Device and method for multiple-parameter measurement of combustion state of coal-fired boiler

Abstract

The invention discloses a device and a method for multiple-parameter measurement of a combustion state of a coal-fired boiler. The device comprises a central processing module, a light emitting module and a light receiving module, wherein a signal generator, a current controller and a temperature controller in the central processing module can be used for together modulating and driving a diode laser to emit a laser; the laser is transmitted to the light emitting module so as to be expanded in beam and collimated; then, the laser is contacted with gas to be tested in the flue of the coal-fired boiler and then is received and detected by the light receiving module; in addition, the optimal signal is converted into an electric signal which is transmitted to the lock-in amplifier I and the lock-in amplifier II in the central processing module respectively for demodulation; the demodulated signal is sent to a signal processor for analyzing and processing; and finally, an obtained value is displayed on a display screen. According to the device and the method provided by the invention, the system calibration is realized by a laser absorption spectroscopy and by utilizing the ratio of a secondary harmonic signal to a primary harmonic signal, wherein the primary harmonic signal and the secondary harmonic signal are demodulated by wavelength modulation spectroscopy technology; as a result, the use of a reference sample pool is avoided, the system structure is simplified and the system volume is reduced; the system accuracy is less than or equal to plus or minus 1%; and the device is high in accuracy, low in price, long in service life and free from maintenance.

Description

technical field [0001] The invention relates to a device and method for measuring multi-parameter gas concentration and temperature, which is mainly used for real-time on-line monitoring of the combustion state of coal-fired boilers in thermal power plants, coal-fired boilers in thermal power plants, and coal-fired boilers in petrochemical steel. Background technique [0002] The methods of monitoring combustion state parameters are generally divided into two categories: traditional physical monitoring methods (such as zirconia O2 analyzer) and optical monitoring methods. Traditional physical monitoring methods have low precision and slow response, which cannot meet the needs of new high-efficiency and energy-saving combustion control systems. At present, in my country's power generation industry, O2 analysis sensors based on zirconia have been widely used, but the life of zirconia analyzers is short, and the maintenance workload of the system is heavy. And the measurement ...

AI Technical Summary

Problems solved by technology

Traditional physical monitoring methods have low precision and slow response, which cannot meet the needs of new high-efficiency and energy-saving combustion control systems

At present, in my country's power generation industry, O2 analysis sensors based on zirconia have been widely used, but the life of zirconia analyzers is short, and the maintenance workload of the system is heavy.

However, infrared or thermocouples are used to measure the temperature, which is difficult to reflect the internal temperature of the furnace, and the service life is short.

[0003] On the other hand, due to the large volume of industrial boilers, traditional monitoring methods can only monitor the combustion state of a certain point in the boiler, and cannot truly reflect the real situation in the boiler; at the same time, the combustion instability in the boiler is usually around 500Hz. To provide effective feedback control information, the sensor must have a response rate of the kHz order, while the response rate of the zirconia analyzer is slow, which is far below the requirements of the combustion control system for the sensor

[0004] In addition, there is basically no effective detection method for the concentration detection of gas CO and CO2 produced in the combustion process. It can only be detected through flue gas emission, and the real concentration at the combustion point cannot be detected in real time.

[0005] In short, the accuracy, real-time, reliability and other performances of traditional physical monitoring methods are far from meeting the requirements of real-time monitoring of combustion systems. As a result, boilers in many thermal power plants in my country cannot be controlled to work near the optimal combustion point for a long time, resulting in huge waste. At the same time, there is also a large space for improving combustion efficiency.

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