JP2018035990A - melting furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a melting furnace that can melt a melting object with high-heat efficiency while generating a homogeneous and fine melting product material by preferably convecting melting object in a dissolver.SOLUTION: A melting furnace includes: a combustion device N for heating a melting object G loaded into a dissolver 11 with a flame K formed in a combustion space S in an upper part of the dissolver 11; a gas injection hole 30a for injecting a gas into the melting object G loaded into the dissolver 11; and a premixed gas introduction mechanism for leading a premixed gas premixed an oxygen-containing gas A with a fuel gas F with an air ratio within a combustible range into the gas injection hole 30a.SELECTED DRAWING: Figure 1

Description

  The present invention includes a combustion device that heats a melting target charged in a melting tank with a flame that forms in a combustion space above the melting tank, and jets gas into the melting target charged in the melting tank The present invention relates to a melting furnace having a gas ejection hole.

  Conventionally, as a melting furnace, for example, as shown in Patent Document 1, a plurality of burners and a heat storage chamber are provided on each of a pair of side walls along a traveling direction of a melting target charged in a melting tank. It is known that a burner provided on the other side wall and a burner provided on the other side wall are alternately burned, that is, a so-called alternating combustion mode is used to dissolve a melting object.

Here, in the melting furnace, in order to efficiently dissolve the melting object and obtain a homogeneous and clear melting product, the melting object (or a mixture of the melting object and the melting product in which the melting object is dissolved) is used. It is preferable to convection in the dissolution tank.
Therefore, for example, as shown in Patent Document 2, a gas ejection hole is provided in the lower part of the dissolution tank, and air is ejected from the gas ejection hole into the dissolution object of the dissolution tank, and a large number of objects are dissolved inside the dissolution object. There is known a technique for generating a bubble and convection of an object to be dissolved by the bubble.

  As another technique, as shown in Patent Document 3, a submerged combustion burner is provided in a state in which a combustion flame is formed from the lower part of the dissolution tank to the inside of the dissolution tank, and is formed by the submerged combustion burner. There is known a melting furnace in which convection is generated in an object to be melted by a combustion flame.

JP 2009-243853 A JP 08-297198 A JP 2014-189429 A

In the technique disclosed in Patent Document 2, the object to be melted in the melting tank can be convected by air. However, since the air lowers the temperature in the furnace, the thermal efficiency is lowered, and the improvement is achieved. There was room. Incidentally, the technique disclosed in Patent Document 2 includes an electric heater that preheats the air sent to the dissolution tank. However, when the electric heater preheats, electric power is consumed, and the total energy efficiency is reduced. .
On the other hand, in the technique disclosed in Patent Document 3, the object to be dissolved is convected by the combustion flame of the submerged combustion burner. However, when the combustion flame of the submerged combustion burner is formed inside the object to be melted in this way, there is a possibility that a hollow cavity that conforms to the shape of the flame may be formed at the site where the combustion flame is formed. In such a situation, the combustion flame and the combustion exhaust gas will escape, so that the convection of the object to be dissolved cannot be sufficiently promoted and the object to be dissolved cannot be sufficiently heated by the combustion flame. There was room for improvement in terms of thermal efficiency.

  The present invention has been made in view of the above-mentioned problems, and the object thereof is to dissolve the object to be dissolved with high thermal efficiency while generating a homogeneous and clear object to be dissolved by convection the object to be dissolved in the dissolution tank. An object of the present invention is to provide a melting furnace capable of melting an object.

A melting furnace for achieving the above object comprises a combustion device that heats a melting target charged in a melting tank by a flame that forms in a combustion space above the melting tank, and the melting target charged in the melting tank A melting furnace having a gas ejection hole for ejecting gas into an object, the characteristic configuration of which is
There exists a premixed gas introduction mechanism which leads the premixed gas which premixed oxygen-containing gas and fuel gas by the air ratio of the combustible range to the said gas ejection hole.

