US3545903A

US3545903A - Burner for preheating a refractory lined vessel

Info

Publication number: US3545903A
Application number: US806448A
Authority: US
Inventors: Marshall J Mccullough
Original assignee: United States Steel Corp
Current assignee: United States Steel Corp
Priority date: 1969-03-12
Filing date: 1969-03-12
Publication date: 1970-12-08
Anticipated expiration: 1987-12-08

Description

Dec. 8, 1970 M. J. M CULLOUGH 3,545,903

BURNER FOR PREHEATING A REFRACTORY LINED VESSEL Filed March 12, 1969 FUEL 48 OXYGEN INVENTOR. MARSHALL J. MCCULLOUGH Attorney United States Patent Office BURNER FOR 7 Claims ABSTRACT OF THE DISCLOSURE A burner for injecting a fluid hydrocarbon fuel and oxygen into a refractory lined vessel includes coaxial inner and outer tubes with a transverse partition between the inside of the outer tube and the outside of the inner tubes intermediate their ends dividing the outer tube into a fuel receiving chamber at the end remote from the vessel and an oxygen receiving chamber at the end adjacent the vessel. A transverse collar at the discharge end of the burner has an inner ring of spaced apart ports extending therethrough inwardly toward the discharge end of the burner and an outer ring of spaced apart ports extending therethrough inwardly toward the discharge end of the burner. Long tubes extend through the partition and communicate with alternate ports of both rings.

This invention relates to a burner particularly adapted for pro-heating a refractory lined vessel prior to filling it with molten steel or other ferrous metal, and is an improvement on the burner disclosed in the co-pending application of Lyman Ser. No. 739,464 filed June 24, 1968 and now US. Pat. No. 3,480,376 of Nov. 25, 1969. The burner is particularly applicable for use with continuous in-line liquid steel degassing apparatus which is preferably preheated to a temperature between 2700 and 3000 F. The Lyman burner has performed better than other burners for its intended purpose, but I have found that the flame is often considerably hotter on its perimeter than at its center. For example, the temperatures may be 6000 F. and 2000 F., respectively.

It is therefore an object of my invention to provide a burner suitable for elficiently injecting fuel and oxygen into refractory lined vessels which are to be pre-heated, in which the temperature of the flame throughout its cross section does not vary greatly.

This and other objects will be more apparent after referring to the following specification and attached drawings, in which:

FIG. 1 is a sectional view of the burner of my invention taken on line I-I of FIG. 2; and

FIG. 2 is a view taken on the line IIII of FIG. 1.

Referring more particularly to the drawings, reference numeral 2 indicates a portion of a degassing chamber having a refractory lining 4. Apparatus such as shown in the co-pending application of Lyman Serial No. 750,168 filed Aug. 5, 1968, is illustrative of vessels which may be pre-heated according to the present invention.

According to my invention 1 provide a burner or gas injector 6 for delivering fuel and oxygen through a port 8 into the degassing chamber 2. Burner '6 includes two

concentric tubes

10 and 12 with a transverse partition 14 extending between the outer wall of tube 10 and the inner wall of tube 12 intermediate their ends. As shown the tube 12 is made of two sections 12A and 12B welded together with section 12A being smaller in diameter than section 12B. A collar 16 is attached to the forward end of

tubes

10 and 12 and bears against a water cooled collar 18 at the entry end of port 8. Collar 16 is provided with a cooling water chamber 20 and a central sight opening 22 aligned with tube 10. A central frusto-conical mix- Patented Dec. 8, 1970 ing chamber 24 is provided in collar 16 at the discharge end of the burner. An inner ring of spaced apart ports 26 extend through the collar 16 inwardly toward the discharge end of the burner and communicate with chamber 24. An outer ring of spaced apart ports 28 surround the inner ring of ports 26 and extend through the collar 16 inwardly toward the discharge end of theburner and communicate with chamber 24. The inner ports 26 are preferably parallel to outer ports 28. A protective ring 29 is preferably provided on the collar 16 and extends into port 8. Tubes 30 extend through partition 14 into communication with half of the

tubes

26 and 28. The tubes 30 are arranged in inner and outer rings of the same diameter as the inner and outer rings of

ports

26 and 28 and are so spaced that they communicate with

alternate ports

26 and 28 with the

remaining ports

26 and 28 being open to oxygen receiving chamber 32. The ratio of fuel ports to oxygen ports and the arrangement thereof may vary, but that shown is preferred. It will be seen that the tubes 30 are open to the fuel receiving chamber 34. A sight opening 36 in line with tube 10 is covered with a sight glass 38 which is held in place by retaining ring 40.

