KR20220164171A - Apparatus for water recovery using rapid thermal swing adsorption and water recovery process using the same - Google Patents

Abstract

A water recovery device using high-speed thermal swing adsorption according to the present invention includes: four or more beds that adsorb moisture and have bundles of hollow fiber absorbents in the form of hollow fibers with a cavity in the middle of the cross section located thereinside; a cooling water supply unit that supplies cooling water set according to an operation sequence to the hollow interior of the hollow fiber adsorbent to each of the four or more beds; a gas supply unit that supplies a moisture-saturated gas set according to an operation sequence to each of the four or more beds; a steam supply unit that supplies steam set according to an operation sequence to each of the four or more beds into the hollow interior of the hollow fiber adsorbent; and a valve system that converts the cooling water, the moisture-saturated gas, and the steam at regular time intervals so that the four or more beds sequentially operate in an adsorption stage, heating stage, desorption stage, and cooling stage.

Description

Water recovery device using high-speed thermal swing adsorption and water recovery process through it

The present invention relates to a water recovery device using high-speed thermal swing adsorption and a water recovery process therethrough, and more particularly, to a device and process for recovering water saturated with gas in a cooling tower mainly used in power plants or chemical plants.

The share of renewable energy such as solar energy and wind power in global energy consumption accounts for 17.5% as of 2015, and is expected to reach 21% by 2030, and the target and scope of use are gradually increasing. Along with such research on renewable energy, efforts to efficiently use limited water resources through water reuse are being actively conducted worldwide. Some countries, such as Israel and Kuwait, where water shortages are severe, reuse more than 80% of the treated sewage water generated annually, and Singapore and Spain, which are highly dependent on water imports, also show a high water reuse rate. Korea also encourages reuse of water such as gray water, sewage treatment water, and rainwater, but as of 2015, the proportion of reused water out of the total water consumption of 37.2 billion tons is 1.3 billion tons, which is disappointing. As such, various energy recovery methods are being researched and developed due to interest in energy recovery, but awareness of the reuse of water as a renewable resource is insufficient.

In particular, facilities such as power plants such as thermal power plants, oxy-fuel flue gas, and chemical plants configure a device to recover water saturated in gas discharged from a cooling tower to recycle water. are doing A device for recovering water from a cooling tower used in this way generally collects water by condensing moisture from a moisture-saturated gas using a membrane condenser. However, the amount of water that a membrane condenser can collect is relatively small compared to its large volume. That is, a disadvantage in that the cost consumed when recovering water is greater than the cost of newly supplying water may occur. Accordingly, there is a need for a water recovery device capable of recovering water with a smaller volume and at a lower cost compared to a conventional water recovery device using a membrane condenser.

Korean Patent Registration No. 10-2161064

The present invention is an invention made to solve the above problems, and the problem to be solved by the present invention is to increase the adsorption amount of water by supporting the H ₂ O adsorbent (H ₂ O sorbent) on a hollow fiber. An object of the present invention is to provide a water recovery device using high-speed thermal swing adsorption that can be designed with a small volume and enhances thermal energy efficiency through a heat integration scheme structure, and a moisture recovery process through the same.

The above and other objects and advantages of the present invention will become apparent from the following description of preferred embodiments.

The above object is to adsorb moisture and to have four or more beds in which a hollow fiber adsorbent bundle having a cavity in the middle of the cross section is located inside, and the cooling water set according to the operation sequence in each of the four or more beds is applied to the hollow fiber adsorbent. A cooling water supply unit supplying a cooling water supply unit to the inside of the hollow, a gas supply unit supplying a gas saturated with moisture set according to the operation sequence to each of the four or more beds, and steam set according to the operation sequence to each of the four or more beds to the hollow fiber adsorbent A valve for converting the cooling water, the moisture-saturated gas, and the steam at regular time intervals so that the steam supply unit supplied into the hollow and the four or more beds sequentially operate in the adsorption step, heating step, desorption step, and cooling step This is achieved by a water recovery device using high speed thermal swing adsorption comprising a system.

Preferably, the hollow fiber adsorbent includes zeolite particles and polyamide imide (PAI), and has a lumen layer on an inner wall of the hollow to block penetration of the cooling water and the steam into the hollow fiber adsorbent. may have been formed.

Preferably, the hollow fiber adsorbent may be cooled or heated by exchanging thermal energy with a thermal fluid including the cooling water and the steam passing through the hollow interior.

