Intelligent waste heat boiler ash removal device and method

Abstract

The invention provides an intelligent waste heat boiler ash removal device and method, the ash removal device is used for a waste heat boiler, and the ash removal device comprises a spraying device, a plurality of sets of blowing gas header pipes, a transmission device, a blowing gas grading valve and a blowing gas hose; a transmission device is arranged on the outer side of the shell and at one end of the extending direction of the spraying device; each group of blowing header pipes corresponds to one transmission device; the blowing gas grading valve corresponding to each group of blowing gas header pipes is connected with the blowing gas header pipes through blowing gas hoses; and different groups of blowing header pipes are arranged up and down on the same vertical plane. The method comprises the steps that waste heat boiler smoke temperature drop and resistance drop are monitored; when the flue gas temperature drop and the resistance drop are within a set normal threshold range, ash removal work is periodically carried out according to a fixed frequency, and meanwhile, whether the ash deposition condition exists in a heat exchange tube bundle or not is judged; once dust is accumulated, dust removal is started. The dust removal device can remove stubborn accumulated dust on the surfaces of the heat exchange tubes to the maximum extent, and has a good dust removal effect.

Description

Technical Field

[0001] This application relates to the technical field of dust accumulation treatment, and particularly relates to an intelligent soot cleaning device and method for a waste heat boiler. Background Art

[0002] The flue gas at the converter outlet is characterized by high temperature (up to 1600 °C) and high dust content (80 - 150 g / Nm³). The main components of the dust are iron oxides (FeO, Fe2O3), iron powder, and CaO, SiO2, MnO, MgO, etc. Currently, the main methods for recovering converter gas are the wet gas recovery technology (OG method) and the dry gas recovery technology (LT method). The common disadvantage of these two methods is that they do not recover the waste heat in the medium and low temperature sections (below ~900 °C) of the converter flue gas. Therefore, using a waste heat boiler to recover the waste heat in the medium and low temperature sections of the converter flue gas and increase the steam production per ton of steel in the converter is an important measure to improve the energy efficiency of converter steelmaking.

[0003] However, on the heat transfer surface of the waste heat boiler, the dust in the converter outlet flue gas is likely to form an ash layer with extremely strong adhesion, especially in the convection tube bundle area of the waste heat boiler. The ash layer forms a heat insulation barrier on the heating surface, resulting in a decrease in heat exchange efficiency, a significant reduction in the steam output per ton of steel, and in severe cases, the ash may even cause blockage of the heat transfer surface in the flue gas system, thus causing the converter system and the waste heat boiler system to malfunction; the ash accumulation in the waste heat boiler also leads to poor cooling effect of the converter flue gas, resulting in too high temperature, affecting dust removal and the recovery of converter gas.

[0004] Currently, whether it is the OG method or the LT method for recovering converter gas, their common disadvantage is that they do not recover the waste heat in the medium and low temperature sections (below ~900 °C) of the converter flue gas, and there is no effective measure for the ash layer.

[0005] For heat exchange equipment with dusty flue gas in other devices, the existing soot cleaning methods are as follows: Shut-down soot cleaning: It is necessary to shut down the machine and manually enter a confined space for operation, which is time-consuming and has a high safety risk, and is not conducive to the continuous production of the device. Mechanical vibration soot cleaning: A vibration device is added in front of the convection tube bundle in the area where ash is likely to accumulate; however, the disadvantage is that the impact force of the vibration hammer decays significantly with distance, and it is difficult to remove the ash on the tube bundle far from the hammer head, there are soot cleaning dead corners, and the soot cleaning effect on nano-scale, strongly cemented, and sticky dust is poor; in addition, the equipment vibration is likely to generate electric sparks and is not suitable for working environments with flammable and explosive gases. Gas pulse purging: The shock wave decays quickly, and it can remove local ash accumulation to a certain extent. It is difficult to effectively peel off the dead corners inside the dense tube bundle, or highly viscous ash, agglomerated ash, or slag layer. Acoustic resonance soot cleaning: The sound energy intensity generated by a conventional acoustic soot cleaner is usually between 140 - 155 decibels, and the effect on sticky, severely fouled, or agglomerated ash is poor; the action distance is limited, and the noise is large during operation.

