AU660644B2

AU660644B2 - Coal and oil lance

Info

Publication number: AU660644B2
Application number: AU10226/92A
Authority: AU
Inventors: William J. Errington
Original assignee: Mount Isa Mines Ltd
Current assignee: Mount Isa Mines Ltd
Priority date: 1991-01-24
Filing date: 1992-01-14
Publication date: 1995-07-06
Anticipated expiration: 2012-01-14
Also published as: AU1022692A

Description

1 660644

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPEC I F I CATION FOR A STANDARD PATENT

ORIGINAL

1" I I .':Nme of Applicant: '...Actual Inventor: MOUNT ISA MINES LIMITED A.C.N. 009 661 447 William J. Errington Address for Service: SHELSTON WATERS 55 Clarence Street SYDNEY NSW 2000 0 oS Invention Title: "COAL AND OIL LANCE" Details of Ass 2iated Provisional Application No: PK4324 The following statement is a full description of this invention, including the best method of performing it known to us:-- 2 The present invention relates to smelting lances and in particular to a smelting lance for use in the smelting of non-ferrous metals.

In the smelting of non-ferrous metals a pyrometallurgical lance is used to convey air or oxygen and sometimes fuel (eg. oil or gas) to the molten material to assist in the smelting process. The lance is typically a vertically disposed pipe and may have a central fuel passaqe. Air flow down the lance is used for three purposes. The first is to promote mixing within the smelting material, the second is to provide air combustion in the smelt and the third is to cool the steel lance walls which might otherwise melt and fail.

Swirlers are used in the lances to create a turbulent air flow in the region of contact with the molten metal and to improve cooling of the lance walls.

In some cases pulverized coal as a fuel has been used as a substitute for oil or gas and has been injected via the control passage in a stoichiometric proportion to the oxygen or in slight excess or deficiency. In other cases coal as a reductant has been delivered to the surface of the molten, furnace bath via a furnace feed port.

It is an object of the present invention to provide a lance which ameliorates at least some of the disadvantages of the prior art.

According to the invention there is providd a lance comprising a first passage adapted to feed 3 particulate solids into a furnace, a second substantially annular passage generally coaxial with the first and adapted to deliver a gas to the furnace, and a third passage at least part of which extends intermediate the first and second passages, the third passage communicating with nozzle means at or adjacent the tip of the lance and adapted to deliver a fluid to the furnace, said nozzle means including a generally annular manifold having a plurality of substantially axially directed exit apertures for the fluid.

Preferably the lance delivers solids/gas/fluid below the bath surface.

In preferred embodiments, coal is fed via the first passage, air or oxygen enriched air via the surrounding annular passage, and oil via a feed-line in fluid communication with the third passage.

Preferably, the nozzle communicates with a manifold extending around the base of the nozzle from which a plurality of exits emerge. It is also preferable that 20 the nozzle is tapered to assist in distributing the air-flow.

It has not hitherto been practiced to inject these separate substances into the furnace via a simple submerged outlet pyrometallurgical lance.

A preferred embodiment of the present invention.

will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a schematic representation of a lance 3a according to the present invention; Figure 2 is a detailed view of the tip portion of the lance of Figure 1; Figure 3 is an end elevation of the lance of Figure 01 *foe* 0* 4 4 Figure 4 is a top end elevation of the nozzle of the present invention; Figure 5 is a schematic representation of the nozzle of Figure 4; Figure 6 is a bottom end view of the nozzle of Figures 4 and Figure 7 is a schematic representation of the feed line attachment of the present invention; and Figure 8 is a further view of the feed line attachment of Figure 7.

Referring to the drawings, the invention provides a lance 1 for injecting material into a furnace. The lance includes an inlet portion 2, an intermed"=te portion 3, and a tip portion 4.

The lance 1 is typically about 10 meters long with the majority of its length, say about 9 meters, comprising the intermediate portion 3. The lance is preferably 30 to 45 cm in diameter but can be down to 20 cm in diameter.

The lance provides a first passage 5 adapted to feed solids such as coal to the furnace, and a second generally annular passage 6 concentric with the first.

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The annular passage 6 is adapted to deliver gas such as air or oxygen enriched air to the furnace. A feed line 7 enters the lance through a side wall and connects with a further passage 8 to deliver a liquid such as oil to the discharge end of lance tip 4. A spider attachment 9 connects feed-line 7 with passage 8 in the interior of the lance within inlet portion 2. Passage 8 extends intermediate the first and second passages and communicates with a nozzle 10 adjacent the lance tip 4.

