JPS58199728A - Glass melting furnace - Google Patents

Abstract

PURPOSE:To eliminate hindrance to the continuous operation of a glass melting furnace and to further refine glass by installing a submerged combustion burner to remove bubbles formed in molten glass. CONSTITUTION:This glass melting furnace is composed of a melting vessel 1, a bubble removing vessel 2, a refining vessel 3 and a glass discharge section 4 arranged in the order. The partition wall 24 between the vessels 1, 2 is provided with a passage 25 for molten glass in the vicinity of the surface of the molten glass, and the partition wall 22 between the vessels 2, 3 is provided with a passage 23 for molten glass close to the bottoms of the vessels. A submerged combustion burner 17 is installed in the vessel 1. When town gas and air are fed to the burner 17 and burned, bubbles formed in molten glass in the vessel 1 are fine, the surface of the molten glass rises slightly, and bubbles are scarcely observed in the vessel 3.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a glass melting furnace, and more particularly to a glass melting furnace, which defoames bubbles in molten glass generated by the use of a submerged combustion burner, eliminates trouble during continuous operation, and melts glass. This invention relates to a glass melting furnace that allows for better clarity.

BACKGROUND ART Conventionally, wires, mainly glass melting tank furnaces, have been used to melt glass raw materials to produce glass.

As shown in Fig. 1, this glass melting furnace usually consists of a round melting tank 1 that melts glass raw materials to make glass, and a refining tank 11b (also called a working tank) that refines the molten glass. The melting tank and the fining tank are connected by a type of communication pipe d called a throat near the bottom of the tank. has been done. Usually, the lower part of each oval holds molten glass, and the upper part is a combustion chamber for fuel for heating the glass.

In such a glass melting tank furnace, the temperature of the melting tank a varies somewhat depending on the type of glass, but generally it is between 1500 and
A temperature of 1600'C is required, and this temperature is
Fuel is obtained by burning fuel, mainly heavy oil, in a combustion chamber e provided at the top of the engine. In other words, the glass must be melted by indirect heating, so the thermal efficiency of the furnace is extremely high.
There was a low drawback.

Therefore, in order to improve thermal efficiency, a submerged combustion method has been proposed in which the glass filler is heated directly and melted.

The submerged combustion method heats the glass melt by injecting the flame obtained by the burner and the high-temperature combustion gas directly into the glass melt.When a submerged combustion burner is used to heat the glass melting tank. There is an improvement in thermal efficiency and an improvement in the stirring effect due to the floating of the combustion gas inside the molten glass.

However, since molten glass has viscosity, when the high-temperature combustion gas reaches the molten glass liquid, it bursts into large bubbles, generating many small bubbles at the time of bursting. In addition, if the glass raw materials that have been introduced do not necessarily fully decompose and become oxides before entering the molten glass, cracked gas will be generated from the raw materials that are not fully decomposed, and bubbles will form in the glass. form. Does it take? The amount and size of 11II vary considerably depending on the viscosity of the glass, the amount of combustion gas directly blown into the molten glass, the number of bursts of large bubbles on the surface of the molten glass caused by the combustion gas, and other factors.

Some of the bubbles generated in this way disappear over time, but the balance between the generation and disappearance of bubbles is disrupted, and air,
If the bubble generation rate increases, the glass liquid level in the molten metal will bubble and gradually rise to the top, making continuous operation impossible. In addition, for practical glass, it is necessary to remove bubbles to a certain level, but bubbles caused by submerged combustion burners are
As mentioned above, the bubbles generated by normal glass melting differ in the thickness of the bubble formation layer, so the normal inertia method does not completely remove the bubbles, so the bubble removal method is suitable for the submerged combustion method. One shot was expected.

Therefore, the present invention can be considered in consideration of such lumps (4), and improves the heating efficiency of a glass melting furnace by conveniently using a submerged combustion burner, as well as by using a submerged combustion burner. It has the following features: it can sufficiently degas 1i1 to obtain clear glass, prevent the glass liquid level from rising due to the generation of bubbles in the melting tank, and enable continuous operation. It is something to do.

That is, in the glass melting furnace of the present invention, a melting tank, a defoaming tank, a clarification tank, and a glass flow/upper part are arranged in this order, and the gap between the melting tank and the defoaming tank is A flow path for the molten glass is formed near the liquid surface of the molten glass, and a flow path for the molten glass is provided near the bottom of the tank in the partition between the defoaming hinoki and the clarification tank. It is characterized by a submerged combustion burner attached to the cypress wood.

