Cooling air automatic control method of air-cooled dry slag extractor

Abstract

The embodiment of the invention provides an automatic cooling air control method for an air-cooled dry slag extractor, which comprises the following steps of: performing an opening degree quantitative test on a side cooling air door and a head cooling air door of the air-cooled dry slag extractor; the target fixed opening degree of the side cooling air door and the corresponding preset opening degrees of the head cooling air door under different loads are obtained; a temperature measuring device is arranged at a climbing section of the air-cooled dry slag extractor; and the side cooling air door is kept at the target fixed opening degree, and when the temperature measuring device detects that the slag temperature of the climbing section of the air-cooled dry slag extractor exceeds a slag temperature threshold value, the opening degree of the head cooling air door is controlled to be increased by a first target opening degree on the basis of the preset opening degree. According to the cooling air automatic control method disclosed by the embodiment of the invention, the side cooling air door can be optimally arranged, the opening degree of the head cooling air door is further controlled in combination with the temperature measuring device, and high-temperature slag is effectively cooled.

Description

Technical Field

[0001] The embodiments of the present disclosure belong to the technical field of air-cooled dry slag dischargers, and particularly relate to a cooling air automatic control method for an air-cooled dry slag discharger. Background Art

[0002] The air-cooled dry slag discharge system of coal-fired boilers generally sets the slag discharge temperature monitoring device at the entrance of the head slag bin. When the high-temperature slag moves to the head and is about to fall into the slag bin, the slag discharge temperature monitoring device will show that the slag discharge temperature has increased. At this time, it is too late for the electric cooling damper of the head to operate. Not only can it not effectively cool the high-temperature slag, but it also increases the air leakage at the bottom of the furnace, causing the boiler exhaust temperature to increase and the exhaust heat loss to increase. In addition, the current slag falling monitoring of dry slag dischargers mostly remains in the state of manual monitoring by cameras. When large slag falls from the furnace or the amount of slag increases suddenly, the operating personnel often fail to discover it in time, causing the slag discharge temperature to rise rapidly to more than 200°C, which seriously harms the normal operation of the dry slag discharger. Summary of the invention

[0003] The embodiments of the present disclosure aim to solve at least one of the technical problems existing in the prior art and provide a cooling air automatic control method for an air-cooled dry slag discharger.

[0004] An embodiment of the present disclosure provides a cooling air automatic control method for an air-cooled dry slag discharger, the cooling air automatic control method comprising:

[0005] Conducting quantitative opening tests on the side cooling air door and the head cooling air door of the air-cooled dry slag discharger to obtain the target fixed opening of the side cooling air door and the preset opening of the head cooling air door corresponding to different loads;

[0006] A temperature measuring device is provided at the climbing section of the air-cooled dry slag discharger;

[0007] The side cooling air door is maintained at the target fixed opening. When the temperature measuring device detects that the slag temperature in the climbing section of the air-cooled dry slag discharger exceeds the slag temperature threshold, the opening of the head cooling air door is controlled to increase to a first target opening based on the preset opening.

[0008] Optionally, the cooling air automatic control method further includes:

[0009] A slag quantity monitoring device is arranged at the climbing section of the air-cooled dry slag discharger;

[0010] When the slag amount monitoring device detects that the slag amount in the climbing section of the air-cooled dry slag discharger exceeds a slag amount threshold, the opening of the head cooling air door is controlled to increase a second target opening on the basis of the preset opening.

[0011] Optionally, the temperature measuring device is a non-contact acoustic temperature measuring device, and the slag quantity monitoring device is a line laser binocular stereo camera.

[0012] Optionally, the quantitative opening test of the side cooling air door and the head cooling air door of the air-cooled dry slag discharger is performed to obtain the target fixed opening of the side cooling air door and the preset opening of the head cooling air door corresponding to different loads, including:

[0013] Under typical working conditions, the fixed openings of the side cooling air doors at the bottom of the slag pit and at both sides of the climbing section of the air-cooled dry slag discharger are adjusted one by one to obtain the fixed opening of the side cooling air door when the air-cooled dry slag discharger requires the least cooling air, and the fixed opening is the target fixed opening;

[0014] The side cooling air door is maintained at the target fixed opening, and the opening corresponding to the head cooling air door under different loads is tested, and the opening is the preset opening.

[0015] Optionally, the openings of the head cooling damper under different loads in the test include:

[0016] Under different loads, the slag discharge temperature of the air-cooled dry slag discharger is monitored by a bin entry temperature monitor located at the head cooling air door;

[0017] The opening of the head cooling air door is PID-controlled according to the temperature monitored by the inlet temperature monitor, so that the slag discharge temperature of the air-cooled dry slag discharger is kept below a safety threshold.

