SU791659A1 - Bath glass-smelting furnace - Google Patents

Description

one

The invention relates to bath glass furnaces of continuous action and can be used in the manufacture of sheet glass. ,

Recently, in the production of flat glass, furnaces are becoming more and more common, in which, along with the supply of heat into the furnace’s fiery space (by burning | g of gas or liquid fuel), heat is introduced directly into the glass mass by passing electric current through it.

Practice has shown that heat input due to electricity is ho. 15 tools to increase furnace productivity, reduce specific heat consumption, extend the working campaign of glass melting plants and improve the quality of glass melt., 20

In addition, due to the possibility of selectively introducing heat into localized areas of a glass melting furnace, it is possible to be operative. process control .25

Glass-melting furnaces are known in which, along with the means for controlling the transverse convection of glass melt in the charge zone, the electric heating system plays the role of a temperature controller30

in the charge loading zone to prevent the loading pocket from freezing while increasing the productivity of the furnace 1.

The disadvantage of such measures is to recognize a small amount of electricity supplied to the furnace, since the electrodes can be located only in the boot pocket, where the temperature of the glass mass and, consequently, its electrical conductivity is extremely low. In addition, the possibility of controlling the transverse convection of the glass mass from the boot pocket, the latter depends only on the temperature of the glass mass in the furnace itself, which, in the absence of electric heating from the pool, is determined primarily by the conditions of fuel combustion.

A glass furnace is also known in which, at the end of the cooking zone, a transverse row of vertical electrodes is installed, which serves both to introduce additional heat and to increase the temperature barrier, and the role of controlling transverse convection is assigned to the longitudinal row of Sbarboter electrodes located to work out.

This furnace is characterized by the fact that it lacks control over the cross convection only in the melt refining zone, and not in the charge cooking zone, which is a more urgent task for furnaces, especially large capacity. In addition, as the practice of bath furnaces has shown, installing electrodes just outside the cooking zone does not provide a significant performance increase due to a decrease in temperature in the boot pocket and the area adjacent to it below the permissible level.

The closest to the invention in technical essence and the achieved result is a furnace, including an elongated basin with a cooking zone located in it, to which a loading pocket adjoins on the front side, a clarification zone in which the glass melt does not contain unwelded particles of the charge, a zone homogenization of the melt and the working part.

The furnace is also equipped with a primary system (plasma heating is equipped with an electric heating system consisting of spacers in the cooking zone and longitudinal clarification of transverse rows of vertical electrodes that separate all the boiling points and lightning in a row of control columns one after another in the longitudinal direction glass melts 3. These transverse rows of electrodes are connected both to the main power circuit and to the additional power circuit having a regulating device for changing the current through which the electrodes are passed through the electrode regardless of the main supply circuit. The basic idea behind this furnace design is that by regulating the voltage applied to the transverse rows of electrodes that limit the control column of the glass melt, it is possible to regulate the upward flow in the column with respect to the downward flows along the borders of the column. Due to this, it is possible to completely control the longitudinal convection of glass of the mass both in the cooking zone and in the clarification zone.

However, along with the wide possibilities of controlling the longitudinal convection in this furnace, it is not possible to influence the transverse convective flows of the glass melt. Taking into account that even with a uniform distribution of the input heat in the cross section of the furnace, the temperature at the pool walls will be lower than at the center of the furnace (as a result of heat loss to the environment), the furnace will melt convective glass mass flows from the basin axis to the periphery. This effect will lead to a decrease in the possible performance of the furnace, a decrease in the working campaign of the glass melting plant and a deterioration in the quality of the glass melt.

The invention is based on the task of creating such a design of a glass melting furnace in which the input of heat due to electric power would allow, together with an increase in the productivity of the furnace, to regulate both longitudinal and transverse convective flows of glass melt.

The purpose of the invention is to increase the productivity of the glass furnace, extend its working campaign and improve the quality of the glass melt.

This goal is achieved by the fact that in a glass furnace furnace containing a cooking zone with a boot pocket adjacent to it from the front side, a zone of clarification, homogenization and generation of glass melt, burners and electrodes installed in the zones of cooking and clarification, electrodes installed in the zone of cooking , are arranged in an arc symmetrical with respect to the longitudinal axis of the furnace and facing towards the working area of the furnace, with a radius of 0.4–2.0 of the furnace width, while the electrodes nearest to the loading pocket are separated from the face oh furnace wall at a distance of 0.03-0.15 furnace width.

The essence of the invention is as follows.

