Ash cleaning and conveying system for blast furnace gas bag-type dust collector and working method

Abstract

The invention discloses an ash cleaning and conveying system for a blast furnace gas bag-type dust collector and a working method. The system comprises an ash bin and at least one bag box body, a clean gas outlet, a raw gas inlet, a raw gas outlet and an ash discharge port are formed in the cloth bag box body; the clean gas outlet is connected with a high-pressure clean gas main pipe, the raw gas inlet is connected with a raw gas main pipe, the raw gas outlet is connected with an ash conveying pipeline through a first pipeline, and the ash discharging port is connected with an ash bin through the ash conveying pipeline; the clean gas outlet is connected with the first pipeline through a second pipeline, and a pressure regulating valve is arranged on an ash conveying gas recovery pipeline of the ash bin; compared with an existing process, the total investment is smaller and more economical while the aim that a process dust removal system does not use nitrogen for ash removal is achieved, meanwhile, scouring of dust to an ash conveying system can be reduced, and the service life of the ash conveying system is prolonged; therefore, the method is suitable for new construction, modification and extension projects of a blast furnace gas purification and recovery system.

Description

Technical Field

[0001] The invention belongs to the technical field of blast furnace gas dust removal, and in particular relates to a dust cleaning and conveying system for a blast furnace gas bag filter and a working method thereof. Background Art

[0002] The statements herein merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] As a mature dust removal process, dry dust removal of blast furnace gas has been widely used in blast furnaces. The basic principle of dry dust removal is: the blast furnace raw gas from the gravity dust collector enters the bag filter box through the dry dust removal raw gas pipeline and branch pipe; the dusty gas enters the box from the bottom of the dust collector, passes through the diversion system, and the airflow is redistributed. The larger dust particles naturally settle to the ash collecting hopper at the bottom of the box, and the smaller dust particles rise with the gas and are filtered on the outer surface through the bag (the bag filter method is external filtration, with keel support inside). The filtered clean gas passes through the box outlet valve and branch pipe, and is collected in the clean gas pipeline and sent to the blast furnace gas residual pressure turbine power generation device (TRT) or blast furnace pressure regulating valve group.

[0004] As the dust on the outer surface of the bag of the box dust collector continues to increase, the gas filtration resistance increases accordingly. When it reaches a certain value (or accumulates for a certain period of time), cleaning is required. The existing cleaning methods usually use nitrogen pulse backblowing cleaning and high-pressure clean gas backblowing cleaning. Among them, nitrogen pulse back-blowing cleaning consumes a lot of nitrogen and is expensive; and nitrogen pulse back-blowing cleaning must use a pulse valve, especially the pulse diaphragm, which is a vulnerable part and needs to be checked and repaired and replaced frequently, which not only increases the labor intensity of workers, but also increases the maintenance and repair costs; high-pressure clean coal gas back-blowing cleaning can solve the above problems caused by nitrogen pulse back-blowing cleaning, but high-pressure clean coal gas back-blowing cleaning has the following problems: before back-blowing cleaning, the pressure relief time in the dust collector box is long, affecting the normal operation of the dust collector; the pressure relief process has a great impact on the gas pipeline, affecting the stable operation of the entire blast furnace gas system; the pressure relief process is uncontrollable from the highest (high-pressure clean coal gas main pressure) to the lowest (low-pressure clean coal gas main pressure), which is easy to cause fatigue damage to system equipment and pipelines; the raw coal gas of the raw coal gas release cleaning is discharged into the environment through the release valve, causing environmental pollution problems; in addition, the ash generated in the cleaning process is transported by uncontrollable dilute phase pneumatic conveying, resulting in high-speed scouring of the ash unloading valve group by particles in the dust, which in turn causes serious wear of the ash conveying system. Summary of the invention

[0005] The purpose of the present invention is to provide an ash cleaning and conveying system and a working method for a blast furnace gas bag filter, in which bag backblowing is performed while ash conveying, and the ash conveying and backblowing cleaning processes are flexible and controllable.

