Exhaust gas capture system

Abstract

A flexible exhaust gas capture system, including a plurality of adsorption beds, each adsorption bed comprising an enclosed internal volume containing adsorbent material and a heat exchanger. The heat exchanger comprises a conduit arranged through the internal volume of the adsorption bed, such that heat energy may be exchanged between a fluid transported through the conduit and the adsorbent material of the bed. A corresponding method is provided for receiving exhaust gas into the system, during which the intake of exhaust gas may be switched between adsorption beds, so as to continuously receive exhaust gas into the system and cyclically regenerate saturated adsorption beds using heat transferred from the exhaust gas.

Description

[0001] EXHAUST GAS CAPTURE SYSTEM

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to an exhaust gas capture system for capturing various types of exhaust gases.

[0004] BACKGROUND

[0005] The need for effective exhaust gas capture systems is a critical component of global efforts to reduce harmful emissions and mitigate environmental and health risks. Depending on the type of fuel or feedstock used, exhaust gases can include carbon dioxide (CO2), nitric oxide (NO), nitrogen dioxide (NO2), nitrous oxide (N2O), sulfur dioxide (SO2), ammonia (NH3), and methane (CH4). These emissions contribute to various environmental and health concerns: CO2 and CH4 are major greenhouse gases driving climate change, N2O has a potent warming effect and depletes the ozone layer, NO and NO2 contribute to air pollution and respiratory diseases, SO2 leads to acid rain and lung irritation, while NH3 can react to form fine particulate matter, affecting air quality and human health. Effective capture and reduction of these pollutants are essential to protecting both the environment and public health.

[0006] Engines and combustion systems play a vital role across numerous industries, powering vehicles, machinery, and energy production. They are widely used in transportation (including cars, locomotives, and maritime operations), as well as in construction, and industrial manufacturing. While alternative fuels such as biodiesel, hydrogen, natural gas, and synthetic fuels are emerging as cleaner options, all combustion processes — regardless of the fuel used — produce emissions that can impact air quality, climate, and human health. Furthermore, some industrial and biological processes, such as wastewater treatment, anaerobic digestion, and agricultural activities, generate emissions even without fuel combustion. To address these challenges, there is a growing necessity for a modular emissions capture system capable of adapting to different fuel types and operational environments. A flexible and scalable approach would enableindustries to effectively reduce harmful emissions, including greenhouse gases and air pollutants, while aligning with national and global decarbonisation goals. By implementing such systems, sectors reliant on engines and other emissionproducing processes can minimise their environmental impact and contribute to a more sustainable future.

[0007] Emission capture typically relies on bulky, costly, and single-purpose systems like selective catalytic reduction (SCR) for NOx and carbon capture systems for CO2. These technologies face significant drawbacks due to their large size and complexity, their cost inefficiency, and their limited ability to capture multiple pollutants. To align with tightening regulations worldwide, the development of compliant, efficient, compact, and versatile emission capture systems is critical.

[0008] The above-mentioned gas capture systems are used across many different industries to meet tightening emissions targets and regulations. By providing a number of adsorption beds, a gas capture apparatus can cycle through multiple stages in the adsorption and regeneration process, often aided by the use of external temperature control and pressure adjustments. Such processes themselves are energetically costly, and require multiple modules for gas collection, bed heating, cooling, condensing and storage. The space required for a continuous gas capture system is significant, and considering its limited implementation in the transport sector so far, there is a clear need for a compact and energy efficient system.

[0009] In the field of diesel engines, there is a need for a compact, energy efficient gas capture system, applicable to a wide array of diesel engines in the industries above.

[0010] The above-mentioned capture systems are widely used across various industries to comply with increasingly stringent emissions regulations. A typical capture apparatus operates through a number of adsorbent beds, allowing for a continuous cycle of adsorption and regeneration. This process is often facilitated by external temperature and pressure adjustments. However, gas capture itself is inherently energy-intensive, requiring multiple integrated modules for gascollection (e.g. emission capture), bed heating (for regeneration stage), bed cooling (for adsorption stage), storage and even more. The spatial footprint of a continuous gas capture system can be substantial, posing a challenge for its implementation in space-constrained environments, particularly in the transport sector. Given these limitations, there is a clear need for a more compact, energyefficient system that can effectively capture and re-use emissions without compromising operational feasibility.

[0011] SUMMARY OF INVENTION

[0012] According to the present invention there is provided a system for capturing exhaust gases, the system including a plurality of adsorption beds. Each adsorption bed comprises an enclosed internal volume containing adsorbent material, and a heat exchanger. The heat exchanger comprises a conduit arranged through the internal volume of the adsorption bed, such that heat energy is exchanged between a fluid transported through the conduit and the adsorbent material of the bed during use. Each adsorption bed may comprise a cavity or outer shell for the cooling of the adsorption beds.

[0013] The bed system includes a first inlet for receiving an exhaust gas into the heat exchanger of a first adsorption bed, and a connector arranged between the heat exchanger of a first adsorption bed and the internal volume of a second adsorption bed. The connector may be a series of valves and / or pipes. Therefore, in use, exhaust gas that has passed through the heat exchanger of the first adsorption bed moves into the internal volume of a second adsorption bed for adsorption by the adsorbent material.