[0006] Therefore, current soot cleaning methods all have their respective drawbacks. In particular, it is difficult to effectively remove the soot in dead corners or with severe fouling, making it difficult to be directly applied to the heat exchange surface of waste heat boilers. Summary of the Invention

[0007] This application provides an intelligent waste heat boiler soot cleaning device and method, which can be used to solve the technical problem of difficult effective removal of soot in dead corners or with severe fouling.

[0008] This application provides an intelligent waste heat boiler soot cleaning device. The soot cleaning device is used for a waste heat boiler, which includes multiple groups of heat exchange tubes and a housing. Among them, a single group of heat exchange tubes extends horizontally, and different groups of heat exchange tubes are arranged at intervals in the vertical direction; the outer layer of the waste heat boiler is the housing;

[0009] The soot cleaning device includes a spraying and brushing device, a spraying and blowing air conveying system, and a transmission device;

[0010] Among them, the spraying and brushing device includes a nozzle and a brushing device. The spraying and brushing device is arranged on the spraying and blowing air pipeline. The spraying and blowing air is ejected from the nozzle along the spraying and blowing air pipeline in the spraying and blowing air conveying system. One end of the spraying and blowing air pipeline extending along the axis of the heat exchange tube is provided with a transmission device, and the transmission device is used to drive the spraying and brushing device to reciprocate along the axis extension direction of the heat exchange tube;

[0011] Among them, each group of heat exchange tubes corresponds to its own transmission device, that is, different groups of heat exchange tubes can be grouped for soot cleaning respectively.

[0012] The soot cleaning device further includes a monitoring and control module, and the monitoring and control module includes a controller, a temperature sensor and a pressure sensor. The controller controls the spraying and brushing device, the spraying and blowing air conveying system and the transmission device according to the values of the temperature sensor and the pressure sensor.

[0013] Further, the angle α between the nozzle and the cross-section of the spraying and blowing air pipeline where the nozzle is located ranges from 15° to 45°; the angle β between the nozzle and the longitudinal axis of the cross-section where the nozzle is located ranges from 60° to 120°.

[0014] Further, the spraying and blowing air pipeline includes a main spraying and blowing air pipe and a branch spraying and blowing air pipe;

[0015] The axis of the main spraying and blowing air pipe is parallel to the axis of the heat exchange tube. One or more branch spraying and blowing air pipes are vertically connected to the main spraying and blowing air pipe, and the plane formed by the branch spraying and blowing air pipe and the main spraying and blowing air pipe is parallel to the axis of the heat exchange tube. Among them, the spraying and brushing device is arranged at the branch spraying and blowing air pipe, and the brushing device is arranged corresponding to the heat exchange tube;

[0016] One end of the spraying and blowing air pipeline extending along the axis of the heat exchange tube is provided with a transmission device.

[0017] Further, the brushing device is arranged at the blowing gas pipeline through a collar.

[0018] The specific position of the brushing device is set according to the ash accumulation situation. In a feasible way, multiple brushing devices are arranged up and down at different positions of the blowing gas branch pipes; multiple brushing devices are arranged on one blowing gas branch pipe.

[0019] In the occasion of flammable and explosive flue gas, the brushing device is a ceramic brush, and the ceramic material has the advantage of insulation.

[0020] Further, the spraying and brushing device includes two types: type I blowing and brushing device and type II blowing and brushing device; among them, the type I blowing and brushing device is used to blow and brush a single-layer heat exchange tube, that is, each blowing gas main pipe corresponds to one heat exchange tube; the type II blowing and brushing device is used to blow and brush double-layer heat exchange tubes at the same time, that is, only one blowing gas main pipe is arranged between two heat exchange tubes.

[0021] Further, the blowing gas delivery system further includes a blowing gas grading valve, a blowing gas hose, and a blowing gas header pipe;

[0022] Among them, the blowing gas header pipe is connected to multiple blowing gas main pipes;

[0023] The blowing gas grading valve and the blowing gas header pipe are connected by a blowing gas hose.

[0024] Further, a seal is arranged between the blowing gas pipeline passing through the waste heat boiler shell and the shell, and the seal includes a telescopic seal and a fixed seal; among them, the fixed seal is connected to the shell and the blowing gas pipeline; the telescopic seal is connected to the fixed seal and the blowing gas pipeline, and the telescopic seal can expand and contract along with the movement of the transmission device and the blowing gas pipeline.