[0006] To achieve the above object, the present invention is realized by the following technical solutions:

[0007] In a first aspect, an embodiment of the present invention provides a dust cleaning and conveying system for a blast furnace gas bag filter, including a dust bin and at least one bag box body; a clean gas outlet, a raw gas inlet, a raw gas outlet and a dust discharge port are arranged on the bag box body; the clean gas outlet is connected to a high-pressure clean gas main pipe, the raw gas inlet is connected to a raw gas main pipe, the raw gas outlet is connected to a conveying ash pipe through a first pipe, and the dust discharge port is connected to the dust bin through the conveying ash pipe; the clean gas outlet is connected to the first pipe through a second pipe, and a pressure regulating valve is arranged on the conveying ash gas recovery pipe of the dust bin.

[0008] As a further technical solution, an outlet butterfly valve is arranged on the pipe connecting the clean gas outlet to the high-pressure clean gas main pipe, and an inlet butterfly valve is arranged on the pipeline connecting the raw gas inlet to the raw gas main pipe.

[0009] As a further technical solution, a raw gas ash conveying valve is arranged at the raw gas outlet, the raw gas outlet is connected to the second pipe through a pipeline, the second pipe is connected to the first pipe, and the first pipe is connected to the conveying ash pipe.

[0010] As a further technical solution, a clean gas ash conveying valve is arranged at a position of the second pipe close to the clean gas outlet.

[0011] As a further technical solution, a discharging valve group is arranged at the dust discharge port.

[0012] As a further technical solution, a plurality of bag box bodies are provided, and the plurality of bag box bodies are arranged in parallel. The clean gas outlet of each bag box body is connected to the high-pressure clean gas main pipe, the raw gas inlet of each bag box body is connected to the raw gas main pipe, and the dust discharge port of each bag box body is connected to the conveying ash pipe.

[0013] As a further technical solution, the conveying ash pipe is also connected to a low-pressure nitrogen gas supply pipeline.

[0014] As a further technical solution, a dust removal filter bag is arranged in the dust bin, and the conveying ash gas recovery pipe of the dust bin is connected to a low-pressure clean gas main pipe.

[0015] In a second aspect, an embodiment of the present invention provides a working method for a dust cleaning and conveying system for a blast furnace gas bag filter, including the following steps:

[0016] In the dust removal state, the raw coal gas in the main raw coal gas pipe enters the bag box body through the raw coal gas inlet for dust removal. The purified coal gas after dust removal enters the high-pressure purified coal gas main pipe through the purified coal gas outlet. The dust removal ash generated by the bag box body adheres to the surface of the bag or falls off and is temporarily stored in the ash hopper under the bag box body;

[0017] In the ash cleaning state, the purified coal gas in the high-pressure purified coal gas main pipe enters the bag box body for reverse blowing ash cleaning. The cleaned dust enters the ash conveying pipe through the ash discharge port. At the same time, the generated raw coal gas passes through the raw coal gas outlet and the first pipe and enters the ash conveying pipe. Under the action of the raw coal gas, the dust removal ash is conveyed to the ash bin;

[0018] After the ash cleaning is completed, the purified coal gas in the high-pressure purified coal gas main pipe enters the ash conveying pipe through the second pipe and the first pipe to clean the ash conveying pipe.

[0019] As a further technical solution, during the ash cleaning process, the pressure in the ash bin is adjusted between 0.008 MPa and 0.3 MPa by controlling the pressure regulating valve on the ash conveying gas recovery pipe of the ash bin, so as to control the reverse blowing intensity of the bag box body, the ash discharge amount at the ash discharge port and the raw coal gas amount for ash conveying.