[0014] The apparatus utilises the heat from the exhaust gases to regenerate the adsorbent bed. The adsorbent bed may be a fixed bed adsorber or any housing configured to hold a volume of adsorbent material. The heat exchanger is configured to transfer heat from the collected dirty exhaust gas (DEG) into the volume of adsorbent material. The heat energy provided by the exhaust gas via the heat exchanger increases the kinetic energy of the adsorbed molecules, which eventually allows the molecules to overcome the adsorption forces binding themolecules to the adsorbent. These forces may be provided by dipole-ion, quadrupole-ion, or Van der Waals interactions. The adsorbent material heats up due to the transfer of heat from the DEG, resulting in the desorption of any adsorbed emissions on the bed. When an adsorbent bed approaches saturation, or after a preset time has passed, the exhaust gas may be directed to the inlet of the corresponding heat exchanger, in order to transfer heat to the corresponding bed, thus beginning a desorption stage.

[0015] The second adsorption bed may also include an inlet for receiving exhaust gas. In this embodiment, the system may include a connector arranged to connect the heat exchanger of the second bed to the internal volume of the first adsorption bed. Each bed may comprise a number of valves for connecting the heat exchanger of a bed to the adsorbent material of another bed.

[0016] The apparatus utilises the heat from exhaust gases to regenerate the adsorbent bed efficiently. The adsorbent bed can be a fixed-bed adsorber or any housing designed to contain a volume of adsorbent material. A heat exchanger is incorporated to transfer thermal energy from the collected hot dirty exhaust gas (DEG) to the adsorbent material, raising its temperature and initiating desorption. The heat energy supplied via the heat exchanger increases the kinetic energy of the adsorbed molecules, weakening the adsorption forces — such as dipole-ion, quadrupole-ion, and Van der Waals interactions — that bind the molecules to the adsorbent surface. As a result, the adsorbed gases are released, regenerating the adsorbent for subsequent adsorption cycles. To maintain continuous operation, when an adsorbent bed nears saturation or after predetermined cycle time, the system redirects the exhaust gas flow to another bed to begin a new adsorption phase. Simultaneously, the heat exchanger transfer energy to the saturated bed to facilitate regeneration. Flow control is managed via valves, ensuring efficient switching between adsorption and desorption cycles while optimising energy utilisation.

[0017] The system may include a controller (control module) arranged to switch the adsorption bed into which exhaust gas is received, thereby facilitating a sequential input of exhaust gas into the heat exchanger of each adsorption bed in the system.An inlet provided on each bed may be used to collect DEG into the corresponding heat exchangers of each bed. This allows for the system to be expanded to a plurality of adsorbent beds, in which multiple inlets provide exhaust gases to multiple adsorbent beds. The process is cyclical, such that once a bed approaches saturation, the inlet is switched, and the DEG is passed through a different heat exchanger in order to regenerate the saturated, or near-saturated, bed.

[0018] The system may include a storage tank. In this embodiment, each adsorption bed comprises an outlet valve arranged to selectively release desorbed emissions from the internal volume of the adsorption bed. The storage tank is connected to an outlet of each of the adsorption beds.

[0019] Once the adsorbed emissions are desorbed during the regeneration phase, they are directed to a storage tank for further utilisation or disposal, depending on the application. The stored emissions can be repurposed in various industrial processes or safely removed for alternative applications. For example, captured CO2can be reused in calibration gas mixtures, synthetic fuel production, urea and fertiliser manufacturing, chemical synthesis, as well as in the production of diesel and aviation fuels. Additionally, CO2can be permanently stored through geological sequestration, helping to reduce its impact on the environment.

[0020] The system may include a controller configured to control the inlet valve and outlet valve of each adsorption bed such that, in use, exhaust gas is received into the heat exchanger of the adsorption bed through the inlet valve, thereby transferring heat to the saturated adsorbent material to facilitate desorption of adsorbed emissions, the desorbed emissions then released from the internal volume of the adsorption bed through the outlet valve into the storage tank.

[0021] The system may include a compressor. The compressor is arranged between the plurality of adsorption beds and the storage tank. The compressor is configured to receive desorbed emissions from the outlet valve of an adsorption bed, compress the desorbed emissions, and direct the compressed emissions in the storage tank.The system may include a compressor positioned between the adsorbent beds and the storage tank. The compressor is designed to create a vacuum, facilitating the efficient transfer of desorbed gases into storage. Additionally, it compresses the gas into a liquid state, significantly reducing its volume compared to its gaseous phase. This not only maximises storage capacity but also enhances the overall compactness and efficiency of the system — particularly beneficial for applications in the transport sector, where space optimisation is critical.

[0022] The compressor may be connected to the storage tank, such that desorbed emissions are removed from the bed during the regeneration step and directed to the storage tank.

[0023] The compressor may assist the regeneration step in an adsorbent bed. In this embodiment, the compressor generates a pressure difference in the internal volume of each adsorption bed, thereby drawing out desorbed emissions. In other words, the compressor is configured to generate a pressure difference relative to the internal volume of a connected adsorption bed when the adsorption bed is undergoing desorption, thereby drawing out desorbed emissions in the adsorption bed, and facilitating desorption of adsorbed emissions from the adsorbent material therein.

[0024] The pressure differential provided by the compressor causes the adsorbed exhaust gas, or emissions, to become desorbed and also pulls them out of the bed and towards the storage tank.

[0025] The conduit of each heat exchanger may comprise at least one pipe provided through the adsorbent material of each adsorption bed.

