Classifications

• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B5/00—Melting in furnaces; Furnaces so far as specially adapted for glass manufacture
  • C03B5/16—Special features of the melting process; Auxiliary means specially adapted for glass-melting furnaces
  • C03B5/235—Heating the glass
  • C03B5/2356—Submerged heating, e.g. by using heat pipes, hot gas or submerged combustion burners
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B5/00—Melting in furnaces; Furnaces so far as specially adapted for glass manufacture
  • C03B5/005—Melting in furnaces; Furnaces so far as specially adapted for glass manufacture of glass-forming waste materials
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B5/00—Melting in furnaces; Furnaces so far as specially adapted for glass manufacture
  • C03B5/02—Melting in furnaces; Furnaces so far as specially adapted for glass manufacture in electric furnaces, e.g. by dielectric heating
  • C03B5/027—Melting in furnaces; Furnaces so far as specially adapted for glass manufacture in electric furnaces, e.g. by dielectric heating by passing an electric current between electrodes immersed in the glass bath, i.e. by direct resistance heating
  • C03B5/03—Tank furnaces
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B5/00—Melting in furnaces; Furnaces so far as specially adapted for glass manufacture
  • C03B5/04—Melting in furnaces; Furnaces so far as specially adapted for glass manufacture in tank furnaces
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B5/00—Melting in furnaces; Furnaces so far as specially adapted for glass manufacture
  • C03B5/16—Special features of the melting process; Auxiliary means specially adapted for glass-melting furnaces
  • C03B5/20—Bridges, shoes, throats, or other devices for withholding dirt, foam, or batch
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B2211/00—Heating processes for glass melting in glass melting furnaces
  • C03B2211/20—Submerged gas heating
  • C03B2211/22—Submerged gas heating by direct combustion in the melt

Definitions

• the invention relates to a device and a method for melting vitrifiable materials, with a view to continuously supplying molten glass to glass forming installations,
• glass in the invention designates an essentially vitreous matrix , in particular made of mineral compositions designated under the term of glass or rock in the field of mineral insulation wool. More particularly targeted are installations for forming glass fibers of the mineral wool type for thermal or sound insulation.
• the invention also relates to installations for forming textile glass yarns known as reinforcing, for forming hollow glass of the bottle, flask type, or even flat glass installations such as float or laminating installations. In the latter case in particular, the actual fusion is generally to be completed by a refining step.
• Melting furnaces are generally classified in two main categories, in a conventional manner, according to the heating means adopted for melting the batch materials.
• this type of oven can be supplied, at least in part, with vitrifiable materials which are not raw materials from quarry or synthesized expressly for this purpose, but recycling products such as cullet, glass / plastic composites, or even hydrocarbon sources such as coal, organic polymers, which can be used as fuel for submerged burners.
• this mode of fusion has specificities. We tend to obtain a particular molten glass, of much lower density than that obtained with conventional ovens. We are dealing more with a foam than with a liquid phase, and generally much more viscous. Its treatment, its routing to forming members can therefore be delicate, and all the more so when the quantities of foam produced are significant.
• the object of the invention is therefore to provide a new method of melting vitrifiable materials, which may in particular allow more flexible, more flexible operation than that of conventional ovens. Incidentally, it seeks to ensure that this new mode of fusion can be integrated into existing installations using said conventional ovens.
• the invention firstly relates to a device for melting vitrifiable materials associating at least two separate melting modules, including: - a so-called A module, which is mainly equipped with heating means in the form of overhead burners and / or submerged electrodes.
• a module called B which is mainly equipped with heating means in the form of submerged burners.
• association means that they both contribute to producing vitrifiable materials in fusion, in different possible ways as will be detailed later.
• the module A according to the invention is therefore a conventional melting compartment, with electric melting (submerged electrodes) and / or with flames (overhead burners).
• the invention therefore makes it possible to conserve this type of melting compartment in existing industrial installations, and to derive all the benefits therefrom, particularly those of the experience accumulated thereon in the glass industry.
• a electric melting furnace when it is desired to significantly reduce the flight of certain compounds such as alkali borates.
• the module B uses a fusion by submerged burners.
• This concise term covers any mode of combustion of fuels, in particular fossils, with at least one oxidizing gas, said fuels / gases or the gaseous products resulting from combustion being injected below the level of the mass of vitrifiable materials.
• the burners can pass through the side walls or the bottom of module B. They can also be suspended from above, by hanging them on the roof or on any suitable superstructure. It is possible to choose to inject only these combustion gases through these burners, the combustions being carried out outside the melting module proper.
• the conventional fusion module A can be, concretely, the fusion module of existing forming installations.