[0020] The beneficial effects of the above embodiments of the present invention are as follows:

[0021] The various valves set in the system of the present invention and the additional pipes can realize the switching of different working states of dust removal, ash cleaning and ash conveying, and the purging of the ash conveying pipe. During the ash cleaning and ash conveying process, the raw coal gas is used as the power gas source for ash conveying, which completely solves the environmental pollution problem caused by the original raw coal gas discharging and ash cleaning, and at the same time does not require a nitrogen pulse reverse blowing system, reduces the usage amount of nitrogen, and reduces the system operation cost; when cleaning the bag, the reverse flow coal gas is directly used for ash conveying, and the bag box body can store less or even no ash, thereby reducing the operating weight of the equipment, and thus reducing the loads such as equipment support platforms to save investment.

[0022] The ash bin set in the present invention can, firstly, play a role in pressure relief, realize the rapid and stable pressure relief of the bag filter, ensure that the bag filter can perform stable and controllable pressure relief and use the pressure relief gas for ash conveying, laying a foundation for the subsequent effective reverse blowing and ash cleaning of the bag filter. Secondly, it can store the dust cleaned out of the bag filter through reverse blowing and remove dust from the ash conveying gas, realizing the full recovery and utilization of the coal gas; thirdly, a pressure regulating valve is set on the ash bin, which can control the ash conveying flow rate and flow velocity during the ash cleaning process by controlling the pressure of the ash bin, so as to control the reverse blowing intensity of the bag box body.

[0023] By controlling the pressure regulating valve on the ash silo, the present invention adjusts the pressure in the ash silo between 0.008 MPa and 0.3 MPa, and an ideal solid-gas ratio and flow velocity for dilute-phase conveying of dust removal ash can be obtained. At the same time, it is no longer required that there must be some dust removal ash remaining in the bag dust discharge hopper to avoid the erosion problem caused by the high-speed passage of the dust removal ash in the box through the discharge valve group under high pressure difference. Because the conveying pressure and flow velocity are controllable, the problem of serious wear of the dilute-phase conveying process system in the current dust removal ash conveying system of blast furnace gas bag filters can be well solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings forming a part of this specification are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation of the present invention.

[0025] Figure 1 It is a schematic diagram of the ash cleaning and conveying system for a blast furnace gas bag filter of the present invention.

[0026] The schematic diagram is only for illustration;

[0027] Among them, 1. Bag box; 101. Raw gas inlet; 102. Clean gas outlet; 103. Ash discharge port; 104. Raw gas outlet; 2. Ash silo; 3. Ash conveying pipeline; 4. Pressure regulating valve; 5. Inlet butterfly valve; 6. Outlet butterfly valve; 7. Raw gas ash conveying valve; 8. Clean gas ash conveying valve; 9. Discharge valve group. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] It should be noted that the following detailed descriptions are all exemplary and are intended to provide further explanations of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0029] Embodiment 1

[0030] In a typical embodiment of the present invention, as Figure 1 shown, a ash cleaning and conveying system for a blast furnace gas bag filter is provided, including an ash silo 2 and at least one bag box 1; a clean gas outlet 102, a raw gas inlet 101, a raw gas outlet 104 and an ash discharge port 103 are provided on the bag box 2; the clean gas outlet 102 is connected to the high-pressure clean gas main pipe, the raw gas inlet is connected to the raw gas main pipe, the raw gas outlet 104 is connected to the ash conveying pipeline through a first pipeline, and the ash discharge port 103 is connected to the ash silo 2 through the ash conveying pipeline 3; the clean gas outlet is connected to the first pipeline through a second pipeline, and a pressure regulating valve 4 is provided on the ash conveying gas recovery pipeline of the ash silo.