Preferably, both ends of the hollow fiber adsorbent bundle may be sealed with a curable resin to prevent the cooling water and steam from contacting the surface of the hollow fiber adsorbent when cooling water and steam are supplied to the bed.

Preferably, the four or more beds sequentially and repeatedly perform the operation sequence of the adsorption step, heating step, desorption step, and cooling step, but all of the adsorption step, heating step, desorption step, and cooling step are performed in the same operating sequence. The adsorption step is performed simultaneously in different beds, and the adsorption step is to adsorb moisture from the moisture-saturated gas to the hollow fiber adsorbent by contacting the moisture-saturated gas supplied from the gas supply unit with the hollow fiber adsorbent, and the adsorption heat generated It is recovered through the cooling water passing through the hollow and transferred to the bed performing the heating step, and the heating step is the integrated heat recovered through the cooling water from the bed performing the cooling step in the bed performing the adsorption step in the previous operation sequence The hot water having is supplied into the hollow and heated, and the desorption step is to desorb moisture from the hollow fiber adsorbent by heating the bed on which the heating step has been performed in the previous operation sequence with steam supplied into the hollow, and the cooling step may be to cool the bed heated in the desorption step using cooling water supplied into the hollow, recover integrated heat, and transfer the hot water having the recovered integrated heat to the bed performing the heating step.

Preferably, the water recovery device using high-speed thermal swing adsorption may recover water in the form of steam in the desorption step.

Preferably, the gas supply unit may lower the desorption temperature by lowering the pressure inside the four or more beds through a blower or a vacuum pump in the desorption step.

Preferably, the four or more beds may be in parallel contact with a moisture-saturated gas and a hollow fiber adsorbent.

In addition, the above object is achieved by a water recovery process using high-speed thermal swing adsorption using the water recovery device according to the above description.

According to the present invention, the water recovery device using high-speed thermal swing adsorption and the water recovery process through the same increase the adsorption amount of water through the structure in which the H ₂ O adsorbent is supported on the hollow fiber, thereby reducing the volume required for adsorption and adsorption. Energy efficiency can be increased by recovering thermal energy through a heat integration scheme that recycles thermal energy in the overcooling process in the desorption process. Through this, the present invention can efficiently recover water in a small space and with little energy, and can be applied to any process in which water-saturated gas is discharged.

However, the effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description below.

1 is a block diagram of a water recovery device using high-speed thermal swing adsorption according to an embodiment of the present invention.
FIG. 2 is a block diagram showing operations of an adsorption step, a heating step, a desorption step, and a cooling step of the bed shown in FIG. 1 .
3A to 3C are views illustrating an example of an operation sequence of a water recovery device using high-speed thermal swing adsorption according to an embodiment of the present invention.
FIG. 4A is a diagram explaining the configuration of a hollow fiber adsorbent of a water recovery device using high-speed thermal swing adsorption according to an embodiment of the present invention.
Figure 4b is a cross-sectional view of the hollow fiber adsorbent prepared in Figure 4a.
4C is a view showing a SEM photograph of the hollow fiber adsorbent of the water recovery device using high-speed thermal swing adsorption according to an embodiment of the present invention.
4D is a schematic diagram of hollow fiber adsorbent bundles positioned within a bed.
5 is a bed configuration diagram of a water recovery device using high-speed thermal swing adsorption according to an embodiment of the present invention.
6 is a diagram showing water adsorption isotherms of the hollow fiber adsorbent of the water recovery device using high-speed thermal swing adsorption according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Terms and words used in this specification are terms selected in consideration of functions in the embodiments, and the meanings of the terms may vary depending on the intention or practice of the invention. Therefore, the terms used in the embodiments to be described later, when specifically defined in the present specification, follow the definition, and when there is no specific definition, they should be interpreted as meanings generally recognized by those skilled in the art.

1 is a block diagram of a water recovery device using high-speed thermal swing adsorption according to an embodiment of the present invention.

FIG. 2 is a block diagram showing operations of an adsorption step, a heating step, a desorption step, and a cooling step of the bed shown in FIG. 1 .

1 and 2, a water recovery device using high-speed thermal swing adsorption according to an embodiment of the present invention includes a bed 100, a cooling water supply unit 200, a gas supply unit 300, and a steam supply unit (not shown). and a valve system (not shown).

A water recovery device using high-speed thermal swing adsorption according to an embodiment of the present invention includes four or more beds 100.

