JP3345596B2 - Adsorbent for moisture exchange - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moisture exchange adsorbent such as a dehumidification adsorption sheet and a moisture exchange honeycomb adsorption element such as a dehumidification adsorption element or a total heat exchange element for exchanging moisture and sensible heat (hereinafter referred to as a moisture exchange element). Call it body)
It is about.

[0002]

2. Description of the Related Art Zeolite and other molecular sieves,
Honeycomb elements for dehumidification or total heat (moisture and sensible heat) exchange using an inorganic desiccant such as silica gel or lithium chloride have been conventionally used. In addition, the present applicant impregnated and immobilized water glass on the laminate, and then synthesized a silica gel or metal silicate gel using a chemical reaction with an acid or metal salt aqueous solution (Japanese Patent Publication No. 1-261414, Japanese Patent Publication No. Hei 5-256). 8
1831).

[0003] These adsorbents for dehumidification are used for removing moisture from air, nitrogen gas and other gases in various fields such as semiconductor industry, film industry, food industry and military industry. Honeycomb elements for total heat exchange are used for exchanging moisture and sensible heat as total heat exchangers for buildings, factories and homes.

[0004]

The above-mentioned conventional adsorbents such as zeolite and other molecular sieves and silica gel are dispersed in a binder such as silica sol and alumina sol, and the fine particles of the inorganic moisture absorbent are dispersed by dipping the honeycomb element in the dispersion. A method of impregnating and fixing the inside of a sheet constituting a honeycomb element, or fixing a fine particle of an inorganic moisture absorbing agent to a sheet constituting a honeycomb element by using a binder, and then laminating and forming into a honeycomb shape is performed.

In this method, the binder does not contribute to the adsorption of moisture, but rather reduces the adsorption area of the adsorbent and lowers the adsorption performance. The present invention aims to obtain a high-performance hygroscopic sheet and a honeycomb element for exchanging moisture by simple means.

[0006]

According to the present invention, a hydrophilic organic polymer electrolyte is added to a silica sol containing silica particles having a number of stable silanol groups on the surface and having a particle diameter of about 120.degree. A moisture exchanger is obtained by impregnating or coating a laminate having the following (hereinafter referred to as a honeycomb laminate), drying, gelling the sol, and fixing silica fine particles to the fiber gap and the surface of the sheet or laminate. is there.

The silica sol used here is a silica sol in which silica fine particles having a large number of silanol groups on the surface and having a particle diameter of about 120 ° or less are mixed in a proportion of 30% or less as a solid content. When gelled by the means, the silica fine particles are aggregated with each other and bonded in a porous manner to form micropores. On the other hand, the diameter of silica particles
Becomes too small and gels during standing, making it unusable.
May be possible. The details will be described later.

The micropores exhibit strong hygroscopicity together with a large number of silanol groups present on the surface of the silica fine particles. When the particle diameter in the silica sol is large, the diameter of the micropores formed while the silica sol is coagulated and bonded becomes large, so that the hygroscopic action is weak and the cohesive bonding force is also weak, so that it is difficult to use as a honeycomb moisture absorber. On the other hand, a small amount of alkali metal ions in the silica sol also contributes to the hygroscopicity, so that a sol mixed with a relatively large amount is used. Hereinafter, embodiments will be described in detail.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention aims to obtain a high-performance moisture-absorbing sheet and a honeycomb element for exchanging moisture by simple means.

[0010]

(Example 1) Five kinds of silica sols shown in Table 1 below are each preferably fired with 0.2 mm thick ceramic fiber paper to reduce the density, and then the solid content of silica is attached to the weight of the ceramic paper. Impregnated so that the amount becomes about 64 wt%, dried at 150 ° C. for 20 minutes, and gelled the silica sol to obtain an adsorption sheet for moisture exchange. FIG. 2 shows the result of measuring the amount of moisture adsorbed on the sheet over time.

[Table 1]

The measuring method is as follows.
After heating for a minute to completely dehumidify, adsorption is started. In the measuring device, as shown in FIG. 1, a plurality of suction sheets AS are placed on the gantry DS at intervals. The blower F is operated and the air with a constant temperature and humidity is sucked into the duct D while being sucked from the constant temperature and humidity chamber CR. The heater box HD is interposed in the duct D, and the temperature of the air in the duct D is raised to a predetermined value by heating and discharged through the suction sheet AS.

A thermometer T, a hygrometer HM, and an anemometer V are attached to the front and back of the suction sheet AS, and each air condition is measured. On the other hand, the gantry DS on which the suction sheet AS is mounted is directly mounted on the electronic balance EB, and measures an increase in weight as the suction sheet AS absorbs moisture. First, the blower F is operated to make the flow velocity in the duct D constant. Next, suction sheet A
In order to completely dehumidify S, the heater box HD is energized and the air is heated to 140 ° C., and this is heated for 30 minutes by the suction sheet AS
And then completely dehumidified.

