Dry quenching fly ash recycling and reusing injection system

Abstract

The utility model discloses a dry quenching dedusting ash recycling and reusing injection system which comprises a dry quenching dedusting ash storage bin, a rotary valve, a pneumatic injection conveying system, a conveying pipeline and a mill feeding device, an outlet in the lower portion of the dry quenching dedusting ash storage bin is connected with an inlet of the rotary valve, and an outlet of the rotary valve is connected with an online injector. The online ejector comprises a solid material inlet, a gas inlet and a gas-solid mixture ejection opening, the solid material inlet is connected with the rotary valve outlet, the gas inlet is connected with one end of the gas conveying pipeline, and the gas-solid mixture ejection opening is connected with one end of the mixture conveying pipeline; an outlet of the mixture conveying pipeline is connected with at least one mill coal dropping pipe of the coal injection station, and a mill feeding device is arranged at the mill coal dropping pipe; the rotary valve comprises a rotor and a shell, the shell is provided with a feeding port and a discharging port, the rotor is arranged in the shell and located between the feeding port and the discharging port, and the gap between the rotor and the shell is smaller than 0.8 mm.

Description

Technical Field

[0001] The utility model belongs to the technical field of coking and steel, and relates to a dry quenching dust recovery and reuse injection system. Background Art

[0002] Coke dry quenching (CDQ) dust is the environmental dust from the dry quenching of coke in coking plants. It is a waste product generated by the coking industry's environmental protection, energy conservation, and clean production requirements. The CDQ production process produces a large amount of CDQ dust. It is primarily divided into two types: the first type is dusted coke dust generated by CDQ dust removal equipment, and the second type is dusted coke dust generated by dust removal equipment in the coke storage and coke cutting room. To ensure environmental protection and reduce resource waste, some of this dust is currently used in blast furnaces to replace pulverized coal (BFI) due to its high fixed carbon content and calorific value. The most popular treatment method is to add a drop hopper above the raw coal conveyor. The CDQ dust is then fed onto the raw coal conveyor and fed into the mill along with the coal. After mixing with pulverized coal, it is injected into the blast furnace through the blast furnace injection system for combustion.

[0003] However, due to the relatively small density and particle size of CDQ dust, adding it to the belt conveyor generates significant secondary dust. This wastes some of the CDQ dust and creates environmental pollution and harms personnel health. Therefore, the question of how to completely enclose and harmlessly recycle CDQ dust has become crucial. Summary of the Invention

[0004] The purpose of the utility model is to solve the above problems and provide a CDQ dust recovery and reuse blowing system, which realizes the completely enclosed recovery and reuse of CDQ dust, and meets the environmental protection treatment requirements while generating certain economic benefits.

[0005] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0006] A CDQ dust ash recovery and reuse blowing system includes a CDQ dust ash storage bin, a rotary valve, a pneumatic blowing conveying system and conveying pipeline, and a mill blanking device.

[0007] The outlet at the bottom of the CDQ dust storage bin is connected to the inlet of the rotary valve, and the outlet of the rotary valve is connected to the online ejector of the pneumatic blowing conveying system.

[0008] The online ejector comprises a solid material inlet, a gas inlet and a gas-solid mixture ejection outlet, wherein the solid material inlet is connected to the rotary valve outlet, the gas inlet is connected to one end of the gas delivery pipeline, and the gas-solid mixture ejection outlet is connected to one end of the mixture delivery pipeline;

[0009] The pneumatic blowing air flow conveying device of the pneumatic blowing conveying system is arranged on the gas conveying pipeline;

[0010] The outlet of the mixture conveying pipeline is connected to at least one coal injection station mill coal drop pipe, and each mill coal drop pipe is connected to a mill feeding device, which includes a blow pipe connecting short pipe, a mill pipe and a top cover. The inlet of the blow pipe connecting short pipe is connected to the outlet of the mixture conveying pipeline, and the outlet of the blow pipe connecting short pipe is connected to the inlet of the mill pipe. The upper opening of the mill pipe is connected to the top cover, and a wear-resistant baffle is connected below the top cover. The surface of the wear-resistant baffle opposite to the mill pipe inlet is an arc surface, and the angle between the inclined drop surface of the mill pipe and the mill coal drop pipe is 45°. The outlet of the mill pipe is connected to the mill coal drop pipe flange fitting.

