FR3106588A1 - Method and system for treating cullet fines in a glass melting unit - Google Patents

Abstract

Process and system for the treatment of cullet fines in a glass melting unit, applications to installations for the manufacture of packaging and float type glass, treatment of glass from a recycling sector and production of shaped objects glass. The invention relates to a method for treating cullet fines in a glass melting unit (1) comprising at least one melting furnace, the method comprising, within the unit, the following steps: i / upstream of the (des) smelting furnace (s), agglomeration by compression of cullet fines; ii / injection into the granule melting furnace (s) of the cullet fines obtained according to step i /. The invention also relates to an associated glass melting unit (1). Figure for the abstract: Fig. 1

Description

Process and system for processing cullet fines in a glass melting unit

The present invention relates to the field of glass melting, more particularly from cullet as vitrifiable raw material.

More particularly, the invention relates to the processing of cullet/glass fines in installations where the level of cullet in the raw materials is high.

The invention applies in particular to packaging glass manufacturing facilities, and to float-type facilities.

It also applies to facilities for processing glass from a recycling channel, which is recovered with a view to being recovered, and to facilities for the production of shaped glass objects. Among the shaped glass objects, mention may be made of all glassware intended for tableware or decoration, but also glass or glass-ceramic parts intended for household appliances, such as glass-ceramic cooking plates or glass portholes for washing machines.

By "cullet", also called "cullet", is meant in the context of the invention, the usual meaning, namely a scrap of glass which is the subject of recycling by reincorporation into the raw materials used for melting glass.

“Internal cullet” means cullet which is produced in a glass melting unit itself.

By “external cullet”, we mean cullet which comes from a chain of recovery and valorization of glass products.

By "fines" or "fines of glass", "fines of cullet", we mean in the context of the invention:

- the external cullet particles which are the fraction of waste produced during the upstream phases of collection, sorting of recyclable glass and preparation of the cullet and which is discarded either because the dimensions of the fraction are too small to be able to be sorted by automatic devices, particularly optical ones, i.e. the waste discarded during sorting itself;

• internal cullet particles that are generated during the granulation, grinding and transportation of this cullet;
• the internal cullet particles which are generated during the preheating/drying of cullet as vitrifiable raw material in a glass melting unit and whose particle size induces a flight of said particles during the preheating/drying;

• or a mixture of these inner and outer cullet particles.

Typically in the context of the invention, the fines considered have a particle size of less than 1 mm.

Cullet is made up of broken glass, which is traditionally added to vitrifiable raw materials (sand, soda ash, etc.) used to manufacture glass. Cullet is also used to promote vitrification.

The container glass industry uses several types of cullet:

• the so-called factory cullet which is produced internally between the furnace and the final packaging glass before shipping: its composition conforms to the glass produced and its reinjection rate is not critical with respect to the quality of the glass;
• the external cullet which comes from recovery and recycling: its composition is therefore variable. It must be analyzed and the chemical composition of the other raw materials must be adapted according to the rate of introduction of the external cullet.

Cullet is now an essential raw material for glassmakers and the main raw material for packaging glass manufacturers. Some melting furnaces operate at up to 95% cullet content. This is why the more the proportion of cullet in the fusion bed increases, the more it can be interesting to preheat it thanks to the recovery of the heat present in the fumes.

Glassmakers are constantly seeking to reduce their consumption of fossil fuels and lower their emissions. Increasing the cullet recycling rate is a good way to achieve this, since the material has already been vitrified, the fusion energy is lower.

During a study on the preheating of cullet, the inventors highlighted the risk of production and mixing of fine glass in the devices.

However, glass fines are problematic in the glass industry for two main reasons:

• their effect on health is harmful. In fact, glass dust can enter the body through the respiratory tract. Dangerous dusts are the finest that can reach the pulmonary alveoli and settle there. It is therefore necessary to limit their emission and their contact with the operators;
• their presence in a glass melting unit is currently problematic. Indeed, on the one hand, depending on the type of glass furnace, the glass fines can clog certain parts of the furnace, in particular the bottoms of the regenerator chambers and therefore reduce the productivity and the life of the furnace. On the other hand, the fines from the recycled glass are very loaded with organic matter which can disturb the chemistry of the furnace and the color of the glass produced.

Thus, glass/cullet fines, whether of internal or external origin, are currently undesirable for the glass industry and therefore not exploited.

There is therefore a need to improve glass melting units, in particular in order to overcome the aforementioned drawbacks of glass fines/cullet.

