Thermal Experimental Studies And Numerical Simulation Of NOx Reduction By Micronized Coal Reburning

Pollutant NOx emission is an increasing threat to environment and human health, which becomes an urgent problem to be solved. Coal combustion in power plant is a major source of NOx. Many control methods have emerged as the times require for solving the NOx emission problem. One of these is fuel reburning. In this paper, micronized coal powder reburning technology is brought forward and a series of exploring research work is carried out aiming at the key issues of fuel reburning such as NOx reduction efficiency and burnout rate.First research on physics and combustion characteristic of micronized coal is processed in this paper. The results of the change tendency of pulverized coal character with particle diameter are got from particle diameter determining test, hole structure analysis test and TG analysis test, which provide theory element for NOx reduction research with micronized coal reburning.After a lot of survey and careful design work, a one-dimensional test system with multi-function such as air stage and fuel reburning is built up. This system is a semi-industrial facility and can get instructive results for engineering utility. The temperature is controllable and resultant and reductive process of NOx can be simulated in furnace, which provide test element for NOx reduction research with micronized coal reburning.Using this system, research on NOx emission and burnout characters of the test facility are carried out. The results of influence on NOx emission and carbon in fly ash by coal type, coal particle diameter, furnace temperature and excess air are reached through tests. Then micronized coal reburning tests are processed, which show a remarkable effect results on NOx reduction and burnout rate.In this paper, the numerical simulations of micronized coal reburning are conducted. The influence on reburning efficiency by above-mentioned factors and NOx concentration along the furnace are studied. This simulation enriches the test results and gives out the global distribution of furnace temperature, NOx and other components, which provides a new way for the research work on NOx reduction by micronized coal reburning.In this paper, a primary scheme for micronized coal reburning is brought forward from equipment analysis and local test of a 670t/h boiler in Zhenhai Power Plant. The industrial experiments provide valuable experience for the application of the new technology.In a word, researches on micronized coal reburning are carried out with test studies at semi-industrial facility and numerical simulation in this paper. The results provide a useful reference and instruction for industrial utility.