JPH06168B2 - Combustion furnace exhaust gas dust removal method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a method and apparatus for removing fine particles contained in high temperature exhaust gas of a combustion furnace.

<Prior Art> Conventionally, in a combustion furnace, a considerable amount of soot dust is discharged together with high temperature combustion gas, which is one of the causes of air pollution.
As the flue gas treatment, for example, a dust removing means using a cyclone or a cotrel is known, but these have a particle size of 10 μm.
Particles smaller than a certain degree are difficult to remove, and if they are expensive or if there is soot of incomplete combustion, the electric resistance value becomes remarkably small, and soot is scattered with the gas flow. In addition, the means using a bag filter has drawbacks such as clogging of the filter fabric, it is difficult to collect homogeneous soot and dust, the fabric is generally weak to moisture, and fatigue fracture may occur.

<Problems to be Solved by the Invention> The present invention provides a method and apparatus for removing dust and the like contained in high temperature exhaust gas from a combustion furnace, which solves the drawbacks of the prior art. It is extremely easy to use to remove fine particles such as soot and dust contained in the high temperature exhaust gas from the combustion furnace, in particular, even submicron particles to obtain clean exhaust gas.

<Means for Solving the Problems> The present invention uses the combustion furnace high temperature exhaust gas as an aqueous medium to cool to a temperature lower than the deformation temperature of the communicating porous resin material used as a dustproof filter, and then cools the generated cooling. Exhaust gas containing water droplets containing fine dust is coated on the inlet side with a fluorine- or silicon-containing continuous porous resin material having a thickness of 5 μm to 100 μm and a contact angle of 100 ° or more with water droplets having a pore diameter of 1 μm to 10 μm. , Thickness 1mm to 20mm, hole diameter 2
A method and apparatus for removing combustion exhaust gas by passing through a dust collecting filter made of a porous resin material having a diameter of 0 μm to 60 μm and applying backwashing air to the dust collecting filter.

The present invention will now be described with reference to FIG. Combustion high-temperature exhaust gas, which is usually 800 ° C. to 1000 ° C., generated in the combustion furnace A is sent to the cooling means B via the flue 1. Cooling means B
Is, for example, a spray 3 using the cooling aqueous medium 2 to a temperature lower than the deformation temperature of the communicating porous resin material of the dust removing filter 5 used in the subsequent dust removing means C (100 ° C. or less in some cases). Is cooled in the cooling section using, and preferably quenched. The exhaust gas cooled here and the aqueous medium 2 that has cooled the exhaust gas are sent to the dust removing means C via the flue 4 as exhaust gas containing a part of water droplets containing fine soot dust. The dust removing means C is a dust collecting filter 5 made of a porous resin material 7 in which the cooled exhaust gas is coated with a continuous porous resin material 6 containing fluorine or silicon having a contact angle of 100 ° or more with water droplets on the inlet side. It is composed of a single or a plurality of dust collecting filters provided so as to pass through the inside. Exhaust gas that has passed through the dust collecting filter 5 to be removed of dust and becomes clean is discharged from the chimney D into the atmosphere through the flue 8. The soot dust captured by the dust collecting filter 5 and a part of the aqueous medium are discharged from the outlet 10.

Next, the dust collecting filter 5 that has captured the entrained water droplets together with the soot dust in the cooling exhaust gas is dedusted by backwashing the air from the air supply pipe 9, and the remaining soot dust and the entrained water droplets are further discharged from the outlet 10. Depending on the case, if the dust collecting filters of the plurality of dust collecting filters 5 that have finished collecting dust are sequentially backwashed with air, entrained water droplets can be continuously taken out simultaneously with soot and dust.
It can also be discharged more.

Next, FIG. 2 shows another example B'of the cooling means B shown in FIG. In FIG. 2, an attracting fan 11 is provided following the spray 3 as in FIG. By using the induction fan 11, the flue gas 1 can be sucked and at the same time the exhaust gas 4 can be smoothly sent to the dust removing means C.

