Gas adsorbing element and method for forming same

Abstract

A gas adsorbing element is formed into a honeycomb-shaped laminate having many small channels penetrating from one end surface to the other and in which hydrophobic high silica zeolite powder is exposed on the walls of the small channels. The hydrophobic high silica zeolite is, for example, a zeolite which is produced by removing most of the aluminum component from an ordinary zeolite. In forming the honeycomb-shaped laminate, it is favorable that non-flammable sheets are laminated and the laminate is impregnated with a dispersion of high silica zeolite powder and with an inorganic binder, and that the high silica zeolite powder is fixed in fiber gaps and on the surface of the non-flammable paper. It is desirable that the non-flammable sheet is a low density inorganic fiber paper and is baked either before or after forming the honeycomb-shaped laminate. This element adsorbs little water vapor even when the process air is highly humid, and is able to adsorb and remove organic solvent vapor and bad odor material in the air with high efficiency.

Description

[0001]This application is a continuation application of application Ser. No. 09 / 433,272, filed Nov. 3, 1999, now abandoned, which was a reissue application of U.S. Pat. No. 5,348,922.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to a gas adsorbing element which selectively adsorbs and removes active gases contained in inert gases such as air, especially harmful gases such as organic solvent vapor, bad odor material, etc., to obtain clean inert gases such as air.[0004]2. Description of the Prior Art[0005]Zeolite is a molecular sieve and is used as an adsorbent because it mainly consists of aluminosilicate. Zeolite also selectively adsorbs water and other gas molecules such as organic solvent vapor, in accordance with the diameter of the molecules, making good use of the difference in diameters of micropores which are formed by elimination of crystal water.[0006]A rotative reactivation type dehumidifier element has been proposed in Japan...

AI Technical Summary

Benefits of technology

[0009]In the present invention, a gas adsorbing element is provided in which zeolite is used as an adsorbent having a high silica content to impart a hydrophobic property, and which is formed into a block, i.e., a honeycomb-shaped laminate, having many small channels penetrating from one end surface to the other. The high silica zeolite is exposed on the surface of the small channels. The gas adsorbing element of the present invention does not adsorb vapor in inert gases such as air which contain water vapor and organic solvent vapor and / or bad odor material, and has the ability to efficiently adsorb the organic solvent vapor and the bad odor material.

[0017]In the present invention, a gas adsorbing element is formed into a block having many small channels penetrating from one end surface to the other, i.e., a honeycomb structure, so that the above-mentioned high silica zeolite having a hydrophobic property efficiently adsorbs and separates organic solvent vapor and bad odor material. For forming the honey-comb structure into a block there is a method, for example, in which the above-mentioned high silica zeolite is mixed with inorganic binder such as kaolinite and is formed into a honeycomb structure by extruding, press forming, etc. There is another method in which a sheet carrier such as paper or cloth is formed into a honeycomb block and high silica zeolite powder is bound on and in the sheet carrier with an inorganic binder either before or after the formation of the block. In the latter method the contacting area of high silica zeolite with process gas is larger and is utilized more efficiently. A porous sheet formed of fibers such as paper, cloth and non-woven fabrics are preferable as a sheet carrier than one with a smooth surface and without a permeating property such as a metal sheet and a plastic sheet. This is because high silica zeolite is carried not only on the sheet surface but also in the fiber gaps. Especially bulky sheets of fibers having a high aperture rate are desirable. During gas adsorption, desorption / reactivation is necessary. For desorption, a pressure swing method which does not need heating can be used, but desorption / reactivation by heating can be performed more easily and with simpler equipment. For heating reactivation, the element should be heat resistant and nonflammable, and therefore inorganic fiber papers are used which have no danger of catching fire. These inorganic fiber papers include paper formed from ceramic fibers, rock fibers, slag fibers, or glass fibers, or paper mainly consisting of a mixture of these fibers. The use of asbestos fiber, which is also an inorganic fiber and does not pose a danger of catching fire, is not preferable because asbestos is harmful to the health of humans.

Problems solved by technology

Therefore, when the absolute humidity of process air is high, zeolite cannot efficiently adsorb and separate organic solvent vapor or bad odor material.

However, it is flammable and has a danger of catching fire when hot air about 130° C. is used for reactivation.

Also some types of adsorbed solvent generate high adsorption heat and the adsorbing element has a danger of catching fire.

Thus, it is extremely difficult to use.

This active carbon element, however, has a defect such that during high temperature regeneration hot air cannot be used; rather, superheated water vapor should be used for regeneration.

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