Each bed 100 includes a bundle of hollow fiber adsorbents adsorbing moisture from a moisture-saturated gas and desorbing the adsorbed moisture. The hollow fiber adsorbent bundle is formed by bundling hollow fiber adsorbents having a cavity in the middle of the cross section, and includes zeolite particles and polyamide imide (PAI), and the cooling water and the It has a structure in which a lumen layer is formed to block steam from penetrating into the hollow fiber adsorbent.

The hollow fiber adsorbent formed of zeolite particles and polyamideimide adsorbs moisture by contacting the moisture-saturated gas passing through the bed, and transfers the heat to the cooling water and hollow fiber adsorbent to recover heat generated in the process. Steam passes through the hollows of the hollow fiber adsorbent to absorb and transfer heat. At this time, the cooling water and steam do not directly contact the hollow fiber adsorbent formed of zeolite particles and polyamideimide due to the lumen layer formed on the hollow inner wall of the hollow fiber adsorbent and do not interfere with adsorption and desorption of the hollow fiber adsorbent.

Conventional membrane condensers require energy to cool the gas because moisture is recovered from the gas by cooling the saturated gas so that condensation occurs on the surface of the membrane. In addition, since the membrane condenser has a scheme in which the introduced gas passes vertically through the membrane, the pressure drop of the gas is very large. In other words, the total energy required in conventional membrane condensers can be expressed as the sum of the energy for cooling the gas and the energy for blowing the gas, and the latent heat (condensation heat) generated as water condenses on the surface of the membrane condenser are all lost to the coolant. However, the water recovery device using high-speed thermal swing adsorption according to an embodiment of the present invention has a structure that increases energy efficiency by recovering and reusing condensation heat.

The bed 100 has hollow fiber adsorbent bundles located therein, and both ends of the hollow fiber adsorbent bundles are sealed with curable resin so that when cooling water and steam are supplied to the bed 100, the cooling water and the steam are formed on the surface of the hollow fiber adsorbent. The thermal fluid including steam and cooling water passes through the hollow fiber adsorbent bundle only through the hollow in which the lumen layer is formed. In the adsorption step, heat of adsorption is generated to increase the temperature of the hollow fiber adsorbent, thereby impairing the adsorption capacity of moisture, thereby increasing the adsorption efficiency by passing cooling water through the structure.

The cooling water supply unit 200 supplies cooling water to each of the four or more beds 100 using a pump or the like. At this time, the cooling water supply unit 200 supplies cooling water according to a predetermined operation sequence to each of the four or more beds 100 through valve control through a valve system. At this time, the cooling water supply method of the cooling water supply unit 200 and the type of cooling water may be generally used.

The gas supply unit 300 is individually connected to the sides of the four beds 100 and supplies moisture-saturated gas to each of the four or more beds 100 according to a predetermined operation sequence through valve control through a valve system. At this time, as a gas supply method of the gas supply unit 300, a method generally used in a carbon dioxide capture device or a water recovery device may be applied. In addition to supplying gas to the four beds 100 in the adsorption step through a blower or a vacuum pump, the gas supply unit 300 controls the pressure inside the bed 100 in the desorption step. can play a role in lowering The gas supply unit 300 reduces the energy consumption of the process by lowering the pressure inside the bed 100 through a blower or a vacuum pump in the desorption step to lower the desorption temperature, and denaturation of the hollow fiber adsorbent reduce the rate

The steam supply unit supplies steam set to each of the four or more beds according to an operation sequence into the hollow of the hollow fiber adsorbent. At this time, steam supplied through the steam supply unit may be steam supplied from a facility or factory in which the water recovery device of the present invention is installed, or steam supplied from an external source may be used. In the present invention, the high-temperature steam supplied as a heat source for performing the desorption step in each bed 100 is adjusted through a valve system to the bed performing the desorption step according to the operation sequence among the four beds 100 By supplying high-temperature steam, it is heated to the temperature at which the desorption reaction occurs. Preferably, high-temperature steam is used to raise the temperature of the bed for performing the desorption step, but it is not limited thereto and various methods for supplying a heat source may be used. At this time, the high-temperature steam supplied to the bed 100 is supplied in the form of steam in the supply process, and is discharged in a condensate state after heating the bed 100. As an example, the high-temperature steam used in the present invention, when the present invention is installed in a power plant facility, can be used in a way in which the high-temperature steam is supplied and used through the power plant facility, and then the condensate is transferred again and circulated.