[0026] The innermost section (which acts as a heat exchanger) may include cylindrical pathways through which hot gas flows during the desorption phase. The conduit of each heat exchanger may consist of one or more pipes integrated within the adsorbent material of each adsorption bed. The number of heat exchanger pipes can correspond to the number of concentric pathways filled with adsorbent material, ensuring efficient heat transfer during the desorption phase.The system may include a condenser. The condenser is arranged within the connector between the heat exchanger of the first adsorption bed and internal volume of the second adsorption bed. The condenser is configured to receive cooled exhaust gas from the heat exchanger of the first adsorption bed and remove water from the cooled exhaust gas. The condenser may be comprised in the path of all connectors between adsorption beds, such that when exhaust gas exits the heat exchanger of a one adsorption bed, the gas is directed to the condenser and then output to the inner volume of another adsorption bed.

[0027] The condenser may form, or be comprised in, a pretreatment stage of the system. According to aspects of the invention, therefore, there may be provided a system, including; a first adsorption bed and a second adsorption bed; each adsorption bed including an enclosed internal volume containing adsorbent material and a heat exchanger, the heat exchanger including a conduit arranged through the internal volume of the adsorption bed, such that heat energy is exchanged between a fluid transported through the conduit and the adsorbent material of the bed during use; and a pretreatment stage provided along a flow path between the heat exchanger of the first adsorption bed and the enclosed internal volume of the second adsorption bed; the pretreatment stage including a condenser, the condenser configured to cool exhaust gas passing through it. The pretreatment stage may further be provided along a flow path between the heat exchanger of the second adsorption bed and the enclosed internal volume of the first adsorption bed.

[0028] The pretreatment stage is arranged in the flow path between each heat exchanger of each adsorption bed and the adsorbent material of other adsorption beds. This allows for the exhaust gas to be treated before interacting with the adsorbent material in the cyclical bed system. The pretreatment stage is configured to receive exhaust gas after it has passed through the heat exchanger of one adsorption bed, cool and / or treat the hot exhaust gas passing through it, and then pass the cooled and / or treated gas to the internal volume of another adsorption bed.The pretreatment stage may include a rectifier unit. Exhaust gas passed from the heat exchanger of one adsorbent bed passes through the rectifier unit, and is then passed to the internal volume of another adsorbent bed. In this way, damage to the adsorbent material in the beds is reduced, extending the life of the adsorbent material. The rectifier unit also assists in capturing or treating waste gases and liquid by-products that are unsuitable for adsorption.

[0029] A coolant fluid may be circulated through the rectifier unit. The flow of a coolant within or around the rectifier promotes further cooling of the exhaust gas within the rectifier unit. The cooling of the exhaust gas below certain temperatures promotes extraction of condensates (for example, water) from the exhaust gas. Liquid by-products extracted from the exhaust gas via condensation may be stored in a condensate reservoir, connected to the rectifier unit. Since exhaust condensates typically form acidic solutions, the condensate reservoir may be dosed with an alkali to neutralise the acidic solution. This forms stable salts, such as sodium sulphites and nitrates. In this way, liquid by-products can be managed safely.

[0030] In some implementations, the pretreatment stage further includes a hydrogen peroxide tank, connected to the rectifier unit. In such implementations, the exhaust gas may be treated with H2O2 as it passes through the rectifier unit to induce oxidation of exhaust gases. For example, NO may be oxidised to NO2. These oxidised gases are more easily adsorbed in the adsorbent beds, and thus such treatment improving adsorption efficiency at the adsorption stage. In this way, the exhaust gas is conditioned for improved capture efficiency before entering the adsorption system.

[0031] The pretreatment stage may include a blower unit connected to the rectifier unit. The blower unit is configured to control the pressure within the rectifier unit. The blower therefore acts as a backpressure regulator, thereby maintaining adsorption performance and engine performance.

[0032] The system may further include a wastewater tank connected to the condenser. The wastewater tank is configured to store water removed by the condenser.The system may also include a reactor shell enclosing one or more of the adsorption beds. The reactor shell may also be referred to as a cavity and encloses the adsorbent material in the one or more adsorption beds. The connector of a first adsorption bed is configured to connect the heat exchanger of the first adsorption bed to both the internal volume of a second adsorption bed within the reactor shell and an inlet of the reactor shell. Therefore, the cooled exhaust gas is split into two or more streams, wherein at least one stream passes into the internal volume of the second adsorption bed, and at least one other stream passes into the reactor shell. This “splitting” of the exhaust stream into at least one portion that enters the reactor shell facilitates the cooling of the second adsorption bed.

[0033] In this way, the volume of adsorbent material is in thermal contact with the cavity or reactor shell. Therefore, heat energy in the adsorbent material is transferred to the cooler exhaust gas. Some of the cooler exhaust gas is passed to the adsorbent material of the bed for adsorption, while some of the gas may be passed to a corresponding cavity provided within the bed. While pipes are provided through the adsorbent material for transferring thermal energy from the gas to the adsorbent material, the adsorbent material may be provided within a cavity such that thermal energy can be exchanged from a hotter adsorbent material to a cooler exhaust gas. This facilitates the cooling of the adsorbent material, thereby promoting the adsorption of emissions after regeneration.

[0034] In this way, hot dirty gas passed though the heat exchangers can facilitate desorption in an adsorption bed, and cooler gas passed through the reactor shell can facilitate adsorption in a different adsorption bed.

