JP4693178B2 - Glass melting method - Google Patents

Description

  The present invention relates to a glass melting method, and more particularly, to an improvement in a method for generating a glass melt from a glass raw material or an auxiliary raw material using a glass melting furnace equipped with a burner as a heating source.

Conventionally, as a glass melting method for generating a glass melt from a glass raw material or auxiliary material using a glass melting furnace, the glass raw material or auxiliary material charged into the furnace from the most upstream part of the glass melting furnace is used. Melting is performed by burning a burner attached to a side wall (see, for example, Patent Documents 1 to 3). However, in these conventional glass melting methods, glass raw materials and auxiliary raw materials introduced into the furnace of the glass melting furnace are melted using in-furnace radiation by burning of the burner. 1) An oxygen burner is burned as a burner. Even if it is a case, energy efficiency is poor. 2) Various materials with different melting points are included in the glass raw materials and auxiliary raw materials put into the furnace. Among these, those having a low melting point dissolve quickly. Those with a high melting point are slow to dissolve, so it is difficult to achieve homogeneous melting as a whole, and the time required for homogeneous melting is long. 3) Unmelted glass raw material etc. Therefore, there is a problem that the gas generated in the glass melt is difficult to escape and the time required for degassing is long. The conventional glass melting method has a problem that energy efficiency is low and it takes a long time to produce a desired glass melt as desired, and as a result, a large glass melting furnace is required.
JP-A-11-11953 Japanese Patent Laid-Open No. 11-11954 JP 2005-15299 A

  The problem to be solved by the present invention is to use a glass melting furnace that is energy efficient, can produce a desired glass melt as desired in a short time, and in other words, has a small installation space. It is the place which provides the glass melting method which can be performed.

The present invention that solves the above-mentioned problems uses a glass melting furnace comprising a melting zone and a clarification zone, and in the glass melting method for generating a glass melt from a glass raw material and an auxiliary raw material, the ceiling wall of the melting zone of the glass melting furnace A combustion support gas having an oxygen concentration of 90% by volume or more is supplied to an oxygen burner attached downward to burn the oxygen burner downward, and the decomposition point or boiling point of the glass raw material and auxiliary raw material is 1500 ° C. or lower; Those containing substances whose boiling point is not higher than 1500 ° C. are supplied directly to the melting zone of the glass melting furnace without being supplied into the flame of the oxygen burner, and other glass raw materials and auxiliary raw materials are not transferred by gas transportation. was dissolved was supplied under direction of the flow path in the oxygen burner flame of intervention perilla, ceiling or side wall of the refining zone of a glass melting furnace gas generated in the furnace during this According from the exhaust port formed in a part on the glass melting method characterized by discharging out of the furnace.

  Also in the glass melting method according to the present invention, a glass melt is generated from a glass raw material and auxiliary raw materials using a glass melting furnace. Such a glass melting furnace has a melting zone on the upstream side in the furnace, a clarification zone on the downstream side in the furnace, and a throat between both zones as necessary, and further on the most downstream side in the furnace Has a working zone through the throat.

In the glass melting method according to the present invention, an oxygen burner is mounted downward on the ceiling wall of the melting zone of the glass melting furnace, a combustion supporting gas having an oxygen concentration of 90% by volume or more is supplied to the oxygen burner, and the oxygen burner is directed downward. Burn with. Glass materials and auxiliary materials are a part of that, usually gas carrying with them the mixed powdered form, through the flow path in the oxygen burner, a flame burning at a downward oxygen burner Feed downward and dissolve. As such an oxygen burner itself, a known one can be used. For example, an oxygen burner described in JP-A-8-312938, JP-A-2000-55340, JP-A-2000-103656, and the like can be used. Can be diverted. In these oxygen burners, the nozzle structure at the tip is directed from the center to the outer periphery, for example, a fuel supply nozzle, a primary support gas supply nozzle, an object supply nozzle and a secondary support gas supply nozzle, Since the plurality of supply nozzles are arranged concentrically, in the glass melting method according to the present invention, the glass material and the auxiliary material are supplied through the object supply nozzle of the oxygen burner.