In the present invention, four or more beds 100 are used instead of one bed, and the four or more beds 100 individually perform different process steps rather than simultaneously performing the same operation and process. At this time, the valve system switches the supply of gas, cooling water, and steam at regular time intervals so as to sequentially operate in adsorption, heating, desorption, and cooling stages.

More specifically, the four or more beds 100 sequentially repeat the operation sequence of the adsorption step, heating step, desorption step, and cooling step, but all of the adsorption step, heating step, desorption step, and cooling step in the same sequence are necessarily performed simultaneously on one or more beds. That is, in the present invention, the four or more beds 100 are necessarily performed simultaneously in at least one bed 100 in the same sequence according to the operation sequence, the adsorption step, the heating step, the desorption step, and the cooling step, and four or more beds ( 100) sequentially performs an adsorption step, a heating step, a desorption step, and a cooling step, so that the adsorption step, the heating step, the desorption step, and the cooling step are performed by different beds within one operation sequence. Through this, in the present invention, all four or more beds 100 are simultaneously adsorbed, heated, desorbed, and cooled based on the same operation sequence, and the adsorbed, heated, desorbed, and cooled steps are sequentially performed. is repeated in each bed.

In the present invention, the adsorption step injects the moisture-saturated gas supplied from the gas supply unit 300 into the bed 100 and contacts the hollow fiber adsorbent bundle located inside the bed 100 to remove moisture contained in the gas into the hollow fiber adsorbent and the heat of adsorption is recovered using the cooling water passing through the hollows of the hollow fiber adsorbent at the same time, and the generated hot water is transferred to the bed for performing the heating step. In the heating step, the bed on which the adsorption step was performed in the previous operation sequence is heated using hot water having adsorption heat recovered in the adsorption step and hot water having integrated heat recovered in the cooling step.

Next, in the desorption step, the bed subjected to the heating step in the previous operation sequence is heated with supplied high-temperature steam to desorb moisture from the hollow fiber adsorbent, and in the cooling step, through the hollow fiber adsorbent of the bed heated in the desorption step. The integrated heat is recovered by supplying cooling water, and the hot water having the recovered integrated heat is delivered to the bed for performing the heating step. Since a large amount of sensible heat is wasted in the cooling process of the cooling step after the desorption step, the amount of cooling water in the cooling step is adjusted and hot water is created, and the hot water thus produced is supplied to the bed performing the heating step to perform heat integration. . By performing the heat integration in this way, the thermal energy of the process is reduced, and steam usable during desorption can be generated. In addition, the present invention has the advantage that water is recovered in the form of high-temperature steam having energy close to that of the high-temperature steam supplied in the desorption step.

As described above, in the water recovery device using high-speed thermal swing adsorption according to an embodiment of the present invention, four or more different beds 100 each perform different steps of the above-described adsorption step, heating step, desorption step, and cooling step. At this time, the adsorption heat generated in the bed performing the adsorption step is recovered through cooling water and transferred to the bed performing the heating step, and the combined heat recovered in the cooling step after desorption is also recovered through cooling water to perform the heating step It is possible to significantly reduce the energy that needs to be additionally supplied in the desorption step by raising the temperature of the bed for performing the heating step by transferring the heat to the bed.

In the conventional membrane condenser, since water recovery increases as the gas temperature is high and the inlet temperature is low, energy for increasing the gas temperature and lowering the inlet temperature is required. On the other hand, the above-described water recovery device using high-speed thermal swing adsorption according to an embodiment of the present invention directly adsorbs moisture saturated in gas using a hollow fiber adsorbent and increases the thermal shear rate through the hollow structure and the lumen layer, By recovering and recycling adsorption heat and integration heat through cooling water, a high water recovery rate can be secured using relatively low energy.

3A to 3C are diagrams for explaining an example of an operation sequence of a water recovery device using high-speed thermal swing adsorption according to an embodiment of the present invention. FIG. 3A is an operation state of first to fourth beds in one operation sequence. 3b shows the entire operation sequence of FIG. 3a, and FIG. 3c shows the simplified operation sequence of FIG. 3b.

In FIGS. 3A to 3C , a water recovery device using high-speed thermal swing adsorption using a total of four beds of first to fourth beds 110 to 140 will be described as an example of an operation sequence. However, the number of beds is not limited to four, and means at least four.

Also, in FIG. 3B, arrows in a horizontal direction mean supply to the bore side of the hollow fiber adsorbent, and arrows in a vertical direction mean supply to the shell side of the hollow fiber adsorbent.