[0035] The adsorbent material of each adsorption bed may comprise polar materials such as zeolites or activated carbon, MOFs, or any material suitable for adsorbing polar molecules. The polar molecules may include CO2, N2O, NO2, and NO, SO2, NH3 and CH4, which may be captured by the adsorbent material. Less polar molar molecules, such as N2 are not typically adsorbed.The adsorbent material of each adsorption bed may include a porous material with pore openings of 1-50A, preferably 10A.

[0036] Each adsorption bed may include a product valve configured to release clean exhaust gases, where clean exhaust gases are gases that are not adsorbed when passed through the internal volume of the adsorption bed. Put alternatively, the product valve is configured to release non-adsorbed gases.

[0037] According to a second aspect of the invention, a method is provided for capturing exhaust gases using a plurality of adsorption beds, each adsorption bed comprising a heat exchanger and an enclosed internal volume containing an adsorbent material. The method includes receiving an exhaust gas by a first inlet into the heat exchanger of a first adsorption bed, passing the exhaust gas through the heat exchanger of the first adsorption bed, and passing, by a connector, the cooled exhaust gas that has passed through the heat exchanger of the first adsorption bed to the internal volume of a second adsorption bed for adsorption.

[0038] The method may further include receiving the exhaust gas via a second inlet. The second inlet is arranged to receive an exhaust gas into the heat exchanger of the second adsorption bed, passing the exhaust gas through the heat exchanger of the second adsorption bed, and passing, by a connector, the cooled exhaust gas that has passed through the heat exchanger of the second adsorption bed to the internal volume of the first adsorption bed for adsorption.

[0039] The method may further include switching the receiving of exhaust gas into the first and second inlets, so as to sequentially receive exhaust gas into at the heat exchanger of each adsorption bed.

[0040] The method may further include a step of dividing the stream of cooled exhaust gas into two or more streams. At least one stream is passed to the internal volume of the second adsorption bed and at least one stream is passed to a reactor shell. The reactor shell encloses the second adsorption bed such that the stream of cooled gas facilitates the cooling of the second adsorption bed.The method may include passing the exhaust gas through a condenser after it has passed through the heat exchanger of the first adsorption bed. The condenser may be arranged between the heat exchanger of the first adsorption bed and internal volume of the second adsorption bed. In this embodiment, the method further includes receiving cooled exhaust gas from the heat exchanger of the first adsorption bed; and remove water from the cooled exhaust gas.

[0041] The method may further include switching the releasing of desorbed emissions from the internal volume of each adsorption bed to a storage tank through an outlet valve arranged on each of the adsorption beds.

[0042] The method may further include controlling the inlet valve and the outlet valve arranged on each of the adsorption beds such that exhaust gas is received into the heat exchanger of the second adsorption bed through the inlet valve of the second adsorption bed. This causes the adsorbent material contained within the inner volume to be heated, facilitating desorption of adsorbed emissions. The desorbed emissions are then released from the internal volume of the second adsorption bed through the outlet valve and into a storage tank.

[0043] The method may further include generating, by a compressor, a pressure differential in the internal volume of the second adsorption bed. This facilitates the desorption of adsorbed emissions from the adsorbent material therein and drawing out desorbed emissions. In this embodiment, the compressor is arranged between the plurality of adsorption beds and the storage tank. The compressor is further configured to receive desorbed emissions from the outlet valve of the second adsorption bed, compress the desorbed emissions, and direct the compressed emissions into the storage tank.

[0044] BRIEF DESCRIPTION OF DRAWINGS

[0045] Embodiments of the disclosure will now be described, purely by way of example, with reference to the accompanying figures, in which:

[0046] Figure 1 illustrates a schematic diagram of a gas capture system;Figure 2 illustrates a schematic diagram of an adsorption bed;

[0047] Figure 3 illustrates a workflow diagram showing a method according to embodiments of the present invention;

[0048] Figure 4 illustrates a workflow diagram showing a method according to embodiments of the present invention;

[0049] Figure 5 illustrates a schematic workflow diagram showing the path of exhaust gas through a section of the system, according to embodiments of the present invention;

[0050] Figure 6 illustrates a detailed workflow diagram showing a method according to embodiments of the present invention;

[0051] Figure 7 illustrates a schematic diagram of a pretreatment stage;

[0052] Figure 8a illustrates how the carbon dioxide capture rate varies for a single bed with different parameters;

[0053] Figure 8b illustrates how the nitrous oxide capture rate varies for a single bed with different parameters; and

[0054] Figure 8c illustrates the cyclical N2O (nitrous oxide) and CO2 capture rates during the adsorption and desorption phases of a single adsorption bed.

[0055] DETAILED DESCRIPTION

[0056] According to the present invention, a system is provided in which a number of adsorption beds are operated for capturing pollutants from exhaust gases in a cyclical process. The energy efficiency of the system is maximised through the strategic placement of the exhaust gas flow path, which promotes thermal energy transfer between the gas and the adsorbent material in the beds. This invention reduces the need for external heating components (which are typically found in prior art systems, such as temperature swing adsorption systems), which in turn reduces the energy consumption of the system and allows for compactimplementation. By reducing the size of the system, the gas capture system becomes more applicable to implementations on locomotives and ships, in which space is often scarce.

