A sootblowing device and sootblowing method for improving the blowing loss of boiler heat exchange surface

Abstract

The present invention discloses a device and a sootblowing method for improving the blowing damage of the heat exchange surface of a boiler, comprising a plurality of sootblowers, wherein the plurality of sootblowers are all connected to a gas pipeline, the end of the gas pipeline is fixedly connected to a sootblowing steam source, a gas pipeline shut-off valve and a pneumatic regulating valve are sealed and installed on the gas pipeline, the pressure port of the pneumatic regulating valve is connected to the outlet of a pressure transmitter, and the inlet of the pressure transmitter is connected to the gas pipeline. A pneumatic regulating valve is arranged on the gas pipeline of the present invention, and by arranging a pressure transmitter on the sootblowing pipeline, the pressure in the gas pipeline can be adjusted, and then the blowing pressure of the sootblower can be adjusted. The pressure reduction of the sootblower can greatly reduce the pressure of the condensed water on the sootblower directly impacting the heat exchange surface under the drive of the pressure gas, thereby solving the problem of pipe burst caused by blowing damage in the heat exchange surface.

Description

Technical Field

[0001] The invention relates to the field of thermal power generation, and in particular to a sootblowing device and a sootblowing method for improving the blowing loss of a boiler heat exchange surface. Background Art

[0002] In recent years, with the commissioning of a large number of high-parameter and large-capacity units, the cross-sectional dimensions of the boilers have become large, the sootblower stroke of the high-temperature heat exchange surface of the boilers has become longer, and the cooling flow has increased; coupled with the uncertainty of the boiler fuel used, the sootblowing of the boilers has been frequently commissioned; the high-temperature heat exchange surface of the boiler uses a fully retractable steam sootblower, and the gun barrel completely withdraws from the boiler flue when it is shut down.

[0003] Condensate will be generated in the gun barrel during the sootblower shutdown process. Due to the space limitation of the boiler and sootblower, effective measures cannot be taken to discharge it. Therefore, there will usually be steam with condensate at the initial stage of sootblower operation, which will cause a sharp increase in the erosion and thinning rate of the tube wall within a certain range after the start of the spraying point. The thinning rate is related to the sootblowing pressure. The higher the sootblowing pressure, the faster the thinning rate. The heat exchange surface space of high-parameter units is compact, the sootblower is close to the heat exchange surface, the pipe wall thickness margin is small, and the sootblower is close to the heat exchange surface, resulting in a high risk of erosion of the heat exchange surface. The erosion and thinning have a significant impact on the strength, and pipe burst accidents often occur. Summary of the invention

[0004] The main purpose of the present invention is to propose a sootblowing device and a sootblowing method for improving the blowing damage of the boiler heat exchange surface. By adjusting the pneumatic regulating valve on the sootblowing pipeline, the pressure of the sootblower sprayed from the nozzle is adjusted, thereby reducing the blowing damage to the heat exchange surface and avoiding the pipe burst accident due to the reduction of the wall thickness of the pipe on the heat exchange surface.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0006] A sootblowing device for improving the blowing damage of a boiler heat exchange surface comprises a plurality of sootblowers, wherein the plurality of sootblowers are all connected to a gas pipeline, the end of the gas pipeline is fixedly connected to a sootblowing steam source, a gas pipeline shut-off valve and a pneumatic regulating valve are sealed and installed on the gas pipeline, the pressure port of the pneumatic regulating valve is connected to the outlet of a pressure transmitter, and the inlet of the pressure transmitter is connected to the gas pipeline; the pressure transmitter is electrically connected to a DSC control device, and the DSC control device is electrically connected to the pressure port of the pneumatic regulating valve;

[0007] The sootblower comprises an outer sootblower tube, on the tube wall of which nozzles are symmetrically mounted, an inner sootblower tube and a sootblower shut-off valve are fixedly mounted inside the outer sootblower tube, and the sootblower shut-off valve is arranged between the gas pipeline and the inner sootblower tube.