  If the above-mentioned oxygen burner is mounted downward on the ceiling wall of the melting zone of the glass melting furnace, and a combustion-supporting gas having an oxygen concentration of 90% by volume or more is supplied and burned downward, the temperature of the flame itself becomes high. In addition, the flame heats the molten metal surface of the glass melt generated in the furnace, and the amount of generated exhaust gas is small, so-called NOx concentration in the exhaust gas is low. When the glass raw material and the auxiliary raw material are supplied downward through the flow path in the oxygen burner, they are dissolved in a very short time. In addition, at this time, the moisture of the glass raw material and auxiliary raw material supplied downward in the high-temperature flame that burns downward evaporates all at once, and the raw material in the form of a carbonate compound or a hydroxide compound decomposes and releases gas, The amount of gas generated in the glass melt in the furnace is significantly reduced. The melting of the glass raw material and the auxiliary raw material and the clarification of the generated glass melt can be performed in a short time. As a result, it is possible to generate a desired glass melt with high energy efficiency in a short time. In addition, a glass melting furnace having a short furnace length, in other words, a small installation space can be used.

  In the glass melting method according to the present invention, an exhaust port is provided on the ceiling wall or the upper side of the clarification zone of the glass melting furnace, and the gas generated in the furnace is discharged from the exhaust port to the outside of the furnace. When the glass raw material and the auxiliary raw material are supplied downward and melted in the high-temperature flame that burns downward in the oxygen burner as described above, a correspondingly high-temperature gas is generated, but this gas passes through the melting zone in the furnace. Exhaust from the exhaust port of the clarification zone in the furnace, preferably from the exhaust port downstream of the clarification zone in the furnace, and the retained heat is used to heat or keep the surface of the glass melt generated in the furnace or furnace. This also makes it possible to clarify the glass melt more efficiently.

  In the glass melting method according to the present invention, an auxiliary oxygen burner is attached to the ceiling wall downstream of the oxygen burner attached to the ceiling wall of the glass melting furnace, and the auxiliary oxygen burner has an oxygen concentration of 90% by volume or more. It is preferable to supply gas, burn the auxiliary oxygen burner downward without supplying glass raw material and auxiliary raw material thereto, and collide the flame with the molten metal surface of the glass melt in the furnace. This is because the flame jet flows along the hot water surface and can effectively heat the hot water surface. If for some reason the amount of combustion of the oxygen burner described above is reduced, resulting in insufficient heating of the glass melt in the furnace, the auxiliary oxygen burner is burned downward and the flame is melted into the glass in the furnace. The shortage can be compensated for by colliding with the surface of the object.

  In the glass melting method according to the present invention, the decomposition point or boiling point of the glass raw material and auxiliary raw material supplied into the flame of the oxygen burner is 1500 ° C. or lower and the boiling point of the decomposition product is 1500 ° C. or lower. It is preferable to supply those having an average particle size of 1.5 times or more larger than other glass raw materials and auxiliary raw materials that are not. As described above, when a combustion supporting gas having an oxygen concentration of 90% by volume or more is supplied and the oxygen burner is burned downward, the flame usually becomes a high temperature of 2000 ° C. or higher, and glass raw materials and auxiliary raw materials are supplied into the flame. However, the temperature of the flame is usually a high temperature of 1800 ° C. or higher. Under such circumstances, glass raw materials and secondary materials having a low decomposition point or boiling point and a low boiling point of the decomposition products are kept in the form of powder having an average particle size similar to that of glass raw materials and secondary materials that are not so. When supplied into the flame of the burner, the former glass raw material and auxiliary raw material are not evaporated and vitrified, and the vitrification yield is lowered accordingly. In order to prevent such inconvenience, the glass raw material and the auxiliary raw material are divided into those having a decomposition point or boiling point of 1500 ° C. or less and a decomposition product having a boiling point of 1500 ° C. or less, and those not so, and the former being the latter Is supplied into the flame of the oxygen burner in a form having an average particle size larger than 1.5 times, that is, in a form that does not easily evaporate. The decomposition point or boiling point is 1500 ° C. or lower and the decomposition product has a boiling point of 1500 ° C. or lower means that the main component is such a raw material, but not (1500 ° C. In the case of containing a large amount of (super), the dissolution time becomes long, so that the decomposition point or boiling point is 1500 ° C. or less and the decomposition product has a boiling point of 1500 ° C. or less of 60% by mass or more, preferably 70% by mass or more. It only has to be included.