To do this, the invention relates, in one of its aspects, to a method for treating cullet fines in a glass melting unit comprising at least one melting furnace, the method comprising, within the unit , the following steps:

i/ upstream of the melting furnace(s), agglomeration by compression of cullet fines;

ii/ injection into the melting furnace(s) of the granules of cullet fines obtained according to stage i/.

According to an advantageous variant, step i/ comprises the following sub-steps:

i1/ mixture of cullet fines with a mineral additive;

i2/ pressure agglomeration of the mixture according to sub-step i1/.

Preferably, sub-step i1/ is carried out with a quantity of mineral adjuvant of between 1 and 20% of the mixture.

According to an advantageous embodiment, the cullet fines agglomerated according to step i/ being at least partly internal cullet fines, the method comprises a step for recovering the fines emitted during the preheating/drying of cullet to be baked as as charge of vitrifiable material in the melting furnace(s).

According to another advantageous embodiment, the method comprises a step of preheating/drying cullet to be charged as part of the charge of vitrifiable material in the melting furnace(s), consisting of direct contact between the cullet and clean hot air being either that coming from the exit fumes from the melting furnace(s) having undergone treatment, or that heated by the exit fumes from the melting furnace(s) by through an air/air exchanger.

The invention also relates to a glass melting unit, intended to implement the method described above, comprising:

- at least one melting furnace,

- at least one agglomeration system by compression of cullet fines, connected downstream to the melting furnace(s) to supply the latter with granules of cullet fines as part of the charge of vitrifiable material.

According to an advantageous embodiment, the agglomeration system comprises:

- a mixer-distributor suitable for mixing cullet fines with a mineral adjuvant and distributing the mixture obtained downstream,

- a press operating by compression, connected upstream to the mixer-distributor, to produce granules of the mixture obtained under pressure.

Advantageously, the press is a so-called tangent wheel press.

According to another advantageous embodiment, the unit further comprises:

- at least one heating device adapted to be powered by cold cullet,

- a suction system adapted to suck the atmosphere from the heating equipment, the suction system comprising at least one bag filter adapted to capture the cullet fines generated within the heating equipment.

- at least one means of collection and transport of cullet fines captured adapted to collect and bring them to the input of the agglomeration system.

According to an advantageous embodiment, the heating equipment is a rotating furnace. Alternatively, the heating equipment can be a fluidized bed dryer or a heated helical elevator

Preferably, the heating equipment is adapted to operate with hot air against the flow of cold cullet.

According to an advantageous variant, the suction system comprises a cyclone arranged between the heating equipment and the bag filter.

According to a first embodiment, containers are provided as collection and transport means to be moved individually from the outlet of the bag filter to the inlet of the agglomeration system.

According to a second embodiment, provision is made, as collection and transport means, at least one conveyor for continuously bringing the cullet fines collected from the outlet of the bag filter to the inlet of the agglomeration system .

According to an advantageous embodiment, the unit comprises a line for supplying the heating equipment with clean hot air, heated by the heat of the fumes leaving the melting furnace(s).

According to a first advantageous variant embodiment, there is provided a system for processing the fumes leaving the melting furnace(s), and the supply line directly connects the outlet line of the fumes processing system to the interior of heating equipment.

Advantageously, the flue gas treatment system comprises:

- at least one outlet flue gas cleaning reactor in which the flue gases are brought into contact with at least one reagent with respect to the pollutant,

- at least one electrofilter connected to the outlet of the cleaning reactor.

According to a second advantageous variant embodiment, an air/air exchanger is provided, one of the circuits of which is that of the outlet fumes from the melting furnace and the other is part of the clean hot air supply line.

The invention finally relates to an installation for the manufacture of packaging glass or an installation of the float type, or an installation for processing glass from a recycling sector or an installation for the production of shaped glass objects, comprising at least one glass melting unit as previously described

The invention therefore essentially consists in granulating cullet fines within a unit itself, which may come from an external cullet or be produced internally during the drying of the cold cullet, and this preferably by achieving optimum thermal integration by preheating the cold cullet without contact by the heat of the fumes leaving the melting furnace(s).

In fact, by judiciously selecting a type of apparatus for preheating the cullet by the heat resulting from the fumes leaving the furnace(s) within a glass melting unit, the inventors were confronted with a risk significant production and mixing of glass fines by these devices. They then sought not to dispose of these internal cullet fines, as glassmakers did until now, who postulate that glass fines are harmful for glass melting processes, but to recycle them.

