WO2012130725A1

WO2012130725A1 - Melting device

Info

Publication number: WO2012130725A1
Application number: PCT/EP2012/055108
Authority: WO
Inventors: Martin Demuth; Burkhardt Holleis; Gyula PALMAI; Michael Potesser; Davor Spoljaric
Original assignee: Messer Hungarogaz Kft.; Messer Austria Gmbh
Priority date: 2011-03-25
Filing date: 2012-03-22
Publication date: 2012-10-04
Also published as: DE102011014996A1; EP2688846A1; CN103562148A

Abstract

A melting device comprises a burner arrangement (8) comprising a number of burners (12, 13, 14), which are arranged on a side wall (9) of a melter (2) and from which fuel gases are respectively discharged at a predetermined angle onto the material (5) to be melted in such a way as to form a number of zones of differing heat input. Used with preference for this are flamelessly operating burners and/or mixed air/oxygen burners (12, 13, 14), in which the proportion of oxygen in the supplied oxidizing agent can be controlled in dependence on parameters that are measured in the melter (2). The device according to the invention is particularly suitable for producing ceramic frits and is distinguished by a high degree of cost-effectiveness and low NO_x values in the exhaust gas.

Description

melter

The invention relates to a melting apparatus, in particular a melting apparatus for melting non-metallic materials, such as ceramic frit.

Devices for melting non-metallic materials such as frit,

Ceramics, glass or basalt are known per se. These usually have a melting tank and a plurality of burners whose burner flames are directed during operation into the interior of the melting tank. The associated burners are usually operated with fossil fuels, mostly natural gas or oil. To maintain the combustion, an oxidizing agent is supplied, which is usually air, but in newer plants increasingly but also pure oxygen. In so-called regenerative burners preheated air is supplied through the outlet openings in the furnace wall the furnace interior.

EP 2 030 953 A1 describes a method and an apparatus for melting glass in which a glass batch is fed via an inlet region of a glass melting tank. Subsequently, the glass is replaced by the

Heat input of several burners melted. The molten material passes through a refining zone and a Abstehbereich, within which also takes place a supply of heat energy by means of burners. In the refining area, the burners will operate in such a way that flameless combustion takes place. The flameless combustion produces a much more even heat distribution in the

Glass melting furnace. In this way, the glass melting furnace more energy can be supplied, since the temperature of the "hotspots", so the places with

Temperature maxima, lower than an otherwise comparable

Burning with a bright flame, which in particular the thermal load on the walls of the melting furnace is substantially reduced. In addition, the flameless combustion leads to low NO _x concentrations in the exhaust gas. The object of the invention is to increase the cost-effectiveness of melting non-metallic materials and the NO _x pollution of the exhaust gas

To reduce objects of the prior art.

The object is achieved by a melting device having the features of patent claim 1.

The melting device according to the invention comprises a melting tank, which has an entry region for the material to be melted, a discharge channel for

molten material and arranged in a wall opposite the entry area wall burner assembly having a plurality of burners arranged in a burner, wherein at least two burners of

Burner assembly are set so different angularly that at least two zones with on the surface of the melted Guts

result in different heat.

The invention is based on a melting furnace in the form of a substantially horizontally arranged trough (melting tank), at least over most of its longitudinal extent of the material to be melted (im

Following is "good"), starting from an entry region, which is arranged in the region of a front side of the melting tank and typically comprises entry openings for supplying the material to be melted, wherein the entry openings in the front side itself and / or in the front side adjacent portions of a side wall In solid form, for example as a granulate fed Good is in a the

Entry area melted adjacent melting zone and into one

flowable state brought. It then flows through the melting tank in the direction of the discharge channel, which is usually in the area of the

Inlet opening / en opposite end face of the melting tank is arranged in the bottom region. The transport of the product through the melting tank preferably takes place in that the molten material flows under the action of gravity in the direction of the discharge channel; For this purpose, the melting tank can have a bottom sloping down to the discharge channel. The Melted good is then via the discharge channel of the other

Processing supplied.