[0057] Figure 1 illustrates a multi-pollutant gas capture system 100 according to an embodiment of the present invention. The system comprises two adsorption beds, bed 1 110’ and bed 2 110, each adsorption bed comprising an enclosed internal volume 130, 130’ containing adsorbent material 140, 140’ and a heat exchanger 120, 120’. The heat exchanger 120 comprises one or more pipes arranged through the internal volume of the adsorption bed 110, such that heat energy may be exchanged between a fluid transported through the pipes and the adsorbent material 140 surrounding the pipes within the bed. Each adsorption bed 110 comprises an inlet A, A’ for receiving hot dirty exhaust gas into the heat exchanger 120, 120’ of the corresponding bed.

[0058] Each adsorption bed 110 may comprises an adsorption array 200 as illustrated in Figure 2, comprising a plurality of individual cylinders 230, each surrounding a pipe 220 of the heat exchanger and containing adsorbent material 230, as described in more detail below. Returning to Figure 1, for each bed 110, 110’ a set of connections (referred to herein equally as “connectors”), in the form of piping or any other form of conduit, and potentially other system components such as valves, are arranged to provide fluid communication between the heat exchanger of the bed and the internal volume of the other bed, such that the DEG after passing through the heat exchanger of one bed is passed to the internal volume of another bed for adsorption. The connection between adsorption bed 1 110’ comprises the fluid flow route including feed valve FV 1, connection B to the condenser 150, through another feed valve FV 3 and connection C and into inlet valve IV2 of adsorption bed 2. Similarly, the connection providing the fluid flow route from the heat exchanger 120 of bed 2 110 to the internal volume of bed 1 110’ comprises feed valve FV 2, connection B, the condenser 150 feed valve FV3 and inlet valve IV 1. This allows the fluid, after flowing through the heat exchanger of one bed, to be passed through the feed valves FV 1, FV 2, through the condenser 150, and then to the internal volume of the other bed 110, 110’ via thecorresponding inlet valve IV 1, IV 2 for adsorption. By controlling these valves, the flow of the dirty exhaust gas, DEG, can be directed through the heat exchanger 120’ of a first bed to the internal volume 130 of a second bed before being switched to be directed through the heat exchanger 120 of the second bed and into the internal volume 130’ of the first bed.

[0059] The use of multiple beds in this system performing reciprocal processes allows for a continuous, cyclical process for gas capture. The gas received into the heat exchanger 120 of one bed facilitates the regeneration of that bed, while the other bed is used for adsorption. During this reciprocal cycle, the operation of each bed 110, 110’ switches between adsorption and regeneration.

[0060] In Figure 1 , a flow distributor 103, 103’ at the inlets A, A of each heat exchanger splits the flow of hot exhaust gas into the heat exchanger conduits 120, which are arranged longitudinally through the adsorbent material within the bed, at equal spaces from each other. Along the length of the conduits, a number of connecting conduits are provided laterally across the adsorption bed 110, connecting the longitudinal pipes. Due to this arrangement, a fluid can flow evenly throughout the heat exchanger arrangement within the adsorbent material. The adsorbent material 140 is packed around the conduits so as to enclose them, allowing for optimal heat transfer from the hot dirty exhaust gas (DEG) directed through the heat exchanger arrangement to the adsorbent material 140. The heat exchanger conduits 140, 140’ may be arranged so as to maximise the surface area between the conduits and the surrounding adsorbent material.

[0061] In typical heat exchangers, water or oil is passed through pipes to transfer heat with the adsorbent material. This requires an external heat source, and thus an external energy source. The present invention utilises heat energy from the exhaust gas itself to heat the adsorbent beds either alone or to supplement a further heat supply, thereby significantly reducing the energy required to power the adsorption cycle. The hot exhaust gas may be collected from an engine. By passing the hot exhaust gas through the conduits of one bed, the heat energy of the exhaust gas is transferred to the adsorbent material in the bed, heating up the adsorbent material and facilitating the desorption process. Additionally, afterpassing through the heat exchanger 120, 120’, the hot exhaust gas enters the condenser 150, where it is cooled and dried. This conditioned gas is then directed into another adsorption bed 110, 110’, with a portion flowing through the internal volume containing the adsorbent material for pollutant capture. As will be described below, with reference to Figure 2, a portion of the cooled gas leaving the condenser may be used for cooling the adsorption bed to regulate the temperature and maintain adsorption efficiency. In particular, as shown in Figure 2 the adsorbent material 230 may be contained within a plurality of cylinders (or “housings” more generally) 240 within the enclosed internal volume of the bed, defined by an outer shell 250. A portion of the cooled DEG from the condenser may be passed around the cylinders 240 to regulate the temperature, while the majority of the cooled DEG is passed into the cylinders for adsorption. This secondary flow helps regulate the temperature of the adsorbent volume, ensuring optimal conditions for the adsorption stage.

[0062] As described above, the high temperature dirty exhaust gas (DEG) is passed through the heat exchanger pipes 120 to meet the heat requirement of desorption in the bed. The bed temperature rises continuously, and desorption occurs. The adsorbate is released from the bed 110 and flows through the desorbed valve DV 1 , DV 2 for compression and storage.

