JPS6319216B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an adsorbent molded article by molding a pellet-like or bead-like adsorbent using Portland cement as a binder.

The present invention relates to a method for producing a cartridge-type adsorbent, which is formed by adding a binder to a pellet-like or bead-like adsorbent.

One of the fields of use of adsorbents is as a dehumidifier that adsorbs and removes moisture from the air. Dehumidification operations using adsorbents have a long history, and silica gel, alumina gel, etc. have been widely used depending on their performance due to their surface porosity and affinity for water. Synthetic zeolite, introduced by Linde in 1954, has attracted attention as a new type of moisture absorbent due to its water vapor and moisture absorption properties.
Synthetic zeolites used as moisture absorbers are mainly A-type zeolites, and the pore diameters differ depending on the substituent cation; NaA is approximately 4 Å, KA is approximately 3 Å,
CaA has a pore diameter of about 5 Å. Synthetic zeolite Ru. Zeolite X also has substitution types, NaX (13X) and CaX (10X).

These adsorbents are originally in powder form, and are molded using an inert material as a binder in order to be filled into an adsorption tower as a moisture absorbent, and are often used in the form of pellets or beads.

The single-column dehumidifier shown in Figure 1 is used for pressurized air sources such as air brakes of vehicles, instrumentation air sources, and spray guns.The adsorbent used is alumina gel, molecular sheep, etc. is filled in the inner adsorption layer 2. The humid air from the compressor 1 passes through the adsorption layer 2, is dehumidified, and is sent to the source air reservoir 4 as dry air, and a portion is sent to the regenerated air reservoir 3.
each will be sent. When the pressure detected by the pressure gauge 12 approaches the upper limit of the set value (6 to 8 kg/cm ² ), the compressor 1 is stopped by a signal from the pressure regulator 13. At the same time, pressure regulator 13
The pressurized air inside the device is pumped out by the signal from the exhaust device 1.
0 and is exposed to the atmosphere, and dry air flowing back from the regeneration air reservoir 3 flows through the adsorption layer 2 to perform regeneration and desorption. When the air in the regeneration air reservoir 3 is completely consumed, the regeneration is completed. When the pressure of the dry air in the source air reservoir 4 decreases due to consumption and reaches the lower limit of the set pressure, the compressor 1 starts operating in response to a signal from the pressure regulator 13. Simultaneously with the start of operation of the compressor 1, the device is sealed, adsorption operation under pressure is started, and dry air is sent to the source air reservoir 4. At this time, a portion of the dry air is filled into the regeneration air reservoir 3. In FIG. 1, 5, 6, 7, and 8 are valves, 9 is an orifice, and 11 is a conduit communicating with a device that uses pressurized dry air.

However, when such a dehumidifying device is used for a vehicle, for example, the adsorption layer vibrates during use, and if it is filled with pellet or bead-shaped adsorbent as described above, the adsorbent will powder. There is a fear. Therefore, most of this type of adsorbent is used in a cartridge type by adding a binder such as cement or clay to a pellet or bead-shaped adsorbent and forming it into, for example, a cylindrical shape and storing it in a special cartridge container.

Using Portland cement as a binder for adsorbent molded products is a simple method, and
Cement as a binder has many advantages, such as being easily available and very inexpensive, but conventional compacts require long curing in order for the cement to harden through hydration and gain strength. There were some drawbacks.

The inventors of the present invention conducted intensive research to find a method for manufacturing an adsorbent molded body that improves the above-mentioned drawbacks, and as a result, they found a method for manufacturing an adsorbent molded body that can quickly develop strength by steam curing. I found out.

That is, the present invention provides a method for producing an adsorbent molded body in which a pellet-like or bead-like adsorbent is molded using Portland cement as a binder.
The pellet-like or bead-like adsorbent is allowed to absorb water to a saturated state, and then Portland cement paste with a flow value of 150 to 280 is mixed, and after filling into a form and forming, it is heated at a temperature of 50 to 100°C for a certain period of time. This paper proposes a method for producing an adsorbent molded body, which is formed by curing in an atmosphere with a humidity of 90% or higher so that the product of 285 degrees/hour or higher.

Now, when cement paste is mixed as a binder with an adsorbent for dehumidification, the adsorbent adsorbs water in the cement paste, and as a result, the wet state of the mixture fluctuates.

Also, if a dehumidifying adsorbent is left in the atmosphere, it will also adsorb moisture in the atmosphere, so the amount of moisture in the atmosphere will depend on its storage conditions, i.e. the length of time it is left in the atmosphere, and the humidity of the atmosphere. The amount of adsorption is also different, and therefore the amount of water adsorbed from the paste is also different, and the wet state of the mixture is also different. In this way, it is very difficult to control the wetness of the mixture within a certain range. Moreover, heat of adsorption is generated during water adsorption, making it even more difficult to control the wet state of the mixture.