The following is an example of the present invention shown in the drawings. I'll clear the rice cake.

FIG. 2 is a cross-sectional view showing the structure of the glass melting furnace of the present invention, and FIG. 3 is a cross-sectional view showing the installed state of the submerged melting burner used in the present invention.

As shown in FIG. 2, the glass melting furnace G of the present invention includes a melting tank 1 surrounded by a refractory material, and defoaming tanks 2 and 2 disposed adjacent to the melting tank 1, respectively. It consists of a clearing tank 6 and a glass outflow section 4.

A partition 2 made of fireproof material is provided between the melting tank 1 and the degassing tank 2.
A throat 25 of a molten glass flow path connecting the melting tank 1 and the defoaming tank 2 is formed in the partition 24 near the molten glass liquid surface. Here, near the glass liquid level means a state in which the throat 25 is partially submerged in the glass liquid, or a state in which the throat 25 is completely submerged in the glass liquid near the glass liquid level.

On the other hand, a partition 22 made of fireproof material is also provided between the defoaming tank 2 and the clarifying tank 6, and a throat 23 connecting the defoaming tank 2 and the clarifying tank 6 is formed near the bottom of this partition 22. It is. Furthermore, a human-resistant partition 26 is similarly formed between the clarification tank 6 and the glass outflow section 4, and a throat 27 is provided at the bottom of the partition 26, and a glass outflow port 18 is provided at the bottom of the glass outflow section 4. It is formed.

Further, in the upper space of the six tanks 1.2, 5.4, indirect heating devices 5, 6, 7.8. Thermocouples 9, 10, 11, 12° and air outlets 28, 29, 30, 51 are provided, respectively, and the thermocouples 15 located in the molten glass are
, 14, 15 and 16 are provided, respectively.

On the other hand, the melting tank 1 is equipped with a submerged combustion burner 17, and the melting tank 1 is equipped with a submerged combustion burner 17. A pair of heating electrodes 21 and 20 are provided in the molten glass of f41 and the defoaming tank 2, respectively, and a glass raw material inlet 19 is formed in the melting tank 1.

Indirect heating II customary 5,6.7.8 + □1iJl, for example, by burning the supplied city gas, preheat the 6 tanks, tf
The heating electrodes 21 and 20 are also used for the purpose of maintaining the temperature of the molten glass, and although it is not necessary to provide these indirect heating devices and the 11 poles, they promote the bubble breaking effect of the defoaming tank, It is preferable to install one in order to expand the range of conditions for continuous operation.

The submerged combustion burner 17 used in the melting tank 1 can be of the conventionally used type, as appropriate. For example, as shown in FIG.
2K, the combustion gas outlet brick gutter 6 is installed at an angle of 45' to AltOs -zrot -s to
W-based electroformed products are used.

The fuel used in the burner 17 is not particularly limited either, and for example, city gas of 4,500 ''/p4- can be used after being pressurized by a compressor to about 1''/cit.

The glass melting furnace of the present invention is operated, for example, as follows. First, indirect heating burner 5.6, 7.8
4566 &cs in order to preheat the inside of the furnace by
l/,, @ city gas each for 29.5 ''>hr.

10.3”/hr lts, ONrrL/hr
+ and 6J N”/hr and burned with an air ratio of 1:1. 1+, SIO at pre-weight -, 70%
, NatO17.7%, CaO9.45, A
tOm2.4%, and A1. A commercially available granular raw material having a composition of O, α511 was melted in a separate furnace and charged as current into six tanks to a predetermined height. thermocouple 9,
10, 11 and 12, good melting side 1, defoaming tank 2
, the atmospheric temperature in the upper space of the clarification tank 6 and the glass outflow section 4 is 1,425°C, respectively.

The temperatures were 1.350°C, 1,420°C, and 1,345°C.

Also, thermocouple 1M, 14. The nine glass temperatures measured at 15 and 1,265℃, 1,200℃, and 1, respectively.
The temperature was 350°C. Furthermore, without changing the amount of city gas supplied to the indirect heating burner 6, l0 is supplied to the heating electrode 20 of the defoaming tank 2.
When the KW power is supplied, the atmospheric temperature of the defoaming tank 2 is 1.
, 420°C, and the glass temperature a rose to 1,300°C.