• the invention can thus use these installations by modifying them, but without having to completely rebuild the oven. This is of vital economic interest, since the vast majority of existing installations in the glass industry have ovens of this type.
• the melting module B with submerged burners will be able to give the module A the flexibility it lacks, at different levels and without upsetting the rest of the installation.
• the invention makes it possible to use an already existing oven (module A) within the framework of a production different from that for which it was designed at the start, thanks to the addition of module B.
• the whole module A / module B actually forming a variable capacity oven.
• each conventional fusion module has "its" range of draw, and once its maximum draw is reached, one is blocked.
• the output from a submerged burner fusion module it can be modulated more easily, more quickly, with variations of relatively large amplitude.
• This fusion module B thus gives an additional flywheel compared to that of module A.
• the melting module B by submerged burners is capable of melting vitrifiable materials of changing composition and / or less "noble" than those used to supply conventional melting modules. We can therefore supply module B with batch materials whose chemical nature complements the batch materials feeding module A.
• - module B can be used to recycle materials which could deteriorate the operation of conventional type A melting modules, for example polluted cullet, composites glass / metal, glass / polymer composites or fuel polymers as mentioned above.
• conventional type A melting modules for example polluted cullet, composites glass / metal, glass / polymer composites or fuel polymers as mentioned above.
• the composition of the materials feeding the furnace B can be adapted, the part coming from recycling or reprocessing of waste / cullet being varied widely compared to the share of more traditional raw materials, coming from quarries in particular.
• modules A and B we have three cases, which each have their advantages depending on what we are looking for. Indeed, the invention can be applied to conventional fusion modules of existing production lines, and in this case the size of module A according to the invention is imposed at the start. This choice can also depend on the type or quantity of materials that you want to put in module B, in particular the quantity of cullet to be melted.
• the modules A and B can be of similar or even identical sizes, (considering the estimation of the size by the surface of the hearth and / or the volume defined by the module capable of being filled with glass in merger course).
• the module B can be of larger size than the module A, for example 1.5 times, at least twice or three times larger (for example in a size ratio ranging from 1, 1/1 at 30/1 or 20/1). This will be in particular the configuration chosen when it is envisaged to melt via module B a (very) large quantity of cullet or other materials suitable for this type of fusion.
• the relative dimensions of the melting modules A and B so that the module B is, by volume and / or bottom surface, at least one and a half times, two or three times smaller than module A (for example in a 1/1, 1 to 1/30 or 1/20 ratio).
• a melting module with submerged burners can have a much larger pull, at comparable size, than a conventional melting module. This is one of its most important advantages.
• the fusion module A and the fusion module B both open, directly or via channels / compartments, in a mixing module called module C.
• the invention therefore provides in this variant for mix the two flows of molten vitrifiable materials from modules A and B in a module specially dedicated to this.
• This module is to be fitted / designed appropriately to obtain a single stream as homogeneous as possible at the output, knowing that the streams to be mixed have different characteristics and which may vary during the operation of the fusion device as a whole.
• module A which is liquid, of a given composition, which can be kept essentially constant or which can on the contrary vary considerably.
• module B which has rather the appearance of a foam, of a much lower density, of higher viscosity, which can have a quite different temperature, and whose chemical composition may differ significantly from the previous one. This is the reason why it is recommended to equip this mixing module C with different means of agitation, homogenization and / or heating.
• this mixing module opens, directly or through at least one compartment, into a channel coming to feed fiberizing members (in particular with a view to producing mineral wool) or into a refining compartment (s 'it's about making flat glass).
• this channel is advantageously fitted, at the inlet and at the outlet, with a groove and / or weir system.
• the terms "inlet” and “outlet” are to be considered according to the direction of flow of the molten materials from A, B to C, from upstream to downstream of the production line.
• provision is advantageously made at the junction between module A and module C and / or between module B and module C a groove and / or weir system.
• it is advantageous to equip it (s) with thermal conditioning means.
• They may be heating means of the overhead burner type, immersed electrodes, which can be associated with cooling means such as air inlets or water box systems.
• This thermal conditioning can be used to facilitate / prepare the homogenization work which takes place in the mixing module C, to already bring the temperatures and viscosities of the streams of molten materials coming from the modules A and B closer together.
• An advantageous embodiment consists in that the module A communicates (without elevation), with the module C by a groove with resurgence, because this is often the configuration encountered in existing conventional installations. It can be associated with a module B which can be raised relative to the module C, for example with a discharge controlled by a groove and an appropriate lip. According to a second variant of the invention, provision can be made, in the case where the module A essentially works with overhead burners, that the module B opens, directly or via one or more channels, in the fusion module A, in particular in its downstream part. In this variant, there is therefore no longer strictly speaking a mixing module, and the foam from module B is poured into the molten glass of module A.