According to the above characteristic configuration, the premixed gas in which the oxygen-containing gas and the fuel gas are premixed at an air ratio in the combustible range is ejected from the gas ejection hole provided in the dissolution tank into the object to be dissolved. With the gas, the dissolution target dissolved in the dissolution tank can be convected well, so that the entire dissolution target can be dissolved substantially uniformly, and a homogeneous and clear dissolution target can be obtained.
In addition, the temperature of the melting tank is raised to the flammable temperature range by the flame formed by the combustion device, so that the premixed gas having an air ratio in the flammable range ejected from the bottom of the melting tank is Compared with the case where air is introduced, the temperature drop of the object to be dissolved can be reduced and the thermal efficiency can be improved.
Furthermore, according to the configuration in which the premixed gas is ejected to the dissolution tank in this way, the combustion flame is formed at the bottom of the dissolution tank by the submerged burner by appropriately adjusting the ejection speed for ejecting the premixed gas. Compared with the case where it does, the residence time in the melt | dissolution target object of combustion gas can be taken long, and the further improvement of thermal efficiency can be anticipated.
As described above, it is possible to realize a melting furnace capable of melting a melting target object with high thermal efficiency while generating a homogeneous and clear melting target object by successfully convection of the melting target object in the melting tank.

Further features of the melting furnace
The premixed gas introduction mechanism includes an air ratio adjusting unit that adjusts an air ratio of the premixed gas guided to the gas ejection hole.

The melting furnace can realize the heating / melting state according to the production amount and the type of the melting object by appropriately adjusting the air ratio of the melting tank. For example, when the melting object is glass, transparent glass can be produced by adjusting the melting tank to an oxidizing atmosphere, and colored glass can be produced by adjusting the melting tank to a reducing atmosphere.
According to the above characteristic configuration, the air ratio adjusting unit of the premixed gas introduction mechanism adjusts the air ratio of the premixed gas guided to the gas ejection holes, so that it appropriately burns inside the dissolution target in the melting tank. However, since the combustion can be realized in various oxidation-reduction atmospheres from the oxidation atmosphere to the reduction atmosphere, the combustion state according to the production amount and the type of the object to be dissolved can be appropriately realized.
Moreover, such adjustment can be realized not only from the combustion space in which the flame is formed, but also from the inside of the object to be melted. Can produce no uniform product.

Further features of the melting furnace
Introduced from all of the plurality of gas ejection holes to the dissolution tank with respect to the maximum input heat amount related value related to the maximum input heat quantity of the premixed gas introduced into the dissolution tank from all of the plurality of gas ejection holes. When the premixed input heat amount ratio, which is the ratio of the partial input heat amount of the premixed gas, is equal to or less than a specific heat amount ratio determination threshold predetermined for each melting furnace,
The air ratio adjusting unit is in the point of setting the air ratio of the premixed gas to the lower side.

As shown in the graph of FIG. 4, the inventors of the present application have intensively studied, and as shown in the graph of FIG. 4, the maximum input heat amount related to the maximum input heat amount of the premixed gas introduced into the dissolution tank from all of the plurality of gas ejection holes. A specific heat amount ratio determination threshold in which a premixed input heat amount ratio, which is a ratio of the partial input heat amount of the premixed gas introduced from all of the plurality of gas ejection holes to the melting tank, is determined in advance for each melting furnace. In the following cases, it has been found that the heat efficiency is higher when the air ratio of the premixed gas introduced from the plurality of gas ejection holes is smaller.
According to the above characteristic configuration, the plurality of gas ejection holes are introduced into the dissolution tank from the plurality of gas ejection holes with respect to the maximum input heat amount related value related to the maximum input heat quantity of the premixed gas introduced into the dissolution tank from all of the plurality of gas ejection holes. When the premixed input heat amount ratio, which is the ratio of the partial input heat amount of the premixed gas, is equal to or less than a specific heat amount ratio determination threshold, the air ratio adjustment unit sets the air ratio of the premixed gas to the lower side, The thermal efficiency can be further improved.
Incidentally, the “maximum input heat amount related value related to the maximum input heat amount of the premixed gas introduced into the dissolution tank from all of the plurality of gas ejection holes” is, for example, introduced into the dissolution tank from all of the plurality of gas ejection holes. This means a heat quantity of about 80% of the maximum input heat quantity of the possible premixed gas. The value related to the maximum input heat amount is not limited to about 80%, and is a value of about 80% to 100% of the maximum input heat amount of the premixed gas that can be introduced into the dissolution tank from all of the plurality of gas ejection holes. Is included.
The “specific heat ratio determination threshold value” is a threshold value that is individually determined for each melting furnace based on the size of the melting furnace and the like, is determined by performing a test or the like in advance for each melting furnace, and is stored in a storage unit or the like. Value.

As a melting furnace that has been explained so far,
The heat amount ratio determination threshold is a value determined based on the maximum input heat amount related value, and it is preferable that a storage unit for storing the value in advance is provided.

