Device and method for preventing ash deposition in horizontal flue of boiler

Abstract

The invention provides an ash deposition prevention device and method for a horizontal flue of a boiler. The ash deposition prevention device for the horizontal flue of the boiler comprises a smoke taking pipeline, a boiler smoke fan, a smoke dust separation assembly, an ash collecting hopper, an ash discharging pipe and a purging assembly. The smoke taking pipeline is connected between the boiler tail gas flue and the purging assembly and used for conveying smoke in the boiler tail gas flue to the purging assembly. The furnace smoke fan is arranged on the smoke taking pipeline and used for pumping smoke. The smoke dust separation assembly is arranged on the smoke taking pipeline and used for separating dust in the smoke. The dust collecting hopper is arranged on the smoke taking pipeline and used for collecting the separated dust. And the ash discharge pipe is communicated with the ash collecting hopper and is used for discharging the collected ash. The purging assembly is arranged at the bottom of the horizontal flue of the boiler and used for spraying out smoke to purge accumulated dust in the horizontal flue of the boiler, and the air spraying speed of the purging assembly is 3-5 m / s. The device can realize continuous purging of accumulated ash in the horizontal flue of the boiler, and can reduce the risk of pipe wall leakage caused by abrasion of a purging medium to the pipe wall.

Description

Technical Field

[0001] This application relates to the technical field of boilers, and more particularly, to a boiler horizontal flue anti-ash accumulation device and method. Background Art

[0002] In current boiler maintenance practices, devices such as wind cap type, disc type soot blowers or rotatable fixed steam soot blowers are mostly installed on the bottom surface of the horizontal flue, and high-pressure media (such as compressed air, high-temperature steam) are used for purging to remove the ash accumulated on the heating surface. However, the high-pressure media are at the MPa level, while the boiler flue gas is only at the Pa level. The high-speed injection of the foreign media will bring a very strong "sandblasting and grinding" effect, causing significant wear to the metal pipe wall. After long-term use, this wear will cause the pipe wall to gradually become thinner, greatly increasing the risk of leakage. If measures such as reducing the pressure or frequency are taken, it will also reduce the effect of soot blowing and slag removal, and even the situation of "soot blowing is not as fast as ash falling" may occur. Summary of the Invention

[0003] At least one embodiment of this application provides a boiler horizontal flue anti-ash accumulation device and method. The device can achieve continuous purging of the ash accumulated in the boiler horizontal flue and can reduce the risk of leakage of the pipe wall caused by the wear of the purging medium on the pipe wall.

[0004] In a first aspect, an embodiment of this application provides a boiler horizontal flue anti-ash accumulation device, which includes: a smoke extraction pipe, a furnace smoke fan, a dust separation component, an ash collection hopper, an ash discharge pipe, and a purging component;

[0005] The smoke extraction pipe is connected between the boiler tail gas flue and the purging component, and the smoke extraction pipe is used to send the flue gas in the boiler tail gas flue to the purging component;

[0006] The furnace smoke fan is arranged in the smoke extraction pipe, and the furnace smoke fan is used to pump the flue gas;

[0007] The dust separation component is arranged in the smoke extraction pipe, and the dust separation component is used to separate the dust in the flue gas;

[0008] The ash collection hopper is arranged in the smoke extraction pipe, and the ash collection hopper is used to collect the separated dust;

[0009] The ash discharge pipe is communicated with the ash collection hopper, and the ash discharge pipe is used to discharge the collected dust;

[0010] The purging component is arranged at the bottom of the boiler horizontal flue, and the purging component is used to eject the flue gas to purge the ash accumulated in the boiler horizontal flue, and the jet speed of the purging component is 3 - 5 m / s.

[0011] In an alternative embodiment, the flue gas extraction pipeline is specifically connected between the outlet flue of the boiler denitration device and the purging assembly, and is used to send the flue gas in the outlet flue of the boiler denitration device to the purging assembly.

[0012] In an alternative embodiment, the flue gas extraction pipeline includes a right-angle pipe section, which is used to deflect the flue gas to separate the dust in the flue gas.

