System for monitoring coking and ash deposition of boiler in real time and judgment method

Abstract

The invention discloses a system for monitoring coking and ash deposition of a boiler in real time and a judgment method, and the system comprises a coking and ash deposition diagnosis device, a large slag weighing device and an ash weighing device; the large slag weighing device is mounted at the horizontal end of the slag conveying steel belt; the large slag weighing device is installed in a dust conveying pipeline of a dust remover, the large slag weighing device and the ash weighing device transmit collected data to the coking and ash deposition diagnosis device, and the coking and ash deposition diagnosis device compares the collected data with theoretical calculation data and then judges whether coking and / or ash deposition exist in a furnace or not. By adopting the system and the judgment method disclosed by the invention, an effective monitoring means can be provided for preventing coking and ash deposition in the furnace of a power plant, specifically, the conditions of coking and ash deposition in the furnace can be timely and effectively judged by continuously monitoring the large slag amount and the ash amount and combining the coal feeding amount of the boiler and the proportion of ash content in coal, and a basis is provided for optimizing ash blowing; the occurrence of such events is reduced, and the safe operation of the unit is ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of pulverized coal boiler operation monitoring, and in particular relates to a system and a judgment method for real-time monitoring of boiler coking and ash accumulation. Background Art

[0002] With the rapid development of new energy sources such as photovoltaics and wind power, coal-fired power units have become the primary source of peak load regulation for power grids. To ensure the development and absorption of new energy, adapt to its fluctuating weather patterns, ensure rapid response and power safety for both the power grid and users, and enhance power safety risk management and emergency response capabilities, coal-fired power units have become the primary source of peak load regulation for power grids. During peak load regulation, coal-fired power units experience low combustion efficiency and high auxiliary power consumption, resulting in a decline in overall power plant profitability. To mitigate this decline, power plant boilers are blending low-ash melting point, high-alkali coal, and other coals prone to coking, as well as those with high moisture and ash content, to reduce coal costs.

[0003] When boilers are burning low-ash melting point or high-alkali coals, which are prone to coking, they are prone to coking on the water-cooled walls and heating surfaces at the furnace outlet during continuous high-load operation. Furthermore, when boilers are burning high-ash coals during low-load operation, ash accumulation is particularly prevalent in areas such as the horizontal flue. Coking and ash accumulation not only impair the boiler's heat exchange and reduce combustion efficiency, but in severe cases, falling coke can damage water-cooling pipes, block slag outlets, and cause boiler shutdowns. Severe ash accumulation can also cause significant fluctuations in furnace negative pressure, leading to sudden drops and shutdowns, seriously impacting the safe operation of the boiler.

[0004] At present, the methods for monitoring coking and ash accumulation are all lagging and cannot timely warn of the coking and ash accumulation conditions. When they are discovered, the coking or ash accumulation is already serious and difficult to clean, which affects the safe operation of the boiler. Summary of the Invention

[0005] The purpose of the present invention is to provide a simple, reliable, real-time monitoring system and judgment method for boiler coking and ash accumulation; it can continuously monitor the amount of large slag and ash, and judge whether there is coking and ash accumulation in the furnace, and the judgment result provides a basis for the operation of the soot blowing system.

[0006] The technical solution adopted by the present invention is as follows: On the one hand, the present invention provides a system for real-time monitoring of boiler coking and ash accumulation, which is characterized by: including a coking and ash accumulation diagnostic device, a large slag weighing device and an ash weighing device; the large slag weighing device is installed at the horizontal end of the slag conveying steel belt, and is used to collect the large slag emission; the ash weighing device is installed in the dust collector ash conveying pipeline, and is used to collect the ash amount; the large slag weighing device and the ash weighing device respectively transmit the collected data to the coking and ash accumulation diagnostic device, and the coking and ash accumulation diagnostic device determines whether there is coking and / or ash accumulation in the furnace after comparing the collected data with the theoretical calculation data.

[0007] Preferably, the system further comprises a slagging partition monitoring device, which comprises pressure sensors installed around the furnace slag bin for monitoring pressure data at different positions in the slag bin.

[0008] Preferably, the system also includes multiple dust monitoring thermocouples installed in areas of the horizontal flue prone to dust accumulation, for monitoring temperature data at different locations. Specifically, the multiple dust monitoring thermocouples are arranged and installed in both the horizontal and vertical regions of the horizontal flue, and after installation, the multiple dust monitoring thermocouples each penetrate the horizontal flue wall by 10 cm to 50 cm, with the penetration distances of the multiple dust monitoring thermocouples varying.

[0009] On the other hand, the present invention also provides a method for determining boiler coking and ash accumulation based on the above system, which is characterized by comprising the following steps: Obtain the normal coking amount and normal ash accumulation amount during production through experiments; According to the coal feeding amount G of the boiler in a certain period of time m And the proportion of ash in coal quality A b Calculate the theoretical ash amount G corresponding to this time period l , G l =G m •A b ; During the production process, the actual slag amount G in the same time period is collected by the large slag weighing device and the ash weighing device. zs , measured ash content G hs ; The coking and dust accumulation diagnostic device makes comparative judgments on coking or dust accumulation; Ash accumulation judgment: For solid slag discharge boilers, such as G hs <0.85-0.9G l , then there is ash accumulation in the furnace; For liquid slag boilers, such as G hs <0.6-0.7G l , then there is ash accumulation in the furnace; Coking judgment: For solid slag discharge boilers, such as G zs <0.1-0.15G l , then there is coking in the furnace; For liquid slag boilers, such as G zs <0.3-0.4G l , there is coking in the furnace.

