Patent ID: 8940062
Filing Date: 2015-01-27
Classification: C10J,F23C

Abstract:
1. A method for controlling a temperature in a combustion furnace in a gasification equipment comprising a gasification furnace for gasifying a raw material through formation of a fluidized bed by introduction of water vapor and a combustion furnace for blowing up with air the bed material introduced together with unreacted char from said gasification furnace to heat the bed material through combustion of said char, the bed material heated in said combustion furnace being separated from a combustion exhaust gas and returned to said gasification furnace, the method comprising: providing a first map for defining a feed rate of the char from the gasification furnace to the combustion furnace on the basis of a rate of the water vapor and a rate of the raw material to the gasification furnace at a rated point and a second map for defining as number an influence of a temperature in the gasification furnace and a circulated rate of the bed material on said feed rate of the char; reading out the feed rate of the char at the rated point from a current rate of the water vapor and a current rate of the raw material to the gasification furnace according to the first map, reading out an influence number from a current temperature in the gasification furnace and a current circulated rate of the bed material according to the second map, and multiplying the feed rate of the char at said rated point by said influence number to thereby calculate an actual feed rate of the char; providing a third map for defining a gross heat value of the char flowing into the combustion furnace on the basis of said actual feed rate and heat value of the char, and a fourth map for defining a heat value required for keeping a top of the combustion furnace at a commanded temperature on the basis of the commanded temperature in the top of the combustion furnace and a flow rate of air to the combustion furnace; reading out the gross heat value of the char flowing into the combustion furnace according to said third map, reading out the heat value required for keeping the top of the combustion furnace at the commanded temperature according to the fourth map and performing a subtraction between the both to thereby calculate a heat value required for keeping the temperature in the combustion furnace; providing a fifth map for determining an operation rate of an auxiliary fuel from said required heat value to perform an advanced control for an auxiliary fuel feeder so as to achieve said operation rate of the auxiliary fuel; and providing a proportional integrator for adding a regulated operation rate to said auxiliary fuel operation rate so as to make zero a difference obtained as a result of subtraction between the commanded temperature and a detected temperature in the top of said combustion furnace to perform a feedback control for said auxiliary fuel feeder.