Further features of the melting furnace
A plurality of the gas ejection holes are provided at the bottom of the dissolution tank,
Each of the ejection amounts of the premixed gas ejected from the plurality of gas ejection holes is provided with an ejection amount adjusting section that can be adjusted individually.

  According to the above characteristic configuration, the ejection amount adjustment unit is configured to be able to individually adjust each of the ejection amounts of the premixed gas from the gas ejection holes provided at the bottom of the dissolution tank. The convection state of the object to be melted in the melting tank can be appropriately adjusted to an appropriate one in accordance with the type, production amount, melting furnace type, and the like.

Further features of the melting furnace
A plurality of the gas ejection holes are provided at the bottom of the dissolution tank,
The ejection direction of at least a pair of the gas ejection holes among the plurality of gas ejection holes is in a diffusion direction in which the premixed gas ejected from the gas ejection holes is diffused above the plurality of gas ejection holes. It is in the point provided for.

As in the above characteristic configuration, the diffusion direction in which the premixed gas ejected from each gas ejection hole is diffused in the ejection direction of at least one pair of gas ejection holes among the plurality of gas ejection holes above the plurality of gas ejection holes. By providing for the convection, it becomes possible to promote convection by bubbles of the premixed gas in a wider area in a plan view of the dissolution tank.
Further, in the plan view of the dissolution tank, the premixed gas is ejected to a wider area, and the object to be dissolved can be heated by the combustion of the premixed gas, so that the entire object to be dissolved can be appropriately heated. Thermal efficiency can be improved.

Further features of the melting furnace
A plurality of the gas ejection holes are provided at the bottom of the dissolution tank,
The ejection direction of at least one pair of the gas ejection holes among the plurality of gas ejection holes is in a convergence direction in which the premixed gas ejected from the gas ejection holes converges above the plurality of gas ejection holes. It is in the point provided for.

From the viewpoint of promoting the convection of the dissolution target in the dissolution tank, it is preferable that the bubbles formed in the dissolution target of the premixed gas ejected from the gas ejection holes have a large diameter.
However, when increasing the amount of premixed gas ejected from one gas ejection hole to form a large-diameter bubble, assuming that the diameter of the gas ejection hole is constant, the ejection speed of the premixed gas increases. Therefore, it is not always possible to form a large diameter bubble. For example, when the ejection speed of the premixed gas is equal to or higher than a predetermined speed, the ejected premixed gas forms a gas flow path continuously up to the upper part of the dissolution tank without forming bubbles, so that convection is promoted. There is a possibility that it may become an unpreferable state.
As in the above characteristic configuration, the convergence direction in which the premixed gas ejected from each gas ejection hole converges in the ejection direction of at least a pair of the gas ejection holes among the plurality of gas ejection holes above the plurality of gas ejection holes. By providing it toward the surface, the bubbles formed in the object to be dissolved are joined by at least the premixed gas ejected from the pair of gas ejection holes without increasing the gas ejection speed from the gas ejection holes more than necessary. , Large diameter bubbles can be formed, and convection can be promoted by the large diameter bubbles.

Further features of the melting furnace
The premixed gas introduction mechanism includes a premixed gas flow pipe that flows through the premixed gas and is connected to the gas ejection hole,
The inner diameter of the premixed gas flow pipe is less than the extinguishing distance of the fuel gas.

  According to the above characteristic configuration, the fuel gas flowing through the premixed gas flow pipe is prevented from backfire, and the premixed gas can be safely ejected from the gas ejection holes.

II sectional view of the melting furnace shown in FIG. 2, which is the melting furnace according to the embodiment Plan sectional drawing of the melting furnace concerning an embodiment III-III sectional view of the melting furnace according to the embodiment, which is the melting furnace shown in FIG. Graph showing thermal efficiency when changing the premixed input heat rate for each air ratio Longitudinal sectional view of a melting furnace according to another embodiment Longitudinal sectional view of a melting furnace according to another embodiment

As shown in FIGS. 1 to 3, the melting furnace 100 according to the embodiment of the present invention generates a homogeneous and clear melted product with good convection by melting the melted object in the melting tank 11 with high thermal efficiency. The present invention relates to a melting furnace 100 that can melt a melting object.
Hereinafter, the melting furnace 100 will be described with reference to FIGS.