[0011] The rotary valve includes a rotor and a shell, on which a feed port and a discharge port are arranged. The rotor connected to a driving device is arranged in the shell between the feed port and the discharge port. The gap between the rotor and the shell is less than 0.8 mm, and a wear-resistant coating is sprayed on the shell and the rotor.

[0012] The rotary valve includes a rotor and a shell, on which a feed port and a discharge port are arranged. The rotor connected to a driving device is arranged in the shell between the feed port and the discharge port. The gap between the rotor and the shell is less than 0.8 mm. Due to the strong abrasiveness of CDQ powder, a wear-resistant coating is sprayed on the shell and the rotor.

[0013] The rotor and the housing are both made of carbon steel, and the parts in contact with the material are sprayed with a tungsten carbide wear-resistant layer.

[0014] The CDQ ash storage bin is provided with a nitrogen fluidization port to allow nitrogen to flow in and seal the bin.

[0015] A compressed nitrogen interface is provided at the shaft seal of the rotary valve to seal with nitrogen.

[0016] The gap between the rotor and the housing of the rotary valve is 0.3-0.5 mm.

[0017] The rotary valve is connected to a frequency converter.

[0018] The pneumatic blowing air flow conveying device comprises a gas storage tank, a pressure reducing valve, a pneumatic shut-off valve, a gas flow meter, a flow regulating valve and a pressure transmitter which are sequentially arranged on a gas conveying pipeline.

[0019] The beneficial effects of the present invention include: a rotary valve provided at the discharge port of the CDQ dust storage bin, creating a small gap between the rotor and the housing, providing a gas-locking function. Furthermore, a nitrogen gasification port is provided in the CDQ dust storage bin to allow nitrogen gas to flow in, and a compressed nitrogen port is provided at the shaft seal of the rotary valve to facilitate nitrogen sealing. These measures ensure safe CDQ dust recovery and reuse, effectively preventing damage to personnel and equipment. A flow control device is provided in the gas delivery pipeline, allowing the airflow and pressure of the CDQ dust injection to be flexibly adjusted according to the number of mills and grinding capacity, ensuring that the CDQ and dust are thoroughly mixed in a set ratio without affecting blast furnace production. Furthermore, a mill discharge device is added to prevent CDQ dust from abrading the mill coal drop pipe. The injection system provided by the present invention recycles and reuses CDQ dust, preventing environmental pollution from CDQ dust, and achieving significant environmental benefits, achieving both economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] FIG1 is a schematic structural diagram of the CDQ dust recovery and reuse injection system provided by the present invention.

[0021] Figure 2 This is a structural schematic diagram of the coal drop pipe of the mill provided by the utility model.

[0022] in:

[0023] 1. CDQ dust storage silo, 2. Gas storage tank, 3. Pressure reducing valve, 4. Pneumatic shut-off valve, 5. Gas flowmeter, 6. Flow control valve, 7. Pressure transmitter, 8. Rotary valve, 9. In-line injector, 10A. Gas delivery pipeline, 10B: Mixture delivery pipeline, 11: Gate valve, 12: Mill feed device, 13: Mill coal drop pipe. 21. Injection pipe connecting short pipe, 20: Mill pipe, 22. Top cover, 23. Wear-resistant baffle, 24. Inclined drop surface, 25. Flange fittings. DETAILED DESCRIPTION

[0024] First, please refer to Figure 1, which is a preferred embodiment of the present invention. The specific structure and implementation method are as follows:

[0025] like Figure 1As shown, a CDQ dust recovery and reuse blowing system of the present invention comprises a CDQ dust storage bin 1, a rotary valve 8, a pneumatic blowing conveying system and a conveying pipeline. The outlet of the lower portion of the CDQ dust storage bin 1 is connected to the inlet of the rotary valve 8, and the outlet of the rotary valve 8 is connected to an online ejector 9 of the pneumatic blowing conveying system. The online ejector 9 comprises a solid material inlet, a gas inlet and a gas-solid mixture ejection outlet. The solid material inlet is connected to the outlet of the rotary valve, the gas inlet is connected to one end of the gas conveying pipeline, and the gas-solid mixture ejection outlet is connected to one end of the mixture conveying pipeline. The pneumatic blowing airflow conveying device of the pneumatic blowing conveying system is arranged on the gas conveying pipeline 10A. The outlet of the mixture conveying pipeline 10B is connected to at least one mill feed device 12 connected to a coal drop pipe 13 of a mill in a coal injection station. The mill feed device 12 is connected to a coal drop pipe 13 of a mill in a coal injection station. The device 12 is connected to the mill coal drop pipe 13 through a flange pipe fitting 25; the mill feeding device includes a blow pipe connecting short pipe 21, a mill pipe 20 and a top cover 22, the inlet of the blow pipe connecting short pipe 21 is connected to the outlet of the mixture conveying pipeline 10B, the outlet of the blow pipe connecting short pipe 21 is connected to the inlet of the mill pipe 20, the upper opening of the mill pipe is connected to the top cover 22, and a wear-resistant baffle 23 is connected below the top cover. The surface of the wear-resistant baffle 23 opposite to the mill pipe inlet is an arc surface, the inclined drop surface 24 of the mill pipe 20 forms an angle of 45° with the mill coal drop pipe 13, and the outlet of the mill pipe is connected to the mill coal drop pipe flange fitting 25.

