JPS6262164A - Adsorption type heat pump - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention has an apparent density of 0.1 to 0.8 jl/crr.
t'', porosity 50-90%, average diameter 1-500 μm
This invention relates to an adsorption pump with a cooling mode and a heating mode, which is formed by connecting an adsorption tower filled with network-structured activated carbon having macropores as an adsorbent, and an evaporator and a condenser containing a working medium. cooling.

Low-temperature fields such as refrigeration and cooling, or hot water supply and space heating.

It can be widely applied to the effective use of energy in high-temperature fields such as heating and finger heating.

(Prior art and its problems) Chemical heat pumps that use solid @adhesive @bottom
Heat pumps using various adsorbents such as silica gel, activated alumina, zeolite, and activated carbon are being considered because they have the advantage of not requiring a power source such as a compressor and can use relatively low-temperature thermal energy as driving energy. ing.

The adsorption properties of these adsorbents are determined by their combination with various working media, and their suitability as adsorbents for heat pumps is evaluated. Activated alumina has the same drawbacks as zeolite, in that it is difficult to desorb and requires a high regeneration temperature with a large difference in regeneration temperature.

In addition, the silica gel-water system can be regenerated by a relatively low heat source of 100° C. or less, but has the disadvantage that it cannot maintain a large difference in the amount of adsorption and desorption.

By the way, when conventional activated carbon uses water as a working medium,
When the relative pressure P/Ps (P: partial pressure of water vapor, Ps: saturated vapor pressure of water) is around 0.6 to 0.6, the adsorption n1 changes significantly, and the operating pressure is adjusted across the area where this adsorption has a large change. It has been found that by providing it on both sides, adsorption and desorption can be carried out easily and the difference in 1nD1 between adsorption and desorption can be made large. However, on the other hand, it has a serious drawback in that the operating pressure is as high as a relative pressure of around 0.6 to 0.6, so the difference in pumping temperature becomes small, which is a major obstacle in its use.

In addition, since the various solid adsorbents mentioned above are usually used in powder or granular form, the pressure loss is large, the movement of the adsorbed substance is not rapid, and the distribution of adsorption cans within the adsorption tower is likely to be uneven. In addition, uneven filling of the adsorbent within the adsorption tower causes non-uniformity in the temperature ε and variations in the heat transfer rate depending on the location within the adsorption tower, which is undesirable.

X: Start... Town; 0: Eye White Thick Sprout 4 Existing 1 sentence →: The present inventor has developed the present invention as a result of research in order to improve the above-mentioned drawbacks of conventional @-type heat pumps. An adsorption tower filled with network-structured activated carbon having macropores of ~90 F% and an average diameter of 1 to 600 μm as an adsorbent, an evaporator containing a working medium, and an evaporator containing a working medium. 5! This is a suction type heat pump with a cooling mode and a heating mode, which is connected to a compressor.

The network activated carbon of the present invention has the following superior features compared to conventional powder activated carbon or granular activated carbon.

That is, compared to granular activated carbon, the rate of adsorption and desorption is extremely high, and adsorption and desorption can be completed in a short time. Since the filling state of the adsorbent in the packed column is uniform and the air permeability is good, there is little variation in the adsorption Q distribution within the packed column, which reduces unevenness in the temperature distribution, making it easy to extract the absorption heat. It is suitable for quickly raising and lowering the temperature of the sorption tower.

In addition, by selecting the activation method, the network activated carbon of the present invention has very fine pores with a maximum value of the distribution of micropore radii (rl) of r<8A or less, and has a specific surface ff Active snoring can be about 500 to 1000 m2#.

The micropores of the present invention have a pore radius r≦20/.

A macropore is a pore with a pore radius r)1
I received information about the 00A pore.

