CN100422662C

CN100422662C - Adsorption heat pump and use of adsorbent as adsorbent for adsoprtion heat pump

Info

Publication number: CN100422662C
Application number: CNB2006101002226A
Authority: CN
Inventors: 垣内博行; 武胁隆彦; 藤井克; 山崎正典; 宅见英昭; 渡边展; 稻垣孝治; 小坂淳; 井上诚司; 井上哲
Original assignee: Mitsubishi Kasei Corp; Denso Corp
Current assignee: Mitsubishi Chemical Corp; Mitsubishi Rayon Co Ltd; Denso Corp
Priority date: 2001-02-21
Filing date: 2002-02-20
Publication date: 2008-10-01
Anticipated expiration: 2022-02-20
Also published as: CN100416182C; CN1880882A; CN100464133C; CN1904512A; CN1869552A

Abstract

A method of application for an adsorption material, including: heating the adsorption materials with adsorbed matter for desorption, cooling the dry adsorption materials to a adsorption temperature for the adsorption, and adsorbing once again, wherein, (1) the adsorptive contains zeolite including aluminum and phosphorous in its skeletal structure, (2) the adsorbent material is an aqueous vapor adsorbing material having a range of which the moisture adsorption amount difference in the adsorbing material found by an expression: the moisture adsorption amount difference is Q2-Q1 (where Q1 is the adsorption amount in relative aqueous vapor pressure phi 1 found based on an aqueous vapor desorption isothermal line measured at a desorption temperature T3 in the adsorption and desorption part, and Q2 is the adsorption amount in relative aqueous vapor pressure phi 2 found based on an aqueous vapor adsorption isothermal line measured at an adsorption temperature T4 in the adsorption and desorption part) is 0.15 g/g or more, in an area where the relative aqueous vapor pressure phi 2 of the adsorption and desorption part in an adsorption operation is within a range from 0.115 up to 0.18, and where the relative aqueous vapor pressure phi 1 of the adsorption and desorption part in an desorption operation is within a range from 0.1 up to 0.14, wherein T0=5-10 DEG C, T1=T3=90 DEG C, T2=T4=40 to 45 DEGC.

Description

Adsorption heat pump and use of adsorbent as adsorbent for adsorption heat pump

Technical Field

The present invention relates to an adsorption heat pump using a specific adsorbent and use of the specific adsorbent as an adsorbent for the adsorption heat pump.

Background

In the adsorption heat pump, in order to regenerate the adsorbent adsorbing the adsorbate, for example, water, the adsorbent is heated to desorb the adsorbate, and the dried adsorbent is cooled to a temperature for adsorption of the adsorbate and reused for adsorption of the adsorbate.

Absorption heat pumps that use waste heat and heat energy at relatively high temperatures (120 ℃ or higher) as a regenerative heat source for an adsorbent have been put to practical use. However, since heat obtained by cooling water of a cogeneration system, a fuel cell, an automobile engine, solar heat, or the like is generally at a relatively low temperature of 100 ℃ or lower, it cannot be used as a driving heat source of an absorption heat pump which has been put to practical use at present, and it is desired to effectively use low-temperature waste heat of 60 to 80 ℃ at 100 ℃ or lower. Among them, the practical use of automobiles generating a large amount of waste heat is also being attempted as much as possible.

Even if the operation principle of the adsorption heat pump is the same, the adsorption characteristics required for the adsorbent greatly differ depending on the available heat source temperature. For example, the waste heat temperature of a gas engine cogeneration process or a solid polymer fuel cell used as a high-temperature side heat source is 60 to 80 ℃, and the cooling water temperature of an automobile engine is 85 to 90 ℃. The temperature of the heat source on the cooling side also differs depending on the installation location of the apparatus. For example, in the case of automobiles, the temperature obtained by a heat exchanger is the temperature of a water cooling tower, river water, and the like in a building, a house, and the like. That is, the operating temperature range of the adsorption heat pump is about 25 to 35 ℃ on the low temperature side and 60 to 80 ℃ on the high temperature side when installed in a building or the like, 30 to 45 ℃ on the low temperature side and 85 to 90 ℃ on the high temperature side when installed in an automobile or the like. In order to effectively utilize waste heat, an apparatus which can be driven even when the temperature difference between the low-temperature side heat source and the high-temperature side heat source is small, and an adsorbent suitable for the apparatus are desired.

As the adsorbent for adsorbing the heat pump, zeolite 13X or silica gel type a is typically known.

Recently, a mesoporous (meso) molecular sieve (FSM-10, etc.) (Japanese patent application laid-open No. 9-178292) synthesized by using a micelle structure of a surfactant as a mold, or a desiccant material collectively called AlPO, has been studied₄Zeolite such as porous aluminophosphate molecular sieve (JP-A-11-197439).

Further, the temperature dependence of the adsorption characteristics of the adsorbent for a heat pump is important, and the description has been made [ chemical engineering treatise, vol.19, No. 6 (1993), p 1165-.

Further, AlPO as a porous aluminophosphate molecular sieve has been introduced₄The dependence of the adsorption Performance on temperature of-5, in particular, shows adsorption performances at 25 ℃ and 30 ℃ [ Colloid PolymSci277(1999) p83-88]. Also introduces AlPO₄-5 temperature dependence, recording adsorption isotherms at 20 ℃, 25 ℃, 30 ℃, 35 ℃, 40 ℃ adsorption process (16 th Zeolite research Association lecture Prep 91; average 12 years, 11 months, 21 days, 22 days).

As the adsorbent for the adsorption heat pump, various kinds of adsorbents have been studied for use, and if we have studied it, there is room for improvement in adsorption performance in order to be applied to an apparatus which can be driven even if the temperature difference between the low temperature side heat source and the high temperature side heat source is small.

Disclosure of Invention

In order to allow the apparatus to operate sufficiently even when the temperature around the adsorbent is relatively high, it is necessary to adsorb the adsorbate at a low relative vapor pressure, and in order to miniaturize the apparatus by designing the amount of the adsorbent to be used so that the amount of adsorption/desorption of the adsorbent becomes large. In addition, in order to use a low-temperature heat source for desorption of the adsorbate (regeneration of the adsorbent), the desorption temperature must be low. That is, as the adsorbent for the adsorption heat pump, (1) an adsorbent that adsorbs an adsorbate at a low relative vapor pressure (adsorbable at high temperature), (2) an adsorbent/desorption amount is large, and (3) an adsorbent that desorbs an adsorbate at a high relative vapor pressure (desorbable at low temperature) are important.

The present invention aims to provide a high-efficiency adsorption heat pump using an adsorbent capable of adsorbing/desorbing an adsorbate in a low relative vapor pressure region.

Further, the present invention provides use of an adsorbent capable of adsorbing/desorbing an adsorbate in a low relative vapor pressure region as an adsorbent for a heat pump.

Further, the present invention provides an adsorption heat pump having practically effective adsorption performance.

That is, the gist of the present invention resides in an adsorption heat pump comprising an adsorbate, an adsorption/desorption unit having an adsorbent for adsorbing/desorbing the adsorbate, an evaporation unit connected to the adsorption/desorption unit to evaporate the adsorbate, and a condensation unit connected to the adsorption/desorption unit to condense the adsorbate, wherein the adsorbent has a relative vapor pressure region in which the amount of water adsorbed changes by 0.18g/g or more when the relative vapor pressure changes by 0.15 on a water vapor adsorption isotherm measured at 25 ℃.

The gist of the present invention resides in the use of the adsorbent as an adsorbent for an adsorption heat pump.

Another gist of the present invention resides in an adsorption heat pump characterized in that: in an adsorption heat pump having an adsorbate, an adsorption/desorption unit having an adsorbent for adsorbing/desorbing the adsorbate, and an evaporation/condensation unit connected to the adsorption/desorption unit for evaporating/condensing the adsorbate, the adsorbent is zeolite having a framework structure containing aluminum, phosphorus, and a heteroatom.

Another gist of the present invention resides in an adsorption heat pump characterized in that: an adsorbing/desorbing part having (a) an adsorbate, (b) an adsorbing material with an adsorbate adsorbed/desorbed, and (c) an evaporating part connected to the adsorbing/desorbing part for evaporating the adsorbateAnd (d) an adsorption heat pump connected to a condensing part of the adsorption/desorption part for condensing the adsorbate, wherein the adsorbent is zeolite containing aluminum, phosphorus and silicon in a framework structure²⁹The integrated intensity area of signal intensities of-108 ppm to-123 ppm on the Si-NMR spectrum is 10% or less of the integrated intensity area of signal intensities of-70 ppm to-123 ppm.

The present inventors have also paid attention to the fact that the operating temperature of the adsorption/desorption unit of the heat pump is different between the time of adsorption and the time of desorption of the adsorbate, and as a result of extensive studies, have obtained the following knowledge: the present invention has been accomplished in view of the fact that a heat pump using an adsorbent having a specific adsorption amount difference within a certain range, which is obtained from (1) an adsorption isotherm at the adsorption/desorption part temperature at the time of adsorption operation and (2) a desorption isotherm at the adsorption/desorption part temperature at the time of desorption operation, has practically useful adsorption performance.

