JPH0677668B2 - Method for manufacturing moisture exchange element - Google Patents

Description

The present invention relates to a block having a large number of small pores formed by a solid moisture absorbent that reversibly adsorbs moisture, and desorbs the treated gas into the small pores. The present invention relates to a method for manufacturing a dehumidifying or other moisture exchanging element for obtaining a dehumidified gas, for example, dry air, by alternately passing a working gas.

2. Description of the Related Art In the patent application No. 206849, “Method for manufacturing a moisture exchange element” in 1984, the applicant of the present patent claims that a large number of small through-holes are formed by laminating papers with a low density using inorganic fibers such as ceramic fibers. To the shape of a moisture exchange element having, the paper is impregnated with water glass before or after the molding step, and after the molding step, concentrated and dried until it becomes a water water glass with a water content of 3 to 20%,
It has been proposed to obtain a strong moisture exchange element having an inorganic fiber skeleton as a main component and silica erogel as a main component by soaking in an acid to form silica hydrogel, washed with water and dried.

The inorganic fiber paper used in this element for moisture exchange contains a small amount of wood pulp or other vegetable pulp or synthetic fiber pulp for the convenience of paper making, while air or other treated gas is used as the element in the dehumidification operation. Alternately, a dehumidifying step of adsorbing the moisture in the gas to the hygroscopic agent in the element through a small through hole and a regeneration step of desorbing the adsorbed moisture by passing a high temperature desorption gas through the small through hole of the element. Since the organic components such as the above-mentioned valves contained in the inorganic fiber paper may be ignited in the regeneration process in which the device is exposed to high temperature, 400% in the presence of air in the final process of device production.
A method of removing the organic component in the device by heating and baking at around ℃ is used.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In contrast to the so-called heat swing method, which is a dehumidification method that uses a high-temperature gas for desorption, there is a pressure swing method that performs adsorption and desorption by changing gas pressure without using heat ( For example, see Kenichiro Suzuki and Hiroshi Kitagawa, "Pressure Swing Cycle System", published by Kodansha Ltd. on May 1, 1983). This pressure swing method adsorbs moisture contained in the treated air to the moisture absorbent particles by pressurizing the treated air and passing through a layer of the moisture absorbent particles packed in the tower, and the normal temperature regeneration air is By passing the layer of hygroscopic agent particles under reduced pressure, moisture is released from the hygroscopic agent particles to regenerate the hygroscopic agent. The device using this pressure swing method requires only a small amount of adsorbent because the adsorption / desorption switching time is short and the total amount of adsorbed water is small, and the adsorption / desorption switching time in the thermal swing method is 6 hours. On the other hand, assuming that the above switching time in the pressure swing method is 5 minutes (however, regardless of the diameter and depth of the adsorbent layer and regardless of the size of the particles), the negative water content of both is 72: 1 and the pressure swing. It seems that the method can be designed to be extremely small, but the pressure swing method also has the minimum required adsorbent layer length, and the effective flow rate for adsorption is generally limited to 10 to 25 cm / sec. In order to obtain the above, it is necessary to make the cross-sectional area of the adsorbent layer as large as possible, and a column diameter that is substantially the same as that of the adsorption device by the heat regeneration method is required, and the device cannot be downsized. Also, if the particles are made smaller to increase the surface area of the hygroscopic agent particles, the particles are liable to be crushed by the flow of the processing air or the regenerated air and the passage of the air becomes gradually difficult, and 10 to 25 cm.
In the practical wind speed range of / sec., The tower cannot be made compact by increasing the effective surface area, that is, atomizing the particles of the hygroscopic agent.

