Methods and systems for capture and release of target chemical species

Abstract

This invention relates to methods of employing multiple, different sorbents that capture and release a target chemical species in sequential order such that the release from the last sorbent has a higher concentration of the target species than otherwise could be attained by only using a single type of sorbent. The invention also employs one or more of these cascaded-sorbent units with energy recycling to attain higher energy efficiency defined as energy input per mass of target species collected. The invention also relates to a method to set the operating temperatures of the sorbents using a temperature control system that can exchange heat with passive or natural heat energy sources or heat sinks.

Description

[0001] Title of the Invention

[0002] METHODS AND SYSTEMS FOR CAPTURE AND RELEASE OF TARGET

[0003] CHEMICAL SPECIES

[0004] Field of the Invention

[0005] This invention relates to methods of employing multiple, different sorbents that capture and release a target chemical species in sequential order such that the release from the last sorbent has a higher concentration of the target species than otherwise could be attained by only using a single type of sorbent. The invention also employs one or more of these cascaded-sorbent units with energy recycling to attain higher energy efficiency which is as energy input per mass of target species collected. The invention also relates to a method to set the operating temperatures of the sorbents using a temperature control system that can exchange heat with passive or natural heat energy sources or heat sinks.

[0006] Background

[0007] Sorbents can refer to any material that adsorbs, absorbs, or captures a desired chemical species from a fluid, such as gas and / or liquid. When a fluid is contacted to a sorbent, the transfer of the target species in the fluid mobile phase to the sorbent can be characterized with a sorption isotherm. The sorption isotherm plots the relationship of the retention (adsorption, absorption, capture, uptake) of the target species in the sorbent as a function of the target species’ concentration in the fluid contacting the sorbent at a given temperature of the sorbent. The target species’ concentration in the fluid may be measured as a partial pressure if the fluid is a gas. The target species’ concentration in the sorbent may be measured in mass of the target species retained in the sorbent divided by the total mass of the sorbent.

[0008] Throughout this invention disclosure, the words capture, adsorb, absorb, load, and uptake are used interchangeably to describe the physical or chemical process of a target species molecule transferring from a fluid and into or onto a sorbent that the fluid is contacted to. The words release, regenerate, and desorb are used interchangeably to describe the physical or chemical process of a target species molecule transferring from a sorbent to a fluid that is contacted to it. The fluid can be a liquid or gas at various pressures and temperatures. The fluid that contacts the sorbent is referred to as an input or process fluid for the sorbent. The process of capturing the target species from the process fluid and moving the target species into or onto the sorbent will be referred to as loading the sorbent. The process fluid after contacting the sorbent is referred to as the processed fluid. The process fluid after contacting a collector or condensing element is referred to as the processed fluid. In this case, the target species moves from the process fluid and condenses or collects onto the collector or condensing element. The process of releasing the target species from the sorbent to the process fluid will be referred to as regenerating the sorbent. Methods to regenerate the sorbent can include but are not limited to heating the sorbent, decreasing the concentration of the target species in the process fluid, or a combination of both. If the process fluid is a gas, the concentration of the target species in the gas can be decreased by lowering the overall pressure of the gas, which will in turn, lower the target species partial pressure. Another method to regenerate the sorbent can include adding another chemical species in the process fluid that the sorbent preferentially captures, which will consequently cause the sorbent to release the target species to the process fluid in order to capture the other chemical species.

[0009] When the sorbent is regenerated, it will release the target species into the process fluid

[0010] (described above as the fluid contacting the sorbent), and the concentration of the target species in the process fluid will increase. The process fluid after contacting the regenerating sorbent is referred to as the regenerated fluid. Examples of heating are used as the method of sorbent regeneration, but similar methods of using vacuum pumps to lower the pressure of the process gas can also be employed as a method of sorbent regeneration. When the sorbent is regenerated by heating to release the target species in the sorbent, we will refer to the temperature used to regenerate the sorbent as a regeneration temperature. When the sorbent is capturing target species molecules from the process fluid, we will refer to the temperature of the sorbent as a capture temperature.

[0011] The target species can include but are not limited to water, carbon dioxide, and hydrogen gas. Sorbents are materials that can pick up or retain or transfer target species from a contacted process fluid through the mechanism of adsorption, absorption, or both. They can include but are not limited to porous metal-organic frameworks (MOFs), zeolites, mesoporous silica, metal oxides, carbon-based adsorbents (activated carbon, carbon nanotubes, nanofibers, graphene), biomasses, biological and organic polymers, and covalent organic frameworks (COFs). Sorbent materials are promising materials for capturing gases like carbon dioxide and water vapor from an input fluid source and collecting and concentrating them.

[0012] Porous adsorbents with high specific surface area, high adsorption capacity for the target species (carbon dioxide, water, hydrogen), low regeneration energy to release the target species, good cycle performance, and good resistance to impurities and contaminants are desirable for the successful commercial implementation. The material performance parameters for the adsorbent material are high uptake capacity and selectivity to the target species and low regeneration temperature (temperature to release most of the adsorbed target species at specific target species partial pressure).

[0013] MOFs have been proposed to work as water vapor adsorbers to capture and harvest water from the atmosphere. One such example is MOF-801 and a proposed water harvesting apparatus (US10683644B2). MOF-841, CAU-10, MOF-303, MOF-573, MOF-802, MOF-

[0014] 805, MOF-806, MOF-808, MOF-812 are other example MOFs that can be used for another water capture apparatus shown in US11779903B2. Other proposed atmospheric water harvester is in US11059838B2. Some other water vapor harvesting material are mentioned in

[0015] US application US20230321595A1. A review article on various MOFs for water harvesting are known and can be found at Adv Mater., 30(37): 61704304 (2018). Other disclosures related to building water harvesting apparatuses are found in US11384517B2 and

[0016] US11414843B2 and US11285435B2.

[0017] COF-432 is an example COF material for water adsorption (J. Am. Chem. Soc.,

[0018] 142(5): 2218-2221 (2020)). A review article on various example COFs for water harvesting can be found at Angew Chem. Int. Ed. Engl., 62(25): 6202303378 (2023) and Adv Mater.,

[0019] 35(17): 62300018 (2023).

[0020] CO2-based MOFs, such as Mg-MOF-74 (US8876953B2) and CD-MOF

[0021] (US9808788B2). COF-609 is an example COF for carbon dioxide capture (J. Am. Chem.

[0022] See., 144(28): 12989-12995 (2022)). Several example COFs for carbon dioxide capture are listed in ChemPhysChem, 24(9): 6202200808 (2023).

[0023] Summary of Invention

[0024] This and other objects have been achieved by the present invention the embodiments of which include:

[0025] A system configured to capture a target chemical species from a fluid comprising the target chemical species, comprising: at least one first sorbent that can be set to a first capture temperature and configured to receive an input fluid comprising the target chemical species; the at least one first sorbent configured to be subsequently heated to a first regeneration temperature to generate a first regenerated fluid comprising a higher target chemical species concentration or partial pressure than in the input fluid; at least one second sorbent that can be set to a second capture temperature, which may be the same or different from the first capture temperature, and configured to receive the first regenerated fluid from the at least one first sorbent to capture target chemical species from the first regenerated fluid; the at least one second sorbent is configured such that there is a nonzero mass of target chemical species transferred from the first regenerated fluid to the at least one second sorbent at the second capture temperature; and the at least one second sorbent configured to be subsequently heated to a second regeneration temperature to generate a second regenerated fluid comprising a higher target chemical species concentration or a partial pressure than the first regenerated fluid if the first regeneration temperature is equal to the second regeneration temperature.

[0026] The system above, wherein the at least one second sorbent is configured such that a mass of target chemical species transferred from the first regenerated fluid produced from the at least one first sorbent at the first regeneration temperature to the at least one second sorbent at the second capture temperature divided by a sum of a mass of target chemical species in the at least one second sorbent and a mass of target chemical species in the at least one first sorbent is greater than 0.05.

[0027] The system above, wherein at least one collector element is configured to receive the second regenerated fluid from the at least one second sorbent to concentrate, compress, condense, and / or capture the target species, or if the at least one collector element is the same as the at least one second sorbent, the at least one collector element is configured to receive the first regenerated fluid to concentrate, compress, condense, or capture the target species.

[0028] The system above, wherein one or more sorbents are connected in series after the at least one second sorbent and before at least one collector element, wherein at least one third sorbent at a third capture temperature is configured to receive the second regenerated fluid from the at least one second sorbent, and the at least one third sorbent is configured to subsequently heat at a third regeneration temperature to generate a third regenerated fluid. The system above, configured such that when a regenerated fluid produced from one sorbent at a regeneration temperature comes into contact with the next sorbent at a capture temperature, absorbed heat energy gained by the next sorbent is transferred or recycled back to a different sorbent or transferred to a thermal storage unit.

[0029] The system above, configured such that before a regenerated fluid produced from one sorbent at a regeneration temperature come into contact to the next sorbent at a capture temperature, thermal energy of the regenerated fluid is transferred or recycled back into the system or thermal storage such that a temperature of the regenerated fluid lowers towards the capture temperature of the contacted sorbent.

[0030] The system above, configured such that if the input fluid is at a higher temperature than a capture temperature of a contacted sorbent, thermal energy from a difference in an input fluid temperature and a sorbent capture temperature is transferred or recycled back to a different sorbent or transferred to a thermal storage unit.

[0031] The system above, configured such that before a regenerated fluid produced from one sorbent at a regeneration temperature comes into contact to the next sorbent at a capture temperature, the regenerated fluid contacts a heat exchanger element to lower the temperature of the regenerated fluid closer to the next sorbent capture temperature and energy transferred to the element is transferred or recycled back to another sorbent in the system or transferred to a thermal storage unit.

[0032] The system above, configured to set a temperature of one or more sorbents by flowing a heat exchange fluid comprising air or liquid that contacts passive or natural heat energy sources or heat sinks comprising ambient air, air at high elevation, underground earth, solar irradiation, waste stream byproduct from industrial processes, natural bodies of water or reservoirs. The system above, wherein the target species is water, carbon dioxide, hydrogen, nitrogen, oxygen, ammonia, methane, ethane, carbon monoxide, alcohol, sulfur dioxide, hydrogen sulfide, nitrogen oxide, or sulfur oxide.

[0033] The system above, where the input fluid is ambient air containing water and / or carbon dioxide, flue gas containing water and / or carbon dioxide, compressed air, gas containing the target species, or liquid containing the target species.

[0034] The system above, wherein a process fluid pathway can be changed based on a temperature of and a target species concentration in a process fluid such that the process fluid bypasses one or more sorbents and omits a sequential order of the one or more sorbents.

[0035] The system above, where, after the first regenerated fluid produced from the at least one first sorbent at the first regeneration temperature comes into contact with the at least one second sorbent at the second capture temperature or a collector element, the second processed fluid is redirected back to contact the at least one first sorbent.

[0036] The system above, wherein a heat exchange element transfers heat between the regenerated fluid from the at least one first sorbent at the first regeneration temperature and the processed fluid from the at least one second sorbent at the second capture temperature or a collector element at a second capture temperature, and wherein the regenerated fluid contacts the heat exchange element before contacting the second sorbent or a collector element.

[0037] A system configured to capture a target chemical species from a fluid containing said target chemical species, comprising: at least one module comprising the system of claim 1 connected to another module comprising the system of claim 1, wherein heat or pressure energy is transferred or recycled from sorbents from one module to another module; wherein a maximum operating temperature of the at least one module is lower than a minimum operating temperature the another module.

[0038] The system above, wherein collector elements in each module are connected to transfer and recycle heat or pressure energy from a collector from the at least one module to the another module.

[0039] The system above, wherein thermal energy is recycled or transferred from one sorbent to another sorbent by heat exchange through a fluid, wherein the fluid is air and liquid.

[0040] A system configured to capture target species from a fluid containing the target chemical species, comprising: at least one sorbent that can be set to a capture temperature and configured to receive an input or process fluid comprising target chemical species; the at least one sorbent configured to be subsequently heated to a regeneration temperature to generate a regenerated fluid; the at least one sorbent is set to a capture temperature by exchanging heat with one or more temperature reservoirs and / or one or more temperature control elements coupled to one or more heat exchange elements that are coupled to one or more passive or natural heat sinks; wherein the at least one sorbent is set to a higher regeneration temperature by exchanging heat with the one or more temperature reservoirs and / or the one or more temperature control elements coupled to the one or more heat exchange and / or heat collector elements that are coupled to one or more passive or natural heat energy sources; the one or more temperature control elements that manage the heat exchange or heat transfer between an exogenous heat source or heat sink and the at least one sorbent.

[0041] The system above, wherein the passive or natural heat energy sources comprises ambient air heat, solar irradiation, waste heat from industrial processes, underground earth heat, or a combination thereof. The system above, wherein the passive or natural heat sinks comprises natural bodies of water, underground earth, ambient air at low or high elevation, or a combination thereof.

[0042] The system above, further comprising a plurality of sensors to monitor an input fluid temperature and a target species concentration and adjust a process fluid path of the input fluid and regenerated fluids to contact the at least one sorbent or bypass and contact the collector element directly.

[0043] The system above, further comprising a plurality of sensors to monitor a temperature of the natural or passive heat energy sources and / or heat sinks and adjust the heat exchanged between the sorbent and the natural or passive heat energy sources and / or heat sinks.

[0044] The system above, further comprising one or more thermal storage elements that act as a temperature reservoir, set to a cold or hot temperature from exogeneous heat sources or heat sinks, which can be used to set the capture or regeneration temperature of the at least one sorbent

[0045] A method of capturing a target chemical species from a fluid containing the target chemical species, the method comprising receiving an input fluid comprising target chemical species with at least one first sorbent that can be set to a first capture temperature; heating the at least one first sorbent to a first regeneration temperature to generate a first regenerated fluid comprising a higher target chemical species concentration or partial pressure than present in the input fluid; receiving the first regenerated fluid from the at least one first sorbent to capture target chemical species from the first regenerated fluid with at least a second sorbent that can be set to a second capture temperature, which may be the same or different from the first capture temperature; wherein the at least one second sorbent is configured such that there is a nonzero mass of target chemical species transferred from the first regenerated fluid to the at least one second sorbent at the second capture temperature; and wherein the at least one second sorbent configured to subsequently heat to a second regeneration temperature to generate a second regenerated fluid comprising a higher target chemical species concentration or a partial pressure than in the at least one first regenerated fluid if the first regeneration temperature were equal to the second regeneration temperature.