In order to eliminate such difficulties, the present invention allows the adsorbent to absorb moisture in advance to a saturated state. Methods for absorbing moisture include placing it in water, leaving it in a container kept at a constant humidity for a certain period of time, and leaving it in the atmosphere for a long period of time, but the simple and reliable method is to put it in water. After pouring into water, the water is drained by scooping in a mesh basket to obtain an adsorbent that has absorbed moisture to a saturated state (referred to as a wet adsorbent).

Next, Portland cement and water are added to the wet adsorbent and mixed, and this mixture is filled into a mold of a predetermined shape and molded. The appropriate amount of Portland cement to be added is 10 to 30 parts by weight per 100 parts by weight of the wet adsorbent. This was selected based on the strength of the molded body and the pressure loss (referred to as pressure loss) in the ventilated state. The amount of water added is an important factor that influences the moldability and strength of the molded product.

That is, when the moisture content is small, it is difficult to uniformly fill the mixture into the mold during molding, resulting in the formation of sparse and dense portions and poor strength development of the molded product. On the other hand, if the moisture content is high, the cement paste in the mixture will flow and cement will accumulate at the bottom of the compact, resulting in uneven strength of the compact and a significant pressure drop. It gets bigger.

Therefore, it is necessary to specify the amount of water added within an appropriate range, but the fluidity of cement paste varies depending on the particle size distribution of Portland cement, so even if a certain amount of water is added, there will be a difference in fluidity. ,
As a result, the moldability of the mixture is affected. As a result of extensive research into moisture management methods, the present inventors have found that it is effective to specify the flow value of cement at 150 to 280.

The method of defining and measuring the flow value in the present invention is as follows.

The measurement of flow value is based on the cement mortar flow test of JISR5201 (Physical Test Method for Cement), and the flow table, flow cone, and rod should meet the specifications of JISR5201 in terms of shape and dimensions. .

Add a pre-weighed amount of water to the cement, mix well, and then fill two layers of cement paste into a flow cone placed correctly in the center of a flow table that has been thoroughly wiped with a dry cloth.

Poke each layer 15 times across the entire surface so that the tip of the stick penetrates about 1/2 the depth of that layer, and finally fill in the gaps and smooth the surface.

After filling the cement paste into the flow cone in this way, the flow cone is correctly removed upwards, and the cement paste is subjected to a falling motion 15 times in 15 seconds using the method specified in JISR5201, until the cement paste has spread. The flow value is measured in the direction in which the flow diameter is considered to be the maximum and in the direction perpendicular to this direction, and the average value is rounded to an integer value in mm, and the absolute value is taken as the flow value.

The mixture of cement paste and adsorbent prepared in this way is then filled into forms and lightly compacted. After that, with the form attached, it is cured in humid air at room temperature for about 1 day in an atmosphere with a humidity of 90% or more, and then the form is removed, and then the temperature is 50 to 100℃ and the humidity is 90%.
The cement is cured with steam in the above atmosphere to quickly solidify the cement. If the steam curing temperature is high, it will take a short time, and if it is low, it will take a long time, and it is generally expressed as the product of temperature and time. In the experiments conducted by the present inventors, at least 285 degrees/hour, that is, for example, 3 hours at 95 degrees Celsius, is required.
Preferably, a temperature of 900 to 2000 degrees/hour is required. After curing, the molded body is heated at 200 to 350°C in order to remove the moisture retained and adsorbed and to activate it, and is then placed in a special case and fixed to obtain a cartridge-type adsorbent.

The effects of the present invention will be explained below using examples.

Example 1 Zeolite 4A beads with a particle size of 2 mm were immersed in a container containing tap water for 1 hour, and then transferred to a mesh basket to drain the water. 100 parts by weight of this wet adsorbent,
15 parts by weight of ordinary Portland cement was mixed with cement paste to give a flow value of 200 by adding water, and after filling a mold with an inner diameter of 150 mm, it was compressed under a pressure of 8 kg/cm ² to a height of 300 mm. . After leaving the product with the mold attached in a constant temperature and humidity chamber at 20° C. and 95% humidity for one day, the mold was removed and the product was cured at various temperatures and humidity of 90 to 95%. The compressive strength of this thing is
Measurements were made at each hour according to JISA1108, and the results shown in Figure 2 were obtained.

From Figure 2, the compressive strength exceeds 50 kg/cm ² after curing at 95°C for 3 hours, that is, curing at 285°C. The increase in compressive strength becomes gradual after 10 hours at 95℃ (950℃).
degree/hour), 10 hours at 80℃ (800 degrees/hour), 18 hours at 50℃
curing at 95°C for 24 hours (2280°C/hr) or 50°C for 24 hours (1200°C/hr) is sufficient. Therefore, the curing conditions are 285 degrees.
The temperature is preferably 900 degrees/hour to 2000 degrees/hour.

