BURNER FOR SUBMERGED COMBUSTION MELTER

Abstract

The invention relates to a submerged combustion burner (1) and to a melter comprising submerged combustion burners (1). The burner comprises a substantially parallelepipedic body, the melt oriented face of which shows a longitudinal slot, two opposite walls of the slot comprising a series of nozzles each supplied separately with fuel and oxygen containing gas. The slot advantageously shows a narrow opening comprised between 10 and 30 mm, preferably between 15 and 25 mm, most preferably about 20 mm. The burner is advantageously made of steel plates, preferably high temperature resistant steel. The walls of the slot as well as the melt oriented face of the burner are advantageously cooled. According to the invention, the parallelepipedic burner body comprises a first external longitudinal volume showing a generally U-shaped cross-section and a second internal longitudinal volume fitted within the said first external longitudinal volume, showing also a generally U-shaped cross-section, one of the longitudinal volumes comprising a connection to a supply of oxygen and the other comprising a connection to a supply of fuel gas. The ends of the branches of the longitudinal volumes are connected to the burner nozzles. A flange is arranged around the parallelepipedic burner body at a distance from the melt oriented face of said body.

Claims

1. A submerged combustion burner (1) comprising a substantially parallelepipedic body (3), the melt oriented face (5) of which comprises a longitudinal slot (9), two opposite walls of the slot (9,9) comprising a series of nozzles (11) each supplied separately with fuel and with oxygen containing gas.

2. The burner of claim 1, wherein the slot (9) shows a narrow opening comprised between 10 and 30 mm, preferably between 15 and 25 mm, most preferably about 20 mm.

3. The burner of claim 1, wherein the nozzles (11) are arranged at a distance of the melt oriented face (5) of the burner, which corresponds to 1 to 3 times the width of the slot (9).

4. The burner of claim 1 wherein the series of nozzles (11) arranged in one (9) of the opposite side walls of the slot (9) are offset versus the series of nozzles (11) arranged in the other opposite side wall (9) of the slot.

5. The burner of claim 1 wherein the slot (9) reaches at a distance of 1 to 10 times, preferably 1 to 5 times, its width below the level of the nozzles (11) defined by the line going through the center of the nozzles arranged on one sidewall of the slot.

6. The burner of claim 1 made of steel plates, preferably high temperature resistant steel.

7. The burner of claim 1 wherein the walls (9,9) of the slot (9) are advantageously cooled by a cooling liquid, preferably water.

8. The burner of claim 1 wherein the melt oriented face (5) of the burner is cooled by a cooling liquid.

9. The burner of claim 1 wherein first and second longitudinal conducts (15,17) are provided at each longitudinal side of the slot (9), the first longitudinal conduct being connected to an oxygen source and to the nozzles (11) arranged in the corresponding sidewall of the slot and the second longitudinal conduct being connected to a fuel source and to the nozzles (11) arranged in the corresponding sidewall of the slot.

10. The burner of claim 1 wherein the parallelepipedic burner body (3) comprises a first external longitudinal volume (15) showing a generally U-shaped cross-section and a second internal longitudinal volume (17) fitted within the said first external longitudinal volume showing also a generally U-shaped cross-section, one of the longitudinal volumes (15) comprising a connection (16) to a supply of oxygen containing gas, preferably oxygen or oxygen enriched air, and the other (17) comprising a connection (18) to a supply of fuel, preferably fuel gas, the ends of the branches of the longitudinal volumes (15,17) comprising fluid connections to the burner nozzles (11).

11. The burner of claim 10 wherein the first external longitudinal volume (15) transports oxygen or oxygen enriched air and the second internal longitudinal volume (17) transports fuel.

12. The burner of claim 1 wherein a flange (7) is arranged around the parallelepipedic burner body (3) at a distance from the melt oriented face (5) of said body (3), designed to fasten the burner (1) to a melter bottom or side wall, below the level of the melt.

13. A submerged combustion melter (100) comprising melter bottom and side walls, a raw material discharge (110) and a melt outlet (109) and at least one burner (1) arranged below the level of the melt (103), at least one of the said burners being a burner of claim 1.

14. The submerged combustion melter of claim 13 comprising at least two, more preferably at least three, at least four or at least five and/or less than 20, less than 18, less than 16, less than 14, less than 12 or less than 10 of such submerged burners (1).

15. The submerged combustion melter of claim 13 characterized in that it is a glass melter in which the burner(s) (1) are arranged at the bottom of the melter.

16. The submerged combustion melter of claim 13 wherein the melter is a glass melter for the manufacture of glass fibers, mineral wool fibers, glass wool and stone wool fibers.

17. The submerged combustion melter of claim 13 characterized in that the melting chamber is substantially cylindrical, preferably with an internal diameter of the melting chamber of 1.5 m to-3 m, more preferably 1.75 to 2.5 m, and the melt height is about 0.75 m, about 0.8 m, about 0.85 m or about 0.9 m; and/or about 2.2 m, about 2 m, about 1.8 m, or about 1.6 m.

18. A method of introducing a flame and/or combustion products from a submerged combustion burner into a melt wherein the flame and/or the combustion products are injected through a narrow slot into a melt.

19. The method of claim 18 wherein the melt is a glass melt which is formed in to mineral fibers selected from glass fibers, continuous glass fibers, glass wool fibers and stone wool fibers.