• module A It is then useful to provide the downstream part of module A where this spill is carried out by means of stirring, homogenization, of the bubbler type, or even submerged burners located in this zone, to facilitate the mixing of the two glasses (this zone is preferably located in the most downstream third of the module AT).
• a specific mixing module C for example by introducing the sparkling glass from module B into the channel into which the module A opens and which can supply the fiberizing members.
• the sparkling glass it is advantageous for the sparkling glass to be introduced, in particular by still pouring, into the upstream part of this channel, so that it has time, while walking on a significant length of this channel, to refine at best by coalescence of the bubbles which it contains, and which are generally of large size.
• the module B and the mixing module C of the first variant are confused: the conventional fusion module A is connected (directly or through at least one channel) to a mixing / fusion module B 'which is equipped with heating means essentially in the form of at least one submerged burner, and which is directly supplied with vitrifiable materials / cullet.
• This module B ′ then leads, directly or not, to a supply channel of fiberizing machines or to a refining compartment.
• This configuration is particularly advantageous when the module B is supplied with materials which are not likely to generate undesirable as in the case of cullet. In this case, it was found that the assembly could operate with temperatures significantly lower than if the same production was carried out in an oven with submerged electrodes. This provides a significant advantage in that the refractories of the furnaces wear out less quickly and pollute the glass produced less.
• the fusion module B opens into the fusion module A in the last third of its length, in particular by a gravity discharge system.
• upstream and downstream refer to the general direction of flow of the batch materials, from their placement in the melting compartments until their arrival, in the molten state, in the fiberizing bodies, and / or in the refining compartment if provided.
• the invention also relates to the method of implementing the melting device described above.
• a very interesting point of the invention is that each of the melting modules A and B can be supplied with different batch materials in different quantity and / or chemical compositions and / or different origins.
• the melting module B it is possible to supply the melting module B with cullet which may be polluted, which may come from the industry of flat glass or hollow glass for example.
• hydrocarbon-type fuels liquid or solid, such as residues from the petroleum industry, or from organic polymers, heavy fuel oil, coal. All the organic matter also introduced provides at least part of the fuel necessary for the submerged burners. Fusion by submerged burners thus has the advantage of being able to "digest" a lot of recycling products, a lot of waste, which is less true, at least in much smaller proportions, for conventional fusion modules of type A.
• the invention thus makes it possible to advantageously recycle inexpensive materials (even free or at negative cost like some of the waste mentioned above), which makes it possible to lower the overall cost of the raw materials of the installation.
• the melting module B with raw materials, in particular from quarries, or supplied by the chemical industry, or adopt any intermediate solution where the materials used to supply the module B are for part of the noble raw materials from quarries in particular and part of the waste / materials to be recycled.
• a raw material carrying silica it may be sand.
• a raw material carrying alkaline earth oxides it may be limestone, dolomite.
• a raw material carrying boron oxide it may be borax.
• a raw material carrying Na 2 O it may be sodium carbonate.
• alumina-bearing raw material it may be feldspar. Cullet can be added, preferably in moderate proportions.
• the method of implementing the device according to the invention may consist in operating the fusion modules A and B (or B ') jointly or alternatively. As seen above, it is thus possible constantly to regulate the operating regimes of the two modules, as a function of the desired overall draft or of the quantity or of the type of vitrifiable material or of the type of cullet which it is desired to use in the modules. A and B, or the type of final glass you want.
• the invention also relates to the use of this device or of its implementation process with a view to supplying meltable vitrifiable materials to the fiberizing members.
• They may be fiberizing members by internal centrifugation, or by external centrifugation or by mechanical and / or pneumatic drawing.
• the invention will be described in more detail using a non-limiting exemplary embodiment and the following figures:
• a preferred example according to the invention consists in adopting the installation, the principle of which is illustrated very diagrammatically in FIG. 1, namely: there is a conventional melting module 1, which is an electric oven known as a cold vault, using electrodes immersed there. In this type of oven, there is a bath of molten vitrifiable materials surmounted by a crust of vitrifiable materials which are not yet melted. The batching of the batch materials is done in a known manner by a conveyor belt or worm system. There is also a separate melting module 2 from module 1 and equipped with at least one submerged burner 8. The modules 1 and 2 open into the transfer channels 4, 5, themselves opening into a common mixing module 3 The arrows in the figure indicate the direction of flow of the glass throughout the installation. In particular for reasons of space, but also to favor the interpenetration and the mixing of the glass flows coming from modules 1 and 2, the inputs of said flows through the channels 4,5 into the mixing module 3 are made substantially perpendicularly. to one another.