[0026] The rotary valve includes a rotor and a shell, on which a feed port and a discharge port are arranged. The rotor connected to a driving device is arranged in the shell between the feed port and the discharge port. The gap between the rotor and the shell is less than 0.8 mm. Due to the strong abrasiveness of CDQ powder, a wear-resistant coating is sprayed on the shell and the rotor.

[0027] Specifically, the injection pipe connecting short circuit 21 is flange-connected to the mixture delivery pipeline 10B, forming the feed portion of the device. After entering through the mixture delivery pipeline 10B, the CDQ powder collides with the wear-resistant baffle 23 and changes direction. The wear-resistant baffle is responsible for changing the feeding direction of the CDQ powder to avoid wear on the mill coal drop pipe, and is generally made of ceramic or bimetallic wear-resistant materials. Due to the high abrasiveness of CDQ powder, it needs to be replaced regularly. The wear-resistant baffle 23 and the top cover 22 are bolted together into one body. During maintenance and replacement, the wear-resistant baffle 23 can be repaired and replaced without disassembling the entire mill coal drop pipe. After the CDQ powder flow changes direction and slows down after passing through the wear-resistant baffle 23, most of it directly enters the mill coal drop pipe. Due to the deceleration, it will not be directly sprayed onto the inner wall of the mill coal drop pipe and cause wear. The other part collides with the inclined drop surface 24 at the bottom of the drop device, slows down again, and changes direction to enter the mill coal drop pipe. Since the inclined blanking surface 24 directly collides and rubs with the CDQ powder, the inclined blanking surface is also made of ceramic or bimetallic wear-resistant material; preferably, in order to ensure that most of the CDQ powder enters the mill coal drop pipe and does not accumulate in the mill feed device, the angle between the inclined blanking surface and the mill coal drop pipe is 45 degrees;

[0028] In order to facilitate the connection between the mill coal drop pipe 13 and the CDQ powder injection system, a flange pipe fitting 25 is provided on the mill coal drop pipe to connect with the mill coal drop pipe. The mill feeding device and the mill coal drop pipe are connected by flanges and bolts without leakage or dust.

[0029] Specifically, CDQ dust silo 1 is a storage facility used to store recycled CDQ dust. CDQ dust is typically transported to CDQ dust silo 1 using pneumatic conveying or a suction tank truck. To prevent hazardous contact between CDQ dust and air, the CDQ dust silo is sealed using nitrogen fluidization. CDQ dust silo 1 is typically atmospheric pressure equipment. To ensure continuous injection of CDQ dust, a sufficient amount of CDQ dust is typically stored in CDQ dust silo 1.

[0030] Specifically, the bottom ash outlet of the CDQ dust ash storage bin 1 is connected to a rotary valve. To smoothly inject the CDQ dust ash into the mill coal drop pipe without leaking gas from the rotary valve into the CDQ dust ash storage bin, a rotary valve 8 is installed at the CDQ dust ash storage bin outlet. This rotary valve 8 is an improvement on the structure of existing rotary valves, such as a modified star-shaped ash discharge valve. The main modification is to reduce the gap H between the rotor and the housing. This gap is generally less than 0.8mm. The gap H between the rotor and the housing of the rotary valve 8 is preferably 0.3 to 0.5mm. This allows the rotary valve to effectively lock in air, preventing the injected compressed gas from entering the CDQ dust ash storage bin 1 and causing poor ash discharge or clogging of the injection pipeline. The gap before the modification was 2mm.