Namely, other points of the present invention are as follows:

an adsorption heat pump characterized by: in an adsorption heat pump having (a) an adsorbate, (b) an adsorption/desorption unit of an adsorbent having an adsorbate adsorbed/desorbed, (c) an evaporation unit connected to the adsorption/desorption unit for evaporation of the adsorbate, and (d) a condensation unit connected to the adsorption/desorption unit for condensation of the adsorbate,

(1) the adsorbent contains at least a zeolite containing aluminum and phosphorus in the framework structure;

(2) the adsorbent is a water vapor adsorbent having a range in which the relative vapor pressure [ phi ] 2b is 0.115 to 0.18 inclusive during the adsorption operation in the adsorption/desorption section and the relative vapor pressure [ phi ] 1b is 0.1 to 0.14 inclusive during the desorption operation in the adsorption/desorption section, and the difference in the adsorption amount of the adsorbent, which is determined by the following equation, is 0.15g/g or more,

differential adsorption Q2-Q1

In this case, the amount of the solvent to be used,

q1 represents the amount of adsorption at φ 1b determined from the vapor desorption isotherm measured at the desorption operating temperature (T3) of the adsorption/desorption unit

Q2 represents the amount of adsorption at φ 2b determined from the vapor adsorption isotherm measured at the adsorption operating temperature (T4) of the adsorption/desorption unit

While

Phi 1b (relative vapor pressure at the time of desorption operation in the adsorption/desorption unit) is the equilibrium vapor pressure of water at the refrigerant temperature (T2) for cooling the condenser/the equilibrium vapor pressure of water at the heat medium temperature (T1) for heating the adsorption/desorption unit

Phi 2b (relative vapor pressure at the time of adsorption operation in the adsorption/desorption unit) which is the equilibrium vapor pressure at the cooling temperature (T0) generated in the evaporation unit/the equilibrium vapor pressure at the refrigerant temperature (T2) cooling the adsorption/desorption unit

(here, let T0 be 5-10 ℃, T1 be T3 be 90 ℃, and T2 be T4 be 40-45 ℃).

Drawings

Fig.1 is a conceptual diagram of an adsorption heat pump.

FIG. 2 is a water vapor adsorption isotherm (25 ℃ C.) of SAPO-34 (manufactured by UOP LLC) in example 1.

FIG. 3 shows SAPO-34 (manufactured by UOP LLC) in example 1²⁹And measuring and recording Si-MAS-NMR spectrum.

Figure 4 is a water vapor adsorption isotherm (25 ℃) of the zeolite of example 2.

FIG. 5 is a drawing showing a structure of example 2²⁹The Si-MAS-NMR spectrum of the zeolite is determined and recorded.

Figure 6 is a water vapor adsorption isotherm (25 ℃) of the zeolite of example 3.

FIG. 7 is a water vapor adsorption isotherm of SAPO-34 (manufactured by UOP LLC) in example 4, showing an adsorption process at 40 ℃ and a desorption process at 90 ℃.

FIG. 8 is a water vapor adsorption isotherm of SAPO-34 (manufactured by UOP LLC) in example 4, showing an adsorption process at 45 ℃ and a desorption process at 90 ℃.

FIG. 9 is a water vapor adsorption isotherm (25 ℃ C.) of the zeolite of the reference example.

FIG. 10 shows a method of preparing a zeolite of reference example²⁹And measuring and recording Si-MAS-NMR spectrum.

FIG. 11 is a water vapor adsorption isotherm (25 ℃ C.) of silica gel form A of comparative example 2.

FIG. 12 is an ALPO-5 water vapor adsorption isotherm (30 ℃ C.) of comparative example 3.

In the figure, reference numeral 1 denotes an adsorption tower, 2 denotes an adsorption tower, 3 denotes an adsorbate pipe, 4 denotes an evaporator, 5 denotes a condenser, 11 denotes a heat medium pipe, 111 denotes a cooling water inlet, 112 denotes a cooling water outlet, 113 denotes a hot water inlet, 114 denotes a hot water outlet, 115 denotes a switching valve, 116 denotes a switching valve, 21 denotes a heat medium pipe, 211 denotes a cooling water inlet, 212 denotes a cooling water outlet, 213 denotes a hot water inlet, 214 denotes a hot water outlet, 215 denotes a switching valve, 216 denotes a switching valve, 30 denotes an adsorbate pipe, 31 denotes a control valve, 32 denotes a control valve, 33 denotes a control valve, 34 denotes a control valve, 300 denotes an indoor unit, 301 denotes a pump, 41 denotes a cold water pipe (inlet), 42 denotes a cold water pipe (outlet), 51 denotes a cooling water pipe (inlet), and 52 denotes a cooling water pipe (outlet).

Detailed Description

The present invention is described in more detail below.

< construction of adsorption Pump >

First, the structure of the adsorption heat pump will be described by taking the adsorption heat pump shown in fig.1 as an example.

The adsorption heat pump mainly comprises the following parts: an adsorbate, an adsorption/desorption unit (adsorption towers 1 and 2, hereinafter, the adsorption/desorption unit may be referred to as an adsorption tower) filled with an adsorbent capable of adsorbing/desorbing the adsorbate and transferring heat generated by adsorption/desorption of the adsorbate to a heat medium, an evaporation unit (evaporator 4) for taking out refrigeration (cold) resulting from evaporation of the adsorbate to the outside, and a condensation unit (condenser 5) for releasing thermal energy resulting from condensation of the adsorbate to the outside.

The evaporator 4 is filled with a refrigerant (water in the present embodiment) in a state in which the inside thereof is substantially kept at a vacuum, and a heat exchanger 43 is provided in the evaporator 4, and the heat exchanger 43 is used for exchanging heat between a heat medium (a fluid in which ethylene glycol antifreeze is mixed in water in the present embodiment) that is subjected to heat exchange with air blown out into the room in the indoor unit 300 and the refrigerant.

The adsorption columns 1 and 2 incorporate heat exchangers having surfaces to which adsorbents are bonded and filled, and the condenser 5 incorporates a heat exchanger 53, and the heat exchanger 53 is used to cool and condense the vapor refrigerant (water vapor) desorbed from the adsorption columns 1 and 2 by a heat medium cooled by outside air or the like.

The adsorption towers 1 and 2 filled with the adsorbent are connected to each other by an adsorbate pipe 30, and control valves 31 to 34 are provided in the adsorbate pipe 30. The adsorbate is present in the adsorbate pipe as an adsorbate vapor, an adsorbate liquid, or a mixture with the vapor.

The evaporator 4 and the condenser 5 are connected to the adsorbate pipe 30. The adsorption towers 1 and 2 are connected in parallel between the evaporator 4 and the condenser 5, and a return pipe 3 for returning an adsorbate (condensed water suitable for regeneration) condensed in the condenser to the evaporator 4 is provided between the condenser 5 and the evaporator 4. Reference numeral 41 denotes an inlet for cold water to be cooled to be output from the evaporator 4, and reference numeral 51 denotes an inlet for cooling water to the condenser 5.

Reference numerals

42 and 52 denote outlets for cold water and cooling water, respectively. Further, the indoor unit 300 for exchanging heat with the indoor space (air-conditioned space) and the pump 301 for circulating cooling water are connected to the cooling

water pipes

41 and 42.

A heating medium pipe 11 is connected to the adsorption tower 1, a heating medium pipe 21 is connected to the adsorption tower 2, and switching

valves

115 and 116, and 215 and 216 are provided to the

heating medium pipes

11 and 21, respectively. The

heating medium pipes

11 and 21 are configured to flow a heating medium serving as a heating source or a cooling source for heating or cooling the adsorbent in the adsorption towers 1 and 2, respectively. The heat medium is not particularly limited, and may be any heat medium that can effectively heat and cool the adsorbent in the adsorption tower.

The hot water is introduced from the inlets 113 and/or 213 by opening and closing the switching valves (3-way valves) 115, 116, 215, and 216, passes through the adsorption towers 1 and/or 2, and is discharged from the outlets 114 and/or 214. The cooling water is also introduced from the inlet 111 and/or 211 by opening and closing the

same switching valves

115, 116, 215, and 216, passes through the adsorbers 1 and/or 2, and is discharged from the outlet 112 and/or 212.

Control valves 31 to 34 for opening and closing the refrigerant pipes are provided in the refrigerant pipe connecting the evaporator 4 and the adsorption towers 1 and 2 and the refrigerant pipe connecting the condenser 5 and the adsorption towers 1 and 2, respectively, and these control valves 31 to 34, a pump 301 for circulating a heating medium, and 3-

way valves

115, 116, 215, and 216 for controlling the flow of the heating medium are controlled by an electronic control device (not shown).

An outdoor unit, a heat source for generating hot water, and a pump (not shown) for circulating a heat medium, which are disposed so as to exchange heat with outside air, are connected to the heat medium pipes 11 and/or 21. The heat source is not particularly limited, and examples thereof include a heat and power cogeneration process such as an automobile engine, a gas engine, or a gas turbine, and a fuel cell, and when used for an automobile, an automobile engine and an automobile fuel cell are preferable heat sources.