They then judiciously thought of carrying out an aspiration for a collection then for a granulation by compression, directly usable as vitrifiable raw material injected at the inlet of the unit, with the possibility of injecting in addition to or instead of fines of external cullet.

The invention brings many advantages among which we can mention:

• an economically viable implementation process and system: the investment costs linked to the installation and maintenance of the various components, whether for the agglomeration of cullet fines, the cullet preheating and the recovery and collection of internal cullet fines, quickly pay for themselves;
• the various components of the systems according to the invention can be installed, tested in parallel with production and then be integrated into the production unit, minimizing production stoppages. Stops for integration into an existing melting unit are therefore limited. In addition, installation can also be carried out in units currently in place during maintenance shutdowns, for example. This greatly limits the impact on the overall operation of a glass production plant;
• the possibility of raising the temperature solely thanks to the heat from the fumes of the melting furnace, all of the cullet fines at a temperature of 250°C, which makes it possible to rid them of part of their material content organic;
• the heat recovery from the fumes leaving the furnace to preheat the cold cullet and maintain the temperatures of the granules of fines before their injection into a melting furnace, directly leads to a saving on the consumption of fossil energy of said furnace and on the reduction in CO ₂ emissions and gaseous discharges.

Other advantages and characteristics of the invention will emerge better on reading the detailed description of examples of implementation of the invention given by way of illustration and not limitation with reference to the following figures.

FIG. 1 is a general block diagram of a method for treating cullet and fines according to the invention with the circulation of gases and solids in a glass melting unit.

FIG. 2 is a partial synoptic view of a glass melting unit incorporating a system for processing cullet fines according to a first mode of the invention.

FIG. 3 a partial synoptic view of a glass furnace incorporating a system for processing cullet fines according to a second mode of the invention.

detailed description

Throughout this application, the terms "upstream", "downstream", "input", "output" are to be understood by reference to the direction of circulation of gases and solids in a glass melting unit putting implement a system according to the invention.

It is also specified that the reference letters A, B, C and D in figures 2 and 3 indicate the correspondences in the lines of air circulation.

For the sake of clarity, an element common to the embodiments of FIGS. 2 and 3 is designated by the same reference numeral.

There is shown in Figure 1, the different steps implemented in the process according to the invention, with the circulation of gases and solids in an existing glass melting unit.

The method according to the invention can therefore be advantageously implemented in parallel with the production of an already existing melting unit.

There is shown in Figures 2 and 3 a first and a second embodiment of a method according to the invention implemented within a glass melting unit 1 from cold cullet as main vitrifiable raw material .

• By way of indication, in order to characterize and size the various components of the process according to the invention, the inventors assumed the following input data: possible consumption of cullet: 450 t/d;
• throughput of cullet to be preheated: 225 t/d;
• moisture content of the cullet: 2 to 6%;
• grain size of the vitrifiable material particles entering the melting furnace: 0 to 40 mm;
• melting furnace outlet flue gas temperature available: 400°C or 500°C;
• flue gas flow rate available: 30,000 Nm ³ /h;
• desired cullet temperature at the entrance to the melting furnace: 250°C.

To exploit the cullet fines seen to date as unusable by the glass industry, the inventors have thought of carrying out an agglomeration by compression of the cullet fines at the inlet of the melting unit 1, whether they are of origin external or internal and therefore recovered as explained below.

The essential advantages of a compression agglomeration is that it does not use a liquid binder and that the resulting granules are extremely resistant to breakage and abrasion with significant compaction due to high external pressure. .

System 2 which implements agglomeration by compression at the inlet of the melting furnace includes:

- a mixer-distributor 20 suitable for mixing the cullet fines with a mineral adjuvant and distributing the mixture obtained downstream,

- A so-called tangent-wheel press 21, connected upstream to the mixer-distributor, to produce granules of the mixture obtained under pressure.

Typically, a press with tangent wheels 21 makes it possible to produce granules (also called tablets) of the order of 3 to 4 cm.

As illustrated, an adjuvant selected from sodium silicate, sodium carbonate, kaolin or a mixture thereof is introduced into the mixer-distributor 20 and 21 with the cullet fines. The amount of adjuvant introduced is preferably between 1 and 20% of the mixture. The mixer-distributor 20 enables intimate mixing between the glass fines and the mineral additive.