Among glass raw materials and auxiliary raw materials, for example, silica and alumina corresponding to glass raw materials have a boiling point of 2000 ° C. or higher, so aluminum hydroxide (Al (OH) ₃ ), calcium carbonate (CaCO ₃ ) and slaked lime (Ca (OH) ₂ ) has a decomposition point of 1500 or less, but since these decomposition products (Al ₂ O ₃ or CaO) have a boiling point of 2000 ° C. or higher, the above glass raw materials are in the form of a powder and an oxygen burner. Supply during the flame. However, sodium carbonate corresponding to the glass raw material, and also all correspond to the auxiliary raw materials, but the oxidizing point of sodium nitrate, the clarifying agent of sodium sulfate, anhydrous arsenous acid and antimony oxide have a decomposition point or boiling point of 1500 ° C. or less. And the boiling point of the decomposition product is 1500 or less, the glass raw material and auxiliary raw materials containing these are those whose average particle size is 1.5 times or more larger than the glass raw material that is not, preferably the average particle size Is supplied as 1.5 to 5 times larger in the flame of the oxygen burner.

  FIG. 1 exemplifies a temperature rise situation when a mixture of glass raw materials and auxiliary raw materials for producing soda-lime glass is pulverized and sized to various average particle diameters and put into an atmosphere of 2000 ° C. It is a graph to do. The horizontal axis indicates the relative elapsed time after injection, and the vertical axis indicates the temperature. In FIG. 1, 1 has an average particle size of 0.10 mm, 2 has an average particle size of 0.15 mm, 3 is an average particle diameter of 0.20 mm, 4 is an average particle diameter of 0.30 mm, 5 is an average particle diameter of 0.45 mm, and 6 is an average particle diameter of 1.0 mm. Also from FIG. 1, it can be seen that when the average particle diameter is 1.5 times, the temperature for the same relative elapsed time is lowered by about 300 ° C., as indicated by the dashed arrow in FIG.

In the glass melting method according to the present invention, among the glass raw material and the auxiliary raw material, the decomposition point or boiling point is not higher than 1500 ° C. and the boiling point of the decomposition product is not higher than 1500 ° C. in order to prevent a reduction in yield, feed them directly to the melting zone of the glass melting furnace without supplying the flame of the oxygen burner.

Further, in the glass melting method according to the present invention, the above-described oxygen burner and / or auxiliary oxygen burner is burned at a value larger than the theoretical oxygen ratio, and the nitrogen oxide generated by such combustion is supplied into the downstream furnace. It is preferable that the remaining unburned gas is reduced with the cracked gas and its decomposition gas, and further subjected to secondary combustion with oxygen and / or air supplied into the furnace on the downstream side, and then discharged outside the furnace. Oxygen burner and auxiliary oxygen burner due to N ₂ contained in the air used to convey the glass raw material and auxiliary raw material gas, and further N ₂ contained in the combustion supporting gas. Is burned at a high temperature, so-called NOx is generated. In order to prevent such NOx from being discharged out of the furnace as it is, the oxygen burner and / or the auxiliary oxygen burner is first set to a value larger than the theoretical oxygen ratio in order to prevent coloring of the glass, for example, 1.1 to NOx generated by combustion in 1.2 is reduced to N ₂ by reducing it with a fuel such as methane or propane supplied to the downstream furnace and a cracked gas such as H ₂ or CO decomposed, and finally remains. N ₂ , CO ₂ , H ₂ O generated by the secondary combustion of the unburned fuel and cracked gas to the outlet outlet with oxygen and / or air supplied into the further downstream furnace and thus processing Such exhaust gas is discharged from the exhaust port to the outside of the furnace.