As shown in FIGS. 1 to 3, the melting furnace 100 is a melting furnace for melting a glass raw material G (an example of an object to be melted), and is configured as a so-called through-port type melting furnace. If it adds, the inside of the glass raw material G thrown into the melting tank 11 will be provided with the combustion apparatus N which heats the glass raw material G thrown into the melting tank 11 with the flame which forms in the combustion space S of the upper part of the melting tank 11. A gas ejection hole 30a for ejecting gas to the gas is provided, and a premixed gas obtained by premixing oxygen-containing gas A (for example, air) and fuel gas F (for example, city gas 13A) at an air ratio in the combustible range is provided. A premixed gas introduction mechanism that leads to the ejection holes 30a is provided.
The melting furnace 100 includes a rectangular furnace body 10 having a longitudinal direction (a direction along an arrow X in FIG. 2) in a plan view. Above the melting furnace body 10, a glass raw material G and A melting tank 11 for transferring the molten glass G that has been melted is provided, and a combustion space S is formed above the melting tank 11.

In the plan view, the melting tank 11 is provided with a receiving port (not shown) for receiving the glass raw material G on the wall surface 11a at one end in the longitudinal direction, and the molten glass G on the wall surface 11b at the other end in the longitudinal direction. Is provided with a discharge port (not shown).
A pair of heat storage chambers T provided with heat storage bricks and the like are provided along the longitudinal direction of the melting tank 11 on the side of the melting tank 11, and the pair of heat storage chambers T and the melting furnace body 10 are provided. The combustion space S is communicatively connected by a gas passage 12 through which gas flows. In addition, the gas flow path 12a which connects one heat storage chamber T and the combustion space S of the melting furnace main body 10, and the gas flow path 12b which connects the other heat storage chamber T and the combustion space S of the melting furnace main body 10 are The flow path opening ends facing both combustion spaces S are provided in a state of facing each other, and further, a gas flow path 12a connecting one heat storage chamber T and the combustion space S of the melting furnace body 10; A plurality of sets of gas passages 12 b that connect the other heat storage chamber T and the combustion space S of the melting furnace body 10 are provided along the longitudinal direction of the melting tank 11.

As shown in FIG. 1, the melting furnace 100 according to this embodiment includes an oxygen-containing gas flow path L0 that flows through an oxygen-containing gas A that is pumped by a fan F1 and an exhaust gas E, as shown in FIG. Exhaust gas discharge path L3 for discharging to the outside, flow path switching valve V0, first flow path L1 connecting flow path switching valve V0 and one heat storage chamber T, flow path switching valve V0 and the other heat storage chamber T And a flow switching valve V0 connects the oxygen-containing gas flow path L0 to the first flow path L1 and the exhaust gas discharge path L3 to the second flow path L2. The first flow state to be connected and the second flow state to connect the oxygen-containing gas flow path L0 to the second flow path L2 and connect the exhaust gas discharge path L3 to the first flow path L1 can be switched. It is configured.
With this configuration, operation control for controlling the switching of the oxygen-containing gas flow path L0, the exhaust gas discharge path L3, the first flow path L1, the second flow path L2, the flow path switching valve V0, and the flow path switching valve V0. (Not shown) supplies the oxygen-containing gas A that has passed through one of the heat storage chambers T to the combustion space S through the gas flow passage 12a, and the exhaust gas E from the combustion space S through the gas flow passage 12b. And the oxygen-containing gas A that has passed through the other heat storage chamber T is supplied to the combustion space S through the gas flow passage 12b. At the same time, the second exhaust state where the exhaust gas E from the combustion space S is passed through one heat storage chamber T via the gas passage 12a and then discharged to the outside is switched.

Between a gas flow path 12 a that connects one heat storage chamber T and the combustion space S of the melting furnace body 10, and a gas flow path 12 b that connects the other heat storage chamber T and the combustion space S of the melting furnace body 10. Is provided with a combustion device N that forms a flame K from the flow path portion toward the combustion space S.
If a description is added, the said combustion apparatus N will project the top part in which the fuel gas injection part (not shown) which injects the fuel gas F to the combustion space S is formed in the flow-path part of the gas flow path 12 An elevating mechanism (not shown) is provided that switches between the posture and a retraction posture that retreats from the flow path portion of the gas passage 12 to the outside of the flow path. The operation control unit (not shown) sets the combustion device N provided in the gas flow path 12 through which the oxygen-containing gas A flows, of the combustion device N, to a projecting posture, and allows the gas flow through which the exhaust gas E flows. The combustion device N provided in the flow path 12 is set to a retreat posture, and a flame K is formed in the combustion device N in a protruding posture. That is, the operation control unit alternates between a protruding posture and a retracting posture of the combustion apparatus N in response to switching between the first flow state and the second flow state of the oxygen-containing gas A and the exhaust gas E. Perform combustion. When the glass raw material G is melted as an object to be melted by performing the alternating combustion, the inside of the melting furnace body 10 is maintained at a temperature of about 1500 ° C., and the glass raw material G is melted.