[0031] Because CDQ dust is hard and highly abrasive, the rotary valve rotor and housing are constructed of carbon steel, and the material-contacting parts are sprayed with wear-resistant materials such as tungsten carbide. The inlet of rotary valve 8 is connected to the ash outlet of CDQ dust silo 1. A gate valve 11 is installed between rotary valve 8 and the outlet of CDQ dust silo 1 to shut off the CDQ dust for maintenance in the event of a rotary valve failure. Rotary valve 8 is connected to a frequency converter (VFD) housed in an MCC (Motor Control Center) cabinet, which regulates speed to accommodate varying injection volumes and the amount of air injected into the mill.

[0032] Specifically, the pneumatic injection conveying system includes an online injector 9, a pneumatic airflow conveying device, and a gas conveying pipeline. The gas-solid mixture outlet of the online injector 9 is connected to the mixture conveying pipeline. The online injector 9 is a device that accelerates the mixing of the injected gas and the CDQ dust, ensuring a uniform mixing of the gas and dust to prevent interruptions in the injection flow or pipeline blockage. The online injector 9 has three interfaces: a solid material inlet, a gas inlet, and a gas-solid mixture outlet. The solid material inlet is connected to the outlet of the rotary valve. The gas inlet is connected to the compressed gas source, namely the gas compressor, through a gas conveying pipeline. The gas-solid mixture outlet is connected to the mill coal chute through the mixture conveying pipeline. The CDQ dust exits the bottom outlet of the CDQ dust silo, enters the rotary valve, and then mixes with the compressed gas through the online injector 9. It then enters the mill coal chute through the mixture conveying pipeline. After being fully ground and mixed with the raw coal in the mill, it enters the pulverized coal bin and finally enters the blast furnace through the coal injection system for combustion.

[0033] The pneumatic blowing and conveying device is a power source for pneumatically conveying the CDQ dust removal ash through an online ejector 9 into the incineration equipment. In this embodiment, the pneumatic blowing and conveying device includes a gas compressor (not shown), a gas storage tank 2, a pressure reducing valve 3, a pneumatic shut-off valve 4, a gas flow meter 5, a flow regulating valve 6, and a pressure transmitter 7, which are sequentially connected to a gas conveying pipeline.

[0034] To achieve automatic control, the present invention is connected to a PLC control system. This PLC control system controls the rotary valve, the drive devices, and the valves in the pneumatic injection conveying system. The pressure reducing valve 3 is a gas source pressure reducing device used to reduce the gas source pressure to the pressure required for injection. The pneumatic switching valve 4 is a flow cutoff device for gas injection. The gas flow meter 5 and pressure transmitter 7 monitor the injection gas parameters. Based on the monitored data, the PLC control system adjusts the flow control device and related valves.

[0035] The present invention utilizes a gas compressor, and a flow control valve 6 allows for the adjustment of gas volume and pressure based on the flow and pressure detected by a gas flow meter 5 and a pressure transmitter 7. A gas storage tank 2 is provided as an energy storage device for the gas required for injection. Fluctuations in the gas source of the pneumatic injection conveying device during the injection process can be regulated by the gas storage tank 2, ensuring that the entire injection process is free from malfunctions due to external gas sources or other equipment. The compressed gas can be an inert gas, such as the aforementioned nitrogen, or another inert gas.

[0036] In actual operation, there are many situations such as injecting CDQ dust into the coal drop pipes of different mills, with different injection volumes and different numbers of injection mills. By adjusting the injection flow rate through a pneumatic injection airflow conveying device including a flow control device, the injection flow rate is adjusted to prevent pipe blockage caused by too little gas volume, and to avoid wear of pipes and elbows and energy waste caused by too much gas volume. In other words, the goal of meeting production needs while saving energy and protecting the environment can be achieved. The conveying pipeline is generally made of seamless steel pipe or seamless steel pipe lined with ceramic or other wear-resistant materials.

[0037] The working process of the CDQ dust recovery and reuse injection system of the utility model is as follows:

[0038] 1. The pressure reducing valve 3 has been set to the required injection pressure;

[0039] 2. The operator selects the mill that needs to be sprayed, sets the required spraying volume, and then starts the PLC control system;

[0040] 3. The pneumatic shut-off valve 4 on the gas delivery pipeline is opened, and the flow control valve 6 automatically adjusts the gas volume according to the feedback from the flow meter 5 and pressure transmitter 7 and the number of selected mills to start pipeline cleaning;

[0041] 4. After a set purge delay, the rotary injection valve 8 is activated. The CDQ dust is accelerated by the rotary injection valve 8 through the online injector 9 and enters the mixture conveying pipeline. Then, it is evenly injected into the mill coal drop pipe under the action of the injection gas.

