WO2013068003A1 - Process and device for improving the performance of the regenerators in glass melting and refining processes in cross-fired furnaces with regenerative heaters - Google Patents

Abstract

The object of the invention is to provide a process and a device for improving the performance of the regenerators in glass melting and refining processes in cross-fired furnaces with regenerative heaters, wherein the previously described disadvantageous influences of the asymmetrical operating mode are to the greatest extent overcome and in this way not only is the quality of production increased but also the energy demand can be reduced considerably without adversely affecting the serviceability of the installation as a whole. According to the invention, depending on the firing direction, the removal of exhaust gases in the process is set at at least one port (12a, 12b) or chamber (12a, 12b) in at least one regenerator foot (1a) by means of at least one drive-controlled gate (2), wherein the control of the at least one drive-controlled gate (2) is performed by a control device (3). The device used for implementing the process provides at least one drive-controlled gate (2) at at least one port (12a, 12b) or chamber (12a, 12b) in at least one regenerator foot (1a), wherein the at least one drive-controlled gate (2) is connected to a control device (3). The application area of the invention is that of producing flat glass.

Description

Method and device for improving the performance of the regenerators in glass melting and leuterpr essessen in cross flame pans with

regenerative heaters

Method and device for improving the

Efficiency of regenerators in glass melting and people processes in cross flame pans with

Regenerative heating, especially for the

Flat glass position.

To produce flat glass, natural gas-fired melting furnaces are used, which operate after the transverse flammenpr inzip. This type of heat transfer is necessary for large tubs, but extremely inefficient. Massively dimensioned regenerators, which reduce the exhaust gas temperature of between 1,200 and 1,300 degrees Celsius on the regenerator head to an average of 520 to 550 degrees Celsius on the regenerator foot, are nowadays used to lower the energy requirement. The amount of heat released at the grid of the regenerators in a cycle time of 20 minutes is about 30 to 35 gigajoules. This energy is used to increase the temperature of the combustion air. This technology reduces the amount of natural gas required by about 33 percent. Nevertheless, for the production of the amount of glass, for example, 700

 Daily tonnes, depending on the design and age of the melting tank, are still 45 to 55 megawatts

Heat output needed. Only about one fifth of the supplied heat output is transmitted via the molten glass to the subsequent processes, such as the holding trough or working trough. The rest splits up and is released by the tank ventilation system or forwarded via the exhaust gas flow to the waste gas purification and / or CHP plant. The idea to increase the efficiency of the regenerators by any massive dimensioning by the energy content of the exhaust stream behind the regenerators can be virtually arbitrarily reduced, does not lead to the desired result.

Rather, the boundary conditions, such as a symmetrical extraction, an adiabatic system, an ideal flow through the regenerators and the connected trains, an ideal thermal conductivity in the regenerators and the elimination of impurities are taken into account.

The fulfillment of the boundary conditions is considered ideal

Regenerators and will not in practice

complied with, since the regenerators are not ideal

behavior.

Taking into account the maintenance of a temperature of 520 degrees Celsius at the transfer point for exhaust gas purification, two states are likely in which some of the boundary conditions are not met.

One condition is that the temperature is significantly lower than 520 degrees Celsius. It should be assumed that one of the ports of the regenerator arrangement does not exhaust the complete amount of exhaust gas, which was supplied at the opposite port as combustion air and gas, which is a

corresponds to asymmetrical operation. Furthermore, the outer skin is poorly insulated, so that much heat is emitted to the surface of the regenerator and through

Leaks False air enters the area of the regenerator or / and in the branch channels. This mixes with the exhaust gas flow and reduces the exhaust gas temperature at the outlet considerably. In addition, moisture is removed from the exhaust stream by evaporation of moisture. Another condition occurs when the temperature

significantly higher than 520 degrees Celsius. The reason for this is that the considered port of

Regenerators arrangement sucks more exhaust gas than is caused by the opposite port by the combustion, and the thermal conductivity of the lattice blocks of the regenerators is too low, so that the heat transport within the lattice is not ideal. In addition, it is conceivable that the grids are dusty or even glazed, whereby they no longer allow ideal heat transfer.