[0063] Each of the valves or inlets described herein may be operated in an automated manner by a control module to provide a required system cycle. These valves include the DEG inlets A, A, feed valves FV, inlet valves IV, desorbed valves DV, product valves PV, and purge valves arranged on each bed. The control module may detect that a given bed is approaching saturation, or the control module may be set to switch the intake of gas into the bed after a preset time. In this implementation, the adsorption bed phase may transition based on when the entire volume of the adsorbent has made contact the exhaust gas. As described further below, Figure 8a and 8b, illustrate the capture rate of a single adsorption bed for CO2and N2O respectively. The capture rate is high for a period of time until the adsorbent material approaches saturation and the adsorption rate declines. The control module may be configured to switch the flow of DEGbetween adsorption beds to maintain optimum capture efficiency. The residence time of the DEG within the adsorption bed while maintaining maximum capture efficiency varies depending on the parameters of the system, such as the mass of adsorbent material and the DEG flow rate and therefore the timing of the switching of the valves may be selected depending on the specific properties of the system to ensure optimum capture efficiency.

[0064] Figure 8c illustrates the amount of CO2and N2O captured within a single adsorption bed over time. The amount of exhaust gas increases steadily in the adsorption phase of the bed, before reducing more rapidly during heating and desorption, thereby producing the cyclical sawtooth curve illustrated. The control module is configured to continue to maintain a flow of DEG into the internal volume of the adsorption bed during the adsorption phase (in this case around 1000 seconds) before closing the inlet valve IV, opening the inlet A to allow hot DEG to enter the heat exchanger inducing desorption and opening the desorbed valve DV to direct the desorbed gas into the compressor 160 and storage tank 162.

[0065] The control module may switch the inlets and valves between an open or closed position, in order to allow gas to pass through it or to block it from passing, respectively. The open and close positions of each valve or inlet may correspond to the phase that the bed is currently operating in; some example phases are described herein. For example, in the regeneration phase of Bed 1 may be configured as the inlet A, the feed valve FV 1 , and the desorbed valve DV 1 open, while the other valves are closed. In some examples, the system may comprise one or more sensors configured to determine the status of a bed, for example to determine the current saturation level, and the control module may be configured to operate the valves based on the operation status of the bed. In some examples, the control module may be configured to operate one or more valves based on a timer, for example to provide a required residence time as described above.

[0066] The receiving of exhaust gas may be switched between inlet A and inlet A to facilitate the regeneration step of each bed. The switch may be operated by the control module when a threshold is met.Figure 1 also illustrates a condenser module 150, which is connected to each adsorption beds via feed valves FV 1 and FV 2. The condenser module 150 may use a cooling medium to cause water to condense out of the exhaust gas. The cooling medium in this example may be air, water, or other suitable coolant. The wet exhaust gas is cooled using the cooling medium, such that water vapour reaches its dew point. Water vapour condensed from the gas may be separated from the gas using a demister. Water droplets form on the demister or the walls of the condenser and are drained away. The drained water is stored in a wastewater tank 152. In other embodiments, the water may simply be disposed of.

[0067] As shown in Figure 1, the adsorption beds 110, 110’ are interconnected with a purge valve 170. The purge valve 170 may be used to assist the beds 110, 110’ to balance their pressure once switching between adsorption and desorption. In common gas capture systems, hot steam is passed through the bed, flushing the bed of any excess adsorbate after a prolonged period of usage. The purge valve is closed during regular, cyclical operation of the system 100.

[0068] When cooled, dry gas is passed to an adsorption bed 110, 110’, some non-polar gases 104 may not be adsorbed by the adsorbent material 140, 140’. These nonpolar gases 104 may be released by the corresponding product valve PV 1 , PV 2 at point D after passing through the bed.

[0069] The adsorbent material in each adsorption bed may be a porous cubic lattice structure. The pore openings are approximately 10 A. Negative salt cations within the framework generate strong electrostatic fields, enhancing the adsorbent’s ability to trap emissions. These materials are particularly effective for adsorbing these exhaust gases, but other adsorbed materials may be used such as Metal-Organic Frameworks (MOFs), Zeolites, Activated Carbons (ACs), mine-Functionalized Adsorbents, Metal Oxides, Carbon Nanotubes (CNTs).

[0070] In the desorption or regeneration stage, the heat from the heat exchanger of the bed and the pressure vacuum caused by the compressor increases the kinetic energy of the adsorbed molecules, overcoming physical adsorption forces like dipole-ion, quadrupole-ion, and Van der Waals interactions, thereby favouringdesorption by reducing pressure and gas concentration within the bed. In this way, both the heat transferred to the adsorbent material from the DEG in the heat exchangers facilitates desorption in addition to the pressure difference caused by the compressor.

[0071] In the embodiment shown in Figure 2, the heat exchanger pipes 220, referred to herein as conduits, are provided longitudinally throughout the bed 200, which may take the form of an adsorption array 200 comprising a plurality of sub-chambers or cylinders 240. A cylinder 240 comprising adsorbent material 230 encloses each conduit 220. The adsorbent material 230 may be surrounding the heat exchanger conduit 220, maximising heat transfer. In this arrangement, each heat exchanger conduit 220 and the cylinder or sub-chambers 240 enclosing the adsorbent material 230 are concentric. In each adsorption bed 200, several pipes and conduits are provided, contained within a housing or shell 250 to form an “adsorption array”. The adsorption capacity of each bed 200 increases with the volume of adsorbent material 230 provided within it.

