Direct air capture plant
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- REMOVR AS
- Filing Date
- 2025-11-28
- Publication Date
- 2026-06-04
Smart Images
Figure EP2025084759_04062026_PF_FP_ABST
Abstract
Description
[0001] DIRECT AIR CAPTURE PLANT
[0002] FIELD OF INVENTION
[0003] The present invention relates to the field of CO2 capture and storage, more specifically to a CO2-capture plant or system. The CO2-capture plant may be a direct air capture plant configured for large-scale CO2 capture and a plant for low concentration CO2 point source capture.
[0004] BACKGROUND
[0005] Direct capture of CO2 from a source gas, e.g. ambient air, also known as Direct Air Capture or DAC, has recently gained interest as a means to cut CO2 emissions or remove already emitted CO2 from the atmosphere and thereby combat climate change.
[0006] Some prior art DAC-systems or low concentration CO2 point source systems utilize one or more beds of porous sorbent particles to capture CO2 from the source gas. The captured CO2 can subsequently be released from the particles by manipulating the temperature and / or the partial pressure of the CO2 in the gas phase at the sorbent surface. The released CO2 may subsequently be stored in a manner preventing its release to the atmosphere or be used for e-fuels or other purposes to reduce CO2 emissions to the atmosphere.
[0007] To provide sufficient efficiency and operational flexibility, a CO2 capture system should preferably meet several criteria. Firstly, without any major modifications the system should be able to handle low- concentration sources of CO2, such as air, high-concentration sources of CO2, such as flue gas, as well as mixtures thereof. Low-concentration sources may have a CO2 concentration of up to 4 vol.%, preferably up to 2 vol.%. High-concentration sources may have a CO2 concentration above 4 vol.%. For a low-concentration source gas, such as ambient air, co-adsorption of CO2 from industrial sources may be utilized, to enhance efficiency. Secondly, the CO2 capture system should produce highly concentrated CO2, preferably comprising more than 80-90 vol.% of CO2, even from low-concentration source gasses. Thirdly, the possibility for the mixing of CO2 rich and CO2 depleted streams anywhere in the process should be minimised. Fourthly, the energy consumption of the CO2 capture system should be minimized. Finally, the capacity / size of the CO2 capture system should be easily scalable.
[0008] The two last criteria are especially important when applying the CO2 capture system for DAC, i.e. to capture CO2 from ambient air, or low concentration CO2 point source emissions, a process requiring the treatment of large gas volumes supplied by one or more fans. The work exerted by the fan(s) should preferably be minimized to minimize energy consumption. Furthermore, to reduce gas pressure losses in the bed(s) and thereby minimize energy consumption, the surface area “seen” by the incoming gas should be large, the gas flow velocity should be low, and the depth of the bed should be small. Additionally, the depth of the bed(s) may be scaled for the relatively small amounts of CO2 that are captured for a low-concentration source gas. Finally, the presence of H2O in the source gas will significantly reduce CO2 adsorption capacity of CO2-adsorbent beds, due to the tendency of water to bind to a physical adsorbent, such as zeolite.
[0009] NO 20221113 Al discloses a DAC-system in which H2O from an incoming source gas, e.g. ambient air, is removed by use of an enthalpy wheel. The use of enthalpy wheels is however not ideal for large- scale DAC-systems, as the size of the enthalpy wheels are restricted, at least due to costs large quantity and complicated interface.
[0010] The aim of the present invention is to provide an improved CO2 -capture plant.
[0011] SUMMARY
[0012] The present invention is defined by the appended claims and in the following:
[0013] According to a first aspect, there is provided a CO2 -capture plant for removing CO2 from a source gas. The CO2-capture plant includes a dehydration unit and a CO2 removal section. The CO2 removal section is configured to remove CO2 from a gas. The CO2 removal section comprises a dried air inlet, a CO2 depleted dry air outlet, and at least one CO2 adsorbent bed. The dehydration unit comprises a first H2O sorbent containment unit, a second H2O sorbent containment unit, a source gas inlet, a CO2 depleted humid air outlet, a dried air outlet connected to the dried air inlet and a CO2 depleted dry air inlet connected to the CO2 depleted dry air outlet. Each of the H2O sorbent containment units comprises a first side (alternatively a first interface allowing fluid communication to a first side of a H2O sorbent bed of the H2O sorbent containment unit) being selectively connectable to any of the source gas inlet and the CO2 depleted humid air outlet, and a second side (alternatively a second interface allowing fluid communication to a second side of a H2O sorbent bed of the H2O sorbent containment unit) being selectively connectable to any of the dried air outlet and the CO2 depleted dry air inlet, such that during use one of the first H2O sorbent containment unit and the second H2O sorbent containment unit operates in an adsorption mode by being in fluid communication with the source gas inlet and the dried air outlet to dehydrate a source gas entering the source gas inlet when the other of the first H2O sorbent containment unit and the second H2O sorbent containment unit operates in desorption mode by being in fluid communication with the CO2 depleted dry air inlet and the CO2 depleted humid air outlet to dehydrate a sorbent in the other of the first H2O sorbent containment unit and the second H2O sorbent containment unit.
[0014] This configuration allows for continuous operation of the CO2-capture plant, with one H2O sorbent containment unit dehydrating the source gas while the other is being regenerated. This improves the overall efficiency of the CO2 removal process by ensuring a constant supply of dried air to the CO2 removal section. The alternating operation of the two H2O sorbent containment units enables the plant to maintain a steady-state performance, minimizing downtime and maximizing CO2 capture capacity. Each of the H2O sorbent containment units comprises at least one H2O adsorbent bed. The cyclic nature of the dehydration process, where one unit adsorbs moisture while the other regenerates, provides several advantages. Firstly, it allows for optimal utilization of the sorbent material, as each unit undergoes a complete adsorption-desorption cycle. Secondly, it provides operational flexibility, allowing for maintenance or repairs on one unit without completely halting the dehydration process. Additionally, this configuration can accommodate variations in source gas humidity and flow rate by adjusting the cycle times or flow distribution and / or rate between the two units.
[0015] The continuous supply of dried air to the CO2 removal section is crucial for maintaining the efficiency of the CO2 adsorption process. By consistently providing air with a low dew point, the system prevents water vapor from competing with CO2 for adsorption sites in the CO2 removal section. This ensures that the CO2 adsorbent beds operate at their optimal capacity, leading to higher CO2 capture rates and improved overall plant performance.
[0016] Furthermore, the alternating operation of the H2O sorbent containment units allows for effective heat management within the system. The exothermic nature of the water adsorption process generates heat, which is captured and dissipated during the regeneration phase. This helps maintain a stable temperature profile throughout the dehydration unit, preventing temperature breakthroughs that could negatively impact the downstream CO2 removal process, as well as reducing the energy efficiency due to increased need of cooling.