[0025] Further, an inlet gas temperature measuring point is arranged at the inlet of the heat exchange tube, and an outlet flue gas temperature measuring point is arranged at the outlet; a pressure inlet measuring point is arranged at the inlet of the heat exchange tube, and a pressure outlet measuring point is arranged at the outlet of the heat exchange tube.

[0026] Further, the blowing gas includes the flue gas after dust removal.

[0027] This application also provides a smart waste heat boiler ash cleaning method, which is realized by the device provided in this application; the method includes:

[0028] Specifically for the monitoring and control module, each inlet gas temperature measuring point, outlet flue gas temperature measuring point, pressure inlet measuring point, and pressure outlet measuring point are monitored in real time to monitor the temperature drop and resistance drop of the waste heat boiler flue gas;

[0029] When the temperature drop and resistance drop of the flue gas are within the set normal threshold range, the ash cleaning work is carried out periodically at a fixed frequency, and at the same time, it is judged whether there is ash accumulation in the heat exchange tube bundle;

[0030] Once ash accumulation occurs, the ash cleaning is started until the flue gas temperature drop and the resistance drop recover within the normal thresholds.

[0031] Furthermore, if any one of the flue gas temperature drop and the resistance drop of a certain stage of heat exchange tubes exceeds 15% of the normal threshold, it is considered that ash accumulation exists.

[0032] If it is judged that ash accumulation exists, control the opening of the jet air classification valve and the drive device to carry out ash cleaning: the corresponding jet air classification valve opens, the jet air enters the jet brushing device and is ejected outward through the nozzle; the drive device drives the jet air main pipe to move horizontally, thereby driving the brush sweeping device to move horizontally.

[0033] Furthermore, during periodic soot blowing or during the overall ash cleaning process, group ash cleaning is carried out. The group ash cleaning process includes:

[0034] The jet air classification valve of the first stage of the topmost layer is opened first, and the brush sweeping device is moved horizontally under the drive of the drive device. After reaching the set number of reciprocations, the jet air classification valve of the second stage is opened and jet brushed; and so on until all heat exchangers are cleaned.

[0035] Furthermore, when the ash accumulation is serious, a bottom-up group ash cleaning method is adopted. First, the jet air classification valve of the bottommost layer is opened, and the brush sweeping device is moved horizontally under the drive of the drive device. After reaching the set number of reciprocations, it goes up level by level until all heat exchangers with serious ash accumulation are cleaned, and then the ash cleaning is carried out from top to bottom.

[0036] The ash cleaning device provided by the present application includes a jet brushing device and a drive device. The jet brushing device includes a combination module of a plurality of brush sweeping devices + nozzles. The drive device can drive the jet brushing device to displace along the length direction of the heat exchange tubes. This composite ash cleaning method combines the ability of the brush sweeping device to loosen sticky and strongly adherent ash, and the jet blowing effect on the residual ash on the surfaces of multiple heat exchange tubes in the column where the jet brushing point is located. The jet brushing device reciprocates along the axial direction of the heat exchange tubes, which is beneficial to effectively peeling off stubborn ash or slag layers and there is no ash cleaning dead angle. In addition, the brush sweeping device is wear-resistant, high-temperature resistant, and insulating, and can avoid static electricity from generating electric sparks, thereby achieving an explosion-proof effect.

[0037] The jet blowing angle is set between the nozzle and the axis of the heat exchange tube; the jet blowing angle is set circumferentially with respect to the cross-section of the heat exchange tube, and the air flow coverage range is expanded: the setting of the jet blowing angle enables the air flow to cover more areas of the heat exchange tube and reduces dead angles. Inducing secondary air flow: Oblique jet blowing is beneficial to more effectively induce the surrounding flue gas and increase the total amount of ash cleaning air flow. Improving the utilization rate of jet blowing energy: Oblique jet blowing reduces the ineffective energy loss of direct impact, prolongs the effective ash cleaning time of the jet blowing air flow, and expands the air flow coverage range.

[0038] Hierarchical control, spraying and brushing from top to bottom, can guide the dust to fall, more in line with the law of dust settlement, reduce secondary adsorption, improve the thoroughness of dust cleaning; in addition, hierarchical control may allow dust cleaning layer by layer, reduce the fluctuation of system resistance, and maintain stable operation.

