Closed calcium carbide purification ash recycling system and its usage method

Abstract

The present invention provides a closed calcium carbide purification ash recycling system and a method for using the same, which relates to the technical field of calcium carbide, and solves the technical problem that a large amount of slag is generated after the purification ash is burned in the existing purification ash recycling device, and the secondary treatment increases the cost and pollutes the environment. The closed calcium carbide purification ash recycling system includes a purification ash storage device, a pneumatic injection device, a gas source device, and a purification ash combustion device; wherein, the outlet of the purification ash storage device is communicated with the inlet of the pneumatic injection device, and the outlet of the pneumatic injection device and the outlet of the gas source device are both communicated with the inlet of the purification ash combustion device so that the purification ash and the gas blown in by the gas source device can be mixed and burned in the purification ash combustion device to make cement. The present invention is used to provide a closed calcium carbide purification ash recycling system and a method for using the same, which can burn the purification ash to make cement for secondary utilization, save the treatment cost, and prevent environmental pollution.

Description

Technical Field

[0001] The present invention relates to the technical field of calcium carbide, and in particular to a closed calcium carbide purification ash recycling system and a method for using the same. Background Art

[0002] The tail gas generated by a closed calcium carbide furnace contains 50 - 150 g / Nm3 of dust, which generally needs to be treated by a purification device and then treated as solid waste. When purifying and treating, the tail gas first enters a sedimentation tank to settle 40% - 50% of the large - particle dust, then is cooled and dedusted by an air - cooler, and then enters a bag - type dust collector for fine filtration. The solid dust collected by the sedimentation tank, the air - cooler, and the bag - type dust collector is generally called purification dust (abbreviated as purification ash). Currently, the main treatment method for purification ash is landfill. However, the ash contains relatively high amounts of calcium oxide, magnesium, alkalis, and cyanide, etc. During the landfill transfer process, spontaneous combustion and other situations are likely to occur, causing injury to personnel or damage to equipment. At the same time, landfill will also cause serious environmental pollution and waste of resources.

[0003] Recently, a purification ash recycling device has emerged. The purification ash is directly sprayed into a fluidized - bed furnace for combustion. Although the problem of spontaneous combustion of purification ash is solved, after the purification ash is directly sprayed into the fluidized - bed furnace for combustion, it will directly adhere to the furnace wall of the fluidized - bed furnace and needs to be cleaned regularly. Moreover, after the fluidized - bed furnace burns the purification ash, a large amount of slag increases, and the secondary treatment of the slag will also increase costs and pollute the environment. Summary of the Invention

[0004] The purpose of the present invention is to provide a closed calcium carbide purification ash recycling system and a method for using the same, so as to solve the technical problem in the prior art that a large amount of slag is generated after the purification ash recycling device burns the purification ash, and the secondary treatment increases costs and pollutes the environment. The many technical effects that can be produced by the preferred technical solutions among the many technical solutions of the present invention are described in detail below.

[0005] To achieve the above - mentioned purpose, the present invention provides the following technical solutions:

[0006] The closed calcium carbide purification ash recycling system provided by the present invention includes a purification ash storage device, a pneumatic injection device, a gas source device, and a purification ash combustion device; wherein,

[0007] The outlet of the purification ash storage device is connected to the inlet of the pneumatic injection device, and the outlet of the pneumatic injection device and the outlet of the gas source device are both connected to the inlet of the purification ash combustion device, so that the purification ash and the gas blown in by the gas source device can be mixed in the purification ash combustion device;

[0008] The purification ash combustion device includes a feeding device, a burner, and a preheater; the outlet of the pneumatic injection device and the outlet of the gas source device are both connected to the feeding device, the outlet of the feeding device is connected to the inlet of the burner, and the outlet of the burner extends into the preheater so that the purification ash can be burned in the preheater to make cement.

[0009] In a preferred or alternative embodiment, the feeding device includes a discharge pipeline, a distributor, and at least two feeding pipelines; the outlet of the pneumatic injection device and the outlet of the gas source device are both connected to the discharge pipeline, the outlet of the discharge pipeline is connected to the distributor, the distributor includes at least two outlets connected to its inlet, and each outlet of the distributor is respectively connected to a feeding pipeline; the number of burners is at least two, and each outlet of the distributor is connected to one of the burners.

[0010] In a preferred or alternative embodiment, the outlets of at least two burners are evenly distributed along the circumference of the preheater, and each burner outlet is located in the same plane and the plane where it is located is perpendicular to the axis of the preheater.