Next, the heater H is turned off, the temperature of the air in the duct D is lowered, and the rising of the weight increase of the suction sheet AS is measured approximately every 60 seconds from the time when the suction sheet AS starts suction. This is continued for 20 minutes. This value is plotted in FIG. As can be seen from FIG. 2, the smaller the diameter of the silica particles, the higher the moisture absorption rate.

No. No. 1 (40 °), No. 2 (7
Since the silica particles of 0 °) have the highest moisture absorption rate, they can be used as dehumidifying elements and elements for total heat exchange.
The conditions of moisture absorption are as follows: air temperature 20 ° C., relative humidity 70%, wind speed 1 m / sec. It is. The horizontal axis in FIG. 2 indicates the adsorption time (minute), and the vertical axis indicates the amount of moisture adsorbed on the sheet (g / m ² ). As shown in the figure, the curve of the amount of adsorption (g / m ² ) with respect to time of the adsorption sheet AS is N
o. 1, No. 2, No. 3, No. 4, No. It looks like 5. On the other hand, in the method of using the rotary dehumidifier, as shown by an arrow in FIG. 4, moisture absorption and dehumidification are repeated every one rotation (about 6 minutes) of the rotor, and the moisture absorption time is about 4.5 minutes and the dehumidification time is about 1.5. Minutes.

Therefore, the dehumidifying performance is determined by how much moisture is adsorbed during the 4.5 minutes of the moisture absorption time. As shown in FIG. 2, when the diameter of the silica particles is 40 ° to 70 °, the rise of the moisture absorption rate is extremely fast. 2 is 3
Of about 13 g / m ² per minute. 1 is 21g for 3 minutes
/ ^{M 2} to moisture absorption. As the particle diameter increases to 250 ° and 450 °, the adsorption speed decreases.

For example, No. No. ⁴ absorbed 5 g / m ^{2 in} 3 minutes. 5 also absorbs 2.5 g / m ^{2 in} 3 minutes, and therefore cannot be used for a dehumidifier or a total heat exchanger with this moisture absorbing performance. Accordingly, particles having a performance of being used for dehumidification and total heat exchange are most preferably particles having a particle size of about 120 ° or less.

On the other hand, the adsorption element of the total heat exchanger must efficiently and simultaneously exchange sensible heat and latent heat for each rotation, and the rotation speed of the element for total heat exchange usually has the maximum value of the sensible heat exchange efficiency. 8-16r. p. m. Therefore, it is required that the absorption and desorption rates of moisture are extremely high. 2
Is preferably 70 ° or less. As shown in FIG. 2, the adsorption rate of the sheet increases as the diameter of the silica fine particles in the silica sol decreases.

(Example 2) A glass fiber paper having a thickness of 0.2 mm prepared by adding an organic binder, a paper strength agent and the like to glass fibers is prepared. The silica sol no. Fig. 2 Diaion S of Mitsubishi Kasei Co., Ltd.
The above-mentioned paper is impregnated with a dispersion in which K 1B Na type (hereinafter referred to as SK1B) fine particles are dispersed as a hygroscopic agent by 20% and dried. Affix to obtain a moisture exchange sheet.

The SK 1B has a sodium sulfonate group (—SO ₃ Na) as an ionizing group chemically bonded to the benzene ring of a synthetic resin in which styrene and divinylbenzene are three-dimensionally copolymerized as shown in the chemical formula. It is a strong acid cation exchange resin sodium form (neutral).
Here, the silica fine particles act as a hygroscopic agent, and at the same time, act as a binder for bonding the SK1B fine particles as the hygroscopic agent to the inside and the surface of the sheet, thereby obtaining a hygroscopic sheet having a synergistic hygroscopic action.

Embedded image

(Example 3) A 0.2 mm thick paper obtained by mixing a small amount of pulp and glass fiber with ceramic fiber was formed into a single wave molded body having a pitch of 3.4 mm and a height of 1.8 mm. The honeycomb rotor is obtained by winding and laminating the half-wave forming body on the core material S as shown in FIG. The silica sol no. 2, SK 1B fine particles of Mitsubishi Kasei Co., Ltd. are dispersed in a weight ratio of 20%, and the honeycomb rotor is impregnated with the dispersion and dried to obtain a honeycomb dehumidifying rotor RO. No. 2 Silica gel and SK
The content of 1B fine particles is 2 parts each with respect to the weight of the dehumidifying rotor.
0%. The performance of this rotor RO is inferior to the performance of a rotor using silica sol and zeolite,
It is superior to the performance of the rotor using iCl and can be sufficiently used as a honeycomb dehumidifier.