[0018] Optionally, the opening of the head cooling air door is PID-controlled according to the temperature monitored by the entry temperature monitor, including:

[0019] The temperature monitored by the inlet temperature monitor is compared with the set value of the slag discharge temperature, and the opening of the head cooling air door is controlled by PID so that the temperature monitored by the inlet temperature monitor is less than the set value of the slag discharge temperature; wherein,

[0020] The set value of the slag discharge temperature is less than the safety threshold.

[0021] Optionally, before conducting the quantitative opening test, the cooling capacity of the side cooling damper and the head cooling damper of the air-cooled dry slag discharger is obtained by numerically simulating the internal flow field of the air-cooled dry slag discharger.

[0022] The automatic cooling air control method of the air-cooled dry slag discharger of the embodiment of the present disclosure can optimize the setting of the side cooling air doors, and further control the opening of the head cooling air doors in combination with the temperature measuring device, which can effectively cool the high-temperature slag, reduce air leakage at the bottom of the furnace and heat loss from exhaust gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of an air-cooled dry slag discharger according to an embodiment of the present disclosure;

[0024] Figure 2 This is a schematic flow chart of a cooling air automatic control method for an air-cooled dry slag discharger according to an embodiment of the present disclosure;

[0025] Figure 3 A three-dimensional modeling diagram of an air-cooled dry slag discharger according to another embodiment of the present disclosure;

[0026] Figure 4 This is a cloud diagram of the internal flow field distribution in the middle section of an air-cooled dry slag discharger according to another embodiment of the present disclosure;

[0027] Figure 5 A cloud diagram of the internal flow field distribution of a cross section of an air-cooled dry slag discharger according to another embodiment of the present disclosure;

[0028] Figure 6 This is a slag amount monitoring curve of an air-cooled dry slag discharger according to another embodiment of the present disclosure. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the technical solution of the present disclosure, the present disclosure is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0030] like Figure 1 As shown, the present disclosure is explained by taking the air-cooled dry slag discharger of a 660MW ultra-supercritical coal-fired unit as an example. A slag well is provided above the tail of the air-cooled dry slag discharger, through which the high-temperature slag from the boiler can be received and discharged onto the transmission steel belt of the air-cooled dry slag discharger. The high-temperature slag discharged onto the transmission steel belt passes through the tail and climbing section of the air-cooled dry slag discharger in turn, and finally falls into the slag bin at the head position. Corresponding side cooling dampers are provided on both sides of the tail and climbing section of the air-cooled dry slag discharger, and a head cooling damper and a bin temperature monitor are also provided at the head position of the air-cooled dry slag discharger.

[0031] like Figure 2 As shown, a cooling air automatic control method for an air-cooled dry slag discharger is provided. The cooling air automatic control method first obtains the cooling capacity of the side cooling air door and the head cooling air door of the air-cooled dry slag discharger by numerically simulating the internal flow field of the air-cooled dry slag discharger.

[0032] Specifically, in this step, refer to Figures 3 to 5 The internal flow field of the air-cooled dry slag discharger can be simulated by computer numerical simulation to establish a Figure 3The three-dimensional model of the air-cooled dry slag discharger shown in FIG. Figure 4 and Figure 5 The flow field distribution cloud diagram of the cross section and cross section of the air-cooled dry slag discharger is shown.

[0033] Analysis shows that there is a certain cooling air flow dead zone below the slag pit 1 at the edge of the rear of the air-cooled dry slag discharger. Therefore, the opening of the first pair of side cooling air doors (side cooling air door 1) should not be fully closed to ensure that a certain amount of cooling air flows through this area. In addition, the cooling air penetration ability of the side cooling air doors near the bottom of the slag pit 1 is strong (side cooling air doors 1 to 4). When the side cooling air doors in this area are fully opened, the cooling air speed is too high, which to a certain extent offsets the air flow disturbance of the two cooling airs, reducing the convective heat exchange effect. It is advisable to appropriately close the air door in this area (maintain a symmetrical opening mode) to reduce the cooling air consumption of the air-cooled dry slag discharger.

[0034] S110, conducting a quantitative opening test on the side cooling air door and the head cooling air door of the air-cooled dry slag discharger to obtain a target fixed opening of the side cooling air door and a preset opening corresponding to the head cooling air door under different loads.