[0013] In an alternative embodiment, the flue gas extraction pipeline includes a flue gas extraction port that extends into the boiler tail gas flue, and the orientation of the flue gas extraction port is consistent with the flow direction of the flue gas in the boiler tail gas flue.

[0014] In an alternative embodiment, the flue gas extraction pipeline includes an inlet pipe section and an outlet pipe section. The inlet pipe section is connected to the inlet of the furnace flue gas fan and is provided with an inlet valve, and the outlet pipe section is connected to the outlet of the furnace flue gas fan and is provided with an outlet valve.

[0015] In an alternative embodiment, both the inlet valve and the outlet valve are provided with sealing air.

[0016] In an alternative embodiment, the number of the furnace flue gas fans is multiple, and the multiple furnace flue gas fans are arranged in parallel on the flue gas extraction pipeline.

[0017] In an alternative embodiment, the purging assembly includes a flue gas access pipeline and a flue gas nozzle. The flue gas access pipeline is arranged in the horizontal flue of the boiler, and the flue gas nozzle is arranged on the flue gas access pipeline and is used to eject the flue gas.

[0018] In an alternative embodiment, the purging assembly further includes a deflector plate, which is inclined at the bottom of the horizontal flue of the boiler and is used to deflect and upwardly guide the ejected flue gas.

[0019] In a second aspect, the embodiment of the present application further provides a method for preventing ash accumulation in the horizontal flue of a boiler, which is applicable to the boiler horizontal flue ash prevention device described above. The method includes: the flue gas extraction pipeline extracts the flue gas from the boiler tail gas flue. After the dust in the flue gas is separated by the dust separation assembly, under the action of the furnace flue gas fan, it is sent to the purging assembly, and the purging assembly ejects the flue gas at a speed of 3-5 m / s to purge the accumulated ash in the horizontal flue of the boiler.

[0020] The above technical solution of the present application has the following beneficial technical effects:

[0021] The anti - ash - accumulation device for the boiler's horizontal flue in the embodiment of the present application uses flue gas with low speed, low dust content, and the same properties to blow - sweep the bottom of the horizontal flue, which can completely eliminate the severe erosion and wear problems brought to the flue by high - speed medium soot blowing. Thus, it can reduce the risk of tube wall leakage caused by the wear of the blowing medium on the tube wall. At the same time, since the flue gas in the boiler tail gas flue can be recycled, the device can continuously blow - sweep the accumulated ash, thereby avoiding the situation where the ash - accumulation speed is greater than the soot - blowing speed.

[0022] To make the above - mentioned objects, features, and advantages of the present application more obvious and understandable, the following specifically gives preferred embodiments and, in conjunction with the accompanying drawings, makes detailed descriptions as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] To more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required to be used in the embodiments. Here, the drawings are incorporated into the specification and constitute a part of this specification. These drawings show the embodiments that conform to the present application and, together with the specification, are used to illustrate the technical solutions of the present application. It should be understood that the following drawings only show some embodiments of the present application and should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other relevant drawings can also be obtained based on these drawings.

[0024] Figure 1 Shows a schematic diagram of an anti - ash - accumulation device for a boiler's horizontal flue provided by an embodiment of the present application;

[0025] Figure 2 Shows Figure 1 the schematic diagram of the deflector in

[0026] In the figure:

[0027] 1. Smoke - taking pipeline; 11. Right - angled pipe section; 12. Smoke - taking port; 13. Inlet pipe section; 131. Inlet valve; 132. Inlet door sealing air duct; 133. Inlet sealing air damper; 14. Outlet pipe section; 141. Outlet valve; 142. Outlet door sealing air duct; 143. Outlet sealing air damper; 2. Furnace flue gas fan; 3. Dust separation component; 4. Ash hopper; 5. Ash discharge pipe; 6. Flue gas main pipe; 7. Flue gas branch pipe; 8. Flue gas nozzle; 9. Deflector; 100. Boiler; 110. Horizontal flue; 120. Tail gas flue; 130. Economizer ash hopper. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] Now, various exemplary embodiments of the present application will be described in detail with reference to the drawings. It should be noted that: Unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present application.