[0039] When the dust accumulation is relatively serious, a blowing scheme from bottom to top is adopted to first remove the dust accumulation in the lower layer to leave a falling channel for the dust accumulation in the upper layer.

[0040] Using the clean flue gas after dust removal as the blowing gas, compared with using nitrogen as the blowing gas, on the one hand, it can reduce the consumption of nitrogen and other substances, thereby reducing costs; on the other hand, the impact on the components of the converter flue gas is reduced, for example, avoiding affecting the CO content, calorific value, etc. of the flue gas. Description of the Drawings

[0041] Figure 1 Schematic diagram of the converter flue gas purification and waste heat recovery process provided by the present invention;

[0042] Figure 2 Schematic diagram of the heat exchange tube and dust cleaning spraying and brushing device of a certain stage heat exchanger of the converter waste heat boiler provided by the present invention;

[0043] Figure 3 Top view schematic diagram of the heat exchange tube and dust cleaning spraying and brushing device of a certain stage heat exchanger of the converter waste heat boiler provided by the present invention;

[0044] Figure 4 Schematic diagram of the blowing and brushing device for dust cleaning of the waste heat boiler;

[0045] Figure 5 Partial schematic diagram of the type I blowing and brushing device (blowing and brushing a single layer of heat exchange tubes);

[0046] Figure 6 Partial schematic diagram of the type II blowing and brushing device (blowing and brushing double layers of heat exchange tubes).

[0047] The meanings of the reference numerals are as follows: 1 converter; 2 flue gas; 3 cooling flue; 4 waste heat boiler: 40 heat exchange tubes; 41 spraying and brushing device: 410 blowing gas main pipe, 411 blowing gas branch pipe, 412 collar, 413 brushing device, 414 nozzle; 42 fixed seal; 43 telescopic seal; 44 blowing gas header pipe; 45 drive device; 46 blowing gas grading valve; 47 blowing gas hose; 48 heat exchange tube support plate; 49 housing; 491 inlet gas temperature measuring point; 492 pressure inlet measuring point; 493 outlet flue gas temperature measuring point; 494 pressure outlet measuring point; 5 dust removal device; 6 blowing gas storage tank; 7 blowing gas main valve. Detailed Embodiments

[0048] To make the purpose, technical solution and advantages of the present application clearer, the following will further describe the embodiments of the present application in detail with reference to the drawings.

[0049] First, embodiments of the present application will be introduced below with reference to the accompanying drawings.

[0050] As Figures 2 to 6 shown, the waste heat boiler 4 includes multiple groups of heat exchange tubes 40, heat exchange tube support plates 48, and a housing 49; meanwhile, a spraying device 41 for cleaning the heat exchange tubes, a fixed seal 42, a telescopic seal 43, multiple groups of air injection header pipes 44, a transmission device 45, an air injection grading valve 46, and an air injection hose 47 are provided.

[0051] Among them, a single group of heat exchange tubes 40 extends horizontally, and different groups of heat exchange tubes 40 are arranged at intervals in the vertical direction; multiple heat exchange tube support plates 48 are arranged vertically and penetrate multiple groups of heat exchange tubes 40; the heat exchange tube support plates 48 are evenly spaced.

[0052] On the outer side of the housing 49, a transmission device 45 is provided at one end in the extending direction of the spraying device 41.

[0053] Each group of air injection header pipes 44 corresponds to a transmission device 45; the air injection grading valve 46 corresponding to each group of air injection header pipes 44 is connected to the air injection header pipe 44 through an air injection hose 47; different groups of air injection header pipes 44 are arranged up and down in the same vertical plane.

[0054] A telescopic seal 43 and a fixed seal 42 are also provided between the transmission device 45 and the spraying device 41; among them, the fixed seal 42 is arranged at the junction of the housing 49 and the spraying device 41; the telescopic seal 43 is arranged between the fixed seal 42 and the transmission device 45 and can stretch and contract with the horizontal movement of the transmission device 45.

[0055] Among them, the transmission device 45 is used to drive the spraying device 41 to horizontally displace; during the process of driving the spraying device 41 to displace, the fixed seal 42 and the telescopic seal 43 ensure the sealing performance of the waste heat boiler 4, achieve double sealing, and ensure the isolation of flue gas from the atmospheric environment; meanwhile, the telescopic seal 43 is used to absorb the horizontal displacement of the spraying device 41; the air injection hose 47 is used to fix the connection between the air injection pipeline and the spraying device 41 and ensure the flexibility of the horizontal displacement of the spraying device 41; when the flue gas is an inflammable and explosive gas such as converter gas, the injected gas is nitrogen.

