SUBMERGED COMBUSTION MELTER

Abstract

The invention relates to a submerged combustion burner (1) and to a inciter comprising submerged combustion burners (1). The burner comprises at least one oxidant feeding tube, at least one fuel feeding tube, a burner head having a peripheral envelope, the fuel and oxidant feeding tubes abutting against the burner head, at least two, preferably at least three, peripheral outward directed nozzles, each of the nozzles having a nozzle outlet, the nozzle outlets being arranged on a peripheral line on the peripheral envelope of the burner head, the nozzle outlet axis being inclined by an angle of 5 to 30° to the horizontal, and the nozzles practiced in the burner head being connected to the oxidant feeding tube and to the fuel feeding tube.

Claims

1. Submerged combustion burner (1) comprising at least one oxidant feeding tube (5,9), at least one fuel feeding tube (7), a burner head (11) having a peripheral envelope (13), the fuel and oxidant feeding tubes (5,7,9) abutting against the burner head (11), at least two, preferably at least three, peripheral outward directed nozzles (21), each of the nozzles having a nozzle outlet (23), the nozzle outlets (23) being arranged on a peripheral line (25) on the peripheral envelope (13) of the burner head (11), the nozzle outlet axis (22) being inclined by an angle of 5 to 30° to the horizontal, and the nozzles (21) practiced in the burner head (11) being connected to the oxidant feeding tube (5,9) and to the fuel feeding tube (7).

2. The burner of claim 1 characterized in that it comprises a circular burner head (11).

3. The burner of claim 1 characterized in that the feeding tubes (5,7,9) are concentric.

4. The burner of claim 1 characterized in that it comprises two feeding tubes.

5. The burner of claim 1 characterized in that it comprises three concentric feeding tubes (5,7,9), wherein the internal feeding tube (5) is an oxidant feeding tube, the middle feeding tube (7) is a fuel feeding tube and the external feeding tube (9) is an oxidant feeding tube.

6. The burner of claim 1 characterized in that part at least of the burner length is enveloped by a cooling jacket (31),

7. The burner of claim 6, characterized in that the cooling jacket (31) extends over part of the length of the feeding tubes (5,7,9) up to the burner head (11), the cooling jacket (31) having a first connecting tube (32), the burner head (11) comprises a burner cap (33) defining a burner head space (35) between burner cap (33) and burner head (11), the burner head (11) further comprises through holes (27,28,29) connecting the jacket (31) with the burner head space (35), and a cooling fluid feeding tube (39) extending essentially concentrically in the internal gas feeding tube (5) and connecting the burner head space (35) with a second connecting tube (41).

8. The burner of claim 1 characterized in that the burner head comprises at least two, preferably at least three nozzle bores (22) extending essentially radially through the burner head (11) starting from the nozzle outlet (23), each nozzle bore (22) being connected by feeding bores (27,28,29) to the relevant feeding tubes (5,7,9) extending up to and abutting against the burner head (11).

9. A submerged combustion melter comprising a melting chamber (103) equipped with at least one submerged combustion burner of claim 1, which is designed to contain a melt.

10. The submerged combustion melter of claim 9 comprising at least two, more preferably at least three, at least four or at least five and/or less than 30, less than 25, less than 20, less than 18, less than 16, less than 14, less than 12 or less than 10 of such submerged burners (1).

11. The submerged combustion melter of claim 9 characterized in that it is a glass melter in which the burner(s) (1) are arranged at the bottom of the melter.

12. The submerged combustion melter of claim 9 wherein the metier is a glass melter for the manufacture of glass fibers, mineral wool fibers, glass wool or stone wool fibers.

13. The submerged combustion melter claim 9 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.

14. A method of introducing a flame and/or combustion products from a submerged combustion burner into a melt through a multitude of nozzles essentially radially arranged in a burner head, the nozzle outlets of said nozzles being inclined by 5 to 30° to the horizontal.

15. The method of claim 14 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

[0031] The present invention will be described in more details with reference to the attached drawings of which:

[0032] FIG. 1: is a perspective view of a preferred embodiment of a burner of the invention;

[0033] FIG. 2: is a longitudinal cross section through a submerged combustion burner of the invention;

[0034] FIG. 3: is a partial longitudinal section according to a different plane from the one used in FIG. 2;

[0035] FIG. 4: is an enlarged cross-section through the burner head; and

[0036] FIG. 5 is a schematic representation of a submerged combustion melter.