[0029] Embodiments of the present application will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals indicate the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present application and should not be construed as limiting the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts belong to the scope of protection of the present application.

[0030] The terms "first" and "second" in the description and claims of the present application may explicitly or implicitly include one or more of such features. In the description of the present application, unless otherwise specified, the meaning of "a plurality" is two or more. In addition, "and / or" in the description and claims means at least one of the connected objects. The character " / " generally indicates an "or" relationship between the associated objects before and after.

[0031] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the present application.

[0032] In the description of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "mounted", "connected" and "connected" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0033] Reference Figure 1 and Figure 2, an embodiment of the present application provides a boiler horizontal flue anti - ash - accumulation device, which includes: a smoke - taking pipeline 1, a furnace - flue fan 2, a dust - separation assembly 3, an ash - collecting hopper 4, an ash - discharging pipe 5, and a purging assembly. The smoke - taking pipeline 1 is connected between the tail - gas flue 120 of the boiler 100 and the purging assembly, and the smoke - taking pipeline 1 is used to send the flue gas in the tail - gas flue 120 of the boiler 100 to the purging assembly. The furnace - flue fan 2 is arranged in the smoke - taking pipeline 1, and the furnace - flue fan 2 is used to pump the flue gas. The dust - separation assembly 3 is arranged in the smoke - taking pipeline 1, and the dust - separation assembly 3 is used to separate the dust in the flue gas. The ash - collecting hopper 4 is arranged in the smoke - taking pipeline 1, and the ash - collecting hopper 4 is used to collect the separated dust. The ash - discharging pipe 5 is communicated with the ash - collecting hopper 4, and the ash - discharging pipe 5 is used to discharge the collected dust. The purging assembly is arranged at the bottom of the horizontal flue 110 of the boiler 100, and the purging assembly is used to eject flue gas to purge the ash - accumulation in the horizontal flue 110 of the boiler 100, and the jet speed of the purging assembly is 3 - 5 m / s.

[0034] During use, the smoke - taking pipeline 1 extracts the flue gas from the tail - gas flue 120 of the boiler 100. After the flue gas is separated from the dust by the dust - separation assembly 3, it is sent to the purging assembly under the action of the furnace - flue fan 2. The purging assembly ejects the flue gas at a speed of 3 - 5 m / s to purge the ash - accumulation in the horizontal flue 110 of the boiler 100. At the same time, the separated dust can fall into the ash hopper and then be discharged through the dust - discharging pipe.

[0035] Compared with using a high - pressure and high - flow - rate purging medium, this device uses low - speed, low - dust flue gas with the same properties to purge the bottom of the horizontal flue 110, which can completely eliminate the severe erosion and wear problems brought by high - speed medium soot blowing to the flue, thus reducing the risk of tube wall leakage caused by the purging medium wearing the tube wall. At the same time, since the flue gas in the tail - gas flue 120 of the boiler 100 can be recycled, the device can continuously purge the ash - accumulation, thus avoiding the situation where the ash - accumulation speed is greater than the soot - blowing speed.

[0036] In some embodiments, the smoke - taking pipeline 1 is specifically connected between the outlet flue of the denitration device of the boiler 100 and the purging assembly, and the smoke - taking pipeline 1 is used to send the flue gas in the outlet flue of the denitration device of the boiler 100 to the purging assembly. That is to say, the tail - gas flue 120 of the boiler is the outlet flue of the denitration device (denitration catalytic reactor) of the boiler 100, and the flue gas taken out by the smoke - taking pipeline 1 is the flue gas after denitration treatment. The temperature of the flue gas after denitration is usually still relatively high, which helps to maintain the temperature of the heating surface, avoid the sudden temperature drop caused by the entry of cold air, and thus prevent stress damage caused by temperature difference. At the same time, the higher temperature also helps to enhance the fluidity of the particulate matter, facilitating better ash removal. In addition, the content of nitrogen oxides (NOx) in the flue gas after denitration treatment is significantly reduced, which can effectively reduce the corrosion risk.

