A boiler water wall dust pollution monitoring system

Abstract

The present invention provides a boiler water wall soot pollution monitoring system, wherein the boiler water wall has N soot blowers, N≥1, the N soot blowers are located at M different heights, M≥1, each height has n soot blowers, 1≤n≤N, and the monitoring system comprises J fin thermocouples, K tube wall thermocouples, a temperature data collector, and a data processing platform. The present invention arranges fin thermocouples near each soot blower. On the one hand, the number of fin thermocouples required is small. On the other hand, once the water wall area where the thermocouple is located is detected to have a high pollution rate, the soot blowing operation can be performed by controlling the soot blowers near the thermocouple to keep the heating surface clean and monitor the soot blowing effect.

Description

Technical Field

[0001] The invention relates to the technical field of intelligent control systems for combustion equipment, and in particular to a boiler water-cooled wall dust pollution monitoring system. Background Art

[0002] Boilers are key equipment for power station operation. During operation, coal-fired boilers will produce a large amount of ash, a byproduct of coal combustion in the furnace, which will inevitably cause varying degrees of ash contamination on the heating surface. Sootblowing is an effective means to remove ash contamination and keep the boiler heating surface clean. The sootblower uses a certain sootblowing medium (water, steam, sound waves, etc.) to blow the heating surface to remove surface dirt and restore its surface to a clean state. The sootblowing system is an important means to improve the unit availability and ensure the safe and economical operation of the unit.

[0003] At present, the sootblowing operation of large-scale power station boilers generally adopts a timed and quantitative program control method. This method is carried out without understanding the actual soot pollution state of the heating surface, which will inevitably lead to insufficient or excessive sootblowing. In addition, the sootblowing time and location are mostly determined by experience, which is subjective. In addition, if the sootblowing cycle is too short, it will lead to unnecessary sootblowing fluid consumption, reduce the service life of the heating surface and the service life of the sootblower itself, and increase additional cost expenses; if the sootblowing cycle is too long, the soot layer will be too thick and difficult to clean, resulting in poor sootblowing effect. Therefore, it is particularly important to monitor the soot pollution of the boiler water-cooled wall in real time, and then reasonably put the sootblowing system into use to obtain better economic benefits for the boiler. Summary of the invention

[0004] The technical problem to be solved by the present invention is that the soot blowing system is prone to insufficient soot blowing, excessive soot blowing and improper soot blowing cycle during operation.

[0005] In order to solve the above technical problems, the technical solution of the present invention is to provide a boiler water-cooled wall soot pollution monitoring system, wherein there are N soot blowers on the boiler water-cooled wall, N≥1, the N soot blowers are located at M different heights, M≥1, each height has n soot blowers, 1≤n≤N, characterized in that the monitoring system includes J fin thermocouples, K tube wall thermocouples, a temperature data collector, and a data processing platform, 1≤J≤N, 1≤K≤J;

[0006] J fin thermocouples are arranged near J sootblowers respectively, the jth fin thermocouple is arranged at the water-cooled wall fin of the boiler water-cooled wall within a certain distance D from the jth sootblowers, j=1,…,J, and the fin temperature of the water-cooled wall fin is measured by the fin thermocouple;

[0007] K tube wall thermocouples are respectively arranged at the outermost part of the back-fire side of the water-cooled wall tube of the boiler water-cooled wall adjacent to the K fin thermocouples, and are used to measure the tube wall temperature of the water-cooled wall tube;

[0008] The fin temperature measured by the fin thermocouple and the tube wall temperature measured by the tube wall thermocouple are connected to the data processing platform through the temperature data collector;

[0009] The data processing platform is based on the temperature difference between the fin temperature and the tube wall temperature. When the fire-facing side of the water-cooled wall tubes and water-cooled wall fins is in a clean state, the temperature difference is large; when the fire-facing side of the water-cooled wall tubes and water-cooled wall fins is in a dusty state, the temperature difference is small; the more serious the dusty side of the water-cooled wall tubes and water-cooled wall fins is, the smaller the temperature difference is. Therefore, the data processing platform obtains the dusty degree of each sootblower area, that is, the pollution rate, through linear calculation.