In order to avoid the above-mentioned difficulties due to the pulverization of the hygroscopic agent, it is possible to solve the problem by using the honeycomb molded body containing silica erogel as a main component shown in the above-mentioned prior application. However, there are various problems when trying to increase the speed of moisture absorption / regeneration by increasing the amount suitable for. That is, the above-mentioned moisture exchange element has a wavelength of 3 mm or more and a wave height.
Although it is possible to manufacture by laminating corrugated paper of 1.5 mm or more and flat paper, the size of the small through holes is further reduced, for example, the wave wavelength of corrugated paper is reduced to 1 to 2 mm and the wave height is reduced to about 0.4 to 1 mm. If an attempt is made to increase the effective surface area per unit volume, it becomes difficult to form corrugated paper with paper containing inorganic fiber as the main component, while on the other hand, when dipping a water glass aqueous solution and acid after lamination molding, such liquid Since the influence of surface tension becomes significantly large, especially in the case of water glass impregnation, the viscosity of the water glass aqueous solution is high, so water glass causes clogging of the small through-holes of the honeycomb formed body in the process of dipping and impregnation, and the subsequent chemical The treatment process becomes impossible, that is, contact between water glass and acid on many small pore walls, that is, formation of silica gel becomes difficult,
Therefore, it is not possible to manufacture a moisture exchange element, and it is difficult to remove the salt generated as a by-product from the small pores, and even if the acid concentration in the small pores is low, it can be removed from outside the small pores. Acid cannot be replenished, and the water water glass or semi-solid water glass adhering to the small pore walls elutes into the liquid, causing a silica gel formation reaction in the liquid, and the generated silica gel flows out. Wasteful, or it is not possible to obtain the required molded product by closing the small through holes, and even if a molded product is obtained, the manufacturing cost per volume of the moisture exchange element increases the amount of raw material used. 3mm including the above wavelength,
The wave height is 2 to 3 times as high as that of a wave height of about 2 mm, and practically impossible.

Means for Solving the Problems The present invention eliminates the above-mentioned drawbacks, and an object of the present invention is to produce a moisture exchange element having a small diameter of a small through hole which is particularly suitable for pressure swing dehumidification. That is, pulp, that is, organic fibers are added to inorganic fibers to form a mixed paper, and the thickness is 0.1 to 0.3.
mm paper is impregnated with water glass, and the water glass is semi-dried until the paper can be corrugated.
0.4 to 3.0 mm, preferably wavelength 1.0 to 4.0 mm, wave height 0.4 to 2.0
mm corrugated corrugated paper and flat paper are soaked in acid to generate silica hydrogel by reaction between water glass and acid, washed with water and reacted with excess acid and silica hydrogel dispersed in liquid After removing the by-products, the silica hydrogel adhering to the paper is dried to form silica erogel, and flat paper and corrugated paper are alternately laminated to form an element having a large number of small holes, and the paper is A feature is to obtain a moisture exchange element having a silica erogel as a main component as a skeleton. Hereinafter, embodiments will be described in detail with reference to the drawings.

EXAMPLE FIG. 1 shows an example of the method of the present invention and an apparatus used for carrying out the method. In the figure, 1 and 1 are water glass aqueous solution impregnating apparatuses, respectively, water glass aqueous solution containers 1a and 1a, and guide rollers 1b and 1b. The squeezing rollers 1c, 1c are provided, and the water glass aqueous solution 2, 2 is put in the water glass aqueous solution container 1a, 1a to immerse part or all of the guide rollers 1b, 1b. 3 and 3 are dryers, and 4 and 4 are a pair of molding gears having a desired tooth profile and mesh with each other. Reference numerals 5 and 5 are acid impregnating devices, which are composed of acid containers 5a and 5a and guide rollers 5b and 5b, respectively. The acid containers 5a and 5a are filled with acid 6 and 6 and part or all of the guide rollers 5b and 5b are immersed. . 7 and 7 are water washing devices, each consisting of an aqueous solution 7a and 7a, guide rollers 7b and 7b, and spray nozzles 7c and 7c. Water 8 and 8 are put in water containers 7a and 7a, and part or all of the guide rollers 7b and 7b are put. Soak. 9, 9 is a dryer, 10 is an adhesive coating device, which is composed of an adhesive container 10a and an adhesive coating roller 10b, and 11 is also an adhesive coating device, which is composed of an adhesive container 11a and an adhesive coating roller 11b. Adhesive on the containers 10a and 11a
Insert 12 and 12 and immerse a part of the adhesive application rollers 10b and 11b. Incidentally, reference numerals 13, 13 ... In the figure are guide rollers.