[0037] In some embodiments, the smoke extraction duct 1 includes a right-angle duct section 11 which is used to deflect the flue gas so as to separate the dust in the flue gas. Specifically, the right-angle duct section 11 can be located at one end of the smoke extraction duct 1 close to the tail gas flue 120 of the boiler 100. When the flue gas passes through the right-angle duct section 11, the dust in the flue gas is very likely to impact the duct wall under the action of centrifugal force and thus be separated from the flue gas. In this way, the dust content in the flue gas can be reduced, and the abrasion of the subsequent flue gas on the horizontal duct can be decreased. In a specific implementation, the ash hopper 4 can be arranged at the corner position of the right-angle duct section 11, which enables the dust separated from the flue gas to be collected and discharged in time, avoiding the occurrence of secondary entrainment.

[0038] In some embodiments, the smoke extraction duct 1 includes a smoke extraction port 12 which extends into the tail gas flue 120 of the boiler 100, and the orientation of the smoke extraction port 12 is consistent with the direction of the flue gas flow in the tail gas flue 120 of the boiler 100. Specifically, the smoke extraction port 12 can be in the form of a triangle or an elbow, with one side of the windward surface being closed and the other side of the leeward surface being open. In this embodiment, it is shown that the smoke extraction port 12 is arranged downward. When the flue gas with entrained fly ash flows downward, the fly ash with a larger density continues to fall, while the flue gas with a smaller density can enter the smoke extraction duct 1 through the smoke extraction port 12. In this way, the dust entering the smoke extraction duct 1 can be reduced, thus reducing the abrasion of the flue gas on the smoke extraction duct 1 and the furnace smoke fan 2.

[0039] In some embodiments, the smoke extraction duct 1 includes an inlet duct section 13 and an outlet duct section 14. The inlet duct section 13 is connected to the smoke inlet of the furnace smoke fan 2 and is provided with an inlet valve 131, and the outlet duct section 14 is connected to the smoke outlet of the furnace smoke fan 2 and is provided with an outlet valve 141. During specific use, since the temperature of the flue gas is relatively high (350 - 380 °C), after the equipment stops running, the inlet valve 131 and the outlet valve 141 can be closed, which can prevent the heat transfer in the flue of the boiler 100 from being transferred to the furnace smoke fan 2 and its accessories, affecting the normal operation of the boiler 100.

[0040] In some embodiments, both the inlet valve 131 and the outlet valve 141 are provided with sealing air. Specifically, the inlet valve 131 can be provided with an inlet door sealing air duct 132 which can convey sealing air to the inlet valve 131 to prevent the leakage of flue gas from the inlet valve 131. Similarly, the outlet valve 141 can be provided with an outlet door sealing air duct 142 which can convey sealing air to the outlet valve 141 to prevent the leakage of flue gas from the outlet valve 141. In a specific implementation, the inlet door sealing air duct 132 can be provided with an inlet sealing air door 133, and the outlet door sealing air duct 142 can be provided with an outlet sealing air door 143 to facilitate the control of the sealing air.

[0041] In some embodiments, the furnace flue gas fan 2 is a variable frequency fan. During specific use, the operator can remotely operate the frequency converter of the variable frequency fan to adjust the impeller speed, and finally achieve the regulation of the fan output. In a specific implementation, the blades of the furnace flue gas fan 2 can be made of wear-resistant and corrosion-resistant alloy steel, and ceramic sheets can be pasted on the blades and other easily worn parts of the furnace flue gas fan 2 to achieve effects such as wear resistance and corrosion prevention.

[0042] In some embodiments, the number of the furnace flue gas fans 2 is multiple, and the multiple furnace flue gas fans 2 are arranged in parallel in the smoke extraction pipeline 1. This embodiment shows that the number of the furnace flue gas fans 2 is two. When one furnace flue gas fan 2 fails, the other furnace flue gas fan 2 can still continue to operate to ensure that the system will not completely fail.