FIG. 3 shows another example B ″ which is a modification of the cooling means B of FIG. 1. The cooling means B ″ uses a cooling aqueous medium 2 to spray 3, wet wall film 12, and filler 13 such as Raschig rings. Is used to cool the exhaust gas 1, preferably to quench it. The aqueous medium 2 in which the exhaust gas is cooled is the pump 14, the heat exchanger 1
It can be circulated and used for cooling the high-temperature exhaust gas via Step 5.

In the drawings, an example in which a spray, a wetting wall, and a filler are used at the same time is shown, but any one of these alone or any two, such as a spray and a wetting wall, a spray and a filler, and the like, may be combined in any desired manner. It can also be used as

The combustion furnace high-temperature exhaust gas in the present invention includes, for example, boilers used for petroleum, coal, etc., plastics, radioactive materials, industrial waste, incinerators for garbage, etc., and other various combustion furnaces, and includes particles such as dust. The high-temperature combustion exhaust gas can be used as it is, or the high-temperature combustion exhaust gas generated through a desulfurization step, and optionally a denitration step, can be used.

Next, as the aqueous medium that can be used in the present invention, in addition to water, N
It may be an aqueous salt solution such as aCl, Na ₂ SO ₄ , or Na ₂ SO ₃ , or may be NaOH or Na ₂ C as the case may be.
It may be an alkali such as O ₃ , NaHCO ₃ , NH ₄ OH, Ca (OH) ₂ or the like, and optionally an acid aqueous solution such as HCl or H ₂ SO ₄ . In particular, combustion furnace high temperature exhaust gas is SO ₂ , H
_In the case of an acidic gas containing ₂ S and the like, it is preferable to use an alkaline aqueous solution.

In the present invention, the combustion furnace high-temperature exhaust gas usually has a high temperature of about 800 to 1000 ° C., but the temperature is lower than the deformation temperature of the continuous porous resin material used in the next use of this exhaust gas, and in some cases 100 ° C. It is cooled to the following temperature. Here, the general deformation temperature of the continuous porous resin material is shown in Table 1. The temperature for cooling the high temperature exhaust gas in the present invention is as follows: the chemical composition of the continuous porous resin material used as the dust collecting filter, The cooling temperature is determined by the material, manufacturing conditions, usage conditions and the like.

Next, as the dust collecting filter used in the present invention, the contact angle with water droplets is 100 ° or more, and preferably 110 or more fluorine or silicon-containing continuous porous resin material consisting of a continuous porous resin material coated on the inlet side. It is a thing. Examples of the communicating porous resin material include polyolefin resins such as polyethylene and polypropylene as shown in column [1] of Table 1, polystyrene resins, polyvinyl chloride resins, polyvinylidene chloride resins, Polyvinyl fluoride resin, polyvinylidene fluoride resin, polytetrafluoroethylene resin, polyvinyl acetal resin, polyacrylic resin, polymethacrylate resin, polycarbonate resin, polyphenylene oxide resin, polyphenylene sulfide resin, polyester resin It is possible to exemplify that a resin, a polyamide resin, a polyimide resin or the like can be used. These resin materials preferably have a thickness of 1 mm to 20 mm, more preferably 2 mm to 5 mm.
It can be used as a communicating porous resin material having a sponge-like communicating hole having a pore size of 20 μm to 60 μm, more preferably 30 μm to 50 μm. These continuous porous resin materials can be produced by a known method for producing a continuous porous resin material such as a sintering method or a nonwoven fabric method. A fluorine- or silicon-containing continuous porous resin material having a contact angle with a water drop of 100 ° or more, preferably 110 ° or more on the inlet side of this continuous porous resin material, for example, polytetrafluoro as shown in Table 1 [2] Using ethylene, fluorinated ethylene-propylene copolymer, tetrafluoroethylene-fluoroalkylene vinyl ether copolymer, silicon resin, etc., the thickness is 5 μm to 100 μm, more preferably 10 μm to 50 μm, and the pore diameter is 1 μm to 10 μm, The dust collecting filter of the present invention is preferably formed and coated by a known means with a communicating porous resin material having a communicating hole of 2 μm to 6 μm. Can be obtained.

