Patent Application
20200407257
This patent application discloses devices and methods of glass manufacturing, and more particularly, devices to extend the life of a glass melting chamber.
Glass manufacturing often occurs at high temperatures that require the equipment used in the glass manufacturing process to withstand harsh conditions. In particular, submerged combustion melting (“SCM”) is a specific type of glass manufacturing, in which an air-fuel or oxygen-fuel mixture is injected directly into a pool of molten glass. As combustion gases bubble through the molten glass, they create a high-heat transfer rate and turbulent mixing of the molten glass until it achieves a uniform composition. A typical submerged combustion melting chamber has a floor and a vertical burner passage extending through the floor. A burner positioned within the burner passage is submerged in the molten glass.
Not only does the burner, particularly at its top surface, experience high temperatures, but it also undergoes extreme temperature oscillations. These harsh conditions can lead to cracks and/or erosion forming in the burner, leakage, and the need for burner replacement and downtime of the melting chamber.
The present disclosure embodies a number of aspects that can be implemented separately from or in combination with each other.
In accordance with one aspect of the disclosure, there is a melting chamber including a chamber wall, a burner, and a cap. The chamber wall has a longitudinal axis and forms a passage having a passage axis transverse to the longitudinal axis. The chamber wall includes an inner wall surface with an inner wall edge extending about the passage. The burner is positioned in the passage and has a tubular body with a burner end spaced away from the inner wall edge so that a space exists between the burner end and the inner wall edge. The tubular body also has an outer burner diameter, an inner burner diameter, and a central conduit within the inner burner diameter. The cap is at least partially positioned in the space between the burner end and the inner wall edge. The outer cap surface also has an inner cap edge with a cap diameter that can be larger than, equal to, or less than the inner burner diameter of the hunter. The inner cap edge extends about the central conduit so that it forms a bore coaxially aligned with the passage.
In accordance with another aspect of the disclosure, there is a melting chamber including a chamber wall and a burner. Similar to the chamber wall discussed above, it has a longitudinal axis and forms a passage having a passage axis transverse to the longitudinal axis. The chamber wall includes an inner wall surface with an inner wall edge extending about the passage. Further, the chamber wall has a non-fluid-cooled portion and a fluid-cooled portion so that the non-fluid-cooled and fluid-cooled portions are disposed in two layers and contact each other at a boundary. The burner is positioned in the passage and has a tubular body with a burner end spaced away from the inner wall edge so that a space exists between the burner end and the inner wall edge. The tubular body has no coolant passage for a cooling fluid and has an outer burner diameter, an inner burner diameter, and a central conduit, within the inner burner diameter. The outer and inner burner diameters of the tubular body extend at least to the boundary of the non-fluid-cooled and fluid-cooled portions, and the central conduit may have a distal end that can be proximal the boundary of the non-fluid-cooled and fluid-cooled portions along the passage axis.
In accordance with yet another aspect of the disclosure, there is a melting chamber including a chamber wall and a burner. Similar to the chamber wall discussed above, it has a longitudinal axis and forms a passage having a passage axis transverse to the longitudinal axis. The chamber wall includes an inner wall surface with an inner wall edge extending about tire passage. The chamber wall has a non-fluid-cooled portion and a fluid-cooled portion so that the non-fluid-cooled and fluid-cooled portions are disposed in two layers and contact each other at a boundary. The burner is positioned in the passage and has a tubular body with a burner end spaced away from the inner wall edge so that a space exists between the burner end and the inner wall edge. The tubular body has no coolant passage for a cooling fluid and has an outer burner diameter, an inner burner diameter, and a central conduit within the inner burner diameter. The outer and inner burner diameters of the tubular body extend along the passage axis but do not extend along either of the non-fluid-cooled and fluid-cooled portions. The central conduit has a distal end that is distal to the outer and inner burner diameters.
The disclosure, together with additional objects, features, advantages and aspects thereof, will be best understood from the following description, the appended claims and the accompanying drawings, in which:
A general object of the present disclosure, in accordance with one aspect thereof, is to provide a burner of a melting chamber that has a longer lifespan and/or requires less maintenance than prior burners.
As briefly described in the background, harsh conditions within a melting chamber, particularly in SCM, can lead to burner cracking, erosion, and/or failure. Temperatures in the melting chamber can be several thousands of degrees Celsius (C) or Kelvin (K). A typical burner creates combustion gases by mixing a supply of oxidant with a supply of fuel. The combustion gases create bubbles in a molten material within the melting chamber that originate in the burner and detach in a cyclical manner. As relatively colder oxidant and fuel recirculates near a distal end and/or a top of the burner, the oxidant and/or the fuel lower the temperature near a distal end of the burner. As hot combustion gases recirculate near the distal end of the burner, they increase the temperature near the distal end of the burner. This recirculation of the oxidant, fuel, and combustion gases creates extreme temperature oscillations that happen continuously and in a very short amount of time. Each temperature oscillation can occur in one or less seconds, for example, in the range of 0.001 to 1.0 seconds, including all ranges, subranges, and values therebetween, in addition to the high temperatures experienced by the burner.