[0043] In some embodiments, the dust separation assembly 3 can be a cyclone separator or an impact deflector 9 structure. Of course, this embodiment is not specifically limited.

[0044] In some embodiments, the dust separation assembly 3 is located at a position of the smoke extraction pipeline 1 close to the tail gas flue 120 of the boiler 100. During specific use, after the dust separation assembly 3 separates the dust, the dust content in the remaining flue gas is reduced, which can not only reduce the wear of the flue gas on the horizontal flue 110, but also reduce the wear on the smoke extraction pipeline 1 and the furnace flue gas fan 2, which is beneficial to extending the service life of the equipment.

[0045] In some embodiments, the dust separation assembly 3 can be arranged at the corner position of the right-angle pipe section 11. During specific use, the dust separated by the dust separation assembly 3 and the dust separated by the turning of the flue gas can both fall into the same ash hopper 4, which can reduce the number of ash hoppers 4 and dust discharge pipes used, is beneficial to simplifying the equipment structure, and reducing costs.

[0046] In some embodiments, a dust discharge valve can be arranged at the bottom of the ash hopper 4, and the dust discharge valve is used to open the ash hopper 4 for ash discharge. Specifically, by opening the dust discharge valve, the lower opening of the ash hopper 4 is opened, and the collected dust can fall into the dust discharge pipe through the lower opening of the ash hopper 4 and then be discharged through the dust discharge pipe. During specific setting, the dust discharge valve can be a gravity type flap valve or an electric door that can be remotely controlled. This embodiment is not specifically limited thereto.

[0047] In some embodiments, the dust discharge pipe is connected to the economizer ash hopper 130 of the boiler 100, and the dust discharge pipe is used to discharge the collected dust to the economizer ash hopper 130 of the boiler 100. Such a setting enables the collected dust to be discharged into the economizer ash hopper 130 of the boiler 100 through the dust discharge pipe, and then be discharged to the original pneumatic ash conveying system of the boiler 100 through the economizer ash hopper 130 to transport the dust away, which can simplify the structure of the equipment and is beneficial to reducing costs.

[0048] In some embodiments, the purging assembly includes a flue gas access pipe and a flue gas nozzle 8. The flue gas access pipe is disposed in the horizontal flue 110 of the boiler 100, and the flue gas nozzle 8 is disposed on the flue gas access pipe and is used for ejecting flue gas. During specific use, the smoke extraction pipe 1 supplies flue gas to the flue gas access pipe, and the flue gas is ejected through the flue gas nozzle 8 to purge the ash accumulated at the bottom of the horizontal pipe.

[0049] In one embodiment, the flue gas access pipe includes a main flue gas pipe 6 and a plurality of flue gas branch pipes 7. Each flue gas branch pipe 7 is communicated with the main flue gas pipe 6, and a flue gas nozzle 8 is disposed on each flue gas branch pipe 7. During specific installation, the flue gas branch pipes 7 are arranged at intervals along the gas flow direction of the horizontal flue 110. Each flue gas branch pipe 7 extends along the width direction of the horizontal flue 110, and a plurality of flue gas nozzles 8 are distributed at intervals on each flue gas branch pipe 7. With such an arrangement, the flue gas can evenly scour the ash accumulated at the bottom of the horizontal flue 110, which is beneficial to improving the purging effect. Of course, the setting mode of the flue gas access pipe can be selected according to the actual situation (such as the severity of ash falling in different parts of the horizontal flue 110), and is not limited to the above-discussed mode.