< summary of operating principle of adsorption Heat Pump >

Next, an outline of the operation of the air conditioner (adsorption heat pump) according to the present embodiment will be described. By operating the pump 301, the heat medium is circulated between the indoor unit 300 and the evaporator 4, and the liquid refrigerant (suitable water) in the evaporator 4 is evaporated to cool the heat medium and cool the air blown into the room. At the same time, the control valves 31 to 34 and the 3-

way valves

115, 116, 215, and 216 are switched so that one adsorption column of the 2 adsorption columns 1 and 2 performs the adsorption step, and the other adsorption column performs the desorption step (regeneration step).

Specifically, when the adsorption tower 1 is set as the adsorption step and the adsorption tower 2 is set as the desorption step, the control valve 31 is opened and the control valve 33 is closed, and in this state, the 3-way valve 115 is communicated with the cooling water inlet 111 side and the 3-way valve 116 is communicated with the cooling water outlet 112 side, and the control valve 32 is closed and the control valve 34 is opened, and in this state, the 3-way valve 215 is communicated with the hot water inlet 213 side and the 3-way valve 216 is communicated with the hot water outlet 214 side.

In this way, the refrigerant (water vapor) evaporated in the evaporator 4 flows into the adsorbent adsorbed in the 1 st adsorption tower 1, and the temperature of the adsorbent is maintained at a temperature corresponding to the temperature of the outside air by the cooling water from the inlet 111.

On the other hand, in the 2 nd adsorption tower 2, since hot water heated by a heat source (a running engine in the case of a vehicle) is supplied from the hot water inlet 213, the adsorbent in the 2 nd adsorption tower 2 desorbs the refrigerant adsorbed in the adsorption step. And the removed refrigerant (water vapor) is cooled in the condenser 5 and condensed again.

After a predetermined time has elapsed, the adsorption column 1 can be switched to the desorption step and the adsorption column 2 can be switched to the adsorption step by switching the control valves 31 to 34 and the 3-

way valves

115, 116, 215, and 216. By repeating such switching every predetermined time, continuous cooling operation can be performed.

< adsorbent >

One of the features of the present invention resides in an adsorbent material for use in an adsorption heat pump.

< adsorbent-1 >

The adsorbent of the present invention has a relative vapor pressure region in which the amount of water adsorbed changes by 0.18g/g or more, preferably 0.2g/g or more, when the relative vapor pressure changes by 0.15, in the range of 0.05 to 0.30 relative vapor pressure on the water vapor adsorption isotherm measured at 25 ℃. The adsorbent is preferably one in which the change in the amount of water adsorbed is 0.18g/g or more, more preferably 0.2g/g or more, in the range of 0.05 to 0.20.

The adsorbate is adsorbed on the adsorbent as vapor, but the adsorbent is preferably a material whose adsorption amount of the adsorbate greatly changes in a narrow relative vapor pressure range. This is because, if the change in the amount of adsorption of the adsorbate is large in a narrow relative vapor pressure range, the amount of adsorbent required to obtain an equivalent amount of adsorption under the same conditions is reduced, and the adsorption heat pump can be driven even if the temperature difference between the cooling heat source and the heating heat source is small.

The reason why the adsorbent preferably has the above properties will be understood from the following studies.

First, the operating vapor pressure range of the adsorption heat pump is determined by the desorption-side relative vapor pressure (Φ 1a) and the adsorption-side relative vapor pressure (Φ 2a), and Φ 1 and Φ 2 can be calculated using the following equations, and the operable relative vapor pressure range between Φ 1a and Φ 2 a.

Relative vapor pressure on desorption side (φ 1a) equilibrium vapor pressure (Tlow 1)/equilibrium vapor pressure (Thigh)

Adsorption side relative vapor pressure (Φ 2a) equilibrium vapor pressure (Tcoo 1)/equilibrium vapor pressure (Tlow2)

The symbols here have the following meanings:

thigh (high temperature heat source temperature): temperature of heating medium heated when desorbing adsorbate from adsorbent to regenerate adsorbent

Tlow1 (low temperature heat source temperature): temperature of adsorbate in condensation section

Tlow2 (low temperature heat source temperature): temperature of heat medium cooled while the regenerated adsorbent is used for adsorption

Tcoo1 (refrigeration generation temperature): the temperature of the material to be adsorbed in the evaporator, i.e. the temperature of the generated cooling

The equilibrium vapor pressure can be determined from the temperature by using the equilibrium vapor pressure curve of the adsorbate.

Hereinafter, the range of the operating vapor pressure when the adsorbate is water is exemplified. The operating vapor pressure range (phi 1 a-phi 2a) is 0.09-0.29 when the high temperature heat source temperature is 80 ℃ and the low temperature heat source temperature is 30 ℃. Similarly, the operating relative vapor pressure range (phi 1 a-phi 2a) is 0.21-0.29 when the high temperature heat source temperature is 60 ℃ and the low temperature heat source temperature is 30 ℃. Furthermore, if the adsorption heat pump is driven by the waste heat of the automobile engine is estimated according to the description of Japanese patent application laid-open No. 2000-140625, the high temperature heat source temperature is about 90 ℃ and the low temperature heat source temperature is 30 ℃, and the operating relative vapor pressure ranges (φ 1 a- φ 2a) are 0.06-0.29.

Based on the above analysis, it is considered that the operating relative vapor pressure range (φ 1 a- φ 2a) is 0.05-0.30, preferably 0.06-0.29, when the adsorption heat pump is driven by the cogeneration process of the gas engine, the waste heat of the solid polymer fuel cell, or the automobile engine. That is, a material having a large variation in the amount of adsorption in this operating humidity range is good. Therefore, the amount of adsorption is preferably changed greatly in the range of 0.05 to 0.30, preferably 0.06 to 0.29, relative vapor pressure.

For example, a case where a refrigeration capacity of 3.0kw (═ 10,800kJ/hr) is obtained by the adsorption heat pump is assumed. Here, 3.0kw is the cooling capacity of an air conditioner used in a general automobile air conditioner. The capacity of the adsorption heat pump is preferably at least 15 liters or less, which is considered from the examination of the engine room of various vehicles.

Difference in adsorption amount

The adsorbent weight that can be filled in a capacity of 15 liters or less is determined below.

As components to be installed in the engine room, there are an adsorption tower body, an evaporator, a condenser, and control valves. These substantially integrated components must be designed for capacities below 15 liters. According to our investigations, it is believed that the evaporator, condenser and control valves can be formed in a volume of about 4.5 liters. Therefore, the capacity of the adsorption column main body is approximately 10.5 liters or less. Since the packing rate of the adsorbent in the adsorption column and the bulk density of the adsorbent are usually about 30% and 0.6 kg/liter, respectively, the adsorbent can be packed in a weight (W) of about 10.5 × 30% × 0.6 — 1.89 kg.

The required properties of the adsorbent are explained below.

The refrigeration capacity R of the adsorption heat pump is represented by the following formula a.

R＝(W·ΔQ·η_c·ΔH/τ)·η_h... (formula A)

Here, W is the weight of the adsorbent packed in 1 adsorption column (one side); Δ Q is the equilibrium adsorption amount amplitude in the conditions at the time of adsorption and at the time of desorption — the above adsorption amount difference (Q2-Q1); eta_cIs adsorption amplitude efficiency, which represents the proportion of the actual adsorption amplitude in the switching time relative to the equilibrium adsorption quantity amplitude Δ Q; Δ H is the latent heat of evaporation of water; τ is the switching time between the adsorption step and the desorption step; eta_hIs the thermal efficiency, considering the heat loss of the adsorbent or the heat exchanger due to the temperature change between the hot water temperature and the cooling water temperature.

R was 3kw as described above, and W was 1.89kg/2 — 0.95 kg. Further, since τ is approximately 60sec as appropriate according to our past study, Δ H, η_c、η_hSince the values of (b) can be approximately 2500kJ/kg, 0.6 and 0.85, respectively, if Δ Q is obtained from (formula A), Δ Q becomes R/W/η_c/ΔH·τ/η_h＝3.0/0.95/0.6/2500·60/0.85＝0.149kg/kg

That is, the Δ Q of the adsorbent used in the adsorption heat pump for automobile is 0.15g/g or more, preferably 0.18g/g or more, more preferably 0.20g/g or more.

Although the above description is based on the assumption that the present invention is used for automobiles, the present invention can be suitably applied to other applications such as fixing, if the above characteristics are satisfied.

From the above studies, it was confirmed that the adsorbent used in the adsorption heat pump of the present invention was used.

Further, the adsorbent having a difference in the amount of water adsorbed when the relative vapor pressure is changed by 0.15 or more from 0.05 to 0.30 is not particularly limited as long as the characteristic is satisfied, but a promising material is zeolite. Since zeolite is crystalline, the pore volume for adsorption is determined by the framework density. 13X (framework density 12.7T/1000) as an example of zeolite having the smallest framework density

) The maximum adsorption amount of (2) is about 0.30 g/g. Therefore, if the adsorption amount at the lower limit of 0.05 of the relative vapor pressure specified in the present invention is more than 0.15g/g, it is impossible to obtain an adsorption amount difference of 0.18 g/g. Therefore, the amount of adsorption at a relative vapor pressure of 0.05 on the water vapor adsorption isotherm is preferably 0.15g/g or less, more preferably 0.12g/g or less, still more preferably 0.10g/g or less, particularly preferably 0.07g/g or less, and still more preferably 0.05g/g or less.