Over time, the distal end of the burner can fail due to these harsh conditions. The burners are often constructed from various materials, including metal, for example, stainless steel. Cracks form in the metal at the distal end. Once a crack forms, liquid, water, coolant, molten material, or the like can leak out of the burner. This leakage requires a burner to be repaired or replaced, which can be challenging if the melting chamber is currently housing the molten material. Such a repair or replacement may require draining all molten material and/or the melting chamber to be out of operation for a long period of time.
In order to protect and extend the useful lifetime of the burner in the melting chamber,
Below the inner wall surface 20, the chamber wall 12 also includes a non-fluid-cooled portion 24 having a first height 26 and a fluid-cooled portion 28 having a second height 30. The non-fluid-cooled and fluid-cooled portions 24, 28 are depicted as being disposed in two layers so that the non-fluid-cooled portion 24 is directly contacting the inner wall surface 20 and the fluid-cooled portion 28 is separated from the inner wall surface 20 by the non-fluid-cooled portion 24. The non-fluid-cooled and fluid-cooled portions 24, 28 directly contact each other at a boundary 32.
The non-fluid-cooled portion 24 can include a refractory material that can withstand the harsh environment in the melting chamber 10 because it is closer to and/or in direct contact with the molten material. Contrastingly, the fluid-cooled portion 28 can include metal and have voids for passing a cooling fluid because it is farther away from and/or not in direct contact with the molten material. The cooling fluid can protect other components in tire melting chamber 10, such as portions of the burners. In some aspects, the fluid-cooled portion 28 is positioned adjacent or closer to the atmosphere outside of the melting chamber 10 than the non-fluid-cooled portion 24.
A burner 34 is depicted in the passage 18. The burner 34 can have a tubular body 40 that extends between a proximal end 36 and a distal end 38. As used in this disclosure, “proximal” means farther away from the molten material and “distal” means closer to the molten material, relative to each oilier. The distal end 38 of the burner 34 is spaced away from the inner wall edge 22 so that a space 42 exists between the distal end 38 of the burner 34 and the inner wall edge 22. The space 42 can have various volumes. In one aspect, the space 42 at least 0.67″ deep, between the inner wall edge 22, and/or the inner wall surface 20, and the distal end 38 of the burner 34. If nothing fills the space 42, the molten material from the melting chamber 10 may at least partially fill the space 42. Additionally, the combustion gases can also at least partially occupy the space 42.
The tubular body 40 of the burner 34 also has an outer burner diameter 44, an inner burner diameter 46, and a central conduit 48 within the inner burner diameter 46. The outer and inner burner diameters 44, 46 can be outer and inner parts, respectively, of a tubular member of the burner 34. However, they could each also be separate tubular members from each other. The central conduit 48 can have a diameter that is smaller than the inner burner diameter 46, in order to fit within it, and it also has a distal end 50. The outer and inner burner diameters 44, 46 and the central conduit 48 can pass various oxidants and fuels through the burner 34 to create the combustion gases, which will be discussed in further detail below.
In particular in
In order to protect the burner 34, a cap 52 can be disposed in the space 42 distal the burner 34.
As seen in
The burner 34 in
Also seen in
In addition to the position of the cap 52, it can include a first material 80 that is the same or different with a second material 82 that is included in the chamber wall 12. By using the first material 80 with the higher durability, the cap 52 can further protect the area at the distal end 38 of the burner 34 from the harsh conditions of the melting chamber 10. However, the first material 80 can be costly and/or otherwise impractical fry other areas of the melting chamber 10, including the chamber wall 12. In one example, the first material 80 can be aluminum-zirconia-silica, silica, chrome, alumina, zirconia-mullite, mullite, platinum, ruthenium, rhodium, palladium, silver, osmium, iridium, gold, an alloy thereof, or the like. In some aspects, the cap 52 can be secured to the chamber wall 12 with a castable refractory material 83 between the chamber wall 12 and the cap 52 to fix and/or seal them together.
The cap 52 also has a cap interior 88 with a first cap diameter D1 and a second cap diameter D2. The first cap diameter D1 is disposed at the inner cap edge 58. The second cap diameter D2 is disposed along the passage axis PA so that the second cap diameter D2 is less than or equal to the first cap diameter D1. If the first and second cap diameters D1, D2 are equal, then the diameter of the cap interior 88 does not vary along the passage axis PA, and the cap 52 generally forms a hollow cylinder. However, if the first cap diameter D1 tapers so that the second cap diameter D2 is less than the first cap diameter D1, then the cap 52 forms a tapered cylinder (depicted in
The second cap diameter D2 and the length L can be selected based on the burner 34 and its dimensions. The overall height H can be selected based on the melting chamber 10 and its dimensions. In some aspects, the overall height H can be between 0 to the first height 26 of the non-fluid-cooled portion 24 of the chamber wall 12, including all ranges, subranges, and values therebetween.