In one operation sequence, the first bed 110 performs an adsorption step, passing a moisture-saturated gas into the first bed 110 to contact the hollow fiber adsorbent located inside the first bed 110 to adsorb moisture (water), and at the same time, cooling water (CW) is passed through the hollow of the hollow fiber adsorbent bundle to recover the adsorption heat generated in the adsorption step through the cooling water and perform the heating step of the generated hot water. Transfer to 2nd bed 120.

In the same operating sequence, the second bed 120 performs the heating step in the current operating sequence after performing the adsorption step in the previous operating sequence, and the hot water having the heat of adsorption recovered in the adsorption step from the first bed 110 It is heated by receiving hot water (HW) having integrated heat recovered through cooling water from the fourth bed 140 performing the cooling step.

And in the same operating sequence, the third bed 130 performs the second heating step in the current operating sequence after performing the first heating step in the previous operating sequence, from the fourth bed 140 performing the cooling step. The third bed 130 is heated by receiving the hot water having integrated heat recovered in the transferred cooling step.

As such, in the present invention, the heating step is performed as an intermediate process immediately before proceeding to the desorption step after the adsorption step. By preheating the bed before performing the desorption step through the heat integration structure, it is possible to reduce the thermal energy required in the desorption step.

In addition, in the same operation sequence, the third bed 130 performs the desorption step in the current operation sequence after performing the heating step in the previous operation sequence, and the temperature at which the desorption step can be performed by the supplied high-temperature steam It is heated to carry out the desorption reaction. At this time, the steam supplied to the third bed 130 passes through the hollow inside of the hollow fiber adsorbent located in the third bed 130 to effectively transfer heat to the hollow fiber adsorbent, thereby reducing thermal energy required in the desorption step.

Through the desorption step, the third bed 130 desorbs all the moisture adsorbed on the hollow fiber adsorbent and is regenerated to adsorb moisture again. Moisture recovered by being desorbed from the hollow fiber adsorbent through the desorption step has the form of steam. The steam thus recovered may be delivered to a bed for performing the desorption step and used to heat the bed for performing the desorption step, or may be delivered to a bed for performing the heating step and used for heating the bed, or may be used for vapor sale. For example, when the moisture in the gas is saturated at 40°C, it is a vapor at 40°C, but in case of desorption, the temperature must rise to 110°C or higher, so the desorbed moisture is recovered in the form of steam at 100°C or higher. Steam can be recycled or sold as above.

In addition, in the same operation sequence, the fourth bed 140 performs a cooling step in the current operation sequence after performing the desorption step in the previous operation sequence, and the bed heated to a high temperature in the desorption step through the cooling water provided from the cooling water supply unit While cooling, the combined heat is recovered, and the hot water having the integrated heat is transferred to the third bed 130 performing the heating step and recycled.

In the present invention, the thermal energy required in the desorption step can be reduced by recovering integrated heat, such as thermal energy from the desorption step, while cooling the bed in the cooling step, and supplying the integrated heat to the bed performing the heating step for use in the heating step.

The adsorption step, heating step, desorption step and cooling step described above are carried out simultaneously in different beds in the same sequence. And, as shown in FIG. 3B, after the adsorption step, the heating step, the desorption step, and the cooling step are simultaneously performed in different beds in one sequence, each bed performs the next step respectively in the next operation sequence. In this process, the energy generated or provided in each step is recovered by the cooling water and transferred to the bed performing the other steps for use, thereby reducing the renewable energy required in the desorption step.

Figure 4a is a view explaining the configuration of the hollow fiber adsorbent of the water recovery device using high-speed thermal swing adsorption according to an embodiment of the present invention, Figure 4b is a cross-sectional view of the hollow fiber adsorbent manufactured in Figure 4a, Figure 4c is a view showing a SEM photograph of the hollow fiber adsorbent of the water recovery device using high-speed thermal swing adsorption according to an embodiment of the present invention, and FIG. 4d is a configuration diagram of the hollow fiber adsorbent bundle located in the bed. At this time, in FIGS. 4A to 4D, the thickness ratio of the hollow fiber adsorbent 101 and the lumen layer 102 is exaggerated for convenience of explanation.

4A to 4D, the hollow fiber adsorbent 101 of the water recovery device using high-speed thermal swing adsorption according to an embodiment of the present invention is spinning after carrying zeolite particles in polyamideimide (PAI). ) to produce a hollow fiber sorbent. The hollow fiber adsorbent 101 formed of such zeolite and polyamideimide comes into contact with a gas saturated with moisture to adsorb and recover moisture from the gas. In addition, in the present invention, the hollow fiber adsorbent 101 has a lumen layer 102 formed on the inner wall of the hollow.