[0056] As Figures 2 to 6 shown, the spraying device 41 includes an air injection main pipe 410, air injection branch pipes 411, a collar 412, a brushing device 413, and nozzles 414.

[0057] The air injection header pipe 44 is connected to multiple air injection main pipes 410.

[0058] Among them, there are multiple main blowing pipes 410, which are horizontally arranged between the heat exchange pipes 40, and the main blowing pipes 410 are in the same extension direction as the heat exchange pipes 40; at least one main blowing pipe 410 is arranged between two adjacent upper and lower heat exchange pipes 40; it should be noted that in some places with serious ash accumulation, or for a single heat exchange pipe 40 at the top layer, it corresponds to a main blowing pipe 410 alone;

[0059] A plurality of blowing branch pipes 411 are vertically arranged at intervals on the main blowing pipe 410; the main blowing pipe 410 and the blowing branch pipes 411 form a criss-cross layout form; at least one blowing branch pipe 411 is arranged between two adjacent heat exchange pipe support plates 48;

[0060] A plurality of collars 412 are arranged at intervals on the blowing branch pipe 411; each collar 412 fixes a brushing device 413; a nozzle 414 is arranged beside the brushing device 413;

[0061] As Figures 2 to 6 shown, the heat exchange pipe support plate 48 divides the length of the heat exchange pipe into several intervals with smaller sizes, and the interval size can be seen in the Figure 2 dimension "S" in. The spraying and brushing points of the spraying and brushing device can be set at multiple places to realize the short-stroke reciprocating motion of the spraying and brushing device, while achieving the ash cleaning effect, reducing the occupied space of the reciprocating motion of the spraying and brushing device outside the boiler.

[0062] The spraying and brushing device 41 includes two types: type I spraying and brushing device and type II spraying and brushing device; among them, the type I spraying and brushing device is used to spray and brush a single layer of heat exchange pipes, that is, each main blowing pipe 410 corresponds to a heat exchange pipe; the type II spraying and brushing device is used to spray and brush two layers of heat exchange pipes at the same time, that is, only one main blowing pipe 410 is arranged between two heat exchange pipes; for the specific structural setting method, please refer to Figure 5 and Figure 6 . Figure 5 and Figure 6 shown. The brushing device + nozzle is a preferred embodiment. This composite ash cleaning method combines the ability of the brushing device to loosen sticky and strongly adherent ash, and the blowing effect on the residual ash on the surfaces of multiple heat exchange pipes in the column where the spraying and brushing point is located. The spraying and brushing device 41 reciprocates along the axial direction of the heat exchange pipe, which is beneficial to effectively peeling off stubborn ash or slag layers, and there is no ash cleaning dead angle. In addition, in the case of flammable and explosive flue gas, the brushing device is a ceramic brush, and the ceramic material has the advantage of insulation. The ceramic brush is wear-resistant, high-temperature resistant, and insulating, and can avoid static electricity from generating electric sparks, thus achieving an explosion-proof effect.

[0063] The transmission device 45 can be driven by air pressure, a hydraulic cylinder or a motor, and specifically, it can adopt, for example, a lead screw drive, a wire rope drive, a sprocket chain drive, etc. to drive the spraying and brushing device 41 to reciprocate.

[0064] The range of the blowing angle α between the nozzle 414 and the axis of the heat exchange pipe can be seen inFigure 5 , Figure 6 is 15° to 45°, preferably 30°; the range of the blowing angle β of the nozzle 414 in the circumferential direction of the cross-section of the heat exchange tube is shown in Figure 5 , Figure 6 is 60° to 120°, preferably 90°.

[0065] This setting method of the nozzle has the following advantages:

[0066] Expand the air flow coverage range and reduce the dead corners of soot cleaning:

[0067] The blowing angle α between the nozzle and the axis of the heat exchange tube strengthens the blowing effect on the surfaces of multiple heat exchange tubes in this row; the blowing angle β between the nozzle and the circumferential direction of the cross-section of the heat exchange tube increases the blowing range in the length direction of the heat exchange tube. The air flow enters the space of the heat exchange tube bundle in a non-vertical direction, guiding the air flow to adhere and diffuse along the wall surface of the heat exchange tube, forming a wider purging coverage range and effectively avoiding the accumulation and residue of ash on the heat exchange tube.