[0017] Although the term "air" is used in relation to, e.g., the direct air capture plant, the dried air inlet, the dry air outlet, etc, in some examples it may be replaced by the word "gas". For example, the CO2-capture plant may be used to remove CO2 from a flue gas that may contain minor amounts of oxygen, and in this example the term "gas" may be more appropriate. While the techniques described herein are primarily focused on direct air capture applications, they may also be applied in other scenarios that require CO2 removal from another source gas. For instance, these methods may be utilized in industrial settings where CO2 needs to be separated from process gases, or in enclosed environments such as submarines or spacecraft where CO2 levels must be controlled, ft is noted that the dehydration unit of the CO2-capture plant may also be used independently in other applications where H2O is to be removed from air, such as building services (e.g. a ventilation or AC-system) where dehydration of spaces (rooms) is required.
[0018] The flexibility of the CO2-capture plant allows for adaptation to various gas compositions and CO2 concentrations, making it potentially suitable for a wide range of CO2 capture applications.
[0019] As used herein, the term "sorbent" may refer to a material capable of taking up and holding other substances by either adsorption or absorption. Sorbents may include both adsorbents and absorbents, where absorbents take up and retain other substances throughout their volume rather than just on the surface. As used herein, the term "adsorbent" or “sorbent” may refer to a material capable of attracting and retaining molecules of a gas, liquid, or dissolved solid on its surface through physical or chemical interactions. The process by which molecules adhere to the surface of the adsorbent is called adsorption. Accordingly, when operating in the adsorption mode, which may be referred to as an adsorption operational state, a H2O sorbent containment unit is configured to remove moisture from a source gas. The sorbent material within the unit may attract and retain water molecules from the gas stream, effectively dehydrating the source gas as it passes through. This process may continue until the sorbent material reaches a desired level of saturation (a certain loading capacity) or until predetermined operating parameters or time interval indicate a need to switch to desorption mode. Note that the certain loading capacity point can be determined by measuring certain operating parameters.
[0020] As used herein, the term "desorption" may refer to the process by which molecules previously adsorbed onto a surface are released back into the surrounding medium. In the context of the dehydration unit desorption occurs when the sorbent material releases the previously captured water molecules. When operating in the desorption mode, which may be referred to as a desorption operational state, a H2O sorbent containment unit is configured to release moisture from the sorbent material. The desorption process may be initiated by altering conditions such as temperature, pressure, or the composition of the gas flowing through the unit. During desorption, the sorbent material may release water molecules into the gas stream, effectively regenerating the sorbent for subsequent adsorption cycles. This process may continue until the sorbent material reaches a desired level of dryness (certain loading capacity that is less in value than during adsorption) or until predetermined operating parameters or time interval indicate a need to switch back to adsorption mode. Note that the certain loading capacity point can be determined by measuring certain operating parameters.
[0021] By having one H2O sorbent containment unit operating in an adsorption mode while the other operates in a desorption mode, the H2O sorbent containment units effectively operate dynamically and in parallel, allowing for continuous and efficient dehydration of the source gas. The H2O sorbent containment units may be said to be simultaneously in the adsorption mode and the desorption mode, such that adsorption takes place at the same time as desorption. The system may dynamically switch the operational modes of the units based on various parameters of the incoming source gas such as moisture content, partial pressure of moisture, temperature or flow rate, as well as predetermined time intervals. This dynamic switching may optimize the dehydration process, ensuring that each H2O sorbent containment unit is utilized effectively and preventing saturation of the sorbent material. Additionally, the parallel configuration may provide redundancy, allowing for maintenance or unexpected shutdowns of one unit without halting the entire dehydration process.
[0022] The dehydration unit may comprise a first set of dampers configured to selectively connect the first side to any of the source gas inlet and the CO2 depleted humid air outlet. The dehydration unit may comprise a second set of dampers configured to selectively connect the second side to any of the dried air outlet and the CO2 depleted dry air inlet. The dehydration unit may comprise the first set of dampers and the second set of dampers. The use of dampers allows for precise control of the gas flow direction through the H2O sorbent containment units, enabling efficient switching between adsorption and desorption modes. Note that the configuration of the dampers can be of many different sorts depending on dehydration unit size and configuration.
[0023] More than two sets of dampers may be provided. The dampers or sets of dampers may be fitted with corresponding actuators. Actuators may enable automatic operation of the dampers to selectively connect different sides to respective inlets or outlets. The actuators may be configured to provide rapid movement of the dampers, to reduce leakages of air and thereby improve energy efficiency of the plant. Each set of dampers and its associated actuator or actuators may form part of a flow direction changer unit. A flow direction changer unit may comprise a housing or framework within which the dampers are housed and into and out of which the source gas is routed.
[0024] When connecting the first and second sides to respective outlets or inlets, the set of dampers may seal the other. For example, if the first set of dampers connects the first side to the source gas inlet, the first set of dampers may seal the first side from the CO2 depleted humid air outlet.
[0025] The CO2 capture plant comprises at least one apparatus, such as a fan, that moves the air through the entire plant including the dehydration unit. More than one apparatus may be provided. The apparatus that moves the air through the plant may be termed a plant supply air fan. The fan may be fitted with means to change the air flow rate through the fan and thus the dehydration unit. The means to change the air flow rate may e.g. be controls or regulators for adjusting the fan shaft speed, adjusting the fan impeller pitch, bypassing more or less air, making more or less restrictions in the flow path or other means or a combination of these means. The changing of the flow rate through the water sorbent will affect how quickly the water sorbent will reach the desired loading capacity (saturation level or dryness level) and temperature profile. The flow rate through the dehydration unit can be used as a measured parameter for controlling of switching the dampers or as a parameter that can be adjusted to reach the desired dew point value and / or temperature value in the dried air outlet.
[0026] The dehydration unit and / or the CO2 -capture plant may comprise a control system for controlling the sets of dampers and / or the plant supply air fan. When the dehydration unit comprises a first set of dampers and a second set of dampers, the dehydration unit may comprise a control system configured to control the first set of dampers and the second set of dampers and / or the plant supply air fan. A control system enables automated operation of the dehydration unit and / or the CO2-capture plant, optimizing the switching between adsorption and desorption modes and / or adjusting the air flow rate through the dehydration unit based on monitored parameters. When the dehydration unit is part of the CO2-capture plant which may comprise a plant control system, the plant control system may be used for controlling the sets of dampers and / or the plant supply air fan. The control system (i.e. the control system of the dehydration unit or the plant control system) may be configured to control actuators associated with the first set of dampers and the second set of dampers and / or the plant supply air fan. The control system may be configured to receive input relating to a desired position or configuration of one or both of the first set of dampers and the second sets of dampers and / or the air flow rate value and to provide an output control signal for moving the dampers to their desired positions and / or regulating the desired flow rate value of the plant supply air fan based on the input. Alternatively, the control system may receive input relating to one or more parameters from one or more sensors, to determine a desired position or configuration of the dampers and / or inlet air fan flow rate, and to output corresponding control signals. The control signal may be a switching signal or a set point for controlling actuators or inlet air fan or other components associated with the dampers.
