ρ3—Additive density, t / m³ 3 .

[0083] 2. Finished coal slurry concentration (C)

[0084]

[0085] Where: m1—mass of dewatered coarse coal per unit time, t / h; M1—moisture content of centrifuged coal, %; V1—volume of fine / ultrafine slurry per unit time, m³ 3 / h; ρ1—density of fine / ultrafine pulp, t / m³ 3 C3—Fine / Ultrafine pulp concentration, %; V2—Pulp volume received from the kneading tank per unit time, m³ 3 / h; ρ2—Slurry density from the kneading tank, t / m³ 3 C4—Concentration of coal slurry in the kneading tank, %; V3—Volume of additive per unit time, m³ 3 / h; ρ3—additive density, t / m 3 C5—Additive concentration, %; V4—Process water volume per unit time, m³ 3 / h; ρ4—density of water, t / m³ 3 .

[0086] Example

[0087] In this embodiment, the pipeline coal slurry is a 51-53% coal slurry obtained from raw coal from Hongliulin. The process flow for preparing the gasification slurry is as follows: Figure 2 As shown, the specific steps include:

[0088] Step 1: 51-53% of the pipeline coal slurry stored in the slurry storage tank is transported to the raw coal slurry buffer tank and then to the screen settling centrifuge for centrifugal dewatering. The dewatered coarse coal with a moisture content of about 16-23% enters the dewatered coarse coal kneader and is mixed with water, 7%-17% concentration of additives, filter press fine slurry, and fine / ultrafine slurry.

[0089] Step 2: The centrifuged liquid with a concentration of ≤28% from the screen sedimentation centrifuge enters the first-stage thickener for primary sedimentation. The supernatant from the first-stage thickener overflows to the second-stage thickener for secondary sedimentation, and PAC and PAM are added to accelerate sedimentation. The underflow from the first and second-stage thickeners enters the feed buffer tank of the filter press and is then transported to the filter press to recover fine coal slurry from the coal slurry water. The filter press recovers fine coal with a moisture content of 23-32% and enters the filter press fine coal kneader. It is mixed with water, additives, and fine / ultrafine slurry to prepare a 40-47% filter press fine slurry. The ratio of filter press fine coal to fine / ultrafine slurry is 0.90-3.50, and the additive ratio is 0.0009%-0.007%. The filtrate is then collected again by sedimentation in the second-stage thickener. A portion of the filter press fine slurry is directly fed into the dewatering coarse coal kneader for slurry preparation.

[0090] Step 3: Another portion of the filter press slurry enters the coarse slurry tank, is diluted to 30%-45%, and then is sent to a fine grinding mill and an ultrafine grinding mill for grinding to prepare a fine / ultrafine slurry with a concentration of 36%-45%.

[0091] Step 4: Prepare gasification coal slurry by centrifuging coarse coal, filter press fine slurry, fine slurry / ultrafine slurry, water, and additives. The additives account for 0-0.003% of the dry coal. The ratio of centrifuged coarse coal: filter press fine coal: fine slurry / ultrafine slurry is 65:25:10, and the concentration of gasification coal slurry is about 64-68%.

[0092] The production values ​​of centrifuged coal, filter press coal, and gasification slurry during production are shown in Table 1-3:

[0093] Table 1 Production Value of Centrifuged Coal with Moisture Content

[0094]

[0095] Table 2 Production Value of Filter Coal with Moisture Content

[0096]

[0097] Table 3 Production Value of Gasification Pulp Concentration

[0098]

[0099] This invention relates to a long-distance pipeline coal slurry preparation system for gasification slurry. Through the rational coordination of a slurry storage tank, a raw coal slurry buffer tank, a screen settling centrifuge, a primary thickener, a secondary thickener, a filter press, a dosing machine, a coal storage yard, a coal slime wastewater treatment station, a dewatered coarse coal kneader, a filter press fine coal kneader, a fine mill, an ultrafine mill, and multiple valves, the system allows for timely adjustments to the production process when the coal slurry properties change. The system employs a third-generation three-peak particle size distribution thickening process and a medium-concentration dewatering + ultrafine grinding slurry preparation process, resulting in a gasification slurry with good particle size distribution, stability, and fluidity, thus improving the gasification efficiency. This ensures both product quality and output, enabling stable production. Simultaneously, the two-stage thickening process effectively concentrates and settles the coal slime water, significantly reducing the treatment load on subsequent coal slime wastewater and ensuring that the wastewater treatment meets standards.