[0031] Specifically, the clean gas outlet is arranged at the top of the bag filter housing, the ash discharge port is arranged at the bottom of the bag filter housing, the raw gas inlet and the raw gas outlet are arranged at the bottom side of the bag filter housing, and the raw gas ash conveying valve is arranged in the lower housing part below the ceiling of the dust removal housing. During normal operation, the raw gas outlet is in a closed state. The raw gas to be dust-removed enters the bag filter housing through the raw gas inlet for dust removal. The clean gas generated after dust removal is discharged through the clean gas outlet. The dust removed adheres to the filter bag or deposits and is temporarily stored in the lower hopper of the housing. When in the dust cleaning state, the raw gas inlet is in a closed state. High-pressure clean gas enters the bag filter housing through the clean gas outlet to clean the filter bags. The removed dust is discharged through the ash discharge port. The raw gas generated during dust cleaning serves as the ash conveying gas, so that neither nitrogen is required for the dust cleaning nor for the ash conveying process, reducing the nitrogen consumption. In addition, the bag filter housing is connected to the ash silo through an ash conveying pipe. By controlling the internal pressure of the ash silo, the gas flow rate and flow in the ash conveying pipe can be adjusted, thereby controlling the backwashing intensity of the bag filter housing. When necessary, the backwashing intensity can also be enhanced by closing the clean gas outlet valve and then opening the clean gas outlet valve after the pressure in the housing drops to the control value of the regulating valve.

[0032] In this embodiment, an outlet butterfly valve 6 is arranged on the pipeline connecting the clean gas outlet and the high-pressure clean gas main pipe, and an inlet butterfly valve 5 is arranged on the pipeline connecting the raw gas inlet and the raw gas main pipe. By arranging the outlet butterfly valve and the inlet butterfly valve, the opening and closing of the clean gas outlet and the raw gas inlet can be controlled, thereby changing the working state of the system.

[0033] In this embodiment, a raw gas ash conveying valve 7 is arranged at the raw gas outlet. The raw gas outlet is connected to the second pipeline through a pipeline. The second pipeline is connected to the first pipeline, and the first pipeline is connected to the ash conveying pipe. A clean gas ash conveying valve is arranged at a position of the second pipeline close to the clean gas outlet. By arranging the raw gas ash conveying valve 7 and the clean gas ash conveying valve, the switching between the dust cleaning process and the ash conveying pipe dust cleaning process can be realized. That is, when the raw gas ash conveying valve is in an open state and the clean gas ash conveying valve is in a closed state, the raw gas generated during the dust cleaning process of the dust removal housing is used for ash conveying. When the raw gas ash conveying valve is in a closed state and the clean gas ash conveying valve is in an open state, high-pressure clean gas is used for ash conveying or cleaning of the ash conveying pipe.

[0034] In this embodiment, a discharge valve group 9 is arranged at the ash discharge port. By opening and closing the discharge valve group, the controllable discharge of the dust in the ash hopper is realized, so that the ash conveying system works in the best working condition.

[0035] In this embodiment, a plurality of cloth bag boxes are provided. The plurality of cloth bag boxes are connected in parallel. The net gas outlet of each cloth bag box is connected to the high-pressure net gas main pipe, the raw gas inlet of each cloth bag box is connected to the raw gas main pipe, the ash discharge port of each cloth bag box is connected to the ash conveying pipe, and a corresponding second pipe is configured for each cloth bag box. The second pipes of the plurality of cloth bag boxes are connected in parallel and are all connected to the first pipe. The second pipe serves to convey the ash conveying gas.

[0036] In this embodiment, the ash conveying pipe is also connected to the low-pressure nitrogen gas supply pipeline. In the case of condensation or blockage during the ash conveying process, nitrogen is used for cleaning.

[0037] In this embodiment, a dust removal filter bag is provided in the ash bin. The ash conveying gas recovery pipe of the ash bin is connected to the low-pressure net gas main pipe. After the raw gas for ash conveying enters the ash bin for dust removal, it enters the low-pressure net gas main pipe through the ash conveying gas recovery pipe for recovery. The design pressure of the ash bin should be the same as or close to that of the cloth bag dust removal box body.

[0038] The working principle of the entire system is as follows: In the dust removal state, the raw gas in the raw gas main pipe enters the cloth bag box through the raw gas inlet for dust removal. The dust-removed net gas enters the high-pressure net gas main pipe through the net gas outlet. The dust removal ash generated by the cloth bag box adheres to the surface of the cloth bag or falls off and is temporarily stored in the lower ash hopper of the cloth bag box. In the ash cleaning state, the net gas in the high-pressure net gas main pipe enters the cloth bag box for reverse blowing ash cleaning. The cleaned dust enters the ash conveying pipe through the ash discharge port. At the same time, the generated raw gas passes through the raw gas outlet and the first pipe and enters the ash conveying pipe, and under the action of the raw gas, the dust removal ash is conveyed to the ash bin. After the ash cleaning is completed, the net gas in the high-pressure net gas main pipe enters the ash conveying pipe through the second pipe and the first pipe to clean the ash conveying pipe.