The heating of the material to be melted is carried out at least substantially by means of a burner arrangement which is located on an entry area for the

Good to be melted opposite wall, preferably above the

Ableitungskanals, is arranged. Further burners, in particular arranged in the manner of a cross-firing furnace laterally to the intended direction of flow of the goods burners are not required in the invention, but nevertheless not excluded. The burner assembly comprises a plurality of burners received in a burner stone or in separate burner bricks, which are set at an angle so that the fuel gases flowing out of them impinge on the surface of the product. The angles by which the burners are each employed depend on the geometry of the melting tank; However, at least two burners on different angular positions, so that different areas of the surface of the Guts charged with fuel gases and thus different zones of heat input are created. A relative to the horizontal flatter angular position is provided for one or more burners, which act on a region adjacent to the entry area of the material surface to create in this area a melting zone for melting the registered Guts. One or more burners with one opposite the above

Burner steeper angular position relative to the horizontal serves / serve to keep the already molten material in a "warming zone" at a predetermined temperature and / or viscosity in the liquid state

Warming zone is thus between the melting zone and the discharge channel. In the context of the invention, additional functional zones may additionally be present within the melt and be subjected to heat by means of a burner arranged at an angle correspondingly, for example a refining zone. In the discharge channel or in the area of subsequent transport or processing stages so-called "feeder burners" can be provided in a manner known per se, which keep the outflowing strand of the liquefied material at a predetermined temperature and / or viscosity. The number, power (s) and angle (s) of the burners is the

Circumstances, in particular the geometric conditions of the melting tank and the respective melting task adapted accordingly. For example, a compact device comprises three burners mounted in a burner assembly located in a side wall opposite the entry region

Melting wall is arranged. Of these burners at least two burners are provided for melting the goods and with respect to the

Horizontal acute angles of, for example, 5 ° to 10 ° are mounted in the burner assembly. The angle is such that the fuel gases passing from these burners onto the surface of the material in here as a melting zone

designated, impinge the entry zone adjacent area and cause there the melting of the registered Guts. The third burner is used for

Maintaining a certain temperature within the already liquefied melt in a holding zone between the melting zone and the

Drain channel is located. This third burner thus has a steeper angle of attack of, for example, 20 ° to 45 ° relative to the horizontal, compared with the two other burners, and generally has a lower maximum power than the aforementioned burners. Larger arrangements have a burner arrangement with more than three burners for the aforementioned or other purposes.

The burners of the device according to the invention preferably operate with liquid or gaseous fuels such as oil, propane, natural gas or others

Hydrocarbons and an oxygen-containing gas as an oxidizing agent.

The oxidizing agent is preferably an oxygen-rich gas, ie a gas with an oxygen concentration which is greater than that of air, for example with an oxygen concentration of more than 25% by volume, preferably more than 40% by volume, especially preferably more than 90% by volume O ₂ .

Compared to prior art melters, the inventive arrangement provides a high yield of molten material with a comparatively small fuel consumption and small footprint, thus high efficiency, low energy consumption and a low NO _x concentration in the exhaust gas. The melting device according to the invention is particularly suitable for Melting non-metallic materials, in particular glass, ceramic frit or basalt.

An advantageous development of the invention provides that the angular position of at least one burner is adjustable. In this way, the setting of the burner in the burner assembly of the respective melting task can be adjusted or optimized. For example, the angular position of each burner - even during operation - can be adjusted continuously;

A preferred embodiment of the invention is characterized in that the power of at least one burner in dependence on parameters measured in the melting tank, such as the temperature or the

Composition of the atmosphere in the melting tank or the temperature or viscosity of the melt, is controllable. The control is preferably carried out zone-dependent, i. the power of the burners acting on one zone can be regulated independently of the power of the burners acting on the other zone (s).

Preferably, at least one of the burners of the burner arrangement can be operated with oxygen as oxidizing agent. The use of oxygen burners increases the efficiency and significantly reduces the proportion of nitrogen oxides compared to burners that use air as the oxidant. As "oxygen" is meant here a gas whose oxygen content is at least 95 vol .-%, preferably at least 99 vol .-%.

Alternatively or additionally, in one of the burners of the burner arrangement, it can be advantageous to use an air / oxygen mixed burner in which the oxygen proportion of the oxidant fed can be adjusted, preferably in the entire range between 21% by volume, the oxygen content in air, and 100 % by volume. The higher the oxygen content of the oxidizing agent, the higher the temperature of the flame can be set. An example of such a burner is known from WO 2008 092 763 A1. Advantageously, the oxygen content of the oxidizing agent supplied to the air / oxygen mixing burner may vary depending on the melting tank

be measured measured parameters. The burner should be there

expediently allow a stepless as possible adjustment of the oxygen content in the oxidizing agent between 21 vol .-% and 100 vol .-%. In particular, the temperature of the atmosphere within the melting tank or parameters of the melt itself, such as temperature or viscosity, come into consideration as parameters for regulating the oxygen concentration. In addition to the oxygen concentration, the angular position of one or more burners can also be the subject of a control.