  Furthermore, in the glass melting method according to the present invention, a thermocouple is provided in the lower part of the glass melt in the furnace or in the upper part of the hearth wall of the glass melting furnace, and based on the temperature detected by the thermocouple, It is preferable to control the supply amount, the supply amount of the auxiliary material, the combustion amount of the oxygen burner and / or the combustion amount of the auxiliary oxygen burner. In the glass melting method according to the present invention as described above, in order to control the supply amount of the glass raw material and the auxiliary raw material, the combustion amount of the oxygen burner and the auxiliary oxygen burner, and perform the glass melting as set, Although it is important to measure the temperature of the glass melt, in order to measure such temperature, for example, a thermocouple is inserted into the furnace from the ceiling wall or upper side of the glass melting furnace, and the tip of the glass melt is placed in the glass melt. Soaking in is difficult to damage the thermocouple protection tube at the interface between gas and liquid, which is a major problem in durability. Therefore, the thermocouple is inserted from the hearth wall or the lower part of the side wall, and the tip is faced to the upper part of the hearth wall or the lower part of the glass melt is overcome. Based on the temperature detected by the thermocouple, the supply amount and the combustion amount are controlled as described above. In view of its nature, such a thermocouple preferably has its tip directly under the oxygen burner, and is preferably provided not only in the dissolution zone but also in the clarification zone.

  In the glass melting method according to the present invention, an oxygen burner having a primary support gas supply system and a secondary support gas supply system independently is used, and the oxygen ratio by both supply systems of the oxygen burner is used. Is preferably controlled based on the type of glass raw material and auxiliary raw material supplied to the oxygen burner and / or the temperature of the glass melt in the furnace. This is because the flame shape and the like of the oxygen burner are optimally maintained in relation to the types of glass raw materials and auxiliary raw materials supplied to the oxygen burner, and further to the temperature of the glass melt generated in the furnace.

  According to the glass melting method according to the present invention, when generating a glass melt from a glass raw material or an auxiliary raw material, energy efficiency is good, a desired glass melt can be generated in a short time, and a small size, In other words, there is an effect that a glass melting furnace with a small installation space can be used.

  FIG. 2 is an overall view schematically showing in part a longitudinal section an implementation state of the glass melting method according to the present invention. Here, for convenience, a plurality of implementation states as described below are shown at the same time. The glass melting furnace 11 used in the illustrated glass melting method includes a melting zone 12 on the upstream side in the furnace, a clarification zone 13 on the downstream side in the furnace, and a working zone on the most downstream side in the furnace. 14 is provided. However, the boundary between the dissolution zone 12 and the fining zone 13 is not shown here because it varies depending on the composition of the raw material, the average particle diameter, the operating conditions, and the like. An oxygen burner 21 is attached downward on the ceiling wall upstream of the dissolution zone 12, and an auxiliary oxygen burner 22 is attached downward on the ceiling wall downstream of the dissolution zone 12. An exhaust port 31 is provided in the ceiling wall. The oxygen burner 21 and the auxiliary oxygen burner 22 are attached to the ceiling wall via the cylinder mechanisms 23 and 24, and can be moved up and down, and between those tip portions and the molten metal surface of the glass melt A in the furnace. The distance is variable.

  The oxygen burner 21 has a plurality of supply nozzles in the order of a fuel supply nozzle, a primary combustion support gas supply nozzle, an object to be processed (glass raw material, etc.) supply nozzle, and a secondary combustion support gas supply nozzle. It consists of what was arranged concentrically, and the flow path of primary combustion support gas and the flow path of secondary combustion support gas are independent. The oxygen burner 21 is supplied with combustion-supporting gas having an oxygen concentration of 90% by volume or more from the adsorption-type oxygen generator 41 through the combustion control unit 42, and from the fuel tank 43 through the combustion control unit 42. Fuel gas is supplied. Further, a gas conveyance system 51 is connected to the oxygen burner 21 so that a powdery glass mixed raw material obtained by mixing glass raw materials and auxiliary raw materials is supplied by gas conveyance. A compressor 52 with a dryer is connected to the upstream side of the gas transfer system 51, and a raw material supply system 61 is connected in the middle thereof. The raw material supply system 61 includes raw material storage hoppers 62, 63, quantitative cutting devices 64, 65 connected to the hoppers 62, 63, a mixer 66 connected to the quantitative cutting devices 64, 65, A fixed amount supply device 67 connected to the mixer 66 is provided. An exhaust system 32 is connected to the exhaust port 31, and a cooling tower 71, a dust collector 72, a suction fan 74, and a chimney 75 are connected to the exhaust system 32 in this order.