[0008] A sootblowing method for improving the blowing damage of a boiler heat exchange surface, using a sootblowing device for improving the blowing damage of a boiler heat exchange surface, and the steps are as follows:

[0009] Step 1: The first soot blower moves forward in an empty stroke, the first soot blower shut-off valve is closed, the pressure transmitter on the gas pipeline outputs a first pressure P, and runs for a first running time T1;

[0010] Step 2: Open the shut-off valve on the first sootblower, pass steam, the pressure transmitter outputs the second pressure P1, and runs for the second running time T2;

[0011] Step 3: restore the output pressure of the first soot blower to the first pressure P, and maintain the first pressure P for the first soot blower to run forward for the third running time T3 until the forward end; maintain the first pressure P for the first soot blower to run backward for the fourth running time T4 until the soot blowing is completed, close the shut-off valve on the first soot blower, and cut off the soot blower steam;

[0012] Step 4: The idle stroke of the first soot blower returns to the fifth operation time T5, at which time the shut-off valve of the first soot blower is closed, and the pressure transmitter on the gas pipeline outputs the first pressure P;

[0013] Step 5: The second soot blower moves forward in an idle stroke, the shut-off valve of the second soot blower is closed, the pressure transmitter on the gas pipeline outputs the first pressure P, and runs for the first running time T1;

[0014] Step 6: Open the shut-off valve on the second sootblower, the pressure transmitter outputs the second pressure P1, and runs for the second running time T2;

[0015] Step 7: restore the output pressure of the second sootblower to the first pressure P, and maintain the first pressure P for the second sootblower to run forward for the third running time T3 until the forward end; maintain the first pressure P for the second sootblower to run backward for the fourth running time T4 until the sootblowing is completed, close the shut-off valve on the second sootblower, and cut off the sootblower steam;

[0016] Step 8: The idle stroke of the second sootblower returns to the fifth operation time T5, at which time the shut-off valve of the second sootblower is closed, and the pressure transmitter on the gas pipeline outputs the first pressure P;

[0017] Step 9: According to Step 5 and Step 8, adjust the shut-off valves of the remaining sootblowers and the delivery pressure of the pressure transmitter in sequence.

[0018] Preferably, the first soot blower moves forward in an idle stroke, and the nozzle on the outer tube of the soot blower gradually enters the flue wall; when the soot blower shut-off valve is opened, the nozzle on the outer tube of the soot blower has reached the inner side of the flue.

[0019] Preferably, the first pressure P is greater than the second pressure P1.

[0020] Preferably, the pressure transmitter outputs at least two pressure levels.

[0021] The present invention provides a sootblowing device and a sootblowing method for improving the blowing damage of a boiler heat exchange surface, which have the following beneficial effects: a pneumatic regulating valve is arranged on a gas pipeline, and by arranging a pressure transmitter on the sootblowing pipeline, the pressure in the gas pipeline can be adjusted, and then the blowing pressure of the sootblower can be adjusted. The pressure reduction of the sootblower can greatly reduce the pressure of condensed water on the sootblower directly impacting the pipes on the heat exchange surface driven by the pressurized gas, thereby solving the problem of pipe blowing damage and bursting in the heat exchange surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below.

[0023] Figure 1 It is a schematic diagram of the working principle of the gas pipeline of the present invention;

[0024] Figure 2 It is a schematic diagram of the shutdown state of the soot blower of the present invention;

[0025] Figure 3 It is a schematic diagram of the working state of the soot blower of the present invention;

[0026] Figure 4 It is a schematic diagram of the soot blowing pressure of the first soot blower;

[0027] In the figure: 1. Sootblower; 101. Sootblower outer tube; 102. Sootblower inner tube; 103. Nozzle; 104. Sootblower shut-off valve; 105. First sootblower; 106. Second sootblower; 2. Gas pipeline; 3. Sootblowing steam source; 4. Gas pipeline shut-off valve; 5. Pneumatic regulating valve; 6. Pressure transmitter; 7. DSC control device. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the present invention.

[0029] Embodiment 1, as Figure 1 As shown, a sootblowing device for improving the blowing loss of boiler heat exchange surface includes a plurality of sootblowers 1, which are all connected to a gas pipeline 2, the end of the gas pipeline 2 is fixedly connected to a sootblowing steam source 3, a gas pipeline shut-off valve 4 and a pneumatic regulating valve 5 are sealed and installed on the gas pipeline 2, the pressure port of the pneumatic regulating valve 5 is connected to the outlet of the pressure transmitter 6, and the inlet of the pressure transmitter 6 is connected to the gas pipeline 2.

