JP2813543B2 - Waste gas treatment equipment for glass synthesis equipment for optical fibers - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waste gas treatment apparatus for a glass synthesizing facility for optical fibers, and more particularly to a waste gas treatment apparatus using a pre-coated bag filter.

[0002]

2. Description of the Related Art Since waste gases of glass fiber synthesizing equipment for optical fibers contain harmful substances such as HCl and Cl ₂ , glass synthesizing equipment for optical fibers removes harmful substances from the waste gas. A device is provided.

Recently, it has been studied to incorporate a pre-coated bag filter into this waste gas treatment apparatus. Pre-coated bag filters are conventionally used in waste gas treatment equipment in garbage incinerators. By adding a pre-coating agent to the waste gas introduced into ordinary bag filters, dust collection efficiency and removal of harmful substances are reduced. While increasing the rate,
This improves the ability to remove dust ash from the filter cloth.

[0004]

The conventional pre-coated bag filter generally uses a system in which a constant amount of a pre-coating agent is constantly added to waste gas. However, when synthesizing glass for an optical fiber, since the components of the raw material gas are different at the beginning and the end of the synthesis process, the concentration of harmful substances contained in the waste gas changes. Further, since the waste gas treatment device is generally a method of collecting and treating waste gas from a plurality of synthesis facilities, in such a method, the concentration of harmful substances in the waste gas introduced into the waste gas treatment device is further increased. It changes greatly.

[0005] As described above, a conventional precoat-type bag filter (in which a constant amount of a precoat agent is constantly added) is applied to a waste gas treatment apparatus in which the concentration of harmful substances to be removed changes.
The following problem arises when is applied. That is, if the amount of the precoat agent added is too small relative to the concentration of harmful substances in the waste gas, the harmful substance removal rate in the bag filter decreases, and the load on the waste gas treatment unit in the subsequent process increases, or the exhaust gas The concentration of harmful substances in them may exceed the standard. If the amount of the precoat agent added is too large relative to the concentration of harmful substances in the waste gas, the amount of the precoat agent used and the amount of dust collection ash discharged will increase, leading to an increase in running costs and industrial waste.

[0006]

SUMMARY OF THE INVENTION The present invention provides a waste gas treatment apparatus for an optical fiber glass synthesizing facility which has solved the above problems. In a waste gas treatment apparatus including a pre-coated bag filter for treating waste gas in equipment, a concentration detecting means for detecting a harmful substance concentration in waste gas is provided at an inlet of the pre-coated bag filter, and the concentration detecting means is provided. And a control means for automatically controlling the amount of the pre-coating agent added to the pre-coating type bag filter in accordance with the concentration of the harmful substance detected in (1).

A second aspect of the present invention relates to a waste gas treatment apparatus including a pre-coated bag filter for treating waste gas in a glass synthesis facility for optical fibers, wherein the amount of raw material gas supplied to the glass synthesis facility for optical fibers is reduced. The present invention is characterized in that arithmetic means for calculating the amount of the precoat agent added to the precoat type bag filter is provided, and control means for automatically controlling the amount of the precoat agent added according to the output of the arithmetic means is provided.

[0008]

According to the first aspect of the present invention, when the concentration of harmful substances in the waste gas introduced into the precoat type bag filter is high, the amount of the precoat agent is large, and when the concentration of harmful substances is low, the amount of the precoat agent is small. Control is performed so as to reduce the number. This ensures the necessary waste gas treatment efficiency by using the minimum necessary pre-coating agent.

Further, the concentration of harmful substances in the waste gas has a certain correlation with the amount of raw material gas used in the glass fiber synthesizing facility for optical fibers. The concentration of the harmful substance in the waste gas (that is, the amount of the precoat agent added) is obtained from the amount, and the same control as in the first aspect is performed.

As a result, the overload of the waste gas treatment unit in the post-process of the pre-coated bag filter, the harmful substance concentration in the exhaust gas exceeds the standard, the excessive use of the pre-coating agent,
Excessive discharge of dust ash can be suppressed.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an embodiment of the present invention. In this apparatus, waste gas discharged from an optical fiber glass synthesizing facility 11 is first treated by a precoat type bag filter 13 and then treated by a waste gas treatment unit 15 such as a packed tower scrubber. Waste gas from which harmful substances have been removed is fan 17
Is released into the atmosphere.

The pre-coated bag filter 13 converts the waste gas discharged from the optical fiber glass synthesizing facility 11 into, for example, Ca (O
H) Pre-coating agent supply device 19 for adding a pre-coating agent such as ₂ , zeolite or CaCO _3, and a bug that removes harmful substances together with the pre-coating agent from waste gas to which the pre-coating agent has been added by the pre-coating agent supply device 19. And a filter 21.

The precoating agent supply device 19 comprises a hopper 23 storing the precoating agent, and a screw feeder 25 for supplying the precoating agent from the hopper 23 to the waste gas. The amount of the precoat agent added to the waste gas can be adjusted by changing the rotation speed of the motor 27 of the screw feeder 25. The bag filter 21 filters waste gas containing a precoat agent with a filter cloth 29 to separate harmful substances from the waste gas together with the precoat agent. Numeral 31 denotes dust collected from the bag filter 21.

Since the harmful substances cannot be sufficiently removed only by the pre-coated bag filter 13, the waste gas passing through the pre-coated bag filter 13 is further processed by the waste gas processing unit 15 in the next step.

