JP2004238236A - Glass melting method and glass melting equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a glass melting method and equipment wherein useful components contained in the waste gas generated during glass melting are recovered to reutilize them as raw glass materials. <P>SOLUTION: A raw glass material 2 is heated by using a substantially sulfur-free fuel 3 as a fuel for a burner flame which heats the raw glass material 2 in glass melting to obtain molten glass. Gaseous useful components and particulate useful components contained in the waste gas 4 discharged from a glass melting furnace 1 are collected by contact with water to obtain a collected liquid 9. The collected liquid 9 is neutralized to obtain a neutralized collected liquid 13. The liquid 13 is subjected to solid/liquid separation by means of a spray drier 21 to obtain a raw recycle material 22, and the material 22 is reutilized as the raw glass material 2. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a glass melting method and a glass for collecting gaseous useful components and particulate useful components contained in an exhaust gas discharged from a glass melting furnace, and recovering the useful components in a state where the useful components can be used as glass raw materials. Related to melting equipment.
[0002]
[Prior art]
In a glass product manufacturing process, a powdery or granular glass raw material is supplied to a glass melting furnace, heated by a burner flame to obtain molten glass, and the product is obtained by a molding method such as pressing or blowing. When heating and melting glass raw materials, gaseous substances such as sulfur oxides and nitrogen oxides are generated as combustion waste gas from sulfur compounds and nitrogen compounds contained in the glass raw materials, and constitute a part of the glass composition. Boron compounds and arsenic compounds are also vaporized substances. Most of these vaporized substances are present in a gaseous state in the exhaust gas, but a part of them is condensed to form a mist (or fume) and float in the exhaust gas.
[0003]
In the glass melting furnace, the glass material is heated and melted by a burner flame which burns a liquid fuel such as heavy oil or kerosene or a gaseous fuel such as LPG. At this time, a part of the powdery or granular glass material is partially melted. It mixes with the exhaust gas together with the combustion waste gas of the burner flame. Further, the exhaust gas contains sulfur oxides and nitrogen oxides generated by the combustion of liquid fuel or gaseous fuel. It is known that some of the vaporized substances from the glass raw materials, some of the glass raw materials, and the combustion waste gas present in the exhaust gas include those that have a bad effect on the environment if released directly into the atmosphere. ing. The substances that affect the environment include sulfur oxides, nitrogen oxides, arsenic, arsenic compounds, boron, boron compounds, chlorine, chlorine compounds, etc. (hereinafter referred to as exhaust gas emissions), depending on the glass composition.
[0004]
As an exhaust gas purifying apparatus, for example, Patent Document 1 discloses an apparatus for purifying exhaust gas generated from a boiler in a desulfurization apparatus. In the case of this apparatus, after exhaust gas is purified, boron, heavy metal, etc. Toxic substances and gypsum are formed. In the case of glass melting, the harmful substances mentioned above include the emission of exhaust gas, and the collected liquid is oxidized using sodium hypochlorite and coagulated using ferric chloride. After that, it is filtered and treated as specially managed industrial waste.
[0005]
[Patent Document 1]
JP 2001-179047 A (Page 1-12, FIG. 1)
[0006]
[Problems to be solved by the invention]
As mentioned above, harmful substances after exhaust gas purification treatment are treated as specially controlled industrial waste, but in recent years it has been difficult to secure industrial waste disposal sites, and in particular, it is extremely difficult to dispose of specially controlled industrial waste. And the cost of processing is soaring, there is a problem in terms of cost and environmental pollution when the waste from the glass melting furnace is disposed of.
[0007]
In addition, the emission of the exhaust gas from the glass melting furnace is a vaporized substance from the glass raw material, a part of the glass raw material and a combustion waste gas, and contains components constituting a part of the glass composition. . Above all, arsenic and arsenic compounds have a large fining effect to improve bubble elimination during glass melting, boron and boric acid compounds are important constituents of glass composition, and chlorine and chlorine compounds reduce the viscosity of glass to reduce glass melting. All are useful substances for glass, for example, for ease of use. Further, the combustion waste gas contains sulfur oxides and nitrogen oxides, which are also components contained in trace amounts in glass. As described above, the exhaust gas contains many components that can be used as a glass material, and disposal of the exhaust gas leads to depletion of global resources.