[0030] Working principle: The force of the pressurized gas from the sootblowing steam source 3 blowing onto the heat exchange tube at the heat exchange surface is related to the size of the nozzle 103 on the sootblower 1 and the pressure before the nozzle 103, and the pressure before the nozzle 103 is controlled by the pneumatic regulating valve 5 on the gas pipeline 2. The steam from the sootblowing steam source first passes through the gas pipeline shut-off valve 4 and then enters the pneumatic regulating valve 5. The pneumatic regulating valve 5 adjusts the pressure downstream to a preset pressure according to the signal of the pressure transmitter 6 downstream thereof. The higher the set adjustment pressure, the higher the sootblowing pressure before the nozzle 103 on the sootblower, and the lower the set adjustment pressure, the lower the sootblowing pressure before the nozzle 103 on the sootblower. The present invention adopts two-stage or multi-stage pressure setting during sootblowing, which effectively improves the blowing damage problem caused by the original sootblower having a single set pressure during operation.

[0031] A pneumatic regulating valve 5 and a gas pipeline shut-off valve 4 are provided on the gas pipeline 2 to block or connect the gas pipeline 2. By providing a pressure transmitter 6 on the sootblowing pipeline, the pressure in the gas pipeline 2 can be adjusted, and then the blowing pressure of the sootblower 1 can be adjusted. The pressure reduction of the sootblower 1 can prevent the condensed water on the sootblower 1 from directly impacting the pipes on the heat exchange surface under the drive of the pressurized gas, thereby solving the pipe burst problem in the heat exchange surface.

[0032] In this embodiment, the pressure transmitter 6 is electrically connected to the DSC control device 7, and the DSC control device 7 is electrically connected to the pressure port of the pneumatic control valve 5. By setting the DSC control device 7 to adjust the opening degree of the pneumatic control valve 5, it is convenient to remotely control the gas pressure in the soot blower 1, which is convenient for the automatic control of the entire device.

[0033] Embodiment 2, as Figures 2 to 3 As shown, this embodiment is a preferred technical solution of the first embodiment, the sootblower 1 comprises a sootblower outer tube 101, on the tube wall of the sootblower outer tube 101, nozzles 103 are symmetrically installed, the sootblower is fixedly installed with a sootblower inner tube 102 and a sootblower shut-off valve 104, and the sootblower shut-off valve 104 is arranged between the gas pipeline 2 and the sootblower inner tube 102. After the pressurized gas in the gas pipeline 2 flows from the sootblower shut-off valve 104 to the sootblower inner tube 102, it is blown out by the nozzle 103 on the sootblower outer tube 101 and flows to the tubes on the heat exchange surface for sootblowing treatment.

[0034] A soot blowing method using a soot blowing device for improving the blowing loss of a boiler heat exchange surface, the steps of which are:

[0035] Step 1: The first soot blower moves forward in an empty stroke, the first soot blower shut-off valve is closed, the pressure transmitter on the gas pipeline outputs a first pressure P, and runs for a first running time T1;

[0036] Step 2: Open the shut-off valve on the first sootblower, pass steam, the pressure transmitter outputs the second pressure P1, and runs for the second running time T2;

[0037] Step 3: restore the output pressure of the first soot blower to the first pressure P, and maintain the first pressure P for the first soot blower to run forward for the third running time T3 until the forward end; maintain the first pressure P for the first soot blower to run backward for the fourth running time T4 until the soot blowing is completed, close the shut-off valve on the first soot blower, and cut off the soot blower steam;

[0038] Step 4: The idle stroke of the first soot blower returns to the fifth operation time T5, at which time the shut-off valve of the first soot blower is closed, and the pressure transmitter on the gas pipeline outputs the first pressure P;

[0039] Step 5: The second soot blower moves forward in an idle stroke, the shut-off valve of the second soot blower is closed, the pressure transmitter on the gas pipeline outputs the first pressure P, and runs for the first running time T1;