• a conventional melting module 1 which is an electric
• modules 1, 3 and 2 can be arranged substantially in line successively, the glass then being removed from the module 3 along an axis, for example perpendicular to the previous one. It is also possible to arrange the modules 1 and 2 approximately side by side, the two streams of glass then arriving in a parallel or convergent manner in the mixing module 3.
• the module 3 is equipped with at least one submerged burner 9, and bubblers 7.
• the important point, in this zone, is to manage to mix these two glasses of densities, viscosity, and possibly of chemical compositions and different temperatures.
• the channels 4, 5 are equipped with thermal conditioning means, typically a combination of overhead burners and air inlets which can be opened / closed.
• thermal conditioning means typically a combination of overhead burners and air inlets which can be opened / closed.
• a single stream of glass leaves the module 3 to flow into the channel 6 (where a certain refining can take place, in the event that the glass still contains bubbles, in particular of large diameter, coming from the glass " sparkling wine ”from module 2).
• the channel then feeds fiberizing members, not shown, in a known manner.
• Figures 2, 3, 4 give some additional details on a possible configuration of the installation according to Figure 1. They remain schematic, and do not respect the scale for clarity.
• FIG. 2 is a top view: there is the electric melting module 1, the submerged burner module 2, the mixing module 3 and the channels 4,5 and 6.
• Figure 3 in section, shows how the glass from module 2 pours into the mixing module 3: there is a groove system, with the sole of module 2 raised relative to that of module 3. The glass then flows by pouring into the module 3 through the channel 5 which is quite narrow. There is therefore in fact a relatively narrow glass net which falls into the module 3, through a lip not shown.
• Figure 4 also in section, shows the configuration of modules 1, 3 and channel 6.
• the soles of modules 1 and 3 are (approximately) at the same level.
• the glass flows using a threshold 12.
• the height of the glass bath in the channel 6 is determined by another threshold 13 downstream of said channel 6 .
• a table 1 is given below grouping together the following data: A: the composition supplying module 1 with electric fusion, expressed in mass percentages of alumina, silica, alkalis, alkaline earth, boron in their oxidized form.
• composition B the percentage by mass of the rate of cullet relative to composition A with which the module 2 is supplied with fusion by submerged burners.
• Examples 1 to 4 therefore correspond respectively to the case where one has 0, 40, 60 and 80% cullet in the overall composition of the glass obtained.
• Example 1 at 0% of cullet corresponds to the case where module 2 with submerged burners is not supplied: only module 1 works, and the composition obtained therefore comes from 100% of raw materials supplying conventional module 1 It is thus possible to choose to have, at the outlet of channel 6, a glass of substantially constant composition, the level of cullet B chosen adjusting / supplementing composition A as appropriate.
• composition B of the cullet supplying the module 2 is for all the examples of substantially constant composition, composition which is as follows, in% by mass: SiO 2 71.5
• This cullet can also come from glazing provided with layers, of the metallic layer type, thin of the low emissive glazing type or solar control glazing, or thicker metallic layers as in the case of mirrors. Its composition is then modified accordingly.
• the cullet used to supply in these examples module 2 with submerged burners comes from the flat glass industry, in this case soda-lime-based base glass.
• soda-lime-based base glass soda-lime-based base glass.
• carrier materials carbonaceous fuels as seen above.
• Module A is a submerged electrode furnace supplied with conventional vitrifiable raw materials, in particular of the oxide, carbonate type, etc.
• the totality of the production of this module A is poured directly into an oven with submerged burners acting as module B also also supplied with cullet.
• the cullet supplied to module B represents 85% of the final glass flow.
• the final glass has the same composition as the final glass of Example 1. It can be seen that such a configuration works correctly and without producing undesirable, the electric oven being brought to 1100 ° C. and the oven with submerged burners being brought at 1150 ° C.
• the content of chromium (III) oxide in the final glass is 0.03% by mass, which indicates low wear of the refractories.
• the total energy consumption was 1200 kWh per tonne of glass.
• the same production with the same raw materials in a single electrode furnace requires a temperature of 1300 ° C., an energy consumption of 1250 kWh / t and leads to 0.1% by mass of chromium oxide in the final glass.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• Combustion & Propulsion (AREA)
• Glass Melting And Manufacturing (AREA)
• Processing Of Solid Wastes (AREA)
• Furnace Details (AREA)
• Feeding, Discharge, Calcimining, Fusing, And Gas-Generation Devices (AREA)
• Glass Compositions (AREA)

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