Study on High Temperature Air Combustion of Pulverized Coal

Abstract

The combustion behavior of pulverized coal in high temperature air combustion condition has been studied using a regenerative type furnace. High temperature air over 800℃ is produced by heat exchange from the exhaust gas using heat storage honeycombs. In order to control the ash deposition on the honeycombs, cyclone is used to collect fly ash in the exhaust gas. Pulverized coal is fed into the furnace at the rate of 7kg/h continuously along the center of the furnace. Excess air ratio is fixed to 1.2. Combustion behavior is recorded by CCD camera, and temperature distribution in the furnace is measured by thermocouple. Composition of the exhaust gas is measured by a gas analyzer. From the results, pulverized coal flame is stabilized by high temperature air although the inlet of pulverized coal and high temperature air is separated. NO_x concentration in the exhaust gas is reduced to 32% of that in the condition which pulverized coal and air is supplied axis symmetrically. Ash deposition on the honeycombs can be controlled using cyclone and soot blowing technique.