  In the glass melting method based on FIG. 2 described above, the fuel gas and the oxygen concentration are 90% by volume or more through the combustion control unit 42 to the oxygen burner 21 mounted downward on the ceiling wall of the glass melting furnace 11 upstream of the melting zone 12. The combustion gas is supplied to burn the oxygen burner 21 downward, and the powdery glass raw material and auxiliary raw material stored in the hoppers 62 and 63 are fed into the raw material supply system 61 and the gas transport system. By gas conveyance via 51, the object is supplied and dissolved downward through the above-mentioned object supply nozzle in the oxygen burner 21, and the exhaust gas generated at this time is discharged from the exhaust port 31 through the exhaust system 32. According to the glass melting method according to the present invention described above, it takes tens of minutes to several hours in the conventional glass melting method in which the glass raw material and the auxiliary raw material charged into the furnace are melted using the in-furnace radiation due to burner combustion. The dissolution time that has been achieved can be from a few seconds to a few minutes. Further, in the glass melting method based on FIG. 2 described above, the fuel control is performed without supplying the glass raw material and the auxiliary raw material to the auxiliary oxygen burner 22 mounted downward on the ceiling wall downstream of the melting zone 12 in the glass melting furnace 11. When fuel gas and combustion support gas having an oxygen concentration of 90 vol% or more are supplied through the unit 42 and the auxiliary oxygen burner 22 is burned downward and the flame collides with the molten metal surface of the glass melt A in the furnace, Even if the ratio of the combustion amount / raw material supply amount of the oxygen burner on the side is lowered, the refining time which has taken several hours to several tens of hours in the above-described conventional glass melting method can be made tens of minutes to several hours. .

  Further, in the glass melting method based on FIG. 2 described above, a hopper 63 is stored that contains 60% by mass of a glass raw material and a secondary raw material whose decomposition point or boiling point is 1500 ° C. or lower and whose decomposition product has a boiling point of 1500 ° C. or lower. In addition, other glass raw materials and auxiliary raw materials that are not so are stored in the hopper 62, and the average particle diameter is 1.5 times larger than the one stored in the hopper 62 than that stored in the hopper 62. You can also. In such a glass melting method, the vitrification rate that was 80% by mass when the hoppers 62 and 63 were stored and melted with an average particle diameter of 0.1 mm was the same as that stored in the hopper 62. If the hopper 63 stores and dissolves the one having an average particle diameter of 0.15 mm, the hopper 63 can be made 90 mass%. When 20 mm is stored and dissolved, it can be made 96% by mass.

  Similarly, in the glass melting method based on FIG. 2 described above, the hopper 63 contains 60% by mass of a glass raw material and an auxiliary raw material whose decomposition point or boiling point is 1500 ° C. or lower and whose decomposition product has a boiling point of 1500 ° C. or lower. The other glass raw materials and auxiliary raw materials that are not stored in the hopper 62 and stored in the hopper 63 are stored in the flame of the oxygen burner 21 without passing through the raw material supply system 61 and the gas transport system 51. It is also possible to supply directly to the upstream portion of the melting zone 12 of the glass melting furnace 11 via another raw material supply system 61a without being supplied to. In such a glass melting method, the vitrification rate which was 80% by mass when the one having an average particle diameter of 0.1 mm stored in the hoppers 62 and 63 was supplied into the flame of the oxygen burner 21 and melted, If the material stored in the hopper 62 is directly supplied to the melting zone 12 of the glass melting furnace 11 and melted in the same manner, it can be 90% by mass.

  Further, in the glass melting method based on FIG. 2 described above, the oxygen burner 21 and the auxiliary oxygen burner 22 are burned at a value larger than the theoretical oxygen ratio, for example, 1.1 to 1.2, and nitrogen oxides generated by such combustion are removed. The fuel supplied to the downstream furnace via the combustion control unit 42 and the fuel supply system 44 and its decomposition gas are reduced, and the remaining unburned fuel is further supplied to the downstream furnace via the air supply system 45. After being subjected to secondary combustion with the air supplied to the exhaust gas, it can be discharged from the exhaust port 31 through the exhaust system 32. According to such a glass melting method, the NOx concentration can be reduced to 120 ppm in the exhaust gas that was 400 ppm (converted to an oxygen concentration of 15%) particularly when such combustion, reduction, and secondary combustion are not performed.

