Automatic Coal Slurry Recycling System

Abstract

This utility model provides an automatic waste coal slurry recycling system, including a coal bunker, a weighing feeder, a mill, and a drum screen. The outlet of the coal bunker is fixedly connected to the inlet of the weighing feeder. The outlet of the weighing feeder is connected to the inlet of the mill through a pipe. The outlet of the mill is connected to the inlet of the drum screen. Coarse particles in the drum screen are discharged to the waste coal slurry dike through the coarse particle outlet and the waste coal slurry chute. The outlet of the waste coal slurry dike is connected to the inlet of the waste coal slurry tank through a trench. A variable frequency pump is installed in the waste coal slurry tank. The outlet of the variable frequency pump is connected in parallel to the middle section of the pipes of the weighing feeder and the mill through a pipe. An AI camera is also installed above the waste coal slurry dike to monitor the accumulation status of the waste coal slurry in the dike. The beneficial effects are: (1) automatic monitoring and flushing; (2) automatic return without manual adjustment; (3) full-chain parameter monitoring; (4) precise control of the variable frequency pump; (5) reduced equipment failure rate and energy consumption, and improved operation and maintenance economy.

Description

Technical Field

[0001] This utility model belongs to the field of coal-water slurry gasification technology, and in particular relates to an automatic waste coal slurry recycling system that recycles coarse particles and waste coal slurry generated in the coal slurry preparation system. Background Technology

[0002] In the coal-water slurry gasification process, the preparation of coal-water slurry through wet grinding of raw coal is the core step. The specific process is as follows: raw coal, process water, and additives are co-ground in a coal mill to obtain a coal slurry with a concentration of 60%-63%. The overflow coal slurry from the mill is separated by a drum screen; the qualified slurry flows into the mill outlet trough by gravity, is stirred and homogenized, and then pumped to the gasification section; while the waste coal slurry screened out needs to be recycled and treated.

[0003] The existing waste coal slurry recycling process still has the following shortcomings: (1) High dependence on manual labor: Operators need to manually flush the waste coal slurry of the cofferdam to the ditch 3 times a shift at 30-minute intervals, and then let it flow from the ditch to the waste coal slurry tank. Finally, the waste coal slurry is sent back to the mill inlet for recycling through the waste coal slurry pump. The flow rate of the waste coal slurry pump needs to be controlled by 2 people every 60 minutes per shift by manually adjusting the valve. (2) Low precision of manual control: The fluctuation range of flow rate adjusted by manual valve exceeds 20%, which causes the mill feed concentration to fluctuate beyond the standard value, affecting the stability of gas production in the gasifier; (3) High failure rate, high energy consumption and low efficiency: The load of the reuse system changes suddenly, and the equipment failure rate increases by 20%. At the same time, due to the long-term throttling operation of the power frequency pump, the energy loss is serious. The measured efficiency of the 45kW motor is only 52%; the power consumption for transporting 1 ton of waste coal slurry is 8.7kWh, which is 35% higher than the theoretical value. (4) Lack of liquid level linkage mechanism: Frequent start-up and shutdown of the pump at the power frequency (1450 r / min) reduces the service life of the impeller by 30% and results in high operation and maintenance costs. Summary of the Invention

[0004] To address the problems in the existing technology, this utility model provides an automatic waste coal slurry recycling system, including a coal bunker, a weighing feeder, a mill, and a drum screen. The outlet of the coal bunker is fixedly connected to the inlet of the weighing feeder. The outlet of the weighing feeder is connected to the inlet of the mill via a pipe. The outlet of the mill is connected to the inlet of the drum screen. Coarse particles in the drum screen are discharged to a waste coal slurry dike through a coarse particle outlet and a waste coal slurry chute. The outlet of the waste coal slurry dike is connected to the inlet of a waste coal slurry tank via a trench. A variable frequency pump is installed in the waste coal slurry tank. The outlet of the variable frequency pump is connected in parallel to the middle section of the pipes connecting the weighing feeder and the mill via a pipe. An AI camera is also installed above the waste coal slurry dike to monitor the accumulation status of the waste coal slurry within the dike.

[0005] In a preferred embodiment, the fine particles in the drum screen are discharged through the fine particle outlet to the inlet of the mill outlet trough, and the outlet of the mill outlet trough is connected to the inlet of the coal slurry trough through a low-pressure coal slurry pump and pipeline.