[0039] Further, during the ash cleaning process, the pressure in the ash bin is adjusted between 0.008 MPa and 0.3 MPa by controlling the pressure regulating valve on the ash conveying gas recovery pipe of the ash bin to control the reverse blowing intensity of the cloth bag box, the ash discharge amount at the ash discharge port, and the raw gas amount for ash conveying.

[0040] The specific working process is as follows:

[0041] During the normal production process, the inlet butterfly valve, the outlet butterfly valve, and the ash discharge valve group are in the open state. The raw gas at 0.2 - 0.3 MPa from the blast furnace rough dust removal system passes through the cloth bags in the dust removal box body, and the dust content is reduced to less than 5 mg / m 3 .

[0042] After a certain period of time or when the box resistance reaches a certain value, it is determined that a certain thickness of dust has adhered to the surface of the cloth bag, and dust cleaning should be carried out, and the box body reverse blowing program should be started. Start the ash discharge valve group. The clean gas enters the cloth bag box body from the high-pressure clean gas main pipe through the butterfly valve at the outlet of the cloth bag box body. When the reverse-flow gas in the cloth bag box body passes through the dust removal cloth bag, the external filter cloth bag deforms from concave to convex, so that the dust on the outer surface of the filter bag shakes off, realizing dust cleaning; the raw gas generated by dust cleaning enters the ash conveying pipeline through the raw gas ash conveying valve; at this time, the dust removed from the surface of the cloth bag is collected by the ash hopper at the lower part of the dust collector box body, and enters the ash conveying pipeline through the control of the ash discharge valve group for the ash discharge amount. The raw gas is conveyed for ash, and the dust-containing gas is recycled as clean gas after being dust-removed by the ash bin; by controlling the ash discharge amount and the ash conveying gas amount (controlling the ash conveying gas recovery pressure regulating valve to adjust the ash bin pressure between 0.008 MPa and 0.3 MPa), an ideal solid-gas ratio and flow velocity for the dilute-phase conveying of dust removal ash can be obtained; at the same time, it is no longer required to have dust remaining in the remaining part of the cloth bag ash discharge hopper to avoid the erosion problem caused by the high-speed passing of the dust in the box body through the ash discharge valve group under high pressure difference. Because the conveying pressure and flow velocity are controllable, the serious wear problem of the ash conveying system in the current blast furnace gas cloth bag dust removal ash conveying system using the dilute-phase conveying process system can be well solved, and the service life of the ash conveying system can be extended.

[0043] Through the above operations, using the reverse-blowing raw gas as the power gas source for ash conveying, ash is conveyed while dust is cleaned. The cloth bag box body can be free of ash, thereby reducing the operating weight of the equipment. Or after multiple dust cleanings, ash can be centrally conveyed, and the cloth bag box body can be used as a dust storage container, making the operation more flexible and convenient. After the dust cleaning of the cloth bag box body is completed, close the ash discharge valve group, close the raw gas ash conveying valve, open the clean gas ash conveying valve to clean the ash conveying pipeline, open the raw gas inlet valve of the box body to put the box body into production, and close the clean gas ash conveying valve to wait for the next reverse-blowing process.

[0044] During the whole working process, the raw gas is used as the power gas source for ash conveying, completely solving the environmental pollution problem caused by the original raw gas discharging and dust cleaning, and at the same time, there is no need for a nitrogen pulse reverse-blowing system; at the same time, through the adjustment of the ash conveying gas recovery pressure regulating valve, the dilute-phase ash conveying pressure and flow rate can be controlled, effectively reducing the erosion of the ash conveying system by the dust driven by the ash conveying gas, and extending the service life of the ash conveying system.