[0008]
However, since the exhaust gas emission contains a large amount of sulfur compounds in the combustion waste gas derived from the fuel, if these are used as a glass raw material, they cause bubbles when the glass is melted. Was not used. Also, as described above, chlorine compounds are used for purification of harmful substances in exhaust gas, so the chlorine concentration contained in exhaust gas after purification becomes excessively high for use as glass material. Until then, it was not used as a raw material for glass. In addition, there is a problem in that the residue after the exhaust gas exhaust gas is purified contains moisture, which causes solidification when mixed with other glass materials.
[0009]
SUMMARY OF THE INVENTION An object of the present invention is to provide a glass melting method and a glass melting facility that recover useful components contained in an exhaust gas and can reuse them as glass raw materials without containing excessive chlorine compounds.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the glass melting method of the present invention is a glass melting method in which a glass raw material is heated by a burner flame in a glass melting furnace to obtain a molten glass, while substantially serving as a fuel for the burner flame. Heating a glass raw material using a sulfur-free fuel to obtain a molten glass, while bringing gaseous and particulate useful components contained in exhaust gas discharged from a glass melting furnace into contact with water; To collect the collected liquid, neutralize the collected liquid to obtain a neutralized collected liquid, and then separate the neutralized collected liquid into solid and liquid to collect useful components that can be used as glass raw materials It is characterized by doing.
[0011]
In the melting of glass, if the amount of sulfur oxide mixed into the glass raw material increases, a large amount of air bubbles are generated during the melting of the glass, and these air bubbles remain in the glass to cause defective bubbles and impair the quality of the glass product. In recent years, since higher quality is required for glass products, reduction of the amount of sulfur oxide mixed into glass raw materials which causes bubbles to remain is required.
[0012]
In the present invention, a fuel containing substantially no sulfur content is used as a burner flame fuel for heating a glass raw material in a glass melting furnace. Therefore, the generation of sulfur oxides in the exhaust gas emission is included in the glass raw material. Substantially limited to sulfur oxides generated from sulfur compounds. It is generally appropriate to use a gaseous fuel having a low sulfur compound content as the fuel for the burner flame, but the sulfur content is 0.001% by mass or less in order to substantially contain no sulfur content. Is preferred. On the other hand, with respect to the sulfur compound contained in the glass raw material, the cause of remaining bubbles can be avoided by using a raw material having a low sulfur content. As the fuel containing no sulfur used in the present invention, LPG (liquefied petroleum gas), LNG (liquefied natural gas) and the like can be used. In general, LNG has a lower sulfur oxide content, but if the sulfur content is less than 0.001% by mass, LPG, which generates a larger amount of heat per unit mass, obtains the same calorific value as combustion waste. This is preferable in that the amount of generated gas can be reduced. Further, it is important from the viewpoint of preventing scattering of useful components that the gaseous useful components and particulate useful components contained in the exhaust gas are brought into solution to be collected by contacting the exhaust gas with water.
[0013]
Since the collected liquid of the exhaust gas exhaust gas composed of gaseous substances and minute solid substances in the exhaust gas is generally acidic, in the present invention, the collected liquid is prepared by adding an alkali component to the collected liquid, I do.
[0014]
The collected liquid is neutralized by adding an alkali component so that the hydrogen ion concentration (PH) becomes weakly alkaline, which is 6.8 to 7.8, and more preferably 7 to 7.5.
[0015]
If the pH of the collected liquid is less than 6.8, it is likely to cause corrosion of piping and the like, and if the pH exceeds 7.8, the calcium component and boric acid added for the neutralization treatment will be lost. The bond forms insoluble calcium borate, which causes scale clogging on the inner surface of the pipe, causing clogging of the pipe.
[0016]
Alkaline earth metal compounds, especially calcium compounds such as slaked lime and quicklime, are generally used as alkali components to be added to neutralize the collected liquid. An alkali metal compound such as caustic soda and caustic potash can be used as long as the composition does not make the alkali metal compound a problem.
[0017]
Further, it is important to neutralize the collected liquid with slaked lime or the like to obtain a neutralized collected liquid in order to extend the life of the equipment.