< adsorbent-2 >

Another feature of the adsorbent material of the present invention is: the vapor adsorbent has a relative vapor pressure (phi 2b) in the range of 0.115 to 0.18 inclusive during the adsorption operation in the adsorption/desorption unit and a relative vapor pressure (phi 1b) in the range of 0.1 to 0.14 inclusive during the desorption operation in the adsorption/desorption unit, and has an adsorption amount difference of the adsorbent, which is determined by the following formula, in the range of 0.15g/g or more.

Differential adsorption Q2-Q1

In this case, the amount of the solvent to be used,

While

(here, let T0 be 5-10 ℃, T1 be T3 be 90 ℃, and T2 be T4 be 40-45 ℃).

The difference in the amount of adsorption of the adsorbent of the present invention is particularly limited by the above formula, but more preferably the adsorbent is one particularly limited by any of the following conditions (a) to (C).

(A) T0 is 10 ℃ and T2 is 40 DEG C

(B) T0 is 5 ℃ and T2 is 40 DEG C

(C) T0 is 10 ℃ and T2 is 45 DEG C

The performance of the adsorbent will be described below with reference to fig. 1.

First, the case of closing the

control valves

31 and 34 and opening the

control valves

32 and 34 will be described with reference to fig. 1.

In this case, the water vapor supplied from the evaporator 4 is adsorbed, and the adsorbent packed in the adsorption tower 2 generates heat. At this time, the adsorption tower 2 is cooled and heated by the heat medium (for example, cooling water) flowing through the heat

medium pipes

211 and 21. The temperature of the heat medium (cooling water) supplied from the pipe 211 to cool the adsorption tower 2 (adsorption/desorption unit) at this time is T2.

On the other hand, the temperature of the evaporator 4 is controlled according to the purpose of generating the refrigeration. At this time, the suction-side relative vapor pressure φ 2b is defined by the following equation.

Adsorption side relative vapor pressure phi 2b is equilibrium vapor pressure (T0)/equilibrium vapor pressure (T2)

Equilibrium water vapor pressure (T0): equilibrium vapor pressure at temperature T0 of evaporator 4

Equilibrium water vapor pressure (T2): equilibrium vapor pressure of heat carrier temperature T2 of adsorption tower 2

Meanwhile, while the adsorption tower 1 is in the desorption (regeneration) process, the adsorbent filled in the adsorption tower 1 is regenerated by the regeneration heat source (temperature at which the heat medium in the adsorption/desorption unit is heated, this temperature is T1). The condenser 5 is cooled by cooling water supplied through the heat transfer pipe 51, and condenses water vapor. At this time, the desorption-side relative vapor pressure φ 1 is defined by the following equation.

Relative vapor pressure on desorption side φ 1b (equilibrium vapor pressure (T2)/equilibrium vapor pressure (T1)

Equilibrium vapor pressure (T2): equilibrium vapor pressure at the temperature of the condenser 5 (equilibrium vapor pressure at the heat medium temperature T2 of the adsorption tower 2)

Equilibrium vapor pressure (T1): equilibrium vapor pressure at regeneration heat source temperature (T1) of adsorption tower 1

It is important here that the temperature at the time of adsorption in the adsorption column is different from the temperature at the time of desorption (regeneration). Therefore, in the present invention, the difference in the amount of adsorption can be obtained from the desorption isotherm at the desorption temperature and the adsorption isotherm at the adsorption temperature, and specifically calculated by the following formula:

differential adsorption Q2-Q1

In this case, the amount of the solvent to be used,

q1 represents the amount of adsorption at φ 1b determined from the vapor desorption isotherm measured at the desorption operating temperature (T3) of the desorption unit

While

Phi 1b (relative vapor pressure at the time of desorption operation in the adsorption/desorption unit) is the equilibrium vapor pressure of water at the refrigerant temperature (T2) for cooling the condenser/the equilibrium vapor pressure at the heat medium temperature (T1) for heating the adsorption/desorption unit

(here, let T0 be 5-10 ℃, T1 be T3 be 90 ℃, and T2 be T4 be 40-45 ℃).

The adsorbent of the present invention has an adsorption amount difference of 0.15g/g or more, preferably 0.18g/g or more, as determined by the above formula. Although the larger the difference in the adsorption amount, the better, it is usually 0.50g/g or less, in reality 0.40g/g or less, and even 0.35g/g or less, from the viewpoint of the available material source satisfying the required properties.

The difference in the amount of adsorption may be, for example, 0.15g/g or more as measured under the conditions of (1) 10 ℃ for T0 and 40 ℃ for T2, (2) 5 ℃ for T0 and 40 ℃ for T2, or (3) 45 ℃ for T0 and 10 ℃ for T2.

The difference in the required adsorption amount is 0.15g/g or more, and if the adsorption heat pump is used for an automobile, it can be derived from the following analysis.

Temperature at adsorption and temperature at desorption

First, as described above, since the adsorption amount depends on the temperature at the time of adsorption and the temperature at the time of desorption, the adsorption isotherm at the temperature at the time of adsorption and the desorption isotherm at the temperature at the time of desorption are obtained.

At the time of adsorption, the adsorption tower is cooled with cooling water in order to suppress heat generation due to adsorption heat, and therefore the cooling water temperature (T2) is approximately the adsorption time temperature (T4). On the other hand, since the adsorption column must release heat during desorption, the hot water temperature (T1) becomes the desorption temperature (T3).

However, the heat medium temperature of the adsorption heat pump is (1) a hot water temperature, which is a temperature obtained by using engine cooling water, and is approximately 90 ℃; (2) the cooling temperature is approximately 40-45 ℃ because the temperature is obtained by heat exchange with the outside air; (3) the temperature of the cold water required for producing the cold air is approximately 5 to 10 ℃. That is, the cold water temperature is approximately 5 to 10 ℃ on the premise of a general vehicle in japan. The cooling temperature is about 40 ℃ in Japan, and is about 45 ℃ in a region where the outside air temperature is high.

Therefore, the adsorption temperature (T4) was approximately 40 ℃ to 45 ℃ and the desorption temperature (T3) was approximately 90 ℃.

The present invention is based on the finding that the difference in adsorption amount obtained from at least one adsorption isotherm of adsorption isotherms obtained at an adsorption temperature of 40 ℃ to 45 ℃ and a desorption isotherm obtained at a desorption temperature of 90 ℃ is 0.15g/g or more, using the required adsorption temperature and desorption temperature as indices for evaluating the performance of an adsorbent.

Difference in adsorption amount

The difference in the adsorption amount (0.15 g/g or more) was determined in the same manner as in the adsorbent-1.

Although the above description is based on the assumption that the present invention is applied to automobiles, the present invention can be suitably applied to other applications such as fixing, if the above characteristics are satisfied.

The difference in the amount of adsorption of the present invention is satisfied in that the relative vapor pressure φ 2b is in the range of 0.15 to 0.18 in the adsorption operation of the adsorption/desorption unit, and the relative vapor pressure φ 1b is in the range of 0.1 to 0.14 in the desorption operation of the adsorption/desorption unit. This range corresponds approximately to the range of relative vapor pressures for operation of the adsorption heat pump.

In the region where φ 1b and φ 2b are in the range of 0.115 to 0.18 inclusive and φ 1b is equal to or larger than φ 2b, when the difference in the adsorption amount is in the range of 0.15g/g or larger, the operation is facilitated even under severe temperature conditions which have been considered to be impossible to start up as an adsorption heat pump.

The adsorbent-2 is selected from zeolites having a framework structure containing at least aluminum and phosphorus.

< Material for adsorbent >

The adsorbent of the present invention is preferably a zeolite, and particularly preferably a zeolite containing aluminum, phosphorus and heteroatoms in the framework structure. The Zeolite referred to herein may be a natural Zeolite or an artificial Zeolite, and for example, if the Zeolite is an artificial Zeolite, it includes aluminosilicates, aluminophosphates, and the like specified by the International Zeolite Association (International Zeolite Association IZA).

Here, ALPO is responsible for the aluminum phosphates₄-5 exhibits hydrophobic adsorption characteristics and is not suitable as an adsorbent material according to the present invention. In order to be suitably used and to have hydrophilicity, it is preferable that a part of aluminum or phosphorus is replaced with a hetero atom such as silicon, lithium, magnesium, titanium, zirconium, vanadium, chromium, manganese, iron, cobalt, nickel, palladium, copper, zinc, gallium, germanium, arsenic, tin, calcium, or boron.

Among them, zeolites obtained by replacing a part of aluminum or phosphorus with silicon, magnesium, titanium, zirconium, iron, cobalt, zinc, gallium, or boron are also preferable, and zeolites replaced with silicon, which is generally referred to as SAPO, are most preferable. In addition, two or more of these substituted hetero atoms may be used.