In the context of the invention, the inventors have set a limit greater than 1 mm to the sizes of fines to be granulated whether they come from external or internal cullet, and this for several reasons. On the one hand, in the event of the presence of infusible particles in the fines, a size of less than 1 mm allows them to dissolve and therefore not to create a problem of poor quality of glass downstream. On the other hand, a size limited to 1 mm guarantees protection against wear of the components (frets) of the tangent wheels of the press 21.

Depending on the specificities of the mixer 20 and/or the press 21, and/or the installation constraints on site, a bucket-type elevator 22 can be arranged at the outlet of the mixer 20.

This bucket elevator 22 can thus bring the mixed particles into a first silo 23 upstream of the press 21.

The granules formed by the press 21 fall by gravity into a second silo 24, suitable for the distribution of granules.

A conveyor of the belt conveyor type 3 makes it possible to bring the granules distributed by the second silo 24 into a circuit for supplying raw materials to one or more melting furnaces, not shown, of unit 1.

The belt conveyor 3 can advantageously use high temperature rubber belts or textile belts. The choice of the type of strips can be made according to several criteria, such as the space available in the existing installation, the return on investment expected for the system according to the invention and the temperature objective of the glass mixture at the inlet. in the melting furnace(s).

Typically, high temperature rubber belts can accept maximum product temperatures of 200°C continuously and 400°C peak. Textile belts can withstand temperatures up to 400°C.

As an indication, with the cullet inlet rate of 225 t/d to be preheated to 250°C, the cullet temperature at the inlet to the melting furnace can be less than 200°C, which makes it possible to envisage a conveyor 3 with high temperature rubber bands.

Typically, the hot air C/, recovered as explained below and sent as the atmosphere of the conveyor 3 can be at 250°C.

Another aspect of the invention will now be described, namely the treatment of the fumes leaving the furnace or furnaces of unit 1, and of the cold cullet from the heat and/or the clean hot air recovered at the exit of the fumes from the melting furnace, as well as the recovery of cullet fines produced during this treatment before their reinjection into the system 2 according to the invention.

In accordance with the invention, the cold cullet at the inlet of unit 1 is preheated by direct contact with hot air A/ originating either from clean outlet fumes (FIG. 2) or from air heated by the outlet fumes within a heat exchanger 48 of the air/air type (FIG. 3).

In the embodiment of FIG. 2, the flue gas treatment system 4 comprises, upstream of the chimney 40, a reactor 41 for cleaning the outlet flue gases within which the flue gases are brought into contact with at least one reagent vis- vis-a-vis the pollutant, injected upstream of the reactor, an electrofilter 42 connected to the outlet of the cleaning reactor as well as a plurality of suction pumps 43, 44, 45 respectively to ensure the hot air at different temperatures necessary for the needs of cold cullet processing and extraction through the chimney.

Typically, for outlet fumes at approximately 480° C., the hot air A/ intended to be sent directly for the preheating of the cullet via the injection line 5, and which is sucked directly at the outlet of the electrofilter 42 maybe around 400°C.

The hot air C/ at the lowered temperature compared to the hot air A/, intended to be sent as the atmosphere of the belt conveyor 3, is typically at 250°C.

A bypass line 47 can be provided to deflect, if necessary, fumes from the oven outlet and bring them directly to the chimney 40 without passing through the system 4 for treating the fumes. This bypass line 47 can be put into service in particular in the event of a fault in the treatment system 4 .

In the embodiment of Figure 3, the fumes from the oven enter an exchanger 48 of the air-air type and therefore heat the line 5 of the clean air circuit, which is the hot air supply line A / intended to be sent directly for the preheating of cullet.

The exchanger 48 is preferably equipped with an automatic unclogging device on the outlet flue gas circuit.

System 6 for processing cold cullet, operating in parallel with system 2 for agglomeration of cullet fines, comprises a rotary kiln 60.

In the rotating drum of this furnace 60, the cold cullet is dried directly by the injection of the hot air flow A/ at around 400°C, preferably against the current. While preheating, the cullet follows the movement of the kiln dryer tube, being stirred and gradually advancing towards the exit.

As an indication, with the input data mentioned above, the characteristics of the rotary kiln 60 are as follows:

• cullet throughput: 9.4 t/h;
• cullet inlet temperature: 20°C;
• cullet outlet temperature: 270°C;
• hot air flow A/ injected: 12,200 Nm /h
• inlet hot air temperature: approximately 400°C
• outlet hot air temperature: approximately 120°C

It can be seen that the flow of hot air necessary for preheating the cullet is significantly lower than the flow of fumes leaving the melting furnace(s), available in unit 1.