[0046] The method above, wherein the at least one second sorbent is configured such that a mass of target chemical species transferred from the first regenerated fluid produced from the at least one first sorbent at the first regeneration temperature to the at least one second sorbent at the second capture temperature divided by a sum of a mass of target chemical species in the at least one second sorbent and a mass of target chemical species in the at least one first sorbent is greater than 0.05.

[0047] The method above, wherein at least one collector element receives the first regenerated fluid from the at least one second sorbent to concentrate, compress, condense, and / or capture the target species or if the at least one collector element is the same as the at least one second sorbent, the at least one collector element receives the first regenerated fluid to concentrate, compress, condense, or capture the target species.

[0048] The method above, wherein one or more sorbents are connected in series after the at least one second sorbent and before the at least one collector element, wherein at least one third sorbent at a third capture temperature is configured to receive the second regenerated fluid from the at least one second sorbent, and the at least one third sorbent is configured to subsequently heat at a third regeneration temperature to generate a third regenerated fluid.

[0049] The method above, configured such that when a regenerated fluid produced from one sorbent at a regeneration temperature comes into contact with the next sorbent at a capture temperature, absorbed heat energy gained by the next sorbent is transferred or recycled back to a different sorbent or transferred to a thermal storage unit.

[0050] The method above, configured such that before a first regenerated fluid produced from one sorbent at a regeneration temperature come into contact to the next sorbent at a capture temperature, thermal energy of the regenerated fluid is transferred or recycled back into the system or thermal storage such that a temperature of the regenerated fluid lowers towards the capture temperature of the contacted sorbent.

[0051] The method above, configured such that if the input fluid is at a higher temperature than a capture temperature of a contacted sorbent, thermal energy from a difference in an input fluid temperature and a sorbent capture temperature is transferred or recycled back to a different sorbent or transferred to a thermal storage unit.

[0052] The method above, configured such that before a regenerated fluid produced from one sorbent at a regeneration temperature comes into contact with the next sorbent at a capture temperature, the regenerated fluid contacts a heat exchanger element to lower the temperature of the regenerated fluid closer to a next sorbent capture temperature and energy transferred to the next sorbet is transferred or recycled back to another sorbent in the system or transferred to a thermal storage unit.

[0053] The method above, configured to set a temperature of one or more sorbents by flowing a heat exchange fluid, wherein the heat exchange fluid is air or liquid, that contacts passive or natural heat energy sources or heat sinks selected form the group consisting of ambient air, air at high elevation, underground earth, solar irradiation, waste stream byproduct from industrial processes, natural body of water and reservoir.

[0054] The method above, wherein the target species is water, carbon dioxide, hydrogen, nitrogen, oxygen, ammonia, methane, ethane, carbon monoxide, alcohol, sulfur dioxide, hydrogen sulfide, nitrogen oxide, or sulfur oxide. The method above, wherein the input fluid is ambient air comprising water and / or carbon dioxide, flue gas containing water and / or carbon dioxide, compressed air, gas containing the target species, or liquid containing the target species.

[0055] The method above, wherein the process fluid pathway can be changed based on the temperature of and target species concentration in a process fluid such that the process fluid can bypass one or more sorbents and omit a sequential order of the one or more sorbents.

[0056] A method to capture target species from a fluid containing said target chemical species, the method comprising: receiving an input or process fluid comprising target chemical species with at least one sorbent that can be set to a capture temperature; heating the at least one sorbent to a regeneration temperature to generate a regenerated fluid; wherein the at least one sorbent is set to a capture temperature by exchanging heat with one or more temperature reservoirs and / or one or more temperature control elements coupled to one or more heat exchange elements that are coupled to one or more passive or natural heat sinks; wherein the at least one sorbent is set to a higher regeneration temperature by exchanging heat with one or more temperature reservoirs and / or one or more temperature control elements coupled to one or more heat exchange and / or heat collector elements that are coupled to one or more passive or natural heat energy sources; wherein the one or more temperature control elements that manage the heat exchange or heat transfer between the exogenous heat source or heat sink and the at least one sorbent.

[0057] The method above, wherein the passive or natural heat energy sources comprise air heat, solar irradiation, waste heat from industrial processes, underground earth heat, or a combination thereof. The method above, wherein the passive or natural heat sinks comprise natural bodies of water, underground earth, ambient air at low or high elevation, or a combination thereof.

[0058] The method above, further comprising a plurality of sensors to monitor an input fluid temperature and a target species concentration and adjust a process fluid path of the input fluid and regenerated fluids to contact one or more sorbents or bypass and contact a collector element directly.

[0059] The method above, further comprising a plurality of sensors to monitor the temperature of the natural or passive heat energy sources and / or heat sinks and adjust the heat exchanged between the sorbent and the natural or passive heat energy sources and / or heat sinks.

[0060] The method above, further comprising one or more thermal storage elements that act as a temperature reservoir, set to a cold or hot temperature from exogeneous heat sources or heat sinks, which are capable to set the capture or regeneration temperature of the sorbent.

[0061] Description of Figures:

[0062] A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings.

[0063] Figure 1 is a plot of three sorption isotherms of water uptake versus relative humidity at different temperatures.

[0064] Figure 2 is a plot of three soiption isotherms of water uptake vs partial pressure of water vapor at different temperatures.

[0065] Figure 3 illustrates the operation of exposing a sorbent to an input fluid and regenerating the sorbent and how the uptake of the sorbent is determined by the sorption isotherms. Figure 4 is an illustration of cascading two sorbents and contains a plot of sorption isotherms for the two different sorbents.

[0066] Figure 5A is an example 2-cascaded sorbent unit.

[0067] Figure 5B is another embodiment of a 2-cascaded sorbent unit.

[0068] Figure 5C is a plot of water isotherms for sorbents in the example embodiment in

[0069] Figure SB.

[0070] Figure 6 is an example order of steps operating a cascaded sorbent unit.

[0071] Figure 7 is one embodiment of a 2-cascaded sorbent unit.

[0072] Figure 8 is an example 3-cascaded sorbent unit.

[0073] Figure 9 is a plot of sorption isotherms for two different sorbents.

[0074] Figure 10 is one embodiment of a 3-cascaded sorbent unit.

[0075] Figure 11 is an example system with 3 stages of three 2-cascaded sorbent units.

[0076] Figure 12A is one operation cycle of an embodiment of a system with 2-stages of two

[0077] 2-cascaded sorbent units.

[0078] Figure 12B is a second operation cycle of an embodiment of a system with 2-stages of two 2-cascaded sorbent units.

[0079] Figure 13 is an example order of steps operating a system with multiple stages of cascaded sorbent units.

[0080] Figure 14 is an example system with option to bypass sorbents in the fluid pathway.

[0081] Figure 15 is an example system illustrating process fluid pathway and temperaturecontrol pathway with temperature reservoir elements.

[0082] Figure 16 is an example system illustrating the temperature control management system that sets the temperatures of the sorbents and collectors by coupling to passive or natural energy sources and heat sinks. Detailed Description of Invention

[0083] All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. Further, the materials, methods, and examples are illustrative only and are not intended to be limiting, unless otherwise specified.

[0084] An object of the invention is related to cascading different sorbents where a first sorbent is first exposed to an input fluid, such as a process gas or liquid. The first sorbent captures target species molecules from the input fluid. The first sorbent is then regenerated to release the target species to a regenerated fluid that is contacted to a second, different sorbent.

[0085] The second, different sorbent captures target species molecules from the regenerated fluid produced from the first sorbent. The second sorbent is subsequently regenerated. The regenerated fluid from the second sorbent has a higher concentration of the target species than the regenerated fluid that was from the first sorbent in the prior step. This can be achieved if the sorption isotherm of the second sorbent is shifted to a higher target species concentration than the sorption isotherm of the first sorbent at the same operating temperatures of the sorbents.

[0086] These cascaded sorbents can form a unit where multiple sorbents cascade together such that a first sorbent produces a regenerated fluid that is subsequently contacted to a second sorbent that subsequently regenerates and produces a regenerated fluid that is contacted to a third sorbent and so forth. As an example, when three sorbents are used, we will call it a 3-cascaded sorbent unit, where there is a first sorbent, second sorbent, and third sorbent, where the third sorbent is the last cascaded sorbent

[0087] A cascaded sorbent unit can be designed such that the operating capture and regeneration temperatures of all the sorbents within the unit are below a certain temperature and yet can still attain a desired concentration of the target species in the regenerated fluid produced from the last sorbent that otherwise cannot be achieved from the first sorbent at that temperature. For a single sorbent, the target species concentration in the regenerated fluid is limited by the regeneration operating temperature. However, by cascading a second, different sorbent with right-shifted sorption isotherm relative to the first sorbent, the target species temperature in the regenerated fluid from the second sorbent can be increased without increasing the operation temperatures.

[0088] A cascaded sorbent unit can be further cascaded with other cascaded sorbent units to form multiple stages, where each unit is operating at capture and regeneration temperatures that are lower or higher than the other units such that energy in the form of heat or pressure can be transferred and / or recycled from one unit to another unit.

[0089] Figure 1 is an overlay of three different sorption isotherms at 25°C (11), 40°C (12), and 70°C (13) for an example sorbent. In this example, the sorption isotherm is for water uptake at different relative humidities of the immediate surrounding air (process fluid) in contact with the sorbent. Theis is not restricted to water as the target species, but for Figure

[0090] 1, water is taken as the example target species. This sorbent has low water uptake at low relative humidity between 0 to 10% for 25°C and 0 to 15% for 40°C and 70°C. However, water uptake capacity increases quickly past a threshold where it more or less plateaus. The relative humidity is temperature dependent. These plots assume isothermal condition where the sorbent and surrounding environment (process fluid) in contact with the sorbent are all at the same temperature.

[0091] Since relative humidity is dependent on temperature, a better way to compare water sorption isotherms at different temperatures is to plot x-axis as water partial pressure, where the sorbent can be at a different temperature than the surrounding environment (process fluid is a gas). Figure 2 is an overlay of the same water sorption isotherm plots shown in Figure 1, but plotted with water partial pressure on the x-axis. When the sorbent is at 25°C, the relationship describing water uptake of the sorbent at various concentrations of the target species (water partial pressure in process gas) is plotted in the water sorption isotherm 21.

[0092] According to this isotherm, the sorbent starts capturing (adsorbing) a lot more water when the surrounding environment (process gas) has water partial pressure (target species concentration in process gas) greater than approximately 0.3 kPa, indicated by point 24. The rate of water uptake versus water pressure increases dramatically as it passes point 24, and then once it reaches point 25, which is at pressure P1, the uptake capacity is at U1. As water partial pressures increases above P1, the uptake capacity increases, but not as quickly. This can be thought of as a saturation or plateau region. The depletion region can be thought of as right before the threshold when the uptake increases dramatically. The saturation region is pressures above point 25 and the depletion region as pressures below point 24 for the sorption isotherm 21. Similarly for sorption isotherm 22, the saturation region is when process fluid partial pressure is greater than the pressure at point 27 and the depletion region when partial pressure is less than the pressure at point 26. The sorption isotherms look like smooth step functions, where the threshold (or smooth transition step in the isotherm) is the point when the partial pressure (target species concentration) transitions from low uptake

[0093] (depletion region) to high uptake (saturation region).

[0094] The threshold pressure is the top or bottom of the transition region depending on if the sorbent is capturing target species (capture phase) or releasing target species (regeneration phase). If the sorbent is capturing target species at 25°C, then referencing isotherm 21, the input threshold is at point 25, which is at the top of the transition region and is the pressure when the sorbent starts enters the saturation region. If our regeneration temperature is 40°C, then referencing isotherm 22, it is the output threshold point at point 26, which is at the bottom of the transition region and is the pressure during sorbent regeneration phase when the sorbent approaches the depletion region. That higher sorbent temperatures have input and / or output threshold pressures that are shifted to higher partial pressure. The sorption isotherms 21 and 22 show uptake versus partial pressure relationship for the sorbent at 25°C and 40°C, respectively. At 40°C, isotherm plot 22 shows an input threshold at point 27, which is shifted compared to point 25.

[0095] The output threshold pressure for isotherm 22 is around point 26, which is also shifted to higher water partial pressure compared to point 24, which is output threshold for isotherm 21 at 25°C.

[0096] Without wishing to be bound by choice of the threshold value, a shift in the sorption isotherm is referred to the overall shift of the curve which can manifest as a shift in the input and / or output threshold values. In this case, sorption isotherm 22 is shifted to higher partial pressures compared to sorption isotherm 21 because threshold points 26 or 27 for isotherm 22 are shifted to higher partial pressure values than threshold points 24 or 25 for isotherm 21.

[0097] Sorption isotherm 23 can be presumed to be shifted even higher if its uptake eventually increases dramatically at higher pressures.