[0035] Specifically, in this step, the fixed openings of the side cooling dampers at the bottom of the slag pit and on both sides of the climbing section of the air-cooled dry slag discharger are adjusted one by one under typical working conditions to obtain the fixed opening of the side cooling dampers when the air-cooled dry slag discharger requires the least cooling air, and the fixed opening is the target fixed opening. The side cooling dampers are kept at the target fixed opening, and the openings corresponding to the head cooling dampers under different loads are tested, and the openings are the preset openings. The goal is to keep the openings of the side cooling dampers of the air-cooled dry slag discharger at the target fixed openings unchanged under different loads, and adjust the cooling air volume of the dry slag discharger through the head cooling dampers to control the slag discharge temperature.

[0036] For the side cooling dampers, their damper opening should not be fixed in the fully open position. The side cooling dampers in the climbing section should be appropriately closed or opened at intervals. The head cooling dampers should be kept at a certain opening to play their regulatory role under different working conditions. Otherwise, the head cooling dampers may remain in the fully closed state for a long time under high, medium and low load conditions of the unit. It is recommended that the head cooling damper opening be kept at about 60% under full load conditions of the unit.

[0037] The following table shows the recommended target fixed openings for the cooling air doors on each side obtained from the test.

[0038]

[0039] Among them, the opening corresponding to the head cooling air door under different loads in the test includes: under different loads, the slag discharge temperature of the air-cooled dry slag discharger is monitored by the inlet temperature monitor located at the head cooling air door. The opening of the head cooling air door is PID controlled according to the temperature monitored by the inlet temperature monitor, so that the slag discharge temperature of the air-cooled dry slag discharger is kept below the safety threshold. Air-cooled dry slag dischargers all need to monitor the inlet temperature at the slag bin entrance, and automatically control the opening of the head cooling air door of the dry slag discharger based on the real-time measurement value of the inlet temperature.

[0040] Further, the opening of the head cooling air door is PID-controlled according to the temperature monitored by the silo temperature monitor, including: comparing the temperature monitored by the silo temperature monitor with the set value of the slag discharge temperature, and controlling the opening of the head cooling air door through PID so that the temperature monitored by the silo temperature monitor is less than the set value of the slag discharge temperature. The set value of the slag discharge temperature is less than the safety threshold, leaving a margin.

[0041] S120, providing a temperature measuring device at the climbing section of the air-cooled dry slag discharger.

[0042] Specifically, refer to Figure 1 A temperature measuring device is installed in the climbing section of the air-cooled dry slag discharger. The temperature measuring device can be set as a non-contact acoustic temperature measurement to avoid contact with high-temperature slag and collision. Since all high-temperature slag received by the slag pit will pass through the climbing section, a temperature measuring device is installed at the starting end of the climbing section to obtain the slag temperature signal in time without missing the high-temperature slag, thus realizing real-time monitoring of the slag temperature in the climbing section.

[0043] S130, maintaining the side cooling air door at the target fixed opening, when the temperature measuring device detects that the slag temperature in the climbing section of the air-cooled dry slag discharger exceeds the slag temperature threshold, controlling the opening of the head cooling air door to increase the first target opening on the basis of the preset opening.

[0044] Specifically, in this step, when the temperature measuring device detects a high temperature signal in real time, it is linked with the head cooling air door, and the head cooling air door is automatically opened to the first target opening. That is, when the temperature measuring device detects that the slag temperature in the climbing section exceeds the slag temperature threshold, the opening of the head cooling air door is linked to increase the first target opening on the basis of the preset opening. The head cooling air door is set as a head electric cooling air door.

[0045] Further, refer to Figure 1The cooling air automatic control method further includes: providing a slag amount monitoring device in the climbing section of the air-cooled dry slag discharger. When the slag amount monitoring device detects that the slag amount in the climbing section of the air-cooled dry slag discharger exceeds a slag amount threshold, controlling the opening of the head cooling air door to increase a second target opening on the basis of the preset opening.

[0046] Specifically, in this step, when the slag amount monitoring device detects that the slag amount in the climbing section exceeds the slag amount threshold, it is linked with the head cooling air door, and the head cooling air door is immediately automatically opened to the second target opening. That is, when the slag amount monitoring device detects that the slag amount in the climbing section exceeds the slag amount threshold, the opening of the head cooling air door is linked to increase the second target opening on the basis of the preset opening.

[0047] Combination Figure 6 The slag quantity monitoring device can be set as a line laser binocular stereo camera, which can calculate the stacked continuous high-temperature slag on the dynamic transmission steel belt and perform real-time mass flow statistics through the line laser binocular stereo camera, so as to realize the real-time monitoring of the slag discharge amount of the dry slag discharger. Based on the online monitoring of the slag quantity in the climbing section, the slag falling in the slag pit will be captured by the slag quantity monitoring device in the climbing section, and the information will be linked with the cooling air door of the head of the dry slag discharger, especially it can automatically adapt to the soot blowing condition of the boiler furnace, so as to avoid the operator failing to manually open the head cooling air door in advance, or blindly opening the head cooling air door, so as to ensure the safe operation of the dry slag discharger and take into account the economic operation.