[0068] Enhance the air flow induction and mixing effect:

[0069] The obliquely blown air flow generates a strong vortex effect and entrains more secondary air flows, inducing the surrounding flue gas to participate in the soot cleaning process. Due to the better entrainment efficiency of the oblique blowing, the overall kinetic energy of the soot cleaning air flow is increased.

[0070] It allows the air flow to diffuse to the surface of the heat exchange tube with less kinetic energy loss and reduces the ineffective energy loss of direct impact. At the same blowing pressure, the effective soot cleaning time of the obliquely blown air flow is extended and the energy utilization rate is improved.

[0071] An inlet gas temperature measuring point 491 is set at the inlet of the heat exchange tube, and an outlet flue gas temperature measuring point 493 is set at the outlet; a pressure inlet measuring point 492 is set at the inlet of the heat exchange tube, and a pressure outlet measuring point 494 is set at the outlet of the heat exchange tube;

[0072] See Figure 1 , the flue gas 2 discharged from the converter 1 enters the waste heat boiler 4 to further recover heat after passing through the cooling flue 3, and the outlet flue gas enters the dust removal device and then enters the subsequent process.

[0073] Preferably, the relatively clean flue gas after dust removal is used as the blowing gas, and the blowing gas is nitrogen. Specifically, the flue gas after dust removal is led out after the dust removal device 5, compressed and stored in the blowing gas storage tank 6, and then this flue gas is used for blowing.

[0074] Preferably, the blowing gas grading valve 46 is a shock wave generating valve, and the gas recycled in the blowing gas storage tank 6 is stored at a pressure of 0.6 to 0.8 MPa. When soot blowing operation is required, the high-pressure gas is quickly released through the shock wave generating valve to form a strong shock wave air flow at the nozzle 414 to blow away the dust and impurities on the surface of the heat exchange tube 40.

[0075] In some embodiments, the spray gas main pipe is also provided with a spraying device.

[0076] The present application also provides an intelligent method for cleaning ash from a waste heat boiler, and the method is implemented based on the device provided by the present application;

[0077] The temperature measuring points 491 of the inlet gas, the temperature measuring point 493 of the outlet flue gas, the pressure inlet measuring point 492, and the pressure outlet measuring point 494 are monitored in real time to monitor the temperature drop and resistance drop of the flue gas in the waste heat boiler;

[0078] When the temperature drop and resistance drop of the flue gas are within the set normal threshold range, an automatic blowing and brushing program is set, and the ash cleaning work is carried out periodically at a fixed frequency. At the same time, it is judged whether there is ash accumulation in the heat exchange tube bundle;

[0079] Once ash accumulation occurs, the ash cleaning is started until the temperature drop and resistance drop of the flue gas return to within the normal threshold.

[0080] If any one of the temperature drop and resistance drop of a certain stage of heat exchange tube exceeds 15% of the normal threshold, it is considered that there is ash accumulation.

[0081] If it is judged that there is ash accumulation, the jet air classification valve 46 and the transmission device 45 are controlled to open for ash cleaning. Specifically, the corresponding jet air classification valve 46 opens, and the jet air enters the spraying device 41 and is ejected outward through the nozzle 414; the transmission device 45 drives the jet gas main pipe 410 to move horizontally, thereby driving the brushing device 413 to move horizontally.

[0082] For example, if the temperature and resistance drop parameters between the inlet and outlet of a certain stage of heat exchanger are greater than 15% of the set temperature, it is judged that there may be ash accumulation in the heat exchanger of this stage, and the jet air classification valve 46 and the transmission device 45 of this stage of heat exchanger are controlled to start working. When the temperature and resistance drop parameters return to normal, the jet air classification valve 46 and the transmission device 45 of this stage of heat exchanger are stopped from working.

[0083] Generally, the low-temperature heat exchange section is the part where ash accumulation is more serious. Taking the last-stage heat exchanger as an example: it is set that the flue gas temperature discharged at the initial stage of operation of this stage of heat exchanger is 180 °C and the resistance drop is 120 Pa; at a certain stage during the operation process, the flue gas temperature discharged from this stage of heat exchanger is 215 °C and the resistance drop is 160 Pa, then it is judged that there is an ash accumulation condition in the equipment, and the ash accumulation program needs to be started and the frequency of soot blowing is increased.