[0098] Figure 3 is the same example sorbent that we will call “Sorbent-A" 302 that is placed in an enclosed container 300. Continuing our example of water as the target species and the process fluid is a gaseous substance containing water vapor, the sorption isotherms 310, 311, and 312 for Sorbent-A 302 are plotted for absolute uptake vs water partial pressure of the process fluid, which occupies the space 303 inside the container 300. In this example, since sorbent-A will have a known mass in a known volume of container, one can plot the absolute uptake at different water partial pressures inside container 300. The sequence of operation is the input fluid (gas) is let inside the container 300 through a valve 301. This input fluid contacts Sorbent-A denoted by 302 where the sorbent will start capturing (or adsorbing) the target species (water) contained in input fluid, which is now the process gas. After sorbent-A captures the target species (water), if the valve 301 is closed such that sorbent-A is no longer exposed to fluids (gases) outside the container, then in order to release the target species

[0099] (water) from sorbent- A (regenerating the sorbent), the sorbent can be heated to a higher temperature through contacts A1 and A2. Without wishing to be bound by the specific example or embodiment, contacts A1 and A2 can be implemented as heat pipes or recirculation pipes where hot or cold fluid is transferred by a recirculation pump to heat and cool sorbent-A at desired temperatures. The container 300 can alternatively be connected to a vacuum pump to lower the pressure inside 300 in order for sorbent- A to release the target species (water) inside container 300. Once the target species (water) is released from the sorbent (sorbent regeneration) into the surrounding external environment 303 inside container

[0100] 300, the fluid occupying space 303 is called the regenerated fluid. This regenerated fluid can be transferred to a collector 305. This is illustrated by 304, which represents the regenerated fluid (gas) containing the target species (water) released from sorbent 302 that is transferred and contacted to a collector 305. The collector is in charge of extracting or concentrating the target species from the regenerated fluid 304. Without wishing to be bound by this specific example, for a regenerated fluid that is a gas containing water as the target species in gaseous form, the collector 305 can be implemented as a condenser at a lower temperature than the regenerated gas 304 such that the temperature of 305 is at or below the dewpoint of the regenerated gas 304 such that some of the water vapor in 304 will condense into liquid water when the regenerated gas 304 contacts the collector 305. In this example, collector 305 can be connected to Cond1 and Cond2 which can be implemented as recirculation pipes that has hot or cold liquid flowing to set the collector 305 at the desired temperature or heating elements to control temperature of 305.

[0101] Referring to the sorption isotherms, as an example, let us assume the input fluid is the ambient air at 25°C with 25% relative humidity. When sorbent-A 302 is contacted to this input gas, the container 300 will be at the input gas condition of 25°C and 25% relative humidity, which will be approximately 0.8 kPa of water partial pressure. For simplicity, we will assume this water partial pressure is equal to P1.

[0102] When the container 300 is sealed by closing valve 301, initial water partial pressure in the container is 0.8 kPa because that was the partial pressure of the input fluid. Initially, sorbent-A 302 contains U1 grams of water, but when sorbent-A 302 is regenerated at 40°C by heating through A1 and A2, it will now start to release the stored water since according to the

[0103] 40°C sorption isotherm plot 311, sorbent- A 302 at 40°C is not able to hold U1 grams of water uptake when process fluid has P1 water partial pressure. Sorbent- A 302 will release water to increase the partial pressure inside the container 300 until its absolute water uptake in the sorbent- A 302 balances with the external water partial pressure in the process fluid occupying

[0104] 303 according to the uptake vs partial pressure relationship 311. The partial pressure inside will never exceed ~2.4 kPa, which is pressure P2 indicated by point 321. Point 321 is when sorbent-A at 40°C contains U1 grams of water. Since change in temperature from 25°C to

[0105] 40°C will not increase the partial pressure past this point, volume of container 300 is not changing, container 300 is sealed, and sorbent-A cannot have an absolute water uptake more than its initial condition of U1 grams of water, when the regenerated fluid 304 is released from the container 300, it can never have a water partial pressure greater than P2. The underlying reason is that at 40°C, sorbent-A still wants to hold onto the water for pressures as low as P2.

[0106] There are various reasons why one would want the partial pressure built up in container 300 to exceed a minimum value, including but not limited to, meeting a certain dew point value to begin condensing water. In this case, if our collector 305 is a condenser, then when it contacts the regenerated fluid 304, one would want water to start condensing at a given temperature of condenser 305. Another reason could be to concentrate the regenerated fluid higher for downstream processing. In one particular example, if we have a condenser as collector 305 running at 25°C trying to condense water from regenerated fluid 304, water will never condense because 304 can never reach the dew point pressure ~3.2 kPa because at this pressure sorbent- A 302 at

[0107] 40°C can never go higher than ~2.4 kPa (around point 321) as explained above. In order for

[0108] Sorbent-A 302 to release more of its captured (adsorbed) water to increase the water partial pressure in 303, Sorbent-A 302 will have to be heated to a higher temperature. For example, when heated to 70°C, where at P3 ~ 3.2 kPa, sorbent-A 302 only has an uptake much less than U1 grams of water (point 322). Therefore, regenerated fluid 304 can attain higher water partial pressures greater than 3.2 kPa.

[0109] It is one aspect of this invention to attain higher target species concentration in the regenerated fluid 304 without having to resort to increasing operating temperature of sorbent.

[0110] This can be accomplished by employing a second, different sorbent-B with shifted sorption isotherm relative to the first sorbent-A. Figure 4 plots the sorption isotherms at given chamber 400 volume and mass for first Sorbent-A (401) and second Sorbent-B (402) at different temperatures. Sorption isotherm plots 410 and 411 are for first Sorbent-A (401) at temperatures 25°C and 40°C, respectively. Sorption isotherm plots 412 and 413 are for second Sorbent-B (402) at temperatures 25°C and 40°C, respectively. At a capture temperature (25°C in this example), first Sorbent-A 401 captures U1 grams of target species when target species partial pressure in process fluid is P1 (point 420). At a regeneration temperature (40°C in this example), first Sorbent-A 401 will retain a maximum U1 grams of target species at target species partial pressure P4 > P1 (point 421). Second Sorbent-B 402 has shifted 40°C sorption isotherm 413 compared to first Sorbent-A 40°C sorption isotherm

[0111] 411 so that at the same regeneration temperature 40°C, second Sorbent-B 402 will only capture U1 grams of target species when partial pressure in process fluid is greater than P5

[0112] (point 422). For first Sorbent-A 401 with a given uptake of U1 grams, the maximum target species partial pressure in the regenerated fluid (released or desorbed fluid from sorbent-A) at

[0113] 40°C regeneration temperature will be P4. While on the other hand, by first transferring U1 grams of target species to a second, different sorbent-B 402 and then releasing target species from this same sorbent-B, the maximum target species partial pressure in the regenerated fluid (released or desorbed fluid from sorbent-B) at the same chosen regeneration temperature is now P5 > P4.

[0114] An advantage of this invention is effectively expanding the distance along x-axis

[0115] (partial pressure) between the sorption isotherms by using a first sorbent for capturing target species from an input fluid and using a different, second sorbent with shifted sorption isotherm for producing regenerated fluid at higher target species partial pressure. First

[0116] Sorbent-A can be chosen because it can adsorb water at low partial pressures. However, first

[0117] Sorbent-A may not desorb enough at a desired regeneration temperature, in this case 40°C.

[0118] This may be material limited since this material has a strong affinity to the target species and would need higher regeneration temperatures to release it. However, another second Sorbent-

[0119] B can desorb much more at 40°C, but at 25°C, it isn’t able to capture as much target species below a certain partial pressure from an input fluid. In this example, perhaps one would want to capture U1 grams at P1 pressure at 25°C, but using sorbent-B alone can only capture much less at P1 at 25°C (shown at point 423). The amount of target species captured at point 423 is much less than point 420. Therefore, employing two different sorbents such that first sorbent can capture at lower partial pressures, but since it cannot produce a regenerated fluid

[0120] (released or desorbed fluid) at a regeneration temperature with high enough concentration of target species, it first releases its target species to a second sorbent-B, that can subsequently produce a regenerated fluid (released or desorbed fluid) with higher target species concentration even at the same regeneration temperature of the first sorbent. Therefore, the operating temperatures can be kept low or the same whilst still producing higher target species partial pressures.

[0121] The operational sequence of capturing target species from process fluid to first sorbent and producing regenerated fluid in first sorbent that contacts second sorbent to transfer target species from first sorbent to second sorbent is referred to as cascading first sorbent to second sorbent.

[0122] It is one of the key aspects of this invention of having the capability to restrict the operating temperatures of the sorbents and yet still have the ability to capture low target species concentration and produce a final regenerated fluid output with high target species concentration. With only one sorbent, the only way to capture low target species concentration and generate a fluid with high target species concentration is to increase the regeneration temperature of the sorbent. In other words, the target species concentration range (target species concentration in regenerated fluid subtracted from target species concentration in input fluid of a single sorbent) is directly tied to the temperature range

[0123] (regeneration temperature subtracted by capture temperature of a single sorbent). However, this invention can increase the target species concentration in the regenerated fluid output of the last sorbent in the cascaded sequence. This invention decouples the operating temperature range and target species concentration range such that even with fixed operating temperature range, the target species concentration range can increase by simply adding another sorbent

[0124] (with shifted sorption isotherm) in the cascade sequence.

[0125] The invention relates to the design of the sorbents in a cascaded unit such that the different sorbents that are cascaded together have shifted sorption isotherms, where the second sorbent is shifted to higher partial pressures or concentrations compared to the first sorbent so that when the first sorbent produces a regenerated fluid that is contacted to the second sorbent at a capture temperature, the second sorbent can capture the target species from the regenerated fluid generated by the first sorbent and subsequently produce a regenerated fluid at a regeneration temperature that has higher target species concentration than could not otherwise be produced from the first sorbent at the same regeneration temperature.

[0126] Two conditions to design the cascaded sorbent system are to enable the transfer of the target species from the first sorbent to the second sorbent and to produce a regenerated fluid with higher concentration of target species from the second sorbent than the first sorbent at the same regeneration temperatures.

[0127] To illustrate the first condition of transferring target species from first sorbent to second sorbent, imagine we have both first sorbent-A (401) and second sorbent-B (402) inside a container 400, where there is an internal space 403 inside the container 400 but external to the sorbents 401 and 402 and is occupied by the regenerated fluid produced from sorbent-A 401. Suppose the initial condition is that the first sorbent 401 has captured U1 grams of target species and the partial pressure is P1 in process fluid occupying 403. The initial condition also assumes second sorbent has no uptake. Now suppose we heat up first sorbent 401 to a regeneration temperature and maintain the second sorbent 402 at a capture temperature. In this example, the regeneration and capture temperature are set at 40°C and

[0128] 25°C, respectively. The 1 transfer cycle is complete when an equilibrium condition for the target species concentrations in the first sorbent, second sorbent, and in process fluid occupying 403 is reached. The first sorbent is regenerating at a regeneration temperature to release its target species into the process fluid in 403 and second sorbent is set at a capture temperature to capture the target species from this same process fluid. Following the sorption isotherms shown in Figure 4, assuming second sorbent 402 is not present (single sorbent system) and volume occupied by the fluid in 403 is unchanged (i.e., decrease size of container 400 by volume of second sorbent 402), then when first sorbent 402 is regenerated, it will release some of the target species and end up with an uptake of U2 grams at some pressure P3 (point 424). However, if we add a second sorbent 402, the uptake in first sorbent

[0129] 401 will be lower at U4 grams (point 426) and uptake in second sorbent 402 will be U3 grams (point 425). The amount of target species transferred to second sorbent is U3 grams while U4 grams are in the first sorbent. According to conservation of mass of the target species, U3 plus U4 plus mass of target species in process fluid at pressure P2 is equal to U2 plus mass of target species in process fluid at pressure P3 which is also equal to U1 plus mass of target species in process fluid at pressure P1. The transfer ratio is a mass of target species transferred to second sorbent over the sum of mass of target species in the first sorbent and mass of target species in the second sorbent. In this example, the transfer ratio will be U3 divided by sum of U3 and U4. If the second sorbent isotherm at capture temperature 25°C is matched to first sorbent isotherm at regeneration temperature 40°C (i.e., sorption isotherms

[0130] 411 and 412 overlap exactly), then the mass of target species in first and second sorbents will be the same and the transfer ratio will be equal to one half. Ideally, we would want the transfer ratio to be 1, which would indicate maximum transfer of target species from first sorbent to second sorbent per cycle. Therefore, the capture isotherm for the second sorbent should not be shifted to the right (towards higher partial pressures) too much such that the transfer ratio is much less than 1. This can occur if one chooses a second sorbent with only one concern to maximize the target species concentration in the regenerated fluid of the second sorbent (large right-shift for regeneration temperature isotherm for second sorbent which usually will also have large right-shift for capture temperature isotherm as well). If there is no target species capture onto the second sorbent at some capture temperature when first sorbent is at some regeneration temperature, then transfer ratio is zero.

[0131] Therefore, for a cascaded sorbent unit with first sorbent and second sorbent, we capture the target species from an input fluid onto the first sorbent where first sorbent is at capture temperature TC1. The 1 cycle is the first regenerating of the first sorbent at regeneration temperature TR1 to produce a regenerated fluid. The second sorbent is at capture temperature TC2 to transfer target species from this regenerated fluid to second sorbent. If equilibrium were allowed to be reached, then that would complete a theoretical single cycle of transferring target species from first sorbent to second sorbent. The first design includes, for example, the transfer ratio (with first sorbent at temperature TR1 and second sorbent at temperature TC2) is greater than zero and ideally as close to 1 as possible.

[0132] If target species mass in first sorbent is ten times target species mass in second sorbent, then transfer ratio is approximately 0.91. The lower the transfer ratio, the more cycles can be performed to regenerate the first sorbent at TR1 and capture onto second sorbent at temperature TC2 in order to transfer all of the initial target species from first sorbent to second sorbent. For a transfer ratio of 1, all of the target species is released from first sorbent and into regenerated fluid and second sorbent in 1 cycle.

[0133] After the transfer of some or all of the target species from the first sorbent to the second sorbent, the second sorbent is regenerated at temperature TR2. The second design requirement is the target species concentration in the regenerated fluid produced from second sorbent at temperature TR2 should be greater than the regenerated fluid produced from the first sorbent at the same temperature TR2; otherwise, there would be no need to transfer target species to a second sorbent if the regenerated fluid from the first sorbent would produce higher target species concentration than the regenerated fluid produced from the second sorbent.

[0134] Although Figure 4 shows sorption isotherms for water uptake of a sorbent versus water partial pressure, the invention is related to general sorption isotherms for other target species, including but not limited to carbon dioxide or hydrogen gas versus carbon dioxide or hydrogen gas partial pressures. If the process fluid is a liquid, then the x-axis will be concentration of the target species in the liquid. Throughout this invention disclosure, examples using water uptake vs water partial pressure can be also applied for the other target species molecules. Examples of gas process fluid is also applicable to liquid process fluid.