[0027] The control system may be configured to control sets of dampers based on parameters such as temperature, dew point temperature, flow rate, partial pressure, time elapsed since a previous control signal, a position of one or more other sets of dampers and / or one or more supply air fan or other components, or another parameter. The control system may be configured to control sets of dampers and / or supply air fan according to one or more predetermined settings, such as a minimum cycle time between changes. The control system may optimize its operation to meet certain goals, such as maximizing the amount of time between control signals. Such optimizations or goals may improve efficiency of the plant, while reducing maintenance.
[0028] The dehydration unit may comprise a plurality of temperature sensors. The temperature sensors may be arranged to detect a temperature increase of the source gas between the source gas inlet and the dried air outlet. This may allow for real-time monitoring of the dehydration process, enabling detection of breakthrough conditions, i.e. temperature or moisture breakthrough, and tailoring the timing of switching between adsorption and desorption modes for maximized efficiency.
[0029] Specifically, the control system may be configured to control the first set of dampers and the second set of dampers and / or plant supply air fan flow rate based on temperature measurements received from the plurality of temperature sensors. The control system may be configured to switch the first H2O sorbent containment unit and the second H2O sorbent containment unit between operating in adsorption mode and desorption mode and / or adjusting the plant supply air fan flow rate when or before the temperature of a source gas exiting the dried air outlet increases relative to the temperature of the source gas at the source gas inlet. This pre-emptive switching and flow rate adjusting strategy helps prevent breakthrough of moisture and heat into the CO2 removal section, optimizing the efficiency of the CO2 capture process. For example, the control system may be configured to determine a temperature profile and may be configured to predict or otherwise determine a time at which switching is to be performed or flow rate adjustment, based on the temperature profile. The plurality of temperature sensors may comprise a first temperature sensor arranged to measure the temperature of a source gas entering the source gas inlet. The first temperature sensor may be provided within the source gas inlet or may be provided outside of the source gas inlet, i.e. to measure a temperature of the source gas before it enters the system. The plurality of temperature sensors may comprise a second temperature sensor arranged to measure the temperature of a source gas exiting the dried air outlet. The second temperature sensor may be provided within the dried air outlet or may be provided directly outside the dried air outlet.
[0030] Monitoring the inlet temperature may provide a baseline for detecting temperature changes in the dehydration process, while monitoring the outlet temperature may allow for detection of breakthrough conditions and assessment of the dehydration efficiency.
[0031] The plurality of temperature sensors may comprise at least a third temperature sensor arranged in each of the first H2O sorbent containment unit and the second H2O sorbent containment unit. In other words, one third temperature sensor may be provided in the first H2O sorbent containment unit and another third temperature sensor may be provided in the second H2O sorbent containment unit. Multiple third temperature sensors may be provided in the first H2O sorbent containment unit and / or the second H2O sorbent containment unit. Where multiple third temperature sensors are provided in a H2O sorbent containment unit, these sensors may be arranged in a grid or array pattern throughout the H2O sorbent containment unit. This may enable temperature mapping across the units, and particularly across H2O sorbent beds of the units. The third temperature sensors may be placed at different depths within the H2O sorbent beds to track the progression of adsorption and desorption processes. The third temperature sensors may be in addition to the second temperature sensor or instead of the second temperature sensor.
[0032] Each of the first H2O sorbent containment unit and the second H2O sorbent containment unit may comprise at least one H2O sorbent bed. The H2O sorbent bed, which may be referred to as an adsorbent bed above, may provide the primary means of removing moisture from the source gas. The H2O sorbent bed may comprise at least one temperature sensor arranged to measure the temperature of a source gas passing through the sorbent bed. Each of the first H2O sorbent containment unit and the second H2O sorbent containment unit may comprise a heat sink arranged adjacent to the H2O sorbent bed, the heat sink being positioned between the H2O sorbent bed and the dried air outlet. The H2O sorbent bed may comprise at least two third temperature sensor arranged to measure a temperature gradient of the source gas passing through the sorbent bed. The heat sink may comprise at least two third temperature sensor arranged to measure a temperature gradient of the source gas passing through the heat sink. The H2O sorbent bed and / or the heat sink may comprise at least two third temperature sensors arranged to measure a temperature gradient of the source gas.
[0033] The plurality of temperature sensors may comprise a fourth temperature sensor arranged between the H2O sorbent bed and the heat sink. The heat sink helps manage the temperature increase associated with the exothermic adsorption process, improving the overall efficiency of the dehydration unit and the CO2-capture plant.
[0034] In an exemplary embodiment, sensors may be provided along a flow path of the source gas between an inlet and an outlet, including at least a first temperature sensor at an inlet, at least a second temperature sensor at an outlet along the flow path, and a plurality of third temperature sensors within a H2O sorbent containment unit. At least one third temperature sensor may be provided in a H2O sorbent bed, at least three third temperature sensors may be provided in a heat sink, and at least one fourth temperature sensor may be provided between the H2O sorbent bed and the heat sink.
[0035] The H2O sorbent bed, and optionally the heat sink, may be made up of a plurality of water sorbent cassettes or other alternative means for containing the sorbent such as open trays, or arranging the sorbent material in form of beads, pellets or coated on substructure (monolith). In other embodiments, the H2O sorbent bed and / or the heat sink may be a single unit.
[0036] The CO2 adsorbent bed may comprise a first side connected to the dried air inlet and a second side connected to the CO2 depleted air outlet. The CO2 adsorbent bed may in exemplary embodiments be made up of a plurality of CO2 sorbent cassettes, or the CO2 adsorbent bed may be a single unit. The CO2 sorbent cassettes may have the same dimensions as the water sorbent cassettes, when used in the dehydration unit. Using standardized dimensions for both H2O and CO2 sorbent cassettes simplifies manufacturing, transport, inventory management, and maintenance procedures. The CO2 removal section may comprise at least two CO2 adsorbent units that may switch between adsorption and desorption. Each CO2 adsorbent unit may comprise a CO2 adsorbent bed. Multiple CO2 adsorbent units allow for continuous operation, with one CO2 adsorbent bed adsorbing CO2 while the other is being regenerated.
[0037] The dehydration unit may comprise a first humidity sensor arranged to measure the humidity of a source gas entering the source gas inlet. Monitoring inlet humidity allows for adjustment of the dehydration process based on the moisture content of the incoming source gas.
[0038] The dehydration unit may comprise a first flow sensor arranged to measure the flow rate of a source gas entering the source gas inlet. Monitoring inlet flow rate allows for adjustment of the dehydration process based on the flow rate of the incoming source gas.