In the zeolite used as the adsorbent in the present invention, the aluminophosphate is a zeolite containing aluminum, phosphorus and a hetero atom in the framework structure, and preferably has the presence ratio of atoms represented by the following formulae (1), (2) and (3).

0.001≤x≤0.3 ...(1)

(wherein x represents the molar ratio of the hetero atom to the sum of the aluminum, phosphorus and the hetero atom in the skeleton structure.)

0.3≤y≤0.6 ...(2)

(wherein y represents the molar ratio of aluminum to the sum of aluminum, phosphorus and hetero atoms in the skeleton structure.)

0.3≤z≤0.6 ...(3)

(wherein z represents a molar ratio of phosphorus to the sum of aluminum and phosphorus in the skeleton structure and a hetero atom.)

Further, in the above-mentioned atom existing ratio, the hetero atom existing ratio is preferably represented by the following formula (4):

0.003≤x≤0.2 5 ...(4)

(wherein x has the same meaning as defined above)

More preferably, it is represented by the following formula (5).

0.005≤x≤0.2 ...(5)

Even in zeolites containing aluminum, phosphorus and heteroatoms in the framework structure, it is preferred that the heteroatoms be silicon atoms, the zeolites having²⁹The integrated intensity area of the signal intensity of-108 ppm to-123 ppm in the Si-MAS-NMR spectrum is preferably 10% or less, more preferably 9.5% or less, particularly preferably 9% or less, of the integrated intensity area of the signal intensity of-70 ppm to-123 ppm.

And of zeolites²⁹The integrated intensity area of signal intensities of-70 ppm to-92 ppm in the Si-MAS-NMR spectrum is preferably 25% or more, more preferably 50% or more, of the integrated intensity area of signal intensities of-70 ppm to-123 ppm.

In addition, the invention²⁹The Si-MAS-NMR spectrum was measured under the following conditions, in which the test material was stored in a water dryer at room temperature for a whole day and night with tetramethylsilane as a standard substance and the test material saturated and adsorbed with water was saturated and adsorbed.

The device comprises the following steps: chemetic CMX-400

Measuring head: 7.5mmMAS probe

Resonance frequency: 79.445MHz

Pulse amplitude: 5.0 microseconds

Pulse series: single pulse

Waiting time: 60 seconds

Revolution number: 4000rps

Of zeolites²⁹The spectrum of Si-MAS-NMR gives information about the binding state of Si in zeolite, which can be known from the position or distribution of the peaks.

Although the ideal zeolite of the present invention contains aluminum, phosphorus and silicon, the silicon atoms in the zeolite are in the form of SiO₂Is present in units. Herein, in²⁹The peak near-90 ppm in the spectrum of Si-MAS-NMR is a case where a silicon atom is bonded to an atom other than 4 silicon atoms through an oxygen atom. In contrast, the peak around-110 ppm is a case where silicon atoms are bonded to 4 silicon atoms through oxygen atoms. That is, a zeolite having a high peak strength in the vicinity of-110 ppm means that silicon atoms are aggregated, and the dispersibility of silicon atoms in the zeolite is low.

The zeolite exhibiting the above spectrum tends to satisfy the adsorption characteristics of the present invention. This is considered to be because the dispersibility of Si affects the adsorption characteristics of zeolite, and zeolite having high Si dispersibility particularly exerts performance suitable for an adsorbent for an adsorption heat pump as described later.

On the other hand, the zeolite used as the adsorbent in the present invention is preferably one having a framework density (framework) of 10.0T/1,000

Above 16.0T/1,000

Hereinafter, more preferably 10.0T/1,000

Above 15.0T/1,000

Zeolites in the following ranges. Here, the boneShelf Density, means per 1,000The number of elements constituting the framework other than oxygen of the zeolite in (b) is determined by the structure of the zeolite.

Skeletal density is related to pore volume. In general, a large skeleton density tends to result in a small pore volume and an insufficient adsorption amount, and the performance of the adsorbent as an adsorption heat pump tends to deteriorate. On the other hand, if the skeleton density is low, the volume of pores that can be adsorbed becomes large and the amount of adsorption becomes large, but the density of the adsorbent becomes low and the strength tends to deteriorate.

The structure of the zeolite satisfying the above-mentioned framework density is represented by a code determined by IZA, such as AFG, MER, LIO, LOS, PHI, BOG, ERI, OFF, PAU, EAB, AFT, LEV, LTN, AEI, AFR, AFX, GIS, KFI, CHA, GME, THO, MEI, VFI, AFS, LTA, FAU, RHO, DFO, EMT, AFY, BEA, and the like, and preferably AEI, GIS, KFI, CHA, GME, VFI, AFS, LTA, FAU, RHO, EMT, AFY, BEA, and a zeolite having a CHA, AEI, or ERI structure is preferably a structure of CHA.

The structure Of zeolite was determined by measuring XRD characteristic curve by Powder XRD (Powder X-ray diffraction), and comparing it with XRD characteristic curve described in Collection Of modulated XRD Powder Patterns Fof Zeolites (1996, ELSEVIER).

The relationship between the Structure and the skeleton density is described in Atlas Of Zeolite Structure Types (1996, ELSEVIER) Of IZA, and the skeleton density can be known from the Structure.

For example, a silicoaluminophosphate having a CHA structure can have a desired adsorption performance by using a silicoaluminophosphate known as SAPO-34 in which atoms such as silicon are incorporated into the framework structure of zeolite.

In addition, as the adsorbent of the present invention, zeolite containing aluminum, phosphorus and hetero atoms in the framework structure is preferable, but the zeolite may be aluminosilicate so long as it has the above adsorbent characteristics, and in this case, a part of silicon and aluminum (or all of aluminum in the case of aluminum) in the framework is substituted with other atoms, for example, magnesium, titanium, zirconium, vanadium, chromium, manganese, iron, cobalt, zinc, gallium, tin, boron, and the like. In the case of aluminosilicates, if the molar ratio of silicon to aluminum is too small, adsorption occurs rapidly in an excessively low humidity region as in the case of zeolite 13X; when too large, water is not absorbed so much because it is too hydrophobic. Therefore, the zeolite used in the present invention has a silicon/aluminum molar ratio of usually 4 to 20, preferably 4.5 to 18, more preferably 5 to 16.

The zeolite includes a form having a cation species that can be exchanged with another cation, and examples of the cation species in this case include protons, alkali elements such as Li and Na, alkaline earth elements such as Mg and Ca, rare earth elements such as La and Ce, transition metals such as Fe, Co and Ni, and the like, and protons, alkali elements, alkaline earth elements and rare earth elements are preferable. And protons, Li, Na, K, Mg, Ca are more preferable. These zeolites may be used alone, in combination of a plurality of them, or in combination with other silica, alumina, activated carbon, clay, etc.

The pore diameter of the adsorbent of the present invention is preferably 3Above, particularly preferably 3.1

The above. Further, it is preferably 10

Among them, it is also preferable that 8 is used

The content is preferably 7.5

The following. If fine holesIf the diameter is too large, the water molecules may not be adsorbed at the intended relative humidity, and if the diameter is too small, the water molecules as the adsorbate tend to be difficult to diffuse on the adsorbent.

The heat of adsorption of the adsorbent of the present invention is preferably 40kJ/mol or more and 65kJ/mol or less. In addition, the easy desorption is also an important characteristic for the adsorbent of the adsorption heat pump that must be desorbed by a heat source of 100 ℃. The degree of easy desorption is inversely proportional to the adsorption force. Therefore, the heat of adsorption as an index showing the degree of adsorption is desirably close to the latent heat of condensation of water and not less than it, at 40KJ/mol or more. Further, if the heat of adsorption is too large, desorption by a heat source of 100 ℃ or lower tends to be difficult. Therefore, it is preferable to use zeolite which exhibits an adsorption heat of 65kJ/mol or more and 65kJ/mol or less, both inclusive of the latent heat of condensation of water. In the present specification, the differential heat of adsorption was determined by simultaneous measurement of the amount of adsorption and the heat of adsorption (measurement temperature 25 ℃) according to the method described in [ Colloid Polym Sci277(1999) p83-88], and the differential heat of adsorption in the range of the amount of adsorption from 0.005mol/g to 0.01mol/g was used as the heat of adsorption.

An example of a particularly preferable adsorbent used in the present invention is a CHA-type adsorbent (having a framework density of 14.6T/1,000)

) SAPO (silicoaluminophosphate) of (i) SAPO 34.

The zeolite of the present invention is not particularly limited as long as it has the above-mentioned properties, and can be produced by the following method, for example, by referring to the methods described in JP-A-4-37007, JP-A-5-21844, JP-A-5-51533, and U.S. Pat. No. 4440871. A method for synthesizing SAPO-34 is described in U.S. Pat. No. 4440871.

In particular, as a production method for producing the above-described preferable zeolite containing aluminum, phosphorus and silicon in the framework structure, the following methods can be mentioned, for example.