[0135] Figure 5A is an embodiment of the invention where we have an input fluid 500 that enters into chamber 510 that is made up of an enclosed process fluid 512 contacting and external to sorbent-A 511 but internal to chamber 510. Without wishing to be bound by specific implementation, the sorbent-A 511 can be heated through A1 and A2 either through electrical heating or by flowing a heating / coolant fluid. After the first sorbent- A 511 captures

[0136] (or adsorbs) the target species (adsorbate) from input fluid 500, where first sorbent-A is at capture temperature TC1, the chamber 510 is sealed from input fluid 500 and output fluid path 501. First sorbent-A is then regenerated at regeneration temperature TR1 to release (or desorb) the target species to create a more concentrated regenerated fluid 512. This regenerated fluid 512 is then transferred as an output fluid 501 and into chamber 520 to enter the internal volume that is external to sorbent-B 521 but internal to container 520. The process fluid occupying space 522 is now comprised of output fluid 501 and possibly mixed with some of the previous fluid occupying the container 520. The target species in process fluid 522 is then adsorbed to second sorbent-B 521 that is at some capture temperature TC2.

[0137] Then, chamber 520 is sealed from fluid path 501 and fluid path 502, and then second sorbent-

[0138] B 511 is regenerated at a regeneration temperature TR2 to concentrate the target species at a higher concentration than what it was in chamber 510. The higher concentrated regenerated fluid that is now 522 is then transferred to a subsequent chamber 530, which may comprise of another third sorbent or a collector, including but not limited to another sorbent for further adsorption, or a collector to do compression, concentration, or condensation of the target species. In this example, since we are cascading two sorbents, first sorbent-A 511 and second sorbent-B 521, they form a 2-cascaded system design. After the second chamber 520, the 522 fluid is transferred as output fluid 502 and into chamber 530 that will collect the target species into another form. For the case of water, it can be condensed to liquid water. The purpose to cascade the first sorbent 511 (sorbent-A) and second sorbent 521 (sorbent-B) is to increase the concentration of the target species to collect, compress, concentrate, or condense it easier in chamber 530.

[0139] It is another embodiment of this invention that since the regenerated fluid from first sorbent-A 511 is typically at higher temperature TR1 than the capture temperature TC2 of the second sorbent-B 521, the temperature of second sorbent-B 521 will increase as it is contacted by the regenerated fluid coming from 512 and hence this extra heat absorbed and gained on second sorbent-B 521 can be recycled and transferred back to first sorbent-A 511 if first sorbent-A 511 is still regenerating at temperature TR1 or alternatively, transferred and stored in an external thermal storage.

[0140] Since the regenerated fluid from first sorbent-A 511 can be at higher temperature TR1 than the temperature TC2 of the second sorbent-B 521 that it contacts, the temperature of the surface of second sorbent-B 521 that is in immediate contact with the regenerated fluid will be somewhere in between TR1 and TC2. If TR1 is very high compared to TC2 to increase the surface temperature of second sorbent-B 521, it could inadvertently start making the surface layer of second sorbent-B 521 desorb (regenerate) the target species instead of adsorbing

[0141] (capturing) it. In this case, it is another embodiment of this invention that if we want to ensure second sorbent-B 521 temperature is as close to TC2 as possible, we can add an optional element in the fluid path of 501 such that before the regenerated fluid from first sorbent-A 511 contacts second sorbent-B 521, the regenerated fluid from 512 can go through this element, including but not limited to, e.g., a heat exchanger, heat pipe, to lower the temperature from TR1 to TC2 such that when the regenerated fluid contacts second sorbent-B

[0142] 521 that is maintained at TC2 through B1 / B2, there will be minimal temperature increase for this second sorbent-B 521. Therefore, an embodiment of this invention is to add an element such that before the regenerated fluid from first sorbent contacts second sorbent, the regenerated fluid contacts this element, including but not limited to, e.g., a heat exchanger, heat pipe, that will lower the temperature of the regenerated fluid. The heat that is transferred from the regenerated fluid to this element can be taken to thermal storage or recycled back into the system.

[0143] For simplicity, we label the transfer characteristics with the input and output threshold pressures for adsorption and desorption for sorbents 511 and 521, where the input threshold pressure is the pressure when the uptake nears saturation at a capture (or adsorption) temperature and the output threshold pressure as the uptake nears depletion at a regeneration

[0144] (or desorption temperature). In other words, input threshold pressure is at the top of the transition region and output threshold pressure is at the bottom of the transition region. In this example, the capture and regeneration temperatures are 25°C and 40°C, respectively, and the same for both sorbents. Temperatures TC1 = TC2 = 25°C and TR1 = TR2 = 40°C.

[0145] Referencing Figure 4 for first sorbent-A and second sorbent-B sorption isotherms, for first sorbent-A at 25°C (capture temperature TC1), uptake is approaching saturation at around 0.8 kPa on isotherm 410 and at 40°C (regeneration temperature TR1), first sorbent-A is approaching depletion at around 1.4 kPa according to isotherm 411. This means that during adsorption for first Sorbent-A at 25°C, it can have uptake close to full capacity even when partial pressure is as low as 0.8 kPa and during desorption for first sorbent-A at 40°C, it is close to full depletion when external partial pressure is as high as 1.4 kPa. In other words, first Sorbent-A can be exposed to as low as 0.8 kPa of water partial pressure and be adsorbed to almost max capacity and during regeneration at 40°C, external water partial pressure can be as high as 1.4 kPa after almost releasing all its stored water (almost fully depleted).

[0146] However, releasing all its stored water and only able to concentrate external partial pressure up to 1.4 kPa may be insufficient, and hence, we transfer this 1.4 kPa partial pressure regenerated fluid to the subsequent chamber 520. In chamber 520, the process fluid 522 is now at 1.4 kPa and contacting second sorbent-B 521 at 25°C (capture temperature TC2). The regenerated fluid with 1.4 kPa water partial pressure is greater than second sorbent-B 521 input threshold pressure of 1.3 kPa according to isotherm 412. After second sorbent-B 521 adsorbs the water, we effectively transferred the water from first sorbent-A 511 to second sorbent-B 521. Sorbent-B 521 can then switch to regeneration and be almost fully depleted with regenerated fluid containing partial pressure as high as 3.6kPa according to isotherm

[0147] 413. This means during desorption, the regenerated fluid 522 can be as high as 3.6 kPa and second sorbent-B 521 can still be almost fully desorbed and emptied. Therefore, we have effectively increased the water partial pressure from 1.4 kPa to 3.6 kPa by cascading first sorbent-A 511 with second sorbent-B 521 to generate regenerated fluid with water partial pressure of 3.6 kPa, which is high enough to condense water vapor at 25°C. Therefore, if we add a condenser at 25°C in chamber 530, it will condense the water vapor in the process fluid

[0148] 502.

[0149] Figure 5B is an example embodiment of Figure 5A where the first sorbent-A (511) is selected to be the metal-organic framework (MOF) MOF-303 [ A1(OH)(PZDC), PZDC = 1H- pyrazole-3,5-dicarboxylate ] and second sorbent-B (521) is selected to be MIL-100(Fe) [

[0150] Fe3O(H2O)2OH(BTC)2, BTC = benzene-l,3,5-tricarboxylate ]. Chambers 510 and 520 in

[0151] Figure 5A are chambers 510a and 520a in Figure 5B, respectively. Chamber 510a has various valves 540, 541, 543, and 542 to control the flow of the process, processed, and / or regenerated fluids, where the valves can include but not limited to gate valves, globe valves, ball valves, butterfly valves, check valves, needle valve, and sliding door to maximize crosssectional area for fluid flow, pneumatically or electrically controlled. In this example, the sorbents capture water from air. Figure 5C shows the isotherm plots at different temperatures. The isotherms show the relationship between the water uptake of MOF-303 and MIL-100(Fe) versus water partial pressure in the process or regenerated fluid contacting the MOF. The input process fluid 500a can be ambient air that passes through a fen 560 to speed up the intake air velocity. The intake is through valve 540 and after the ambient air

[0152] (input process fluid) contacts the MOF-303 first sorbent, the air (processed fluid) leaves chamber 510a through an exhaust valve 541. The MOF-303 first sorbent will capture water from the intake air stream 500a during this adsorption cycle while being kept at a capture temperature. Since water is captured from the input process fluid, the processed fluid exiting through valve 541 is less humid than the ambient air process fluid entering through valve

[0153] 540. The temperature of the MOF-303 is maintained by the heat exchange element 550, which can be a circulating thermal fluid, which is water in this example, that passes through an external heat exchanger that exchanges heat with an external source that can be at the capture temperature or regeneration temperature, which in this example, are 25°C and 45°C, respectively. The capture and regeneration temperatures do not have to be the same for the first and second MOF sorbents. When MOF-303 goes through the desorption cycle, valves

[0154] 540 and 541 will be closed, and valve 542 and 543 are opened. During the desorption cycle, the MOF-303 sorbent is then heated to 45°C through heat exchange element 550 to desorb the water that had been adsorbed from the input air stream during the previous adsorption cycle. The second sorbent MIL-100(Fe) will be in the adsorption cycle and will be set to a capture temperature, which is 25°C in this example. When the second sorbent MIL-100(Fe) is ready to capture the water from the regenerated fluid of MOF-303, valves 544 and 545 are opened. The path 501a and 501b is the circulating pathway for the regenerated fluid of first sorbent MOF-303 in chamber 510a to flow and contact the second sorbent MIL-100(Fe) in chamber 520a and this processed fluid of second sorbent MIL-100(Fe) circulates back to contact first sorbent MOF-303. The air (regenerated fluid) in chamber 510a becomes more humid due to the desorption of the first sorbent MOF-303 and leaves chamber 510a and goes into chamber 520a to contact the second sorbent MIL- 100 (Fe). After contacting the second sorbent MIL-100(Fe), the air (processed fluid) becomes less humid as the water leaves the air and adsorbs onto the second sorbent. The air stream exits chamber 520a through valve 545 and enters back into chamber 510a through valve 543 to contact the first sorbent MOF-303 again, at which point it becomes more humid again as water that is desorbing from the first sorbent MOF-303 enters the air in chamber 510a. The circulating air is the carrier gas that transfers the captured water in first sorbent MOF-303 to the second sorbent MIL-100(Fe).

[0155] Captured water in first sorbent is desorbing from the first sorbent that is at a regeneration temperature, goes into the circulating carrier gas, and then leaves the carrier gas and adsorbs onto the second sorbent that is at a capture temperature. Since the first sorbent MOF-303 can be at a higher regeneration temperature than the second sorbent MIL-100(Fe) that is at a lower capture temperature, the temperature of the circulating carrier gas can be higher in the

[0156] 501a path than in the return path 501b. In this example, a fan is added to help set the recirculating gas flow rate. This embodiment adds a heat exchanger 552 that exchanges the heat between the air (regenerated fluid from MOF-303) exiting chamber 510a flowing in path

[0157] 501a and the air (processed fluid from MIL-100(Fe) ) exiting chamber 520a flowing in path

[0158] 501b. After a set transfer time when the desired amount of water is transferred from first sorbent to second sorbent, the first chamber 510a can go back into an adsorption cycle and the second chamber 520a can go into a desorption cycle. Valves 540 and 541 are opened again to let ambient air (input process fluid) enter chamber 510a again to contact the MOF-

[0159] 303 and the processed fluid exits through valve 541. Valves 542 and 543 are closed to seal off chamber 510a from chamber 520a. The first sorbent MOF-303 is set to the capture temperature to adsorb water from the input stream of ambient air 500a. Second sorbent MIL-

[0160] 100(Fe) will be set to the regeneration temperature to desorb the water it captured from its previous adsorption cycle. Valves 544 and 545 are closed and valves 546 and 547 are opened.

[0161] The regenerated fluid generated in chamber 520a will enter the condensation chamber 530a by opening valves 548 and 549. There is a recirculating air flow path where humid air (the regenerated fluid from MIL-100(Fe) second sorbent) exits chamber 520a, flows through path

[0162] 502a, contacts the condensing element 551 to condense water from the circulating air, circulates back through path 502b, and flows back into chamber 520a to contact second sorbent MIL-100(Fe) again. The circulating air becomes more humid from water desorbing from the second sorbent MIL-100(Fe). It is another embodiment of this invention to add a similar air-to-air heat exchanger like 552 to exchange the heat between the air exiting chamber 520a flowing through path 502a and the air exiting the condensation chamber 530a flowing through path 502b. The condensing surfaces in condensation chamber 530a are maintained at a low condensation temperature by a recirculating thermal fluid flowing through 551 that exchanges heat with an external source that is set to the condensation temperature, which is 25°C in this example.

[0163] Referring to the example operation described for Figure 5B and the isotherms in

[0164] Figure 5C, if the ambient air intake is around 25°C and 50% relative humidity (RH), the water partial pressure will be about 15.9 mbar and if MOF-303 is set to a capture temperature of 25°C, the maximum uptake in MOF-303 will be about 0.4 g / g. Without wishing to be bound by theory, assuming the same mass for both MOF-303 and MIL-100(Fe), MOF-303 has maximum uptake of 0.4 g / g, MIL-100(Fe) almost has no water uptake, ignoring the effect of volume of chambers, and if MOF-303 is heated to a 45°C regeneration temperature and

[0165] MIL-100(Fe) is at a 25°C capture temperature, then water partial pressure may settle at around lOmbar where the first sorbent MOF-303 may reduce its water uptake down to 0.1 g / g, while the second sorbent MIL-100(Fe) may capture the water from the regenerated fluid of MOF-303 to adsorb water to about 0.3 g / g. After transferring water from first sorbent MOF-303 to second sorbent MIL-100(Fe), the MIL-100(Fe) desorbs water at regeneration temperature 45°C. If the condensation chamber is set to condensation temperature 25°C, then the water saturation vapor pressure will be about 31.7mbar. Without wishing to be bound by theory, according to the MIL-100(Fe) isotherm at 45°C, the MIL-100(Fe) may desorb its water and lower its water uptake down to about 0.2 g / g. Therefore, a 0.1 gram of water per gram of MIL-100(Fe) can release from the desorbing MIL-100(Fe) and condense at 25°C in the condensation chamber. Therefore, in this example embodiment in Figure 5B with MOF-

[0166] 303 and MIL-100(Fe) as the first sorbent and second sorbent, respectively, and regeneration, capture, and condensation temperatures are chosen to be 45°C, 25°C, and 25°C, respectively, and first and second sorbents have the same mass, then it is possible to condense 0.1 grams of water per gram of MIL-100(Fe) after every cycle, where a cycle comprises: first an adsorption cycle for first sorbent MOF-303 to capture water from ambient air, followed by a desorption cycle for this first sorbent MOF-303 coupled to an adsorption cycle for second sorbent MIL-100(Fe) to transfer water from MOF-303 to MIL-100(Fe), and lastly, followed by a desorption cycle for second sorbent MIL-100(Fe) to transfer water from MIL-100(Fe) to the condensation chamber 530a to condense water.