[0018]
The neutralized collected liquid is separated from water to recover a solid content, and a solid-liquid separation method is generally filtration. However, in the case of filtration, there is a problem that water remains in the filter cake, and if the filter cake containing water is directly added to the glass raw material, the water hardens the glass raw material and hinders smooth charging into the glass melting furnace. It is necessary to dry the cake before adding it to the glass raw material. In the present invention, the solid-liquid separation step is simplified by employing a method of evaporating and drying the neutralized collected liquid using a drum dryer or, more preferably, a spray dryer, and directly collecting the solid content.
[0019]
Further, the glass melting method of the present invention is characterized in that the useful component contained in the exhaust gas is at least one of arsenic, an arsenic compound, boron, a boron compound, chlorine or a chlorine compound.
[0020]
As useful components contained in the exhaust gas that can be used as a glass raw material, arsenic, arsenic compounds, boron, boron compounds, chlorine or chlorine compounds are useful components that have a problem in air release and can be reused. The present invention makes it possible to collect such useful components contained in exhaust gas in gaseous form and particulate form.
[0021]
Further, the glass melting equipment of the present invention, in a glass melting furnace that obtains molten glass by heating a glass raw material by a burner flame inside, and a glass melting equipment equipped with a treatment device for exhaust gas discharged from the glass melting furnace, Is a spray tower that collects gaseous useful components and particulate useful components contained in the exhaust gas by contacting with water to form a first collected liquid, Wet dust collector that collects useful components and uses it as a second collection liquid, and a neutralization tank that neutralizes the first collection liquid and the second collection liquid to obtain a neutralization collection liquid And a solid-liquid separation means for collecting a useful component usable as a glass material by solid-liquid separation of the neutralized collected liquid.
[0022]
In the facility of the present invention, as a method of washing exhaust gas with water, a spray tower, a jet scrubber, a bubble tower, and the like are possible, and a spray tower is not required to apply a high pressure, and there is no fear of clogging. It is suitable. Further, as the wet type electrostatic precipitator, a flat type, a tube type, a cylindrical type, and the like are possible, and a flat type is preferable in that there is no fear of clogging. As the solid-liquid separation means, a spray dryer, a drum dryer, or other solid-liquid separation means by evaporation can be used.In the case of this method using exhaust gas as a heat source, there is no fear of clogging. Spray dryers are preferred.
[0023]
In the present invention, water is sprayed on soluble gaseous substances contained in the exhaust gas generated from the glass melting furnace and collected by dissolving in water droplets to collect a liquid, and water is added to the fine solid substance. Spray and collide with water droplets to collect in the water droplets and collect as a collected liquid.
[0024]
First, by lowering the exhaust gas introduced into the spray tower to 65 ° C. or less by sensible heat and latent heat of water, gaseous arsenic, arsenic compounds, boron and boron compounds are crystallized at high temperatures into solid particles, Water droplets scattered on the fine solid substance introduced together with the solid particles and the exhaust gas are collided and collected in the water droplets to be collected as a collected liquid. Also, soluble gaseous substances such as chlorine and hydrogen chloride in the exhaust gas can be dissolved in the sprayed water droplets, collected and collected as a collected liquid.
[0025]
It is difficult to collect all gaseous substances and fine solid substances in the exhaust gas using the spray tower alone. Particularly, solid particles crystallized from the exhaust gas cooled in the spray tower may pass through without being collected in the spray tower due to the small particle diameter. In the present invention, the exhaust gas that has passed through the spray tower is further introduced into a wet electrostatic precipitator, and fine solid substances in the exhaust gas that could not be collected by the spray tower are collected. In a wet electric precipitator, the collected matter electrically attached to the collecting plate is washed with water and collected as a collected liquid.
[0026]
In the present invention, gaseous substances and fine solid substances in exhaust gas are collected by a spray tower and a wet type electrostatic precipitator having a simple structure, so that enormous equipment costs are not required and maintenance is not required.
[0027]
Furthermore, the glass melting equipment of the present invention is characterized by comprising a spray dryer as solid-liquid separation means.
[0028]
In the present invention, a spray dryer is provided between a glass melting furnace and a spray tower, a neutralization collecting liquid is supplied from a neutralization tank to the spray dryer, and the neutralization collecting liquid is dehydrated by heat of exhaust gas from the glass melting furnace. A method of collecting a solid content by drying is adopted. The spray dryer includes a rotary atomizer disk system and a universal pressure nozzle system, both of which can be used.Sharpness is not required for the particle size distribution of the dehydrated and dried solids, while the universal pressure system is compact and can be processed in large quantities. The nozzle method is suitable.