The extraction is considered to be symmetrical if, on the one hand, the combustion gases, caused by the burners at one port, are completely absorbed by the opposite port, ie sucked out and, on the other hand, the

Loss of ignition losses resulting from the melting of the mixture, be absorbed by all ports in equal parts. In practice, these two conditions do not apply. Due to different pressure losses in the

individual ports, caused by different

Dusting or glazing effects as well as unfavorable exhaust gas routing, the exhaust gas quantities become asymmetrical

aspirated. In the most extreme case, the exhaust gases are routed past the opposite ports. Because the

 Combustion air temperature is limited to about 50 to 100 Kelvin lower than the exhaust gas temperature, the additional amount of heat in the congested ports can not be removed. The result is a significant increase in the average operating temperature in these ports. At the same time, the average operating temperature of the regenerators drops extremely in the virtually unloaded ports. The consequence is a strongly falling one

Outlet temperature of the combustion air at these ports. Such cases show in a comprehensible manner the potential which can be achieved by ensuring the symmetric Driving style exists. Due to the extremely asymmetrical driving style, the efficiency of the regenerators is easily 20 percent lower than in the ideal case. At a 700

Daily tonnes tub corresponds to a power reduction of 5 megawatts or an additional amount of natural gas of approx. 500 m ³ N / h. At current energy prices, this means additional costs of 1.3 million euros per year.

So it is disadvantageous that by handling the

Outgoing exhaust from the ports the asymmetric

 Operating mode not or too little in favor of a symmetrical operation of the regenerators

being affected. Currently, the amount of exhaust gas passing through the ports and regenerators is adjusted by means of manually operated hand slides and remains in that position during the process and is rarely readjusted. A permanent and dynamic adaptation does not take place. The necessary for a high production quality

 Pressure stability in the melting tank and in the main exhaust gas channel, represents the previously unavoidable asymmetric

Operation is a big problem. DD 143 242 AI describes a method for

 Stabilization of the hearth space pressure, preferably for regenerative and cross-heated glass melting tanks, in which the pressure in the glass melting tank at one or more points measured and the measured values are each a controller switched on the deviation from the setpoint actuates an actuator in the associated exhaust duct and continue to the Exhaust gas quantity in other exhaust ducts is regulated by one or more exhaust gas quantity control loops. This should be favorable flow and pressure conditions in the furnace atmosphere in large glass melting tanks

be created. The task of pressure fluctuations in the Is reduced by the existing measuring points remote areas is solved by a from the negative pressure in the exhaust system or chimney foot, the fuel and

Combustion air quantity of the individual burners, the

Intake temperature of the combustion air and the

 Exhaust gas temperature weighted by a correction element

Mean value as a reference variable the hearth pressure regulator and / or the exhaust gas regulators are switched. In DE 42 36 677 AI a method and a

 Described apparatus for combustion air distribution to regenerative cross flammenwannenöfen. At regenerativbeheizten cross flammenwannenöfen there is often the need to go beyond the largely structurally defined for the individual flammable combustion air distribution, or

regardless of a section-wise exhaust throttling, to carry out a needs-based combustion air distribution in order

to achieve improved performance and energy economic parameters. According to the invention, gas pressure lances and / or through-burner are arranged in regenerators or burner ducts in such a way that by means of their gas pressure jet, in the

Countercurrent the gas-dynamic blocking throttling and / or in direct current according to the jet pump principle, the amplification of partial flows of the combustion air by means of

Actuators in the feeding pressure line system

be set.

Furthermore, in DE 31 07 270 AI a method and apparatus for supplying combustion air to the opposite ends of the regenerators of

 Regenerative glass melting furnace, in which for supplying and regulating the flow of combustion air to the opposite ends of regenerators of a regenerative glass melting furnace after the tray system, to reduce a localized overheating and a

more uniform heat distribution of brick constructions To achieve regenerators and thus increase the efficiency of the furnace and to extend the life of the regenerators. To achieve this, a larger proportion of the combustion air is the regenerators on their

fed downstream ends while a

less of the combustion air is supplied to the upstream ends by conduits having valves for reversing and damping and for adjusting the proportion of the combustion air flowing to the opposite ends of the regenerators.

The object of the invention is to provide a method and a

Device for improving the efficiency of regenerators in glass melting and liquefaction processes in

To create transverse flame pans with regenerative heaters, the above-described adverse effects of asymmetric operation are largely eliminated and in this way in addition to the increase in

Production quality and energy consumption can be significantly reduced, without affecting the functionality of the entire system.

With the invention is achieved in the specified application, that a method and an apparatus for

To improve the performance of the regenerators in glass melting and Leuterprozessen be created in transverse flames with regenerative heaters, depending on

Direction of firing the amount of exhaust gas discharged through the ports in the regenerator feet is adjusted by means of drive-controlled slide and the regulation of

drive-controlled slide via a control device takes place. In this case, there is the advantageous possibility to adjust the amount of exhaust gas dynamically so that the

Regenerators depending on a static exhaust gas removal or combustion air supply to achieve their maximum performance. In addition, it is possible that in the main exhaust duct to stabilize existing pressure conditions. In addition to the individual streams of exhaust gases conducted through the ports or chambers, it is necessary to control the entire mass flow

reliably dissipate. This can be done by the

lossy regenerators from the sum of

deviate initiated individual streams of combustion air. By the regulation of the slide becomes in addition a

Equal treatment of regenerators per port favors. This reduces unfavorable asymmetries and enables symmetrical operation. In addition, the energy demand is greatly reduced, since the exhaust gas is discharged to the extent, as well as for the heat exchange through the ports or chambers in the regenerators after the

Combustion is needed. Occurring weaknesses in the regenerators due to contamination or glazing as well as heat losses can be largely compensated.