Now, the melting furnace 100 according to the embodiment melts the glass raw material G with high thermal efficiency while convectioning the glass raw material G and the molten glass G in the melting tank 11 well to produce a homogeneous and clear molten glass G. Therefore, a premixed gas introduction mechanism is provided that guides a premixed gas in which the oxygen-containing gas A and the fuel gas F are premixed at an air ratio in the combustible range to the gas ejection holes 30a. Incidentally, in this embodiment, a plurality of gas ejection portions 30 having one gas ejection hole 30a are provided in such a form that the gas ejection holes 30a face the bottom of the dissolution tank 11, and a plurality of gas ejections are provided. A configuration in which a premixed gas is supplied to each of the sections 30 is adopted.
When the description is added, as shown in FIGS. 1 and 2, the oxygen-containing gas passage L4 through which the oxygen-containing gas A flows, the fuel gas passage L5 through which the fuel gas F flows, and the oxygen-containing gas passage Premixed gas passages L6 and L7 are provided to connect the downstream portion of the passage L4 and the fuel gas passage L5 and the gas ejection portion 30, and in this embodiment, The premixed gas flow paths L6 and L7 (an example of the premixed gas flow pipe) are an upstream premixed gas flow path L6 through which the premixed gas flows on the upstream side and the upstream premixed gas flow path. The plurality of downstream premixed gas flow paths L7 branch from the path L6, and each of the plurality of downstream premixed gas flow paths L7 communicates with each of the plurality of gas ejection portions 30. It is connected.

Further, the oxygen-containing gas passage L4 is provided with a first flow control valve V1 for controlling the flow rate of the oxygen-containing gas A flowing through the oxygen-containing gas passage L4. Is provided with a second flow rate control valve V2 for controlling the flow rate of the fuel gas F flowing through the fuel gas flow path L5, and each of the plurality of downstream premixed gas flow paths L7 includes the downstream side. A third flow rate control valve V3 for controlling the flow rate of the premixed gas flowing through the premixed gas flow path L7 is provided.
And the valve opening degree of the 1st flow control valve V1, the 2nd flow control valve V2, and the 3rd flow control valve V3 is controlled by the operation control part which is not illustrated, and the 1st flow control valve V1 and the 2nd flow control By controlling the valve opening degree of the valve V2, the air ratio of the supplied premixed gas is appropriately adjusted to the air ratio in the combustible range. Further, by controlling the opening degree of the plurality of third flow rate control valves V3 separately, each of the ejection amounts of the premixed gas ejected from the plurality of gas ejection holes 30a is adjusted individually.
That is, the first flow control valve V1, the second flow control valve V2, and the operation control unit function as an air ratio adjustment unit, and the third flow control valve V3 and the operation control unit function as an ejection amount adjustment unit. Furthermore, the oxygen-containing gas passage L4, the fuel gas passage L5, the premixed gas passages L6 and L7, the first flow control valve V1, the second flow control valve V2, the third flow control valve V3, and the operation The control unit functions as a premixing introduction mechanism.

