KR20030026668A - Metal thin-film filter - Google Patents

Abstract

PURPOSE: Provided is a metal thin film filter having high corrosion resistance at a high temperature. CONSTITUTION: The metal thin film filter essentially comprises 10-40 wt.% of chrome and 1-15 wt.% of aluminium, and includes nickel or iron as a remainder and some contaminants, wherein the metal thin film filter has a thickness less than 500 micrometers and pores less than 100 micrometers in size.

Description

Metal Thin Film Filter {METAL THIN-FILM FILTER}

The present invention relates to a filter formed of a metal thin film, and more particularly, to a metal thin film filter having a plurality of micropores perforated using a photoetching technique.

Dust emitted from industrial sites pollutes the environment when it is released into the atmosphere as it is, so it is purified through a dust collector equipped with a filter, and then released into the atmosphere.

In general, filters used to remove dust have been used in the form of woven or nonwoven fabrics of fibrous material.

As the fibrous material used in the filter, polyester fiber is most widely used, and polyethylene, polypropylene, acrylic, nylon, nomex, glass fiber and the like have been used.

These fibrous filters are mainly in the form of filter cloth, and dust generated in the factory is removed while most particles are removed from the surface of the filter cloth and some are passed through the inside of the filter cloth. In addition, the gas introduced into the dust collector is purified through the pores of the filter cloth and discharged into the atmosphere.

Representative industrial processes to remove dust using such filter cloth include steel process, incineration process, cement process, chemical process, power generation process, papermaking process, and coke process.

However, these fibrous filter cloths are useful for trapping and removing dust, but they cannot be used above 250 ℃ due to the material characteristics of being made of fibers that are weak against heat. Not available at Therefore, in order to prevent the operation at high temperature, it is necessary to install a pretreatment facility such as a cooling facility, and thus there is a problem in that the design and construction, maintenance, and operation costs increase.

In addition, since a large amount of moisture is contained in the exhaust gas, clogging of the filter cloth occurs due to this moisture, and moisture is also contained in the exhausted air.

Due to such clogging and moisture in the deaeration air, the water condensation of the filter cloth and the increase in the differential pressure reduce the dust collection efficiency, reduce the life of the bag containing the filter cloth, increase the replacement rate, and increase the overall operating and maintenance costs. .

In particular, the dust collecting device using the fibrous filter cloth may cause instantaneous rupture due to weakening of the mechanical and thermal durability of the filter cloth for a long time, and in this case, there is a risk of an accident.

Therefore, there is a need for developing a filter having physical properties that can be used at high temperatures, and such a filter may be advantageous in terms of physical properties.

As a metal thin film filter formed of a metal thin film instead of a fibrous filter cloth, there is a Korean Patent Application Publication No. 2000-0072210, but only conceptual information is disclosed. However, according to the above publication, no specific experimental data is presented, and durability and dust collection efficiency are low, and thus cannot be put to practical use.

In order to realize the practical use of the metal thin film filter, the exhaust gas has to be purified to a satisfactory level. Therefore, dust collection efficiency of 95% or more required in general industrial processes is required, and diesel engines require dust collection efficiency of 60% or more.

In addition, the metal thin film filter has a higher performance when the pressure drop is lower during operation, but the condition of the process should not exceed the allowable pressure of the metal thin film filter. Therefore, in general, the pressure drop in the dust collector main body is 100-150 mmH2O or less in the industrial dust collecting process. Therefore, it is preferable to operate the gas at 100-150 mmH2O or less. .

In addition, the metal thin film filter must be strong thermal and chemical durability so that it can be used for a long time.

However, the steel sheet mainly used as a material of the metal thin film filter has a short lifespan because of low resistance to corrosion gas even at room temperature.

In addition, the stainless steel sheet adopted to prevent corrosion also has a problem of short life because it corrodes quickly under high temperature corrosion conditions.

Therefore, the present invention has been made to solve the problems of the prior art, and an object thereof is to provide a metal thin film filter having a high corrosion resistance at room temperature and high temperature.

In the metal thin film filter formed with a plurality of micropores in order to achieve the above object, the metal thin film filter is 10 to 40% by weight of chromium, 1 to 15% by weight of aluminum, the balance comprises one or more nickel or iron Provided is a metal thin film filter, which is composed of an inevitable component.

The metal thin film filter of the present invention is a metal thin plate of 500 μm or less, and micropores of 100 μm or less penetrate the metal plate by a method such as photoetching. Tens to millions of micropores are formed.

As described above, the metal thin film filter in which the micropores are formed may be used as one layer or may be stacked and used in a plurality of layers.

Hereinafter, the present invention will be described in detail.

The composition of the metal thin film filter according to the present invention is composed of any one of the following three compositions.

First: nickel; 5-20% by weight, chromium; 10-40% by weight, aluminum; 1-15% by weight, balance with iron and inevitable impurities.

Second: chrome; 10-40% by weight, aluminum; 1-15% by weight, balance with nickel and inevitable impurities.

Third: chromium; 10-40% by weight, aluminum; 1-15% by weight, balance with iron and inevitable impurities.

As in the composition of the alloy, aluminum is essentially added to the iron-chromium alloy, iron-nickel alloy or nickel-chromium alloy. The aluminum added in this way is combined with chromium to form a stable oxide.

