Title of Invention

"AN IMPROVED OXY-GAS BURNER"

Abstract

An improved oxy-gas burner which is durable and capable of producing a relatively long, wide and hot flame at a reduced consumption of fuel gas and reduced pollution of environment caused by discharge of unburat fuel gas, comprising a central tube (1) for feeding gas, an outermost tube (10), a plate (1B) at the top end, a copper tip at the bottom end, characterised in that a plurality of relatively small diameter tubes (4), such as, of outer diameter 26.7 mm and wall thickness 3.9 mm for feeding oxygen and a plurality of relatively small diameter tubes (5), such as, of outer diameter 13.6 mm and wall thickness 1.8 mm for circulating cooling water are dispersedly located in the annular space between the said central tube and outermost tube, and that said annular space is divided into an upper chamber (6A) for holding inlet cooling water, an intermediate chamber (6B) for holding inlet oxygen and a lower chamber (6C) for holding outlet cooling water, by means of two plates (8 and 9) disposed across the burner internal space.

Full Text

The present invention relates to an improved oxy-gas burner for heating of newly lined vessels and ladles, and scraps,in relatively small-size electric arc furnaces as used in steel plants. The invention relates more particularly to an oxy-gas burner which is capable of producing a relatively long and wide flame of temperature upto 2000°C with coke oven gas and upto 2600°C with natural gas at a high safety margin during application under critical, environment of high temperature and pressure, at a reduced fuel consumption and pollution of environment by releass of unburnt fuel gases from the burner. The conventional oxy-gas burners comprise basically a central tube for supplying the fuel gases to the burner and one or more concentric outer tubes for supplying oxygen to the burner through the annular space between the outer tube or tubes and the central tube, The main drawback of the conventional oxy-gas burners is that the central tube used for supplying gases, outer concentric tube or tubes for supplying oxygen, other internal parts and outside wall of these burners are not adequately cooled during applications of the burners, causing damage of the burner tip by the high-current arcs of electric arc furnaces or by the high pressure atmosphere generated inside the vessels or reactors in which these burners are introduced during operation, and also of the burner tubes or gas/oxygen feeding hoses by the backward travelling flame entering into the inadequately cooled burners during idle period of the burners. - 2 - The objective of the present invention is to provide an improved oxy-gas burner in which the gas and oxygen feeding tubes and also the outside surface of the burner wall are cooled sufficiently for overcoming the said drawback of the conventional oxy-gas burners, The other objective is to provide an oxy-gas burner of higher fuel efficiency, and longer, wider and hotter flame generating capability with reduced pollution of environment and probability of being damaged during its operation compared with the conventional oxy-gas burners. The main constructional feature which distinguishes the invented burner from the conventional burners is that a plurality of relatively small diameter tubes are provided in separate positions around a central relatively large diameter tube,for feeding oxygen at the burner exit in the invented burner, whereas one or more outer tubes of diameter larger than that of the central tube are provided concentrically with the latter In the conventional burners for supplying oxygen at the burner exit through the. annular space between the said tubes. The use of multiple, dispersedly located, tubes of relatively small diameter assists on the one hand the supply of oxygen in separate streams of high velocity round the gas stream supplied through the central large diameter tube to cause thorough mixing of oxygen with the gas and hence complete combustion of the gas and also generation of a long and wide flame of high temperature; and on the other hand allows a - 3 - relatively rapid cooling of the burner tip and outside surfaces of said multiple small diameter oxygen supplying tubes and the central large diameter gas feeding tube, the said surfaces being in direct contact with the cooling water circulated in the invented burner. Thus the invention provides an improved oxy-gas burner which is durable and capable of producing a relatively long, wide and hot flame at a reduced consumption of fuel gas and reduced pollution of environment caused by discharge of unburnt fuel gas, comprising a celntral tube for feeding gas, an outermost tube, a plate at the top end, a copper tip at the bottom end, characterised in that a plurality of relatively small diameter tubes, such as, of outer diameter 26.7 mm and wall thickness 3•9 mm for feeding oxygen and a plurality of relatively small diameter tubes, such as, of outer diameter 13.6 mm and wall thickness 1.8 mm for circulating cooling water are dispersedly located in the annular space between the said central tube and outermost tube, and that said annular space is divided into an upper chamber for holding inlet cooling water, an intermediate chamber for holding inlet oxygen and a lower chamber for holding outlet cooling water, by means of two plates disposed across the burner internal space. The invention is now described fully and particularly in an unrestricted manner with reference to a particular embodiment the oxy-gas burner as illustrated in the accompanying drawings, in which Figure 1a is the longitudinal sectional view of the burner; Figure 1b is the bottom view of the burner; and . 