[0050] In some embodiments, the purging assembly further includes a deflector 9. The deflector 9 is inclined at the bottom of the horizontal flue 110 of the boiler 100 and is used for guiding the ejected flue gas upward obliquely. In this embodiment, the number of deflectors 9 is shown as multiple, and the multiple deflectors 9 and the multiple flue gas branch pipes 7 are alternately distributed. During specific use, the dust in the flue gas (i.e., the original flue gas in the horizontal flue 110) can be deposited on the deflector 9. The flue gas ejected from the flue gas nozzle 8 can blow the dust on the deflector 9 to a higher place along the deflector 9, and finally be carried away by the flue gas with a higher flow rate at a higher place (i.e., the original flue gas in the horizontal flue 110). In addition, the deflector 9 covers the bottom surface of the horizontal flue 110, which can protect the bottom surface (heating surface) of the horizontal flue 110 and avoid the wear and temperature difference stress caused by the direct contact between the ejected flue gas and the wall surface of the horizontal flue 110.

[0051] In some embodiments, as Figure 2 shown, one end of the deflector 9 is located on the flue gas branch pipe 7 to achieve inclination. That is to say, under the support of the flue gas branch pipe 7, one end of the deflector 9 is inclined upward. With such an arrangement, there is no need to additionally set up a support frame or bend the deflector 9, which is beneficial to simplifying the installation process and reducing costs.

[0052] For the boiler horizontal flue anti-ash accumulation device according to the embodiments of the present application, the furnace gas fan 2 and each valve can be remotely controlled, and the relevant control logic is built in the power plant DCS.

[0053] The start-up adjustment of the furnace gas fan 2 is as follows:

[0054] 1. When the coal quantity of the unit > 15 t / h and the air volume of the unit > 30% of the air volume under BMCR condition, with a 10-minute delay;

[0055] 2. The inlet valve 131 has been opened and the outlet valve 141 has been closed;

[0056] 3. The parameters of the fan oil station are normal (including parameters such as oil level, oil temperature, oil pressure, and bearing temperatures of the fan and motor);

[0057] 4. The motor switch and frequency converter of the furnace gas fan 2 have been powered on, and the status display on the DCS screen is normal;

[0058] 5. The inlet seal damper 133 and the outlet seal damper 143 are both opened, and the seal air pressure is normal.

[0059] After all the above conditions are met, the start permission of the furnace gas fan 2 in the DCS is issued, and the "Start" button on the screen starts to change to the "clickable" state.

[0060] On the DCS screen, click the "Start" button of the furnace gas fan 2, and the DCS control module will perform the following steps:

[0061] 1. Issue commands: Open the outlet valve 141 of the furnace gas fan 2. At the same time, issue the commands "Frequency conversion contactor switch on" and "Fan motor circuit breaker switch on". The judgment for the completion of this step is: The "fully opened" signal of the outlet valve 141 is received, the "switched on" signal of the frequency conversion contactor is received, and the "switched on" signal of the fan motor circuit breaker is received;

[0062] 2. After the previous step is completed, issue a command: Set the frequency converter command to 10.0 Hz. The judgment for the end of this step is: The frequency feedback of the frequency converter is 10 ± 2 Hz;

[0063] 3. After the previous step is completed, issue a command: Put another furnace gas fan 2 (standby fan) into interlock standby. The judgment for the end of this step is: The interlock standby button of the furnace gas fan 2 is "put into";

[0064] 4. After the judgment of the previous step is completed, issue a command: Put the output adjustment of the operating furnace gas fan 2 into automatic (i.e., the frequency of the frequency converter is automatically given by the program). The judgment for the completion of this step is: The output automatic of the furnace gas fan 2 is "put into";

[0065] 5. The start sequence control is completed, and the DCS screen displays "The furnace gas fan 2 starts successfully".

[0066] At the outlet flue of the denitration device, the flue gas is ash-removed for the first time through the smoke extraction port 12, and then travels along the smoke extraction pipeline 1. At the dust separation component 3, it is ash-removed again. At this time, the flue gas has been purified, and its dust content can meet the requirements for the long-term safe and stable operation of the furnace gas fan 2. The fly ash separated by the dust separation component 3 falls into the economizer ash hopper 130 under the action of gravity. The cleaned flue gas after ash removal passes through the main flue gas pipe 6, the branch flue gas pipe 7, and the flue gas nozzle 8, and finally blows along the deflector 9 at a relatively low flow rate, playing a role in preventing fly ash settlement.