Now, the synthetic resin composite porous body which is a precursor for manufacturing the network activated carbon used in Hon Ugomei's locking type heat pump is known, for example, from Japanese Patent Publication No. 58-54082 and Japanese Patent Application Laid-Open No. 57-57.
It can be produced by the method disclosed in No. 51109, JP-A-57-118009, etc., or other known methods, in which polyvinyl alcohol resin and phenol resin or melamine resin are reacted together with a pore-forming material. After the pore-forming material is removed, the above synthetic resin composite porous material is activated under limited activation conditions, so that the maximum value of the distribution of pore radius 1rl is T.
It becomes UBA, and can be made into a network-structured activated carbon with a large water absorption capacity of 50f using a chain acid with a low relative pressure.

The above-mentioned limited activation conditions are activation at a temperature of about 700° C. or lower in an oxidizing atmosphere such as a steam atmosphere or an air atmosphere. For example, an activation temperature range of about 500 to 700°C is appropriate in a steam atmosphere, and an activation temperature of about 260 to 500°C in an air atmosphere. If the activation temperature is too high, the pore radius of the activated carbon becomes too large, and the amount of water adsorption in the region of low relative pressure decreases significantly, which is not preferable.

Normally, the pore volume and pore size distribution of activated carbon and silica gel adsorbents with fine pores are @ elementary gas.

It is determined from the @deposition isotherm of ethane gas, butane gas, etc. Most commonly, nitrogen gas is used as the adsorbent gas and helium gas is used as the carrier gas, and the relationship between the amount of nitrogen gas adsorbed into the pores of the adsorbent and the nitrogen partial pressure is determined by cooling the adsorbent to liquid nitrogen temperature. gives the adsorption isotherm.

As a method for determining pore volume and pore radius from adsorption isotherms, the Kelvin equation has been proposed based on capillary condensation, and analysis based on this equation is generally performed.

P, the saturated vapor pressure PO when the adsorbed gas condenses into the pores? Saturated vapor pressure of the adsorbed gas under normal conditions 19 Surface tension ■, 1 molecule volume of liquid nitrogen, gas constant T, absolute temperature "T - + Kelvin radius of pore For Kelvin radius of pore, other than capillary condensation For example, Higuchi's method of correcting only the monomolecular layer adsorption amount, or a correction method using the Halsey equation, etc., are often used.

Based on methods other than capillary condensation (Strictly speaking, the applicable range of the Kelvin formula is said to be from 20A to 800A, but a strict pore radius 1111J standard method to replace the Kelvin formula has not yet been established. Even in the region with a radius of 2OA or less, analysis using the Kelvin equation is often used.In the analysis of the pore radius and pore size distribution in the present invention, the Kelvin equation is applied to the commonly used analysis. This is applied in conjunction with the existing correction method.

Now, the results of adsorption isotherms for water of commercially available granular activated carbon and the network activated carbon of the present invention are shown in Figure @1. Although FIG. 1 shows the measurement results at 20°C, almost the same adsorption isotherm was obtained in measurements at 50°C and 70°C.

Conventionally, activated carbon is a non-polar substance unlike silica gel or zeolite, so it has been used under low relative pressure (P) as shown in Figure 1A.
/Pg'::, 0.5 or less), it is known that the amount of water adsorption is extremely small. However, by conceptually examining the composition and activation conditions of distressed activated carbon, the present inventors found that the maximum value of the distribution of pore radius (rl) is r<8A, and as shown in Figure 1B, moisture content under low relative pressure. We have discovered activated carbon that has a large adsorption capacity and is extremely suitable as an adhesive for heat pumps.

In addition to water, the working media for adsorption heat pumps include methanol, ethanol, butanol, and cyclohexano.
, benzyl alcohol A/and other alcohols/vse ammonia, acetone or benzene.

Aromatic hydrocarbons such as toluene and xylene can be used. Among these working media, water has the largest latent heat of evaporation at approximately IQ Keal/moj',
It is most preferred as a working medium in the temperature range of 00°C. 0
In the low temperature range below 100°C, lower alcohols such as methanol-1 ethanol are used as the working medium, and in the high temperature range above 100°C, high boiling point hydrocarbons such as cyclohexanol M, benzyl alcohol, and xylene are used as the working medium. suitable.