[0039] The control system may be configured to switch the first H2O sorbent containment unit and the second H2O sorbent containment unit between operating in adsorption mode and desorption mode, respectively, according to a variable time interval and / or a measured gas flow rate, the time interval being dependent on the measured temperature, gas flow rate and humidity of the source gas entering the source gas inlet. This adaptive switching and flow rate adjusting strategy optimizes the dehydration process based on real-time conditions, improving overall efficiency. According to a second aspect, there is provided a dehydration unit for a CO2 capture plant. The dehydration unit comprises a housing accommodating a fust H2O sorbent containment unit and a second H2O sorbent containment unit. The housing comprises an inlet for a source gas, an outlet for CO2 depleted humid air, an outlet for dried air and an inlet for CO2 depleted dry air. Each of the H2O sorbent containment units comprises a first side being selectively connectable by a first set of dampers to any of the inlet for a source gas and the outlet for CO2 depleted humid air, and a second side being selectively connectable by a second set of dampers to any of the outlet for dried air outlet and the inlet for CO2 depleted dry air, such that one of the first H2O sorbent containment unit and the second H2O sorbent containment unit may be in fluid communication with the inlet for a source gas and the outlet for dried air when the other of the first H2O sorbent containment unit and the second H2O sorbent containment unit is in fluid communication with the inlet for CO2 depleted dry air and the outlet for CO2 depleted humid air.
[0040] This standalone dehydration unit provides a modular solution for air dehydration that can be integrated into various CO2 -capture plants or other applications requiring efficient air drying.
[0041] The housing may comprise a channel extension at the outlet for CO2 depleted humid air, the channel extension being configured to direct CO2 depleted humid air exiting the outlet for CO2 depleted humid air, during use, in a direction away from the inlet for a source gas. The channel extension helps prevent mixing of the humid regeneration air with the incoming source gas, improving the overall efficiency of the dehydration process.
[0042] The dehydration unit may be configured for connection to a CO2 removal section to form a CO2 -capture plant. The CO2 removal section may be configured to remove CO2 from a gas, and may comprise a dried air inlet, a CO2 depleted dry air outlet, and at least one CO2 adsorbent bed. The outlet for dried air of the dehydration unit may be connected to the dried air inlet of the CO2 removal section. The inlet for CO2 depleted dry air of the dehydration unit may be connected to the CO2 depleted dry air outlet of the CO2 removal section. The CO2 adsorbent bed may be provided between the dried air inlet and the CO2 depleted dry air outlet of the CO2 removal section.
[0043] The standalone dehydration unit may comprise any of the features described in connection with the dehydration unit forming part of the CO2-capture plant.
[0044] BRIEF DESCRIPTION OF FIGURES
[0045] Embodiments of the invention will be described, by way of example, with reference to the following drawings, in which:
[0046] Fig. 1 is a schematic view of a dehydration unit according to the invention.
[0047] Fig. 2 is a perspective view of an exemplary dehydration unit according to the invention. Figs. 3a and 3b are perspective views of a H2O sorbent containment unit of the dehydration unit in fig. 2 during adsorption and desorption of water, respectively.
[0048] Fig. 4 is a schematic view showing an exemplary configuration of sensors in the H2O sorbent containment unit in figs. 3a and 3b.
[0049] Fig. 5 is a schematic view of an exemplary CO2 removal section for operable connection to the dehydration unit according to the invention.
[0050] Fig. 6 is a perspective view of a direct air capture plant featuring two dehydration units as shown in fig. 2 and a CO2 removal section as shown in fig. 5.
[0051] Fig. 7 is an expanded view of the two dehydration units in fig. 6.
[0052] Common reference numerals are used throughout the figures to indicate similar features.
[0053] DETAILED DESCRIPTION
[0054] As discussed above, there is a need for efficient and economically viable CO2-capture plants, in particular DAC plants configured for large scale direct air capture of CO2.
[0055] The present disclosure describes a direct air capture plant designed for large-scale CO2 capture from a source gas. The plant comprises two primary components: a dehydration unit 2 and a CO2 removal section 3. The CO2 removal section 3 is configured to remove CO2 from a gas, while the dehydration unit 2 is designed to reduce the moisture content of the source gas before it enters the CO2 removal section. The dehydration unit includes two H2O sorbent containment units 9a, 9b, each capable of operating in either an adsorption mode or a desorption mode. This dual-mode operation allows one unit to dehydrate the source gas while the other unit regenerates its sorbent material, enabling continuous operation and efficient utilization of the sorbent material. The CO2 removal section 3 includes at least one CO2 adsorbent bed 4a-c for capturing CO2 from the dehydrated gas. The configuration and operation of these components contribute to the plant's ability to efficiently capture CO2 on a large scale.
[0056] A dehydration unit 2 is shown schematically in Fig. 1. The dehydration unit 2 is configured to reduce the moisture content of a source gas, which in this example is air from an air source 40, before it enters a CO2 removal section 3. The air source 40 is, in this example, an external environment.
[0057] Air from the air source 40 enters the dehydration unit 2 via an inlet 2a and passes through a first flow direction changing unit 2b. The first flow direction changing unit 2b directs the air to one of a pair of H2O sorbent containment units 2c operating in an adsorbent mode, where the air is dehydrated. The air then passes through a second flow direction changing unit 2d, where it exits the dehydration unit and is directed to an inlet air fan 36 and a heat exchanger 2e before being sent to the CO2 removal section 3. The assembly comprising the dehydration unit 2, the inlet air fan 36 and the heat exchanger 2e may be termed a pre-treatment unit 1. Air from the CO2 removal section 3, which has been further dehydrated and has had CO2 removed, is returned to the dehydration unit 2, and passes through the heat exchanger 2e and the second flow direction changing unit 2d, where it is directed to the other of the H2O sorbent containment units 2c, which is operating in a desorbing mode to rehydrate the air and regenerate the sorbent. In the heat exchanger 2e, the air entering the CO2 removal section 3 is cooled by the air exiting the CO2 removal section 3. From the H2O sorbent containment unit, the air passes again through the first flow direction changing unit 2b, and is directed to an outlet 2f, for returning the air to the external environment 40. The air returned to the external environment 40 is CO2 free moist air.
[0058] Fig. 2 shows an exemplary dehydration unit 2 in a perspective wireframe view, so that the internal and external structure can be seen. The dehydration unit 2 comprises a housing 26 that accommodates various components and flow paths. The housing 26 includes a source gas inlet 11 (corresponding to inlet 2a in fig. 1) and a CO2 depleted humid air outlet 12 (corresponding to outlet 2f in fig. 1) on one end, and a dried air outlet 14 and a CO2 depleted dry air inlet 15 on an opposite end. The inlets and outlets, 11, 12, 14, 15 are formed from ducting.
[0059] The source gas inlet 11 is for receiving air or another source gas from a source such as source 40. The CO2 depleted humid air outlet 12 serves as an exit point for air that has undergone a CO2 removal processes and has been rehydrated. On the opposite end, the dried air outlet 14 allows for dehydrated or dried air to exit the unit 2 into a CO2 removal section, such as CO2 removal section 3. The CO2 depleted dry air inlet 15 allows re-entry of air that has been stripped of CO2 from a CO2 removal section, such as CO2 removal section 3. The source gas inlet 11 and humid air outlet 12 are separated by a division plate 27, while the dried air outlet 14 and the CO2 depleted dry air inlet 15 are separated by a division plate 30.