Advantageous embodiments of the method are shown in claims 2 and 3 and the device in claims 4 to 7. The method undergoes a development according to claim 2, the pressure in the main exhaust duct is measured. Occurring pressure fluctuations are by adjusting the opening degree of the drive-controlled slide

balanced. The current structural conditions mean that the pressure prevailing in the main exhaust duct pressure with the juxtaposed ports or

Chambers varied during the course of the arrangement. This means that at the closer to the downstream exhaust gas purification ports or chambers, the pressure conditions

are cheaper than at the downstream

Exhaust gas cleaning remote ports or chambers. This balancing and adjusting the pressure is performed by the control device by means of the adjustment of the

Opening degree of the slide dynamic and very fast. The melting process takes place in a higher quality. The symmetrical operation is further favored. Unequal loading of the regenerators on the respective ports or chambers can thus be counteracted even better. According to claim 3, the temperature is

Regenerator foot measured and based on this will be the

 Slider changed in opening degree. Thus, significant overheating or hypothermia are avoided. Significant deviations of the target for the onward exhaust gases to the exhaust gas purification temperature are detected and based on the change in the opening degree of the slide

dynamically adjusted. It also applies here that the symmetrical mode of operation is further favored. The extreme case that a port or a chamber does not remove exhaust fumes can thus be recognized. By adapting the valves, poorly flown through ports or chambers can specifically be exposed to exhaust gases.

In the device after Nebenanspruch 4 is at

Transverse flames with regenerative heating in the

Regenerator foot drive controlled slide depending on

Lighting direction for adjusting the amount of exhaust gas present and connected to a control device. Due to the controlled access, the sliders are dynamic

adjustable, that negative influences of asymmetry

be compensated as far as possible and thus one

achieve symmetrical operation of the regenerators.

 According to claim 5, the device is further improved by pressure sensors are present in the main exhaust duct.

As a result, it is possible to react directly to pressure fluctuations by influencing the degree of opening of the slide by the control device. The desired symmetrical operation is further favored. According to claim 8, a temperature sensor is provided in the regenerator foot. Thus, the exhaust gas temperature is measurable. Large deviations from target temperatures about the 520 degrees

Celsius, counteracts, by virtue of the measurement of the temperature over the control device the Slider position is changed. Thus, the symmetrical operation is further favored.

An embodiment of the invention is shown in the figure 1 and will be described in more detail below. It shows a sectional view of a transverse flame tray with regenerative heaters with the invention

drive-controlled slides. FIG. 2 schematically shows the asymmetric operation and, in FIG. 3, the symmetrical operation.

In the inventive method for improving the performance of the regenerators 7 in Glasschmelz- and Leuterprozessen in transverse flammenwannen 8 with

Regenerative heaters are in regenerator feet 1 at the ports 12a, 12b or chambers 12a, 12b located slide as a drive-controlled slide 2 by means of a

Control device 3 is set in its opening degree. This control affects the amount of exhaust gases and takes place under consideration of the direction of firing and taking into account the pressure in the main exhaust duct 5 and the temperature in the regenerator foot 1 at the ports 12a, 12b or chambers 12a, 12b. The temperature is using

Temperature sensors 6 and the pressure in the main exhaust duct 5 by means of pressure sensors 4 and measured by the

 Control device 3 detected. Depending on the direction of firing, the connection from the ports 12a, 12b or chambers 12a, 12b to the main exhaust duct is opened or closed with the interchangeable valves 9. At the usual

used transverse flame pans 8 are at the two

opposite side of the transverse flame trough arranged regenerators 7 each have four or six ports 12a, 12b, through which, depending on the firing direction, the combustion air 10 is guided to the burners and the exhaust gases 11 is discharged at the opposite ports 12b again. There is the possibility that the Exhaust gases 11 are not or only partially conducted through the respective opposite ports 12b. There is an uneven load of the regenerators 7, which leads to overheating or hypothermia, since the sucked combustion air 10 only heats up to a maximum temperature and the available heat in the regenerators 7 does not completely and the exhaust gases 11 Continue to heat the regenerator. On the other hand, in the case of a poorly perfused regenerator 7, the cold combustion air 10 further cools the regenerator 7 in this area. As a cause, the pollution of the grid 13 of the regenerators 7 may be mentioned. Furthermore, loss-inducing influences such as false air or