[0045] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, various changes and modifications can be made to the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A dust removal system for blast furnace gas bag filter, characterized in that: It includes an ash bin and at least one bag box; the bag box is provided with a clean gas outlet, a raw gas inlet, a raw gas outlet and an ash discharge port; the clean gas outlet is connected to a high-pressure clean gas main pipe, the raw gas inlet is connected to a raw gas main pipe, the raw gas outlet is connected to an ash conveying pipe through a first pipe, and the ash discharge port is connected to an ash bin through an ash conveying pipe; the clean gas outlet is connected to a first pipe through a second pipe, and a pressure regulating valve is provided on the ash conveying gas recovery pipe of the ash bin.

2. The dust removal and conveying system for blast furnace gas bag filter according to claim 1, characterized in that: An outlet butterfly valve is arranged on the pipeline connecting the clean gas outlet with the high-pressure clean gas main pipe, and an inlet butterfly valve is arranged on the pipeline connecting the raw gas inlet with the raw gas main pipe.

3. The dust removal and conveying system for blast furnace gas bag filter according to claim 1, characterized in that: A raw gas ash conveying valve is provided at the raw gas outlet, and the raw gas outlet is connected to the second pipeline through a pipeline, the second pipeline is connected to the first pipeline, and the first pipeline is connected to the ash conveying pipeline.

4. The dust removal and conveying system for blast furnace gas bag filter according to claim 1, characterized in that: A clean gas ash conveying valve is arranged near the clean gas outlet of the second pipeline.

5. The dust removal and conveying system for blast furnace gas bag filter according to claim 1, characterized in that: An ash discharge valve group is arranged at the ash discharge port.

6. The dust removal and conveying system for blast furnace gas bag filter according to claim 1, characterized in that: There are multiple bag boxes, which are arranged in parallel. The clean gas outlet of each bag box is connected to the high-pressure clean gas main, the raw gas inlet of each bag box is connected to the raw gas main, and the ash discharge port of each bag box is connected to the ash conveying pipeline.

7. The dust removal and conveying system for blast furnace gas bag filter according to claim 1, characterized in that: The ash conveying pipeline is also connected to a low-pressure nitrogen gas supply pipeline.

8. The dust removal and conveying system for blast furnace gas bag filter according to claim 1, characterized in that: A dust removal filter bag is arranged in the ash bin, and the ash conveying gas recovery pipeline of the ash bin is connected to the low-pressure clean coal gas main.

9. A working method for a dust cleaning and conveying system for a blast furnace gas bag filter according to any one of claims 1 to 8, characterized in that: The following steps are involved: In the dust removal state, the raw gas in the raw gas main enters the bag box through the raw gas inlet for dust removal, and the clean gas after dust removal enters the high-pressure clean gas main pipeline through the clean gas outlet. The dust generated by the bag box adheres to the surface of the bag, or falls off and is temporarily stored in the ash hopper under the bag box; In the ash cleaning state, the clean coal gas in the high-pressure clean coal gas main pipeline enters the bag box for back-blowing cleaning. The cleaned dust enters the ash conveying pipeline through the ash discharge port. At the same time, the generated raw coal gas enters the ash conveying pipeline through the raw coal gas outlet and the first pipeline. The dust removal ash is transported to the ash bin under the action of the raw coal gas. After the ash cleaning is completed, the clean coal gas in the high-pressure clean coal gas main pipeline enters the ash conveying pipeline through the second pipeline and the first pipeline to clean the ash conveying pipeline.

10. The working method of the dust cleaning and conveying system for blast furnace gas bag filter according to claim 9, characterized in that: During the ash cleaning process, the ash bin pressure is adjusted between 0.008MPa-0.3MPa by controlling the pressure regulating valve on the ash gas recovery pipeline of the ash bin to control the backflushing intensity of the bag box, the ash discharge amount at the ash discharge port and the ash delivery waste gas volume.

Images