Coal blocking early warning method for coal falling pipe of coal feeder of CFB boiler

Abstract

The present application provides a kind of CFB boiler coal feeder coal pipe coal blocking early warning system, it is related to coal feeder technical field.The CFB boiler coal feeder coal pipe coal blocking early warning system, including coal feeder sealing air flow parameter transmitter, coal feeder sealing air pressure parameter transmitter, coal feeder coal pipe coal blocking early warning signal parameter transmitter, coal blocking coefficient parameter transmitter, low selection threshold device module, set value module, bias set value module, switching module, adder module, divider module.The technical problem of CFB boiler coal feeder coal pipe early warning difficulty is solved, compared with traditional coal blocking early warning method, this method is more sensitive, advanced and accurate, can find coal pipe coal blocking phenomenon earlier, timely adjust coal supply and take coal blocking dredging measures, guarantee unit safe and stable operation.

Description

Technical Field

[0001] This invention relates to the field of coal feeder technology, specifically to a method for early warning of coal blockage in the coal feeder chutes of a CFB boiler. Background Technology

[0002] In CFB boilers of thermal power plants, the coal feeding system mainly consists of raw coal hoppers, belt feeders, and connecting coal chutes. The coal fed is mainly low-calorific-value coal, and the coal type is often unstable. When the coal has a high moisture content or a large amount of coal slime, it is easy for coal to stick to the coal chutes, reducing the flow area and causing coal blockage in the coal chutes and feeders. The traditional solution is to install a coal blockage detection device at the tail of the feeder and a vibratory air cannon to clear blockages from the feeder outlet to the furnace coal chutes. When the coal blockage detection device alarms or the feeder current exceeds the limit, it is considered that the coal chutes or feeders are blocked, the feeder is stopped, and the vibratory air cannon is started to clear the blockage. When the blockage is severe, manual clearing is required, which is time-consuming and labor-intensive. In addition, there is a backflow of hot flue gas in the furnace during the clearing process, which seriously affects the personal safety of the clearing personnel. If it is difficult to clear and restore in a short time, it will cause unit load fluctuations and threaten the safe and stable operation of the unit. The reason for this is that the blockage in the coal chute cannot be detected in time. By the time the blockage detection device alarms or the current of the coal feeder exceeds the limit, the blockage situation is often already very serious, which is a serious delay. Furthermore, the blockage detection device is prone to false alarms due to the influence of coal type and installation location, and cannot reflect the blockage situation in a timely and accurate manner in actual production operation. Summary of the Invention

[0003] (a) Technical problems to be solved

[0004] To address the shortcomings of existing technologies, this invention provides a method for early warning of coal blockage in the coal feeder chutes of a CFB boiler, solving the problem of difficulty in providing early warning of coal blockage in the coal feeder chutes of a CFB boiler.

[0005] (II) Technical Solution

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: a CFB boiler coal feeder coal chute blockage early warning system, comprising a coal feeder sealing air flow parameter transmitter, a coal feeder sealing air pressure parameter transmitter, a coal feeder coal chute blockage early warning signal parameter transmitter, a blockage coefficient parameter transmitter, a low selection threshold module, a set value module, an offset set value module, a switching module, an adder module, and a divider module.

[0007] Preferably, the system achieves early warning by configuring these parameters and modules in the distributed control system configuration software of the thermal power plant.

[0008] A method for early warning of coal blockage in the coal feeder chutes of a CFB boiler specifically includes the following steps:

[0009] S1. Install air volume transmitters and sealing air pressure transmitters in the sealing air duct of the coal feeder. Sum the sealing air flow of all normally operating coal feeders and divide by the sum of the sealing air pressure of all normally operating coal feeders.

[0010] S2. The average value obtained is added to the bias setting value to obtain the reference threshold. Finally, the coal feeder's coal drop pipe is blocked by measuring whether the ratio of the coal feeder's sealing air flow rate and sealing air pressure is less than the threshold.

[0011] S3. When coal blockage occurs in the coal drop pipe at the lower end of the coal feeder, the sealing airflow of the coal feeder shows a downward trend, while the pressure shows an upward trend. Therefore, the coal blockage coefficient curve shows a downward trend. Once it falls below the threshold, a coal blockage warning signal can be triggered.

[0012] Preferably, the method further includes using the ratio of the sealing air volume to the sealing air pressure of the coal feeder as a coal blockage coefficient. This coefficient changes significantly during the coal blockage process of the coal feeder, reacts quickly, and shows a more obvious trend, which can alert operators to coal blockage abnormalities earlier.