[0067] It should be noted that during the ignition and operation of the boiler 100, the horizontal flue anti-ash accumulation device of the boiler always maintains a continuous operation state.

[0068] The basic logic of the automatic adjustment of the output of the furnace gas fan 2: At low loads, the flue gas volume is small, the flue gas flow rate is low, and fly ash is prone to settlement. At this time, the required flue gas volume for blowing should be increased; at high loads, the flue gas volume is large, the flue gas flow rate is high, and the fly ash settlement situation is alleviated. At this time, the required flue gas volume for blowing should be reduced. According to the above principles, the relationship between the frequency of the inverter of the furnace gas fan 2 and the coal input volume is given in Table 1. The control logic built in the DCS detects the value of the "total unit coal volume" in real time, and according to the broken line function, outputs the corresponding inverter control command in a timely manner, so as to realize the function of automatically adjusting the flue gas volume blown by the furnace gas fan 2.

[0069] Table 1 Relationship between unit coal volume and fan frequency

[0070]

[0071] It should be noted that the relationship between the fan inverter frequency and the coal input volume in Table 1 is not formulated based on experience, but is determined through actual cold-state tests. During the unit shutdown and maintenance period, when all safety measures are implemented in place, start the furnace gas fan 2, and use equipment such as a hot wire anemometer and an impeller anemometer to measure the flue gas flow rate at the outlet of the flue gas nozzle 8 and within its equidistant range. It is required that the flue gas flow rate should reach 3.5 m / s at the farthest position of the deflector 9 corresponding to the nozzle. When the flow rate does not reach, increase the frequency of the inverter of the furnace gas fan 2 until it meets the above requirements. The output of the furnace gas fan 2 under this working condition is the minimum fan frequency for playing the anti-ash accumulation role, and its corresponding frequency is for the 90 - 100% BRL working condition.

[0072] In the cold-state test, continue to increase the frequency of the inverter of the furnace gas fan 2, and conduct on-site measurements at the flue gas nozzle 8. When the flue gas flow rate at the farthest position of the deflector 9 reaches 10 m / s, the frequency at this time is the maximum frequency of the furnace gas fan 2, corresponding to the situation below the 30% BRL working condition of the unit. Between the 30% BRL - 90% BRL working conditions, the reasonable fan frequency can be given correspondingly between the maximum frequency and the minimum frequency by using the broken line function.

[0073] When the unit is shut down and the boiler horizontal flue anti - ash - accumulation device needs to be shut down synchronously, the boiler horizontal flue anti - ash - accumulation device is shut down according to the following steps:

[0074] 1. Click the "Stop" button of the furnace gas fan 2 on the DCS screen;

[0075] 2. The control module of the furnace gas fan 2 issues an instruction "set the frequency conversion instruction to 0", and simultaneously issues an instruction to close the inlet and outlet valves 141 of the fan. The judgment for the completion of this step is that the local frequency feedback of the frequency converter is 0 and the "fully closed" signals of the inlet valve 131 / outlet valve 141 are sent;

[0076] 3. Issue an instruction "open the breaker of the fan motor". The judgment for the completion of the step is that the "breaker opened" signal of the fan motor is sent;

[0077] 4. Issue an instruction "open the contactor of the frequency converter". The judgment for the completion of the step is that the "contactor opened" signal of the frequency converter is sent;

[0078] 5. The equipment is successfully shut down.

[0079] It should be noted that due to the relatively high operating temperature of the furnace gas fan 2, during the shutdown cooling process, the operation of "low - speed barring" must be carried out to avoid the problem of shaft bending. The basic principle of low - speed barring is to use the barring motor and the meshing device to re - drive the furnace gas fan 2 whose speed has dropped to a certain range, so as to maintain its stable speed until the shaft temperature drops to a safe value (for example, below 50 °C).

[0080] One or more embodiments of this specification are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of one or more embodiments of this specification shall be included within the protection scope of this application.