First, an aluminum material, a silica material, a phosphoric acid material, and a template are mixed to prepare an aqueous gel.

As the aluminum raw material, pseudo boehmite, aluminum isopropoxide, aluminum hydroxide, alumina sol, sodium aluminate, or the like can be used.

As the silica raw material, fumed silica, silica sol, colloidal silica, water glass, disilyloorthosilicate, methyl silicate, or the like can be used.

Phosphoric acid can be used as the phosphoric acid raw material. In addition, aluminum phosphate may also be used.

As the template (template), there can be used a 4-stage ammonium salt such as tetramethylammonium, tetraethylammonium, tetrapropylammonium or tetrabutylammonium, morpholine, di-N-propylamine, tripropylamine, triethylamine, triethanolamine, piperidine, cyclopropanamine, 2-methylpyridine, N-dibenzylamine, N-diethylstilanolamine, dicyclohexylamine, N-dimethylethanolamine, choline, N '-dimethylpiperazine, 1, 4-diazabicyclo (2, 2, 2) octane, N-methyldiethanolamine, N-methylethanolamine, N-methylpiperidine, 3-methylpiperidine, N-methylcycloethylamine, 3-methylpyridine, 4-methylpyridine, quinuclidinyl, N' -dimethyl-1, 4-diazabicyclo (2, 2, 2) octane ion, 1-stage amines such as di-n-butylamine, neopentylamine, di-n-pentylamine, isopropylamine, t-butylamine, ethylenediamine, pyrrolidine, 2-imidazolidinone, di-isopropyl-ethylamine, and dimethylcyclohexylamine, 2-stage amines, 3-stage amines, and polyamines.

Although the order of mixing the aluminum raw material, the silica raw material, the phosphoric acid raw material, and the template varies depending on the conditions, generally, the phosphoric acid raw material and the aluminum raw material are mixed first, and the silica raw material and the template are mixed therein. The composition of the aqueous gel is generally 0.02 < SiO, expressed as the molar ratio of the oxides₂/P₂O₅＜20、0.02＜SiO₂/Al₂O₃< 20, preferably 0.04 < SiO₂/P₂O₅＜10、0.04＜SiO₂/Al₂O₃Is less than 10. The pH of the aqueous gel is from 5 to 10, preferably from 6 to 9.

In addition, other components than the above may be appropriately present in the aqueous gel. Examples of such components include hydroxides or salts of alkali metals or alkaline earth metals, and hydrophilic organic solvents such as alcohols.

The prepared aqueous sol is put into a pressure-resistant vessel, pressurized by its own pressure or by a gas which does not inhibit crystallization, and kept at a predetermined temperature while stirring or standing, thereby carrying out hydrothermal synthesis.

The conditions for the hydrothermal synthesis are usually 100 to 300 ℃ and preferably 120 to 250 ℃. The reaction time is usually 5 hours to 30 days, preferably 10 hours to 15 days.

After hydrothermal synthesis, the product is separated, and the organic matter contained in the product is removed by a method such as washing with water, drying, and firing to obtain zeolite.

When zeolite is processed for use as a water vapor adsorbing material, care must be taken not to deteriorate the adsorption performance of zeolite, but generally, it is molded with an inorganic binder such as alumina or silica.

In order to impart a desired water vapor adsorbing performance to the adsorbent, the adsorbent may contain a silica sol, mesoporous silica, alumina, activated carbon, clay, or the like in addition to the zeolite of the present invention. However, in order to obtain good adsorption characteristics at low relative vapor pressures, the proportion of zeolite in the adsorbent of the present invention is usually 60% by weight or more, preferably 70% by weight or more, more preferably 80% by weight or more, and from the viewpoint of adsorption characteristics, only zeolite is preferably used as the water vapor adsorbent.

When the adsorbent is used in an adsorption heat pump or the like, it is processed and used by a known method for designing a predetermined strength, particle diameter and shape for the application. For example, as described in Japanese patent laid-open No. 2001-38188, the adsorbent particles for the adsorption heat pump are preferably about 0.05mm to 2 mm. Further, as described in Japanese patent application laid-open No. 2000-18767, when the adhesive is used for bonding to the absorbent core, the strength must be such that the absorbent particles are not damaged even if the adhesive and the absorbent particles are mixed and dispersed.

< method of operation >

The operation method of the adsorption heat pump will be described with reference to fig. 1. In the 1 st stroke, the

control valves

31 and 34 are closed, the

control valves

32 and 33 are opened, the regeneration stroke is performed in the adsorption column 1, and the adsorption stroke is performed in the adsorption column 2. The switching

valves

115, 116, 215, and 216 are operated to pass hot water through the heating medium pipe 11 and to pass cooling water through the heating medium pipe 21.

For example, when cooling the adsorption tower 2, cooling water cooled by heat exchange with outside air, river water, or the like by a heat exchanger such as a cooling tower is introduced through the heat medium pipe 21 and is cooled to about 30 to 40 ℃. The water in the evaporator 4 is evaporated by opening the control valve 32, and the water vapor flows into the adsorption tower 2 and is adsorbed on the adsorbent. The vapor is moved by the difference between the saturated vapor pressure at the evaporation temperature and the adsorption equilibrium pressure corresponding to the temperature of the adsorbent (generally, 20 to 50 ℃, preferably 20 to 45 ℃, more preferably 30 to 40 ℃), and the evaporator 4 is cooled by the heat of vaporization corresponding to the evaporation, that is, the output of the cooling. Although the adsorption-side relative vapor pressure Φ 2a (where Φ 2a is obtained by dividing the equilibrium vapor pressure of the adsorbate at the temperature of the cooling water in the adsorption tower by the equilibrium vapor pressure of the adsorbate at the temperature of the cooling water generated in the evaporator) is determined from the relationship between the temperature of the cooling water in the adsorption tower and the temperature of the cooling water generated in the evaporator, it is preferable to operate in the case where Φ 2a is greater than the relative vapor pressure at which the adsorbent specified in the present invention adsorbs water vapor to the maximum. If φ 2a is smaller than the relative vapor pressure at which the adsorbent specified in the present invention adsorbs water vapor to the maximum, the adsorption energy of the adsorbent cannot be effectively used, and the operation efficiency is poor. Although φ 2a may be set as appropriate depending on the ambient temperature or the like, the adsorption heat pump is operated under the temperature condition that the adsorption amount at φ 2a is usually 0.20 or more, preferably 0.29 or more, more preferably 0.30 or more. The adsorption amount can be determined from an adsorption isotherm measured at 25 ℃.

The adsorption tower 1 in the regeneration step is heated with hot water of usually 40 to 100 ℃, preferably 50to 98 ℃, more preferably 60 to 95 ℃ to reach an equilibrium vapor pressure corresponding to the above temperature range, and condensed at a saturated vapor pressure at a condensation temperature of 30 to 40 ℃ of the condenser 5 (which is equal to the temperature of the cooling water for cooling the condenser). The water vapor moves from the adsorption tower 1 to the condenser 5, and is condensed into water. The water is returned to the evaporator 4 by the return pipe 3. Although the desorption-side relative vapor pressure Φ 1a (where Φ 1 is obtained by dividing the equilibrium vapor pressure of the adsorbate at the hot water temperature by the equilibrium vapor pressure of the adsorbate at the cooling water temperature of the condenser) is determined according to the relationship between the cooling water temperature and the hot water temperature of the condenser, it is preferable to operate in a case where Φ 1a is smaller than the relative vapor pressure of the adsorbate at which the adsorbent rapidly adsorbs water vapor. Although φ 1a can be set as appropriate depending on the ambient temperature or the like, the adsorption heat pump is operated under the temperature condition that the adsorption amount at φ 1a is usually 0.06 or less, preferably 0.05 or less. The difference between the amount of adsorbate adsorbed at φ 1a and the amount of adsorbate adsorbed at φ 2a is usually 0.18g/g or more, preferably 0.20g/g or more, more preferably 0.25g/g or more. The above is the 1 st stroke.

In the following 2 nd cycle, the adsorption tower 1 is changed to the adsorption step and the adsorption tower 2 is changed to the regeneration step by switching the control valves 31 to 34 and the switching

valves

115, 116, 215, and 216, and the refrigeration, i.e., the refrigeration output, can be obtained from the evaporator 4 in the same manner. The adsorption heat pump is continuously operated by sequentially switching the 1 st and 2 nd strokes.

Although the operation method in which 2 adsorption towers are provided is described here, the adsorption towers may be provided in several cases if the state in which any one adsorption tower can adsorb an adsorbate can be maintained by appropriately desorbing the adsorbate adsorbed by the adsorbent.

In addition, the adsorption heat pump uses the ability of the adsorbent to adsorb/desorb the adsorbate as a drive source. In the adsorption heat pump, water, ethanol, acetone, or the like can be used as the adsorbate that is the adsorbate, but water is most preferable in terms of safety, price, and the magnitude of latent heat of evaporation.

The adsorption heat pump of the present invention uses an adsorbent that can obtain a large change in adsorption amount with a narrow range of relative vapor pressure change, and therefore, is suitable for applications requiring a smaller device and restricting the filling amount of the adsorbent, such as an automotive air conditioner.