[0100] The long-distance pipeline coal slurry preparation gasification slurry system of the present invention has good dewatering effect, low moisture content of dewatered products, and a variety of products. It maximizes the recovery of coal slime, simplifies the user's gasification slurry preparation process, and produces high-quality gasification slurry, thereby improving the coal slime recovery rate in pipeline coal slurry and the gasification efficiency of gasification slurry.

Claims

1. A long-distance pipeline coal slurry preparation system for gasification coal slurry, characterized in that, The system includes a slurry storage tank (1), which is connected to the inlet of a first centrifugal pump (28) via a first pipe (41). The outlet of the first centrifugal pump (28) is connected to the inlet of a raw coal slurry buffer tank (2) via a second pipe (42). The raw coal slurry buffer tank (2) is connected to the inlet of a second centrifugal pump (29) via a third pipe (43). The outlet of the second centrifugal pump (29) is connected to a feed filter buffer tank via a fourth pipe (44). 3) The feed filter buffer tank (3) is connected to the screen settling centrifuge (4). The centrifugal coal generated by the screen settling centrifuge (4) falls onto the centrifugal coal scraper conveyor (5). The centrifugal coal scraper conveyor (5) is connected to the centrifugal coal storage yard (25) and the centrifugal coal belt scale (6) respectively. The centrifugal coal belt scale (6) is connected to the feed port of the dewatered coarse coal kneader (7). The dewatered coarse coal kneader (7) is connected to the low-pressure coal slurry tank (27). The centrifugal liquid outlet of the screen sedimentation centrifuge (4) enters the first-stage thickener (8) through the ninth pipe (49). The first-stage thickener (8) is connected to the tenth pipe (50) and the eleventh pipe (51). The tenth pipe (50) is connected to the inlet of the third centrifugal pump (32). The outlet of the third centrifugal pump (32) is connected to the inlet of the filter press feed tank (12) through the twelfth pipe (52). The eleventh pipe (51) is connected to the second-stage thickener (9). The second-stage thickener (9) is connected to the fourteenth pipe (54). The fourteenth pipe (54) is connected to the inlet of the fourth centrifugal pump (33). The outlet of the fourth centrifugal pump (33) is connected to the inlet of the filter press feed tank (12) through the sixteenth pipe (56). The filter press feed tank (12) is connected to the inlet of the fifth centrifugal pump (34) through the seventeenth pipe (57). The outlet of the five centrifugal pump (34) is connected to the inlet of the filter press (13) through the eighteenth pipe (58). The filtrate outlet of the filter press (13) is connected to the second stage thickener (9) through the nineteenth pipe (59). The filter press (13) is connected to the filter coal scraper conveyor (14). The filter coal scraper conveyor (14) is connected to the belt conveyor (15). The belt conveyor (15) is connected to the spiral receiving bin (16). The spiral receiving bin (16) is connected to the filter coal belt scale (17). The filter coal belt scale (17) is connected to the filter fine coal kneader (18). The filter fine coal kneader (18) is connected to the kneading tank (19) through the discharge port. The kneading tank (19) is connected to the inlet of the sixth centrifugal pump (35) through the twentieth pipe (60). The outlet of the sixth centrifugal pump (35) is connected to the inlet of the dewatered coarse coal kneader (7) through the twenty-first pipe (61). The outlet of the feed filter buffer tank (3) is connected to the sixth pipe (46) and the seventh pipe (47) respectively through the fifth pipe (45). The sixth pipe (46) is equipped with a first valve (30). The feed filter buffer tank (3) is connected to the sixth pipe (46) through the eighth pipe (48). The sixth pipe (46) leads into the raw coal slurry buffer tank (2). The seventh pipe (47) is connected to the inlet of the screen settling centrifuge (4). The seventh pipe (47) is equipped with a second valve (31). The kneading tank (19) is connected to the inlet of the seventh centrifugal pump (36) via the twenty-second pipe (62). The outlet of the seventh centrifugal pump (36) is connected to the inlet of the coarse slurry tank (20) via the twenty-third pipe (63). The coarse slurry tank (20) is connected to the inlet of the eighth centrifugal pump (37) via the twenty-fourth pipe (64). The outlet of the eighth centrifugal pump (37) is connected to the inlet of the fine grinding mill (21) via the twenty-fifth pipe (65). The fine grinding mill (21) is connected to the inlet of the fine grinding mill (21) via the twenty-sixth pipe. (66) Connect the fine slurry tank (22), which is connected to the twenty-seventh pipe (67) and the twenty-eighth pipe (68) respectively. The twenty-seventh pipe (67) is connected to the ultrafine slurry tank (24), and the twenty-eighth pipe (68) is connected to the feed port of the ninth centrifugal pump (38). The discharge port of the ninth centrifugal pump (38) is connected to the inlet of the ultrafine mill (23) through the twenty-ninth pipe (69). The ultrafine mill (23) is connected to the fine slurry tank (22) through the thirtieth pipe (70).