[0013] (III) Beneficial Effects

[0014] This invention provides a method for early warning of coal blockage in the coal feeder chute of a CFB boiler. It has the following beneficial effects:

[0015] This invention provides a method for early warning of coal blockage in the coal feeder chute of a CFB boiler. This invention solves the technical problem of difficulty in providing early warning of coal blockage in the coal feeder chute of a CFB boiler. The purpose is to provide a method and system for early warning of coal blockage in the coal feeder chute of a CFB boiler. To prevent the positive pressure high-temperature flue gas from the boiler combustion chamber from backflowing into the coal feeder through the coal feeder chute and damaging the feeder belt, a special sealing air supply line provided by the cold primary air is designed at the head of each coal feeder. Flow and pressure measuring points are installed to monitor the sealing condition of the coal feeder, ensuring that the positive pressure high-temperature flue gas from the boiler combustion chamber does not backflow into the coal feeder. When coal blockage occurs in the coal chute at the lower end of the coal feeder, an early warning system is established. The coal feeder's sealing airflow shows a decreasing trend while the pressure shows an increasing trend. This invention determines whether the coal feeder's chutes are blocked by measuring whether the ratio of the coal feeder's sealing airflow to its pressure (defined as the coal blockage coefficient) is less than a threshold. If it is less than the threshold, it is determined that there is a tendency to blockage, triggering a coal blockage warning. The threshold is determined by adding an offset setting value to the average value obtained by dividing the sum of the sealing airflow of all normally operating coal feeders by the sum of the sealing air pressure of all normally operating coal feeders. Compared with traditional coal blockage warning methods, this method is more sensitive, proactive, and accurate, and can detect coal blockage in the chutes earlier, adjust the coal feed rate in time, and take measures to clear the blockage, ensuring the safe and stable operation of the unit. Attached Figure Description

[0016] Figure 1This is a schematic diagram of the structure of the present invention;

[0017] Figure 2 This is a schematic diagram of the process for installing the air volume transmitter and the sealing air pressure transmitter in the sealing air duct of the coal feeder according to the present invention.

[0018] Figure 3 A summary table of the features of the modules used in this invention;

[0019] Figure 4 This is a historical trend graph showing the actual coal blockage coefficient and coal blockage switch of the present invention. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Example:

[0022] like Figure 1-4 As shown, this embodiment of the invention provides a CFB boiler coal feeder coal chute blockage early warning system, including a coal feeder sealing air flow parameter transmitter, a coal feeder sealing air pressure parameter transmitter, a coal feeder coal chute blockage early warning signal parameter transmitter, a blockage coefficient parameter transmitter, a low selection threshold module, a set value module, an offset set value module, a switching module, an adder module, and a divider module.

[0023] By configuring these parameters and modules in the distributed control system configuration software of thermal power plants, early warning can ultimately be achieved.

[0024] A method for early warning of coal blockage in the coal feeder chutes of a CFB boiler specifically includes the following steps:

[0025] S1. Install air volume transmitter and sealing air pressure transmitter in the sealing air duct of the coal feeder. Figure 2 The sum of the sealing airflow of all normally operating coal feeders is divided by the sum of the sealing air pressure of all normally operating coal feeders.

[0026] S2. The average value obtained is added to the bias setting value to obtain the reference threshold. Finally, the coal feeder's coal drop pipe is blocked by measuring whether the ratio of the coal feeder's sealing air flow rate and sealing air pressure (defined as the coal blockage coefficient) is less than the threshold.

[0027] S3. When coal blockage occurs in the coal drop pipe at the lower end of the coal feeder, the sealing airflow of the coal feeder shows a downward trend, while the pressure shows an upward trend. Therefore, the coal blockage coefficient curve shows a downward trend. Once it falls below the threshold, a coal blockage warning signal can be triggered.

[0028] The method also includes using the ratio of the sealing air volume to the sealing air pressure of the coal feeder as the coal blockage coefficient. This coefficient changes significantly during the coal blockage process of the coal feeder, reacts quickly, and shows a more obvious trend, which can alert operators to the abnormal coal blockage earlier.

[0029] Figure 4 The actual coal blockage coefficient and the historical trend of the coal blockage switch are as follows: the coal blockage coefficient started to decrease at 15:15:00, and the coal blockage switch protection was triggered at 15:43:00; the coal blockage early warning coefficient is activated 28 minutes earlier than the coal blockage switch protection.