In the hollow fiber adsorbent shown in FIG. 4B, a hollow fiber adsorbent in which 75% by weight of zeolite is mixed with polyamideimide is formed using a dry-jet and wet-quench process, and Neoprene® is used as a precursor and crosslinking agents are mixed at a weight ratio of 11:89 to cross-link the neoprene, and then hollow fibers are formed using an ISCO syringe pump (Model No. of 1000D). The adsorbent was injected into the hollow to form a lumen layer 102 on the inner wall of the hollow. At this time, the crosslinking agent used may be TSR-633.

The characteristics of the hollow fiber adsorbent thus prepared are shown in Table 1.

Specification Value L _{f, exp} (m) 0.2 to 0.3 L _m,exp (m) 0.2 to 0.3 r _iD,f (mm) 0.1 to 0.3 r _oD,f (mm) 0.2 to 0.6

The lumen layer 102 can be confirmed through the cross-sectional view shown in FIG. 4B. The lumen layer 102 is impermeable, and the lumen layer 102 allows thermal fluids such as cooling water and steam passing through the hollows of the hollow fiber adsorbent 101 to directly interact with the hollow adsorbent 101 formed of zeolite and polyamideimide. avoid contact. In addition, the lumen layer 102 has a thin thickness and high thermal conductivity to increase heat transfer efficiency between the hollow fiber adsorbent and the thermal fluid passing through the hollow.

A plurality of the hollow fiber adsorbents 101 prepared as described above are packed and located in a bundle form inside the bed, and adsorb moisture saturated in the gas in contact with the gas. At this time, heat of adsorption is generated in the process of adsorbing moisture to the hollow fiber adsorbent, and the heat of adsorption increases the temperature of the hollow fiber adsorbent and lowers the adsorption efficiency. Therefore, the temperature of the hollow fiber adsorbent is lowered through the cooling water. The hollow fiber adsorbent of the present invention has a hollow inside through which the thermal fluid can pass, and the lumen layer prevents the thermal fluid from directly contacting the hollow fiber adsorbent. In the adsorption step, cooling water is directly flowed into the hollow of the hollow fiber adsorbent to effectively recover the adsorption heat generated in the hollow fiber adsorbent. In addition, in the desorption step, the temperature of the hollow fiber adsorbent can be raised to a temperature required for desorption using relatively low energy by passing steam directly through the hollow of the adsorbent to increase the hollow fiber. As such, the hollow fiber adsorbent of the present invention adsorbs moisture using an adsorbent rather than a condensation method, and has a high heat exchange efficiency with cooling water and steam through a hollow structure, so the pressure drop is small compared to conventional membrane condensers, and water is adsorbed by the adsorbent. As the volume is improved, the space required for the process is greatly reduced. The hollow fiber adsorbent according to an embodiment of the present invention has an energy requirement of about 50% compared to a conventional membrane condenser.

The model of the hollow fiber adsorbent according to the present invention is as shown in Equation 1. Equation 1 is a concentration profile of a feed gas saturated with moisture over time. The dimension is two-dimensional and the equation is developed in time and z-axis (longitudinal direction of the hollow fiber adsorbent).

(Equation 1)

In Equation 1, C _{g , i} [mol/m ³ ] represents the concentration of component i of the gas phase, u _g [m/s] represents the interstitial velocity of the gas flowing through the module empty volume, and D _ax [m ² /s] is the axial dispersion coefficient of the gas phase. ), and L _f [m] and z represent the length of the hollow fiber adsorbent (fiber sorbent length) and the normalized axial distance, respectively. And S _i [mol/m ³ ·s] represents the rate of decrease in the concentration of gas molecules due to the reaction and is calculated by Equations 2 and 3.

Equations 2 and 3 are reaction rate terms required for Equation 1, which quantitatively express the amount of H ₂ O adsorbed on the hollow fiber adsorbent.

(Equation 2)

(Equation 3)

In Equation 2, since N ₂ does not react with the hollow fiber adsorbent, its value is 0. In addition, q/∂t [mol-H ₂ O/kg-sorbent s] represents the reaction rate between H ₂ O and the hollow fiber adsorbent, r [mm] represents the radius of the hollow fiber adsorbent, subscript r _oD , r _iD , and r _fs represent the outer and inner diameters of the hollow fiber adsorbent and the diameter by Happel's free surface. And ρ _f [kg/m ³ ] and ε _f represent the density and porosity of the hollow fiber adsorbent. At this time, Happel's free surface theory is used to calculate the thickness of an imaginary layer created when a fluid flows in parallel through a cylinder shape.