[0060] To facilitate dehydration and rehydration of air, the dehydration unit 2 includes a first H2O sorbent containment unit 9a and a second H2O sorbent containment unit 9b. The first H2O sorbent containment unit 9a and the second H2O sorbent containment unit 9b are identical in structure in this example and are positioned side by side within the dehydration unit 2. Each H2O sorbent containment unit includes a H2O sorbent bed (not shown in this example) comprising an H2O sorbent for adsorbing water from the source gas, as will described below in relation to Fig. 3.
[0061] Continuing with Fig. 2, the H2O sorbent containment units 9a, 9b are aligned at a first side 10 and a second side 13 of the containment units. The first side 10 of each H2O sorbent containment unit is configured to be selectively connected to either the source gas inlet 11 or the CO2 depleted humid air outlet 12, while the second side 13 is configured to be selectively connected to either the dried air outlet 14 or the CO2 depleted dry air inlet 15. This configuration allows one H2O sorbent containment unit to operate in an adsorption mode, dehydrating the source gas, while the other H2O sorbent containment unit operates in a desorption mode, regenerating its sorbent material.
[0062] A first set of dampers 18 (forming parts of the first flow direction changing unit 2b in fig. 1) is positioned between first side 10 of the H2O sorbent containment units and the source gas inlet 11 and CO2 depleted humid air outlet 12. The fust set of dampers 18 allow said selective connection to either the source gas inlet 11 or the CO2 depleted humid air outlet 12 and H2O sorbent containment units 9a, 9b. Air flow between the first set of dampers 18 and the H2O sorbent containment units is facilitated by a duct 31, which is separated into two by a division plate 28. The division plate creates one flow path from the dampers 18 to the first H2O sorbent containment unit 9a, and another flow path from the dampers 18 to the second H2O sorbent containment unit 9b. The division plate 28 divides the duct 31, which may be referred to as a transition duct perpendicular to the division plate 27 dividing the inlet and outlet, and such a configuration may allow for a large cross-sectional area, resulting in a low velocity and thus a low pressure drop.
[0063] The first set of dampers 18 comprises four independently operable dampers arranged as two pairs. Opening or closing the dampers of each set facilitates said selective connection. A first pair of first set of dampers 18 are in communication with the source gas inlet 11 and second pair of the first set of dampers 18 are in communication with the CO2 depleted humid air outlet 12. One damper of each pair of dampers is in communication with a respective H2O sorbent containment unit 9a, 9b via the duct 31. Accordingly, opening alternate dampers in each pair with the other remaining closed results in flow between the source gas inlet 11 and one of the H2O sorbent containment units and between the CO2 depleted humid air outlet and the other of the H2O sorbent containment units.
[0064] A second set of dampers 19 (forming parts of the second flow direction changing unit 2d in fig. 1) is located between the second side 13 of the H2O sorbent containment units and the dried air outlet 14 or the CO2 depleted dry air inlet 15. The second set of dampers 19 allows selective connection to either the dried air outlet 14 or the CO2 depleted dry air inlet 15. Air flow between the second set of dampers 19 and the H2O sorbent containment units is facilitated by a duct 32, which is separated into two by a division plate 29. The division plate 29 creates one flow path from the dampers 19 to the first H2O sorbent containment unit 9a, and another flow path from the dampers 19 to the second H2O sorbent containment unit 9b. The division plate 29 and the duct 32 are arranged in a similar manner to the division plate 28 and duct 31 between the first set of dampers 18 and the H2O sorbent containment units.
[0065] The second set of dampers 19 may comprise four independently operable dampers arranged as two pairs, as in the first set of dampers 18. Opening or closing the dampers of each set facilitates said selective connection. A first pair of the second set of dampers 19 is in communication with the dried air outlet 14 and a second pair of the second set of dampers 19 is in communication with the CO2 depleted dry air inlet 15. One damper of each pair of dampers is in communication with a respective H2O sorbent containment unit 9a, 9b via the duct 32. Accordingly, opening alternate dampers in each pair with the other remaining closed results in flow between the dried air outlet 14 and one of the H2O sorbent containment units and between the CO2 depleted dry air inlet 15 and the other of the H2O sorbent containment units. Air can therefore flow along different flow paths through the dehydration unit, thereby allowing the air to be passed over each of the H2O sorbent containment units selectively and dynamically. This configuration allows for the dynamic switching between adsorption and desorption modes for the H2O sorbent containment units 9a, 9b, enabling continuous operation of the dehydration unit 2, as will be described below.
[0066] Although not shown in Fig. 2, the first set of dampers 18 and the second set of dampers 19 are controlled by a control system. The control system is configured to control the operation of the dampers based on various parameters, such as the temperature or partial pressure of humidity of the source gas or the flow rate of the source gas, to optimize the performance of the dehydration unit 2. That is, to achieve the desired humidity (dew point) value and temperature value in the dried air outlet. This control system allows for precise control of the air flow through the dehydration unit 2, ensuring efficient operation and optimal utilization of the sorbent material in the H2O sorbent containment units 9a, 9b.
[0067] The dehydration unit 2, and specifically the sets of dampers 18, 19 are controlled by a control system so that two primary modes are in operation simultaneously. The primary modes are an adsorption mode and a desorption mode. In adsorption mode, a H2O sorbent containment unit removes moisture from the source gas, while in desorption mode, a H2O sorbent containment unit regenerates its sorbent material.
[0068] The control system manages the operation of the first set of dampers 18 and the second set of dampers 19 to alternate the modes of the first H2O sorbent containment unit 9a and the second H2O sorbent containment unit 9b. In other words, in one configuration, the first H2O sorbent containment unit 9a is in the adsorption mode and the second H2O sorbent containment unit 9b is in the desorption mode, while in another configuration, later on, the second H2O sorbent containment unit 9b is in the adsorption mode and the first H2O sorbent containment unit 9a is in the desorption mode.
[0069] The control system manages the operation of the inlet air fan 36 (or plant supply air fan) to adjust the source gas flow rate through the dehydration unit 2 to affect how quickly the water sorbent will reach desired loading capacity in both desorption mode and desorption modes and therefore may affect the timing and duration for each mode. In other words, in one flow rate, the time duration between switching between adsorption mode and desorption mode will be shorter than with a lesser flow rate.
[0070] When the first H2O sorbent containment unit 9a is in adsorption mode, the control system opens the dampers in the first set 18 that connect the source gas inlet 11 to the first side 10 of the first H2O sorbent containment unit 9a. Simultaneously, the dampers in the second set 19 that connect the second side 13 of the first H2O sorbent containment unit 9a to the dried air outlet 14 are opened. This configuration allows the source gas to flow through the first H2O sorbent containment unit 9a, where moisture is removed, and then exit as dried air.