[0040] Step 6: Open the shut-off valve on the second sootblower, the pressure transmitter outputs the second pressure P1, and runs for the second running time T2;

[0041] Step 7: restore the output pressure of the second sootblower to the first pressure P, and maintain the first pressure P for the second sootblower to run forward for the third running time T3 until the forward end; maintain the first pressure P for the second sootblower to run backward for the fourth running time T4 until the sootblowing is completed, close the shut-off valve on the second sootblower, and cut off the sootblower steam;

[0042] Step 8: The idle stroke of the second sootblower returns to the fifth operation time T5, at which time the shut-off valve of the second sootblower is closed, and the pressure transmitter on the gas pipeline outputs the first pressure P;

[0043] Step 9: According to Step 5 and Step 8, adjust the shut-off valves of the remaining sootblowers and the delivery pressure of the pressure transmitter in sequence.

[0044] like Figures 1 to 4As shown, the working process is as follows: the first soot blower 105 receives a start instruction, i.e., the soot blowing start point A in the figure, the soot blower moves forward under the first pressure P to prepare to enter the flue wall, during the T1 time period, the shut-off valve 104 of the soot blower of the first soot blower 105 is in a closed state, the gas pipeline 2 is filled with pressurized gas, and the pressurized gas does not flow at this time, and after reaching the blowing start point C, the soot blower has moved forward to enter the flue wall, the soot blower shut-off valve 104 of the first soot blower 105 is opened, and the pressure of the pressure transmitter 6 is set to the second pressure P1, i.e., the blowing start point D in the figure, and the pressurized gas in the gas pipeline 2 flows out of the soot blower, and the second pressure P1 is the minimum cooling pressure of this section; at this time, the condensed water in the soot blower outer tube 101 is blown out with the steam under the action of the second pressure P1, even if some exists, the soot blowing pressure received by the heat exchange surface is large The pressure transmitter outputs the second pressure P1 for T2 time, and then the first soot blower 105 advances to point E. At this time, the condensed water in the soot blower 1 has been drained out, and the pressure is restored to the first pressure P and the soot blower advances for T3 time to reach the forward end point. At this time, when the soot blower 1 cleans the heat exchange surface, the pressure increases and the condensed water is no longer blown out, and the heat exchange surface tube is not damaged. At this time, the first soot blower 105 maintains the first pressure P and runs backward for T4 time until it reaches the stop point Q, and the cleaning is completed. At this time, the soot blower shut-off valve 104 of the first soot blower 105 is closed, and the soot blower no longer blows gas to the heat exchange surface. The pressure of the pressure transmitter 6 maintains the first pressure P. The first soot blower 105 continues to run backward for T5 time to the stop point B, and the second soot blower 106 waits for the start instruction.

[0045] After the second soot blower 106 and the remaining soot blowers receive the start-up instruction in sequence, they repeat the operation process of the first soot blower 105 in sequence.

[0046] Under the prior art, as shown in the figure, line segment ACFB and line segment MNZQ, where line segment ACFB is a schematic line of sootblowing pressure at normal pressure (first pressure P), and line segment MNZQ is the maximum purge pressure blown onto the heat exchange surface. During the T2 time period, that is, after the nozzle on the outer tube of the sootblower enters the flue, the heat exchange surface tubes are damaged in the MN section due to the action of the purge pressure on the condensed water.

[0047] After adopting the new method, the line segment ACFB is improved to the line segment ACDEF, and its corresponding pressure is adjusted to the joint action of the first pressure P and the second pressure P1. The line segment MNZQ is replaced by the curve segment XYZQ. When the second pressure P1 acts, the corresponding surface pressure of the heat exchange surface is lower than the pressure when the first pressure P acts on the heat exchange surface alone; that is, in the time period T2, the first pressure P1 blown out by the soot blowing pressure of the pressure transmitter 6 is reduced to the second pressure P1, and the soot blowing pressure received by the heat exchange surface is greatly reduced. At this time, even if there is condensed water, the heat exchange surface will not be damaged by the second pressure P1.