[0167] Figure 6 is the operational steps for an n-cascaded system design. The discussion of operation in Figure 5A is for n=2 (2-cascaded system). The input fluid containing the target species contacts the first sorbent at some capture temperature TC1 (step 610). After the first sorbent captures the target species from the input fluid, it is regenerated at regeneration temperature TR1 > TC1 to produce a regenerated fluid that will contain target species released from the first sorbent (step 620). The regenerated fluid is transferred and contacted to a second sorbent whose temperature is at capture temperature TC2 (step 630). After the second sorbent captures the target species from the regenerated fluid, it is then also regenerated at regeneration temperature TR2 > TC2 (step 640). The regenerated fluid coming out of the second sorbent in step 640 should contain a higher concentration of target species than the regenerated fluid that came out of the first sorbent in step 620. For a 2 -cascaded sorbent design, the regenerated fluid of the second sorbent is then transferred to a collector to collect the target species from the regenerated fluid (step 660). For n>2, operational steps 630 and 640 are repeated as described in operational step 650. The regenerated fluid from second sorbent is contacted to the third sorbent, which is then subsequently regenerated to produce a regenerated fluid that is then contacted to a fourth sorbent and so on until the last nth sorbent.

[0168] The last, nth sorbent is regenerated to produce a regenerated fluid that is contacted to a collector (step 660).

[0169] Figure 7 is an embodiment of Figure 5A where the two cascaded chambers for sorbent-A (701) and sorbent-B (705) are separated by a wall 703 and the regenerated fluid from sorbent-A can transfer to contact sorbent-B through a flow valve 704. The flow valve

[0170] 720 is to let in an input fluid to contact sorbent-A. In the various embodiments, we mention flow valves, but these can either be a slide valve, gate valve, or any type of valve or element that can control the time and / or flow when a fluid from one area or chamber is let into or transferred to another area or chamber.

[0171] For simplicity, we assume the volume 702 is same as volume 403 and the mass and sorbent for 701 are the same as the mass and sorbent for 401. Similar, we assume we are using the same mass and sorbent for 402 and the mass and sorbent for 705. This means we can reuse the example sorption isotherms in Figure 4 for the discussion of Figure 7. Similar to Figure 5A, we can label the sorbents with transfer characteristics of their input and output threshold pressures. The input and output threshold pressures indicate pressures the sorbents are close to saturation or depletion when they are operating at capture or regeneration temperatures, respectively. For sorbent-B 705, when it is at capture temperature 25°C, it is in saturation with process fluid target species pressures as low as 1.3 kPa (input threshold pressure of sorbent-B 705). Sorbent-B 705 at regeneration temperature 40°C can release most of its target species in its depletion region and produce a regenerated fluid with target species pressure as high as 3.6 kPa (output threshold pressure of sorbent-B 705).

[0172] Following the operational steps highlighted in Figure 6 and the sorption isotherms for sorbent-A and sorbent-B in Figure 4, we first contact the input fluid to sorbent-A 701 by opening up flow valve 720. If sorbent- A 701 is set to 25°C through A1 and A2 to capture the target species from the input fluid now occupying internal space 702, then we follow sorption isotherm 410 from Figure 4. In order for Sorbent-A 701 to capture the target species in its saturation region, we will use an input fluid containing the target species at partial pressure greater than 0.8 kPa (P1 in Figure 4). This maximizes the use of sorbent-A because sorbent-

[0173] A can adsorb the target species to its saturation region. This is the first operational step 610 in

[0174] Figure 6. After Sorbent-A captures the target species in its saturation region, the flow valve

[0175] 720 is sealed and then if sorbent-A 701 is regenerated at 40°C by A1 and A2, the partial pressure of the target species of the regenerated fluid will occupy chamber 702 (when flow valves 720 and 704 are sealed). This is operational step 620 in Figure 6. The partial pressure of the target species in the regenerated fluid will increase from the initial condition 0.8 kPa

[0176] (P1 in Figure 4) set by the input fluid. Sorbent-A will release some of its captured target species into the regenerated fluid in chamber 702, which will increase the partial pressure of the target species inside the regenerated fluid. The size of the chamber 702 and the mass of

[0177] Sorbent-A 701 will determine the final partial pressure built up inside 702, but for our example, this mass vs partial pressure relation is described in the sorption isotherm 411 in

[0178] Figure 4. The partial pressure will increase from 0.8 kPa but no more than approximately 2.4

[0179] Kpa (P3 in Figure 4). Taking water as an example target species, this isn’t enough to condense the regenerated fluid at 25°C. Therefore, this invention resolves this by employing a cascaded Sorbent-B 705. The regenerated fluid from sorbent-A 701 is transferred through valve 704 to contact sorbent-B 705 inside chamber 706. This is the operational step 630 in

[0180] Figure 6. Sorbent-B now captures the target species from the regenerated fluid of sorbent- A

[0181] 701, where sorbent-B 705 can be maintained at 25°C through B1 and B2. According to sorption isotherms 411 and 412, sorbent- A 701 can release most of its captured target species down to its depletion region and sorbent-B 705 can recapture the target species up to its saturation region. This cross over is around pressure P2 to P3. After most of the target species is transferred from sorbent-A to sorbent-B, valves 704 and 708 can be closed and sorbent-B

[0182] 705 can then be regenerated at a regeneration temperature (40°C for this example) through B1 and B2. This is operational step 640 in Figure 6. According to sorption isotherm 413, sorbent-B 705 can release most of its captured target species down to its depletion region and produce a regenerated fluid inside chamber 706 that can go as high as 3.6 kPa partial pressure of the target species. If the target species is water, this partial pressure is enough to condense water at 25°C. Therefore, the next operational step 650 in Figure 6 will contact the regenerated fluid from sorbent-B 705 to a collector, in this case a condenser 709, by opening up flow valve 708. The regenerated fluid from sorbent-B 705 that was in chamber 706 will contact the collector, which in this embodiment, is a condenser 709 that is kept at 25°C through Cond1 and Cond2.

[0183] Continuing with using water as an example for the target species, if we want to design a water harvester that can capture water from the air and condense to liquid water in some desert conditions, where night time conditions can be 7°C and 20% RH (~ 0.2 kPa water partial pressure), then one can choose first Sorbent-A with 7°C sorption isotherm that has a saturation region at water partial pressures > 0.2 kPa. If we wanted to design the system to regenerate first sofbent-A at 40°C, then if the sorption isotherm for sorbent-A at 40°C doesn’t produce a regenerated fluid with high enough partial pressure to condense water at a desired condenser temperature, then this invention would cascade one or more subsequent sorbents such that the regenerated fluid produced from the last sorbent can have a partial pressure high enough to condense at that desired condenser temperature. Cascading multiple Sorbents help concentrate / increase water partial pressure of the regenerated gas whose dew point will at least be higher than the desired temperature the condenser (collector) is chosen to operate at.

[0184] In the previous example of Figure 7, the condenser was chosen to operate at 25°C, so we cascaded two sorbents in order for the regenerated gas produced from the second sorbent will have a dew point of at least 25°C.

[0185] Figure 8 is a block diagram for a 3-cascaded sorbent system design. It is similar to

[0186] Figure 5A, except now we have a third sorbent. It will also follow similar operational steps in Figure 6, except now there is a third sorbent that will capture the regenerated fluid from the second sorbent and then regenerate to produce a regenerated fluid that will then transfer and contact the collector at the end. In Figure 8, the input fluid is 810 that contacts a first sorbent 801. After the first sorbent, at a capture temperature, captures the target species from the input fluid, it is regenerated at a regeneration temperature to produce a regenerated fluid

[0187] 811 that transfers to and contacts a second sorbent 802. After the second sorbent captures the target species from the regenerated fluid 811, it is then regenerated to produce a regenerated fluid 812 that is then transferred and contacted to a third sorbent 803. After the third sorbent captures the target species from the regenerated fluid 812, it is regenerated to produce a regenerated fluid 813 that is transferred and contacted to a collector 804. This collector can either be a condenser, compressor, or final sorbent

[0188] Figure 9 plots the sorption isotherms for given mass and chamber volumes for hypothetical examples Sorbent-B and sorbent-C at different temperatures. We take the same sorption isotherm curves 412 and 413 of Sorbent-B from Figure 4 and re-plot as 910 and 920 in Figure 9. Sorbent-B sorption isotherms at 25°C and 40°C are 910 and 920, respectively.

[0189] Sorbent-C sorption isotherms at 25°C and 40°C are 930 and 940, respectively. Again the input threshold pressure is the pressure when the uptake nears saturation at a capture temperature and the output threshold pressure is when the uptake nears depletion at a regeneration temperature. If we take capture temperature to be 25°C and regeneration temperature as 40°C, then the input threshold pressures for sorbent-B and sorbent-C are located around points 901 and 903, respectively. The output threshold pressures for sorbent-B and sorbent-C are located around points 902 and 904, respectively. In a 3-cascaded sorbent system design, we take the third sorbent-C to have sorption isotherm curves that are shifted to higher partial pressures relative to sofbent-B. Sometimes cascading two sorbents is insufficient to increase the target species partial pressure high enough for an application, so a third can be added. For water as target species, a higher water partial pressure at the last stage means you can condense the water vapor at higher condenser temperature.

[0190] Figure 10 is an embodiment employing the 3-cascaded sorbent system design. In this hypothetical example, Sorbent-A, Sorbent-B, and Sorbent-C have sorption isotherms shown in Figure 4 and Figure 9. Similar to Figure 5A and Figure 7, for simplicity, we denote the transfer characteristics of each Sorbent with an input threshold pressure at capture temperature 25°C and output threshold pressure at a regeneration temperature 40°C. This is an example where with a third cascaded Sorbent-C, the output pressure is further increased from 3.6 kPa to 4.6 kPa. A higher concentration water vapor of 4.6 kPa pressure gas coming from chamber 1010 is more than enough to condense a water vapor to liquid water with a condenser 1013 at a higher 30°C temperature if desired. The sequence of operational steps will be similar to that outlined in Figure 6, except there are additional steps for the third sorbent-C 1009, where we contact the regenerated fluid in chamber 1006 to sorbent-C 1009 at a capture temperature 25°C followed by regenerating the sorbent-C 1009 at release temperature 40°C and this regenerated fluid that comes from sorbent-C 1009 is taken to the collector 1013. In this case, the collector is a condenser 1013. Similar to the embodiment shown in Figure 7 for a 2-cascaded sorbent system design, this 3-cascaded sorbent system design has a valve 1020 that let’s the input fluid in to contact the first sorbent- A 1001 at its operating capture temperature. Then we have valves 1004, 1008, and 1012 that transfers regenerated fluids in chambers 1002, 1006, and 1010 to the adjacent chambers 1006, 1010, and 1014, to contact the regenerated fluids to sorbent-B 1005, sorbent-C 1009, and collector

[0191] 1013, respectively. Each chamber is isolated and separated by the walls 1003, 1007, and 1011 and regenerated fluids from the previous chamber enters the next chamber through valves

[0192] 1004, 1008, and 1012, respectively.

[0193] Figure 11 is another embodiment of this invention employing multiple cascaded sorbent units that are cascaded together to form multiple stages. We will call each cascaded sorbent unit in this multi-stage system a cascaded sorbent module. In this example, we have a

[0194] 3-stage 2-cascaded sorbent system design, where we have three 2-cascaded sorbent modules cascaded together to form three stages. The three 2-cascaded sorbent modules are 1100, 1110, and 1120. In the 2-cascaded sorbent module 1100, there are the two cascaded sorbents 1101 and 1103 and collector 1105. The regenerated fluid 1102 produced from sorbent 1101 during its regeneration is transferred and contacted to the subsequent sorbent 1103. After sorbent

[0195] 1103 captures the target species from the regenerated fluid 1102, it subsequently regenerates to produce a regenerated fluid 1104 that transfers and contacts collector 1105. Similarly, the

[0196] 2-cascaded sorbent module 1110 has two cascaded sorbents 1111 and 1113 that each produce regenerated fluids 1112 and 1114, respectively. Regenerated fluid 1112 from sorbent 1111 contacts sorbent 1113 that subsequently produces regenerated fluid 1114 that contacts collector 1115. The third 2-cascaded sorbent module 1120 has two cascaded sorbents 1121 and 1123 that each produce regenerated fluids 1122 and 1124, respectively. Regenerated fluid

[0197] 1122 from sorbent 1121 contacts sorbent 1123 that subsequently produces regenerated fluid

[0198] 1124 that contacts collector 1125. The advantage of the multi-stage embodiment of cascaded sorbent modules is each stage of the cascaded sorbent modules can operate at different ranges of temperature. For example, the first module can have capture and regeneration operational temperatures that are higher than a second module. By operating each stage of the modules at different temperatures, we can utilize heat transfer to recycle the heat from the higher operating temperature module down to the lower operating temperature module. For example, in this embodiment, module 1100 operates at higher capture and regeneration temperatures than module 1110; and module 1110 operates at higher capture and regeneration temperatures than module 1120. Therefore, we can transfer excess heat from the sorbents inside modules 1100,

[0199] 1110, and 1120 through heat transfer paths 1140 and 1150. The heat transfer implementation can include but is not limited to pipes that carry heating / coolant fluid (liquid or gas), heat pipes, and / or thermal conductors that carry heat from one sorbent to another sorbent. The heat transfer for the first sorbents 1101, 1111, and 1121 in modules 1100, 1110, and 1120 is through 1140. The heat transfer among the second sorbents 1103, 1113, and 1123 in modules

[0200] 1100, 1110, and 1120 is through 1150. Both pathways can flow in either direction, depending on which module is operating at higher temperature relative to the other. The heat carried through 1140 from sorbent 1101 down to sorbent 1121 is then taken to a thermal element

[0201] 1131 that can include but is not limited to a heat exchanger, pre-heater, heat transfer pipe, pipe carrying a heating / coolant fluid, and / or thermal conductor that transfers heat to the second sorbents 1123, 1113, and 1103 through heat transfer pathway 1150. Similarly, the heat at the end of the pathway 1150 cycles back to heat transfer pathway 1140 through a thermal element 1130 that can include, but is not limited to a heat exchanger, pre-heater, heat transfer pipe, pipe carrying a heating / coolant fluid, and / or thermal conductor. Similarly, we can transfer heat along the second set of sorbents through 1160 and recycle back to the set of collectors through 1170. Heat is cycled back through thermal elements 1133 and 1132, which may include but aren’t limited to heat exchangers, pre-heaters, heat transfer pipes, pipes carrying heating / coolant fluid, and / or thermal conductors.