[0072] Typically, an adsorption array 200 consists of an array of three distinct sections designed to optimise gas adsorption and desorption. The innermost pipeline section 220 (providing the heat exchangers) features a cylindrical conduit through which hot gas 202 flows during the desorption phase. Surrounding this is a concentric volume filled with adsorbent material 230, where the actual gas capture occurs. The adsorbed material 230 may be contained within this volume by the sub-housings or cylinders 240. Between these cylinders 240, but within the shell 250 there is a cavity through which dried, cooled exhaust gas 206 may circulate, helping to regulate the temperature of the solid adsorbent and prevent overheating during adsorption.

[0073] Before entering the adsorbent-containing section, the gas flow 204 is evenly distributed through a flow distributor to enhance the efficiency of the adsorption process. Also, another flow distributor is used to direct hot dirty exhaust gas into the heat exchanger pipeline 220, facilitating the desorption process. Once a bed reaches full adsorption capacity, the system automatically switches the gas flow to a new bed to initiate a fresh adsorption cycle. Simultaneously, the first bedundergoes regeneration (or desorption), ensuring continuous operation. The flow paths within the internal heat exchanger pipeline 220, the concentric adsorbent-filled cylinders 240, and the cavity 250 are precisely controlled using valves. These valves regulate the switching between beds, ensuring that adsorption and desorption occur efficiently and in a synchronised manner.

[0074] It should be noted that in the adsorption phase, the portion of exhaust gas 204 and the portion of exhaust gas 206 may flow simultaneously in a given bed, but in this phase, the hot, dirty exhaust gas 202 is not present in the bed. Accordingly, when the hot, dirty exhaust gas 202 is directed through the inner heat exchanger pipeline 220 (during the regeneration phase), there is no gas flow 204, 206 through the concentric adsorbent-filled sections 240 or the cavity 250. In an example, 10% of the gas stream passes through the cavity within the outer shell 250 exchanging heat with the adsorption arrays to cool them and enhance adsorption efficiency. Simultaneously, 90% of the gas flows within the cylinders 240 in contact with the adsorbent material, where pollutants are captured, and the temperature rises as adsorption occurs.

[0075] Hot exhaust gas 202 may be collected from an engine, and input into the heat exchanger conduits. The exhaust gas 202, while flowing through the conduits 220, transfers heat energy to the adsorbent material 230 surrounding the conduits 220.

[0076] Each adsorption bed 200 may comprise a cavity 250 in which the adsorbent material, pipes, and heat exchanger conduits are provided. The cavity may comprise a separate inlet for receiving cooled gas. In this way, a portion of the cooled exhaust gas, after passing through the condenser, may be directed into the reactor shell. The cooled gas facilitates the transfer of heat energy out of the adsorption bed. This helps maintain a constant temperature in the bed during adsorption. During this cooling process, other portions of exhaust gas may be directed into the pipes 240 comprising adsorbent material 230. Therefore, some portions of gas 204 are adsorbed in the corresponding adsorbent material and other portions of gas 206 are directed into the reactor shell in order to cool the adsorbent material.The gas capture apparatus, when in use, may initially receive a stream of exhaust gas at inlet A.

[0077] The following describes the cyclical operation of two adsorption beds, during which Bed 1 110’ initially operates in an adsorption phase (capturing exhaust gas molecules) while Bed 2 110 is initially saturated with adsorbate, thus operating in a regeneration phase (desorbing adsorbed molecules). The beds sequentially switch between phases, which may include the redirecting of the incoming stream of exhaust gas into the heat exchanger of the saturated adsorption bed in order to heat up the bed, facilitating desorption of the adsorbate from the material. The desorbed emissions can then be removed from Bed 2, compressed, and stored.

[0078] In other words, Bed 2 is saturated with adsorbed emissions, while Bed 1 is empty. The process begins with the reception of hot dirty exhaust gas (DEG) at inlet A (102). The hot DEG enters the heat exchanger 120 of Bed 2, transferring heat to the adsorbent material 140 in Bed 2. This recovered thermal energy releases emissions trapped in Bed 2. During this stage, product valve PV 2 and inlet valve IV 2 remain closed.

[0079] A stream of hot, dirty exhaust gas (DEG) is directed from an engine or exhaust stream into the apparatus, through the operatable inlet A. In Figure 1, a grid of longitudinal and laterally arranged conduits are provided within the material, and the adsorbent material is arranged surrounding the conduits. The DEG flows through the grid of conduits.

[0080] In this arrangement, heat energy is transferred to the volume of adsorbent material 140 surrounding the conduits, heating the material up. It is known that adsorption affinity generally decreases with increasing temperature, since the binding energy of adsorbed molecules is overcome by their increased kinetic energy. Due to the increased temperature, therefore, the desorption of molecules from the material is promoted. The desorbed emissions exit the adsorption bed via desorbed valve DV 2. In this way, the adsorption bed 110 is regenerated over time for further adsorption in a subsequent iteration of the gas capture cycle.After passing through the heat exchanger pipes 120, the cooler DEG flows to feed valve FV 2 and into a condenser 150 at point B. In the condenser, water vapor, with its higher condensation temperature, is separated from the DEG and collected in a wastewater tank 152. The removal of water from the gas can increase the yield of less polar molecules and slow the degradation of the adsorbent material 140.