[0071] Concurrently, the second H2O sorbent containment unit 9b is in desorption mode, and the control system opens the dampers in the second set 19 that connect the CO2 depleted dry air inlet 15 to the second side 13 of the second H2O sorbent containment unit 9b, and opens the dampers in the first set 18 that connect the first side 10 of the second H2O sorbent containment unit 9b to the CO2 depleted humid air outlet 12. This arrangement allows dry air to flow through the second H2O sorbent containment unit 9b, picking up moisture from the sorbent material, and then exit as humid air.
[0072] The control system may then switch the modes, by switching the dampers, so that the first H2O sorbent containment unit is in desorption mode, with dry air flowing through the first H2O sorbent containment unit 9a for rehydration, and so that the second H2O sorbent containment unit is in adsorption mode, with moist air flowing through the second H2O sorbent containment unit 9b for dehydration.
[0073] The control system may periodically switch the modes of the H2O sorbent containment units by adjusting the damper configurations. This switching may be based on various parameters such as time elapsed, temperature measurements, humidity levels or flow rates from sensors. For example, if temperature sensors detect a temperature increase at the dried air outlet 14, indicating reduced adsorption efficiency and / or temperature breakthrough, the control system may initiate a mode switch or adjustment of the source gas flow rate. Measurements in relation to temperature, source gas flow rate and humidity are described below in relation to Fig. 4. In exemplary embodiments, temperature sensors may be arranged to detect a temperature increase of the source gas before it exits the dried air outlet 14, such that a mode switch may be performed to avoid any increase in temperature of the source gas exiting the dried air outlet 14.
[0074] The control system may also adjust the flow rate, timing and duration of each mode based on the current operating conditions. For instance, if the source gas has a higher moisture content or higher temperature level, the control system may lower the duration of the adsorption mode (decrease the time between mode switches) or reduce the source gas flow rate to maintain optimal dehydration performance.
[0075] In some aspects, the dehydration unit 2 may include a separate control logic that can be placed in a standalone dedicated logic solver or in a plant overall logic solver (i.e. part of a control system). This control logic may be responsible for managing the operation of the dehydration unit 2, including the switching of the H2O sorbent containment units 9a, 9b between adsorption and desorption modes, the adjustment of the air flow through the unit, and the control of the cycle time. The control logic may be configured to optimize the performance of the dehydration unit 2 based on various parameters, such as the temperature, source gas flow rate, partial pressure and / or humidity of the source gas, the loading state of the sorbent material, and the heat saturation state of one or more heat sinks. The capacity control of the dehydration unit 2 can be achieved by adjusting the air flow through the unit, adjusting the cycle time, or a combination of both. For instance, if the humidity in the ambient air is high, the sorbent material in the H2O sorbent containment units 9a, 9b may become loaded quicker, and thus the cycle time may be shortened to reach the design output parameters. Conversely, if the air humidity and / or source gas flow rate are low, it may take longer for the sorbent material to reach the loaded state, and the cycle time may be extended to achieve the design output parameters. In some cases, the cycle time should not be less than a minimum specified cycle time to avoid excess wear and tear on mechanical equipment such as the dampers in the first set of dampers 18 and the second set of dampers 19.
[0076] An exemplary structure of the first H2O sorbent containment unit 9a and the second H2O sorbent containment unit 9b is shown in Fig. 3. Each H2O sorbent containment unit 9a, 9b comprises a plurality of water sorbent cassettes 20 arranged into several parallel configurations. The water sorbent cassettes 20 are rectangular in shape and stacked vertically within each containment unit. This forms a plurality of cassette arrays, each array providing a vertically arranged H2O sorbent bed. This arrangement allows for efficient air passage and maximizes the surface area for dehydration.
[0077] In other embodiments of the H2O sorbent containment units, each of the H2O sorbent beds are not made up of multiple subunits, i.e. cassettes, but may be e.g. a unitary H2O sorbent bed. The sorbent containment unit 9a, 9b may also be made up of other arrangements than cassettes to form H2O sorbent beds having a good flow area over / through the sorbent material. These arrangements may e.g. be open trays that are part of the installation where sorbent pellets, sorbent beads or sorbent coated sub-structures (monoliths) are placed inside to form the bed structure.
[0078] Stop plates are positioned between the first H2O sorbent containment unit 9a and the second H2O sorbent containment unit 9b, and between different arrays of cassettes, as well as on the outsides of the H2O sorbent containment units. The stop plates are configured to guide the airflow into the channels formed by the arrays of cassettes 20 and / or to ensure that the airflow is evenly distributed across the cassettes 20, thereby maximizing the efficiency of the dehydration process.
[0079] The sorbent material used in the cassettes 20 or the H2O sorbent beds of the H2O sorbent containment units can e.g. be zeolite 3 A, zeolite, alumina 4A, or silica gel. These materials have high adsorption capacity for water, making them suitable for use in the dehydration unit 2. The choice of sorbent material may depend on various factors, such as the specific operating conditions of the CO2-capture plant and / or the dehydration unit 2, the availability and cost of the sorbent material, and the desired performance characteristics of the dehydration unit 2.
[0080] The sorbent material may be in the form of beads or pellets packed in cassettes or trays or powder coated onto a substructure. In the case of bead-packed cassettes or trays, the beads of sorbent material may be contained within a cassette structure, which can be easily installed in and removed from the H2O sorbent containment units 9a, 9b. This allows for easy replacement of the sorbent material when necessary. In the case of powder-coated substructures, the sorbent material is coated onto a solid substructure, providing a large surface area for adsorption and potentially enhancing the performance of the dehydration unit 2.
[0081] A cross-section of an exemplary sorbent cassette 20 or an exemplary unitary H2O sorbent bed is schematically shown in Fig. 4. The channels in communication with e.g. the source gas inlet and dried air outlet during dehydration mode are also indicated, as are a plurality of sensors to illustrate their relative locations within the dehydration unit 2. Each cassette 20 or unitary H2O sorbent bed comprises a H2O sorbent bed 16 and a heat sink 17. The H2O sorbent bed 16 is designed to adsorb H2O from the source gas, while the heat sink 17 is configured to absorb the heat generated during the adsorption process. The water sorbent cassette 20, the unitary H2O sorbent bed, the H2O sorbent containment units 9a, 9b and / or the dehydration unit 2, includes a plurality of temperature sensors 21, 22, 23, 24 and a plurality of humidity sensors 33, 34, 35, 36 arranged at various points to monitor the temperature of the source gas as it flows between the source gas inlet and the dried air outlet. Alternative embodiments of the water sorbent cassette 20 or the unitary H2O sorbent bed may e.g. be configured without a heat sink or comprise two adjacent H2O sorbent beds 16. The water sorbent cassette 20 and the unitary H2O sorbent bed may alternatively be termed a sorbent-heat sink arrangement.
[0082] The heat sink material may be metallic, ceramic, plastic, rock, sand or any other suitable material that is capable of absorbing heat.