2. The long-distance pipeline coal slurry preparation gasification coal slurry system according to claim 1, characterized in that, The second-stage thickener (9) is also connected to the thirteenth pipe (53), which is connected to the circulating clear liquid tank (10), and the circulating clear liquid tank (10) is connected to the coal slime wastewater treatment station (11) through the fifteenth pipe (55); the filter press (13) is also connected to the filter coal storage yard (26).

3. The long-distance pipeline coal slurry preparation gasification coal slurry system according to claim 1, characterized in that, The ultrafine slurry tank (24) is connected to the thirty-first pipe (71) and the thirty-third pipe (73) respectively. The thirty-first pipe (71) is connected to the inlet of the tenth centrifugal pump (39). The outlet of the tenth centrifugal pump (39) is connected to the inlet of the dewatering coarse coal kneader (7) through the thirty-second pipe (72). The thirty-third pipe (73) is connected to the inlet of the eleventh centrifugal pump (40). The outlet of the eleventh centrifugal pump (40) is connected to the inlet of the filter press fine coal kneader (18) through the thirty-fourth pipe (74).

4. A method for preparing gasified coal slurry from long-distance pipeline coal slurry, characterized in that, The long-distance pipeline coal slurry preparation gasification coal slurry system as described in claim 3 is implemented according to the following method: Step 1: The coal slurry in the storage tank (1) enters the first centrifugal pump (28) through the first pipeline (41), and then is transported to the raw coal slurry buffer tank (2) through the second pipeline (42). After being diluted with water, it enters the second centrifugal pump (29) through the third pipeline (43); then it is transported to the feed filter buffer tank (3) through the fourth pipeline (44). Step 2: The coal slurry in the feed filter buffer tank (3) enters the screen settling centrifuge (4), and the screen settling centrifuge (4) recovers the coarse particles in the coal slurry; When the feed filter buffer tank (3) overflows, it flows back to the raw coal slurry buffer tank (2) through the eighth pipe (48), forming an internal circulation between the feed filter buffer tank (3) and the raw coal slurry buffer tank (2); when the centrifuge stops due to failure, the coal slurry remains in the feed filter buffer tank (3) and accumulates and blocks the pipeline. Open the first valve (30) and close the second valve (31) to allow the coal slurry to flow into the raw coal slurry buffer tank (2) to prevent the coal slurry from settling and blocking the feed port and slag outlet in the feed filter buffer tank (3); Step 3: The centrifugal coal produced by the screen settling centrifuge (4) after dewatering falls into the centrifugal coal scraper conveyor (5) through the discharge port. Part of the centrifugal coal is transported to the centrifugal coal storage yard (25), and the other part of the centrifugal coal falls into the centrifugal coal belt scale (6). The centrifugal coal belt scale (6) is then fed into the dewatered coarse coal kneader (7), and water and additives are added to make slurry. Step 4: The centrifugal liquid dehydrated by the screen sedimentation centrifuge (4) flows into the first-stage thickener (8) through the ninth pipe (49) for sedimentation. The underflow of the first-stage thickener (8) enters the third centrifugal pump (32) through the tenth pipe (50) and is then transported to the filter press feed tank (12) through the twelfth pipe (52). The supernatant of the first-stage thickener (8) overflows into the second-stage thickener (9) through the eleventh pipe (51) for further sedimentation. PAM and PAC are added to accelerate sedimentation. The underflow of the second-stage thickener (9) enters the fourth centrifugal pump (33) through the fifteenth pipe (55) and is then