CA1199837A

CA1199837A - Furnace burners

Info

Publication number: CA1199837A
Application number: CA000409423A
Authority: CA
Inventors: William I. Joyce
Original assignee: Babcock Power Ltd
Current assignee: Doosan Babcock Ltd
Priority date: 1981-08-14
Filing date: 1982-08-13
Publication date: 1986-01-28
Also published as: SE8204660D0; DE3229864A1; SE8204660L

Abstract

ABSTRACT

The invention provides a furnace burner that operates with pulverized fuel. Heated combustion air flows with a rotational movement along a burner tube (9,119) and a slurry of pulverized fuel in water is discharged into the air from nozzles (14,114).
The effect of the air, and the extended residence time resulting from the rotation of the air, will effect drying of the fuel before it reaches the furnace opening (2,102).

Description

~Improvements in or rel~ing to Furnacs ~urners"

DESCRIPTION

This invention relates to burnsrs by which fuel may bs burnt in a furnace and is conc~rned to facilitate the USB of pulverized fuel supplied from a source in the form af a slurry comprising pulverised fuel mixed with water.

The invention may bs sesn in, in the operation of a furnace burner, inkroduoing warm combustion air into a burnsr tube to flow with a rotational movement along the burner tube into the furnace, and discharging a slurry o~f pulverised fus~ and watsr into ths air to movs along the tube entrai~s~ in ths air.

The ;nvsntion also providss a furnace burner having a burner tube, ~eans by which combustion air may b8 introduced into the tube to flow along the tube with a rotational movemsnt, and m~ans by whioh a slurry of pulverized fuel and water may bs discharged into the air to move along ths tube entrained in the air.

By way o~ example, emhodiments of the invention ; will now bs ds~cribed with rsfzrence to the accompanying drawings in which:
Figure 1 shows in vertical axial cross s~ction : a burnsr, arrangsd for the combustion of pulveri~sd : fuel, mountzd at the wall o~ a furnace~ and Figure 2 shows in v~rtical axial cross section a modiflcation o~ what i~ shown in Figurs 1.

A
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In Figure 1, a furnace wall is denoted by 1O The wall has a burner opening 2 leading from windbnx 3 that is supplied through an opening 4 in the bottom with heated air..

A burner mouth 5 is formed around the burn~r opening 2 and a ligh~-up and stabilization oil tube B, having impellors ~a at its outle~ end, disGharga~
concentrically through the mouth 5O Concentrically around the tub2 8 is the burner tube 9O This com-1û prises an inlet part 9a, that is convergent towards the ~urnace. The wider znd is separated by a gap from the end wall 3a of a windbox 3, and the narrower znd opens to an outlet part 9b of constant cross-section~ Surrounding the part 9b is a secondary swirl register 10. ThQ gap between the wider end of the tube 9 and the end wall 3a of the windbox 3 is occupied by inlet vanes 11, cont.rolled by a sleeve d~mper 12, that permits air to ~low from the windbox 3 into the tube 9 and impart rotational movement to the air flowing into thQ tube 9.

An array of atomizing nozzles 14 is distributed araund the oil tube B and arranged to dischargs radially outwardly into air 3dmittsd between the vanes 11. The nozzles 14 ars supplied through pipe 1S from a source lnot shown) of a slurry of pulverizsd fual mixed with water.

3~

In operation of the burner that has been described, with air admitted between the vanes 11 and slurry discharged From the nozzles 14, ths dischargad slurry i~ entrained in the incoming air 5 and is therefore taken along a spiralli~g path that converges towards the furnace. The residence time in khe burner tube is therefore extended 50 that whilsk the slurry may be in the optimum condition ~or supply to the nozzles 14, but too moist for the 10 most efficient combustion of the fuel9 its axtended psriod in the heated air will effect drying. The fuel will khsrefore be more readily combustible and flame stability will be enhanced~ The residence time in the burner tube is promoted by its conical form.
15 The dryin~ action of ths heat will be re-in~orced by a sort of scrubbing e~ect resulting from the dis-charge of the atomized slurry at one velocity into the rotationally moving pre-heated air at anothar.

The parts of the burner illustrated in Figure 20 2 that are similar to parts of the burner illustrated in Figure 1 are denoted by the 6ame reference numbers, to which 100 has been added. The essential diPference lies in the form cf the ~urnsr tube, of which the outlet part 109~ leads through the swirl register 110.
25 The inlet part~ 119, however, whilst being o~ conical form, tapers towards the rear wall 103a of the wind-box, Tha inlet vanes 111 through which air passes into the part 119 lie between the wider end of the part 119 and the secondary sw;rl register 110~ No~zles 114 30 through which akomi~ed slurry may be discharged into the heated air swirling in the part 119 are disposed around the part 109b.

3~7 In use of the apparatus shown in Figure 2, the swirling air first flows away from the furnacs along a pa~h that, by change af direction, lsads then to the furnace~ Thus, the swirling occurs in the air 5 flowing to the furnace but in a direction away from the ~urnace, At the rear wall 103a, the direction of flow reverses and air, and the entrained slurry, flow thence into the furnace. By embodying this changY o~ direction, the residsnce time of the slurry in hsated air is fur~her increased~

It will be noted that in each of the embodi-ments described, th~ entire burner can be introduced into the windbox through an openin~ that is oP a diameter suf~icien~ly large to accept the swirl register ~0 ~or 110). Whilst the drying air admitted by ths vanes 11 ~or 111) and the secondary air admitted through the swirl register 10 ~or 110) como from a common windbox~ it is 2nvisagsd that the drying air could be supplied fro~ a separate source. Burners such as have been described may be produced by the ready modification of burners that have previously been installed for the combustion o~ heavy ~uel oilO

Claims

The embodiment of the invention in which an exclusive property or privilege is claimed are defined as follows:-

1. In the operation of a furnace burner, introducing combustion air into a burner tube to flow with a rotational movement along the burner tube into the furnace, and discharging a slurry of pulverized fuel and water into the air to move along the tube entrained in the air.

2. In an operation as claimed in claim 1, the air flows rotationally along a path that converges, in the direction of flow of the air, and the slurry is discharged into the wider part of the path.

3. In an operation as claimed in claim 2, the con-vergence of the path along which the air flows points away from the furnace, and the converging path is succeeded by a path in which the air flows back through the convergence into the furnace chamber.

4. In an operation as claimed in claim 1, the slurry is discharged radially outwardly in-to the air from a plurality of nozzles disposed concentrically about the axis of rotation o-P the air.

5. A furnace burner having a burner -tube, means by which combustion air may be introduced into the tube to flow along the tube with a rotational movement, and means by which a slurry of pulverized fuel and water may be discharged into the air to move along the tube entrained in the air.

6. A -furnace burner as claimed in claim 5, in which the burner tube is convergent and means is provided -for introducing the combustion air into the wider end of the burner -tube.

7. A furnace burner as claimed in claim 6, in which the wider end of the convergent tube is nearer the furnace than the narrower end and encircles an opening through which the air escapes towards the furnace, and the narrower end is closed by a wall opposite the open-ing.

8. A furnace burner as claimed in claim 7, in which the opening is defined by a cylinder co-axial with the burner tube and of which the inlet end projects towards the wall beyond the means by which combustion air may be introduced into the burner tube.

9. A furnace chamber as claimed in claim 8 in which a plurality of nozzles is distributed round, and mounted on, the cylinder, the nozzles discharge radially out-wardly and serve as the means by which the slurry may be discharged.

10. A furnace burner as claimed in claim 5 in which the means for discharging the slurry includes a plurality of nozzles disposed concentrically within the burner tube and discharging radially outwardly.