Method and apparatus for controlling temperature in combustion furnace in gasification equipment

Patent metadata

Field	Value
Publication number	US-8940062-B2
Application number	US-201013395203-A
Country	US
Kind code	B2
Filing date	Oct 22, 2010
Priority date	Oct 28, 2009
Publication date	Jan 27, 2015
Grant date	Jan 27, 2015

Abstract

A char 7 feed rate at a rated point determined from a relationship between a current water vapor 3 flow rate and a current raw material 5 charge rate to a gasification furnace 1 is multiplied by a proper number determined from a relationship between a current gasification furnace 1 temperature and a current bed material 4 circulated rate to calculate an actual char 7 feed rate. A subtraction is performed between a gross heat value of the char 7 flowing into the combustion furnace 2 determined on the basis of the calculated char 7 feed rate and a heat value required for keeping a top of the combustion furnace 2 at a commanded temperature determined from a relationship between the commanded temperature and an air flow rate in the furnace 2 to determine a heat value required for keeping the combustion furnace 2 at the commanded temperature. An auxiliary fuel operation rate is determined from the determined heat value to perform an advanced control for an auxiliary fuel feeder 21 and is regulated such that a difference as a result of subtraction between the commanded and detected temperatures in the top of the furnace 2 becomes zero to perform a feedback control for the feeder 21.

First claim

The invention claimed is:

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.

2. An apparatus 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 apparatus comprising:
water vapor rate detection means for detecting a rate of the water vapor to the gasification furnace;
raw material rate detection means for detecting a rate of the raw material to the gasification furnace;
gasification furnace temperature detection means for detecting a temperature in the gasification furnace;
bed material circulated rate detection means for detecting a circulated rate of the bed material;
combustion furnace air flow rate detection means for detecting a flow rate of air to the combustion furnace;
combustion furnace temperature detection means for detecting a temperature in a top of the combustion furnace;
auxiliary fuel feed rate detection means for detecting a feed rate of an auxiliary fuel to the combustion furnace; and
a controller with
a first map for defining a feed rate of the char from the gasification furnace to the combustion furnace on the basis of the rate of the water vapor and the rate of the raw material to the gasification furnace at a rated point; a second map for defining as number an influence of the temperature of the gasification furnace and the circulated rate of the bed material on said feed rate of the char; a multiplier for multiplying the feed rate of the char at a rated point read out 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 by the number read out from a current temperature in the gasification furnace and a current circulated rate of the bed material according to the second map to thereby calculate an actual feed rate of the char;
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 subtracter for a subtraction between the gross heat value of the char flowing into the combustion furnace read out according to said third map and the heat value required for keeping the top of the combustion furnace at the commanded temperature read out from the commanded temperature in the top of the combustion furnace and the flow rate of air to the combustion furnace according to the fourth map to determine an heat value required for keeping the combustion furnace at the commanded temperature;
a fifth map for readout of an operation rate of an auxiliary fuel from said required heat value so as to output an advanced command to an auxiliary fuel feeder; and
a subtracter for performing a subtraction between said commanded temperature and a detected temperature in the top of said combustion furnace and a proportional integrator for regulating said operation rate of the auxiliary fuel such that a difference obtained by the subtracter becomes zero so as to provide a feedback control for said auxiliary fuel feeder.

Assignees

• Katagiri Tomoyuki
• Ihi Corp

Inventors

• Katagiri Tomoyuki

Classifications

• F23C10/28 Primary

  Control devices specially adapted for fluidised bed, combustion apparatus · CPC title

• C10J2200/158

  Screws · CPC title

• C10J3/723

  Controlling or regulating the gasification process · CPC title

• C10J2300/0976

  as steam · CPC title

• C10J2300/0996

  Calcium-containing inorganic materials, e.g. lime · CPC title