transported to the filter press feed tank (12) through the sixteenth pipe (56). The coal slurry in the filter press feed tank (12) enters the fifth centrifugal pump (34) through the seventeenth pipe (57) and is then transported to the filter press (13) through the twelfth pipe (52) for filter pressing and recovery of fine coal slurry. Step 5: The fine particles recovered from the filter press are unloaded onto the filter press coal scraper conveyor (14), and part of them fall into the belt conveyor (15) and are transported to the screw receiving bin (16). Then, they are fed to the filter press fine coal kneader (18) through the filter press coal belt scale (17), and water and additives are added to prepare the filter press fine slurry. In the preparation of filter press fine slurry using a fine coal kneader (18), the mass ratio of filter press fine coal, fine slurry / ultrafine slurry, and additives is 25:2.5:0.13, with the additives added at 0.3% of the total dry coal content; the mass concentration of the filter press fine slurry is 40%-58%. Step 6: The filtrate from the filter press (13) is fed into the second stage thickener (9) through the nineteenth pipe (59) for sedimentation. The underflow from the second stage thickener (9) is then fed into the filter press (13) for further recovery. Step 7: The filter press slurry enters the kneading tank (19) through the discharge port, and part of it enters the sixth centrifugal pump (35) through the twentieth pipe (60), and then is transported to the dewatered coarse coal kneader (7) through the twenty-first pipe (61) to participate in the slurry preparation; Step 8: Another portion of the coal slurry from the kneading tank (19) enters the seventh centrifugal pump (36) through the twenty-second pipe (62), and is then transported to the coarse slurry tank (20) through the twenty-third pipe (63) for dilution with water and additives. After dilution, it enters the eighth centrifugal pump (37) through the twenty-fourth pipe (64), and is then sent to the fine grinding mill (21) through the twenty-fifth pipe (65) to prepare fine slurry. The fine slurry flows into the fine slurry tank (22) through the twenty-sixth pipe (66). The fine slurry at the bottom of the fine slurry tank (22) enters the ninth centrifugal pump (38) through the twenty-eighth pipe (68), and is then transported to the ultrafine grinding mill (23) through the twenty-ninth pipe (69) for further grinding. The slurry is returned to the fine slurry tank (22), and the overflow port of the fine slurry tank (22) is connected to the ultrafine slurry tank (24) through the twenty-seventh pipe (67). Step 9: The ultrafine slurry tank (24) enters the tenth centrifugal pump (39) through the thirty-first pipeline (71), and is then transported to the dewatered coarse coal kneader (7) through the thirty-second pipeline (72) to prepare gasification slurry; at the same time, it enters the eleventh centrifugal pump (40) through the thirty-third pipeline (73), and is then transported to the filter press fine coal kneader (18) through the thirty-fourth pipeline (74) to prepare filter press fine slurry; The coal slurry concentration in the ultrafine slurry tank (24) is 30-46%; Step 10: Water and additives are added to the dewatered coarse coal kneader (7), along with centrifugal coal conveyed by the centrifugal coal belt scale (6), ultrafine slurry conveyed from the 32nd pipeline (72), and filter slurry conveyed by the 21st pipeline (61) to prepare gasification coal slurry. The slurry is then fed into the low-pressure coal slurry tank (27) through a discharge chute and then transported to the chemical plant for gasification. The mass ratio of centrifuged coal, filter press slurry, additives, and ultrafine slurry used in the preparation of gasified coal slurry is 75:15:10:0.17; the mass concentration of the gasified coal slurry is 63-69%.

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