The rotary kiln 60 is adapted to continuously evacuate the water vapor which is released during the preheating of the cullet.

The rotary furnace 60 is connected downstream to a silo 61 which makes it possible to feed the belt conveyor 3 by gravity in order to feed the raw material supply circuit of the melting furnace(s), not shown, of unit 1.

The hot cullet distribution silo 61 is preferably insulated to conserve the stored heat.

Depending on the specifics of the rotary kiln 60, and in particular its weight, and/or on-site installation constraints, a bucket-type elevator 62 can be arranged at the outlet of the rotary kiln.

This bucket elevator 62 can thus bring the hot cullet directly to the top of the silo 61 distributor.

Mixing the cold cullet in the rotary kiln is likely to produce a significant amount of cullet fines.

To recover them, a suction system 7 is directly connected inside the rotary furnace 60 and preferably at all points generating a mixing of the glass fines, such as for example in the atmosphere of the belt conveyor 3, or at inside the silos 23, 24, cullet particles or granules obtained by the agglomeration system 2 or inside the cullet silo 61, or even at the outlet of the bucket elevators 62.

The suction system 7 comprises a bag filter 70 connected to a suction pump 72 downstream.

Preferably, a cyclone 71 is arranged in the suction line of the flow B/, between the rotary kiln 6 and the bag filter 70.

Thanks to such a system 7, the atmosphere B/ of the rotary kiln 60, which at its outlet has reached a temperature typically of 200° C., is directly sucked up and treated by the bag filter 70, in order to collect the glass fines/ cullet produced by mixing in furnace 60.

The cyclone 71 advantageously makes it possible to recover the larger fines before the sleeve filter 70 and thereby avoid damaging the sleeves of the filter 70 and achieve a targeted particle size in the filter 70.

The collection of glass/cullet fines at the outlet of bag filter 70 can advantageously be carried out by flexible containers of the big-bag type 8.1, 8.2 which are easily found in industry and which can be moved easily by example on carts or other wheeled platforms.

The replacement of the full containers 8.1, 8.2 can be done easily and almost in real time, i.e. without introducing any discontinuity in the process. Thus, as illustrated, when a first flexible container 8.1 is filled by the collection of cullet fines at the outlet of the bag filter 70, a second container 8.2, which is already full, can be emptied simultaneously into the mixer-distributor 20.

It is also possible to envisage collecting and reinjecting the cullet at the outlet of the cyclone 71. The collection can also be carried out by means of flexible containers 8.3 of the big-bag type. The cullet typically collected at a diameter of the order of a millimeter can advantageously be recycled, that is to say reinjected into the cold cullet at the inlet of the rotary kiln 60.

In order to further guarantee the recovery of the cullet fines, as illustrated, it is also possible to envisage connecting the atmosphere of the belt conveyor 3, directly at its outlet, with the suction line of the system 7. This is illustrated by the flow D/ in figures 2 and 3.

In the embodiment of FIG. 3, the suction line of the cullet fine collection system 7 advantageously constitutes the clean air inlet line of the air-air exchanger 48 which therefore supplies the furnace in return. turning 60. There is therefore an air/cullet fines brewed and collected circulation system which is in a closed circuit.

In this mode, as illustrated, a fresh air inlet is advantageously provided at the outlet of the bag filter 70. This makes it possible to mix this fresh air with the hot air which could have a high humidity rate (case of drying of cullet) and therefore in the end to lower the inlet temperature in the exchanger and to lower the humidity rate in the flow A / reinjected into the rotary kiln 60. The excess air being rejected via the silencer 51 .

A bifurcation line comprising a valve 50 can advantageously be provided in order to regulate the temperature of the flow A/. Thus if the temperature transmitter TT arranged downstream detects a temperature of the flow A/ which is too high, the valve 50 is opened in order to relieve the flow of hot air A/ through the silencer 51, until the air hot A/ sees its temperature drop to the temperature required for the process.

The invention is not limited to the examples which have just been described; it is in particular possible to combine together characteristics of the examples illustrated within variants not illustrated.

Other variants and improvements can be considered without departing from the scope of the invention.

If in the examples illustrated, the collection and conveying of internal cullet fines is done by means of flexible containers, of the big-bag type, which are moved individually, one can envisage continuous conveying between the outlet of the filter at sleeves and the entrance to the mixer-dispenser 20.