4 - Figure 1c is the bottom view at Section B-B of the burner. Referring to Figs. 1a, 1b and 1c, the "burner comprises a centrally located tube (1) for feeding fuel gases received through gas inlet (1A) provided at the top end (1B); a plurality of tubes (4), preferably eight in number, of relatively small * diameter,^'dispersedly located around the central tube (1) with their axes lying along a circle, concentric with tube (1), preferably at an equal angular separation of 45° from the adjacent ones, for supplying oxygen received through inlet (4A); inlet tube (7A) and outlet tube (7B) supplying cooling water for the burner; tubes (5), typically four in number, distributed preferably at an equal angular separation of 90° from the adjacent ones, with their axes lying on a circle, concentric with tube (1), for circulating cooling water inside the burner. Two circular metal plates (8 and 9), each of preferred thickness 5 mm are provided across the burner to divide the burner internal space into three separate chambers (6A, 6B and 6C) of which the upper chamber (6A) is for holding the inlet cooling water, the lower chamber (6C) is for holding the outlet cooling water and the intermediate chamber (6B) is for holding the oxygen supplied through oxygen inlet tube (4A). Copper tip (2) having eight oxygen outlet inclined holes (2B) and a central gas outlet hole (2C) is fitted to form exit end (2A) of the burner. Typical height of copper tip (2) is 20 mm. The axes of holes (2B) are inclined inward at an angle of 20-40° with the burner axis. - 5 - Typical dimensions of the central gas feeding tube (1), each intermediate oxygen feeding tube (4), each intermediate water circulating tube (5), outermost tube (10), oxygen inlet tube (4A), water inlet tube (7A), water outlet tube (7B) and gas inlet tube (1A) are presented in Table I. Each of four water circulating tubes (5) passes through a hole made in plates (8 and 9) each and is welded to the upper surface thereof. The upper end of each tube (5) is disposed in upper chamber (6A) at a preferred distance of 31 mm from top end (1B) of the burner and its lower end is disposed in lower chamber (6c) at a preferred distance of 40 mm from exit end (2A) of the burner. Each of eight oxygen supplying tubes (4) passes through a hole in plate (8) and is welded to the upper surface thereof. The upper end of each tube (4) is disposed in intermediate chamber (6B) at a preferred distance of 70 mm from top end (1B) of the burner and its lower end is embedded at the upper end of each of eight holes (2B) in copper tip (2) to a depth of 8mm and welded thereto. Holes (2B) are inclined towards the burner axis at the exit end (2A) at a preferred angle of 20-40°. For operating the burner, cooling water is supplied at a pressure of about 2 kg/cm2 for preventing any gas from entering the burner to ensure safety against burning of the gas inside the burner. The preferred flow rate of the cooling water-in the burner is 3 m3/hour. The burner is capable of operating from fuel gases like coke oven gas, mixed gas or. blast furnace gas. Coke oven - 6 - gas can be fired at a maximum flow rate of 2000 Nnr/hour. The required purity of oxygen is 40 to 90% and required pressure of oxygen is 0.1 to 1.0 atmosphere. Field trials have been conducted on the invented burner under conditions of varying flow rate and pressure of oxygen (O2) and coke oven gas (COG) and oxygen to gas flow rate ratio. The temperature, length and characteristics of the flame produced under said different conditions are presented in Table II from which it is noted that (a) the temperature at the flame axis, at. a distance of 50 mm from the burner tip varies from 1371 to 1964°C and that at the flame tip varies from 948 to 1372°C, (b) the length of the flame varies from 2.2 to 3.0 m and (c) characteristics of flame varies from less yellowish to completely blue with large width at the top. The fuel gas consumption rate and pollution of environment from discharge of unburnt fuel gas have been found to be appreciably less for the invented burner in comparison with the conventional oxy-gas burners. - 7 - Table I Typical dimensions of tubes used in the burner. Central gas feeding tube (1) Oxygen feeding tubes (4) Water circulating tubes(5) Outermost tube (10) Oxygen inlet tube (4A) Cooling water inlet tube (7A) Cooling water outlet tube (7B) Gas inlet tube (1A) Outer diameter (mm) Wall thickness (mm) Length (mm) 73 5 930 26.7 3.9 868 13.6 1.8 879 168.3 5.15 924 26.7 3.9 50 26.7 3.9 50 26.7 3.9 50 47.8 2.9 60 - 8 - Table II Results of field trials conducted on the invented burner (I) (II) (III) (IV) (v) (VI) (VII) (VIII) (IX) (x) (XI) s1 02 02 No flow pressure rate (atmg) (Nm3/h) COG COG flow pressure rate (mmwg) (Nm3/h) Oxy- Temp at gas flame flow axis at rate 50mm ratio from burner tip(°C) Temp,of -Temp,,of SS metal flame at 50mm tip (°C) from burner tip (°C) Flame length (m) Flame characteristics 1. 