[0048] The cooling air automatic control method of the air-cooled dry slag discharger of the embodiment of the present disclosure obtains the optimal setting of the side cooling air door through numerical simulation and quantitative opening test, and realizes the real-time automatic control of the head cooling air door of the air-cooled dry slag discharger during hot operation in combination with the online monitoring of the slag amount and slag temperature, taking into account the safe and economical operation of the dry slag discharger in hot state. It can effectively cool the high-temperature slag, reduce the air leakage at the bottom of the furnace and the heat loss of smoke exhaust, and can timely monitor the high-temperature slag and link the head cooling air door action.

[0049] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present disclosure, but the present disclosure is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and substance of the present disclosure, and these modifications and improvements are also considered to be within the scope of protection of the present disclosure.

Claims

1. A cooling air automatic control method for an air-cooled dry slag discharger, characterized in that: The cooling air automatic control method comprises: Conducting quantitative opening tests on the side cooling air door and the head cooling air door of the air-cooled dry slag discharger to obtain the target fixed opening of the side cooling air door and the preset opening of the head cooling air door corresponding to different loads; A temperature measuring device is provided at the climbing section of the air-cooled dry slag discharger; The side cooling air door is maintained at the target fixed opening. When the temperature measuring device detects that the slag temperature in the climbing section of the air-cooled dry slag discharger exceeds the slag temperature threshold, the opening of the head cooling air door is controlled to increase to a first target opening based on the preset opening.

2. The cooling air automatic control method of the air-cooled dry slag discharger according to claim 1, characterized in that: The cooling air automatic control method further comprises: A slag quantity monitoring device is arranged at the climbing section of the air-cooled dry slag discharger; When the slag amount monitoring device detects that the slag amount in the climbing section of the air-cooled dry slag discharger exceeds a slag amount threshold, the opening of the head cooling air door is controlled to increase a second target opening on the basis of the preset opening.

3. The cooling air automatic control method of the air-cooled dry slag discharger according to claim 2, characterized in that: The temperature measuring device is a non-contact acoustic temperature measuring device, and the slag quantity monitoring device is a line laser binocular stereo camera.

4. The cooling air automatic control method of the air-cooled dry slag discharger according to any one of claims 1 to 3, characterized in that: The quantitative opening test of the side cooling air door and the head cooling air door of the air-cooled dry slag discharger is performed to obtain the target fixed opening of the side cooling air door and the preset opening of the head cooling air door corresponding to different loads, including: Under typical working conditions, the fixed openings of the side cooling air doors at the bottom of the slag pit and at both sides of the climbing section of the air-cooled dry slag discharger are adjusted one by one to obtain the fixed opening of the side cooling air door when the air-cooled dry slag discharger requires the least cooling air, and the fixed opening is the target fixed opening; The side cooling air door is maintained at the target fixed opening, and the opening corresponding to the head cooling air door under different loads is tested, and the opening is the preset opening.

5. The cooling air automatic control method of the air-cooled dry slag discharger according to claim 4, characterized in that: The openings of the head cooling damper under different loads in the test include: Under different loads, the slag discharge temperature of the air-cooled dry slag discharger is monitored by a bin entry temperature monitor located at the head cooling air door; The opening of the head cooling air door is PID-controlled according to the temperature monitored by the inlet temperature monitor, so that the slag discharge temperature of the air-cooled dry slag discharger is kept below a safety threshold.

6. The cooling air automatic control method of the air-cooled dry slag discharger according to claim 5, characterized in that: The opening of the head cooling air door is PID-controlled according to the temperature monitored by the entry temperature monitor, including: The temperature monitored by the inlet temperature monitor is compared with the set value of the slag discharge temperature, and the opening of the head cooling air door is controlled by PID so that the temperature monitored by the inlet temperature monitor is less than the set value of the slag discharge temperature; wherein, The set value of the slag discharge temperature is less than the safety threshold.

7. The cooling air automatic control method of an air-cooled dry slag discharger according to any one of claims 1 to 3, characterized in that: Before conducting the quantitative opening test, the cooling capacities of the side cooling dampers and the head cooling dampers of the air-cooled dry slag discharger are obtained by numerically simulating the internal flow field of the air-cooled dry slag discharger.

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