Selective non catalytic reduction (SNCR) of flue gas denitrification technology
The technology of: Selective non catalytic reduction (Selective Non-Catalytic Reduction, SNCR) process, or called heat DeNOx technique, is a kind of without catalyst, method of reduction of NOx. The reducing agent containing NHx groups (such as ammonia, ammonia or urea) is sprayed into the furnace temperature is 800 ¡æ ~ 1100 ¡æ region, the reducing agent rapid thermal decomposition into NH3 and other by-products, followed by NH3 and NOx in the flue gas of SNCR reaction and generate N2. A typical SNCR system by reducing agent storage tank, multilayer reducing agent is sprayed into the device and the corresponding control system. It has the advantages of simple process, convenient operation, the system flow chart are as follows. The SNCR process can be easily retrofitted in existing device. Because it does not need the catalyst bed, and only needs to store equipment reducing agent and injection system to be installed, so the initial investment relative to SCR process is much lower, operation cost and SCR process. Performance characteristics: 1, the denitrification effect is satisfactory: the application of SNCR technology in large-scale pulverized coal boilers, long-term field application in general can reach 30 ~ 50% of NOx removal rate. 2, the reducing agent and diverse easy: reducing agent for removal of NOx SNCR technology in general are nitrogen-containing substances, including ammonia, urea, cyanuric acid and ammonium salt (ammonium acetate, ammonium bicarbonate, ammonium chloride, ammonium oxalate, ammonium citrate etc.). But the best, practical is the most extensive application of ammonia and urea. 3, no two pollution: SNCR technology is a clean technology, no pollution of any solid or liquid or by-products, no two pollution. 4, the system simple, short construction time: SNCR technology is the most important reducing storage system agent and injection system, main equipment storage tank, pump, spray gun and the necessary pipes, measurement and control equipment. Because the equipment is simple, the installation of SNCR technology is short, only 10 days during the shutdown time, minor repairs can be completed the construction. 5, SNCR technology does not require major changes for the boiler combustion equipment and heating surface, the conventional mode of operation also does not need to change the boiler, has significant effect on operation parameters of the boiler will not. 6, the SNCR system equipment is easy to operate, high degree of automation, low failure rate, and stay online pumps have enough spare, valve device. SNCR available rate of not less than 95%.
