Flue gas denitration on-line continuous monitoring solution - Monitoring and Testing - Air Monitoring and Testing
Nitrogen oxide (NOx) is one of the main sources of air pollution, not only it has significant influence on global warming, but also involved in the destruction of the ozone layer. Technical measures to control NOx emissions can be divided into two categories: one is so-called source control, the characteristic is by a variety of technical means, to control NOx generation in the process of combustion reaction (i.e., low NOx combustion technology). Another kind is the so-called tail control, the characteristic is restoring the already generated NOx to N2 by some means, which is usually called flue gas denitration.
In the fields of large-scale burning of the fossil fuels, all installed denitration device of NOx control technology, through the injection of ammonia and nitrogen oxides in the reactor, produces water and N2. The requested ammonia can be directly in the form of NH3, or NH3 obtained by decomposition of urea, no matter what form, controlling injection amount and space distribution of ammonia in the reaction can maximize the reduction of NOx emissions. When ammonia injection is too little, it will reduce the reduction efficiency, when it is too much, it not only does not reduce NOx emissions, on the contrary the excess ammonia will lead NH3 escape from reaction zone. the escaped NH3 reacts with the sulphate which will produce ammonium sulfate, and ammonium sulfate are mainly heavy ammonium sulfate salt. Ammonium salt precipitates on the surface of downstream solid parts of the boiler tail flue. For example, precipitation on air preheater sector will cause serious corrosion of equipment, and therefore bring expensive maintenance costs. If the distribution of injection of ammonia does not match the distribution of NO and NO2, ammonia escape will happen. The situation of high amount of ammonia escape with reduction of NOx conversion efficiency is a very bad phenomenon and serious problem.
For the above demands, based on our years of gas analysis product research and development experience, high-performance on-line monitoring system such as GA-5000DN、GA-5000nao、CEMS-2001 series are designed for the denitration industries.
GA - 5000 DN uses tunable laser analysis technology to measure NH3 and so on. CEMS - 2001 series uses uv difference technology to measure NO, NO2 and SO2. GA - 5000 nao is in-situ type denitration integrated machine. It integrates tunable laser analysis technology with uv difference technology together, which can analyze NH3, NO, NO2 and SO2 simultaneously. Customers can choose a variety of combination plan according to needs.
- Using tunable laser analysis technology to sample and measure NH3, comparing with the method of in situ, it has the advantages of no influence of dust in the flue, as well as temperature and pressure fluctuations, which can realize the online calibration.
- Using ultraviolet difference absorption technology to measure NOx. Measurement accuracy is not affected by water and dust completely (gas phase has no absorption in ultraviolet, liquid water and dust have no selectivity in absorption of ultraviolet light, which belongs to the gradual change of spectrum), it has advantages of low detection limit, small temperature drift.
- Without any moving parts, high reliability, short response time.