The inlet portion 2 of the lance includes means for connecting passages 5, 6 and 8 to sources of coal, air and oil respectively. Passages 5 and 8 project through the wall of the lance and are subsequently connected to the appropriate source. The mouth of passage 6 has flanges 11 adapted for connection with a suitable air supply.

Nozzle 10 is best seen in F.ares 4 to 5 which also show inner tube 5 and feed line 8 passing through the nozzle. Air passing through passage 6 travels around nozzle 10 and the tapered sides of the nozzle assist in distributing the air-flow. Oil passes through passage 8 to a circular manifold 12 extending around nozzle 10 and circumventing passage 5. From manifold 12 oil exits the nozzle through a series of exit apertures 13 to be evenly distributed with air in the surrounding passage 6. Coal in the particle size range of 100 micron to about 13 mm is preferably introduced into passage 5. The coal is thus preferably added via the lance to below the surface of the bath to act as an added reductant during the

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smelting process.

The attachment 9 to introduce the oil into the lance is shown in detail in Figures 7 and 8. Arms diverge outwardly from a central cylinder 16. Passage runs through cylinder 16 and oil feed line 7 connects with passage 8. Attachment 9 is secured in place within Z the inlet portion 2 of the lance by means of grub screws 6 in arms 15. Further bolts 17 act in securing attachment 9 within the lance. The arms 15 are arranged so as not to substantially impede the flow of air in passage 6.

The lance may be provided with one or more swirlers, blades or aerofoils to improve heat exchange between the air, the oil line and the coal duct.

Although the invention has been described with reference to specific examples it will be appreciated by those skilled in the art that the invention may be embodied in many other forms. For example, gas may be used as a fluid fuel in substitute for oil. Other nozzle configurations may also be employed.

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Claims

1. A lance comprising a first passage adapted to feed particulate solids into a furnace, a second substantially annular passage generally coaxial with the first and adapted to deliver a gas to the furnace, and a third passage at least part of which extends intermediate the first and second passages, the third passage communicating with nozzle means at or adjacent the tip of the lance and adapted to deliver a fluid to the furnace, said nozzle means including a generally annular manifold having a plurality of substantially axially directed exit apertures for the fluid.

2. A lance according to claim 1 wherein coal is £ed to the furnace via the first passage, wherein air or oxygen enriched air is fed to the furnace via the second passage, and wherein oil is fed to the furnace via the third passage.

3. A lance according to claim 1 or 2 wherein the nozzle means is disposed generally coaxially within the o 0 body of the lance and includes tapered sides converging in a downstream direction to facilitate air flow through the lance.

4. A lance according to any one of claims 1 to 3 wherein the first passage extends through the centre of the nozzle manifold and wherein the second passage extends around the nozzle manifold.

5. A lance according to any one of the preceding 8 claims wherein a feed-line enters the lance through a side wall thereof to direct the fluid into the third passage.

6. A lance according to claim 5, further including a spider attachment disposed within the lance and adapted to connect the feed-line with the third passage.

7. A lance according to claim 6 wherein said spider attachment includes a central body and a plurality of radially extending arms supporting the body centrally within the second passage.

8. A lance according to claim 7 wherein the first passage passes through the body of the spider attachment.

9. A lance according to any one of c_ .ims 6 to 8 wherein the spider attachment is secured in position by threaded members extending through the body of the ,lance and engaging said arms.

A lance according to any one of the preceding claims further including an inlet portion comprising means for connecting the first, second and third passages C to sources of particulate solid fuel, gas, and fluid *Soo respectively.

11. A lance according to claim 10 wherein said C particulate solid fuel is coal, wherein said gas is air e or oxygen enriched air, and wherein said fluid is oil.

12. A lance according to any one of the preceding claims further including an outer casing, the inlet end of which includes a radial flange adapted for connection with a suitable air supply. i\. x^rcy 9

13. A lance according to any one of the proceeding claims, further including a generally tubular discharge tip adapted to penetrate the surface of a molten bath within the furnace and thereby inject both coal and a fluid fuel below the surface of the bath.

14. A lance according to any one of the preceding claims wherein the body is between 5 and 15 meters long and between around 20 to 45 cm in diameter.

A lance according to any one of the preceding claims, further including swirling means to create a turbulent air flow in the region of contact with the furnace bath and to improve heat exchange between the respective passages.

16. A lance, substantially as hereinbefore described with reference to any one of the accompanying drawings. DATED this 24th Day of April 1995 MOUNT ISA MINEF Attorney: RUTH M. CLARKSON Fellow Institute of Patent Attorneys of Australia S* of SHELSTON WATERS 6*44.4 *4