[0030] Based on the above method and system, the No. 1 coal feeder sealing airflow parameter transmitter 1 is connected to the first input terminal i1 of the switching module M2, the setpoint module M1 is connected to the second input terminal i2 of the switching module M2, the No. 1 coal feeder operating signal is connected to the switching terminal S1 of the switching module M2, the output terminal of the switching module M2 is connected to the first input terminal i3 of the adder module M5, the No. n coal feeder sealing airflow parameter transmitter 2 is connected to the first input terminal i4 of the switching module M4, the setpoint module M3 is connected to the second input terminal i5 of the switching module M4, and the No. n coal feeder operating signal is connected to the switching module M4. The switching terminal S2, the output terminal of the switching module M4 is connected to the second input terminal i6 of the adder module M5, the output terminal of the adder module M5 is connected to the first input terminal i13 of the divider module M11, the No. 1 coal feeder sealing air pressure parameter transmitter 1 is connected to the first input terminal i7 of the switching module M7, the setpoint module M6 is connected to the second input terminal i8 of the switching module M7, the No. 1 coal feeder operating signal is connected to the switching terminal S3 of the switching module M7, the output terminal of the switching module M7 is connected to the first input terminal i9 of the adder module M10, and the No. n coal feeder sealing air pressure parameter transmitter 2 is connected to... The first input terminal i10 of the switching module M9 is connected to the first input terminal i11 of the setting value module M8. The operating signal of the nth coal feeder is connected to the switching terminal S4 of the switching module M9. The output terminal of the switching module M9 is connected to the second input terminal i12 of the adder module M10. The output terminal of the adder module M10 is connected to the second input terminal i14 of the divider module M11. The output terminal of the divider module M11 is connected to the first input terminal i15 of the adder module M13. The bias setting value module M12 is connected to the second input terminal i16 of the adder module M13. The adder module M13... One end of the output of 13 is connected to the threshold parameter transmitter, and the other end is connected to the set value sp terminal of the low selection threshold module M15. The sealing air flow parameter transmitter 1 of No. 1 coal feeder is connected to the first input terminal i17 of the divider module M14. The sealing air pressure parameter transmitter 1 of No. 1 coal feeder is connected to the second input terminal i18 of the divider module M14. One end of the output of the divider module M14 is connected to the No. 1 coal blockage coefficient parameter transmitter 3, and the other end is connected to the input terminal i19 of the low selection threshold module M15. The output terminal of the low selection threshold module M15 is connected to the coal blockage early warning signal of the No. 1 coal feeder's coal drop pipe.

[0031] Setting value modules M1, M3, M6, and M8 are all setting value modules with a setting value of 0.

[0032] The low-selection threshold module M15 is a low-selection threshold module with a set value of a threshold.

[0033] The offset setting module M12 is an offset setting module with a setting value of -20, which can be changed by the operator according to the actual production operation of the coal feeder.

[0034] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for early warning of coal blockage in the coal feeder chute of a CFB boiler, applied to an early warning system for coal blockage in the coal feeder chute of a CFB boiler, characterized in that: The system includes a coal feeder sealing air flow rate parameter transmitter, a coal feeder sealing air pressure parameter transmitter, a coal feeder coal drop pipe blockage early warning signal parameter transmitter, a blockage coefficient parameter transmitter, a low selection threshold module, a set value module, an offset set value module, a switching module, an adder module, and a divider module. The system is configured to perform the following steps: S1. Install air volume transmitters and sealing air pressure transmitters in the sealing air duct of the coal feeder. Sum the sealing air flow of all normally operating coal feeders and divide by the sum of the sealing air pressure of all normally operating coal feeders. S2. The average value obtained is added to the bias setting value to obtain the reference threshold. Finally, the coal feeder's coal drop pipe is blocked by measuring whether the ratio of the coal feeder's sealing air flow rate and sealing air pressure is less than the reference threshold. S3. When coal blockage occurs in the coal drop pipe at the lower end of the coal feeder, the sealing airflow of the coal feeder shows a downward trend, while the pressure shows an upward trend. Therefore, the coal blockage coefficient curve shows a downward trend. Once it is lower than the reference threshold, a coal blockage warning signal can be triggered. The coal blockage coefficient is the ratio of the sealing air volume to the sealing air pressure of the coal feeder. This coefficient changes significantly during the coal blockage process, reacts quickly, and shows a more obvious trend, which can alert operators to coal blockage anomalies earlier.

2. The method for early warning of coal blockage in the coal feeder chute of a CFB boiler according to claim 1, characterized in that: It also includes implementing early warning by configuring these parameters and modules in the configuration software of the distributed control system of thermal power plants.

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