The waste gas treatment apparatus using the precoat type bag filter 13 has the above configuration. This device further comprises a concentration detector 33 for detecting the concentration of harmful substances in the waste gas at the entrance of the pre-coat type bag filter 13,
A converter 35 for obtaining the amount of the precoat agent added from the concentration detected by the concentration detector 33, and a speed control device 37 for controlling the rotation speed of the motor 27 of the screw feeder 25 by the output of the converter 35 are provided. is there.

In the converter 35, the relationship between the concentration of harmful substances in the waste gas and the appropriate amount of the precoat agent added is set in advance. Therefore, when the concentration of the harmful substance is input from the concentration detector 33, the converter 35 outputs an appropriate amount of the precoat agent added according to the concentration as an electric signal. Speed control device
37 controls the rotation speed of the motor 27 of the screw type feeder 25 according to the signal. As a result, an appropriate amount of the precoat agent according to the concentration of the harmful substance at that time is added. Therefore, the precoat agent can always be added without excess or deficiency.

FIG. 2 shows a second embodiment of the present invention. 2, the same parts as those in FIG. 1 are denoted by the same reference numerals. The waste gas treatment apparatus is the same as that of the above-described embodiment in that the waste gas treatment apparatus is configured by a combination of the precoat type bag filter 13 and another waste gas treatment unit 15. Waste gas treatment equipment is usually
The system is configured to collect and treat waste gas from a plurality of optical fiber glass synthesizing facilities 11. Each synthesis facility 11 is supplied with a raw material gas for glass synthesis from a source gas supply device 39, and the supply amount is controlled by a mass flow controller (mass flow controller) 41 for each synthesis facility 11.

There is a correlation between the supply amount of the raw material gas and the concentration of harmful substances in the waste gas. For example, the raw material gas (SiC
Experiments and results show that supplying 170 g / min of l ₄ ) releases 142 g / min of HCl. In addition, SiCl ₄ reacts and becomes SiCl ₄ + 2H ₂ + O ₂ → SiO ₂ + 4HCl, but actually, a part of SiCl ₄ becomes SiCl ₄ + O ₂ → SiO ₂ + 2Cl ₂ . HCl in the waste gas: Cl ₂ is 30 to 35 in a molar ratio according to the results: 1.

Therefore, if the supply amount of the source gas is known,
The concentration of harmful substances in waste gas can be estimated. Therefore, in this apparatus, the supply amounts of the raw material gas are read from the mass flow controller 41 of each synthesis facility 11, and the totals are read to obtain the concentrations of HCl and Cl ₂ in the waste gas supplied to the precoat type bag filter 13, Further, an arithmetic unit 43 for obtaining an appropriate amount of the precoat agent added thereto is provided. By inputting the output of the arithmetic unit 43 to the speed control device 37 and controlling the rotation speed of the motor 27 of the screw type feeder 25, it is possible to add an appropriate amount of the precoat agent according to the concentration of the harmful substance.

In the above embodiment, the screw type feeder was used to supply the pre-coating agent. However, the pre-coating agent supply means is not limited to this. For example, a table type feeder, a rotary valve or the like may be used. it can.

[0021]

According to the present invention described above, according to the present invention, when using a precoat type bag filter, to process the waste gas of harmful substances concentration greater change optical fiber glass synthesis equipment, precoat type bug since such adding an appropriate amount of precoat agent according to hazardous substance concentration <br/> waste gas introduced into the filter, it can be removed at a reliably predetermined efficiency hazardous substances. Further, since the amount of the pre-coating agent used and the amount of dust collection ash discharged can be minimized, it is extremely effective in reducing the running cost and the amount of industrial waste.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an embodiment of the invention of claim 1;

FIG. 2 is an explanatory view showing an embodiment of the invention of claim 2;

[Explanation of symbols]

11: Glass synthesis equipment for optical fiber 13: Pre-coat type bag filter 15: Waste gas treatment unit for the next process 19: Pre-coating agent supply device 17: Fan 21: Bag filter 23: Hopper 25: Screw feeder 27: Motor 29: Filter Cloth 31: Dust ash 33: Detecting concentration of harmful substances in waste gas 35: Converter 37: Rotation speed control device 39: Raw material gas supply device 41: Mass flow controller 43: Computing unit

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-123515 (JP, A) JP-A-2-298316 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B01D 46/02 B01D 46/42

Claims (3)

(57) [Claims] In a waste gas treatment apparatus including a pre-coated bag filter for treating waste gas in an optical fiber glass synthesizing facility, a concentration for detecting a harmful substance concentration in the waste gas at an inlet of the pre-coated bag filter. A glass synthesizing facility for an optical fiber, comprising a detecting means and a control means for automatically controlling the amount of a precoating agent added to a precoated bag filter according to the concentration of a harmful substance detected by the concentration detecting means. Waste gas treatment equipment. 2. A waste gas treatment apparatus including a pre-coat type bag filter for treating waste gas of an optical fiber glass synthesis facility, wherein a pre-coating of the pre-coat type bag filter is performed based on a supply amount of raw material gas of the optical fiber glass synthesis facility. A waste gas treatment system for a glass synthesizing facility for optical fibers, comprising: a calculating means for calculating the addition amount of the chemical agent; and a control means for automatically controlling the addition amount of the precoat agent according to the output of the calculating means. apparatus. 3. The method according to claim 1, wherein the calculating means calculates the addition amount of the precoating agent by summing the outputs of a plurality of mass flow controllers of the raw material gas provided in the glass synthesizing equipment for optical fiber. The waste gas treatment device according to claim 2.