[0083] The first temperature sensor 21 is positioned at the source gas inlet to measure the temperature of the source gas entering the water sorbent cassette 20. This allows for real-time monitoring of the initial temperature of the source gas, which can be useful for adjusting the operation of the dehydration unit 2 based on the temperature of the incoming source gas. A first humidity sensor 33 is also provided in the source gas inlet.
[0084] The second temperature sensor 22 is located at the dried air outlet to measure the temperature of the source gas exiting the sorbent cassette 20. This enables the control system to monitor the effectiveness of the dehydration process by comparing the temperature of the source gas before and after it passes through the water sorbent cassette 20. A second humidity sensor 34 is also provided in the dried air outlet.
[0085] At least one third temperature sensor 23 is arranged in the sorbent bed. These temperature sensors 23 provide additional data on the temperature of the source gas within the H2O sorbent containment units 9a, 9b, which can be used to further optimize the operation of the dehydration unit 2. Three third temperature sensors 23 are depicted in the sorbent bed in this example.
[0086] A fourth temperature sensor 24 is arranged between the H2O sorbent bed 16 and the heat sink 17. This temperature sensor 24 allows for monitoring of the temperature gradient across the H2O sorbent bed 16 and the heat sink 17, providing valuable information on the heat transfer process during the adsorption and desorption cycles, which can be used for further optimizing the operation of the dehydration unit. A third humidity sensor 35 is also provided between the sorbent bed and the heat sink.
[0087] At least one further temperature sensor 23a may be provided in the heat sink. Three further temperature sensors 23a are shown in this example.
[0088] The arrangement of these temperature sensors and humidity sensors within the water sorbent cassette 20 enables comprehensive monitoring of the dehydration process. By measuring the temperature and / or humidity at various points, the control system can accurately track the progress of the adsorption and desorption cycles, adjust the operation of the dehydration unit 2 as needed, and ensure efficient and effective removal of H2O from the source gas. Although multiple temperature sensors are depicted here, in other examples fewer or more temperature sensors may be provided.
[0089] As shown, the H2O sorbent bed 16 can include multiple third temperature sensors 23 arranged to measure a temperature gradient of the source gas as it passes through the H2O sorbent bed 16. These temperature sensors 23 may be positioned at different locations within the H2O sorbent bed 16, allowing for the measurement of temperature differences across the length or width of the H2O sorbent bed 16.
[0090] Fig. 5 illustrates a schematic arrangement of the CO2 removal section 3 of the direct air capture plant 1. The CO2 removal section 3 is configured to remove CO2 from a source gas. The CO2 removal section 3 comprises a dried air inlet 7, a CO2 depleted dry air outlet 8, and at least one CO2 adsorbent bed 4. The CO2 removal section 3 includes multiple CO2 adsorbent beds 4, including a first CO2 adsorbent bed 4a, a second CO2 adsorbent bed 4b, and a third CO2 adsorbent bed 4c.
[0091] Each CO2 adsorbent bed 4a-c is configured to adsorb CO2 from the dehydrated air received from the dehydration unit 2. The CO2 adsorbent beds 4a-c each comprise a first side 5 connected to the dried air inlet 7 and a second side 6 connected to the CO2 depleted dry air outlet 8. The dried air inlet 7 receives dehydrated air from the dehydration unit 2, while the CO2 depleted dry air outlet 8 releases air that has been stripped of CO2 back to the dehydration unit 2.
[0092] In some cases, the CO2 adsorbent beds 4a-c may operate in a cyclic manner, alternating between adsorption and desorption modes. During the adsorption mode, a CO2 adsorbent bed adsorbs CO2 from the dehydrated air. During the desorption mode, the CO2 adsorbent bed releases the adsorbed CO2, allowing it to be captured and stored. This cyclic operation allows for continuous removal of CO2 from the air, enhancing the efficiency of the direct air capture plant 1.
[0093] The CO2 adsorbent beds 4a-c are arranged in a parallel configuration, allowing for simultaneous operation of multiple beds, and are made up of a plurality of CO2 sorbent cassettes. These cassettes may have the same dimensions as the water sorbent cassettes 20 used in the dehydration unit 2, allowing for a consistent and modular design across the direct air capture plant 1. Exemplary cassettes suitable for use in the CO2 removal section, as well as in the dehydration units, are disclosed in Norwegian patent application N020240808.
[0094] Fig. 6 shows a direct air capture plant 100, providing a comprehensive overview of the plant's structure and layout, while Fig. 7 shows an enlarged view of the dehydration units of the plant 100 in Fig. 6. The direct air capture plant 100 includes multiple components, each serving a specific function in the CO2 capture process. The primary components of the direct air capture plant 1 are the dehydration units and the CO2 removal section.
[0095] In this example, two dehydration units are shown, positioned on the left side of the direct air capture plant 100 and shown in more detail in Fig. 7, where they are labelled Unit A and Unit B. These units are responsible for removing moisture from the incoming air, preparing it for the CO2 capture process. The dehydration units are arranged in parallel, allowing for simultaneous operation and efficient utilization of the sorbent material. Source gas, e.g. air from the surroundings, is taken in from the lefthand side via inlet 11, and moist CO2 depleted air is expelled above the dehydration units in the same direction via a channel extension 25. In this manner, mixture of the source gas to be dehydrated and the moist air being expelled may be minimized or avoided.
[0096] The dehydration units connect to three CO2 removal sections on the right-hand side of the direct air capture plant 100 via fans and heat exchangers. On the far-right are shown refrigeration units and compressors, although these are obscured from view by the CO2 removal sections.