[0011] In a preferred or alternative embodiment, the length of each feeding pipeline is equal.

[0012] In a preferred or alternative embodiment, the pneumatic injection device includes a feeding pipeline, a blowing tank, and a rotary feeder; the feeding pipeline can connect the purification ash storage device and the blowing tank, a rotary feeder is arranged at the outlet of the blowing tank, and the outlet of the rotary feeder is connected to the feeding device;

[0013] An inspection isolation valve, a pneumatic isolation valve, and a blowing tank inlet valve are serially arranged on the feeding pipeline.

[0014] In a preferred or alternative embodiment, the pneumatic injection device further includes a fluidization pressurization gas path, the inlet of the fluidization pressurization gas path is connected to an external nitrogen source, and the outlet is connected to the blowing tank.

[0015] In a preferred or alternative embodiment, the pneumatic injection device further includes a weighing and metering device, and the weighing and metering device is connected to the blowing tank.

[0016] In a preferred or alternative embodiment, the pneumatic injection device further includes an exhaust device capable of discharging the gas in the blowing tank, and the exhaust device includes an exhaust dust collector and an exhaust valve arranged in series, and the exhaust dust collector is connected to the blowing tank.

[0017] In a preferred or alternative embodiment, the pneumatic injection device further includes a balancing device, which includes a balancing pipe and a balancing pneumatic valve. Both ends of the balancing pipe are respectively connected to the outlet of the rotary feeder and the upper region of the injection tank, and the balancing pneumatic valve is arranged on the balancing pipe.

[0018] A method for using the closed calcium carbide purification ash recycling system provided by any technical solution of the present invention includes the following steps:

[0019] Step A: Before use, start the gas source device to clean the pipeline and cool the combustion device. The rotary feeder stops, the maintenance isolation valve opens, and the pneumatic isolation valve, the injection tank inlet valve, the balancing pneumatic valve, and the exhaust valve close.

[0020] Step B: When starting to use, open the exhaust valve, close the balancing pneumatic valve. After reducing the pressure in the injection tank, sequentially open the injection tank inlet valve and the pneumatic isolation valve.

[0021] Step C: When the weighing and metering device detects that the injection tank is full of materials, sequentially close the injection tank inlet valve, the pneumatic isolation valve, and the exhaust valve, and open the fluidization and pressurization gas path.

[0022] Step D: When the pressure in the injection tank is not less than the pressure in the discharge pipeline, open the balancing pneumatic valve, start the rotary feeder to feed the purification ash into the discharge pipeline and enter the preheater through the burner for combustion.

[0023] Step E: When the weighing and metering device detects that the materials in the injection tank are insufficient, the rotary feeder operates, and repeat operation steps B to D.

[0024] Step F: After use, close the rotary feeder, and the gas source device closes after purging the pipeline.

[0025] Based on the above technical solution, the embodiments of the present invention can at least produce the following technical effects:

[0026] The closed calcium carbide purification ash recycling system provided by the present invention includes a purification ash storage device, a pneumatic injection device, a gas source device, and a purification ash combustion device. The purification ash storage device is used to store the purification ash to be recycled. The purification ash to be recycled is mixed with the gas blown by the pneumatic injection device and the gas source device from the purification ash storage device, enters the purification ash combustion device, and is fully combusted in the preheater through the burner to make cement, realizing the secondary utilization of the purification ash, and avoiding the increase in treatment cost and secondary pollution caused by the generation of slag during the combustion of the purification ash. Description of the Drawings

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0028] Figure 1 Schematic diagram of the closed calcium carbide purification ash recycling system provided by the present invention;

[0029] Figure 2 is Figure 1 Schematic diagram of the pneumatic injection equipment shown.

[0030] In the figure, 1 is the purification ash storage equipment; 2 is the pneumatic injection equipment; 21 is the feeding pipeline; 211 is the maintenance isolation valve; 212 is the pneumatic isolation valve; 213 is the injection tank inlet valve; 22 is the injection tank; 23 is the rotary feeder; 24 is the fluidization pressurization gas path; 25 is the weighing and metering device; 26 is the exhaust device; 261 is the dust collector; 262 is the exhaust valve; 27 is the balancing device; 271 is the balance pipe; 272 is the balance pneumatic valve; 3 is the gas source equipment; 4 is the purification ash combustion equipment; 41 is the feeding device; 411 is the discharge pipeline; 412 is the distributor; 413 is the conveying pipeline; 42 is the burner; 43 is the preheater. Detailed implementation manners

[0031] To make the purpose, technical solutions and advantages of the present invention clearer, the following will describe the technical solutions of the present invention in detail. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other implementation manners obtained by those of ordinary skill in the art without creative efforts belong to the scope protected by the present invention.