[0202] To further explain the operation of multi-stage cascaded sorbent systems, we take an example of a 2-stage 2-cascaded sorbent system as shown in Figure 12A and Figure 12B.

[0203] We have two 2-cascaded sorbent module 1200 and 1210, where 1200 operates at 25°C capture and 40°C regeneration temperatures and 1210 operates at higher 40°C capture and

[0204] 60°C regeneration temperatures. In this example, we use the same sorbents, sorbent-A and sorbent-B for both modules, but they do not necessarily have to be the same. The embodiment of the invention is to ensure the sorbents inside the same module are cascaded such that the two design features are met: transfer ratio from first sorbent to second sorbent is non-zero and target species concentration in regenerated fluid produced from second sorbent is greater than in a regenerated fluid produced from first sorbent at same regeneration temperatures. For multi-stage systems, the embodiment of the invention is to have each module operate at different ranges of temperatures than another to allow for heat transfer and recycling.

[0205] Similar to Figure 7 for a single stage 2-cascaded sorbent system, we label the transfer characteristics of the sorbents with input and output threshold pressures that are taken from the sorption isotherm curves for each sorbent at each temperature. In the first cycle shown in

[0206] Figure 12 A, first sorbents 1211 and 1201 in both modules are in their regeneration phase.

[0207] We illustrate this by crossing out the input threshold pressure because this is applicable to the capture phase. First sorbents 1211 and 1201 in Figure 12A are at regeneration temperatures and producing the regenerated fluid in 1212 and 1202, respectively. Sorbent-A 1201 is regenerating at 40°C. Therefore, the 25°C threshold pressure is crossed out because sorbent¬

[0208] A is not at 25°C but at 40°C during its regenerating phase. This is after their capture phase where we let input fluid through valves 1220. After input fluid is contacted to first sorbents 1201 and 1211 through valves 1220, the valves 1220 are closed and first sorbents 1201 and

[0209] 1211 are then regenerated. This is the phase that is illustrated in Figure 12A. The first sorbents 1201 and 1211 are producing regenerated fluid that then transfer and contact the second sorbents 1203 and 1213, which are both at their capture temperatures. The second sorbents 1213 and 1203 have their output threshold pressures crossed out because those are not applicable for the capture phase. The excess heat during regeneration of first sorbent 1211 is transferred to first sorbent 1201 that is operating at a lower regeneration temperature. The heat from first sorbent 1201 can then be optionally transferred over to the second sorbent

[0210] 1203. Since the second sorbent 1203 is contacting the regenerated fluid from first sorbent

[0211] 1201, it starts to heat up and increase in temperature. This excess heat produced in second sorbent 1203 is transferred to second sorbent 1213 that is operating at a higher capture temperature than second sorbent 1203. Note that the thermal contacts for the sorbents 1211,

[0212] 1201, 1203, and 1213 are A11 / A12, A21 / A22, B22 / B21, and B12 / Bll, respectively. Without wishing to be bound by specific implementation of the embodiment, these can include but are not limited to pipes carrying heating / coolant fluid, heat transfer pipes, and / or thermal conductors. The heat transfer from one sorbent to another can be the same or different as the way to heat up the sorbents to different temperatures. There can be additional electrical heaters or other heating elements in addition to the heat transfer and recycling elements. In other words, there can be an electrical heater or other heating element connected to first sorbent 1201 other than the element that carries excess heat from first sorbent 1211 to first sorbent 1201. This may happen when the excess heat recycled from first sorbent 1211 is insufficient to heat up first sorbent 1201 to its desired operating temperature so that we would need additional heating elements to provide additional heat to first sorbent 1201.

[0213] Figure 12B illustrates the next cycle where the second sorbents 1203 and 1213 switch over to regeneration after capturing the target species from the regenerated fluid produced from the first sorbents in the previous cycle in Figure 12A. In Figure 12B, the second sorbents 1203 and 1213 are at their regeneration temperatures; therefore, the input threshold pressures at their capture temperatures are crossed out (25°C for second sorbent 1203 and

[0214] 40°C for second sorbent 1213). In the previous cycle illustrated in Figure 12A, first sorbents

[0215] 1211 and 1201 were regenerating at 60°C and 40°C, respectively. After releasing as much of the target species captured on the first sorbents, we now switch to capture phase in Figure

[0216] 12B. In this cycle, valves 1220 are opened to let input fluid contact first sorbents 1211 and

[0217] 1201 to capture more target species from this input fluid. The target species captured on second sorbents 1203 and 1213 are now released into regenerated fluids that are then transferred and contacted to the collectors 1205 and 1215. Since second sorbent 1213 is operating at a higher regeneration temperature of 60°C than second sorbent 1203 at 40°C, the excess heat from second sorbent 1213 can be transferred and recycled to second sorbent

[0218] 1203. Note that since second sorbent 1203 is releasing the target species, it will lose heat.

[0219] This heat is collected and transferred over to collector 1205. Collector 1205 will condense the regenerated fluid from second sorbent 1203. Since this regenerated fluid is at a higher temperature than the collector 1205, it will increase the temperature of collector 1205. This excess heat gained can be transferred and recycled to collector 1215 that is operating at a higher temperature.

[0220] This embodiment of the invention of employing multi-stage cascaded modules aims to design each module such that they operate at different ranges of temperatures such that heat and / or pressure energy can be transferred and recycled from one cascaded module to another since one module will operate at higher temperature or pressures than another module.

[0221] The capability to operate at different ranges of operating temperatures to enable energy recycling is accomplished with multi-stages of cascaded modules, instead of multi- stages of single sorbent modules. For example, if we remove the second sorbents 1213 and

[0222] 1203 from Figure 12A and only have a single sorbent type, Sorbent-A, in modules 1200 and

[0223] 1210, then when we transfer the excess heat energy from sorbent 1211 to sorbent 1201 because 1211 operates at regeneration temperature 60°C while 1201 operates at regeneration temperature 40°C, the regenerated fluid output of 1201, at lower regeneration temperatures, can only have maximum 1.4 kPa, which is insufficient to condense water at the condenser

[0224] 1205 running at 25 °C operating temperature. There is no useable condensed liquid output from sorbent 1201 even if we can operate it at recycled energy from sorbent 1211. However, with this invention, the 2-cascaded sorbent module 1200 can still operate below 40°C for both sorbents 1201 and 1203 and still produce useable condensed liquid at collector 1205.

[0225] Therefore, heat energy that is recycled from the 2-cascaded sorbent module 1210 can be used to operate the module 1200. The invention employs cascaded sorbents within each module so that it can operate at lower regeneration temperatures to produce high enough target species concentration after the last sorbent. The lower operating temperature for one cascaded sorbent module can be run from recycled energy from another higher-operating-temperature module. An embodiment of this invention is to enable cascaded modules to operate at lower operating temperatures and yet still produce a high enough target species concentration in the regenerated fluid produced from the last sorbent.

[0226] Figure 13 outlines the general operational steps for n-stage cascaded sorbent system.

[0227] We will refer to each cascaded sorbent system as a module. There are “n” cascaded sorbent modules. In each of the cascaded sorbent module, there is at least a first and second sorbent and possibly more sorbents cascaded after that, where the first sorbent first captures the target species from an input fluid and then releases the target species to produce a regenerated fluid that is then contacted to the second sorbent that captures the target species from the regenerated fluid produced from the first sorbent. The second sorbent then releases the target species to produce a regenerated fluid that is then contacted to a possible third sorbent that captures the target species from the regenerated fluid of the second sorbent. This continues on until the last sorbent that produces a regenerated fluid that is contacted to a collector that can either pressurize, condense, concentrate, or further capture the target species to a final sorbent storage material. The first set of sorbents will refer to the first sorbents in all “n” cascaded sorbent modules. The second set of sorbents will refer to the second sorbents in all “n” cascaded sorbent modules. The set of collectors will refer to the collectors in all “n” cascaded sorbent modules. The first operational step 1310 is contacting the input fluid containing the target species to the first set of sorbents in all modules. Since they are the first sorbents, their capture temperatures are ideally the same because their process fluid are the same input fluid.

[0228] The second operational step 1320 is to regenerate the first set of sorbents at their respective regeneration temperatures while at the same time excess heat is transferred from a first sorbent in one module to another first sorbent in another module, which can then be transferred to another first sorbent in yet another module, assuming there are more than two modules. This can happen because in the n-stage design, the first sorbents in each module operate at different regeneration temperatures. The first sorbent operating at a higher regeneration temperature can transfer its excess heat to another first sorbent in another module that operates at a lower regeneration temperature. The third operational step 1330 is contacting the regenerated fluids from the first set of sorbents to the second sorbents in their respective modules. Since the regenerated fluids from the first set of sorbents will be at higher regeneration temperature than the capture temperatures of the second set of sorbents, the second set of sorbents will increase in temperature. This heat energy can be recycled and transferred among the second set of sorbents. The excess heat gained from one of the second sorbents can be transferred to another second sorbent in another module. Similar to the first sorbents, the second sorbents in each module operate at different capture and regeneration temperatures such that excess heat energy from one of the second sorbents can be transferred to another second sorbent in another module. The next operational step 1340 is to regenerate the second set of sorbents at their respective regeneration temperatures and since the regeneration temperatures of each of the second set of sorbents are different, excess energy, including in the form of heat, can be transferred from one second sorbent to another second sorbent. Operational step 1350 is a repetition of steps 1330 and 1340, except the regenerated fluid is contacted to the subsequent cascaded sorbent, such as third sorbent and then fourth sorbent, and so on. Operational step 1360 is at the last stage of the sorbent in the cascade when we contact the regenerated fluid from the last sorbents in all modules to collectors in their respective modules. Since regenerated fluids from the last set of sorbents will be at higher temperature than the operating temperature of the collectors, the collectors will gain some heat energy. This heat energy can be recycled and transferred among the collectors.

[0229] Another embodiment of this invention is to leverage the ability to tune the operating temperature range of the sorbent system (by selecting sorbents) to operate at temperatures that are readily available from natural energy sources and / or waste energy (from other systems) and yet still achieve a desired target species concentration in a regenerated fluid.

[0230] Figure 14 is an example embodiment of a 2-cascaded sorbent system where the operating temperature range is from capture temperature TC to regeneration temperature TR. This system is designed to operate from natural or waste energy sources that provide a low temperature TC and a high temperature TR; therefore, operating the sorbents and collectors will have to be at those naturally or freely available temperatures. The first sorbent 1401, second sorbent 1402, and collector 1403 are set to temperature TC or TR through A1 / A2,

[0231] B1 / B2, and C1 / C2 elements, respectively. Similar to prior examples, the A1 / A2, B1 / B2, and

[0232] C1 / C2 elements are responsible for setting the temperatures of the sorbents and collector and can include but are not limited to pipes carrying heating / coolant fluid, heat transfer pipes, and / or thermal conductors. They will transfer the heat energy from the natural or waste energy sources to the individual sorbents and collector elements to set the temperatures of said elements. The first sorbent 1401 and second sorbent 1402 are chosen with sorption isotherms such that for given temperature and target species concentration in the input fluid and temperatures TC and TR, the system can still produce a regenerated fluid contacting collector 1403 at the desired target species concentration. Using the example of a water harvester where ambient air is the input fluid, we want the vapor pressure of the regenerated fluid contacting condenser 1403 to be large enough such that the dew point is below temperature TC. From the prior discussions, the vapor pressure can be increased by cascading sorbents. If the ambient air has low relative humidity such that the water vapor pressure is in the depletion region of second sorbent 1402 (i.e., minimal uptake of water by sorbent 1402 when ambient air is contacted to it), then the ambient air first passes to first sorbent 1401 through valve 1420. If after regeneration at TR, the first sorbent 1401 cannot produce a regenerated fluid with water vapor pressure that can readily condense liquid water at the condenser 1403 at temperature TC, then the regenerated fluid is passed to second sorbent

[0233] 1402 through valve 1422. The second sorbent 1402 is kept at capture temperature TC while exposed to regenerated fluid from first sorbent 1401. After target species is captured from the regenerated fluid to second sorbent 1402, the second sorbent 1402 is regenerated at temperature TR to produce a regenerated fluid that is passed through valve 1424 to contact the condenser 1403 to condense liquid water. However, if after regeneration at temperature