[0006] In a preferred embodiment, the weighing feeder is also equipped with a coal meter.

[0007] In a preferred embodiment, the weighing feeder is connected in parallel to a process water pipe, an additive pipe, and a low-pressure steam pipe near its outlet.

[0008] In a more preferred embodiment, control valves are provided on the process water pipe, the additive pipe, and the low-pressure steam pipe, and a process water flow meter is also provided on the process water pipe at the inlet of the control valve.

[0009] In a preferred embodiment, the outer perimeter of the waste coal slurry cofferdam is provided with a main flushing water pipe, which is divided into two branches. One branch is connected to several pipes in parallel at its end, and each pipe is equipped with a cofferdam flushing valve and a nozzle at its outlet. The other branch is also connected to several pipes in parallel, and the outlet of each pipe is located in a ditch, and the pipe is also equipped with a ditch flushing valve.

[0010] In a preferred embodiment, the waste coal slurry tank is also equipped with a radar level gauge and a stirrer.

[0011] In a preferred embodiment, the outlet pipe of the variable frequency pump is sequentially equipped with a variable frequency pump outlet valve and a waste coal slurry flow meter.

[0012] The beneficial effects of this utility model are: (1) The AI ​​camera above the waste coal slurry cofferdam monitors the accumulation status of waste coal slurry in real time. When the accumulation reaches the preset threshold, the cofferdam flushing valve of the main flushing water pipe is automatically opened, and the cofferdam is flushed in a directional manner through the nozzles, without the need for manual timed operation. At the same time, the flushing branch in the trench can automatically open the trench flushing valve to avoid waste coal slurry from accumulating and blocking in the trench, thus replacing manual dredging. (2) The variable frequency pump replaces the traditional manual valve adjustment and can automatically adjust the output flow according to the real-time data of the waste coal slurry flow meter and coal quantity meter, without the need for manual on-site valve operation; the number of manual personnel per shift is reduced from 2-3 people to 1 person (only periodic inspection is required), greatly reducing the labor intensity and avoiding the problem of insufficient timeliness of manual operation (such as the accumulation of cofferdam caused by leakage flushing). (3) The coal meter of the weighing feeder measures the amount of raw coal in real time, the process water flow meter of the process water pipe monitors the water volume, and the waste coal slurry flow meter feeds back the amount of coal. The three parameters are transmitted to the control system in a coordinated manner to form a closed loop of proportioning raw coal, process water and waste coal slurry. (4) The control system automatically adjusts the speed of the variable frequency pump according to the proportion requirements, replacing the traditional manual valve throttling adjustment, and the flow fluctuation range is greatly reduced; the mill feed concentration can be stably maintained in the standard range, avoiding the problem of sudden changes in mill load and unstable gas production of gasifier caused by concentration fluctuation, and the fluctuation range of gas production of gasifier is reduced. (5) The variable frequency pump can adjust the speed according to the actual flow demand, avoiding the energy waste caused by valve throttling while the fixed frequency pump is running at full load. The motor efficiency is improved and the energy consumption is greatly reduced. The radar level gauge monitors the liquid level of the waste coal slurry tank in real time, realizing the variable frequency pump to start and stop on demand and adjust the speed smoothly. It replaces the frequent start and stop of the existing fixed frequency pump, extends the impeller service life, reduces the equipment failure rate, and reduces the operation and maintenance cost. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0014] In the diagram: 1. Coal bunker; 2. Weighing feeder; 3. Process water pipe; 4. Process water flow meter; 5. Additive pipe; 6. Low-pressure steam pipe; 7. Mill; 8. Rotary drum screen; 9. Waste coal slurry chute; 10. Mill outlet trough; 11. AI camera; 12. Low-pressure coal slurry pump; 13. Flushing water main pipe; 14. Coal dam flushing valve; 15. Nozzle; 16. Waste coal slurry coal dam; 17. Ditch; 18. Ditch flushing valve; 19. Waste coal slurry tank; 20. Radar level gauge; 21. Agitator; 22. Variable frequency pump; 23. Variable frequency pump outlet valve; 24. Waste coal slurry flow meter; 25. Coal meter. Detailed Implementation