Adsorption heat pumps have relatively low temperatures of 60 to 100
It has the advantage of being able to utilize a low-temperature heat source at 100°F (°C), and to simultaneously regenerate the adsorbent and store heat using solar heat. Water is the most suitable working medium for a heat pump that takes advantage of these features. be. Therefore, in the following embodiment, a case will be described in which water is made into a UJa+^ body.

(Effects of the Invention) Figure 2 (1) shows a schematic diagram of a bottom-mounted heat pump in cooling mode and temperature rising mode using the network activated carbon of the present invention.
Shown in (2).

In the case of the cooling mode shown in the second factor (1), first, an evaporator and an adsorption tower are connected, and the working analyte is evaporated from the evaporator and adsorbed by the adsorbent until a predetermined adsorption amount is reached. At this time, the temperature of the evaporator decreases due to the evaporation of the working medium, and the water at the environmental temperature of 1"a can be lowered to Tcold through the heat exchanger. When the adsorption amount of the working medium reaches a predetermined value, switch the valve, The adsorption tower and condenser are connected, and hot water with a heat source temperature T8 is flowed through the adsorption tower to raise the temperature, and the working medium is desorbed and condensed in the condenser. When &N is completed, switch the valve and return to the first adsorption process again. .

@2 In the case of the temperature increase mode shown in Figure (2), first, the evaporator and adsorption tower are connected, and both are heated to a heat source temperature Ts ii,
, 1. l! The working medium is adsorbed on the adsorbent while flowing the water, and the temperature rise in the adsorption tower due to the heat of adsorption is removed by heat exchange, and the temperature of the hot water is raised by Thot from the temperature Ts to heat #j, which can be filtered. The amount of N absorbed in the adsorption tower reaches the specified amount]
, 1 (1, . . .) The working medium is desorbed from the adsorbent and condensed in the condenser at temperature Ta by switching the valve. After the desorption is complete, switch /<fi·B and return to the adsorption process again.

Minoh, Figure 8 shows how water is produced using the adsorption heat pump of the present invention! 1
Ki,・l la! The relative pressure P/p, which represents the relationship between the working medium and the adsorbent when used as a
, water fish mood; to, kg g 1 water saturated vapor pressure) 1 temperature diagram is shown.

・'f,', ,)'d HL (1, ρ), which uses water as a working medium, is made of network-structured activated carbon, and from the @ arrival etc. crosstalk in Figure 1B, the operating pressure is called PA'. c K Pressure (detachable side)
and relative pressure P/P, =0.05・0.25. The high pressure side (adsorption side) has a fluctuation of about 0.25 to 0.50', '%), and preferably the low pressure side (desorption side) °C relative r'
t P/P8 = 0.05 to 0.20, and the relative pressure T'7.1)s can be set to about 0.05 to 0.40 on the high pressure side.

e11+ ,: Place r,, When cooling water at 2o℃, the high pressure side (gney ii I+'°: ) Te c7) It vs. E
If EwoP/P8 = 0.80, then from the equilibrium relationship between the 0 and 0 points of S8, if we ignore the loss due to heat exchange, it is theoretically possible to lower the temperature to 2°C, and ? @The width is 18
℃. However, in the case of conventional activated carbon, it exhibits crosstalk such as @ arrival as shown in Figure IA, so it is necessary to have a wide range of operating pressures.

For example, if the relative pressure on the high pressure side (adsorption side) is P/Ps-(L
When set to 60, the theoretically achievable temperature is 12 degrees Celsius based on the equilibrium relationship between 0 points and 0 points in Figure 8, and the cooling temperature range is 8 degrees Celsius.
It can be seen that the cooling effect of the heat pump of the present invention is large in [ ]. Similarly, in the temperature increasing mode Sr, the operating pressure on the adsorption side is set to P/p using the network activated carbon of the present invention.
! = OJ If we set this, the theoretically possible pumping temperature is 28°C (Fig. It is now possible to raise the temperature, and the operating pressure can be reduced to P on the adsorption side using conventional activated carbon.
12℃ when /P8=0.60 (Fig. 3 ■~@
) is significantly larger than that of

Network structure activated carbon of the present invention, adsorption formula 1 using carbon as an adsorbent 2 to 1
：-、、）Bo;・P is 2. Like the upper series r+, it is possible to increase the cooling width by 1 width and the heating temperature by 1'T, and the energy efficiency can be increased by 3. can.