To call moisture. This makes it possible that the flow of exhaust gases between two opposite ports 12 or chambers 12, the transverse flammenwanne 8 happens and on each adjacent ports 12a, 12b or

Chambers 12a, 12b distributed. This behavior is shown in FIG. These disturbing factors or effects

cause asymmetric operation of the

 Regenerators 7 and ensure a high energy demand. To avoid these asymmetries are with this

Method set the drive-controlled slide 1 so that the discharged mass flows of the exhaust gases 11 through the ports 12a, 12b or chambers 12a, 12b are equal to the known mass flows of the supplied combustion air 10, whereby the symmetry is established. Depending on

Lighting direction is with the setting of the

drive-controlled slide 2a, 2b, the exhaust gas flow of the respective ports 12a, 12b adjusted so that the

 Pressure conditions along the accesses of the ports 12a, 12b to the main exhaust duct 5 are largely constant. With the drive-controlled slides 2a, 2b can be the

Conduct mass flows of the exhaust gases 11 so that the regenerators are evenly loaded. Depending on the need for the drive-controlled slide 2 backpressures produces a low degree of opening or the exhaust gases 10 pass with fully open drive-controlled slides 2 this almost unhindered. The supply of

Combustion air takes place independently of the degree of opening of the drive-controlled slides 2a, 2b, since fans are in use for this, which can be adapted in their performance. Thus, the overheating or undercooling described above will be avoided. By the mentioned

Measures symmetrical operation per port pair, as shown in Figure 3, achieved. In addition to the increase in production quality, this also results in a cost savings.

In the inventive device for improving the performance of the regenerators 7 in Glasschmelz- and Leuterprozessen in transverse flammenwannen 8 with

 Regenerativheizungen are, as shown in Figure 1, in regenerator feet 1 at the respective ports 12a, 12b or a chambers 12a, 12b drive-controlled slide. 2

available with which the flow of exhaust gases 11 is regulated. These drive-controlled slide 2 are with a

Control device 3 connected. The drive-controlled slide 2 can be adjusted in their opening degree. This affects the amount of exhaust gases. to

Detection of the pressure in the main exhaust duct 5 are in

Main exhaust duct 5 pressure sensors 4 available. to

Temperature measurement in the regenerator foot 1 at the respective ports 12a, 12b or chambers 12a, 12b are

 Temperature sensors 6 arranged. These sensors 4, 6 are connected to the control device 3. The

Change shifter 9 are also with the

Control device 3 connected. The shifter 9 separate the regenerator foot 1 from the main exhaust duct 5, so depending on the direction of firing no combustion air 10 passes directly into this. With this method and the device, all the ports 12a, 12b or chambers 12a, 12b can be adjusted individually so that the symmetrical operation is possible independently of the direction of firing.

Compilation of the reference numerals

1 - regenerator foot

 2 - drive-controlled slide

3 - Control device

 4 - Pressure sensor

 5 - main exhaust duct

 6 - temperature sensor

 7 - regenerator

 8 - Melting tank, transverse flame pans 9 - Change spool

 10 - combustion air

 11 - exhaust

 12 - port, chamber

 13 - grid

Claims

claims 1. A method for improving the performance of the regenerators (7) in glass melting and Leuterprozessen in transverse flame pans (8) with regenerative heating, characterized , depending on the firing direction, the exhaust gas removal at at least one port (12a, 12b) or a chamber (12a, 12b) in at least one regenerator foot (1) by means of at least one drive-controlled slide (2) is set and the control of the at least one drive-controlled slide (2) with a Control device (3) takes place. 2. The method according to claim 1, characterized , in that the degree of opening of the drive-controlled slide (2) is adjusted according to the measurements of at least one pressure sensor (4) in the main exhaust duct (5). 3. Process according to claims 1 and 2, characterized , that the opening degree of the drive-controlled slide (2) after the measurements of at least one temperature sensor s (6) in the regenerator foot (1) is adjusted. 4. device for improving the performance of the regenerators (7) in glass melting and Leuterprozessen in transverse flame pans (8) with regenerative heating, characterized , that at least one port (12a, 12b) or a chamber (12a, 12b) in at least one regenerator foot (1) at least one drive-controlled slide (2) is present, wherein the at least one drive-controlled slide (2) is connected to a control device (3). 5. Device according to claim 4, characterized , in that at least one pressure sensor (4) is present in the main exhaust gas duct (5), the pressure sensor (4) being provided with the Control device (3) is connected. 6. Device according to claims 5 and 6, characterized , that in the regenerator foot (1) at least one temperature sensor (6) is present, wherein the at least one Temperature sensor (6) with the control device (3) is connected.