[0015] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0016] Example like Figure 1 The waste coal slurry automatic recycling system shown includes a coal bunker 1, a weighing feeder 2, a mill 7, and a drum screen 8. The outlet of the coal bunker 1 is fixedly connected to the inlet of the weighing feeder 2. The outlet of the weighing feeder 2 is connected to the inlet of the mill 7 via a pipe. The outlet of the mill 7 is connected to the inlet of the drum screen 8. Coarse particles in the drum screen 8 are discharged to the waste coal slurry dike 16 through the coarse particle outlet and the waste coal slurry chute 9. The outlet of the waste coal slurry dike 16 is connected to the inlet of the waste coal slurry tank 19 via a trench 17. The waste coal slurry tank 19 is equipped with a variable frequency pump 22. The outlet of the variable frequency pump 22 is connected in parallel to the middle section of the pipes connecting the weighing feeder 2 and the mill 7 via a pipe. An AI camera 11 is also installed above the waste coal slurry dike 16 to monitor the accumulation status of the waste coal slurry within the dike.

[0017] Furthermore, the fine particles in the drum screen 8 are discharged through the fine particle outlet to the inlet of the mill outlet trough 10, and the outlet of the mill outlet trough 10 is connected to the inlet of the coal slurry trough through the low-pressure coal slurry pump 12 and pipeline.

[0018] Furthermore, the weighing feeder 2 is also equipped with a coal meter 25.

[0019] Furthermore, the weighing feeder 2 is connected in parallel to a process water pipe 3, an additive pipe 5, and a low-pressure steam pipe 6 near its outlet.

[0020] Furthermore, control valves are provided on the process water pipe 3, additive pipe 5, and low-pressure steam pipe 6, and a process water flow meter 4 is also provided on the process water pipe 3 at the inlet of the control valve.

[0021] Furthermore, a flushing water main pipe 13 is provided around the waste coal slurry cofferdam 16. The flushing water main pipe 13 is divided into two branches. One branch is connected to several pipes in parallel at the end. Each pipe is equipped with a cofferdam flushing valve 14 and a nozzle 15 at the pipe outlet. The other branch is also connected to several pipes in parallel. The outlet of each pipe is located in the trench 17 and a trench flushing valve 18 is provided on the pipe.

[0022] Furthermore, the waste coal slurry tank 19 is also equipped with a radar level gauge 20 and a stirrer 21.

[0023] Furthermore, the outlet pipe of the variable frequency pump 22 is sequentially equipped with a variable frequency pump outlet valve 23 and a waste coal slurry flow meter 24.

[0024] Core system hardware configuration: AI camera: Hikvision DS-2CD3 camera (1920×1080 resolution, 30fps), equipped with ResNet-18 model (98.6% recognition accuracy), accurately identifies the amount of waste coal accumulation; Cofferdam flushing valve: DN30 pneumatic ball valve; Ditch flushing valve: DN50 pneumatic ball valve; Variable frequency pump: The ABB ACS880 frequency converter is equipped with a 45kW motor with an overload capacity of 150%.

[0025] The operation process is as follows: Raw materials are fed into the weighing feeder 2 through the coal bunker 1. The amount of raw materials fed into the feeder is quantitatively controlled by the coal meter 25. The weighing feeder 2 then sends the raw materials into the mill 7 through the pipeline for grinding. At the same time, process water, additives and low-pressure steam are added to the mill 7 through the process water pipe 3, the additive pipe 5 and the low-pressure steam pipe 6 for grinding. The raw materials overflowing after grinding enter the drum screen 8 for screening. The qualified coal slurry enters the mill outlet tank 10 for temporary storage, and then is pumped to the coal slurry tank by the low-pressure coal slurry pump 12 for subsequent processing. Waste coal slurry is put into the waste coal slurry cofferdam 16 through the waste coal slurry chute 9. When the AI ​​camera 11 recognizes that the waste coal slurry has accumulated on the steel grating cover plate of the ditch 17, it sends a signal to the control system to automatically open the cofferdam flushing valve 14 to flush the waste coal slurry into the ditch 17. At the same time, the ditch flushing valve 17 is opened to flush the waste coal slurry in the ditch into the waste coal slurry tank 19. The flushing flow rate is 100L / min and the flushing time is 5 minutes.