Honeycomb dehumidifying rotors RD ₁ , RD ₂ , RD
When each of L and RO is used separately, the rotors RD ₁ , RD ₂ , RDL and RO are connected to the casing 11 as shown in FIG.
The rotor is separated into a dehumidifying zone 18 and a regeneration zone 19 by a separator 17, and the rotor is driven by a geared motor 20, a pulley 21, a tension pulley 22, and a driving belt 23 for 10 to 25 rpm. p. h. Rotate with
The processing air TA to be dehumidified is 1 to 3 m / sec. Through the dehumidifying zone 18 to obtain dehumidified air DA, and the regenerating air HA is similarly passed through the regenerating zone 19 from the opposite direction at 1 to 3 m / sec.
And desorbing and regenerating the regenerated portion with hot air at 80 to 150 ° C. In the drawing, reference numeral 24 denotes a seal, and reference numeral 25 denotes a regeneration air heater.

[0022]

According to the present invention, there are provided silica fine particles having a large number of stable silanol groups on the surface, having a particle diameter of about 120 ° or less and having a strong binding force between the fine particles and a strong binding force with other substances, that is, a strong binder force. The silica sol contained is impregnated or coated on a sheet or a honeycomb laminate and dried and gel-fixed, so that each silica fine particle is strongly bonded to the honeycomb laminate while a large number of silica fine particles are bonded to each other to achieve a thickness of 3.0 °-. An enormous number of micropores having a pore diameter of 48 ° are formed and fixed inside and on the surface of the sheet.

In the present invention, the silica fine particles contained in the silica sol having a solid content of 30% or less have a diameter of 120 ° or less, have a stable silanol group, and have a silica sol content of 0.1%.
A sheet or honeycomb laminate is impregnated or coated with a silica sol containing 1 to 1.0 wt% of alkali metal Na ₂ O, and then dried and gelled and fixed to the sol in the sheet or honeycomb laminate. (See FIGS. 5 and 6), a large number of silica fine particles are bonded to each other to form a huge number of micropores having a diameter of 3Å-48Å while being bonded to each other, and to be bonded into the material of the sheet or the honeycomb laminate. In this case, both a silanol group and Na ₂ O are fixed on the surface of the micropore, and exhibit strong water molecule adsorption performance together with the micropore. The smaller the solid content in the silica sol, that is, the smaller the diameter of the silica particles, the stronger the attraction force between the particles and the greater the amount of the silica particles dispersed in the silica sol, the faster the gelation. Gels become unstable in this short time
This will be described later.

For example, Table 1, No. 2, when the content in the silica sol becomes 30% or more, gelation occurs in a short time. In the case where the particle size is 1 and the particle diameter is 40 °, if the content exceeds 15%, it becomes unstable and gels during standing, making it unusable.

In the silica gel obtained from the silica sol used in the present invention, the smaller the silica fine particles in the silica sol, the stronger the hygroscopic power and the stronger the binder power. The silica sol is mixed with organic polymer electrolyte fine particles, etc. If impregnated and fixed, a strong adsorbent can be obtained because the adsorbent and silica gel itself simultaneously act as an adsorbent while acting as a strong binder.

[Brief description of the drawings]

FIG. 1 is an explanatory view of an apparatus for measuring a moisture adsorption amount of a moisture exchange adsorption sheet over time.

FIG. 2 is a graph showing the amount of moisture adsorbed over time of the moisture exchange adsorption sheet of the present invention.

FIG. 3 is a perspective view of a honeycomb rotor for dehumidification.

FIG. 4 is a partially cutaway perspective view of the dehumidifier.

FIG. 5 is an explanatory diagram showing a situation where silica fine particles in a silica sol are mutually bonded.

FIG. 6 is an explanatory diagram showing a situation in which silica fine particles in a silica sol are bonded to each other.

[Explanation of symbols]

 11 casing 17 separator 18 dehumidification zone 19 regeneration zone

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-5-23529 (JP, A) JP-A-6-323 (JP, A) JP-A-7-204451 (JP, A) JP-A-5-205 115737 (JP, A) JP 46-28522 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) B01D 53/28, 53/26 B01J 20/00-20/34

Claims (1)

(57) [Claims] 1. A moisture exchange adsorbent obtained by impregnating or applying hydrophilic organic polymer electrolyte fine particles to a sheet or a laminate having a large number of small pores with a binder having a hygroscopic property, followed by drying and fixing.