[0097] LIST OF REFERENCE NUMBERS
[0098] 1 pre-treatment unit
[0099] 2 dehydration unit
[0100] 2a inlet
[0101] 2b first flow direction changing unit
[0102] 2c H2O sorbent containment units
[0103] 2d second flow direction changing unit
[0104] 2e heat exchanger
[0105] 2f outlet
[0106] 3 CO2 removal section
[0107] 4 CO2 adsorbent bed
[0108] 4a first CO2 adsorbent unit 4b second CO2 adsorbent bed
[0109] 4c third CO2 adsorbent bed
[0110] 5 first side
[0111] 6 second side
[0112] 7 dried air inlet
[0113] 8 CO2 depleted dry air outlet
[0114] 9a first H2O sorbent containment unit
[0115] 9b second H2O sorbent containment unit
[0116] 10 first side
[0117] 11 source gas inlet
[0118] 12 CO2 depleted humid air outlet
[0119] 13 second side
[0120] 14 dried air outlet
[0121] 15 CO2 depleted dry air inlet
[0122] 16 H2O sorbent bed
[0123] 17 heat sink
[0124] 18 first set of dampers
[0125] 19 second set of dampers
[0126] 20 water sorbent cassettes
[0127] 21 first temperature sensor
[0128] 22 second temperature sensor
[0129] 23 third temperature sensor
[0130] 23a further temperature sensor
[0131] 24 fourth temperature sensor
[0132] 25 channel extension
[0133] 26 housing
[0134] 27 division plate
[0135] 28 division plate 28 division plate
[0136] 29 division plate
[0137] 30 division plate
[0138] 31 duct 32 duct
[0139] 33 first humidity sensor
[0140] 34 second humidity sensor
[0141] 35 third humidity sensor
[0142] 36 Inlet air fan 37 Flow measurement sensor
[0143] 40 air source
[0144] 100 direct air capture plant
Claims
CLAIMS1. A CO2 -capture plant (100) for removing CO2 from a source gas, the CO2 capture plant comprising a dehydration unit (2) and a CO2 removal section (3),- the CO2 removal section is configured to remove CO2 from a gas and comprises a dried air inlet (7), a CO2 depleted dry air outlet (8) and at least one CO2 adsorbent bed (4a-c); and- the dehydration unit (2) comprises a first H2O sorbent containment unit (9a), a second H2O sorbent containment unit (9b), a source gas inlet (11), a CO2 depleted humid air outlet (12), a dried air outlet (14) connected to the dried air inlet (7) and a CO2 depleted dry air inlet (15) connected to the CO2 depleted dry air outlet (8), wherein each of the H2O sorbent containment units comprises a first side (10) being selectively connectable to any of the source gas inlet (11) and the CO2 depleted humid air outlet (12), and a second side (13) being selectively connectable to any of the dried air outlet (14) and the CO2 depleted dry air inlet (15), such that during use one of the first H2O sorbent containment unit (9a) and the second H2O sorbent containment unit (9b) operates in an adsorption mode by being in fluid communication with the source gas inlet and the dried air outlet (14) to dehydrate a source gas entering the source gas inlet (11) when the other of the first H2O sorbent containment unit (9a) and the second H2O sorbent containment unit (9b) operates in desorption mode by being in fluid communication with the CO2 depleted dry air inlet (15) and the CO2 depleted humid air outlet (12) to dehydrate a sorbent in the other of the first H2O sorbent containment unit (9a) and the second H2O sorbent containment unit (9b).
2. A CO2 -capture plant according to claim 1, comprising a first set of dampers (18) configured to selectively connect the first side (10) to any of the source gas inlet (11) and the CO2 depleted humid air outlet (12), and a second set of dampers (19) configured to selectively connect the second side (13) to any of the dried air outlet (14) and the CO2 depleted dry air inlet (15).
3. A CO2 -capture plant according to claim 2, comprising a control system configured to control the first set of dampers and the second set of dampers.
4. A CO2-capture plant according to claim 3, wherein the dehydration unit (2) comprises a plurality of temperature sensors (21,22,23,24) arranged to detect a temperature increase of the source gas between the source gas inlet and the dried air outlet.
5. A CO2 -capture plant according to claim 4, wherein the control system is configured to control the first set of dampers (18) and the second set of dampers (19) based on temperature measurements received from the plurality of temperature sensors.
6. A CO2-capture plant according to claim 5, wherein the control system is configured to switch the first H2O sorbent containment unit (9a) and the second H2O sorbent containment unit (9b) between operating in adsorption mode and desorption mode when or before the temperature of a source gas exiting the dried air outlet increases relative to the temperature of the source gas at the source gas inlet.
7. A CO2-capture plant according to any of claims 4 to 6, wherein the plurality of temperature sensors comprises a first temperature sensor (21) arranged to measure the temperature of a source gas entering the source gas inlet.
8. A CO2-capture plant according to any of claims 4 to 7, wherein the plurality of temperature sensors comprises a second temperature sensor (22) arranged to measure the temperature of a source gas exiting the dried air outlet.
9. A CO2-capture plant according to any of claims 4 to 8, wherein the plurality of temperature sensors comprises at least a third temperature sensor (23) arranged in each of the first H2O sorbent containment unit (9a) and the second H2O sorbent containment unit (9b).
10. A CO2 -capture plant according to any of claims 3 to 9, wherein the dehydration unit (2) comprises a first humidity sensor arranged to measure the humidity of a source gas entering the source gas inlet.
11. A CO2-capture plant according to any of the preceding claims, wherein the dehydration unit (2) comprises a first flow sensor (37) arranged to measure the flow rate of a source gas entering the source gas inlet.
12. A CO2 -capture plant according to claims 7 and 10, wherein the control system is configured to switch the first H2O sorbent containment unit (9a) and the second H2O sorbent containment unit (9b) between operating in adsorption mode and desorption mode according to a variable time interval, thetime interval being dependent on the temperature, the humidity and the flow rate of the source gas entering the source gas inlet.
13. A CO2 -capture plant according to any of the preceding claims, wherein each of the first H2O sorbent containment unit (9a) and the second H2O sorbent containment unit (9b) comprises at least one H2O sorbent bed (16).
14. A CO2-capture plant according to claim 13, wherein each of the first H2O sorbent containment unit (9a) and the second H2O sorbent containment unit (9b) comprises a heat sink (17) arranged adjacent to the H2O sorbent bed, the heat sink being positioned between the sorbent bed and the dried air outlet (14), the plurality of temperature sensors may comprise a fourth temperature sensor (24) arranged between the sorbent bed and the heat sink.
15. A CO2-capture plant according to claim 13 or 14, wherein the H2O sorbent bed (16), and optionally the heat sink, is made up of a plurality of water sorbent cassettes (20).
16. A CO2-capture plant according to any of claims 13-15, wherein the sorbent bed comprises at least one temperature sensor (22) arranged to measure the temperature of a source gas passing through the sorbent bed.
17. A CO2-capture plant according to claim 16, wherein the sorbent bed comprises at least two temperature sensors (22) arranged to measure a temperature gradient of the source gas passing through the sorbent bed.
19. A dehydration unit (2) for a CO2 -capture plant according to any of claims 1-17, the dehydration unit comprising a housing accommodating a first H2O sorbent containment unit (9a) and a second H2O sorbent containment unit (9b), the housing (26) comprises an inlet (11) for a source gas, an outlet (12) for CO2 depleted humid air, an outlet (14) for dried air and an inlet (15) for CO2 depleted dry air, wherein each of the H2O sorbent containment units comprises a first side (10) being selectively connectable by a first set of dampers (18) to any of the inlet (11) for a source gas and the outlet (12) for CO2 depleted humid air, and a second side (13) being selectively connectable by a second set of dampers (19) to any of the outlet (14) for dried air outlet and the inlet (15) for CO2 depleted dry air, such that one of the first H2O sorbent containment unit (9a) and the second H2O sorbent containment unit (9b)may be in fluid communication with the inlet for a source gas (11) and the outlet for dried air (14) when the other of the first H2O sorbent containment unit (9a) and the second H2O sorbent containment unit (9b) is in fluid communication with the inlet for CO2 depleted dry air (15) and the outlet for CO2 depleted humid air (12).
20. A dehydration unit (2) according to claim 19, wherein the housing comprises a channel extension (25) at the outlet (12) for CO2 depleted humid air, the channel extension being configured to direct CO2 depleted humid air exiting the outlet for CO2 depleted humid air, during use, in a direction away from the inlet (11) for a source gas.