[0029]
Part of the fine powder solids obtained by dehydrating and drying the neutralized collected liquid with a spray dryer becomes dust, but by installing a spray dryer in the previous step of the spray tower, the dust generated by the spray dryer can collect useful components. It can be collected by the spray tower of the collector and the wet electric dust collector.
[0030]
Further, as described above, in the present invention, in recovering useful components contained in the exhaust gas, since chlorine compounds that have been conventionally used are not used, the exhaust gas effluent that has conventionally been disposed of is used as a glass raw material. It can be used.
[0031]
In the glass melting method of the present invention, useful components contained in the exhaust gas and reusable as glass raw materials include arsenic, arsenic compounds, boron, and boron, which are constituents of glass and easily become vaporized substances during glass melting. It is one or more of compounds, chlorine, and chlorine compounds, and may further contain components constituting a glass composition discharged as a vaporized substance when the glass is melted.
[0032]
BEST MODE FOR CARRYING OUT THE INVENTION
One embodiment of a glass melting facility according to the present invention will be described with reference to FIG.
[0033]
As shown in FIG. 1, a glass melting facility heats a glass raw material 2 prepared to have a target glass composition in a glass melting furnace 1 with a burner flame generated by combustion of a fuel 3. As the fuel 3, LPG having a sulfur content of 0.001% by mass or less is used to substantially eliminate the generation of sulfur oxides due to combustion.
[0034]
In the exhaust gas 4 generated from the glass melting furnace 1, in addition to the combustion waste gas of the fuel 3, gaseous substances and fumes of glass components, and fine solid substances such as glass raw materials wound up by a burner flame during combustion of the fuel 3. It is contained. The exhaust gas 4 is introduced into a spray tower 5 provided in a useful component collector 7 composed of a spray tower 5 and a wet electric precipitator 6. Wash water 8 is sprayed in the spray tower 5, and the exhaust gas 4 comes into contact with the sprayed wash water 8, so that most of the fine solids and vaporized substances in the exhaust gas 4 crystallized by cooling are washed water 8. The soluble vaporized substances in the exhaust gas 4 that are not collected and crystallized are also dissolved in the sprinkled washing water 8 to form a collected liquid 9.
[0035]
However, since there are minute solid substances that pass through the spray tower 5 without contacting the washing water 8 in the spray tower 5, the exhaust gas that has passed through the spray tower 5 is introduced into a wet-type electrostatic precipitator 6 provided in the next step. Fine solid substances not collected by the spray tower 5 are collected. The fine solid substance collected by the wet electric precipitator 6 is washed away by the washing water 8 to become a collected liquid 9, and is introduced into the neutralization tank 10 together with the collected liquid 9 generated in the spray tower 5. The exhaust gas 4 after being cleaned after passing through the wet electrostatic precipitator 6 is discharged from the chimney 11 into the atmosphere.
[0036]
The collected liquid 9 introduced into the neutralization tank 10 is neutralized by adding slaked lime 12 and introduced into a drum dryer 14 as a neutralized collected liquid 13, and is evaporated by evaporation under heating 16 to solid-liquid separation. It is supposed to be. The separated solid content is reused as a raw material 15 for the glass material, and the evaporated portion 16 is recovered as water by a condensation recovery device 17 and reused in addition to the washing water 8.
[0037]
Next, an embodiment of the glass melting method according to the present invention using the above glass melting equipment will be described with reference to FIG. The same parts as those in FIG. 1 are denoted by the same reference numerals.
[0038]
In a glass melting furnace 1, a glass raw material 2 prepared to have a target glass composition is heated by a burner flame generated by burning a fuel 3. As the fuel 3, LPG having a sulfur content of 0.001% by mass or less is used to substantially eliminate the generation of sulfur oxides due to the combustion of the fuel.