160 1.8 277 350 0.58 1398 -- 2.2 Completely bluish 2. 160 3, 160 1.8 1.8 500 446 835 696 0.32 0.36 - 1425 1446 -- 3.0 2.4 Yellowish dark in the middle Less yellowish 4. 160 1.8 404 562 0.40 - 1444 -- 2.3 Bluish in tip middle, yellow outer 5. 160 1.8 357 445 0.45 - 1371 - 2.2 Bluish 6. 167 2.0 357 472 0.47 - 1427 -- 2.2 Slight expansion of blush zone, yellow outline 7. 167 2.0 311 393 0.54 - 1412 - 2.3 Sparkling bluish 8, 167 2.0 434 760 0,38 -- 1429 - 3.0 Yellow outer 9. 167 2.0 468 934 0.36 - 1420 - 2.5 bellow tunnel like 10. 167 2,0 398 720 -0,42 - 1539 - 2.4 Bluish 11. 167 i 2.0 428 - 0,39 1715 - 1372 Wide at the end Table II (Conta.) Besuts of-field trials conducted on the invented burnrt (I) (II) (III) (IV) (V) (VI) (VII) (VIII) (IX) (X) (XI) 12. 167 2.0 452 - 0.37 1964 - 1200 - - 13. 167 2.0 357 - 0.47 1913 - 1359 - Bluish 14. 167 2.0 286 - 0.58 1921 - 948 - Bluish 15. 154 1.5 495 - 0.31 1911 - 1192 - Large spread of flame 16. 154 1.5 391 - 0.39 1716 - 1112 - - We Claim :- 1. An improved oxy-gas burner which is durable and capable of producing a relatively long, wide and hot flame at a reduced consumption of fuel gas and reduced pollution of environment caused by discharge of unburnt fuel gas, comprising a central tube (1) for feeding gas, an outermost tube (10), a plate (1B) at the top end, a copper tip at the bottom end, characterised in that a plurality of relatively small diameter tubes (4), such as, of outer diameter 26.7 mm and wall thickness 3.9 mm for feeding oxygen and a plurality of relatively small diameter tubes (5), such as, of outer diameter 13.6 mm and wall thickness 1.8 mm for circulating cooling water are dispersedly located in the annular space between the said central tube and outermost tube, and that ,,said annular space is divided into an upper chamber (6A) for holding inlet cooling water, an intermediate chamber (6B) for holding inlet oxygen and a lower chamber (6C) for holding outlet cooling water, by means of two plates (8 and 9) disposed across the burner internal space. 2. The burner as claimed in claim 1, wherein the number of tubes for feeding oxygen is eight and the number of tubes for circulating cooling water is four. should be corrected 3. The burner as claimed in claims^ 1 and 2, wherein the .dispersed tubes for feeding oxygen are ^ parallel to the central tube with their axes lying on a circle concentric with the burner axis at an angular separation of 45° from the adjacent ones. - 11 - 4. The burner as claimed in any of the preceding claims, wherein the tubes for circulating cooling water are dispersed parallel to the central tube with their axes lying on a circle concentric with the burner axis at an angular separation of 90 from the adjacent ones. 5. The burner as claimed in any of the preceding claims, wherein the tubes for circulating cooling water are introduced through corresponding holes in two plates (8 and 9) and welded to the upper surface thereof, with their upper ends lying in the upper chamber (6A) and lower ends lying in lower chamber (6C). 6. The burner as claimed in any of the preceding claims, wherein the tubes for feeding oxygen are introduced through corresponding holes in plate (8) and welded to the upper surface thereof, with their upper ends lying in intermediate chamber (6B) and lower ends embedded and welded at the upper ends of the corresponding inclined holes (2B) made in copper tip (2). 7. The burner as claimed in any of the preceding claims, wherein the upper chamber is provided with one gas inlet tube (1A) and one cooling water inlet tube (7A), the intermediate chamber is provided with one oxygen inlet tube (MA) and the lower chamber is provided with one cooling water outlet tube (7B). - 12 - 8. An improved oxy-gas burner substantially as herein described aad illustrated in the accompanying drawings. - 13 - Dated this 24th day of December 1997. An improved oxy-gas burner which is durable and capable of producing a relatively long, wide and hot flame at a reduced consumption of fuel gas and reduced pollution of environment caused by discharge of unburat fuel gas, comprising a central tube (1) for feeding gas, an outermost tube (10), a plate (1B) at the top end, a copper tip at the bottom end, characterised in that a plurality of relatively small diameter tubes (4), such as, of outer diameter 26.7 mm and wall thickness 3.9 mm for feeding oxygen and a plurality of relatively small diameter tubes (5), such as, of outer diameter 13.6 mm and wall thickness 1.8 mm for circulating cooling water are dispersedly located in the annular space between the said central tube and outermost tube, and that said annular space is divided into an upper chamber (6A) for holding inlet cooling water, an intermediate chamber (6B) for holding inlet oxygen and a lower chamber (6C) for holding outlet cooling water, by means of two plates (8 and 9) disposed across the burner internal space.

Documents:

02443-cal-1997-abstract.pdf

02443-cal-1997-assignment.pdf

02443-cal-1997-claims.pdf

02443-cal-1997-correspondence.pdf

02443-cal-1997-description(complete).pdf

02443-cal-1997-drawings.pdf

02443-cal-1997-form-1.pdf

02443-cal-1997-form-2.pdf

02443-cal-1997-form-3.pdf

02443-cal-1997-p.a.pdf