Online monitoring and analysis system for ammonia escape in boiler denitrification

1、 Product Overview (Denitration Laser Ammonia Escape Online Monitoring System (High Temperature Extraction Laser))

The integrated online monitoring system for denitrification ammonia escape (DST-1100 type) includes three major parts: pretreatment system, gas analyzer, and data processing and display. The sampling method of this system is in place high-temperature heat tracing extraction. The basic principle of this system is based on ultraviolet differential absorption spectroscopy (DOAS) technology and tunable semiconductor laser absorption spectroscopy (TDLAS) technology; The principle of UV differential absorption spectroscopy technology is that the same gas has different absorption in different spectral bands, and the absorption superposition of different gases in the same spectral band. Through algorithm analysis of continuous spectrum, multiple gases can be measured at the same time, effectively avoiding mutual interference of each component; Laser spectral gas analysis technology has been widely applied in various gas monitoring fields with high requirements for sensitivity, response time, background gas interference free, etc.

The denitration ammonia escape integrated online monitoring system produced by Zhengzhou Zhongwei Environmental Protection Equipment Co., Ltd. is durable and easy to install, especially suitable for monitoring gas emissions in many environmental and industrial processes, including coal-fired power plants, aluminum plants, steel plants, smelters, garbage power plants, cement plants, and chemical plants.

2、 Formation and harm of ammonia escape

2.1 Formation of ammonia escape

In the field of large-scale burning of fossil fuels, such as coal-fired power plants, denitrification devices with pre combustion or post combustion NOX control technology are installed. The post combustion NOX control technology can be either Selective catalytic reduction (SCR) or selective non catalytic reduction (SNCR), but the basic principle is the same regardless of which method is applied, Both reactions occur by injecting ammonia into the reactor and reacting with nitrogen oxides to produce water and N2. The injected ammonia can be directly in the form of NH3, or it can be released through urea decomposition before injection. Regardless of the form, controlling the total amount of ammonia injected and the spatial distribution of ammonia in the reaction zone can reduce NOX emissions.

If there is too little ammonia injection, it will reduce the reduction conversion efficiency. If there is too much ammonia injection, it not only cannot reduce NOX emissions, but also causes NH3 to escape from the reaction zone due to the excess ammonia. The escaped NH3 will react with the sulfate generated in the process to generate ammonium sulfate, mainly ammonium bisulfate. Ammonium salts can precipitate on the surface of solid components downstream of the boiler tail flue, such as on the fan surface of the air preheater, causing severe equipment corrosion and resulting in expensive maintenance costs. When the distribution of ammonia injected into the reaction zone does not match the distribution of NO and NO2, ammonia escape phenomenon can also occur. The high amount of ammonia escape accompanied by a decrease in NOX conversion efficiency is a very bad phenomenon and serious problem. For more details, please feel free to call (WeChat synchronization): 15713691937.

2.2 Hazards of ammonia escape

(1) Escaped ammonia gas causes waste of funds and environmental pollution;

(2) Ammonia escape will corrode the catalyst module, causing catalysis

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