In addition, in the said embodiment, as shown in FIGS. 1-3, the gas ejection hole 30a provided in each of the several gas ejection part 3 is the receiving port (not shown) of the glass raw material G in the melting tank 11. As shown in FIG. ) Along the direction (direction along arrow Z in FIGS. 1, 2, and 3) perpendicular to the flow direction (direction along arrow X in FIGS. 1, 2, and 3) from the discharge port (not shown) as a whole. In the form of rows, they are provided at equal intervals. In the present embodiment, the plurality of gas ejection portions 30a are provided at portions that are substantially equidistant from the receiving port and the discharge port.
By adopting the arrangement configuration, the mixture of the glass raw material G and the molten glass G flows in the melting tank 11 from the receiving port to the discharge port as a whole (the direction along the arrow X in FIGS. 1, 2 and 3). In addition to the flow in FIG. 3, as shown in FIG. 3, a relatively low temperature glass raw material present below the melting tank 11 along the movement from the bottom to the top of the plurality of bubbles B ejected from the gas ejection holes 30a. A mixture of G and molten glass G convects from the lower side of the melting tank 11 to the upper side. Due to the convection, the mixture of the relatively low temperature glass raw material G and the molten glass G below the melting tank 11 rises to the vicinity of the combustion space S and is heated by the flame K in the combustion space S. Thereby, the whole mixture of the glass raw material G and the molten glass G can be heated more uniformly, and the improvement of thermal efficiency can be aimed at.
Furthermore, in the present embodiment, the air ratio of the premixed gas ejected from the plurality of gas ejection holes 30a is adjusted to the combustible range by the air ratio adjusting unit and ejected. And the temperature is raised to the ignition temperature range inside the mixture of the molten glass G. Thereby, the premixed gas can be self-ignited inside the plurality of bubbles B, and the mixture of the glass raw material G and the molten glass G can be heated from the inside. As a result, the whole mixture of the glass raw material G and the molten glass G can be heated more uniformly, and the thermal efficiency can be improved.

  In the premixed gas flow channels L6 and L7, the premixed gas flow channel L6 is used to prevent backfire from occurring due to the flow of the premixed gas whose air ratio is adjusted to the flammable range. The inner diameter of the premixed gas flow pipe which is L7 is set to be equal to or shorter than the flame extinguishing distance of the fuel gas F. As in this embodiment, when the city gas 13A is used as the fuel gas F and the air ratio is set to 1.1, the pipe inner diameter of the premixed gas flow pipe should be set to 1.7 mm or less. Is preferred.

Incidentally, when producing transparent glass as a product, the operation control unit adjusts the air ratio adjustment unit so that the air ratio of the premixed gas ejected from the plurality of gas ejection holes 30a becomes an oxidizing atmosphere, The flow rate ratio between the oxygen-containing gas A supplied from the flow path 12 and the fuel gas F ejected from the fuel gas ejection section (not shown) of the combustion apparatus N is set so that the combustion space S becomes an oxidizing atmosphere. Adjust the rotational speed of F1.
On the other hand, when producing colored glass as a product, the operation control unit adjusts the air ratio adjustment unit so that the air ratio of the premixed gas ejected from the plurality of gas ejection holes 30a becomes a reducing atmosphere, and gas The flow rate ratio between the oxygen-containing gas A supplied from the flow passage 12 and the fuel gas F ejected from the fuel gas ejection portion (not shown) of the combustion apparatus N is set so that the combustion space S becomes a reducing atmosphere. The number of rotations of the fan F1 is adjusted.
By executing the control, not only the combustion space S in which the flame K is formed, but also the adjustment of the oxidation-reduction atmosphere can be realized from the inside of the object to be melted. For example, the glass raw material G is employed as the object to be melted. In this case, a uniform product with no color unevenness can be produced with the entire glass raw material G.

Now, the inventors of the present application, by earnestly examining, relate to the maximum input heat amount of the premixed gas introduced into the dissolution tank 11 from all of the plurality of gas ejection holes 30a as shown in the graph of FIG. The premixed input heat amount ratio, which is the ratio of the partial input heat amount of the premixed gas introduced from all of the plurality of gas ejection holes 30a to the melting tank 11 with respect to the maximum input heat amount related value to be determined, is determined in advance for each melting furnace. It has been found that when the heat ratio is not more than a specific threshold value determination threshold value (threshold value indicated by a one-dot chain line in FIG. 4), the smaller the air ratio of the premixed gas introduced from the plurality of gas ejection holes 30a, the higher the thermal efficiency.
Incidentally, FIG. 4 is a graph showing the actual test results performed in the test furnace. In the test furnace, as shown in the graph of FIG. 4, the heat amount ratio determination threshold is the premixed input heat amount ratio. That the heat efficiency is higher in the case of the air ratio of 1.5 than in the case of the air ratio of 2.0 when the premixed gas input heat amount ratio is equal to or less than the heat ratio determination threshold. Is obtained.

