US 4,427,372 AGranted

Method and apparatus for continuously burning particles in air stream in a vertical furnace

AssigneeNittetsu Mining Co., Ltd.

InventorsMorimasa Takesue, Hiroyasu Otsuka, Hiroyuki Yanagihara

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Abstract

In a method for continuously burning particles in a gas or oil heated vertical furnace in which the particles are charged from an uppermost part of the space, and the particles bed fluidized by a burning gas flow is formed in a vertically successive downward arrangement and then the burned particles are discharged out of the bottom of the furnace after cooling, the improvement comprises the steps of: providing the furnace with a plurality of downwardly vertically successive zone, including a precipitation zone of the particles at an uppermost part in the furnace, a lower upward flow velocity zone having low upward stream of the burning gas (referred to as "rich fluidized bed", hereinafter) and a higher upward flow velocity zone having high upward stream of the burning gas (referred to as "lean fluidized bed", hereinafter) underneath the precipitation zone wherein the lean fluidized bed is formed beneath and adjacent to the rich fluidized zone, and feeding the particles, burning them successively through the zones provided in said furnace by the burning gas and then discharging the burned particles from the bottom without cooling while being suspended and floated by the upward flow of the burning gas. And furthermore, an apparatus for continuously burning particles with air stream comprising particles inlet and a particle precipitation chamber provided in the top of a vertical furnace, a large-diameter column and a small-diameter column provided underneath the precipitation column connected by inverted conical section, a burned particle exhaust port formed through the conical section under the small-diameter column, and a plurality of fuel and air or combustion gas inlet provided at the small-diameter column and the conical section.

Claims13

Dependent claims

A vertical furnace for continuously burning particles, said furnace comprising:

(a) a vertically elongated substantially tubular structure defining, in a vertically successive downward arrangement:
(i) a precipitation chamber formed from imperforate vertical walls, said precipitation chamber having a first cross-sectional area;
(ii) imperforate walls forming a first frusto-conical zone connecting said precipitation chamber to the next lower chamber;
(iii) a rich fluidized bed chamber formed from imperforate vertical walls, said rich fluidized bed chamber having a second cross-sectional area;
(iv) imperforate walls forming a second frusto-conical zone connecting said rich fluidized bed chamber to the next lower chamber;
(v) a lean fluidized bed chamber formed from imperforate vertical walls, said lean fluidized bed chamber having a third cross-sectional area;
and
(vi) imperforate walls forming a third frusto-conical zone connecting said lean fluidized bed chamber to the bottom of said tubular structure;
(b) a gas discharge opening at the top of said precipitation chamber;
(c) a particle inlet port in said precipitation chamber or said first frusto-conical zone;
(d) a vertically oriented inlet port for gas and/or a burnable fuel at the bottom of said third frusto-conical zone;
(e) at least one inlet port for gas and/or a burnable fuel in said lean fluidized bed chamber, said second frusto-conical zone, or said third frusto-conical zone;
and
(f) a burned particle discharge port at the bottom of said third frusto-conical zone, wherein:
(g) said first cross-sectional area is larger than said second cross-sectional area, and said second cross-sectional area is larger than said third cross-sectional area and
(h) there are no inlet ports for gas and/or a burnable fuel in said rich fluidized bed chamber, said first frusto-conical zone, or said precipitation chamber,
whereby:
(i) said lean fluidized bed chamber is the zone of highest temperature and the temperature within the furnace decreases vertically from said lean fluidized bed chamber;
(j) the velocity of the gas in said lean fluidized bed chamber is higher than the velocity of the gas in said rich fluidized bed chamber, and the velocity of the gas in said rich fluidized bed chamber is higher than the velocity of the gas in said precipitation chamber;
and
(k) the density of the particles in said lean fluidized bed chamber is lower than the density of the particles in said rich fluidized bed chamber.

18 more elements

A method for continuous burning particles in a furnace comprising:

(a) a vertically elongated substantially tubular structure defining, in a vertically successive downward arrangement:
(i) a precipitation chamber formed from imperforate vertical walls, said precipitation chamber having a first cross-sectional area;
(ii) imperforate walls forming a first frusto-conical zone connecting said precipitation chamber to the next lower chamber;
(iii) a rich fluidized bed chamber formed from imperforate vertical walls, said rich fluidized bed chamber having a second cross-sectional area;
(iv) imperforate walls forming a second frusto-conical zone connecting said rich fluidized bed chamber to the next lower chamber;
(v) a lean fluidized bed chamber formed from imperforate vertical walls, said lean fluidized bed chamber having a third cross-sectional area;
and
(vi) imperforate walls forming a third frusto-conical zone connecting said lean fluidized bed chamber to the bottom of said tubular structure;
(b) a gas discharge opening at the top of said precipitation chamber;
(c) a particle inlet port in said precipitation chamber or said first frusto-conical zone;
(d) a vertically oriented inlet port for gas and/or a burnable fuel at the bottom of said third frusto-conical zone;
(e) at least one inlet port for gas and/or a burnable fuel in said lean fluidized bed chamber, said second frusto-conical zone, or said third frusto-conical zone;
and
(f) a burned particle discharge port at the bottom of said third frusto-conical zone,
wherein:
(g) said first cross-sectional area is larger than said second cross-sectional area, and said second cross-sectional area is larger than said third cross-sectional area;
and
(h) there are no inlet ports for gas and/or a burnable fuel in said rich fluidized bed chamber, said first frusto-conical zone, or said precipitation chamber,
said method comprising the step of controlling the input of gas through said vertically oriented inlet port and said at least one inlet port in said lean fluidizied bed chamber, said second frusto-conical zone, or said third frusto-conical zone and the input of particles through said particles inlet port such that:
(i) said lean fluidized bed chamber is the zone of highest temperature and the temperature within the furnace decreases vertically from said lean fluidized bed chamber;
(j) the velocity of the gas in said lean fluidized bed chamber is higher than the velocity of the gas in said rich fluidized bed chamber, and the velocity of the gas in said rich fluidized bed chamber is higher than the velocity of the gas in said precipitation chamber;
and
(k) the density of the particles in said lean fluidized bed chamber is lower than the density of the particles in said rich fluidized bed chamber.

20 more elements

Dependencies are inferred from the claim text.

Facts

Application: 06/339,452Filed 6 Jan 1982
Priority: JP 55-755226 Jun 1980
Granted: 24 Jan 1984
Term ends: Not estimatedThe source records don’t support an estimate.

Classification8 codes

F23C 99/005
Subject-matter not provided for in other groups of this subclass: suspension-type burning, i.e. fuel particles carried along with a gas flow while…
B01J 8/386
Being subject to a circulatory movement only: internally, i.e. the particles rotate within the vessel
C04B 2/12
Preheating, burning calcining or cooling: in shaft or vertical furnaces
C04B 7/44
Heat treatment, e.g. precalcining, burning, melting; Cooling: burning; Melting