[0037] The illustrated submerged combustion burner 1 comprises an internal oxidant feeding tube 5, a middle concentric fuel feeding tube 7, an external concentric oxidant feeding tube 9, and a burner head 11 having a peripheral envelope 13. The fuel and oxidant feeding tubes 5, 7, 9 abut against the burner head 11. The burner head 11 is advantageously circular and equipped with a multitude of peripheral outward directed nozzles 21, each of the nozzles 21 having a nozzle outlet 23 arranged on a peripheral line 25 on the peripheral envelope 13 of the burner head 11. The nozzle outlet axis 22 is inclined by an angle of 5 to 30° to the horizontal. Each nozzle 21 practiced in the burner head 11 is connected to the oxidant feeding tubes 5 and 9 and to the fuel feeding tube 7 by respective feeding bores 27, 28 and 29. Oxidant feeding tube 5 shows a connecting pipe 6 for connection to an oxidant gas source, such as a source of technical oxygen or oxygen enriched air or air. Fuel feeding tube 7 shows a connection pipe 8 for connection to a fuel source, such as a source of natural gas, propane or butane gas. Similarly, oxidant feeding tube 9 comprises a connection pipe 10 for connection to an oxidant gas source which may be the same or different from the oxidant gas source connected to feeding tube 5. Part or all of the feeding tubes may intermittently be connected to an inert gas source, notably a nitrogen source, such as to allow blowing of high pressure nitrogen through the burner and particularly through the nozzles to prevent liquid vitrifiable material to enter into the nozzles, solidify in, and hence plug, the burner. According to the exemplified embodiment, part of the burner length is enveloped by a cooling jacket 31, closed at both ends and comprising an inlet 32 connected to a source of cooling fluid, preferably water. The cooling jacket 31 extends over part of the length of the feeding tubes up to the burner head 11. The burner head 11 comprises a burner cap 33 defining a burner head space 35 between burner cap 33 and burner head 11. The burner head 11 further comprises through holes 37 connecting the jacket 31 with the burner head space 35. A cooling fluid feeding tube 39 extending essentially concentrically in the internal gas feeding tube 5 across the burner head 11 connects the burner head space 35 with a cooling fluid outlet connection 41. This arrangement allows for cooling of the gas feeding tubes as well as of the burner head by passing cooling fluid around and through the feeding tubes, and over, and axially through the burner head.

[0038] A submerged combustion burner as described here above is particularly suitable for a submerged combustion melter. A submerged combustion melter may comprise at least one submerged combustion burner as described. Preferably, at least two or more preferably at least three, at least four or at least five and/or less than 30, less than 25, less than 20, less than 18, less than 16, less than 14, less than 12 or less than 10 of such submerged burners are provided in the submerged combustion melter, depending on its dimensions, preferably at the bottom of the submerged combustion melter. It has been found that the burners allow for a reduced gas speed at which the combustion gases escape out of the burner head, with concomitant reduction of material velocities in the melt bath and hence reduced agitation in the melt bath. Furthermore, the arrangement of the burner nozzles laterally, on a peripheral envelope of the burner head reduces the risk of the burner being plugged with hardening or hardened melt in exceptional or extreme or transitional situations.

[0039] The burners may be arranged through a wall or preferably a bottom of a submerged combustion melter and fastened thereto by a mounting flange 45 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 47 in order to tightly fasten the burner 1 at a furnace bottom. The distance between the mounting flange 45 and the top of the burner cap 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.

[0040] A submerged combustion melter of the invention comprises a furnace 100 comprising a melting chamber 103 equipped with at least one burner as described, which contains a melt and communicates with an upper chamber 105 and a chimney for evacuation of fumes. The upper chamber 105 is equipped with baffles 107 that block upwards projection of any melt thrown from a surface of the melt by the agitation caused by the burner flames and/or gasses. 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. 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.

[0041] The melt may be withdrawn from the furnace chamber through a controllable outlet opening (not shown) located in the furnace chamber side wall, close to the furnace bottom essentially opposite a raw material feeder device 110.

[0042] 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.

[0043] If so desired, the furnace may be mounted on dampers which are designed to absorb vibrational movements.

[0044] 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.