Ceramics fiber 100 parts (all weight parts below), pulp (wood pulp or synthetic pulp) 20-50 parts, glass fiber 0-10 parts, binder 3-10 parts, thickness 0.1-0.3
Prepare porous paper 14 and 15 with a diameter of 0.5 mm and a density of 0.5 g / cm ³ or less by rolling them into rolls as shown in the figure.
Water glass aqueous solution 2,2 is passed under 1b to squeeze and remove excess adhered water glass aqueous solution by squeezing rollers 1c, 1c, and then water glass solution impregnated by dryer 3, 3 45% Japanese water water glass or dried until it becomes a semi-solid state, guide one paper 14 to the meshing part of the molding gears 4, 4 and
Without corrugated paper 4a with 1.0-1.4mm, wave height 0.4-2.0mm, corrugated paper
14a and the flat paper 15 are passed under the guide rollers 5b, 5b, respectively, and immersed in a 15% aqueous solution 6 of sulfuric acid to form silica hydrogel by the reaction between water glass and sulfuric acid, and then under the guide rollers 7b, 7b. Through-product sodium sulphate and excess sulfuric acid as well as silica hydrogel not attached to the paper are treated with water 8,
8 and the spray nozzles 7c, 7c to wash and remove with water sprayed and dried by the dryer 9,9, water glass or other appropriate adhesive on the corrugated crests of both sides of the corrugated paper 14a with adhesive application rollers 10b, 11b Moisture exchange element mainly composed of silica erogel and coated with 12, 12 and laying flat paper 15 and corrugated paper 14a and wrapping around core material 16 and drying adhesive 12 if necessary To get

As the water glass to be used, any of No. 1, No. 2, and No. 3 water glasses (sodium silicate) can be used, and potassium silicate may be used. The acid used can theoretically be any acid stronger than silicic acid, but sulfuric acid is most preferable in view of cost, working environment and the like. On the other hand, as the paper to be used, in addition to the above-mentioned ceramic fibers, glass fibers, slag fibers, carbon fibers, asbestos fibers, mountain fibers such as mountain bark or a mixture thereof and pulp, for example, hardwood, wood pulp obtained from softwood, etc.,
Ganbi, Kozo, Mitsumata, Straw, Esparto, Bamboo, Burlap, Cannabis, Manila hemp, flax, and other plant fiber pulp, beaten acrylic fiber, polyethylene fiber, synthetic fiber such as polyamide fiber When used for pressure swing dehumidification, which is the main purpose of the present invention,
Since heat resistance and fire resistance are not required, the content rate of organic fibers can be appropriately increased. When heat resistance is required, the content of organic components in the above-mentioned paper should be slightly lower, for example 10
40% or less after papermaking, preferably after impregnation with an appropriate amount of an inorganic binder such as silica gel or alumina sol and drying.
It is used by firing at 0 to 500 ° C to remove organic substances. The calcined paper is brittle and cannot be corrugated as it is, but if it is impregnated with water glass and dried to such an extent that it has flexibility, the viscosity of water glass enables corrugation of paper.

An example of a cylindrical moisture exchange element manufactured by the method of FIG. 1 is shown in FIG. An example of a parallel flow type moisture exchange element obtained by drying the papers 14a and 15 by the dryers 9 and 9 and cutting them into appropriate dimensions and laminating in the above method is shown in FIG.