[0084] Soot blowing is carried out periodically, or during the overall ash cleaning process, the ash cleaning is carried out in groups.

[0085] The jet system also includes a jet gas main valve and a jet gas classification valve, and the jet gas classification valve is used to control the top-down jet.

[0086] The jet blowing and classification valve at the first level of the top layer is opened first. The brush sweeping device 413 is horizontally moved under the drive of the transmission device. After reaching the set number of reciprocations, the second-level jet blowing and classification valve is opened and spraying and brushing are carried out; and so on until all the heat exchangers are cleaned. This spraying and brushing method can guide the dust to fall, more conform to the law of dust settlement, reduce secondary adsorption, and improve the thoroughness of dust cleaning; in addition, hierarchical control may allow layer-by-layer dust cleaning, reduce the resistance fluctuation of the flue gas system, and maintain stable operation.

[0087] Preferably, when the ash accumulation is relatively serious, a group-by-group dust cleaning method from bottom to top is adopted. The jet blowing and classification valve at the bottom layer is opened first. The brush sweeping device 413 is horizontally moved under the drive of the transmission device. After reaching the set number of reciprocations, it goes up level by level until all the heat exchangers with serious ash accumulation are cleaned, and then the dust cleaning is carried out from top to bottom. First, the ash accumulation in the lower layer is removed to leave a falling channel for the ash accumulation in the upper layer, preventing all the ash accumulation in the upper layer from falling onto the lower heat exchange tubes and even causing blockage.

[0088] The device and method provided by the present application can be applied to a variety of scenarios, including converter flue gas, electric furnace flue gas, sintering flue gas, etc. in the iron and steel metallurgy industry; calcium carbide furnace flue gas; coal-fired / power generation boiler flue gas in the power and energy industry; coal gasification flue gas; cement and glass production kiln flue gas in the building materials industry; waste incineration and solid waste treatment flue gas; non-ferrous metal smelting flue gas, etc.

[0089] The present application is particularly suitable for the dust cleaning occasions of bare tubes, longitudinal straight fin tubes, and heat exchange tube bundles of boilers (heat exchangers) arranged in rows with toxic, flammable, explosive environments, high dust content, and stubborn ash accumulation.

[0090] The above-described embodiments of the present application do not constitute a limitation on the protection scope of the present application.

Claims

1. An intelligent soot cleaning device for waste heat boilers, characterized in that, The dust cleaning device is used for a waste heat boiler (4), the waste heat boiler (4) comprising a plurality of groups of heat exchange tubes (40) and a shell (49), wherein a single group of heat exchange tubes (40) extends transversely, and different groups of heat exchange tubes (40) are arranged at intervals in the vertical direction; the outer layer of the waste heat boiler (4) is the shell (49); The dust cleaning device includes a brushing device (41), a blowing air delivery system, and a transmission device (45); The spray brush device (41) includes a nozzle (414) and a brushing device (413), the spray brush device (41) is arranged on the spray air pipeline, the spray air is sprayed from the nozzle (414) along the spray air pipeline in the spray air delivery system, and a transmission device (45) is arranged at one end of the spray air pipeline in the direction of extension of the axis of the heat exchange tube (40), and the transmission device (45) is used to drive the spray brush device (41) to move back and forth along the direction of extension of the axis of the heat exchange tube (40); The dust cleaning device also includes a monitoring and control module, which includes a controller, a temperature sensor, and a pressure sensor. The controller controls the brushing device (41), the air blowing system, and the transmission device (45) according to the values of the temperature sensor and the pressure sensor.

2. The dust cleaning device according to claim 1, characterized in that: The included angle α between the nozzle (414) and the cross section of the blowing gas duct where the nozzle (414) is located ranges from 15° to 45°; the included angle β between the nozzle (414) and the longitudinal axis of the cross section where the nozzle (414) is located ranges from 60° to 120°.