[0032] The present invention provides a closed calcium carbide purification ash recycling system and its usage method that can burn the purification ash to make cement for secondary utilization, saving the treatment cost and preventing environmental pollution.

[0033] The following Figures 1 to 2 will elaborate on the technical solutions provided by the present invention in more detail.

[0034] As Figures 1 to 2 shown, the closed calcium carbide purification ash recycling system provided by the present invention includes a purification ash storage equipment 1, a pneumatic injection equipment 2, a gas source equipment 3 and a purification ash combustion equipment 4; among them,

[0035] The outlet of the purified ash storage device 1 is connected to the inlet of the pneumatic injection device 2, and the outlet of the pneumatic injection device 2 and the outlet of the gas source device 3 are both connected to the inlet of the purified ash combustion device 4, so that the purified ash and the gas injected by the gas source device 3 can be mixed in the purified ash combustion device 4;

[0036] The purified ash combustion device 4 includes a feeding device 41, a burner 42 and a preheater 43; the outlet of the pneumatic injection device 2 and the outlet of the gas source device 3 are both connected to the feeding device 41, the outlet of the feeding device 41 is connected to the inlet of the burner 42, and the outlet of the burner 42 extends into the preheater 43 so that the purified ash can be burned in the preheater 43 to make cement.

[0037] Specifically, the purified ash after purification treatment is generally pneumatically transported to the purified ash storage device 1 for storage. The purified ash storage device 1 is connected to an external nitrogen source and is sealed by nitrogen fluidization to prevent the purified ash from coming into contact with air and spontaneous combustion. The nitrogen pipeline is at the conical section at the bottom of the purified ash storage device 1. There is a dust removal device for pressure reduction at the upper part of the purified ash storage device 1. Continuously introducing nitrogen into the purified ash storage device 1 can not only isolate oxygen but also maintain normal pressure; the gas source device 3 can use a Roots blower, and the injected gas is air. The purified ash is sprayed into the burner 42 through a large air volume, so that the purified ash can be completely burned; the preheater 43 uses the preheater at the tail of the cement rotary kiln used in the prior art for cement preparation.

[0038] The closed calcium carbide purified ash recycling system provided by the present invention includes a purified ash storage device 1, a pneumatic injection device 2, a gas source device 3 and a purified ash combustion device 4. The purified ash storage device 1 is used to store the purified ash to be recycled. The purified ash to be recycled is mixed with the gas injected by the pneumatic injection device 2 and the gas source device 3 from the purified ash storage device 1, enters the purified ash combustion device 4, and is fully burned in the preheater 43 through the burner 42 to make cement, realizing the secondary utilization of the purified ash, and avoiding the increase in treatment cost and secondary pollution caused by the production of slag during the combustion of the purified ash.

[0039] As a preferred or optional implementation manner, the feeding device 41 includes a discharge pipeline 411, a distributor 412 and at least two feeding pipelines 413; the outlet of the pneumatic injection device 2 and the outlet of the gas source device 3 are both connected to the discharge pipeline 411, the outlet of the discharge pipeline 411 is connected to the distributor 412, the distributor 412 includes at least two outlets connected to its inlet, and each outlet of the distributor 412 is respectively connected to a feeding pipeline 413; the number of burners 42 is at least two, and each outlet of the distributor 412 is connected to a burner 42.

[0040] Specifically, the feeding device 41 includes two feeding pipelines 413. The distributor 412 is a Y-shaped tee, which can evenly divide the input one-way flow into two-way outputs to each burner 42, improving the working efficiency of the equipment; the angle at which each burner 42 extends into the preheater 43 is 25°-30°, enabling better combustion.

[0041] As a preferred or alternative embodiment, the outlets of at least two burners 42 are evenly distributed along the circumference of the preheater 43. The outlet of each burner 42 is located in the same plane and the plane where it is located is perpendicular to the axis of the preheater 43, resulting in more sufficient combustion.

[0042] As a preferred or alternative embodiment, the lengths of each feeding pipeline 413 are equal. This ensures that the resistance in each feeding pipeline 413 is equal, so that the amount of purified ash entering each feeding pipeline 413 is equal.

