Flue gas ammonia escape online monitoring analyzer system (high temperature extraction laser)
（ 脱硝激光氨逃逸在线监测系统（高温抽取激光) ） I. Product overview ( denitration laser ammonia escape online monitoring system (high temperature extraction laser) )
The integrated denitrification ammonia escape online monitoring system (TK-1100) is produced by our company with honor. This system includes three parts: pretreatment system, gas analyzer, and data processing and display. The sampling method of this system is in-situ high temperature heat 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 ultraviolet differential absorption spectroscopy technology is that the same gas has different absorption in different spectral bands, and different gases are in the same The absorption superposition effect of the spectral band, through the algorithm analysis of the continuous spectrum, can measure multiple gases at the same time, and effectively avoid the mutual interference of the components; the laser spectrum gas analysis technology has been widely applied to the sensitivity, response time, and background gas to avoid interference, etc. Various gas monitoring fields with higher requirements.
The integrated denitrification ammonia escape online monitoring system (TK-1100) produced by our company is durable and easy to install. It is particularly suitable for monitoring environmental and industrial process gas emissions, including coal-fired power plants, aluminum plants, steel plants, smelters, Waste-to-energy stations, cement plants and chemical plants.
Formation and harm of ammonia escape
2.1 Formation of ammonia escape
In the field of large-scale combustion of fossil fuels, such as coal-fired power plants, pre-combustion or post-combustion NOX control technology denitration devices are installed. Post-combustion NOX control technology can be selective catalytic reduction (SCR) can also be selective non-catalytic reduction (SNCR), but no matter which method is used, the basic principle is the same, that is, by injecting ammonia into the reactor to react with nitrogen oxides to produce water And N2. The injected ammonia can be directly in the form of NH3, or it can be first released through urea decomposition to obtain NH3 and then injected. Regardless of the form, the total amount of ammonia injected and the spatial distribution of ammonia in the reaction zone can be minimized. NOX emissions.
Too little ammonia injection will reduce the reduction and conversion efficiency. Excessive ammonia injection will not only reduce NOX emissions, but the excess ammonia will cause NH3 to escape from the reaction zone. The escaped NH3 will react with the sulfate produced in the process. Ammonium sulfate is formed, and most of them are ammonium bisulfate. The ammonium salt will precipitate on the surface of the solid components downstream of the flue at the tail of the boiler, for example, on the surface of the air preheater fan, which will cause severe equipment corrosion and therefore cause expensive maintenance costs. Ammonia escape phenomenon also occurs when the distribution of injected ammonia in the reaction zone does not match the distribution of NO and NO2. The escape of high ammonia content accompanied by the decrease in NOX conversion efficiency is a very bad phenomenon and a serious problem.
2.2 Hazards of ammonia escape
(1) The escaped ammonia gas is a waste of funds and environmental pollution;
(2) Ammonia escape will corrode the catalyst module, cause catalyst deactivation (ie failure) and blockage, and greatly shorten the catalyst life;
(3) Escaped ammonia gas will generate ammonium sulfate (corrosive and cohesive) with SO3 in the air, which will block and corrode the heat storage element of the air preheater located downstream from the out of stock;
(4) Excessive escaping ammonia will be absorbed by fly ash, which will cause the aerated block (grey brick) to be unavailable for sale;
Specifications and technical parameters
0-10.0ppm, 0-50.0ppm can be set according to user needs
Calibrated at the factory, no periodic calibration required
Input and output signals
4-20mA current loop, 750ΩMax, isolated
Alarm for concentration over-limit, abnormal temperature, and system failure
2 (expandable), contact load 24V, 2A
RS485, double-ended isolated
(-20) ～ 50 ℃
Heat tracing temperature
180 ℃ ～ 240 ℃
2 ～ 20L / min (can be customized according to user needs)
1000 × 1200 × 600mm (default size)
Introduction to the flow path of ammonia escape system
The flow path of this system is mainly composed of measurement flow path, backflush flow path, calibration flow path and scroll cooling flow path. The specific flow path diagram is as follows:
After the system enters the measurement state, the electric actuator drives the two-way ball valve to switch to the sampling gas path. Under the action of the drainage pump, the measured gas enters the NH3 module through the probe rod, the two-way ball valve, and the secondary filter. The NH3 module uses absorption The technology (TDLAS) analyzes the gas to obtain the concentration of NH3 (high temperature thermal wet method), and finally evacuates.
The system will enter the calibration state for automatic zero adjustment at this time. At this time, the two-way ball valve is switched to the calibration gas path, and the calibration solenoid valve is opened. Under the action of the drainage pump, the ambient air enters the gas chamber through the filter and the calibration solenoid valve. Residue the measured gas in the purge. After the purge is cleaned, zero the NH3 once. The system will enter the backflushing state to backflush the sampling probe. At this time, the two-way ball valve is switched to the backflushing gas path and backflushing. The solenoid valve opens, and the system automatically controls the backflush solenoid valve to open or close to achieve backflushing to the probe filter.
Five, ammonia escape system sampling and chassis
The device is a sampling device with the function of electric heating and heat tracing, which can heat itself and implement temperature control. This device is suitable for continuous collection of sample gas at inlet and outlet of SCR / SNCR device with high temperature and high dust concentration. The diagram is as follows:
Structure: The device consists of a sampling tube, a probe flange, a sampling flange tube, a filter element, a backflushing gas tank, a backflushing solenoid valve, and a probe heat preservation cover.
This system is integrated in the chassis, the specific dimensions are as follows: