The Measure Of Ammonia Escape Rate Online

Nitrogen is one of the atmospheric pollutants recognized around the world.With the rapid development of power industry in recent years, NOx emissionspresent the trend of increased year by year. Selective catalytic reduction (SCR)denitration technology is the highest denitration efficiency and market prospect ofdenitration technology, has become the first choice for efficient control NOxemissions in the world. Along with our country to improve the nox emission controlstandard, power plant, the application of SCR technology in our country will bemore and more widely. In the denitration process, spray levels of ammonia directlydefine the efficiency of out of stock. Ammonia injection quantity is little, out ofstock is not complete, cannot effectively reduce NOXemissions; Ammonia injectioncapacity is much, sold out excess ammonia is easy to escape the reaction zone, notonly cause environmental pollution, will be sold out of equipment corrosion. Soaccurate monitoring ammonia escape, can instantly provides a feedback signal forammonia injection system, optimization control of ammonia injection quantity,keeping ammonia escape at the lowest level and ensure the efficiency of out ofstock. In this paper, the ammonia escape online measuring the main job.Determine the based on tunable spectral absorption (TDLAS) technology forammonia escape measurement technology, the technology has the sensitive reaction,response speed and response time about in ns, magnitude measurement precisioncan reach ppm ppb level, even make it possible to real-time online measurementand control. At present, the online measuring technology has been widely used ingas, gas monitoring of environmental pollution.Set up a laboratory under thecondition of TDLAS measurement system, the system is mainly composed oftunable distributed feedback lasers, photoelectric detector, measuring chamber,lock-in amplifier, oscilloscope, signal generator and optical components,etc.Existing ammonia escape online monitoring system at home and abroad aresummarized, the advantages and disadvantages of the domestic out of stock afterthe reaction zone, the flue gas dust content, concentration of ammonia with lowprone, easy absorption, low temperature characteristics of biochemical reactions, anew measurement system is presented. The system has the following features:sampling representative, can realize the calibration, after dust of flue gas, the laser can be implemented to wear, light path signal stability, etc. This chapter selectedNH3is located at6529.184cm-1the absorption lines, based on the method ofwavelength modulation measurement. By the ratio of0~10ppm concentration,curves are obtained. Experimental results show that under the condition of strongabsorption, a second order approximation method of Beer-Lambert’s law andsecond-order Taylor series approximation, under the condition of the absorptionrate is larger still has a high measuring precision, thus effectively extend themeasuring range of wavelength modulation technology, makes the TDLAStechnology can be more widely used in industrial measurement environment. AndNH3trend curve obtained by field experiments, prove the validity of the spectrallines.