[0010] Preferably, by installing multiple pressure sensors around the furnace slag bin and setting a pressure warning value, when a pressure sensor detects a pressure signal and the pressure value is greater than the pressure warning value, it indicates that there is coking in the upper furnace water-cooled wall / superheater in this area.

[0011] Preferably, multiple dust accumulation monitoring thermocouples are installed in the dust accumulation-prone area of the horizontal flue to collect temperature values at different positions. When the temperature value collected by a group of dust accumulation monitoring thermocouples is lower than the flue gas temperature at that location, it indicates that dust accumulation exists at that location.

[0012] The beneficial effects of the present invention are as follows: the scheme of the present invention provides an effective monitoring means for preventing coking and ash accumulation in the furnace of a power plant. Specifically, by continuously monitoring the amount of large slag and ash, and combining the boiler coal feed amount and the proportion of ash in the coal quality, it is possible to timely and effectively judge the coking and ash accumulation conditions in the furnace, providing a basis for optimizing soot blowing; reducing the occurrence of such incidents, and ensuring the safe operation of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0014] Figure 1 Schematic diagram of the structure of the system of the present invention.

[0015] Figure 2 This is a schematic diagram of the ash accumulation monitoring thermocouple arranged in the flue in the present invention.

[0016] In the figure: 1. Large slag weighing device; 2. Pressure sensor; 3. Ash accumulation monitoring thermocouple; 4. Ash weighing device; 5. Coal feeder; 6. Coking and ash accumulation judgment device. DETAILED DESCRIPTION

[0017] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0018] like Figure 1 As shown, the present invention provides a system for real-time monitoring of coking and ash accumulation in a boiler, comprising a coking and ash accumulation diagnostic device 6, a large slag weighing device 1, and an ash weighing device 4. The large slag weighing device 1 is installed at the horizontal end of the slag conveyor belt to measure the amount of large slag discharged. The ash weighing device 4 is installed in the dust collector ash conveying pipeline to measure the amount of ash. The large slag weighing device 1 and the ash weighing device 4 each transmit the collected data to the coking and ash accumulation diagnostic device 6. The coking and ash accumulation diagnostic device compares the collected data with theoretically calculated data to determine whether coking and / or ash accumulation exists in the furnace.

[0019] Preferably, the system also includes a slagging zone monitoring device and ash accumulation monitoring thermocouples 3. The slagging zone monitoring device includes pressure sensors 2 installed around the furnace slag bin to monitor pressure data at different locations within the slag bin. Multiple groups of ash accumulation monitoring thermocouples are installed in areas of the horizontal flue prone to ash accumulation to monitor temperature data at different locations.

[0020] Specifically, such as Figure 2 As shown, multiple groups of ash monitoring thermocouples are installed at intervals along the horizontal flue, and each group of ash monitoring thermocouples contains 3 thermocouples. The end probes of the 3 ash monitoring thermocouples in each group are 10cm-50cm away from the horizontal flue wall, and the upward penetration distances of the ash monitoring thermocouples in each group are different. When the end probe of the thermocouple is covered by ash, the monitored temperature will be lower than the flue temperature at that location. In this embodiment, the 3 ash monitoring thermocouples are marked as the first thermocouple, the second thermocouple and the third thermocouple, respectively. The distances from the end probes of the first thermocouple, the second thermocouple and the third thermocouple to the horizontal flue wall are 15cm, 35cm and 50cm, respectively. The first thermocouple, the second thermocouple and the third thermocouple are used to judge preliminary ash accumulation, moderate ash accumulation and heavy ash accumulation, respectively; in this way, the degree of ash accumulation can be judged by the data monitored by the thermocouples in the same group, and corresponding processing can be made later.

[0021] The present invention also provides a method for determining boiler coking and ash accumulation based on the above system, and the specific process steps are as follows.

[0022] The normal coking and ash accumulation during operation are determined through testing. Specifically, after a cold start of the boiler, after 5-7 days of normal operation, and after two full soot blows, and with minimal changes in boiler steam-water parameters and flue gas temperature, the theoretical and measured ash and slag amounts are calculated. The difference between the theoretical and measured ash amounts is calculated to determine the normal ash accumulation; the normal coking amount is calculated by calculating the difference between the theoretical and measured slag amounts.

[0023] According to the coal feeding amount G of the boiler in a certain period of time m And the proportion of ash in coal quality A b Calculate the theoretical ash amount G corresponding to this time period l , G l =G m •A b .

[0024] During the production process, the actual slag amount G in the same time period is collected by the large slag weighing device and the ash weighing device. zs , measured ash content G hs .

[0025] The coking and dust accumulation diagnostic device makes comparative judgments on coking or dust accumulation.