The network activated carbon of the present invention has an extremely fast adsorption/desorption rate, and can complete adsorption/desorption in a short period of time.

5. The packing condition in the filling tower is uniform and has good air permeability (・
) is good, there is little variation in the distribution of adsorbed residue in the packed column, %par temperature unevenness is less likely to occur, and the absorption of heat of adsorption is improved.
It should be possible to quickly raise and lower the temperature of the F... and g1゛1 towers.

ii In the adsorption heat pump of the present invention, the regeneration temperature of the network-structured activated carbon, which is the absorption agent, can be carried out at a relatively low temperature level of 60 to 90°C, so it can be regenerated using solar thermal energy. If you are going on a business trip, in that case, it is possible to use the network activated carbon as a light and heat material and use the stored heat for a refrigerator or hot water supply system.

Hereinafter, this will be explained in detail using examples.

1 μl I [Example 1 Tonai! fi700. Polyvinyl alcohol with saponification degree of 88%
1. After dissolving 5 kg of 1.5 kg in hot water, 8.2 kg of potato starch was added and heated to gelatinize. This solution has a solid content depth of 6
0% by weight water-soluble resol resin (Showa Kobunshi ■ product, B
(T, -2854) After adding 17 ounces and stirring thoroughly,
Furthermore, 9 kg of 87% formalin and 8.5 KII of 80 Tl 1% oxalic acid were added and mixed uniformly, and water was added to adjust the liquid volume to bring the total liquid volume to 1ooI! And so.

This mixed solution was poured into a mold having an inner diameter of 120 φ and 700 mm L, reacted at 60° C. for 24 hours, and then washed to obtain a PV Yatsunin/phenol synthetic resin composite porous body.

The synthetic resin composite porous body was placed in an electric furnace and heated at 80'C/hr.
The temperature rises to 650 degrees Celsius due to rapid flooding of
After time activation, network activated carbon was obtained.

The network activated carbon has an apparent density ρ=0.21 i/
cm8, porosity 87%, average diameter of macropores 100
The maximum value of the distribution of the linear hole radius 1rl of micropores in μm is r<
There were 8 people.

The measurement results of crosstalk such as water adsorption at 20'C by the network activated carbon are shown in Figure 1B. The adsorption isotherms at 50'C and 70°C are also 20°C when the horizontal axis is organized by the relative pressure P/Ps.
It became almost the same as in the case of .

Using the above network activated carbon, an experiment was conducted to obtain cold heat using a heat pump shown in FIG.

The operating conditions for the experiment were that the amount of moisture adsorbed by the network activated carbon in the adsorption tower was 0.05j1/7 during desorption and 0.2 during adsorption.
0ji/! / was set. The corresponding operating pressure range is relative pressure P/P = 0.12-0.80.

Further, the temperature of water used for cooling is 'ra=g2o°C.

First, water at 20° C. was poured into the evaporator, a valve was opened, and the water evaporated from the evaporator was adsorbed by the network activated carbon in the adsorption tower. This operation lowered the water temperature from 20°C to 6°C.

From the equilibrium relationship shown in Figure 4, the temperature range is 18
It is possible to lower the temperature by 14°C, but in this experiment, it was lowered to 14°C due to heat transfer loss. After adsorption for 40 minutes, the valve was changed to connect the adsorption tower and the condenser, and hot water was flowed into the adsorption tower to desorb water from the adsorbent and condense it into the condenser.

The temperature Tsl of the hot water required for desorption is 59°C based on the equilibrium relationship shown in Figure 4, but in this experiment, taking heat transfer loss into consideration, the temperature Tsl of the hot water is 65°C.
Desorption was carried out for 40 minutes by running warm water at ℃.

From the results of this example, water at 20° C. could be cooled to 6° C. by using activated carbon having a network structure exhibiting crosstalk such as adsorption of water as shown in FIG. 1B.