[0048] Among them, the pressure transmitter 6 outputs at least two pressure levels. The pressure transmitter 6 sets the initial low pressure according to the action time of the soot blower. For example, in the prior art, the soot blower full stroke interval soot blower pressure reducing station has only one set pressure of 2.5MPa. The present application is to set two or more pressure levels, for example, the initial pressure of the soot blower is set to 1.5MPa, and the subsequent setting is 2.5MPa. The present application is not limited to two pressure levels, such as setting the incremental pressure of 1.0 / 1.5 / 2.5MPa in different time periods. The number of levels, the time of each level and the pressure of each level can be set according to the specific conditions of each project.

[0049] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; the pattern fillings in the drawings of the present invention do not represent the materials of the structures, but only distinguish the structures; in the description of the present invention, it should be noted that the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance. Although the present invention has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some of the technical features therein can be replaced by equivalents; and these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A sootblowing method for improving the blowing damage of boiler heat exchange surface, using a sootblowing device for improving the blowing damage of boiler heat exchange surface, characterized in that: The sootblowing device comprises a plurality of sootblowers, all of which are connected to a gas pipeline, the end of the gas pipeline is fixedly connected to a sootblowing steam source, a gas pipeline shut-off valve and a pneumatic regulating valve are sealed and installed on the gas pipeline, the pressure port of the pneumatic regulating valve is connected to the outlet of the pressure transmitter, and the inlet of the pressure transmitter is connected to the gas pipeline; the pressure transmitter is electrically connected to the DSC control device, and the DSC control device is electrically connected to the pressure port of the pneumatic regulating valve; The sootblower comprises a sootblower outer tube, on the tube wall of which nozzles are symmetrically mounted, and inside the sootblower outer tube a sootblower inner tube and a sootblower shut-off valve are fixedly mounted, wherein the sootblower shut-off valve is arranged between the gas pipeline and the sootblower inner tube; The steps of the soot blowing method are: Step 1: The first soot blower moves forward in an empty stroke, the first soot blower shut-off valve is closed, the pressure transmitter on the gas pipeline outputs a first pressure P, and runs for a first running time T1; Step 2: Open the shut-off valve on the first sootblower, pass steam, the pressure transmitter outputs the second pressure P1, and runs for the second running time T2; Step 3: restore the output pressure of the first soot blower to the first pressure P, and maintain the first pressure P while the first soot blower runs forward for the third running time T3 to the forward end point; The first soot blower is operated backward for a fourth operation time T4 while maintaining the first pressure P until the soot blowing is completed, and the shut-off valve on the first soot blower is closed to cut off the soot blower steam; Step 4: The idle stroke of the first soot blower returns to the fifth operation time T5, at which time the shut-off valve of the first soot blower is closed, and the pressure transmitter on the gas pipeline outputs the first pressure P; Step 5: The second soot blower moves forward in an idle stroke, the shut-off valve of the second soot blower is closed, the pressure transmitter on the gas pipeline outputs the first pressure P, and runs for the first running time T1; Step 6: Open the shut-off valve on the second sootblower, the pressure transmitter outputs the second pressure P1, and runs for the second running time T2; Step 7: restore the output pressure of the second soot blower to the first pressure P, and maintain the first pressure P. The second soot blower runs forward for the third running time T3 to the forward end point; The second sootblower is operated backward for a fourth operation time T4 while maintaining the first pressure P until the sootblowing is finished, and the shut-off valve on the second sootblower is closed to cut off the sootblower steam; Step 8: The idle stroke of the second sootblower returns to the fifth operation time T5, at which time the shut-off valve of the second sootblower is closed, and the pressure transmitter on the gas pipeline outputs the first pressure P; Step 9: According to Step 5 and Step 8, adjust the shut-off valve of the remaining soot blower and the delivery pressure of the pressure transmitter in sequence; The first pressure P is greater than the second pressure P1.

2. A sootblowing method for improving the blowing loss of boiler heat exchange surface according to claim 1, characterized in that: The first soot blower moves forward in an idle stroke, and the nozzle on the outer tube of the soot blower gradually enters the flue wall; when the soot blower shut-off valve is opened, the nozzle on the outer tube of the soot blower has reached the inner side of the flue.

3. A sootblowing method for improving the blowing loss of boiler heat exchange surface according to claim 1, characterized in that: The pressure transmitter outputs at least two levels of pressure.

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