Therefore, in this embodiment, the plurality of gas ejection holes 30a with respect to the maximum input heat amount related value related to the maximum input heat amount of the premixed gas introduced into the dissolution tank 11 from all of the plurality of gas ejection holes 30a. A premixed input heat amount ratio, which is a ratio of the partial input heat amount of the premixed gas introduced into the melting tank 11 from all, is a specific heat amount ratio determination threshold value determined in advance for each melting furnace (indicated by a one-dot chain line in FIG. 4). Value: In FIG. 4, when the premixed input heat ratio is 60% or less, the operation control unit as the air ratio adjusting unit sets the air ratio of the premixed gas to the lower side.
Thereby, the further improvement of the thermal efficiency of the melting furnace 100 can be aimed at.
Incidentally, the “maximum input heat amount related value related to the maximum input heat amount of the premixed gas introduced into the dissolution tank 11 from all of the plurality of gas ejection holes 30a” is, for example, dissolved from all of the plurality of gas ejection holes 30a This means a heat quantity of about 80% of the maximum input heat quantity of the premixed gas that can be introduced into the tank 11. The maximum input heat amount related value is not limited to about 80%, but is about 80% or more and 100% or less of the maximum input heat amount of the premixed gas that can be introduced into the dissolution tank 11 from all of the plurality of gas ejection holes 30a. It may be a value.
The “specific heat ratio determination threshold” is a threshold determined individually for each melting furnace based on the size of the melting furnace and the like, and is determined by performing a test or the like for each melting furnace 100 in advance. It is stored in a storage unit (not shown).

  The inventors have confirmed that when the premixed gas input heat rate exceeds the heat rate determination threshold, the thermal efficiency tends to increase as the air ratio decreases. That is, in the graph of FIG. 4, when the premixed gas input heat amount ratio exceeds the heat amount ratio determination threshold, the value of the air ratio 2.0 tends to change at a higher thermal efficiency than the graph of the air ratio 1.5. Make sure that there is.

[Another embodiment]
(1) In the above embodiment, an example in which the object to be melted is the glass raw material G is shown. However, the melting object may be a metal other than the glass raw material G.

(2) In the above embodiment, the melting furnace 100 has been described by taking a through-port type melting furnace as an example. However, even if the melting furnace 100 is an under-port type melting furnace or an end-port type melting furnace, the effects of the present invention can be exhibited well.

(3) In the above embodiment, an example is shown in which air is supplied as the oxygen-containing gas A to the combustion device N and the gas ejection hole 30a. Separately, oxygen enriched with oxygen having an oxygen concentration of 21% or more An enriched gas may be supplied.
Moreover, although the example which supplies city gas 13A as fuel gas F was given with respect to the combustion apparatus N and the gas ejection hole 30a, for example, you may supply combustible gas, such as methane gas and natural gas.

(4) In the above-described embodiment, a configuration example in which a plurality of gas ejection portions 30 having one gas ejection hole 30 a is provided has been described. However, a configuration in which a plurality of gas ejection holes 30 a is provided for one gas ejection portion 30 is employed. It doesn't matter.
Even in this configuration, it is preferable to employ a configuration in which the downstream premixed gas passage L7 is connected to each gas ejection hole 30a and the premixed gas is supplied to each gas ejection hole 30a.
Moreover, you may employ | adopt the structure which provides the one gas ejection hole 30a with respect to the one gas ejection part 30. FIG.

(5) In the said embodiment, the some gas ejection hole 30a showed the structural example provided in the bottom part of the dissolution tank 11. As shown in FIG. However, a configuration in which a part of the plurality of gas ejection holes 30 a is provided on the side wall of the dissolution tank 11 may be adopted.

(6) As shown in FIG. 5, the ejection direction (three in FIG. 5) of at least one pair of gas ejection holes 30a among the plurality of gas ejection holes 30a is mutually above the plurality of gas ejection holes 30a. You may employ | adopt the structure provided toward the diffusion direction in which the premixed gas ejected from the gas ejection hole 30a diffuses.
With this configuration, it is possible to promote convection by the bubbles B of the premixed gas in a wider area in a plan view of the dissolution tank 11. Further, in the plan view of the dissolution tank 11, the premixed gas can be ejected to a wider area, and the melting target object can be heated by the combustion of the premixed gas, the entire melting target object can be appropriately heated, and the thermal efficiency is improved. Can be achieved.

(7) As shown in FIG. 6, at least a pair of gas ejection holes 30a (three in FIG. 6) out of the plurality of gas ejection holes 30a are arranged above each other above the plurality of gas ejection holes 30a. You may employ | adopt the structure provided toward the convergence direction where the premixed gas ejected from the gas ejection hole 30a converges.
With this configuration, the bubbles B formed in the object to be dissolved are joined by the premixed gas ejected from at least the pair of gas ejection holes 30a without making the gas ejection speed from the gas ejection holes 30a faster than necessary. The large-sized bubble B can be formed, and convection can be promoted by the large-sized bubble B.