In a particularly advantageous embodiment of the invention, one or more burners of the burner assembly are designed for flameless operation. In this case, fuel and / or oxidant for one or more burners are diluted to such an extent by the admixing of recirculated fuel gases from the atmosphere of the melting tank that the ratio of fuel to oxidant shifts outside of the ignition range. In flameless combustion, the exothermic oxidation of the fuel is due to the dilution no longer localized, but in the entire furnace chamber, which is covered by the flameless burner. The flameless operation allows a more even

Temperature distribution in the melting tank, reduces the wear of the

Furnace walls and leads to lower _NOx concentration in the combustion gases.

The object of the invention is also achieved by a method for melting a good, in which a device according to the invention is used.

A preferred use of a device according to the invention consists in melting non-metallic materials, in particular ceramic frit or basalt. In particular, through the use of flameless air / oxygen mixing burners required for the melting of ceramic frit temperatures between 1200 ° C and 1650 ° C can be easily maintained with little use of fuel and to produce a very low NO _x exhaust gas. With reference to the drawings, an embodiment of the invention will be explained in more detail. In schematic views show:

1 shows a device according to the invention in a sectional view,

Fig. 2a: the burner assembly of the device of FIG. 1 in a front view and

FIG. 2b shows the burner arrangement from FIG. 2a in a sectional view along the FIG

Line B-B in Fig. 2a.

The melting apparatus 1 shown in FIG. 1 comprises a melting tank 2 with a feed region 3 for feeding a material, a receiving region 4 for receiving the melt 5 and a discharge channel 6 for removing the molten material from the melting tank 2 for further processing.

Furthermore, in the region of the discharge channel 6 in a manner known per se and therefore not of further interest here, a burner lance 7 or more

Burner lances be arranged whose task is the melt 5 on the way to further processing process steps on a given

Keep temperature.

To melt the material comes in the apparatus of FIG. 1 a

Burner assembly 8 is used. The burner assembly 8 is in a the

Entry area 3 opposite end wall 9 of the melting tank 2 and comprises a total of three arranged in a burner block 1 1 burner 12, 13, 14th

As shown in FIGS. 2 a, 2 b, the burners 12, 13, 14 are received in recesses 16, 17, 18 of the burner block 1 1. The recesses are formed such that an angle relative to the horizontal angular position of the burner 12, 13, 14 is made possible within the burner block 1 1.

The angle of attack a, the burner 13, 14 are dimensioned so that from the burners 13, 14, a melting zone 20 is subjected to a maximum of heat, in which the discontinued Good is melted. The melting zone 20 is preferably in the half of the melting tank 20 facing the entry area; of the Angle of attack a of the two burners 13, 14 relative to the horizontal depends on the geometry of the melting tank and is for example between 5 ° and 10 °. In order to achieve optimum application of heat to the molten zone 20, the burners 13, 14 may, in addition, additionally be oriented pointing toward a vertical center plane of the melting tank 20.

In contrast, the angle of incidence of the burner 12 is dimensioned such that a heat retention zone 21 is subjected to a maximum of heat within the half of the melt facing the discharge channel 6. The outgoing heat from the burner 12 thus serves in particular to keep the melt 5 at a predetermined temperature prior to discharge via the discharge channel 6 in the liquid state. The angle of attack ß of the burner 12 relative to the horizontal is therefore steeper than the angle of attack a of the burner 13, 14 and is - again in

Dependence on the geometry of the melting tank - for example between 20 ° and 45 °. In the embodiment, moreover, the burner 12 is received in the recess 16 such that the angle of attack ß - as by the

Double arrow 22 indicated in Fig. 2b - within a certain angular range, for example between 20 ° and 30 ° relative to the horizontal, varies and thereby the requirements of the respective melting task can be adjusted.