[0039]
In the exhaust gas 4 generated from the glass melting furnace 1, in addition to the combustion waste gas of the fuel 3, vaporized substances of glass constituents, fumes, and fine solid substances such as glass raw material powder rolled up by a burner flame at the time of burning the fuel 4. Is contained. The exhaust gas 4 is introduced into the spray dryer 21 and used as a heat-drying heat source for the spray dryer 21. The exhaust gas that has passed through the spray dryer 21 is introduced into the useful component collecting device 7 including the spray tower 5 and the wet electric dust collector 6 together with the fine powder solids generated by the spray dryer. In the spray tower 5, water supplied as washing water 8 is sprinkled, and fine solid substances in the introduced exhaust gas, fine powder solids generated in the spray dryer 21, and exhaust gas crystallized by cooling with the sprayed water. The vapors inside are collected by colliding with the sprinkled water. In addition, the soluble vaporized substance that has not been crystallized is also dissolved in the sprinkled water and collected to form a collection liquid 9. The fine solid matter that has not been collected in the spray tower 5 is introduced into the wet electric precipitator 6 and collected by the collecting plate, washed off with the washing water 8 to become the collected liquid 9, and the collected liquid generated in the spray tower 5 And is introduced into the neutralization tank 10. The clean exhaust gas that has passed through the wet electrostatic precipitator 6 is discharged from the chimney 11 into the atmosphere.
[0040]
The collected liquid 9 introduced into the neutralization tank 10 is neutralized by adding slaked lime 12 and introduced into a spray drier 21 as a neutralized collected liquid 13. . The solid matter separated into solid and liquid is reused as a glass raw material as a recycled raw material 22, while the uncollected fine solid substance and vaporized steam are recirculated to the useful component collecting device together with the exhaust gas.
[0041]
【The invention's effect】
As described above, according to the glass melting method of the present invention, by using a fuel that does not substantially contain sulfur as a fuel for a burner flame that heats a glass raw material in a glass melting furnace, the exhaust gas emission is reduced. The generation of sulfur oxides can be substantially limited to sulfur oxides originating from sulfur compounds contained in the glass raw material. The useful component in the exhaust gas accompanying the above can be collected and reused as a useful component of the glass raw material, and the load on the environment can be significantly reduced.
[0042]
According to the glass melting equipment of the present invention, gaseous substances and fine solid substances in exhaust gas are collected by a spray tower having a simple structure and a wet-type electrostatic precipitator, so that enormous equipment costs are required. In addition, since there is no need for maintenance work, the glass melting method of the present invention can be efficiently implemented with low equipment costs and operating costs.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing an embodiment of a glass melting method according to the present invention.
FIG. 2 is an explanatory view showing an embodiment provided with a spray dryer in the glass melting method according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Glass melting furnace 2 Glass raw material 3 Fuel 4 Exhaust gas 5 Spray tower 6 Wet electric precipitator 7 Useful component collection device 8 Washing water 9 Collection liquid 10 Neutralization tank 11 Chimney 12 Slaked lime 13 Neutralization collection liquid 14 Drum dryer 15, 22 Recycled raw materials 16 Evaporation 17 Condensation recovery unit 21 Spray dryer

Claims (4)

In a glass melting method of heating a glass raw material by a burner flame in a glass melting furnace to obtain a molten glass,
On the one hand, a glass raw material is heated by using a fuel substantially free of sulfur as a fuel of the burner flame to obtain a molten glass, and on the other hand, a gaseous useful component contained in an exhaust gas discharged from a glass melting furnace. And collecting the particulate useful component by contacting it with water to form a collecting liquid, neutralizing the collecting liquid to form a neutralized collecting liquid, and then separating the neutralized collecting liquid into a solid and a liquid. Thereby recovering a useful component usable as a glass raw material. The glass melting method according to claim 1, wherein the useful component contained in the exhaust gas is one or more of arsenic, an arsenic compound, boron, a boron compound, chlorine, and a chlorine compound. In a glass melting furnace which obtains a molten glass by heating a glass raw material by a burner flame therein, and a glass melting facility equipped with a treatment device for exhaust gas discharged from the glass melting furnace,
The exhaust gas treatment device is a spray tower that is collected by contacting gaseous useful components and particulate useful components contained in the exhaust gas with water to be a first collected liquid, and passes through the spray tower. A wet electrostatic precipitator that collects particulate useful components from exhaust gas and uses it as a second collection liquid; and a neutralized collection liquid that neutralizes the first collection liquid and the second collection liquid. And a solid-liquid separation means for collecting a useful component usable as a glass material by subjecting the neutralized collected liquid to solid-liquid separation. The glass melting equipment according to claim 3, wherein the solid-liquid separation means includes a spray dryer.

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