[0042] 5. At the same time, the control system continuously adjusts the rotation speed of the rotary injection valve through the frequency converter according to the weight change of the CDQ dust storage bin 1, so that the actual injection volume is infinitely close to the injection volume set by the operator;

[0043] 6. The operator can adjust the injection volume or the number of mills at any time. At this time, the control system automatically adjusts the required injection flow through the flow control valve 6 to adapt to the new injection working conditions;

[0044] 7. If the operator issues a command to stop the spraying, rotary valve 8 stops and the pipeline is then purged. If the stop is temporary, pneumatic shut-off valve 4 remains open, and flow control valve 6 adjusts the air volume to continuously purge the pipeline. After the temporary stop, the operator can restart rotary valve 8 at any time as needed. If the entire system needs to be stopped, pneumatic shut-off valve 4 will close after a certain period of purging the pipeline, and the entire spraying system will stop.

[0045] 8. This utility model is operated through a PLC control system, which features precise operation and a high safety factor. The recycling and reuse of CDQ dust has significant environmental, economic, and social benefits, effectively avoiding injury to workers and equipment, as well as environmental pollution.

[0046] The PLC control system and the connection with the corresponding components in this system are all existing technologies, so they are not described here in detail.

Claims

1. A CDQ dust recovery and reuse injection system, characterized by: It includes a dry quenching dust storage bin, a rotary valve, a pneumatic injection conveying system and conveying pipelines, and a mill coal drop pipe; The outlet at the lower part of the CDQ dust storage bin is connected to the inlet of the rotary valve, and the outlet of the rotary valve is connected to the online ejector of the pneumatic blowing conveying system; The online ejector comprises a solid material inlet, a gas inlet and a gas-solid mixture ejection outlet, wherein the solid material inlet is connected to the rotary valve outlet, the gas inlet is connected to one end of the gas delivery pipeline, and the gas-solid mixture ejection outlet is connected to one end of the mixture delivery pipeline; The pneumatic blowing air flow conveying device of the pneumatic blowing conveying system is arranged on the gas conveying pipeline; The outlet of the mixture conveying pipeline is connected to at least one coal injection station mill coal drop pipe, and a mill feeding device is provided at each mill coal drop pipe; the mill feeding device includes a blow pipe connecting short pipe, a mill pipe and a top cover, the inlet of the blow pipe connecting short pipe is connected to the outlet of the mixture conveying pipeline, the outlet of the blow pipe connecting short pipe is connected to the inlet of the mill pipe, the upper opening of the mill pipe is connected to the top cover, and a wear-resistant baffle is connected below the top cover, the surface of the wear-resistant baffle facing the mill pipe inlet is an arc surface, and the angle between the inclined drop surface of the mill pipe and the mill coal drop pipe is 45 degrees; The rotary valve includes a rotor and a shell, on which a feed port and a discharge port are arranged. The rotor connected to a driving device is arranged in the shell between the feed port and the discharge port. The gap between the rotor and the shell is less than 0.8 mm, and a wear-resistant coating is sprayed on the shell and the rotor.

2. The CDQ dust recovery and reuse injection system according to claim 1 is characterized by: The rotor and the housing are both made of carbon steel, and the parts in contact with the material are sprayed with a tungsten carbide wear-resistant layer.

3. The CDQ dust recovery and reuse system according to claim 1 is characterized by: The CDQ ash storage bin is provided with a nitrogen fluidization port to allow nitrogen to flow in and seal the bin.

4. The CDQ dust recovery and reuse system according to claim 1 or 3, characterized in that: A compressed nitrogen interface is provided at the shaft seal of the rotary valve to seal with nitrogen.

5. The CDQ dust recovery and reuse injection system according to claim 1 is characterized by: The gap between the rotor and the housing of the rotary valve is 0.3-0.5 mm.

6. The CDQ dust recovery and reuse injection system according to claim 5 is characterized by: The rotary valve is connected to a frequency converter.

7. The CDQ dust recovery and reuse injection system according to claim 1, 5 or 6, characterized in that: The pneumatic blowing air flow conveying device comprises a gas storage tank, a pressure reducing valve, a pneumatic shut-off valve, a gas flow meter, a flow regulating valve and a pressure transmitter which are sequentially arranged on a gas conveying pipeline.

Images