Since the oxide thus formed acts as a stable layer, the weight change of the alloyed material does not occur significantly even in a high temperature oxidizing atmosphere or a high temperature sulfiding atmosphere. Therefore, the formation of such a stable oxide layer in the filter greatly extends the life of the filter. Stable oxidation resistance in the present invention is mainly provided by an alumina film.

In the present invention, chromium (Cr) is an important element for achieving heat resistance and oxidation resistance, when the content of chromium is low, the alumina film is difficult to maintain oxidation resistance due to the decrease in adhesion and protection properties, and when the chromium content is excessive, toughness Since the chromium content of the metal thin film filter is reduced, it is preferable that the content is 10% by weight to 40% by weight.

In the present invention, aluminum is an element that combines with oxygen to form an alumina oxide layer and improves oxidation resistance, so that the oxidation resistance is hardly improved when the aluminum content is low, and the metal thin film filter has a high workability and toughness when the aluminum content is high. The aluminum content of is preferably 1% by weight to 15% by weight.

In addition, the aluminum used here is applied as a base metal in a calorizing process in which aluminum is diffused into the base metal, so that the composition of the aluminum can be changed so that the aluminum content is relatively high near the surface of the metal thin film. .

Calorizing is a method of heating a base metal to diffuse powder aluminum onto the surface of the base metal to improve the alumina layer.

Thus, the base metal subjected to the colorizing is greatly improved in oxidation resistance and heat resistance.

On the other hand, it is preferable to add 5 wt% to 20 wt% of nickel since it is difficult to maintain oxidation resistance when the content is added and the workability is poor due to brittleness.

The balance also consists of iron or nickel and contains other unavoidable impurity components.

Example

In the present invention, a metal thin film specimen having a weight of 10 g was manufactured to test the durability according to the component content.

The metal thin film specimens were 120 μm thick and were exposed to acidic gas at 25 ° C. and 300 ° C. for 240 hours, and then the weight of the specimen was measured to determine the reduced weight.

At this time, the atmosphere in which the specimen is exposed is 1500 ppm of sulfur dioxide (SO ₂ ) gas, the moisture content is 10%.

The reduced weight by measuring the weight is a suitable method for measuring the durability of the metal thin film specimens with the corroded and lost parts.

In other words, as the weight of the specimen decreases, corrosion resistance decreases, so the durability is high.

Table 1 shows the reduced weight of the metal thin film specimen measured at 25 ℃, Table 2 shows the reduced weight of the metal thin film specimen measured at 300 ℃.

Psalm Number Iron (% by weight) Chromium (% by weight) Nickel (wt%) Aluminum (% by weight) Reduced weight (g) Comparative Material 1 Balance 17 14 - 2.1 Comparative Material 2 - 25 Balance - 1.1 Comparative Material 3 Balance 20 - - 1.4 Invention 1 Balance 16 13 6 0.5 Invention 2 Balance 17 14 One 0.9 Invention 3 Balance 10 14 6 0.5 Invention 4 Balance 17 20 6 0.45 Invention 5 - 23 Balance 6 0.33 Invention 6 - 10 Balance 6 0.45 Invention 7 Balance 25 - 6 0.3 Invention Material 8 Balance 10 - 6 0.4

Psalm Number Iron (% by weight) Chromium (% by weight) Nickel (wt%) Aluminum (% by weight) Reduced weight (g) Comparative Material 1 Balance 17 14 - 2.8 Comparative Material 2 - 25 Balance - 1.6 Comparative Material 3 Balance 20 - - 1.95 Invention 1 Balance 16 13 6 0.85 Invention 2 Balance 17 14 One 1.35 Invention 3 Balance 10 14 6 0.7 Invention 4 Balance 17 20 6 0.6 Invention 5 - 23 Balance 6 0.42 Invention 6 - 10 Balance 6 0.7 Invention 7 Balance 25 - 6 0.4 Invention Material 8 Balance 10 - 6 0.5

As shown in Table 1 and Table 2, first, when comparing the reduced weight measured at 25 ℃ and 300 ℃ it can be seen that the durability of the metal thin film specimen is lowered as the temperature increases.

Comparing the inventive material and the comparative material of the present invention, the results measured at 25 ° C. show that the reduced weight of the invention is less than 1 g.

In addition, the reduced weight is less than 1 g in the invention except when 1% by weight of aluminum is added as a result of the measurement at 300 ° C.

Of course, even when 1% by weight of aluminum is added, since the reduced weight is less than that of the comparative material, it can be seen that aluminum improves durability.

Therefore, chromium is 10% by weight to 40% by weight, aluminum is 1% by weight to 15% by weight, and the metal thin film filter whose residue is made of an unavoidable component including iron or nickel is maintained at high temperatures.

As described above, according to the present invention, since the metal thin film filter is maintained at high temperatures, production costs are reduced by saving maintenance costs required to replace the metal thin film filter.

In addition, the productivity is improved because it takes no time to replace the metal thin film filter.

Claims (2)

In the metal thin film filter formed with a plurality of micropores, The metal thin film filter is 10 to 40% by weight of chromium, 1 to 15% by weight of aluminum, the balance is made of nickel or iron and contains other unavoidable impurities, the thickness is 500㎛ or less, less than 100㎛ micropores Metal thin film filter, characterized in that formed a large number. The method of claim 1, The metal thin film filter, characterized in that 5% by weight to 20% by weight of nickel is further added to the composition when the balance is iron.