As regards the heat treatment of the cold cullet, it is possible to provide equipment in addition to or integrated into the rotary kiln which allows treatment at temperatures between 100 and 400° C. (pyrolysis) via a roasting treatment. This advantageously makes it possible to decompose the organic matter present in the dirty household cullet. Organic materials have the disadvantage of reducing the quality of the glass by the formation of color beads in the oven. Such a heat treatment would thus make it possible to increase the quality of the glass obtained downstream.

Claims (19)

Process for processing cullet fines in a glass melting unit (1) comprising at least one melting furnace, the process comprising, within the unit, the following steps:
i/ upstream of the melting furnace(s), agglomeration by compression of cullet fines;
ii/ injection into the melting furnace(s) of the granules of cullet fines obtained according to step i/. Processing method according to claim 1, step i/ comprising the following sub-steps:
i1/ mixture of cullet fines with a mineral additive;
i2/ pressure agglomeration of the mixture according to sub-step i1/. Treatment process according to claim 2, according to which sub-step i1/ is carried out with a quantity of mineral adjuvant of between 1 and 20% of the mixture. Treatment method according to one of the preceding claims, the cullet fines agglomerated according to step i/ being at least partly internal cullet fines, the method comprising a step for recovering the fines emitted during the preheating/drying of cullet to be charged as batch of vitrifiable material in the melting furnace(s). Treatment process according to one of the preceding claims, comprising a step of preheating/drying cullet to be charged as part of the charge of vitrifiable material in the melting furnace(s), consisting of direct contact between the cullet and clean hot air being either that coming from the outlet fumes of the melting furnace(s) having undergone treatment, or that heated by the outlet fumes of the melting furnace(s) through an air/air exchanger. Glass melting unit (1) comprising:
- at least one melting furnace,
- at least one system (2) for agglomeration by compression of cullet fines, connected downstream to the melting furnace(s) to supply the latter with granules of the cullet fines as part of the batch of vitrifiable material. A glass melting unit (1) according to claim 6, the agglomeration system comprising:
- a mixer-distributor (20) suitable for mixing the cullet fines with a mineral adjuvant and distributing the mixture obtained downstream,
- a press operating by compression, connected upstream to the mixer-distributor, to produce granules of the mixture obtained under pressure. Glass melting unit (1) according to claim 7, the press being a worm wheel press (21). Glass melting unit (1) according to one of claims 6 to 8, further comprising:
- at least one heating device (6) adapted to be supplied with cold cullet,
- a suction system (7) adapted to suck the atmosphere from the heating equipment, the suction system comprising at least one bag filter (70) adapted to capture cullet fines generated within the heating equipment,
- at least one means (8.1, 8.2) for collecting and transporting cullet fines captured adapted to collect and bring them to the input of the agglomeration system Glass melting unit (1) according to claim 9, the heating equipment being a rotary furnace. A glass melting unit (1) as claimed in claim 9 or 10, the heating equipment being adapted to operate with the hot air countercurrent to the flow of cold cullet. Glass melting unit (1) according to one of Claims 9 to 11, the suction system comprising a cyclone (71) arranged between the heating equipment and the bag filter. Glass melting unit (1) according to one of Claims 9 to 12, comprising as collection and transport means containers (8.1, 8.2) to be moved individually from the bag filter outlet to the entry to the agglomeration system. Glass melting unit (1) according to one of Claims 9 to 12, comprising, as collection and transport means, at least one conveyor for continuously supplying cullet fines collected from the outlet of the bag filter to at the entrance to the agglomeration system. Glass melting unit (1) according to one of Claims 9 to 14, comprising a supply line (5) of the heating equipment with clean hot air, heated by the heat of the fumes leaving the melting furnace(s). Glass melting unit (1) according to claim 15, comprising a system (4) for treating the fumes leaving the melting furnace(s), the supply line directly connecting the exit line of the flue gas treatment inside the heating equipment. Glass melting unit (1) according to claim 16, the flue gas treatment system comprising:
- at least one outlet flue gas cleaning reactor (41) in which the flue gases are brought into contact with at least one reagent with respect to the pollutant,
- at least one electrofilter (42) connected to the outlet of the cleaning reactor. Glass melting unit according to claim 15, comprising an air/air exchanger (48) one of whose circuits is that of the fumes leaving the melting furnace and the other is part of the supply line (5) in clean hot air. Installation for the manufacture of packaging glass or installation of the float type or installation for processing glass from a recycling sector or installation for the production of shaped glass objects, comprising at least one glass melting unit (1) according one of claims 6 to 18.