[0026] Ash accumulation judgment: For solid slag discharge boilers, such as G hs <0.85-0.9G l , then there is ash accumulation in the furnace; For liquid slagging boilers, such as G hs <0.6-0.7G l , there is ash accumulation in the furnace.

[0027] Coking judgment: For solid slag discharge boilers, such as G zs <0.1-0.15G l , then there is coking in the furnace; For liquid slag boilers, such as G zs <0.3-0.4G l , there is coking in the furnace.

[0028] Preferably, multiple pressure sensors are installed around the furnace slag bin and pressure warning values are set. When a pressure sensor detects a pressure signal greater than the warning value, it indicates that coking is present in the upper furnace water-cooled wall / superheater in that area. The larger the pressure value, the heavier the coke and the more severe the coking in that area. Soot blowing should be performed in that area. If no soot is blown, it indicates that the corresponding area is coke-free and does not require soot blowing. In this way, the pressure sensor can sense the weight of the falling slag, determine the size of the coke, and identify the coke area, thereby optimizing the operation of the soot blower in the furnace.

[0029] Preferably, multiple ash accumulation monitoring thermocouples are installed in horizontal flue ducts prone to ash accumulation. Temperature values at different locations are collected. When the temperature value collected by a certain group of ash accumulation monitoring thermocouples is lower than the flue gas temperature at that location, it indicates that ash accumulation is present. The data monitored by multiple thermocouples in the same group can also be used to determine the severity of ash accumulation.

[0030] The solution of the present invention can timely and effectively monitor and determine whether coking and / or dust accumulation occurs, intervene in the treatment in advance, and ensure the normal operation of production, which has promotion and application value.

[0031] Although the present invention lists the above preferred embodiments, it should be noted that although technicians in this field can make various changes and modifications, unless such changes and modifications deviate from the scope of the present invention, they should be included in the protection scope of the present invention.

Claims

1. A system for real-time monitoring of boiler coking and ash accumulation, characterized by: It includes coking and ash accumulation diagnostic device, large slag weighing device and ash weighing device; The large slag weighing device is installed at the horizontal end of the slag conveyor belt to collect the large slag discharge volume; The ash weighing device is installed in the dust collector ash conveying pipeline to collect the ash amount; The large slag weighing device and the ash weighing device respectively transmit the collected data to the coking and ash accumulation diagnostic device, which determines whether coking and / or ash accumulation occurs in the furnace after comparing the collected data with the theoretical calculation data.

2. The system for real-time monitoring of boiler coking and ash accumulation according to claim 1, characterized in that: It also includes a slagging partition monitoring device, which includes pressure sensors installed around the furnace slag bin to monitor pressure data at different positions in the slag bin.

3. The system for real-time monitoring of boiler coking and ash accumulation according to claim 1, characterized in that: It also includes multiple groups of ash accumulation monitoring thermocouples installed in the ash accumulation-prone areas of the horizontal flue to monitor temperature data at different locations.

4. The system for real-time monitoring of boiler coking and ash accumulation according to claim 3 is characterized in that: Multiple groups of the ash monitoring thermocouples are installed at intervals along the horizontal flue, each group of ash monitoring thermocouples contains at least 3 thermocouples, the end probes of the ash monitoring thermocouples in each group are 10cm-50cm away from the horizontal flue wall, and the upward penetration distances of the ash monitoring thermocouples in each group are different.

5. A method for determining boiler coking and ash accumulation based on the system of claim 1, characterized in that: The steps include: Obtain the normal coking amount and normal ash accumulation amount during boiler operation through experiments; According to the coal feeding amount G of the boiler in a certain period of time m And the proportion of ash in coal quality A b Calculate the theoretical ash amount G corresponding to this time period l , G l =G m •A b ; During the production process, the actual slag amount G in the same time period is collected by the large slag weighing device and the ash weighing device. zs , measured ash content G hs ; The coking and dust accumulation diagnostic device makes comparative judgments on coking or dust accumulation; Ash accumulation judgment: For solid slag discharge boilers, such as G hs <0.85-0.9G l , then there is ash accumulation in the furnace; For liquid slagging boilers, such as G hs <0.6-0.7G l , then there is ash accumulation in the furnace; Coking judgment: For solid slag discharge boilers, such as G zs <0.1-0.15G l , then there is coking in the furnace; For liquid slagging boilers, such as G zs <0.3-0.4G l , there is coking in the furnace.

6. The method for determining boiler coking and ash accumulation according to claim 5, wherein: By installing multiple pressure sensors around the furnace slag bin and setting pressure warning values, when a pressure sensor detects a pressure signal and the pressure value is greater than the pressure warning value, it indicates that there is coking in the upper furnace water-cooled wall / superheater in this area.

7. The method for determining boiler coking and ash accumulation according to claim 5, wherein: By installing multiple sets of ash accumulation monitoring thermocouples in the ash accumulation-prone areas of the horizontal flue, temperature values at different locations are collected. When the temperature value collected by a set of ash accumulation monitoring thermocouples is lower than the flue gas temperature at that location, it indicates that ash accumulation exists at that location.

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