The burners 12, 13, 14 are in each case mixing burners of the type described in WO 2008 092763 A1, in which both air and oxygen are supplied as oxidizing agent via separate feeds, wherein the

Oxygen content in the oxidant can be varied continuously between 21 vol .-% and 100 vol .-%. Natural gas is used as fuel in the exemplary embodiment, but other gaseous or liquid fuels may also be used. The power of the two burners 13, 14 is the same while

Burner 12 may have a different performance; For example, the maximum power of the burners 13, 14 is 750 kW each, while burner 12 has a maximum power of 600 kW. The burners 12, 13, 14 are for the

flameless operation designed. In flameless operation, part of the

Combustion gases inside the melting tank 2 recirculated, whereby a uniform temperature distribution in the interior of the melting tank 2 is achieved. The power of the burners 12, 13, 14 and the respective oxygen content in the oxidizing agent can be varied and regulated as a function of parameters determined in the melt 5 or in the atmosphere inside the melting tank 2. By way of example, FIG. 1 shows temperature sensors 23, 24 which measure the temperature of the furnace atmosphere; however, other parameters, such as

Temperature or viscosity of the melt 5 enter into the regulation of the burner power. By means of the temperature sensors 23 24, which are arranged in the region of the ceiling of the melting tank 2 or the side walls (seen from the burner assembly 8 forth), the temperature in the atmosphere of

Melting tank 2, for example in the region of the melting zone 20 and the

Warming zone 21 detected and transmitted to a control unit, not shown here. The controller then controls the proportionate supply of air and oxygen and / or fuel to the burners 12, 13, 14 after one

given program depending on the values of the measured

Parameter. For example, the firing is set by the burners 12, 13, 14 so that in the case of soft ceramic frit, a temperature in the region of the holding zone 21 of 1360 ° C is maintained, in the case of hard ceramic frit a temperature of 1450 ° C.

During operation of the device 1, the material to be melted, for example ceramic frit, passes through the melting tank 2 in accordance with the arrows shown in FIG. The material is introduced via the entry region 3 into the melting tank and melted in the melting zone 20 by means of the burners 14, 15. The molten material passes into the holding zone 21, where it is kept by means of the burner 12 to a predetermined temperature. Subsequently, the molten material leaves the melting tank 2 through the discharge channel 6 and is then further processed (not shown here). Through the use of

flameless mixing burners as burner 12, 13, 14 is a very uniform, homogeneous heating of the melt 5 and the wear of the furnace walls of the melting tank 2 is reduced. As a result, the device according to the invention is particularly suitable for high-temperature applications. At the same time, nitrogen oxide emissions are significantly reduced over prior art melters. By using a burner assembly according to the invention, a significant increase in production compared to systems of the prior art can be achieved. So could by installing a

Burner assembly the production of certain ceramic frits in one

Furnace plant can be increased from approx. 20 t / d to 45 t / d.

LIST OF REFERENCES

1 device

2 melting tank

3 entry area

4 recording area

5 melt

6 discharge channel

7 burner lance

8 burner arrangement

9 front wall

10 -

1 1 burner stone

12 burners

13 burners

14 burners

15 -

16 recess

17 recess

18 recess

19 -

20 melting zone

21 warming zone

22 double-headed arrow

23 temperature sensor

24 Temperature sensor α, β angle of attack

Claims

claims

1 . Melting device with a melting tank (2), which has an entry region (3) for the material to be melted, a discharge channel (6) for molten material and a burner arrangement (8) arranged in a wall (9) opposite the entry region (3) and having a plurality of a burner (10) arranged burners (12, 13, 14), wherein at least two burners (12; 13, 14) of the burner assembly (8) are set at different angles such that on the surface of the melted Guts at least two zones ( 20, 21) with different heat effect.

2. Device according to one of the preceding claims, characterized

characterized in that the angular position of at least one burner (12, 13, 14) is adjustable.

3. Device according to one of the preceding claims, characterized

in that the power of at least one burner (12, 13, 14) can be regulated as a function of parameters measured in the melting tank.

4. Device according to one of the preceding claims, characterized

in that at least one burner (12, 13, 14) of the

Burner assembly (8) is operable with oxygen as an oxidant burner.

5. Device according to one of the preceding claims, characterized

in that at least one burner (12, 13, 14) of the

Burner assembly (8) is an air / oxygen mixing burner.

6. Apparatus according to claim 4, characterized in that the

Oxygen content of the air / oxygen mixing burner (12, 13, 14) supplied oxidizing agent in dependence on in the melting tank (2) measured parameters can be controlled. Device according to one of the preceding claims, characterized

in that at least one burner (12, 13, 14) of the

Burner assembly (8) is designed for flameless operation.

A method of melting a product using a device (1) according to any one of the preceding claims.

Use of a device (1) according to claim 1 to 6 for melting non-metallic materials, in particular ceramic frit.