[0043] As a preferred or alternative embodiment, the pneumatic injection device 2 includes a feeding pipeline 21, an injection tank 22 and a rotary feeder 23; the feeding pipeline 21 can connect the purified ash storage device 1 and the injection tank 22. A rotary feeder 23 is provided at the outlet of the injection tank 22, and the outlet of the rotary feeder 23 is connected to the feeding device 41;

[0044] A maintenance isolation valve 211, a pneumatic isolation valve 212 and an injection tank inlet valve 213 are serially arranged on the feeding pipeline 21.

[0045] Specifically, the pipelines in the pneumatic injection device 2 are all made of seamless steel pipes; the rotary feeder 23 is equipped with a variable-frequency motor, and the variable-frequency motor is adjusted through a frequency converter to adjust the rotation speed of the rotary feeder 23, thereby adjusting the injection amount of purified ash. For the specific structure, please refer to the Chinese utility model patent with the authorization announcement number CN203392503U, which will not be elaborated here. The outlet of the rotary feeder 23 is connected to the discharge pipeline 411, and a pressure transmitter is installed in the discharge pipeline 411 to detect the pressure in the discharge pipeline 411; a pressure transmitter is provided in the injection tank 22 to detect the pressure in the injection tank 22; the maintenance isolation valve 211 on the feeding pipeline 21 is used to manually close this valve for maintenance when the pneumatic injection device 2 fails. The pneumatic isolation valve 212 and the injection tank inlet valve 213 are used to control the on-off between the purified ash storage device 1 and the injection tank 22. A flexible connection is provided between the pneumatic isolation valve 212 and the injection tank inlet valve 213, which can make the weighing of the pneumatic injection device more accurate.

[0046] As a preferred or alternative embodiment, the pneumatic injection device 2 further includes a fluidization pressurization gas path 24. The inlet of the fluidization pressurization gas path 24 is connected to an external nitrogen source, and the outlet is connected to the injection tank 22.

[0047] Specifically, the fluidizing and pressurizing gas path 24 can supplement nitrogen into the injection tank 22. Firstly, it can prevent air from entering the injection tank 22 to avoid spontaneous combustion of the purified ash. Secondly, it can pressurize the injection tank 22 after the charging of the injection tank 22 is completed. Thirdly, it can fluidize the purified ash in the injection tank 22 to prevent the purified ash from sticking to the wall and caking in the injection tank 22. An air path valve is provided on the fluidizing and pressurizing gas path 24 to control the on-off of the fluidizing and pressurizing gas path 24.

[0048] As a preferred or alternative embodiment, the pneumatic injection device 2 further includes a weighing and metering device 25, and the weighing and metering device 25 is connected to the injection tank 22.

[0049] Specifically, the weighing and metering device 25 can be an electronic scale. One end of it is fixed to the ground or the frame, etc., and the other end is connected to the injection tank 22. It can weigh the weight of the injection tank 22, and according to the change value of the weight, feedback and adjust the rotation speed of the rotary feeder 23 to adjust the injection accuracy.

[0050] As a preferred or alternative embodiment, the pneumatic injection device 2 further includes an exhaust device 26 capable of discharging the gas in the injection tank 22. The exhaust device 26 includes an exhaust dust collector 261 and an exhaust valve 262 arranged in series, and the exhaust dust collector 261 is communicated with the injection tank 22.

[0051] Specifically, the exhaust dust collector 261 is a dust collector that can be purchased on the current market, and its specific structure will not be elaborated here. The exhaust device 26 is used to control the pressure in the injection tank 22. When the pressure in the injection tank 22 is greater than the set air pressure, the exhaust valve 262 is opened to discharge the gas. During the exhaust process, the exhaust dust collector 261 is used to filter the discharged gas to avoid environmental pollution.

[0052] As a preferred or alternative embodiment, the pneumatic injection device 2 further includes a balancing device 27. The balancing device 27 includes a balance pipe 271 and a balance pneumatic valve 272. Both ends of the balance pipe 271 are respectively communicated with the outlet of the rotary feeder 23 and the upper region of the injection tank 22, and the balance pneumatic valve 272 is arranged on the balance pipe 271.

[0053] Specifically, the balancing device 27 is used to keep the pressure at the outlet and inlet of the rotary feeder 23 equal during the normal injection process, so that the purified ash falls into the rotary feeder 23 by gravity instead of being blown out by pressure, avoiding the occurrence of material surge phenomenon that causes injection fluctuation and reducing the injection accuracy. The function of the balance pneumatic valve 272 is to prevent the air source device 3 from blowing air into the injection tank 22 when the injection tank 22 is being charged.

