AUXILIARY FUEL SUPPLY METHOD IN COAL-FIRED BOILER

摘要

PURPOSE:To make a drastic reduction of stabilizing fuel by a method wherein coal gas which is produced in a gasified furnace and not treated by such gas refining processes as dust removal, desulfurization etc. is sent directly to a boiler through a piping kept at a specified temp. and used as auxiliary fuel at the time of start or a low load operation. CONSTITUTION:Gas and unreacted char produced by the reaction of coal and air blown in a gasified furnace 5 are sent to a pulverized coal-fired boiler 1 through a gas cooler 21 and a produced gas piping 7 to be used as auxiliary fuel for the boiler. For this equipment, a dust removal device for the produced gas is omitted. The greater part of tar is not condensed at 250 deg.C and more and exists as gas. By utilizing the property of gas which does not adhere on a piping, thermometers A18 and B19 are placed at the inlet of a produced gas piping 7 to the boiler and the neighborhood of a connecting part to the boiler respectively. The temp. of a piping placed from the outlet of a gas cooler to the burner of the boiler is controlled to between 250 deg.C and 600 deg.C to prevent the clogging of the piping due to adhesion of tar on the inside of the produced gas piping or the piping damage due to a high temp. and the carbonization of char contained in produced gas.