Next, in this state, the melting tank 1 is equipped with the combustion burner 1 in the mourning liquid.
7 to 9”/hr of city gas and air, with an air ratio of 1
They were burned at a ratio of 1 to 1 and combustion gas was blown into them. Melting vI when asking questions! J1 indirect heating burner 50 city gas amount 29.
5 N'/hr to 20.5 N''>hr K was decreased.As combustion gas was blown from the submerged burner 17, bubbles were observed in the molten glass in the melting tank 1,
The bubbles were small and no molten bubbles could be observed.Although raw glass was continuously introduced from the raw glass inlet 19 at a rate of xoKI/hr, stable continuous operation was not possible, and no bubbles were observed in the clarification tank 6. was hardly seen.

Note that when the continuous feed rate of raw glass was increased to 30'f/hr, the glass liquid level in melting tank 1 rose considerably, and a
The input amount of oK9/hr was determined to be the limit amount that allows continuous operation. However, even in this case, almost no #1 bubbles were left in the glass obtained from the glass outlet 18. However, when the power supply to the electrode 20 of the defoaming tank was stopped, 10 Kf
The glass temperature decreased to 1,190° C. with raw material input of /hr, and the presence of bubbles was observed in the glass obtained in the refining tank δ. Also, in the state of raw material input of 30Kg/hr, the temperature drops to 1.172)℃, and in the state where the glass temperature is rising, the amount of town gas used by indirect heating burner 6 is increased to 15N'/hr. It burns at an air-to-air ratio of 1:1.

This K caused the atmospheric temperature to rise to 1,500°C, but the glass temperature was only 10°C regardless of the amount of raw material input.
The glass bubble shape obtained in clarifier 6 remains unchanged by increasing the temperature by only 20°C.

The defoaming effect of molten glass according to the present invention is considered to be due to the following reasons.

In other words, the bubbles generated on the molten glass liquid surface in the melting tank 1 are
It moves to the defoaming 11F2 via the throat 25 and collects only on the glass liquid surface of the defoaming tank 2 due to its specific gravity. In addition, there is a large convection in the melting tank 1 due to the injection of combustion gas from the submerged combustion burner 17, but the glass containing a large amount of bubbles in the melting tank 1 has a throat 25 near the glass liquid surface. Since it is provided, it does not directly migrate to the middle or lower part of the defoaming tank 2, and the defoaming and clarification actions in the defoaming tank 2 are not obstructed.

However, as the continuous operation progresses, the surface of the glass liquid in the degassing tank 2 becomes covered with a glass layer containing a large amount of bubbles, and the heat insulating effect of the bubbles prevents the indirect heating burner 6 from increasing the glass temperature. This tends to reduce the defoaming effect in the defoaming tank 2. Therefore, if the defoaming tank 2 is provided with an electrode 20 for direct heating in addition to the indirect heating device 16, the glass temperature of the defoaming tank 2 can be raised extremely efficiently, the removal of bubbles is promoted, and the bubbles are removed. After cutting, only the 9 glasses move to the lower part of the tank and are sent to the clarification tank 6 from 4-25.

K had the following effects.

! 10! Comparing KK with input at the rate of whr,
The temperature decreases by about 40°C, which makes it difficult to break out the bubbles9.The number of bubbles in the glass in the melting tank 1 increases, and the glass liquid level gradually rises, making it difficult to continuously feed glass raw materials. 2
For example, when approximately 10 KW of power is supplied to the melting tank 1, even though there is a large convection in the melting tank 1 due to the floating of combustion gas by the submerged combustion burner 17 and the floating of bubbles 26, the power is stably supplied. can be supplied, the glass temperature in the molten yuzu 1 rises by about 50℃, and the glass liquid level increases by 10KVhr.
The temperature returned to 11tC when the raw materials were added. The condition of the glass bubbles collected in the clarifying tank 6 was the same as when the raw material was continuously fed for 10 hours without using the electrode 21. Also,
The amount of city gas supplied to the submerged combustion burner 17 is increased from 9 N''/hr to 11 NWL/hr K without using the electric power & 21, and the amount of heat transferred to the electrode 21 is increased. The glass temperature rise was only 10°C.Furthermore, instead of using the electric 1121, a submerged combustion burner 1 was used.
At a city gas supply rate of 9 N''/hr to indirect heating burner 5, the city gas supply rate to indirect heating burner 5 was increased from 2αB''/hr to 22.5 N'/hr K, but no increase in glass temperature was observed. There wasn't. From these facts, it is thought that the power supply effect on increasing the glass temperature is large, and the temperature can be increased regardless of the bubbles in the molten glass.