Fuel is introduced through a conduit 42 into chamber 34 and passes through tubes 30 and

ports

26 and 28 into mixing chamber 24. Oxygen is introduced through conduit 44 into chamber 32 around tubes 30 and passes through

ports

26 and 28 into the mixing chamber 24.

Valves

46 and 48 are provided for controlling flow of fuel and oxygen to the burner. The fuel used is preferably natural gas which is substantially all methane, but may also be any suitable fluid hydrocarbon fuel such as atomized fuel oil or fluidized powdered coal. The oxygen need not be pure oxygen, but must be a gas containing at least 50% oxygen. It is preferred that commercially pure oxygen be used. The oxygen-to-fuel ratio is adjusted to a value that will result in a combustion product composition that is reducing to iron oxides at high temperatures and yet sufficient to provide the necessary heat of combustion. With any fluid hydrocarbon fuel the CO to CO ratio is maintained between 0.06 and 0.22. When natural gas is the fuel, the volumetric oxygen-to-fuel ratio is between 0.8 and 1.1. With this ratio being maintained the gas firing rate is set at a value that will provide the desired pre-heating temperature. The injection velocities of the fuel and oxygen are maintained above the rate of flame propagation and should be maintained well below sonic velocities. It is preferred to have the velocities between 50 and 600 ft. per second. The

angled ports

26 and 28 cause the alternate fuel and oxygen streams to mix thoroughly and thus produces a uniform flame temperature as they burn when leaving the burner. Burning of the fuel and oxygen is continued until the refractory lining has been heated to the desired temperature which is generally between 2700 and 3000 F. Packing 50, which may be in the form of O-rings, is provided where necessary or desirable.

While one embodiment of my invention has been shown and described, it will be apparent that other adaptations and modifications may be made.

I claim:

1. A burner comprising a conduit having a discharge end, a transverse partition dividing said conduit into a fluid fuel receiving chamber and an oxygen receiving chamber, one of said chambers being adjacent the discharge end of said conduitand the other at the opposite end thereof, a collar arranged transversely of said conduit at the discharge end thereof, a plurality of spaced apart ports extending through said collar inwardly toward the discharge end of said burner, a plurality of open ended tubes extending through said partition, the total number of tubes being less than the number of ports and each tube communicating with one of said ports, the remaining ports being open to the chamber adjacent the discharge end of said conduit, means for delivering fluid fuel to the fuel receiving chamber, means for delivering oxygen to the oxygen fuel receiving chamber, an essential concave mixing chamber at the discharge end of said burner, said ports discharging into said mixing chamber toward the axis thereof, said fuel and oxygen combining to burn when they are discharged from said burner.

2. A burner according to claim 1 in which said ports are arranged in an inner ring and an outer ring with the tubes communicating with alternate ports in each ring.

3. A burner according to claim 1 in which the diameter of said collar is substantially greater than the diameter of the chamber adjacent the discharge end of said conduit and a cooling water chamber is provided within the collar.

4. A burner according to claim 3 including an inner tube within said conduit extending through said fuel and oxygen chambers to said collar, said collar has an opening therethrough aligned with said inner tube, and a closure for the end of said inner tube remote from said collar.

5. A burner according to claim 4 including flow control means for said fuel, and separate fiow control means for said oxygen.

6. A burner according to claim 5 in which said ports are arranged in an inner ring and an outer ring with the tubes communicating with alternate ports in each ring.

7. The combination of claim 1 including a refractory lined hollow structure at the discharge end of said burner, said hollow structure having an opening therein for receiving said fuel and oxygen from said burner.

References Cited UNITED STATES PATENTS 3,480,376 11/1969 Lyman 431-353 CARROLL B. DORITY, 111., Primary Examiner US. Cl. X.R.