The function of the present invention is as follows. The moisture exchanging element obtained in the present invention has a large number of small pores through which treated air is pressurized so that moisture in the treated air is adsorbed by silica gel on the walls of the small pores, followed by regeneration at room temperature. Air for use is passed through the small through holes under normal pressure or reduced pressure to desorb the moisture adsorbed on the silica gel, and the above adsorption step and regeneration step are repeated alternately. The same applies to the case of treating an inert gas other than air.

Although the pressure swing method has been described above, the pressure swing method may be used for a fixed type or a rotary type heat swing method. FIG. 4 shows an embodiment in which a dehumidifier is assembled by using a cylindrical moisture exchange element as a rotary type. The moisture exchange element 17 is rotatably held in a casing 18 by a separator 19 and an adsorption zone 20 and a regeneration zone are provided.
21, the element 17 is rotated by the geared motor 22 and the drive belt 23 to feed the treated air 24 into the adsorption zone 20 and the heated regeneration air 25 into the regeneration zone 21, and the treated air 24
Is continuously dehumidified to obtain dry air 26, and moisture adsorbed on the element is desorbed continuously or intermittently in the regeneration zone 21 to regenerate the element. In FIG. 4, 27 is a heater for heating the air for regeneration, 28 is a pulley, 29 is a tension pulley, and 30 is a rubber seal.

EFFECTS OF THE INVENTION Since the present invention is configured as described above, shrinkage during drying of silica gel is very small as in the case of the moisture exchange element of the prior application, and there is no risk of cracking silica silica gel or breaking into fine pieces and forming a matrix. A molded product of silica erogel firmly adhered to paper is obtained. In the production of the element for exchanging moisture of the present invention, it is easy to form corrugated paper having a small wavelength and wave height required for the pressure swing method if the organic content of the paper is increased, and the size of the small through holes in the product is small. Therefore, the strength is high, and the pressure resistance of the moisture exchange element of the previous application is 2.0 kg /
The device of the present contrast been filed in cm ² is reached 5.5 kg / cm ^2, can also be sufficiently resistant to sudden fluctuations other mechanical Shiyotsuku when the ambient pressure is high or ambient pressure, in a high pressure vessel Dehumidification or adsorption / desorption cycle is 5
It is particularly suitable for pressure swing dehumidification, which is as short as 20 minutes. When used for dehumidification by the pressure swing method, high temperature is not used in the regeneration cycle, so even if air is used as the regeneration gas, there is no risk of the element burning out, and therefore paper with a large amount of organic matter is used. Since it is manufactured and there is no need for firing, it can be manufactured easily and inexpensively. By reducing the wavelength and wave height of the corrugated paper, the effective surface area per unit volume of the device is remarkably widened, and comparing the effective surface area with the conventional pressure swing device packed with granular adsorbent in the column. There is a marked difference like this. When the dehumidifying effect of the hygroscopic agent is examined by this, the dryness of the air at the outlet can be calculated from the theoretical equation of the breakthrough curve of the linear equilibrium system as C = C ₀ exp (−K _F a _v z / u) where C: outlet water concentration [G / m ³ ] C ₀ : Inlet water concentration [g / m ³ ] K _F : Overall mass transfer coefficient [cm / sec.] _Av : Effective surface area [m ² / m ³ ] z: Bed height [cm] u: flow velocity [cm / sec.], and when the device of the present application is filled, the flow velocity u is doubled by doubling the effective surface area a _v as compared with the case where the conventional silica gel particles are filled. However, since the dryness C of the air at the outlet is the same, in order to obtain the same performance, the device of the present application requires a much smaller volume than the conventional silica gel particles, and the pressure swing tower is made compact. The speed of dehumidification and regeneration can be increased. Further, since the element of the present application is integrally formed in a honeycomb shape having a large number of small through holes, even if the flow velocity of the gas passing therethrough is increased, there is no crushing or pulverization due to the flow of particles, and Since it dehumidifies by passing the processing gas through a large number of small holes, the pressure loss is much smaller than that in the case of passing the hygroscopic agent particle layer. FIG. 5 shows the pressure loss of the spherical silica gel layer and the honeycomb type dehumidifying element according to the present invention. In the figure, A is a spherical silica gel having a particle size of 2.0 to 3.4 mm, B is a spherical silica gel having a particle size of 3.4 to 4.8 mm, and C is a spherical silica gel. Is spherical silica gel having a particle size of 4.8 to 7.0 mm, D is the wavelength of the present invention of 1.5 m
Unit length [m] of the element formed by corrugated paper with m and wave height of 2.0 mm
Indicates the pressure loss per hit.