[0026] When the radar level gauge 20 detects that the waste coal slurry tank level reaches 80%, it sends a signal to the control system to start the waste coal slurry variable frequency pump 22, pumping the waste coal slurry into the mill 7. At the same time, the control system starts to calculate the coal-water ratio and automatically adjusts the process water flow rate and the waste coal slurry variable frequency pump to match the amount of raw coal, process water, and waste coal slurry added. The matching is performed according to the following logic: when the radar level gauge 20 is greater than 80%, the waste coal slurry variable frequency pump 22 adjusts its frequency according to f=30+18×(H-80%)^{0.7}, where f is the frequency of the variable frequency pump, × is the running time of the variable frequency pump, and H is the percentage height of the liquid level. When the liquid level of radar level gauge 20 is less than 30%, shut down waste coal slurry variable frequency pump 22 and reset process water flow rate to 24 m³ / h.

[0027] In the process of reusing waste coal slurry: Waste coal slurry: contains 30% dry coal + 70% water; Process water: The total coal-water ratio of the system must be maintained at dry coal:water = 1:3; Based on actual parameters: Raw coal quantity = 72t / h (dry basis), waste coal slurry flow rate = 10m³ / h (of which the concentration ratio is 30% dry coal and 70% water), waste coal slurry dry coal quantity = 3t / h, total dry coal quantity of the system = (72+3)t / h, total water requirement of the system = 75÷3 = 25m³ / h (maintaining coal-water ratio = 3:1), waste coal slurry self-contained water quantity = 10*0.7 = 7m³ / h, process water compensation quantity = 25-7 = 18m³ / h.

[0028] After our company applied this utility model, the flow fluctuation was reduced from ±20.3% to ±2.7%, an improvement rate of 86.7%; the impeller life was reduced from 12 months to 24 months, an improvement rate of 100%; and the manual intervention time was reduced from 7 man-hours / day to 0 man-hours / day, an improvement rate of 100%.

Claims

1. An automatic waste coal slurry recycling system, characterized in that, The system includes a coal bunker (1), a weighing feeder (2), a mill (7), and a drum screen (8). The outlet of the coal bunker (1) is fixedly connected to the inlet of the weighing feeder (2). The outlet of the weighing feeder (2) is connected to the inlet of the mill (7) through a pipe. The outlet of the mill (7) is connected to the inlet of the drum screen (8). Coarse particles in the drum screen (8) are discharged to the waste coal slurry chute (9) through the coarse particle outlet. The outlet of the waste coal slurry dam (16) is connected to the inlet of the waste coal slurry tank (19) through a trench (17). A variable frequency pump (22) is installed in the waste coal slurry tank (19). The outlet of the variable frequency pump (22) is connected in parallel to the middle section of the pipes of the weighing feeder (2) and the mill (7) through a pipe. An AI camera (11) is also installed above the waste coal slurry dam (16) to monitor the accumulation status of waste coal slurry in the dam.

2. The automatic waste coal slurry recycling system according to claim 1, characterized in that, The fine particles in the drum screen (8) are discharged through the fine particle outlet to the inlet of the mill outlet trough (10). The outlet of the mill outlet trough (10) is connected to the inlet of the coal slurry trough through a low-pressure coal slurry pump (12) and a pipeline.

3. The automatic waste coal slurry recycling system according to claim 1, characterized in that, The weighing feeder (2) is also equipped with a coal meter (25).

4. The automatic waste coal slurry recycling system according to claim 1, characterized in that, The weighing feeder (2) is connected in parallel to a process water pipe (3), an additive pipe (5), and a low-pressure steam pipe (6) near its outlet.

5. The automatic waste coal slurry recycling system according to claim 4, characterized in that, Control valves are provided on the process water pipe (3), additive pipe (5) and low-pressure steam pipe (6), and a process water flow meter (4) is also provided on the process water pipe (3) at the inlet of the control valve.

6. The automatic waste coal slurry recycling system according to claim 1, characterized in that, The waste coal slurry cofferdam (16) is surrounded by a main flushing water pipe (13). The main flushing water pipe (13) is divided into two branches. One branch is connected to several pipes in parallel at the end. Each pipe is equipped with a cofferdam flushing valve (14) and a nozzle (15) at the outlet of the pipe. The other branch is also connected to several pipes in parallel. The outlet of each pipe is located in a ditch (17) and a ditch flushing valve (18) is also provided on the pipe.

7. The automatic waste coal slurry recycling system according to claim 1, characterized in that, The waste coal slurry tank (19) is also equipped with a radar level gauge (20) and a stirrer (21).

8. The automatic waste coal slurry recycling system according to claim 1, characterized in that, The variable frequency pump (22) is equipped with a variable frequency pump outlet valve (23) and a waste coal slurry flow meter (24) in sequence on its outlet pipe.

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