Nitrogen oxide have be the second air pollutant after sulfur dioxide, its influence is increasing on acid rain, air quality and ground ozone concentration. With the rapid development of power industry, thermal units take more and more pressure to environment with nitrogen oxide. During national seeventh five years plan period, the nitrogen oxide discharge management should be enhanced. Low NOX burning technology and equipments of coal secondary combustion on power station boiler are low cost NOx emission technology. New thermal power units could adopt the technology and old units could adopt it in burning rebuild. It's also used with low NOx burner in boiler low NOx rebuilt system. It fill the gaps in this area.

This task source is our stand on ourself own feet exploitation when we take on national and local scientific research items. Up to now we have done the mechanism research, test research on small test equipment and preliminary demonstration test on small type power boiler. On this basis, we have done adaptability researched on kinds of coal, middle test equipment research, industry demonstration test on large capability boiler. We got the key data on industry application and made it industrialization.

Key technology: we researched the surface of burned coal in advanced test way and equipment, analysed the surface of burned coal in routine way and spoligotyping, researched the regularity for change of burned coal surface in fast pyrolysis, researched the burning character of coal and deoxidize character of NOx. Simulating the reaction condition of secondary burning area in tube-type settlement boiler, we have researched all process secondary combustion in medium test equipment, and got the chemistry equivalent ratio, dwell time in secondary combustion area and the granularity parameter of secondary combustion coal that impact rule of reducing NOx. Fine coal spout was set above main burning area to deoxidize NOx, the buring spout was set on secondary combustion spout to keep the burning in efficiency.

Innovation: optimize the aerodynamical of the secondary combustion coal entering the boiler, include that insufflation situation, insufflation angle and insufflation speed, so that could make the coal mixes with gas fully. It will improve the contact area well and speed up the rate of reaction, also Improve the effectiveness of NOx reduction and reduce NOx emissions, then the removal efficiency could more than 40%, and no impact with boiler function performance.

The system improved with foreign technology, it's simple and practical. We develop the level strength technology and fine coal secondary combustion with low NOx technoloy. Combine the level strength, double channels and secondary combustion technology to improve the performance of equipment. We research on the coal adaptability, middle test and set test, we work on industry test on large capability boiler and get the key technical data on industry application. The cases of the Commercialization of research findings: Neimenggu Yuanbaoshan power plant 600MW unit boiler and Shenhai thermal power corporation 200MW unit boiler. The recast make significant effect there. The buring equipment have be authorized by China patent bureau, the patent number of this utility model equipment is ZL 2006 2 0020077.6.