Examples

The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples.

In the following examples, the water vapor adsorption isotherm at 25 ℃ was obtained by measuring the water vapor adsorption characteristics of the adsorbent under the following conditions.

Adsorption isotherm measurement apparatus: ベルソ - ブ 18 (manufactured by Nippon ベル Co., Ltd.)

Air high temperature bath temperature: 50 deg.C

Adsorption temperature: 25 deg.C

Initial introduction pressure: 3.0torr

Number of introduced pressure set points: 0

Saturated vapor pressure: 23.76mmHg

The balance time is as follows: 500 seconds

Pretreatment: vacuum sucking at 300 deg.C for 5 hr

The differential heat of adsorption was measured under the following conditions.

A measuring device: calorimeter and measuring apparatus for adsorption amount (Tokyo manufacturing)

Temperature of the measuring part: 25 deg.C

Temperature of the thermostatic bath for steam introduction: 30 deg.C

Example 1

A water vapor adsorption isotherm (25 ℃ C.) of SAPO-34 (manufactured by UOP LLC) is shown in FIG. 2. As is clear from FIG. 2, when water vapor is rapidly adsorbed at a relative vapor pressure of 0.07 to 0.10, the amount of change in the amount of adsorption is 0.25g/g, with a relative vapor pressure of 0.05 to 0.20.

Additionally, SAPO-34 is a CHA-type silicoaluminophosphate having a CHA-type framework density of 14.6T/1,000

Pore diameter of 3.8

And obtained by using SAPO-34 (manufactured by UOP LLC)²⁹The Si-MAS-NMR record is shown in FIG. 3. According to the spectral measurement record, on the spectrum, the integrated intensity area of the signal intensity of-70 ppm to-123 ppm, the integrated intensity area of the signal intensity of-108 ppm to-123 ppm is 0.6%, and the integrated intensity area of the signal intensity of-70 ppm to-92 ppm is 85.9%. When the heat of adsorption was determined, it was 58.6 kJ/mol.

Example 2

The CHA-type silicoaluminophosphate is produced by the following method with reference to the method described in Japanese patent application laid-open No. 4-37007.

15.4g of 85% phosphoric acid and 9.2g of pseudoboehmite (25% water, manufactured by コンデア) were slowly added to 18g of water, and stirred. Then, 10g of water was added thereto and stirred for 1 hour to obtain a liquid A. Separately from the liquid A, a liquid was prepared by mixing 4.1g of fumed silica (fumed silica 200), 11.6g of morpholine and 15g of water, and the liquid A was gradually added thereto. 24g of water was further added thereto, and the mixture was stirred for 3 hours.

The resulting mixture was placed in a 200cc stainless steel autoclave equipped with a polytetrafluoroethylene inner cylinder and allowed to stand at 200 ℃ for 24 hours to react. After the reaction, the reaction mixture was cooled, and the precipitate was recovered by removing the clear solution by decantation. The obtained precipitate was washed with water for 3 times, filtered, and dried at 120 ℃. This was calcined at 550 ℃ for 6 hours under an air stream to obtain zeolite.

Powder XRD was measured, and as a result, the zeolite was of the CHA type (framework density: 14.6T/1,000)) A silicoaluminophosphate. In addition, the skeleton density was determined by constitution with reference to Atlas Of Zeolite structures types (1996, ELSEVIER) Of IZA. The test materials were heated and dissolved in an aqueous hydrochloric acid solution, and ICP analysis was performed, but the composition ratios (molar ratios) of the respective components to the total of aluminum, phosphorus, and silicon in the skeleton structure were 0.13 for silicon, 0.49 for aluminum, and 0.38 for phosphorus.

The adsorption isotherm at 25 ℃ of this zeolite is shown in FIG. 4. As is clear from FIG. 4, the zeolite rapidly adsorbs water vapor at a relative vapor pressure of 0.07 to 0.10, and the amount of change in the adsorption amount within the relative vapor pressure range of 0.05 to 0.20 is 0.25 g/g.

And, a process for preparing the zeolite²⁹The record of the Si-MAS-NMR spectroscopy is shown in FIG. 5. In that²⁹On the Si-NMR spectrum, the integrated intensity area of-108 ppm to-123 pp is 9.2% and-70 ppm to-92 pp is 52.6% relative to the signal intensity of-70 ppm to-123 ppm.

Example 3

After 72g of aluminum isopropoxide was added to 128g of water and stirred, 38.76g of 85% phosphoric acid was added thereto and stirred for 1 hour. To the solution was added 1.2g of fumed silica (fumed silica 200), and 89.3g of a 35% tetramethylammonium hydroxide (TEAOH) aqueous solution was further added and stirred for 3 hours. The mixture was placed in a 500cc stainless steel autoclave equipped with a polytetrafluoroethylene inner cylinder, and reacted at 185 ℃ for 60 hours while stirring at 100 rpm. After the reaction, the reaction mixture was cooled, and the product was separated by centrifugation, washed with water, and dried at 120 ℃. This was calcined at 550 ℃ for 6 hours under an air stream to obtain zeolite.

When the powder XRD was measured, it was a CHA-type silicoaluminophosphate (framework density: 14.6T/1,000)

). The test materials were heated and dissolved in an aqueous hydrochloric acid solution, and ICP analysis was performed, but the composition ratios (molar ratios) of the respective components to the total of aluminum, phosphorus, and silicon in the skeleton structure were 0.03, 0.50, and 0.47.

The adsorption isotherm at 25 ℃ of this zeolite is shown in FIG. 6. As shown in FIG. 6, this zeolite also exhibited an adsorption isotherm similar to that of the zeolite of example 2, rapidly adsorbing water vapor at a relative vapor pressure of 0.07 to 0.10, and the amount of change in the adsorption amount was 0.23g/g with a relative vapor pressure range of 0.05 to 0.20.

The heat of adsorption was 58.2 kJ/mol.

Example 4

Using an adsorption isotherm measuring apparatus [ ベルソ - ブ 18: japanese ベル (strain) ] was examined for SAPO-34 (manufactured by UOP LLC). The water vapor adsorption isotherm of the adsorption process at 40 ℃ for this SAPO-34 is shown in FIG. 7. In addition, the adsorption isotherm was measured under the following conditions: the air high temperature tank temperature of 50 ℃, the adsorption temperature of 40 ℃, the initial introduction pressure of 3.0torr, the number of introduction pressure set points of 0, the saturated vapor pressure of 55.33mmHg, and the equilibrium time of 500 seconds.

On the other hand, the adsorption isotherm of the desorption process was measured by a gravimetric adsorption amount measuring apparatus in which a gas generating unit, a pressure measuring unit, and a vapor introducing unit in which a gas discharging unit was disposed in an air thermostatic chamber were connected to a magnetic levitation balance [ japan ベル (ltd) ]. The adsorption isotherm of the desorption process was measured by measuring the weight change at 120 ℃ in the air high-temperature tank and 90 ℃ in the desorption temperature at 50Torr of the discharged water vapor. The results are shown in FIG. 7.

Assuming that the vehicle is a general vehicle, the in-vehicle air conditioner may be set to conditions of T1 ═ 90 ℃, T2 ═ 40 ℃, and T0 ═ 10 ℃. In this case, when the desorption-side relative vapor pressure Φ 1 becomes 0.11 and the adsorption-side relative vapor pressure Φ 2 becomes 0.17, it can be judged that the difference in the adsorption amounts of Φ 1 and Φ 2 is 0.21 g/g. When the adsorption amount difference exceeds the target 0.15g/g, it is considered that the adsorption amount difference is sufficient as an air conditioner for a vehicle used in a general vehicle.

When T1, T2, and T0 were 90 ℃, 40 ℃, and 5 ℃, the adsorption amount between 0.11 and 0.17 of Φ 1 and 0.17 reached 0.20g/g, and exceeded the target adsorption amount difference of 0.15g/g, which is considered to be sufficient as an air conditioner.

Depending on the region, the temperature of the cooling water T2 may rise to about 45 ℃. In this case, a condition that T0 ═ 10 ℃ is obtained at T1 ═ 90 ℃ is considered. The adsorption isotherm of the adsorption process at 45 ℃ was determined with ベルソ - ブ 18. The adsorption isotherms of the desorption process with 90 ℃ are shown together in FIG. 8. The determination of the adsorption isotherm at 45 ℃ was carried out under the following conditions: the air high temperature tank temperature was 65 ℃, the adsorption temperature was 45 ℃, the initial introduction pressure was 3.0torr, the number of introduction pressure set points was 0, the saturated vapor pressure was 55.33mmHg, and the equilibrium time was 500 seconds. At 90 ℃ T1, 40 ℃ T2 and 10 ℃ T0, the desorption relative humidity Φ 1 is 0.14 and the intake relative humidity Φ 2 is 0.13.

Thus, it was found that even when the relative vapor pressure on the desorption side was higher than the relative vapor pressure on the intake side, the difference in the amount of adsorption could reach 0.16g/g in example 4 having temperature dependence. It is considered that the adsorption heat pump using the water vapor adsorbent of example 4 can be sufficiently operated even in a high-temperature place.