[0081] The above is only the specific implementation manner of this application, but the protection scope of this application is not limited thereto. Any person skilled in the art within the technical scope disclosed by this application can easily think of changes or substitutions, which should all be covered within the protection scope of this application. Therefore, the protection scope of this application shall be subject to the protection scope of the claims.

Claims

1. A boiler horizontal flue anti-ash accumulation device, characterized in that The device includes: a smoke extraction pipeline, a furnace flue gas fan, a dust separation component, an ash hopper, an ash discharge pipe, and a purging component; The smoke extraction pipeline is connected between the boiler tail gas flue and the purging component, and the smoke extraction pipeline is used to send the flue gas in the boiler tail gas flue to the purging component; The furnace flue gas fan is arranged in the smoke extraction pipeline, and the furnace flue gas fan is used to pump the flue gas; The dust separation component is arranged in the smoke extraction pipeline, and the dust separation component is used to separate the dust in the flue gas; The ash hopper is arranged in the smoke extraction pipeline, and the ash hopper is used to collect the separated dust; The ash discharge pipe is communicated with the ash hopper, and the ash discharge pipe is used to discharge the collected dust; The purging component is arranged at the bottom of the boiler horizontal flue, and the purging component is used to spray the flue gas to purge the ash accumulated in the boiler horizontal flue, and the jet speed of the purging component is 3 - 5 m / s.

2. The boiler horizontal flue ash accumulation prevention device according to claim 1, characterized in that, The smoke extraction pipeline is specifically connected between the outlet flue of the boiler denitration device and the purging component, and is used to send the flue gas in the outlet flue of the boiler denitration device to the purging component.

3. The boiler horizontal flue ash accumulation prevention device according to claim 1, characterized in that The smoke extraction pipeline includes a right-angle pipe section, and the right-angle pipe section is used to turn the flue gas to separate the dust in the flue gas.

4. The boiler horizontal flue ash accumulation prevention device according to claim 1, characterized in that, The smoke extraction pipeline includes a smoke extraction port, and the smoke extraction port extends into the boiler tail gas flue, and the orientation of the smoke extraction port is consistent with the flow direction of the flue gas in the boiler tail gas flue.

5. The boiler horizontal flue ash accumulation prevention device according to claim 1, characterized in that, The smoke extraction pipeline includes an inlet pipe section and an outlet pipe section. The inlet pipe section is connected to the inlet of the furnace flue gas fan and is provided with an inlet valve, and the outlet pipe section is connected to the outlet of the furnace flue gas fan and is provided with an outlet valve.

6. The boiler horizontal flue ash accumulation prevention device according to claim 5, characterized in that, Both the inlet valve and the outlet valve are provided with sealing air.

7. The boiler horizontal flue ash accumulation prevention device according to claim 1, characterized in that The number of the furnace flue gas fans is multiple, and the multiple furnace flue gas fans are arranged in parallel in the smoke extraction pipeline.

8. The boiler horizontal flue anti-ash accumulation device according to claim 1, characterized in that The purging component includes a flue gas access pipeline and a flue gas nozzle. The flue gas access pipeline is arranged in the boiler horizontal flue, and the flue gas nozzle is arranged on the flue gas access pipeline and is used to spray the flue gas.

9. The boiler horizontal flue ash accumulation prevention device according to claim 8, characterized in that, The purging component further includes a deflector, and the deflector is inclined at the bottom of the boiler horizontal flue and is used to deflect and upwardly drain the sprayed flue gas.

10. A method for a boiler horizontal flue ash accumulation prevention device, applicable to the boiler horizontal flue ash accumulation prevention device described in any one of claims 1-9, characterized in that, The method includes: the smoke extraction pipeline extracts the flue gas from the boiler tail gas flue. After the flue gas is separated from the dust by the dust separation component, it is sent to the purging component under the action of the furnace flue gas fan, and the purging component sprays the flue gas at a speed of 3 - 5 m / s to purge the ash accumulated in the boiler horizontal flue.

Images