(8) As shown in FIGS. 1 to 3, the plurality of gas ejection holes 30 a are flow directions as a whole from the glass material G receiving port (not shown) to the discharge port (not shown) in the melting tank 11. A configuration example provided at equal intervals in a form that forms a row along a direction (direction along the arrow Z in FIGS. 1, 2, and 3) orthogonal to the direction (direction along the arrow X in FIGS. 1, 2, and 3). Indicated.
However, the plurality of gas ejection holes 30a are formed in, for example, a direction (FIGS. 1, 2, 3) orthogonal to the flow direction of the glass raw material G as a whole (the direction along the arrow X in FIGS. 1, 2, 3) in the melting tank 11. The configuration provided in the form of two or more rows along the direction of the arrow Z) may be adopted. Further, the intervals between the plurality of gas ejection portions 30a may not be equal.

  The configuration disclosed in the above embodiment (including another embodiment, the same shall apply hereinafter) can be applied in combination with the configuration disclosed in the other embodiment, as long as no contradiction occurs. The embodiment disclosed in this specification is an exemplification, and the embodiment of the present invention is not limited to this. The embodiment can be appropriately modified without departing from the object of the present invention.

  The melting furnace of the present invention can be effectively used as a melting furnace capable of melting a melting target object with high thermal efficiency while producing a homogeneous and clear melting product by convection the melting target object in a melting tank. is there.

10: Melting furnace body 11: Melting tank 30a: Gas injection hole 100: Melting furnace A: Oxygen-containing gas F: Fuel gas G: Glass raw material, melting glass L6, L7: Premixed gas flow path N: Combustion device V1: First flow control valve V2: Second flow control valve V3: Third flow control valve

Claims (8)

A gas ejection hole that includes a combustion device that heats a melting target charged in the melting tank with a flame that forms in a combustion space above the melting tank, and jets gas into the melting target that is charged in the melting tank A melting furnace comprising:
A melting furnace comprising a premixed gas introduction mechanism that guides a premixed gas obtained by premixing an oxygen-containing gas and a fuel gas at an air ratio in a combustible range to the gas ejection hole.   The melting furnace according to claim 1, wherein the premixed gas introduction mechanism includes an air ratio adjusting unit that adjusts an air ratio of the premixed gas guided to the gas ejection hole. Introduced from all of the plurality of gas ejection holes to the dissolution tank with respect to the maximum input heat amount related value related to the maximum input heat quantity of the premixed gas introduced into the dissolution tank from all of the plurality of gas ejection holes. When the premixed input heat amount ratio, which is the ratio of the partial input heat amount of the premixed gas, is equal to or less than a specific heat amount ratio determination threshold predetermined for each melting furnace,
The melting furnace according to claim 2, wherein the air ratio adjusting unit sets an air ratio of the premixed gas to a lower side.   The melting furnace according to claim 3, wherein the heat amount ratio determination threshold is a value determined based on the maximum input heat amount related value, and a storage unit that stores the value in advance is provided. A plurality of the gas ejection holes are provided at the bottom of the dissolution tank,
The melting furnace as described in any one of Claims 1-4 provided with the ejection amount adjustment part which can adjust each of the ejection amount of the said premixed gas ejected from the said several gas ejection hole separately for each. A plurality of the gas ejection holes are provided at the bottom of the dissolution tank,
The ejection direction of at least a pair of the gas ejection holes among the plurality of gas ejection holes is in a diffusion direction in which the premixed gas ejected from the gas ejection holes is diffused above the plurality of gas ejection holes. The melting furnace as described in any one of Claims 1-5 provided toward. A plurality of the gas ejection holes are provided at the bottom of the dissolution tank,
The ejection direction of at least one pair of the gas ejection holes among the plurality of gas ejection holes is in a convergence direction in which the premixed gas ejected from the gas ejection holes converges above the plurality of gas ejection holes. The melting furnace as described in any one of Claims 1-5 provided toward. The premixed gas introduction mechanism includes a premixed gas flow pipe that flows through the premixed gas and is connected to the gas ejection hole,
The melting furnace according to any one of claims 1 to 7, wherein a pipe inner diameter of the premixed gas flow pipe is equal to or less than a flame extinguishing distance of the fuel gas.

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