[0010] Preferably, the number of the fin thermocouples J=the number of the sootblowers N, and each sootblowers corresponds to one fin thermocouple.

[0011] Preferably, the number K of the tube wall thermocouples is much smaller than the number J of the fin thermocouples, and the number K of the tube wall thermocouples is ≤ M, and at most one tube wall thermocouple is arranged at each height.

[0012] Preferably, assuming that the contamination rate of the current sootblower area is W, then:

[0013] W=[T0-(Ta-Tb)] / T0

[0014] Wherein, Ta is the fin temperature measured by the fin thermocouple next to the sootblower corresponding to the current sootblower area;

[0015] Tb is the tube wall temperature measured by the tube wall thermocouple located at the same height of the sootblower corresponding to the current sootblower area;

[0016] T0 is the difference between Ta and Tb when the heating surface is clean, and is calibrated at the beginning of boiler operation after the sootblowing of the current sootblower is completed.

[0017] Preferably, the distance D is 1.5 meters.

[0018] Preferably, the soot blower is a steam soot blower, a hydraulic soot blower or a sonic soot blower.

[0019] Preferably, based on the contamination rate of the sootblower area obtained by the data processing platform, the boiler operator or the data processing platform determines whether to perform the sootblowing operation, thereby keeping the boiler water wall clean.

[0020] By adopting the above scheme, the beneficial effects of the present invention are:

[0021] (1) The present invention arranges the fin thermocouple near each soot blower. On the one hand, the number of fin thermocouples required is small. On the other hand, once it is detected that the contamination rate of the water-cooled wall area where the thermocouple is located is high, the soot blowing operation can be performed by controlling the soot blower near the thermocouple to keep the heating surface clean and monitor the soot blowing effect.

[0022] (2) According to the present invention, at most one wall thermocouple is arranged on each water-cooled wall next to the soot blower at the same height, which greatly reduces the number of wall thermocouples and the risk of water-cooled walls being damaged during the installation of the wall thermocouples, thus facilitating their wide-scale promotion and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the arrangement of sootblowers and thermocouples on one wall of a boiler water-cooled wall in an embodiment of the present invention;

[0024] Figure 2 Schematic diagram of the installation positions of the fin thermocouple and the tube wall thermocouple in the embodiment of the present invention;

[0025] In the figure, 1. boiler water-cooled wall; a-1—c-3, soot blower; 2. tube wall thermocouple; 3. fin thermocouple; 4. water-cooled wall tube; 5. water-cooled wall fin; 6. temperature data collector; 7. data processing platform. DETAILED DESCRIPTION

[0026] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0027] like Figure 1 and Figure 2 As shown, the boiler water wall soot monitoring system disclosed in the embodiment of the present invention includes 9 soot blowers a-1-c-3, 9 fin thermocouples 3, and 2 tube wall thermocouples 2 on the boiler water wall 1. Each soot blower corresponds to a fin thermocouple 3, and the fin thermocouple 3 is arranged next to the corresponding soot blower near the center line of the furnace wall. The two tube wall thermocouples 2 are arranged next to the fin thermocouples 3 at the bottom and top layers near the center of the furnace wall.

[0028] The fin temperature measured by the fin thermocouple 3 and the tube wall temperature measured by the tube wall thermocouple 2 are connected to the data processing platform 7 through the temperature data collector 6. The data processing platform 7 obtains the degree of soot contamination, that is, the contamination rate, of each sootblower area through linear calculation based on the temperature difference between the fin temperature and the tube wall temperature.

[0029] The working principle of the boiler water wall ash pollution monitoring system is:

[0030] When the water-cooled wall where the fin thermocouple 3 and the tube wall thermocouple 2 are located is in a clean state, the temperature difference measured by the fin thermocouple 3 and the tube wall thermocouple 2 is large; when the water-cooled wall where the fin thermocouple 3 and the tube wall thermocouple 2 are located is in a dusty state, the temperature difference measured by the fin thermocouple 3 and the tube wall thermocouple 2 is small; the more serious the dusty water-cooled wall where the fin thermocouple 3 and the tube wall thermocouple 2 are, the smaller the temperature difference measured by the fin thermocouple 3 and the tube wall thermocouple 2.