3. The dust cleaning device according to claim 1 or 2, characterized in that: The injection gas pipeline includes an injection gas main pipe (410) and an injection gas branch pipe (411); The axis of the injection gas main pipe (410) is parallel to the axis of the heat exchange tube (40), one or more injection gas branch pipes (411) are vertically connected to the injection gas main pipe (410), and the plane formed by the injection gas branch pipes (411) and the injection gas main pipe (410) is parallel to the axis of the heat exchange tube (40), wherein the spray brush device is arranged at the injection gas branch pipe, and the brushing device (413) is arranged corresponding to the heat exchange tube; A transmission device (45) is provided at one end of the injection air pipeline extending along the axis of the heat exchange tube (40).

4. The dust cleaning device according to claim 1 or 2, characterized in that The brushing device (413) is arranged on the blowing air pipeline via a collar.

5. The dust cleaning device according to claim 1 or 2, characterized in that, The spray brushing device (41) includes two types: a type I blowing brushing device and a type II blowing brushing device; wherein the type I blowing brushing device is used to blow brush single-layer heat exchange tubes, that is, each blowing air main pipe (410) corresponds to one heat exchange tube; the type II blowing brushing device is used to blow brush double-layer heat exchange tubes at the same time, that is, only one blowing air main pipe (410) is set between the two heat exchange tubes.

6. The dust cleaning device according to claim 3, wherein The injection gas delivery system also includes an injection gas classification valve (46), an injection gas hose (47), and an injection gas header pipe (44); Wherein, the injection gas header pipe (44) is connected to a plurality of injection gas main pipes (410); The injection gas classification valve (46) and the injection gas header pipe (44) are connected by an injection gas hose (47).

7. The dust cleaning device according to claim 1 or 2, wherein A seal is provided between the blowing gas pipeline passing through the waste heat boiler housing and the housing (49). The seal includes an expansion seal (43) and a fixed seal (42). Among them, the fixed seal (42) connects the housing (49) to the blowing gas pipeline; the expansion seal (43) connects the fixed seal (42) to the blowing gas pipeline, and the expansion seal can expand and contract with the movement of the transmission device (45) and the blowing gas pipeline.

8. The dust cleaning device according to claim 1, characterized in that An inlet gas temperature measuring point (491) is provided at the inlet of the heat exchange tube, and an outlet flue gas temperature measuring point (493) is provided at the outlet; a pressure inlet measuring point (492) is provided at the inlet of the heat exchange tube, and a pressure outlet measuring point (494) is provided at the outlet of the heat exchange tube.

9. The dust cleaning device according to claim 1, wherein The blowing gas includes the flue gas after dust removal.

10. A method for cleaning ash from an intelligent waste heat boiler, the method being implemented based on the device provided in claims 1 to 9; characterized in that, The method includes: The monitoring and control module performs real-time monitoring to monitor the temperature drop and resistance drop of the flue gas in the waste heat boiler. When the temperature drop and resistance drop of the flue gas are within the set normal threshold range, the soot blowing work is carried out periodically at a fixed frequency, and at the same time, it is judged whether there is ash accumulation in the heat exchange tube bundle. Once ash accumulation occurs, the soot blowing is started until the temperature drop and resistance drop of the flue gas return to within the normal threshold.

11. The method according to claim 10, wherein If any value of the temperature drop and resistance drop of a certain stage of heat exchange tube exceeds 15% of the normal threshold, it is considered that there is ash accumulation. If it is judged that there is ash accumulation, control the blowing gas grading valve (46) and the transmission device (45) to start soot blowing: the corresponding blowing gas grading valve (46) is opened, the blowing gas enters the spraying device (41), and is sprayed out through the nozzle (414); the transmission device (45) drives the blowing gas main pipe (410) to move horizontally, thereby driving the brushing device (413) to move horizontally.

12. The method according to claim 10, wherein During periodic soot blowing or during the overall soot blowing process, the soot blowing is carried out in groups. The process of soot blowing in groups includes: The blowing gas grading valve of the first stage of the topmost layer is opened first, and the brushing device (413) is moved horizontally under the drive of the transmission device. After reaching the set number of reciprocations, the blowing gas grading valve of the second stage is opened and sprayed; and so on until all the heat exchangers are soot blown.

13. The method according to claim 10, wherein When the ash accumulation is serious, the bottom-up grouping soot blowing method is adopted. First, the blowing gas grading valve of the bottommost layer is opened, and the brushing device (413) is moved horizontally under the drive of the transmission device. After reaching the set number of reciprocations, it goes up level by level until all the heat exchangers with serious ash accumulation are soot blown, and then the soot blowing is carried out from top to bottom.

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