As described above, the pore diameter of the fluorine- or silicon-containing continuous porous resin material having a contact angle with a water droplet of 100 ° or more is smaller than that of the continuous porous resin material.

In addition, for silicon-containing continuous porous resin, the surface smoothness during finishing must be taken into consideration so that the contact angle during coating is 100 ° or more.

In Table 1, the deformation temperatures of the resin material that can be used as the communicating porous resin material of the present invention are described, but these are general heat deformation temperatures, and after cooling the high temperature exhaust gas of the present invention. It suffices that the temperature is less than or equal to the deformation temperature of the used material for each dust collecting filter. Therefore, as can be seen from Table 1, when polyethylene is used as the communicating porous resin material, for example, 60 to 83 ° C.
In the following, when polypropylene is used, it is necessary to cool and lower the temperature of the high temperature exhaust gas to a temperature of 85 to 110 ° C or lower, but when using a material having a high deformation temperature of 100 ° C or higher, 100 ° C Although it may be the following, it can be used even at 100 ° C. or higher.

In carrying out the present invention, it is also possible to arbitrarily use various conventionally known dust removing means such as a cyclone, a cotrel, a tap filter and the like.

<Operation> Since the present invention is configured as described above, the high temperature combustion exhaust gas is cooled to a temperature not higher than the deformation temperature of the communicating porous resin material, usually 100 ° C. or lower, by cooling with an aqueous medium, preferably quenching. Therefore, the dust contained in the exhaust gas comes into contact with the existing aqueous medium, so that even minute dust up to about 0.1 μm is adsorbed or occluded by water droplets derived from the accompanying aqueous medium. The fluorine- or silicon-containing continuous porous resin material having a contact angle with water droplets of 100 ° or more has high water repellency, and therefore has a relatively large pore diameter of about 1 μm to 10 μm and a thickness of 5 μm to 100 μm. Despite being thin, the water droplets containing the minute soot dust are captured by the wall surface without passing through the membrane surface, and only the exhaust gas that has become clean rapidly contains the fluorine or silicon-containing continuous porous resin. It passes through the material and the communicating porous resin material coated therewith.

Further, a continuous porous resin material which is a base material having a thickness of 5 μm to 100 μm, a pore diameter of 1 μm to 10 μm, and a fluorine- or silicon-containing continuous porous resin material having a contact angle with water droplets of 100 ° or more. Has a thickness of 1 mm to 20
Since the pore diameter is 20 mm to 60 μm and is larger than the pore diameter of the fluorine- or silicon-containing continuous porous resin material having a contact angle with a water droplet of 100 ° or more, When backwashing with air, there is little air resistance, and it is extremely easy to backwash the dust collecting filter, which is a continuous porous resin material as a whole.

<Example> A high density polyethylene resin is a plate-like material having a thickness of 3 mm and a continuous porous resin material having an average pore diameter of 40 μm obtained by a sintering method. One side of the material has a thickness of 40 μm and an average pore diameter of 4 μm.
The one coated with a Teflon resin having a communication hole is used for removing dust of minerals at room temperature (trade name: Sinter Lamella Filter Element HSL-450 / 8, manufactured by Helding Co., Ltd., Germany) was used as a dust collecting filter.

The combustion exhaust gas of 900 NM at 600 NM ³ / hr from a plastic test incinerator was rapidly cooled to 60 ℃ by spraying water, and this cooling gas was passed through the Teflon coated surface of the dust filter of 9.6 m ^2. While the dust particle concentration before passing through the filter was 5 g / m ³ , the outlet concentration was 0.0001.
It was less than g / m ³ . After 3 hours of operation, the dust collection filter is backwashed with air with a timer at intervals of 2 minutes so that about 1
0 kg was obtained.

When the soot dust was observed with a microscope, it was possible to observe that a large amount of fine particles having a diameter of 1 μm or less were contained.

<Effects of the Invention> According to the present invention, due to the above-described action, not only large particles but also fine particles which have been difficult to be captured by a conventional apparatus, for example, even if the diameter is about 0.1 μm to 1 μm, they are sufficiently collected. It becomes possible to generate clean exhaust gas.