The energy balance equations of the hollow fiber adsorbent and the bore side are expressed by Equations 4 to 6. Equations 4 to 6 represent the temperatures of the moisture-saturated gas and the heating medium.

(Equation 4)

(Equation 5)

(Equation 6)

In Equations 4 to 6, T [K] represents the temperature, subscripts f , g and h represent the hollow fiber, gas and heating medium in the hollow, h [W/m ² ºC] and λ [W/m ² ºC] represents a heat transfer coefficient and axial thermal dispersion. And U _hf [W / m ² ºC] represents the overall heat transfer coefficient between the heat transfer medium and the hollow fiber adsorbent, c _p,i represents the specific heat capacity of i component, Assume Tamb = 25 °C. Here, i component is a component included in the gas indicated by i, i means H ₂ O. Also, in Equation 4, κ represents an effectiveness factor of heat transfer between the hollow fiber adsorbent and the heat transfer medium. And the absence of the r-gradient of the hollow fiber adsorbent is compensated for by the use of κ .

The momentum balance of the bulk gas phase was modeled as shown in Equation 7 on the assumption that the gas in the bulk phase is gradually lost as adsorption occurs. Equation 7 is an equation representing the change in linear velocity of a gas saturated with water.

(Equation 7)

Equation 7 is the moment equation of the gas phase, and P [bar] means the pressure of the gas phase. The change in the superficial velocity of the gas flowing inside the module (bed) can be calculated using Equation 7.

Equations 1 to 7 above are equations representing the hollow fiber adsorbent, through which adsorption, heating, desorption, and cooling are repeated as shown in FIGS. 3B and 3C. Temperature and concentration profiles can be obtained for each cycle.

5 is a bed configuration diagram of a water recovery device using high-speed thermal swing adsorption according to an embodiment of the present invention.

Referring to FIG. 5, a gas saturated with water is injected into the shell side of the hollow fiber adsorbent inside the bed, and water is adsorbed on the hollow fiber adsorbent. After the adsorption is completed, it goes to the desorption step, and steam, a thermal fluid, is injected into the hollow of the hollow fiber adsorbent, and when the temperature of the hollow fiber adsorbent rises, water is desorbed by desorption heat. At this time, since the hollow fiber adsorbent and the gas flow in parallel and contact each other, the pressure buildup occurs less than in a membrane condenser that flows in a vertical direction. In addition, since it uses an adsorbent rather than a water recovery method based on a temperature difference, a separate cooler is not required.

6 is a diagram showing water adsorption isotherms of the hollow fiber adsorbent of the water recovery device using high-speed thermal swing adsorption according to an embodiment of the present invention.

A vapor sorption analyzer (TA instruments, VTI-SA+) was used as an experimental equipment to obtain the isotherm of FIG. and the desorption kinetic model was calculated based on the adsorption kinetics.

Equation 8 is the Toth isotherm model used to describe the equilibrium behavior of the hollow fiber adsorbent.

(Equation 8)

In Equation 8, q _eq [mol- H ₂ O /kg-sorbent] represents the amount of H ₂ O absorbed at equilibrium, _and q _m [mol- H ₂ O/kg- sorbent] denotes _{the maximum amount of H 2 O} adsorbed, b [bar ^-1 ] denotes the affinity constant, and p _H2O [bar] denotes the gaseous H ₂ O fraction. represents the partial pressure of H ₂ O in the gas phase, and n represents the Toth isotherm parameter.

The parameters of Equation 8 are defined by Equations 9 to 11, and Equations 9 to 11 all explain the form of the parameters of Equation 8.

(Equation 9)

(Equation 10)

(Equation 11)

In Equations 9 to 11, ΔH ₀ represents the isosteric heat of adsorption at zero loading, T ₀ represents the reference temperature, and b ₀ represents the affinity constant of the reference temperature. constant at T _{0 )} , q _{m 0,1} , q _{m 0,2} , η ₁ , η ₂ represent the exponential factor of q m _, and A and B are fitting parameters ).

Equation 12 represents an adsorption kinetic model of the hollow fiber adsorbent.