[0234] TR of the first sorbent 1401, the first sorbent produces a regenerated fluid with high enough water vapor pressure to condense liquid water when contacted to condenser 1403 at temperature TC, then the regenerated fluid produced from first sorbent 1401 can be passed directly to the collector by opening valves 1421 and 1426 such that the fluid pathway bypasses the second sorbent 1402 (valve 1422 is kept closed). In another situation, if the ambient air happens to have high relative humidity such that the second sorbent 1402 can readily capture target species from the ambient air in its saturation region, then the input ambient air can be contacted to second sorbent 1402 through valve 1423 where second sorbent 1402 is maintained at temperature TC through B1 / B2. After the second sorbent 1402 captures the target species from the ambient air input, then valve 1423 is closed and second sorbent 1402 is regenerated at temperature TR through B1 / B2. A regenerated fluid is produced and then transferred through valve 1424 to contact the condenser 1403 at temperature TC to condense liquid water. Therefore, for high relative humidity ambient air, the first sorbent is not used at all. In the extreme situation for very high relative humidity where water can easily condense at temperature TC, the ambient air can be transferred through valve 1425 to contact the condenser 1403 at temperature TC through C1 / C2. In this very high relative humidity ambient air condition, both first sorbent and second sorbent are bypassed and not used since the ambient air can readily condense liquid water at temperature

[0235] TC. The example system in Figure 14 illustrates the option to bypass sorbents depending on the input fluid conditions. It also illustrates that there are only two operating temperature set points for the system, where the temperature of the active elements, such as the sorbents and collectors, can be set from natural and waste thermal energy sources, which can include but are not limited to, ambient air, solar irradiation heat, underground temperature, waste water temperature, waste heat from industrial operations, sea water or other bodies of water. One can use the ambient air heat and the underground temperature to cycle the capture and regeneration phases of the sorbents. The system can have sensors to measure the temperature of the natural or waste energy source and the temperature and concentration of the input fluid source and determine the process fluid pathway, such as which sorbents to contact and how many sorbents to cascade. The system illustrated in Figure 14 can have a fluid pathway that starts from ambient air that contacts first sorbent, second sorbent, and collector sequentially, or contacts first sorbent then collector, or contacts second sorbent then collector, or contacts collector directly bypassing first and second sorbents. The process fluid pathway can be any of these depending on the temperatures of the natural and waste energy sources and the temperature and target species concentration in the input fluid. Similar to other embodiments, since the regenerated fluid is at a higher temperature than the capture temperature of the sorbent the regenerated fluid is contacting, the extra thermal energy due to this temperature difference can be transferred or recycled back into the system or stored in a thermal storage.

[0236] For example, a heat exchanger can collect or recycle the regenerated fluid temperature before the regenerated fluid contacts another sorbent.

[0237] Figure 15 is a block diagram of an embodiment of this invention implementing a 2- cascaded sorbent system that illustrates the process fluid pathway, denoted with solid lines, and the temperature-control pathway marked with dashed lines. This can be easily expanded to more than 2 sorbents and similarly add multiple stages with separate cascaded modules as explained in Figures 11, 12, and 13. The elements 1510, 1511, 1512, 1513, and 1514 drawn with solid lines are pathways for the process fluid containing the target species and can include but are not limited to pipes, tubing, and / or connections to carry and transport the process fluid (liquid or gas) to contact the sorbents 1501 and 1502 and collector 1503 elements. The elements drawn like 1540 can include but are not limited to flow valve, slide valve, gate valve, or any type of valve or element that can control the time and / or flow of the process fluid or heating / coolant fluid. The input fluid, which can be ambient air with target species as water or carbon dioxide or a flue gas with target species carbon dioxide, goes through pathway 1510, where there are valves that can control if the input fluid contacts

[0238] 1501, 1502, or 1503. First sorbent is 1501, second sorbent is 1502, and the collector is 1503.

[0239] Input fluid can first contact first sorbent 1501 and then the regenerated fluid produced from

[0240] 1501 can either be transferred to 1502 through pathway 1512 or bypass second sorbent 1502 and contact collector 1503 through pathway 1511. Input fluid can contact first sorbent 1501 through pathway 1510, where first sorbent 1501 is held at some capture temperature through thermal conducting elements 1524 and 1525. After some of the target species is captured onto first sorbent 1501 from the input fluid, first sorbent 1501 can be subsequently regenerated at a regeneration temperature set by 1524 and 1525. The regenerated fluid produced from first sorbent 1501 can then be transferred and contacted to second sorbent 1502 through 1512, while second sorbent 1502 is set at a capture temperature set by thermal conducting elements

[0241] 1522 and 1523. The dashed lines 1520, 1521, 1522, 1523, 1524, and 1525 represent thermal conducting elements that will transfer heat energy between 1504 or 1505 and the individual sorbents 1501 and 1502 and collector 1503 elements to set the temperatures of said sorbents and collector. The thermal conducting elements can include but are not limited to pipes that cany heating / coolant fluid (liquid or gas), heat pipes, and / or other thermal conductors that cany heat from one element to another. The temperature reservoir elements 1504 and 1505 set the temperatures of the sorbent and collector elements. First sorbent 1501 can be thermally connected to 1504 or 1505 through thermal conduction pathways 1524 and 1525.

[0242] We can implement this as a heating / coolant fluid that contacts first sorbent 1501 from 1525 to transfer heat between first sorbent 1501 and the heating / coolant fluid and then the heating / coolant fluid exits through 1524 and goes to 1504 or 1505. The heating / coolant fluid can exchange heat at 1504 or 1505 and then circulate back to first sorbent 1501. This heating / coolant fluid thermally connects first sorbent 1501 with temperature reservoir elements 1504 or 1505 to help set the temperature of first sorbent 1501 to the reservoir temperature of 1504 or 1505. The temperature reservoir 1504 and 1505 have to have a heat capacity that is large enough such that the reservoir temperature does not change a lot when a given amount of heat is added or reduced after heat exchange with the heating / coolant fluid that is circulating within the system. In other words, the amount of heat exchanged from the sorbent and collector elements should ideally not change the temperature of the reservoirs significantly. The temperature reservoir elements 1504 and 1505 can be composed of heat exchangers that exchange heat from the heating / coolant fluids (liquid or gas) to set the temperatures of the heating / coolant fluids that later contact the sorbent 1501 and 1502 and collector 1503 elements. The elements 1504 and 1505 can be additionally composed of one or more thermal storage elements that collect and store heat energy from the sorbents or collectors or from external heat sources, including but not limited to natural and / or waste thermal energy sources, such as ambient air heat energy, solar irradiation heat energy, or heat energy from a waste stream from industrial operations. The temperature of the temperature reservoir can have another heat exchanger that sets its temperature to ambient temperature of ambient air, underground earth temperature, solar irradiation temperature, waste water temperature, sea water or other bodies of water temperature. Note that there can be more than 2 temperature reservoirs in addition to 1504 and 1505, but the minimum is two since the individual sorbents operate at a capture temperature and a higher regeneration temperature.

[0243] The operating temperature of the collector 1503 is chosen to be at the capture temperature to limit the number of temperature reservoir elements to two, but this invention is not limited to the number of temperature reservoir elements. The various valves, such as 15400, connected in series to the thermal conduction pathways (dashed lines) control the flow of the thermal energy to operate the sorbents 1501 and 1502 and collector 1503 at the temperatures of the temperature reservoir elements 1504 and 1505. Therefore, at any given time, sorbents 1501 and 1502 and collector 1503 can either be in thermal contact with 1504 or 1505 to set the temperature of the sorbents and collector at either reservoir temperature of 1504 or 1505. An additional feature of this system is the output fluid pathway of 1503 where the output fluid of

[0244] 1503 after the process fluid contacts 1503 can be recycled back to first sorbent 1501 and / or second sorbent 1502 through fluid pathway 15150. This is provided such that some of the target species remaining in the fluid that hasn’t condensed as a product in 15300 can be optionally recycled back and re-captured by first sorbent 1501 and / or second sorbent 1502.

[0245] Figure 16 a block diagram that illustrates the temperature control management system that sets the temperatures of the sorbents and collectors by coupling to natural or passive heat energy sources and heat sinks. Natural or passive heat energy sources refer to exogenously generated heat sources, such as solar irradiation, hot ambient air, and / or waste streams ftom industrial processes. Natural or passive heat sinks refer, e.g., to ambient air convection, underground earth conduction, exogenous body of water or water stream. In

[0246] Figure 16, the module 1600 is the block that comprises one or more sorbent and collector.

[0247] Referring to the Figure 15 system, the 1600 module would comprise the elements 1501,

[0248] 1502, and 1503, as well as the process fluid connections 1511, 1512, 1513, and 1514. The input fluid is 1630 that enters the module and contacts the sorbents whenever they need to capture additional target species from the input fluid. There is a plurality of sensors 1660,

[0249] 1661, 1662, and 1663 that can measure target species concentration and temperature. The dashed lines 1640, 1641, 1642, and 1643 represent thermal conduction pathways between sorbent module 1600 and the temperature control elements 1610 and 1611 and can be pipes or tubing recirculating a heating / coolant (or heat exchange) fluid. The elements 1620, 1621, and 1622 represent heat exchange or collector elements that either exchange heat with or collect heat ftom the external natural or passive heat energy sources and / or heat sinks. The temperature control elements 1610 and 1611 can be composed of one or more heat exchangers, temperature reservoirs, and / or valves that manage the temperature of the heat exchange fluid exiting through 1641 and 1643 such that the correct temperature is set for the sorbents and collectors inside 1600 that contact the heat exchange fluid coming ftom 1641 and 1643. To better illustrate the operation of this system, we can use a specific embodiment where the input fluid is ambient air containing target species that is water. The sensor 1660 measures the temperature and humidity of the ambient air to determine how to route the process fluid within the sorbent module 1600. The temperature control element 1611 is at a low temperature that sets the capture temperature of the sorbents in module 1600. The temperature control element 1610 provides a higher temperature that sets the regeneration temperature of the sorbents in module 1600. The elements 1640 and 1641 can form the recirculating pathway carrying a heat exchange fluid that exchanges heat between the sorbents and the temperature control element 1610. Similarly, the elements 1642 and 1643 can form the recirculating pathway carrying a heat exchange fluid that exchanges heat between the sorbents and collector and the temperature control element 1611. Since 1610 sets the higher regeneration temperature, it uses heat harvesting elements 1620 and 1621. The heat harvester element 1620 can be a solar collector or concentrator that collects heat from solar irradiation. The heat harvester element 1621 can be a heat exchanger that collects heat from the hot ambient air. Using sensors 1661 and 1662, the system can determine if there is sufficient heat collected or exchanged from 1620 or 1621 to transfer to the temperature control element 1610. For example, if the temperature of the heat exchange fluid in 1652 detected by sensor 1662 is not high enough, then the heat exchange pathway 1652 and 1653 can be disconnected from the temperature control element 1610. The method to disconnect can be done with a valve that closes and / or a pump that stops the flow of the heat exchange fluid in 1652 and 1653 from circulating between 1621 and 1610. Note that the heat exchange fluid leaving 1621 in 1652 is heated by ambient air contacting 1621, so there can be times when the temperature of the ambient air is determined to not be hot enough. Alternatively, the temperature control element 1610 can take the heat exchange fluid coming from 1652 and heat it up further with the heat exchange fluid circulating through 1650 and 1651. Heat exchange fluid in 1650 and 1651 can be significantly hotter because it is heated by a solar concentrator. This hotter heat exchange fluid is then used to heat up a temperature reservoir in 1610 that will be used to set the regeneration temperature of the sorbents inside 1600 by heating the heat exchange fluid coming from 1640. Since the temperature control element

[0250] 1611 is in charge of setting the lower capture temperature, it will be connected to a heat exchange element 1622 that is in contact with something at lower temperature. The temperature control element 1611 can pass the heat exchange fluid in 1642 directly to 1655 and then exchange heat in 1622 with a heat sink, such as underground earth or natural body of water. Note that the temperature control elements 1610 and 1611 set the temperatures of the heat exchange fluids exiting through 1641 and 1643 by coupling to various heat harvester or heat exchanging elements 1620, 1621, and 1622, which are coupled to natural or passive heat energy sources or heat sinks, which can include ambient air, solar irradiation, underground earth, natural bodies of water, waste streams from industrial processes such as flue gas or waste water. These temperature control elements can be complex with one or more temperature reservoirs to store energy for long term use, or they can only be composed of valves and / or pumps that either start or stop the flow of the heat exchange fluid in 1640,

[0251] 1641, 1642, and 1643 with the heat exchange or collector elements 1620, 1621, and 1622. For example, if 1622 is a heat exchange element coupled to an underground earth heat sink, the temperature control element 1611 can simply be a valve and / or pump that when turned on or off will start or stop the flow of heat exchange fluid coming from 1642 going to 1655 and contacting element 1622 and circulating back through 1643.

[0252] The invention illustrated in Figure 16 aims to power the sorbent system passively using exogeneous sources of heat energy and heat sinks, where the heat energy source is used to heat up the sorbent to the regeneration temperature and the heat sink is used to lower the sorbent temperature to the capture temperature. The sorbents in the system need two operating temperatures, capture and regeneration temperatures; therefore, it is insufficient to only provide a heat energy source, but the system also needs to actively set a lower capture temperature by coupling the sorbent to a heat sink at lower temperature. The temperature control elements manage the operating temperatures of the sorbents in the module to toggle between capture and regeneration temperatures through coupling with the exogenous heat energy sources and heat sinks. In the previous example, temperature control element 1611 sets the capture temperature by coupling to an underground earth heat sink using 1622 and the other temperature control element 1610 sets the higher regeneration temperature by coupling to a heat collector 1620 to harvest solar irradiation and a heat exchanger 1621 to harvest hot ambient air heat. This can work during the summer time, but during the winter time, the system can reverse the roles of the temperature control elements such that the temperature control element 1611 coupled to the underground earth through 1622 provides the higher regeneration temperature and the temperature control element 1610 coupled to ambient air through 1621 provides the colder capture temperature. This can be done if ambient air during winter is colder than underground earth temperature. Another embodiment of this passive system is to include thermal storage elements to act as temperature reservoirs, where the temperature of the reservoirs can be used at a later time to set the capture and regeneration temperatures of the sorbents. The temperature control element 1610 can contain a thermal storage element such that in the summer during the day, the thermal storage element heats up to a high temperature. Then during the night when not much heat energy can be collected from solar irradiation from 1620 or ambient air heat from 1621, the temperature control element 1610 can set the sorbent in module 1600 to the regeneration temperature by using the thermal storage element (temperature reservoir) that was heated earlier during the day. During the night time, the sorbent in 1600 can be set to the lower capture temperature by coupling to cold ambient air heat sink and / or underground earth heat sink by using temperature control elements 1610 with 1621 and / or 1611 with 1622. Note that for illustration purposes, the temperature control management was divided into two separate temperature control elements 1610 and 1611 to manage the two different temperature settings separately, one for capture temperature and the other for regeneration temperature. However, the system can be made more robust where there is a single temperature control element that is coupled to both sets of heat exchange fluid circulation pathways 1640 / 1641 and 1642 / 1643 as well as all the heat exchange and heat collector elements 1620, 1621, and 1622. This single temperature control element that merges 1610 and 1611 can be composed of valves, pumps, and / or temperature reservoirs to manage heat transfer and heat exchange between the exogenous heat energy sources and heat sinks from 1620, 1621, and 1622 and the temperature reservoirs and / or module 1600.