Furthermore, from Fig. 2, it is clear that high strength cannot be obtained at an early stage at temperatures below 40°C. Similarly, the higher the curing temperature, the higher the strength, but the problem is that if the temperature exceeds 100°C, curing will be under pressure.

Example 2 Zeolite 4A beads with a particle size of 2 mm were immersed in a container containing tap water for 1 hour, and then transferred to a mesh basket to drain the water. 100 parts by weight of this wet adsorbent,
Add water to 15 parts by weight of ordinary Portland cement, mix with cement paste to the specified flow value, fill it into a mold with an inner diameter of 150 mm, and compress it under a pressure of 8 kg/cm ² until it reaches a height of 300 mm. did. After leaving this item with the mold attached in a constant temperature and humidity room at 20℃ and 95% humidity for one day, remove the mold and further heat at 60℃ and 95% humidity.
Steam curing was performed for 24 hours under ~95% humidity.

The compressive strength of the molded product after steam curing was measured according to JISA1108. The relationship between flow value and compressive strength is as shown in FIG. In FIG. 3, the horizontal axis shows the flow value and the vertical axis shows the compressive strength.

From Figure 3, the preferred flow value range is 150 to 280.
It is.

Example 3 In the same manner as in Example 1, 100 parts by weight of wet adsorbent and cement paste made by adding water to a predetermined amount of ordinary Portland cement to give a flow value of 200 were mixed and then compressed to form a mixture with a diameter of 150 mm and a height of 300 mm. A cylindrical molded body was obtained, and after curing in humid air for 1 day in the same manner as in Example 2, the mold was removed and steam curing was performed for 24 hours in an atmosphere of 60°C and humidity of 90 to 95%, and the compressive strength was measured according to JISA1108 mentioned above. did. The relationship between the amount of cement added and the compressive strength is shown in Figure 4, and the amount of cement added is preferably 10% or more.

Example 4 A molded article obtained in the same manner as in Example 3 was fired at 350° C. for 1 hour to dehydrate it, and then the ventilation pressure loss of this article was measured. The direction of ventilation was in the vertical direction of the cylinder, and the sides were sealed to prevent gas leakage from the circumferential direction. The gas used is nitrogen and comes from a nitrogen cylinder.
Supplied at a pressure of 6.5Kg/cm ² and a flow rate of 200N/min
And so. Figure 5 shows the relationship between the amount of cement added and pressure loss.

If the amount of cement added exceeds 30% (30 parts by weight of cement per 100 parts by weight of wet adsorbent), the pressure loss will increase, which is not preferable.

Example 5 Zeolite 4A pellets with a diameter of 1.5 mm and a length of 3 mm were soaked in a container of tap water for 1 hour, and then
I transferred it to a mesh basket and drained it. As in Example 1, water was added to 100 parts by weight of this wet adsorbent and 15 parts by weight of ordinary Portland cement to obtain a flow value of 200.
After mixing with cement paste, it was compressed to obtain a cylindrical molded body with a diameter of 150 mm and a height of 300 mm.
After curing in a humid air for 1 day in the same manner as in Example 2, the mold was removed and steam curing was performed for 24 hours at 60°C and a humidity of 90 to 95%.The compressive strength was measured according to JISA1108 and reached 63Kg/ ^cm2. Good results were obtained.

[Brief explanation of the drawing]

Figure 1 is an illustration of a dehumidifying device using a cartridge-type adsorbent, Figure 2 is an explanatory diagram showing the relationship between curing time and compressive strength of an adsorbent molded body, and Figure 3 is an illustration of the flow value and adsorption of cement paste. An explanatory diagram showing the relationship between the compressive strength of the adsorbent molded body, Figure 4 is an explanatory diagram showing the relationship between the amount of cement added and the compressive strength of the adsorbent molded body, and Figure 5 is an explanatory diagram showing the relationship between the amount of cement added and the compressive strength of the adsorbent molded body. FIG. 3 is an explanatory diagram showing the relationship with pressure loss.

Claims (1)

[Claims] 1. In a method for manufacturing an adsorbent molded body, in which adsorbent in the form of pellets or beads is molded using portland cement as a binder, the adsorbent in the form of pellets or beads is made to absorb water to a saturated state, and then the adsorbent is molded with portland cement having a flow value of 150 to 280. After mixing the paste and filling it into a form and compressing it, it is cured in an atmosphere with a humidity of 90% or more so that the product of temperature and time is 285 degrees / hours or more at a temperature of 50 to 100 degrees Celsius. A method for producing an adsorbent molded body.