Further, the dust collecting filter of the present invention can easily remove dust from the collected particles by backwashing with air and does not cause clogging. Here, the communicating porous resin material containing fluorine or silicon having a small pore diameter and a small thickness covers the communicating porous resin material having a much larger thickness and a larger pore diameter, and therefore the entire communicating porous resin material. As a dust collection filter for materials, a filter that has a sufficiently high mechanical strength when filtering exhaust gas from a combustion furnace and does not damage the fluorine- or silicon-containing continuous porous resin material, and that can be used for a long time Is. After all, the entire device is small and inexpensive, and it is possible to continuously discharge clean exhaust gas for a long time.
The profit is great.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view of the present invention. FIG. 2 shows another example B ′ of the cooling step B of FIG. 1, and FIG. 3 shows another example B ″ of the cooling step B of FIG. 1. A: combustion furnace, B: cooling means, C : Dust removal means, D: Chimney,
1: Burning high temperature exhaust gas, 2: Cooling aqueous medium, 3: Spray, 4: Cooling exhaust gas flue, 5: Dust collecting filter, 6: Fluorine- or silicon-containing continuous porous resin with a contact angle of 100 ° or more with water droplets Materials, 7: communicating porous resin material, 8: flue, 9: air pipe, 10: soot and water drop outlet, 11: attraction fan, 12: wetted wall membrane, 13: filler, 14: pump, 15: Heat exchanger.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akira Suganuma 1-28-29-205 Hongo, Bunkyo-ku, Tokyo (56) References 62-43621 (JP, U) 52-92451 JP, U) Actual public 47-35941 (JP, Y1) Actual public 50-3350 (JP, Y2)

Claims (4)

[Claims] 1. A high temperature exhaust gas of a combustion furnace is cooled to a temperature lower than a deformation temperature of a communicating porous resin material by using an aqueous medium,
Next, the generated exhaust gas containing water droplets containing fine soot dust is cooled to a thickness of 5 μm to 100 μm and a pore diameter of 1 μm.
To 10 μm, and the inlet side is coated with a fluorine- or silicon-containing continuous porous resin material having a contact angle with water droplets of 100 ° or more, thickness 1 mm to 20 mm, pore diameter 20 μm to 6
A combustion furnace exhaust gas dust removal method, which comprises passing through a dust collection filter made of a 0 μm continuous porous resin material, and applying backwashing air to this dust collection filter. 2. The communicating porous resin material is a polyolefin resin, polystyrene resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl fluoride resin, polyvinylidene fluoride resin, polytetrafluoroethylene resin, Polyvinyl acetal resin, polyacrylic resin, polymethacrylic resin, polycarbonate resin,
The combustion furnace exhaust gas dust removal method according to claim 1, wherein the combustion furnace exhaust gas dust removal method comprises a resin selected from a polyphenylene oxide resin, a polyphenylene sulfide resin, a polyester resin, a polyamide resin, and a polyimide resin. . 3. A fluorine- or silicon-containing continuous porous resin material having a contact angle with water droplets of 100 ° or more is polytetrafluoroethylene, a fluorinated ethylene-propylene copolymer,
The combustion furnace exhaust gas dust removal method according to claim 1 or 2, which is made of a synthetic resin selected from tetrafluoroethylene-perfluoroalkylene vinyl ether copolymer or a silicone resin. 4. A means for cooling an exhaust gas of a combustion furnace using an aqueous medium to a temperature lower than a deformation temperature of a communicating porous resin material, the generated exhaust gas containing water droplets containing fine soot dust, Thickness 5 μm to 100 μm, Pore diameter 1 μm
To 10 μm and the contact angle with water droplets is 100 ° or more, and fluorine or silicon-containing continuous porous resin material is coated on the inlet side, the thickness is 1 mm to 20 mm, and the pore diameter is 20 μm to 60.
A combustion furnace exhaust gas dust remover comprising: a dust removing means for passing through a dust collecting filter made of a continuous porous resin material having a diameter of μm; and means for applying backwashing with air to the dust collecting filter.