Claims

Claims:

1. A system configured to capture a target chemical species from a fluid comprising the target chemical species, comprising: at least one first sorbent that can be set to a first capture temperature and configured to receive an input fluid comprising the target chemical species; the at least one first sorbent configured to be subsequently heated to a first regeneration temperature to generate a first regenerated fluid comprising a higher target chemical species concentration or partial pressure than in the input fluid; at least one second sorbent that can be set to a second capture temperature, which may be the same or different from the first capture temperature, and configured to receive the first regenerated fluid from the at least one first sorbent to capture target chemical species from the first regenerated fluid; the at least one second sorbent is configured such that there is a nonzero mass of target chemical species transferred from the first regenerated fluid to the at least one second sorbent at the second capture temperature; and the at least one second sorbent configured to be subsequently heated to a second regeneration temperature to generate a second regenerated fluid comprising a higher target chemical species concentration or a partial pressure than the first regenerated fluid if the first regeneration temperature is equal to the second regeneration temperature.

2. The system of claim 1, wherein the at least one second sorbent is configured such that a mass of target chemical species transferred from the first regenerated fluid produced from the at least one first sorbent at the first regeneration temperature to the at least one second sorbent at the second capture temperature divided by a sum of a mass of targetchemical species in the at least one second sorbent and a mass of target chemical species in the at least one first sorbent is greater than 0.05.

3. The system of claim 1, wherein at least one collector element is configured to receive the second regenerated fluid from the at least one second sorbent to concentrate, compress, condense, and / or capture the target species, or if the at least one collector element is the same as the at least one second sorbent, the at least one collector element is configured to receive the first regenerated fluid to concentrate, compress, condense, or capture the target species.

4. The system of claim 1, wherein one or more sorbents are connected in series after the at least one second sorbent and before at least one collector element, wherein at least one third sorbent at a third capture temperature is configured to receive the second regenerated fluid from the at least one second sorbent, and the at least one third sorbent is configured to subsequently heat at a third regeneration temperature to generate a third regenerated fluid.

5. The system of claim 1 , configured such that when a regenerated fluid produced from one sorbent at a regeneration temperature comes into contact with the next sorbent at a capture temperature, absorbed heat energy gained by the next sorbent is transferred or recycled back to a different sorbent or transferred to a thermal storage unit.

6. The system of claim 1, configured such that before a regenerated fluid produced from one sorbent at a regeneration temperature come into contact to the next sorbent at a capture temperature, thermal energy of the regenerated fluid is transferred or recycled backinto the system or thermal storage such that a temperature of the regenerated fluid lowers towards the capture temperature of the contacted sorbent.

7. The system of claim 1, configured such that if the input fluid is at a higher temperature than a capture temperature of a contacted sorbent, thermal energy from a difference in an input fluid temperature and a sorbent capture temperature is transferred or recycled back to a different sorbent or transferred to a thermal storage unit.

8. The system of claim 1 , configured such that before a regenerated fluid produced from one sorbent at a regeneration temperature comes into contact to the next sorbent at a capture temperature, the regenerated fluid contacts a heat exchanger element to lower the temperature of the regenerated fluid closer to the next sorbent capture temperature and energy transferred to the element is transferred or recycled back to another sorbent in the system or transferred to a thermal storage unit.

9. The system of claim 1, configured to set a temperature of one or more sorbents by flowing a heat exchange fluid comprising air or liquid that contacts passive or natural heat energy sources or heat sinks comprising ambient air, air at high elevation, underground earth, solar irradiation, waste stream byproduct from industrial processes, natural bodies of water or reservoirs.

10. The system of claim 1, wherein the target species is water, carbon dioxide, hydrogen, nitrogen, oxygen, ammonia, methane, ethane, carbon monoxide, alcohol, sulfur dioxide, hydrogen sulfide, nitrogen oxide, or sulfur oxide.

11. The system of claim 1, where the input fluid is ambient air containing water and / or carbon dioxide, flue gas containing water and / or carbon dioxide, compressed air, gas containing the target species, or liquid containing the target species.

12. The system of claim 1 , wherein a process fluid pathway can be changed based on a temperature of and a target species concentration in a process fluid such that the process fluid bypasses one or more sorbents and omits a sequential order of the one or more sorbents.

13. The system of claim 1, where, after the first regenerated fluid produced from the at least one first sorbent at the first regeneration temperature comes into contact with the at least one second sorbent at the second capture temperature or a collector element, the second processed fluid is redirected back to contact the at least one first sorbent.

14. The system of claim 13, wherein a heat exchange element transfers heat between the regenerated fluid from the at least one first sorbent at the first regeneration temperature and the processed fluid from the at least one second sorbent at the second capture temperature or a collector element at a second capture temperature, and wherein the regenerated fluid contacts the heat exchange element before contacting the second sorbent or a collector element.

15. A system configured to capture a target chemical species from a fluid containing said target chemical species, comprising:at least one module comprising the system of claim 1 connected to another module comprising the system of claim 1 , wherein heat or pressure energy is transferred or recycled from sorbents from one module to another module; wherein a maximum operating temperature of the at least one module is lower than a minimum operating temperature the another module.

16. The system of claim 15, wherein collector elements in each module are connected to transfer and recycle heat or pressure energy from a collector from the at least one module to the another module.

17. The system of claim 15, wherein thermal energy is recycled or transferred from one sorbent to another sorbent by heat exchange through a fluid, wherein the fluid is air and liquid.

18. A system configured to capture target species from a fluid containing the target chemical species, comprising: at least one sorbent that can be set to a capture temperature and configured to receive an input or process fluid comprising target chemical species; the at least one sorbent configured to be subsequently heated to a regeneration temperature to generate a regenerated fluid; the at least one sorbent is set to a capture temperature by exchanging heat with one or more temperature reservoirs and / or one or more temperature control elements coupled to one or more heat exchange elements that are coupled to one or more passive or natural heat sinks; wherein the at least one sorbent is set to a higher regeneration temperature by exchanging heat with the one or more temperature reservoirs and / or the one or moretemperature control elements coupled to the one or more heat exchange and / or heat collector elements that are coupled to one or more passive or natural heat energy sources; the one or more temperature control elements that manage the heat exchange or heat transfer between an exogenous heat source or heat sink and the at least one sorbent.

19. The system of claim 18, wherein the passive or natural heat energy sources comprises ambient air heat, solar irradiation, waste heat from industrial processes, underground earth heat, or a combination thereof.

20. The system of claim 18, wherein the passive or natural heat sinks comprises natural bodies of water, underground earth, ambient air at low or high elevation, or a combination thereof.

21. The system of claim 18, further comprising a plurality of sensors to monitor an input fluid temperature and a target species concentration and adjust a process fluid path of the input fluid and regenerated fluids to contact the at least one sorbent or bypass and contact the collector element directly.

22. The system of claim 18, further comprising a plurality of sensors to monitor a temperature of the natural or passive heat energy sources and / or heat sinks and adjust the heat exchanged between the sorbent and the natural or passive heat energy sources and / or heat sinks.

23. The system of claim 18, further comprising one or more thermal storage elements that act as a temperature reservoir, set to a cold or hot temperature from exogeneous heatsources or heat sinks, which can be used to set the capture or regeneration temperature of the at least one sorbent24. A method of capturing a target chemical species from a fluid containing the target chemical species, the method comprising receiving an input fluid comprising target chemical species with at least one first sorbent that can be set to a first capture temperature; heating the at least one first sorbent to a first regeneration temperature to generate a first regenerated fluid comprising a higher target chemical species concentration or partial pressure than present in the input fluid; receiving the first regenerated fluid from the at least one first sorbent to capture target chemical species from the first regenerated fluid with at least a second sorbent that can be set to a second capture temperature, which may be the same or different from the first capture temperature; wherein the at least one second sorbent is configured such that there is a nonzero mass of target chemical species transferred from the first regenerated fluid to the at least one second sorbent at the second capture temperature; and wherein the at least one second sorbent configured to subsequently heat to a second regeneration temperature to generate a second regenerated fluid comprising a higher target chemical species concentration or a partial pressure than in the at least one first regenerated fluid if the first regeneration temperature were equal to the second regeneration temperature.

25. The method of claim 24, wherein the at least one second sorbent is configured such that a mass of target chemical species transferred from the first regenerated fluid produced from the at least one first sorbent at the first regeneration temperature to the at leastone second sorbent at the second capture temperature divided by a sum of a mass of target chemical species in the at least one second sorbent and a mass of target chemical species in the at least one first sorbent is greater than 0.05.

26. The method of claim 24, wherein at least one collector element receives the first regenerated fluid from the at least one second sorbent to concentrate, compress, condense, and / or capture the target species or if the at least one collector element is the same as the at least one second sorbent, the at least one collector element receives the first regenerated fluid to concentrate, compress, condense, or capture the target species.

27. The method of claim 24, wherein one or more sorbents are connected in series after the at least one second sorbent and before the at least one collector element, wherein at least one third sorbent at a third capture temperature is configured to receive the second regenerated fluid from the at least one second sorbent, and the at least one third sorbent is configured to subsequently heat at a third regeneration temperature to generate a third regenerated fluid.

28. The method of claim 24, configured such that when a regenerated fluid produced from one sorbent at a regeneration temperature comes into contact with the next sorbent at a capture temperature, absorbed heat energy gained by the next sorbent is transferred or recycled back to a different sorbent or transferred to a thermal storage unit.

29. The method of claim 24, configured such that before a first regenerated fluid produced from one sorbent at a regeneration temperature come into contact to the next sorbent at a capture temperature, thermal energy of the regenerated fluid is transferred orrecycled back into the system or thermal storage such that a temperature of the regenerated fluid lowers towards the capture temperature of the contacted sorbent.

30. The method of claim 24, configured such that if the input fluid is at a higher temperature than a capture temperature of a contacted sorbent, thermal energy from a difference in an input fluid temperature and a sorbent capture temperature is transferred or recycled back to a different sorbent or transferred to a thermal storage unit.

31. The method of claim 24, configured such that before a regenerated fluid produced from one sorbent at a regeneration temperature comes into contact with the next sorbent at a capture temperature, the regenerated fluid contacts a heat exchanger element to lower the temperature of the regenerated fluid closer to a next sorbent capture temperature and energy transferred to the next sorbet is transferred or recycled back to another sorbent in the system or transferred to a thermal storage unit.

32. The method of claim 24, configured to set a temperature of one or more sorbents by flowing a heat exchange fluid, wherein the heat exchange fluid is air or liquid, that contacts passive or natural heat energy sources or heat sinks selected form the group consisting of ambient air, air at high elevation, underground earth, solar irradiation, waste stream byproduct from industrial processes, natural body of water and reservoir.

33. The method of claim 24, wherein the target species is water, carbon dioxide, hydrogen, nitrogen, oxygen, ammonia, methane, ethane, carbon monoxide, alcohol, sulfur dioxide, hydrogen sulfide, nitrogen oxide, or sulfur oxide.

34. The method of claim 24, wherein the input fluid is ambient air comprising water and / or carbon dioxide, flue gas containing water and / or carbon dioxide, compressed air, gas containing the target species, or liquid containing the target species.

35. The method of claim 24, wherein the process fluid pathway can be changed based on the temperature of and target species concentration in a process fluid such that the process fluid can bypass one or more sorbents and omit a sequential order of the one or more sorbents.

36. A method to capture target species from a fluid containing said target chemical species, the method comprising: receiving an input or process fluid comprising target chemical species with at least one sorbent that can be set to a capture temperature; heating the at least one sorbent to a regeneration temperature to generate a regenerated fluid; wherein the at least one sorbent is set to a capture temperature by exchanging heat with one or more temperature reservoirs and / or one or more temperature control elements coupled to one or more heat exchange elements that are coupled to one or more passive or natural heat sinks; wherein the at least one sorbent is set to a higher regeneration temperature by exchanging heat with one or more temperature reservoirs and / or one or more temperature control elements coupled to one or more heat exchange and / or heat collector elements that are coupled to one or more passive or natural heat energy sources; wherein the one or more temperature control elements that manage the heat exchange or heat transfer between the exogenous heat source or heat sink and the at least one sorbent.

37. The method of claim 36, wherein the passive or natural heat energy sources comprise air heat, solar irradiation, waste heat from industrial processes, underground earth heat, or a combination thereof.

38. The method of claim 36, wherein the passive or natural heat sinks comprise natural bodies of water, underground earth, ambient air at low or high elevation, or a combination thereof.

39. The method of claim 36, further comprising a plurality of sensors to monitor an input fluid temperature and a target species concentration and adjust a process fluid path of the input fluid and regenerated fluids to contact one or more sorbents or bypass and contact a collector element directly.

40. The method of claim 36, further comprising a plurality of sensors to monitor the temperature of the natural or passive heat energy sources and / or heat sinks and adjust the heat exchanged between the sorbent and the natural or passive heat energy sources and / or heat sinks.

41. The method of claim 36, further comprising one or more thermal storage elements that act as a temperature reservoir, set to a cold or hot temperature from exogeneous heat sources or heat sinks, which are capable to set the capture or regeneration temperature of the sorbent.

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