Next, as a comparative example 1 for the present invention described above, @1
In the figure, the defoaming tank 2 is not provided, and only the melting tank 1, the clarification tank 6, and the glass outflow part 4 are shown.
A glass melting furnace with a throat 26 provided between the melting tank 1 and the melting tank 1 was operated under the same conditions as above except that no electrode was used and the outside was clean. However, bubbles were generated in the melting tank 1 as the submerged combustion burner started operating, and the glass liquid level gradually rose. Moreover, almost no glass from the melting tank 1 moved to the fining tank 6 and the glass outflow section 4. Raw material glass 4 to 10! After continuous injection at a rate of /hr, the number of bubbles in the melting tank 1 and the glass liquid level began to increase, and the glass liquid level finally reached the bottom surface of the tile Kt of the indirect heating burner 5.
We had no choice but to cancel the operation.

Garakurobe coal of 1,200℃Kt decreases.9.

Further, as Comparative Example 2, in a glass melting furnace having the same structure as Comparative Example 1, a throat 25 was provided in the partition between the melting tank 1 and the fining tank near the glass surface, and the same operation was performed. Due to the operation of the submerged combustion burner 17, a small amount of bubbles are generated on the glass surface of the melting tank 1, and the glass with many bubbles passes through the throat 25 and is transferred to the clarification tank 6, and a large proportion of the bubbles is Despite continuous injection, no major changes were observed in the glass surface of melting tank 1, although K changed the throat position by not using glass defoaming tank 2.
Extinguishing: Directly from melting tank 1 to clarification tank 6 until 11, when 1 bubble is rarely carried out, and 1 when the input raw material is insufficiently melted.
Glass is considered to be a good item.

As described above, according to the glass melting furnace of the present invention, a defoaming tank is provided between the melting tank and the clarifying tank, and the distance aK between the melting tank and the defoaming tank is A flow path for the molten glass is formed near the liquid surface, while an F
i Since we have provided a passage for the molten glass near the lateral parts, bubbles generated on the glass surface of the melting tank will preferentially move to the defoaming tank, and in the defoaming tank, the bubbles will be removed from the glass liquid due to the difference in specific gravity. Only clear glass with few bubbles can be taken out to the fining tank. Further, the rise in the glass liquid level due to bubbles in the melting tank is suppressed. Therefore, even if a submerged combustion burner is used in the melting tank, it is possible to suppress the incorporation of bubbles into the glass as much as possible, unlike in the conventional case, and it is possible to obtain glass of excellent quality with few bubbles. Furthermore, since Honkenmei uses a submerged combustion burner in the melting tank, it is possible to significantly increase the thermal efficiency of the furnace, and as mentioned in -F, it is possible to prevent the glass liquid level from rising due to bubbles in the melting tank. Can drive.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional configuration diagram showing a conventional glass melting furnace, FIG. 2 is a cross-sectional diagram showing an outline of an embodiment of the present invention, and FIG. 3 is a cross-sectional diagram showing the installation situation of a submerged combustion burner in the present invention. . 1... Melting tank, 2... Defoaming tank, 6... Clarifying tank, 4
... Glass outflow section, 17 ... Submerged combustion burner, 22
, 24... Partition wall, 23, 25... Molten glass channel. Patent applicant: Makoto Ishizaka, Director of the Agency of Industrial Science and Technology - Designated agent: Naito, Director of the Osaka Institute of Industrial Science and Technology, Agency of Industrial Science and Technology

Claims (1)

[Claims] 1. A melting tank, a defoaming tank, a clarifying tank, and a glass outlet are arranged in this order, and a partition wall between the melting tank and the defoaming tank is provided with a glass melting tank. 1. A glass melting furnace, characterized in that a flow path for molten glass is formed near the liquid surface, and the defoaming tank is further equipped with a mid-stream combustion burner. 2. The glass melting furnace according to claim 1, wherein the melting tank is provided with a heating electric current for directly heating the glass. λ A glass indirect heating system is not provided in the upper space of the defoaming tank, as described in Claim 1 above! Glass melting furnace. 4. The defoaming W4 is provided with an electrode that directly heats the glass. The glass melting furnace described in UM1. The glass melting furnace according to claim 1, wherein the defoaming tank is provided with an electrode for heating the glass, and the upper space is provided with an indirect heating device for the glass.