Description

[0036] The present invention will be described in more details with reference to the attached drawings of which:

[0037] FIG. 1: is a perspective view of a preferred embodiment of a burner of the invention;

[0038] FIG. 2: is a longitudinal cross section through a submerged combustion burner of the invention;

[0039] FIG. 3: is a transversal cross-section through a submerged combustion burner of the invention, according to line A-A of FIG. 2;

[0040] FIG. 4: is an enlarged view of the top of FIG. 3;

[0041] FIG. 5: is a transversal cross-section through a submerged combustion burner of the invention, according to line C-C of FIG. 2; and

[0042] FIG. 6 shows a schematic representation of a melter of the invention.

[0043] The burner shown in FIG. 1 has a substantially parallelepipedic body 3 with a melt oriented surface 5 and comprises a flange 7 for mounting of the burner in a melter bottom or side wall. With reference more specifically to FIGS. 2, 3 and 5, it is shown that the melt oriented face 5 comprises a slot 9. A series of aligned burner nozzles 11 is arranged in the longitudinal side walls 9 and 9 of slot 9. The lower part of slot 9 is enveloped by a double wall 10 defining a space with walls 9 and 9 of slot 9 in which cooling fluid, such as water, is circulated. At the top of the burner, a double wall 5,12 defines a further space for circulation of cooling fluid which cools the melt oriented face at the top of the burner, which is in contact with fluid melt. The relevant cooling spaces are interconnected and comprise inlet connecting pipes 12 and 12 to be connected to a cooling fluid source, as well as an outlet connecting pipe 10. The nozzles are advantageously arranged at a distance from the melt oriented face of the burner, which corresponds to 1 to 3 times the width of the slot, between the cooling space at the melt oriented face of the burner and the cooling space enveloping slot 9. Opposite nozzles are preferably offset to each other. The substantially paralletepipedic body of the burner comprises two longitudinal volumes of substantially U-shaped cross-section, a first external volume 15 and a second internal volume 17 nested inside the U shape of the first volume 15. The end of the branches of the U-shape of the first volume 15 are connected to the burner nozzles 11. Similarly, the end of the branches of the U-shape of the second volume 17 are also connected to the burner nozzles 11. The first volume 15 is designed to transport oxygen and comprises a connection 16 to an oxygen supply. The second volume 17 is designed to transport fuel gas and comprises a connection 18 to a fuel gas supply. As is more apparent on FIG. 4, oxygen and fuel gas are mixed in nozzle 11 prior to injection into slot 9. The connections 16 and 18 are shown as longitudinally oriented lateral connections. In the alternative, connection 16 and/or connection 18 can also be provided as vertical connection, for example depending on the arrangement of the burner in the melter for which it is intended.

[0044] The burner is particularly suitable for a submerged combustion melter such as a melter shown in FIG. 5. A submerged combustion melter 100 may comprise at least one submerged combustion burner 1 as described. The combustible or combustion gases are distributed over a larger number of nozzle outlets, with concomitant increase of number of flames and hence exchange area for energy transfer between gas and melt.

[0045] The burners may be arranged through a wall or preferably a bottom of a submerged combustion melter and fastened thereto by a mounting flange 7 adapted for securing it into a furnace bottom, for instance by means of screws or other fasteners guided through an appropriate number of flange fastening holes 7 in order to tightly fasten the burner 1 at a furnace wall. The distance between the mounting flange 7 and melt oriented face 5 of the burner is sufficient for the burner to traverse the melter wall or bottom and to protrude into the melter. This arrangement allows to maintain the burner flames at a desired distance from the relevant wall or bottom. Suitable cooling of the burner as described above thus protects the burner from excessive wear.

[0046] A submerged combustion melter of the invention comprises a furnace comprising a melting chamber 101 equipped with at least one burner 1 as described, which contains a melt 103 and communicates with an upper chamber 105 and a chimney 107 for evacuation of fumes. These hot gases may be used to preheat the raw material and/or the fuel gas and/or oxidant used in the burners. The fumes escaping from the bath may be kept under high pressure and may travel through fresh raw material in order to promote heat exchange and preheat said raw material. The fumes generally are filtered prior to release to the environment, optionally following dilution with fresh air to reduce their temperature.

[0047] The injected gas keeps the molten mass in a state of agitation, that is a bubbly mass. The heat transmission is thus significant and the stirring of the bath is favorable to the homogeneity of the finished product. Because of the relatively high number of flames, the energy exchange area between gas and melt is increased compared to conventional burners; this can further improve the energy efficiency of the melter.

[0048] The melt may be withdrawn from the melt chamber 101 through a controllable outlet opening 109 preferably located in the furnace chamber side wall, essentially opposite a raw material feeder device 110.

[0049] The furnace wall advantageously comprises a double steel wall cooled by a cooling fluid, preferably water. Cooling water connections are provided at the external furnace wall. The flow of cooling liquid is preferably sufficient to withdraw energy from the inside wall such that melt can solidify on the internal wall and the cooling liquid, here water, does not boil.

[0050] If so desired, the furnace may be mounted on dampers which are designed to absorb vibrational movements.

[0051] The melter is particularly advantageous for manufacture of glass fibers, mineral wool, glass wool or stone wool. Its energy efficiency reduces energy consumption and its flexibility allows for easy change of raw material composition. Its ease of maintenance and low capital cost are also advantageous.