  Furthermore, in the glass melting method based on FIG. 2 described above, a thermocouple 81 is provided along the hearth surface facing the lower part of the glass melt A immediately below the oxygen burner 21, and based on the temperature detected by the thermocouple 81. The supply amount of the glass raw material and the auxiliary raw material is controlled by the quantitative supply device 67 (Y in FIG. 2), and the combustion amount of the oxygen burner 21 and the auxiliary oxygen burner 22 is controlled by the combustion control unit 42 (in FIG. 2). X) can also be. Similarly, in the glass melting method based on FIG. 2 described above, an oxygen burner 21 having a primary support gas supply system 46 and a secondary support gas supply system 47 independently is used. 2 is controlled based on the temperature of the glass melt detected by the thermocouple 81 (X in FIG. 2), or facing the lower part of the glass melt A in the refining zone 13 in the furnace. Another thermocouple 82 is provided on the hearth wall, and the same control can be performed based on the temperature of the glass melt detected by the thermocouple 82 (Z in FIG. 2). According to such a glass melting method, the temperature of the glass melt in the furnace can be continuously and accurately detected, so that the combustion of the oxygen burner and the glass raw material are immediately performed without causing a time lag based on the detected temperature. Etc. can be appropriately controlled.

The glass which illustrates the change of the temperature rising condition by the average particle diameter of a glass raw material and an auxiliary raw material in the glass melting method which concerns on this invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Glass melting furnace 12 Melting zone 13 Clarification zone 21 Oxygen burner 22 Auxiliary oxygen burner 31 Exhaust port 32 Exhaust system 41 Adsorption-type oxygen generator 42 Combustion control unit 44 Fuel supply system 51 Gas conveyance system 61, 61a Raw material supply system 62, 63 Hopper 64, 65 Fixed amount cutting device 67 Fixed amount supply device 71 Cooling tower 72 Dust collector 81, 82 Thermocouple

Claims (5)

In a glass melting method using a glass melting furnace having a melting zone and a clarification zone to generate a glass melt from a glass raw material and an auxiliary raw material, an oxygen concentration is attached to an oxygen burner mounted downward on the ceiling wall of the melting zone of the glass melting furnace. Combustion gas of 90% by volume or more is supplied and the oxygen burner is burned downward. Among the glass raw material and auxiliary raw material, the decomposition point or boiling point is 1500 ° C. or lower and the decomposition product has a boiling point of 1500 ° C. or lower. a substance intended to include supplies directly to the melting zone of the glass melting furnace without supplying into the oxygen burner flame, as well as a glass raw material and auxiliary materials otherwise to through the flow path in the oxygen burner by gas carrying was dissolved was supplied under orientation in its flame, the exhaust gas generated in the furnace when the ceiling wall or the exhaust port formed in a side wall upper portion of the refining zone of a glass melting furnace out of the furnace Glass melting method characterized by.   Further, a supplementary oxygen burner having an oxygen concentration of 90% by volume or more is supplied to an auxiliary oxygen burner mounted downward on the ceiling wall on the downstream side of the oxygen burner of the glass melting furnace without supplying glass raw materials and auxiliary raw materials. The glass melting method according to claim 1, wherein the burner is burned downward and the flame collides with the molten metal surface of the glass melt in the furnace. An oxygen burner and / or an auxiliary oxygen burner is burned at a value larger than the theoretical oxygen ratio, and nitrogen oxides generated by such combustion are reduced by the fuel supplied to the downstream furnace and its cracked gas, and remaining unburned The glass melting method according to claim 1 or 2 , wherein the portion is subjected to secondary combustion with oxygen and / or air supplied into the further downstream furnace and then discharged to the outside of the furnace. A thermocouple is provided in the lower part of the glass melt in the furnace or in the upper part of the hearth wall of the glass melting furnace, and based on the temperature detected by the thermocouple, the supply amount of the glass raw material, the supply amount of the auxiliary raw material, the oxygen burner The glass melting method according to any one of claims 1 to 3 , wherein the amount of combustion and / or the amount of combustion of the auxiliary oxygen burner is controlled. A glass raw material that uses an oxygen burner having a primary combustion support gas supply system and a secondary combustion support gas supply system independently, and supplies the oxygen burner with an oxygen ratio from both supply systems of the oxygen burner. The glass melting method according to any one of claims 1 to 4 , wherein the glass melting method is controlled based on the type of the auxiliary raw material and / or the temperature of the glass melt in the furnace.

Images