[Comparative example]

Commercially available granular activated carbon (particle size 10-32 mesh, specific surface area 1,080 m24, packed density 0.45 g/c>
The water adsorption isotherm of a) was as shown in Figure 1.

Using this granular activated carbon, an experiment was conducted to obtain cold water using a heat pump in the same manner as in Example 1. Adsorption 1 was 0.06&/i when attached to the same sphere as Example 1, and 0.201/i when adsorbed.
It was set to l. The corresponding operating pressure range is P/Ps
= 0.42 to 0.61.

The equilibrium relationship of adsorption and desorption operations using this commercially available granular activated carbon is @5
As shown in the figure. As shown in Figure 9g5, the JCR theoretically lowering temperature range is 7.5°C, and it is possible to lower 20°C hot water to 12.6°C, but in reality it was only possible to lower it to 16°C. The adsorption operation was carried out for 40 minutes, and then the adsorption tower and condenser were connected, and desorption was carried out with warm water at 65° C. for 20 minutes.

From these results, it was found that by using the network activated carbon of the present invention, the temperature range of cooling can be widened.

Example 2 Using the same network structure activated carbon as in Example 1, a temperature raising experiment using a heat pump was conducted. The evaporator and adsorption tower were heated with hot water having a heat source temperature (Ta2) of 62° C., and the water evaporated from the evaporator was adsorbed onto the network activated carbon.

The operating conditions are the same as in Example 1, adsorption amount 0.05 CP/P.
a=0.12) ~ 0.20 jl/11 (P/Ps
= 0.80).

The adsorption equilibrium relationship under the conditions of this example is shown in FIG.

The heat source temperature of 62°C can theoretically be raised by 28°C to 90°C, but in this example, it is possible to raise the temperature from 62°C to 75°C by 18°C in an adsorption time of 40 minutes. Ta.

Desorption was carried out for 40 minutes by connecting the adsorption tower and the condenser and passing water at 18° C. through the condenser.

[Comparative Example 2] In the same manner as in Example 2, a temperature raising experiment using a heat pump was conducted using the commercially available granular activated carbon used in Comparative Example 1. The operating range of the heat pump is the adsorption amount 0.05 (P/Ps = 0.42) to 0.2 as in Comparative Example 1.
0 (P/Pg-0.61), and the heat source temperature was 62°C.

From the equilibrium relationship shown in Figure 5, the temperature that can theoretically be reached in a heat pump using commercially available granular activated carbon as an adsorbent is 71.
The temperature range within which the temperature can be raised is as small as 9.5°C. In this experiment, adsorption was carried out for 40 minutes, and the temperature of the actually obtained hot water was 66°C.

For decoupling, the adsorption tower and condenser are connected, and the temperature is set at 18℃ in the kGii vessel.
of water for 20 minutes.

[Brief explanation of the drawing]

Figure 1 shows adsorption crosstalk M% of commercially available granular activated carbon and network activated carbon according to the present invention for water; Figure 2 shows adsorption heat pumps in cooling mode and temperature rising mode using network activated carbon according to the present invention U schematic diagram, Figure 8 shows the relative pressure (P/Ps
4 shows an equilibrium relationship diagram of a reticulated activated carbon-water heat pump according to the present invention, and FIG. 5 shows an equilibrium relationship diagram of a commercially available granular activated carbon-aqueous heat pump. Start / 1 person Kanebo Co., Ltd. °...' 3rd figure activity rawhide - permanent heatbonf'f)''+ffi related 4th
figure

Claims (2)

[Claims] (1) An adsorption tower filled with network activated carbon as an adsorbent, which has an apparent density of 0.1 to 0.8 g/cm^3, a porosity of 50 to 90%, and macropores with an average diameter of 1 to 500 μm, and a working medium. Adsorption heat pump with cooling mode and heating mode, consisting of a connected evaporator and condenser. (2) The network structure activated carbon has a maximum value of the distribution of the pore radius (r) of the micropores such that r<8A.
(3) The adsorption heat pump according to claim 1 or 2, wherein the working medium is water.