The temperature field of the glass melt in the bath furnace is substantially non-uniform. In the longitudinal section of the furnace, the glass melt temperature rises from the loading pocket to the so-called quelpoint of the furnace, and in cross section from the side walls to the longitudinal axis. As a result, transverse and longitudinal convection occurs in the glass melt, in the upper part of the basin, directed from the quill point to the loading pocket and from the longitudinal axis and side walls of the furnace. The resultant flows of these flows can be schematically represented as radii-rays emanating from the zone of maximal temperatures of the glass melt towards the loading pocket. When electrodes (or centers of groups of electrodes) are deployed along the arcs corresponding to these radii, the operator technologist, by selectively adjusting the power supplied to a separate group of electrodes, makes it possible to influence both transverse and longitudinal convection of the glass melt.

Since the location of the zone of maximum temperatures of the glass mass depends on many design and operational parameters (ratio of length and width of the furnace, the specific capacity of the installation, the distribution of gas along the length of the furnace and its condition, etc. (/; then the length of the radii of the arcs and their position centers may vary widely.

FIG. 1 shows an exemplary diagram of the resulting flows in the upper layers of the glass melt and the charge cartogram in the cooking zone; in fig. 2 and 3 - the location of the electrodes in the bath furnace, options.

The glass-melting bath furnace, fenced with end 1 and side walls 2, hearth and vault G (not shown in the figures), contains a boot, pocket 3, charge cooking zone 4, zone 5 for clarification and homogenization of the melt as well as the working one. Part 6. The furnace is equipped with a primary heating and melt heating system, consisting of several pairs of burners 7, built into the side walls 2 of the furnace through which the main part of the heat required for technological conversion is introduced by burning gas fuel.

In zone 8 of the maximum glass melt temperature, in three transverse rows, eighteen vertical MO-Libden electrodes 9 inserted through the furnace bottom, connected to power sources, are installed. In this case, the distance to the melody by adjacent rows of electrodes and electrodes in one row is approximately equal to the depth of the basin.

In the cooking zone of the charge in an arc of a circle with a radius equal to approximately the width of the furnace, with the center located on the longitudinal axis of the furnace, four three-electrode groups of 10 and 1 vertical, inserted through the bottom of the electrode furnace, are installed. In this case, two central groups of 10 electrodes are located in the immediate vicinity of the loading pocket; (at a distance equal to 0.03–0.15 width of the furnace from the end wall)) and serve to control the temperature of the glass melt in the loading zone of the charge, and the other two 11 are close to the side walls of the furnace (the distance of the centers of these groups from the side walls does not exceed 0.13 of the furnace width)) and serves mainly to control the transverse convection of the glass melt.

Both central 10 and lateral 11 groups of electrodes are connected to independent power sources. Bottom thermocouples 12 are installed in the zones of location of the electrode groups.

The glass furnace works as follows.

The thoroughly mixed components of the charge, along with the glass breakage, are fed into the loading pocket 3 to melt glass mass. Under the mechanical action of the loader, the charge enters the cooking zone 4, where the process of its heating, melting and dissolving the refractory components takes place. In the absence of an additional electrical heating system to ensure normal

process flow at a productivity of 360 tons / day.,. 3700-3800 m / h of gas with a caloric content of 8300 kcal / m must be supplied to the furnace.

To ensure the kiln's performance is 430 tons / day. An auxiliary electrical heating system is put into operation, located in the heater point of a 2500–2800 kVA furnace. With a further increase in productivity, the glass melt temperature in

0, the boot pocket according to the indications of the bottom thermocouple 12 drops below the required level at which the glass mass of the required quality is produced. To provide the required

Level 5 of the temperature in the charge loading zone turns on the central groups of 10 electrodes, and the required power is regulated either by switching the transformer steps or by special

0 by a regulating device connected by a temperature sensor, or in any other way {for example, due to different emission of electrodes). Since the temperature of the glass melt near the furnace walls will decrease, there is a danger of increasing transverse convection, which will lead to the movement of the charge into the near-wall region with all the negative consequences that follow from this. To prevent

At the same time, along with the central groups of electrodes, side groups 11 are included. In this case, calculations show that the ratio of the power introduced into the side groups 11 to the power of the central groups 10 should be in the range of 1.2-1.5, and the total power of the groups electrodes 10,11 located in the cooking zone is 50-80% of the power of electric heating

0 in the furnace kiln.

When a power equal to 1,300 kVA is introduced into the cooking zone, the increase in productivity will be in the order of 35 tons / day. Estimated economic efficiency at the polished kiln

5 glasses only due to increase in productivity will make more than 300 thousand rubles. in year. Overall economic efficiency from the implementation of the proposed design of glass bath

The furnaces will be expressed in lowering the specific capital expenditures, the specific fuel consumption, increasing labor productivity, extending the operating campaign of the furnace and improving the quality of the products produced.

Claims (3)

1. US Patent No. 3926606, cl. 65-135, published. 1975, 2.Patent UK 1039952 cl. With 1 M published in 1966. 3.Patent UK No. 1428354 cl. F 4 V, pub. 1976 / (prototype)).