[0054] In addition, the closed calcium carbide purification ash recycling system provided by the present invention further includes a PLC control module, which is electrically connected to the pressure transmitters in the injection tank 22 and the discharge pipeline 411, the weighing and metering device 25, the pneumatic isolation valve 212, the injection tank inlet valve 213, the balance pneumatic valve 272, the exhaust valve 262, and the rotary feeder 23 respectively.

[0055] A method for using the closed calcium carbide purification ash recycling system provided by any technical solution of the present invention includes the following steps:

[0056] Step A: Before use, start the gas source device 3 to clean the injection pipeline and cool the burner 42. The rotary feeder 23 stops, the maintenance isolation valve 211 opens, and the pneumatic isolation valve 212, the injection tank inlet valve 213, the balance pneumatic valve 272, and the exhaust valve 262 close.

[0057] Step B: When starting to use, the operator sets the required injection volume, checks that the pressure in the injection pipeline is normal, opens the exhaust valve 262, closes the balance pneumatic valve 272, reduces the pressure in the injection tank 22 to the set value, and then sequentially opens the injection tank inlet valve 213 and the pneumatic isolation valve 212. The purification ash falls into the injection tank 22 from the purification ash storage device 1 by gravity. When feeding, the residual gas in the injection tank 22 is discharged into the atmosphere through the dust collector 261.

[0058] Step C: When the weighing and metering device 25 detects that the injection tank is full of materials, sequentially close the injection tank inlet valve 213, the pneumatic isolation valve 212, and the exhaust valve 262, open the fluidization and pressurization gas path 24, nitrogen enters the injection tank 22, and the pressure in the injection tank 22 starts to rise.

[0059] Step D: When the pressure in the injection tank 22 is not less than the pressure in the discharge pipeline 411, open the balance pneumatic valve 272, start the rotary feeder 23, the purification ash enters the burner 42 through the discharge pipeline 411 and is injected into the preheater 43 for combustion. Adjust the rotation speed of the rotary feeder 23 according to the set injection volume, send the purification ash into the discharge pipeline 411, and then evenly distribute it through the distributor 412 and enter the preheater 43 through the burner 42. The PLC control module continuously adjusts the rotation speed of the rotary feeder 23 through the change of the reading of the weighing and metering device 25, so that the actual injection volume of the system is infinitely close to the injection volume set by the operator, achieving the injection accuracy required by the system.

[0060] Step E: When the weighing and metering device 25 detects that the materials in the injection tank 22 are insufficient and the injection tank 22 needs to be refilled, at this time, the rotary feeder 23 continues to operate, but no longer adjusts the rotation speed according to the change value of the weighing and metering device 25, but operates at a suitable fixed rotation speed, and repeat operation steps B to D.

[0061] Step F: After use, turn off the rotary feeder 23, and turn off the gas source device 3 after purging the pipeline.

[0062] If it is a temporary shutdown, the gas source device 3 will keep running to cool the clean burner 42 to prevent the burner 42 from being damaged by high temperature. After the temporary stop, the operator can start the pneumatic injection device 2 again at any time according to needs.

[0063] For any of the technical solutions disclosed by the present invention as described above, unless otherwise stated, if it discloses a numerical range, the disclosed numerical range is a preferred numerical range. Any person skilled in the art should understand that the preferred numerical range is only the numerical values with obvious technical effects or representativeness among many implementable numerical values. Since there are too many numerical values to enumerate, the present invention only discloses some numerical values to illustrate the technical solutions of the present invention. Moreover, the above-listed numerical values should not constitute a limitation to the protection scope of the present invention.

[0064] If terms such as "first" and "second" are used in this article to limit components, those skilled in the art should know that the use of "first" and "second" is only for the convenience of distinguishing components in description. Unless otherwise stated, the above terms have no special meanings.

[0065] Meanwhile, for the present invention as described above, if it discloses or involves components or structural parts that are fixedly connected to each other, then, unless otherwise stated, the fixed connection can be understood as: a detachable fixed connection (such as using bolts or screws for connection), or it can also be understood as: a non-detachable fixed connection (such as riveting or welding). Of course, the components fixedly connected to each other can also be an integral structure (such as being replaced by being integrally formed by casting process (except where it is obviously impossible to adopt the integral forming process).

[0066] In addition, for any of the technical solutions disclosed by the present invention, the terms used to represent the positional relationship or shape, unless otherwise stated, include states or shapes that are approximate, similar, or close to it. Any component provided by the present invention can either be assembled from multiple separate components or be a single component manufactured by an integral forming process.