The first cap diameter D1 and the second height 92 can be adjustable such that the first cap diameter D1 varies from being the same as the second cap diameter D2 to L and the second height 92 varies from 0 to the overall height H. In particular, the overall height H of the cap 52 can be substantially or approximately equal to or less than the first height 26 of the non-fluid-cooled portion 24 of the chamber wall 12.
As one advantage of using either the cap 52, as described herein, these components can be shaped to easily fit within the passage 18 no matter what the shape of the passage 18 or the burner 34. Thus, there would be no additional need to enlarge the passage 18 in order to accommodate either of the cap. Enlarging the passage 18 can cause unintended leaks to occur. These geometries make it easy to fit any type of passage 18 or burner 34 in the melting chamber 10.
As an additional or alternative advantage of the present disclosure, the cap 52 can have various geometries and designs that are independent from the burner 34. Because the two parts are not necessarily directly connected to each other, it is possible to use geometries and designs for the cap 52 and the burner 34 that are separate from one another, in addition to shapes of the cap 52, the burner 34 can have different orientations.
In
In this aspect, the distal end 150 of the central conduit 148 is proximal the boundary 132 of the non-fluid-cooled and fluid-cooled portions 124, 128 along the passage 118 so that the central conduit 148 extends along only the fluid-cooled portion 128 and not the non-fluid-cooled portion 124. In other words, the outer and inner burner diameters 144, 146 extend distal to the distal end 150 of the central conduit 148 along the passage 118. It is also possible to have the small gap or void (
In this aspect, the outer and inner burner diameters 144, 146 extend above the fluid-cooled portion 128 so that the cap 152 has a cutout volume and is shaped to accommodate the outer and inner burner diameters 144, 146. It is also possible for the components to be oriented such that tire outer and inner burner diameters 144, 146 extend along both of the non-fluid-cooled and fluid-cooled portions 124, 128 and not into the cutout volume of the cap 152. While the connection 178 and the oxidant and fuel inlets 174, 176 are similar to those in
Contrastingly in
In
Even though
For approximately 30% of the peaks, the temperature drops below the temperature of the molten material and, subsequently, it increases to a higher value than the temperature of the molten material, and, finally, it returns back to the temperature of the molten material before experiencing another peak. The net variation in the temperature of the approximately 30% of peaks is up to 1070 K.
In line 102 with the cap, the distal end 38 of the burner is now covered by the cap, being in the middle, bottom of the cap. The temperature depicted is always below the temperature of the molten material, 1673 K, and approximately 150 K below the temperature of the molten material. Further, the temperature of line 102 decreases steadily with time, over the approximately six seconds of data collected. While not wishing to be bound by any particular theory, the present inventors believe that the decrease in temperature below the temperature of the molten material depends on the first material 80 selected for the cap, and its thermal conductivity, and on any cooling from the burner, for example, with the coolant passages 64.
Additionally, there are no temperature peaks or oscillations in line 102. Therefore, the distal end 38 of the burner is always at a lower temperature, or cooler than, the temperature of the molten material and does not experience the temperature oscillations.
To better understand the temperature profile above the burner,
Because the inner wall edge 22 of the chamber wall can also experience significant wear and potential cracks,
As can be seen in
Both lines depict some temperature oscillations as the combustion gases pass by the respective edges 22, 58; however, the maximum temperatures, as well as the magnitude of the net variation in the temperature, when using the cap are lower compared to without the cap. Without the cap, the frequency of the peaks or oscillations at the inner wall edge 22 is approximately the same as the frequency of the peaks or oscillations at the distal end 38 of the burner, believed to be caused by the rapid change in flow pattern of combustion gases as the fuel and oxidant enter the burner, combust, and the gas bubbles move away from the burner. With the cap, the temperature oscillations are smaller; thus, protecting the chamber wall.
There thus has been disclosed a cap for melting chamber, that fully satisfies one or more of the objects and aims previously set forth. The disclosure has been presented in conjunction with several illustrative embodiments, and additional modifications and variations have been discussed. Other modifications and variations readily will suggest themselves to persons of ordinary skill in the art in view of the foregoing discussion. For example, the subject matter of each of the embodiments is hereby incorporated by reference into each of the other embodiments, for expedience. The disclosure is intended to embrace all such modifications and variations as fall within the spirit and broad scope of the appended claims.