The results of measuring the moisture absorption performance of the moisture exchange element obtained according to the above example are shown in FIGS. 6 to 9. FIG. 6 shows 40-45% of No. 1 water glass (silicon oxide to sodium oxide 2.1: 1) and No. 3 water glass (silicon oxide to sodium oxide 3.1: 1) using the same paper according to the above example. Aqueous solution and 1
Moisture absorption amount relative to the amount of silica gel adhered when silica gel is adhered under the conditions of silica gel adhesion amount 19.4 water glass 149.4% silica gel adhesion amount 3 water glass 172.5% in the element for moisture exchange obtained by using 5% sulfuric acid. wt%], Fig. 7 shows the relative humidity of a humidity exchange element obtained by immersing the same paper in a 40-45% aqueous solution of No. 1 water glass and reacting it with 15% sulfuric acid and hydrochloric acid to mold it. Moisture absorption amount [wt%] relative to the amount of adhered silica gel measured at 75%. Figures 8 and 9 show 40 of No. 1 water glass.
Immersed in 45% aqueous solution and reacted with 15% sulfuric acid and hydrochloric acid Water glass acid / silica gel adhesion amount 1 Sulfuric acid 141.5% 1 hydrochloric acid 138.6% Equilibrium moisture absorption on the surface area of paper when silica gel is adhered The amount [g / m ² ] and the equilibrium moisture absorption amount with respect to the paper weight are shown. The temperature during the test is 18 to 23 ° C in all cases. As is clear from this data, the moisture absorption performance was almost as good as that of the moisture exchange element of the prior application.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, FIG. 1 is an explanatory view showing an outline of a method for manufacturing a moisture exchange element of the present invention and an apparatus used therefor, FIG. 2 is a cylindrical moisture exchange element, and FIG. The figure is a perspective view of a parallel flow type moisture exchange element, FIG. 4 is a partially cutaway perspective explanatory view of a rotary dehumidifier using the cylindrical moisture exchange element of FIG. 2, and FIG. FIG. 6 is a graph showing the pressure loss between the moisture exchange element of the present invention and the spherical silica gel packed layer, and FIGS. 6 to 9 are graphs showing the moisture absorption performance of the moisture exchange element of the present application. 1 to 3, 1 is a water glass impregnation device, 3 and 9 are dryers, 4 and 4 are molding gears, 5 is an acid impregnation device, and 7 is a water washing device, 1
Reference numerals 0 and 11 denote adhesive coating devices, and 14 and 15 denote papers produced by mixing pulp with inorganic fibers such as ceramics fibers and pulp.

Claims (1)

[Claims] 1. A paper impregnated with water glass having a thickness of 0.1 to 0.3 mm, which is made by mixing inorganic fiber such as ceramic fiber and pulp,
The water glass is semi-dried to the extent that paper can be corrugated, corrugated corrugated paper having a wavelength of 1.0 to 4.0 mm and a wave height of 0.4 to 2.0 mm and a plane paper are each immersed in an acid to form silica hydrogel, and washed with water. A method for producing a moisture exchange element, characterized in that after drying, flat paper and corrugated paper are alternately laminated and molded to obtain an element having a paper skeleton and silica gel as a main component.