[0031] Assuming the contamination rate of the current sootblower area is W, we have:

[0032] W=[T0-(Ta-Tb)] / T0

[0033] Wherein, Ta is the fin temperature measured by the fin thermocouple next to the sootblower corresponding to the current sootblower area;

[0034] Tb is the tube wall temperature measured by the tube wall thermocouple located at the same height of the sootblower corresponding to the current sootblower area or the lower layer sootblower;

[0035] T0 is the difference between Ta and Tb when the heating surface is clean, and is calibrated at the beginning of boiler operation after the sootblowing of the current sootblower is completed.

[0036] The boiler water wall soot pollution monitoring system provided by the present invention arranges the fin thermocouple near each soot blower. On the one hand, the number of fin thermocouples required is small. On the other hand, once the water wall area where the thermocouple is located is monitored to have a high pollution rate, the soot blower near the thermocouple can be controlled to perform soot blowing operations to keep the heating surface clean and monitor the soot blowing effect. The present invention greatly reduces the number of tube wall thermocouples, can effectively reduce the risk of water wall damage during the installation of tube wall thermocouples, and is conducive to large-scale promotion and use.

Claims

1. A boiler water wall soot pollution monitoring system, wherein the boiler water wall has N soot blowers, N ≥ 1, the N soot blowers are located at M different heights, M ≥ 1, each height has n soot blowers, 1 ≤ n ≤ N, characterized in that: The monitoring system includes J fin thermocouples, K tube wall thermocouples, a temperature data collector, and a data processing platform, 1≤J≤N, 1≤K≤J; J fin thermocouples are arranged near J sootblowers respectively, the jth fin thermocouple is arranged at the water-cooled wall fin of the boiler water-cooled wall within a certain distance D from the jth sootblowers, j=1,…,J, and the fin temperature of the water-cooled wall fin is measured by the fin thermocouple; K tube wall thermocouples are respectively arranged at the outermost part of the back-fire side of the water-cooled wall tube of the boiler water-cooled wall adjacent to the K fin thermocouples, and are used to measure the tube wall temperature of the water-cooled wall tube; The fin temperature measured by the fin thermocouple and the tube wall temperature measured by the tube wall thermocouple are connected to the data processing platform through the temperature data collector; The data processing platform is based on the temperature difference between the fin temperature and the tube wall temperature. When the fire-facing side of the water-cooled wall tube and the water-cooled wall fin is in a clean state, the temperature difference is large; when the fire-facing side of the water-cooled wall tube and the water-cooled wall fin is in a dusty state, the temperature difference is small; the more serious the dusty side of the water-cooled wall tube and the water-cooled wall fin is, the smaller the temperature difference is. Therefore, the data processing platform obtains the dusty degree of each sootblower area, that is, the pollution rate, through linear calculation; The number of the fin thermocouples J=the number of the sootblowers N, and each sootblower corresponds to one fin thermocouple; The number K of the tube wall thermocouples is much smaller than the number J of the fin thermocouples, and the number K of the tube wall thermocouples is ≤M, and at most one tube wall thermocouple is arranged at each height.

2. A boiler water wall fouling monitoring system according to claim 1, characterized in that: Assuming the contamination rate of the current sootblower area is W, we have: W=[T0-(Ta-Tb)] / T0 Wherein, Ta is the fin temperature measured by the fin thermocouple next to the sootblower corresponding to the current sootblower area; Tb is the tube wall temperature measured by the tube wall thermocouple located at the same height of the sootblower corresponding to the current sootblower area; T0 is the difference between Ta and Tb when the heating surface is clean, and is calibrated at the beginning of boiler operation after the sootblowing of the current sootblower is completed.

3. A boiler water wall fouling monitoring system as claimed in claim 1, characterized in that: The distance D is 1.5 meters.

4. A boiler water wall fouling monitoring system as claimed in claim 1, characterized in that: The soot blower is a steam soot blower, a hydraulic soot blower or a sonic soot blower.

5. A boiler water wall fouling monitoring system as claimed in claim 1, characterized in that: Based on the contamination rate of the sootblower area obtained by the data processing platform, the boiler operator or the data processing platform determines whether to perform a sootblowing operation, thereby keeping the boiler water-cooled wall clean.

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