USEING THE PULVERIZED COAL CONTAINED WITHIN TERTIARY AIR AS REBURNING FUEL TO REDUCE THE NO_x EMISSION

Nitrogen oxides(NOx) have been recognized as acid rain precursor that impose a significant threat to the environment. Coal combustion of power plant boilers is a major anthropogenic source of NOX During the past decade, our government pay more and more attention to environment protection. Therefor, we must take powerful measures to control NOX emission from power plant coal combustion. Reburning technology is a valid method.This paper focuses on NOx-emission problem of traditional units with hot air transferring pulverized coal. The main technical route of this paper is to use the pulverized coal contained within tertiary air to reduce the NOX emission as the reburning fuel.This paper consists of the following parts:Firstly, the physical properties (particle size distribution,specific area ,porosity ratio and pore volume) and pyrolysis characteristics have been studied in experiments with four kinds of coals. According to experimental results, the advantages of combustion characteristics of micro-pulverized caols are analysed on the theory.Secondly, the reconstructing plan is designed in details for a conventional system of the hot air transferring pulverized coal to reduce NOX emission. The plan's core is the pulverized coal in tertiary air is concentrated and then used as reburning fuel to control NOX emission when the mill is operating, at the same time, taking the staging combustion to guarantee low NOX emission while the mill stopping.At last, for easy to the boiler's running regulation ,the feasibility of neural network method for the monitoring of NOX emission is studied on the experimental furnace. It can be the basis on which neural network method may be used to monitor NOX emission of actual furnace.