(Equation 12)

In Equation 12, K _ads [s ^-1 ] is the overall mass transfer coefficient between the hollow fiber adsorbent and H ₂ O during adsorption (overall mass transfer coefficients between fiber sorbent and H ₂ O at adsorption, and s _a means the regulation factor of the kinetic equation.

And from Equation 12, Equation 13, which is a desorption kinetic model of the hollow fiber adsorbent, is given.

(Equation 13)

In Equation 13, K _des [s ^{- 1} ] represents the overall mass transfer coefficient between _{the fiber sorbent and H 2 O} at desorption during desorption. At this time, the LDF model was used as a desorption kinetic model.

Here, Equations 12 and 13 are equations representing the rates of adsorption and desorption of H ₂ O from the hollow fiber adsorbent, and Equations 12 and 13 are substituted into Equations 2 and 4.

Although the present invention has been described in detail with preferred embodiments, the present invention is not limited to the above-described embodiments, and various modifications may be made by those skilled in the art within the scope of the technical idea of the present invention. It is possible.

100: bed
101: hollow fiber adsorbent 120: lumen layer
110: first bed 120: second bed
130: third bed 140: fourth bed
200: cooling water supply unit
300: gas supply unit

Claims (9)

Four or more beds adsorbing moisture and having a hollow fiber type hollow fiber adsorbent bundle having a cavity in the middle of the cross section located therein;
a cooling water supply unit supplying cooling water set to each of the four or more beds according to an operation sequence into the hollow of the hollow fiber adsorbent;
a gas supply unit supplying a gas saturated with moisture set according to an operation sequence to each of the four or more beds;
a steam supply unit supplying steam set to each of the four or more beds according to an operation sequence into the hollow of the hollow fiber adsorbent; and
a valve system for switching the cooling water, the moisture-saturated gas, and the steam at regular time intervals so that the four or more beds sequentially operate in an adsorption step, a heating step, a desorption step, and a cooling step;
A water recovery device using high-speed thermal swing adsorption comprising a. According to claim 1,
The hollow fiber adsorbent includes zeolite particles and polyamide imide (PAI), and a lumen layer is formed on an inner wall of the hollow to block penetration of the cooling water and the steam into the hollow fiber adsorbent. Water recovery device using thermal swing adsorption. According to claim 2,
The hollow fiber adsorbent is cooled or heated by exchanging thermal energy with the thermal fluid including the cooling water and the steam passing through the hollow, water recovery device using high-speed thermal swing adsorption. According to claim 1,
The hollow fiber adsorbent bundle is sealed at both ends with a curable resin to prevent the cooling water and the steam from contacting the surface of the hollow fiber adsorbent when cooling water and steam are supplied to the bed. Water recovery device using high-speed thermal swing adsorption. According to claim 1,
The four or more beds sequentially repeat the operation sequence of the adsorption step, heating step, desorption step, and cooling step, but all of the adsorption step, heating step, desorption step, and cooling step are the same operation sequence in different beds. performed simultaneously,
In the adsorption step, the moisture-saturated gas supplied from the gas supply unit is contacted with the hollow fiber adsorbent to adsorb moisture from the moisture-saturated gas to the hollow fiber adsorbent, and the generated adsorption heat is transferred through cooling water passing through the hollow fiber. recovered and transferred to a bed to undergo a heating step;
The heating step heats the bed on which the adsorption step was performed in the previous operation sequence by supplying hot water having integrated heat recovered through cooling water from the bed on which the cooling step was performed into the hollow,
The desorption step desorbs moisture from the hollow fiber adsorbent by heating the bed subjected to the heating step in the previous operation sequence with steam supplied into the hollow,
The cooling step cools the bed heated in the desorption step using the cooling water supplied into the hollow, recovers the integrated heat, and transfers the hot water having the recovered integrated heat to the bed performing the heating step. High-speed thermal swing adsorption Water recovery device using. According to claim 1,
A water recovery device using high-speed thermal swing adsorption recovers water in the form of steam in a desorption step. According to claim 1,
A water recovery device using high-speed thermal swing adsorption, wherein the gas supply unit lowers the desorption temperature by lowering the pressure inside the four or more beds through a blower or a vacuum pump in the desorption step. According to claim 1,
The four or more beds are a water recovery device using high-speed thermal swing adsorption in which a moisture-saturated gas and a hollow fiber adsorbent are in parallel contact. A water recovery process using high-speed thermal swing adsorption using the water recovery device according to claim 1.

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