Reference example

115.3g of 85% phosphoric acid was slowly added to 173.4g of water, and 68g of pseudoboehmite (containing 25% water, manufactured by コンデア) was slowly added thereto and stirred for 3 hours. 30g of fumed silica was added thereto, 87.2g of morpholine and 242.3g of water were added thereto, and the mixture was stirred for 4.5 hours. The mixture was allowed to stand at room temperature overnight to be matured, and the mixture was placed in an induction stirring type 1L stainless steel autoclave equipped with a polytetrafluoroethylene inner cylinder, stirred at 60rpm, and reacted at 200 ℃ for 24 hours. After the reaction, the reaction mixture was cooled, and the precipitate was recovered by removing the clear solution by decantation. The precipitate thus obtained was washed with water, filtered and dried at 120 ℃. It was fired at 550 ℃ under a stream of air to give a zeolite. The zeolite was measured for XRD and was, if at all, CHA-type. The test materials were heated and dissolved in an aqueous hydrochloric acid solution, and ICP analysis was performed, but the composition ratios (molar ratios) of the respective components to the total of aluminum, phosphorus, and silicon in the skeleton structure were 0.12 for silicon, 0.49 for aluminum, and 0.39 for phosphorus.

The adsorption isotherm at 25 ℃ of this zeolite is shown in fig. 9. As is clear from FIG. 9, the zeolite rapidly adsorbs water vapor from an adsorption start state where the relative vapor pressure is extremely low, and the amount of change in the adsorption amount is 0.1g/g or less in the relative vapor pressure range of 0.05 to 0.20. Therefore, it is not suitable as an adsorbent for adsorption heat pumps.

The results of Si-MAS-NMR measurement under the same conditions are shown in FIG. 10. In that²⁹On the Si-MAS-NMR spectrum, the integrated intensity area of the signal intensity of-108 ppm to-123 ppm was 13.0% with respect to the integrated intensity area of the signal intensity of-70 ppm to-123 ppm. And the integrated intensity area of signal intensities of-70 ppm to-92 ppm was 51.6%. Thus, it is considered that when the peak strength is as high as about-110 ppm, even the CHA-type silicoaluminophosphate is not suitable as an adsorbent to be regenerated by a heat source of 100 ℃ or lower. The heat of adsorption was 61.3 kJ/mol.

Comparative example 1

The difference in the adsorption amount of the intermediate porous molecular sieve (FSM-10) is more than 0.25g/g in the range of relative vapor pressure of 0.20 to 0.35 (FIG. 14, line 4 of JP-A-9-178292; refer to FSM-10). However, the adsorption amount is small in the range of 0.05 to 0.30 in relative vapor pressure, which is an example of the operation of the adsorption heat pump of the present invention. In this range, the change in the adsorption amount is large in the range of the relative vapor pressure of 0.15 to 0.30, but the difference in the adsorption amount at this time is 0.08g/g, and the performance as an adsorption heat pump is poor.

Comparative example 2

The reaction solution was measured using an adsorption isotherm measuring apparatus [ ベルソ - ブ 18: jp ベル (ltd) ] shows a water vapor adsorption isotherm at an adsorption temperature of 25 ℃ in the measurement of silica gel type a [ fuji シリシア chemical (ltd) ] known as an adsorbent suitable for use in an adsorption heat pump, in fig. 11. The measurement was performed under the same conditions as those for SAPO-34 in example 1. According to the adsorption isotherm of the silica gel type A shown in FIG. 11, the silica gel type A has an adsorption amount substantially proportional to the relative vapor pressure in the range of 0to 0.7. However, like the intermediate porous molecular sieve or the porous aluminophosphate molecular sieve, the adsorption amount of the A-type silica gel changes by only 0.08g/g in the range of relative vapor pressure of 0.15 to 0.30. Although adsorption heat pumps using silica gel as an adsorbent are commercially available, the apparatus has to be large because of the small difference in the amount of adsorption.

Comparative example 3

According to AFI type (framework density: 17.5T/1,000) as a porous aluminophosphate molecular sieve shown in FIG. 12) Adsorption isotherm for ALPO-5 of zeolites [ Colloid PolymSci277, p83-88(1999), quoted from FIG.1 (adsorption temperature 30 ℃ C.)]The adsorption isotherm (2) shows that the adsorption amount of ALPO-5 rapidly increases in the range of relative vapor pressure of 0.25 to 0.40 and can be adsorbed/desorbed in the range of relative vapor pressure of 0.05 to 0.3, but the change in adsorption amount in the range of relative vapor pressure of 0.15 to 0.30 is 0.14 g/g.

Although the present invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.

The present application is based on Japanese laid-open application (Japanese patent application No. 2001-.

Possibility of industrial utilization

One of the features of the present invention is that the adsorbent having the above-described characteristics is used in an adsorption unit of an adsorption heat pump. Since a large change in the amount of adsorption can be obtained with a narrow range of relative vapor pressure change, it is suitable for an adsorption heat pump in which the amount of adsorbent to be filled is limited, for example, for an air conditioner for a vehicle.

The adsorption heat pump of the present invention can regenerate (desorb) the adsorbent at a low temperature because of a large difference in the amount of moisture adsorbed by the adsorbent/desorbed, and therefore, can efficiently drive the adsorption heat pump using a low-temperature heat source as compared with the conventional one. Further, since the adsorbent used in the present invention changes its adsorption amount more in the same relative vapor pressure range as compared with conventional silica gel or zeolite, the use of an adsorbent having substantially the same weight can produce a greater dehumidifying effect.

That is, if the adsorbent of the present invention is used, an adsorption heat pump driven by a heat source having a relatively low temperature of 100 ℃ or lower can be provided.

Claims

1. A method of using an adsorbent material comprising heating an adsorbent material having an adsorbate to desorb the adsorbate, cooling the dried adsorbent material to a temperature for adsorption of the adsorbate, and reusing for adsorption of the adsorbate, characterized by: (1) the adsorbent contains zeolite containing aluminum and phosphorus in a framework structure, (2) the adsorbent is a water vapor adsorbent, and has a range in which a relative vapor pressure phi 2b is 0.115 to 0.18 inclusive during an adsorption operation in an adsorption/desorption unit and a relative vapor pressure phi 1b is 0.1 to 0.14 inclusive during a desorption operation in the adsorption/desorption unit, and the difference in the amount of adsorption of the adsorbent, which is determined by the following formula, is 0.15g/g or more:

the adsorption capacity difference is Q2-Q1,

wherein,

q1 represents the adsorption amount at Φ 1b determined from the water vapor desorption isotherm measured at the desorption operating temperature T3 in the adsorption/desorption unit,

q2 represents the adsorption amount at Φ 2b determined from the water vapor adsorption isotherm measured at the adsorption operation temperature T4 in the adsorption/desorption unit,

while

The relative vapor pressure Φ 1b at the time of desorption operation in the adsorption/desorption unit is ═ equilibrium vapor pressure at the refrigerant temperature T2 for cooling the condenser/[ equilibrium vapor pressure at the heat medium temperature T1 for heating the adsorption/desorption unit ],

the relative vapor pressure Φ 2b during the adsorption operation in the adsorption/desorption unit is ═ equilibrium vapor pressure at the cooling temperature T0 generated in the evaporation unit/equilibrium vapor pressure at the temperature T2 for cooling in the adsorption unit ]/[ equilibrium vapor pressure at the refrigerant temperature T2 in the desorption unit ],

wherein, T0 is 5-10 ℃, T1 is T3 is 90 ℃, and T2 is T4 is 40-45 ℃.

2. The method of using the adsorbent material of claim 1, wherein: t0 is 10 ℃ and T2 is 40 ℃.

3. The method of using the adsorbent material of claim 1, wherein: t0 is 5 ℃ and T2 is 40 ℃.

4. The method of using the adsorbent material of claim 1, wherein: t0 is 10 ℃ and T2 is 45 ℃.

5. The method of using the adsorbent material of claim 1, wherein: in the region where φ 1b and φ 2b are in the range of 0.115 to 0.18 inclusive and φ 1b is equal to or larger than φ 2b, the adsorbent has a region where the difference in the adsorption amount is in the range of 0.15g/g or larger.

6. The method of using the adsorbent material of claim 1, wherein: the zeolite contains a hetero atom in the framework structure.

7. The method of using the adsorbent material of claim 6, wherein: the zeolite has an aluminum to phosphorus to heteroatom presence ratio of:

0.001≤x≤0.3

wherein x is the molar ratio of heteroatoms to the sum of aluminum and phosphorus of the framework structure and heteroatoms,

0.3≤y≤0.6

wherein y is the molar ratio of aluminum to the sum of aluminum and phosphorus and heteroatoms of the framework structure,

0.3≤z≤0.6

wherein z is the molar ratio of phosphorus to the sum of aluminum and phosphorus of the framework structure and heteroatoms.

8. The method of using the adsorbent material of claim 1, wherein: the zeolite has a framework density of 10.0T/1,000

³Above, 16.0T/1,000

³The following zeolites.