[0067] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that: it is still possible to modify the specific implementation manners of the present invention or make equivalent replacements for some technical features; without departing from the spirit of the technical solutions of the present invention, they should all be covered within the scope of the technical solutions claimed by the present invention.

Claims

1. A closed calcium carbide purification ash recycling system, characterized in that, It includes a purified ash storage device, a pneumatic injection device, a gas source device, and a purified ash combustion device; among them, the outlet of the purified ash storage device is communicated with the inlet of the pneumatic injection device, and the outlets of the pneumatic injection device and the gas source device are both communicated with the inlet of the purified ash combustion device so that the purified ash and the gas blown in by the gas source device can be mixed in the purified ash combustion device; the purified ash combustion device includes a feeding device, a burner, and a preheater; the outlets of the pneumatic injection device and the gas source device are both communicated with the feeding device, the outlet of the feeding device is communicated with the inlet of the burner, and the outlet of the burner extends into the preheater so that the purified ash can be burned in the preheater to make cement; the feeding device includes a discharge pipeline, a distributor, and two feeding pipelines, and the distributor is a Y-shaped tee; the outlets of the pneumatic injection device and the gas source device are both communicated with the discharge pipeline, the outlet of the discharge pipeline is communicated with the distributor, the distributor includes two outlets communicated with its inlet, and each outlet of the distributor is respectively communicated with a feeding pipeline; the number of burners is two, and each outlet of the distributor is communicated with one of the burners; the outlets of the two burners are evenly distributed along the circumference of the preheater, each burner outlet is located in the same plane and the plane where it is located is perpendicular to the axis of the preheater; the lengths of each of the feeding pipelines are equal; the angle at which each burner extends into the preheater is 25° to 30°; 2. The closed calcium carbide purification ash recycling system according to claim 1, wherein the pneumatic injection device includes a feeding pipeline, a blowing tank, and a rotary feeder; the feeding pipeline can communicate the purified ash storage device and the blowing tank, the rotary feeder is arranged at the outlet of the blowing tank, and the outlet of the rotary feeder is communicated with the feeding device; a maintenance isolation valve, a pneumatic isolation valve, and a blowing tank inlet valve are serially arranged on the feeding pipeline; 3. The closed calcium carbide purification ash recycling system according to claim 2, characterized in that, the pneumatic injection device further includes a fluidization pressurization gas path, the inlet of the fluidization pressurization gas path is communicated with an external nitrogen source, and the outlet is communicated with the blowing tank; 4. The closed calcium carbide purification ash recycling system according to claim 2, characterized in that, the pneumatic injection device further includes a weighing and metering device, and the weighing and metering device is connected to the blowing tank; 5. The closed calcium carbide purification ash recycling system according to claim 2, wherein the pneumatic injection device further includes an exhaust device capable of discharging the gas in the blowing tank, and the exhaust device includes an exhaust dust collector and an exhaust valve arranged in series, and the exhaust dust collector is communicated with the blowing tank; 6. The closed calcium carbide purification ash recycling system according to claim 2, wherein the pneumatic injection device further includes a balancing device, and the balancing device includes a balance pipe and a balance pneumatic valve, the two ends of the balance pipe are respectively communicated with the outlet of the rotary feeder and the upper region of the blowing tank, and the balance pneumatic valve is arranged on the balance pipe; 7. A method for using a closed calcium carbide purification ash recycling system according to any one of claims 1-6, characterized in that, It includes the following steps: Step A: Before use, start the gas source device, the rotary feeder stops, the maintenance isolation valve is opened, and the pneumatic isolation valve, the blowing tank inlet valve, the balance pneumatic valve, and the exhaust valve are closed; Step B: When starting to use, open the exhaust valve, close the balance pneumatic valve, after reducing the pressure in the blowing tank, sequentially open the blowing tank inlet valve and the pneumatic isolation valve; Step C: After the weighing and metering device detects that the injection tank is full of materials, sequentially close the inlet valve, pneumatic isolation valve and exhaust valve of the injection tank, and open the fluidization and pressurization gas circuit; Step D: When the pressure in the injection tank is not less than the pressure in the discharge pipeline, open the balance pneumatic valve and start the rotary feeder; Step E: When the weighing and metering device detects that the materials in the injection tank are insufficient, the rotary feeder continues to operate, and repeat operating steps B to D; Step F: After use, close the rotary feeder, and the gas source device is closed after purging the pipeline.

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