[0081] After the exhaust gas is processed by the condenser 150, the dry exhaust gas exits the condenser module through feed valve FV and is passed to the other bed: Bed 1. The cooled and dried DEG proceeds to point C, entering Bed 1 through the corresponding inlet valve IV 1 while the desorbed valve DV 1 remains closed. In embodiments with more than two beds, the dry exhaust gas may be passed from the condenser to a third bed, such that the gas capture system operates in a cycle of more than two beds.

[0082] The dry exhaust gas enters Bed 1 through the inlet valve IV 1. A connector module comprising the condenser 150 is arranged between the feed valve FV 2 and inlet valve IV 1 and may be configured to distribute the gas across the cross-section of the adsorbent material in the bed. In other embodiments, the connector may not comprise the condenser 150 and may simply be the inlet valve IV 1. In other embodiments, the connector is comprised between the condenser 150 and the inlet valve IV 1. Each bed may be connected to a corresponding connector for the same purpose.

[0083] During the regeneration phase of Bed 2, the desorbed emissions released from the adsorbent material 140 of Bed 2 exits through the desorbed valve DV 2. The emissions are compressed by a compressor 160 and then collected in an emission storage tank 162. In Figure 1, the desorbed gas exits via desorbed valve DV 2 and arrives at the compressor 160.

[0084] After regeneration, the adsorbent material 140 may be hot due to flow of hot DEG through the corresponding heat exchanger 120. In order to begin efficiently adsorbing emissions again in the adsorption phase, the temperature of theadsorbent material 140 must decrease, since rate of adsorption typically increases with decreasing temperature.

[0085] At this stage, the DEG intake at inlet A ceases in order for cooling to begin in Bed 2. This represents a transition in phase, from the regeneration (or desorption) phase to a cooling or adsorption phase of Bed 2.

[0086] In further embodiments, during this cooling or adsorption phase, the connector module may divide the cool exhaust stream from the condenser 150 into multiple streams before arriving at Bed 1 through the inlet valve IV 1. A number of streams are directed to the adsorbent material of Bed 1. A number of streams are also input into a shell or cavity surrounding the adsorbent material in the bed. In this way, some of the cooled exhaust gas is not adsorbed by the adsorbent material but instead is used to facilitate cooling of the adsorbent material. In Figure 2, the reactor shell 250 surrounding the volume of adsorbent material 230 is shown, where cooler exhaust gas is permitted to flow in thermal contact with the adsorbent material 230. Heat energy is transferred from the adsorbent material 230 to the gas, which may then be recirculated for adsorption or disposed of. This process speeds up the cooling of the adsorbent material 230, allowing it to begin efficiently adsorbing exhaust gas earlier.

[0087] After Bed 1 has accumulated enough adsorbate, the bed transitions to the regeneration phase of the cyclical process. The threshold at which the bed transitions is not limited herein. The bed may begin regeneration when it is detected that the adsorbent material 140’ is approaching saturation. This may be detected by a decreasing rate of adsorption. In alternative implementations, Bed 1 may begin to regenerate after a preset residence time, which is based on the volume and shape of the adsorption bed. It is important to recognise that the foregoing steps occur also in Bed 2, since the process is cyclical.

[0088] In the embodiment illustrated in Figure 1, for example, Bed 1 approaches saturation, or the residence time has passed. Upon detection, the collected DEG from the engine or exhaust stream is directed through the inlet at point A (102’), entering the heat exchanger pipes 120’ in the adsorption bed. The redirection ofthe DEG through inlet A’ may occur at the same time as the blocking of DEG through inlet A, such that the system is continuously receiving exhaust gas through at least one inlet.

[0089] The heat exchanger pipes 120’ in Bed 1 transfer heat energy from the exhaust gas to the adsorbent material 140’, thus heating the adsorbent material 140’. As the adsorbent material 140’ heats up, gas molecules adsorbed in the material become desorbed. The desorbed valve DV 1 of Bed 1 is opened, and desorbed emissions exit the bed through the valve for compression by the compressor 160 and then storage or further processing.

[0090] In further embodiments, the compressor 160 provides a pressure difference between Bed 1 and the storage tank 162. By generating a lower pressure on the output side of the compressor 160, the desorbed emissions in Bed 1 are forced out of the bed and drawn towards the compressor 160. This may alternatively be understood as providing a vacuum effect on the inner volume of Bed 1, pulling desorbed emissions out of the bed. This pressure differential facilitates the removal of emissions from the bed during the regeneration stage. This effect, combined with the increased temperature of the adsorbent material (through contact with the corresponding heat exchanger), favours the desorption and further removal of the adsorbate from the bed. Once Bed 1 is sufficiently regenerated, or once a different bed becomes saturated with emissions, the beds transition again and Bed 1 is cooled for the adsorption phase. In other embodiments, this switching may occur after a preset residence time.

[0091] The compressor 160 is used to compress the desorbed emissions and direct them into a storage tank 162. The stored, compressed emissions can be utilised in further processes, which are not described herein.

[0092] The foregoing method describes the cyclical nature of the adsorption-based gas capture system 100. Each adsorption bed 110, 110’, as well as their corresponding heat exchanger pipes 120, 120’, adsorbent material 140, 140’ and reactor shells may have similar or identical arrangements to each other. The method described above may therefore be initialised with either of the inlets A or A in use. In otherembodiments, another inlet A” corresponding to a third adsorption bed may be the initial inlet. The cyclical nature of the system allows for any initialised configuration given that at least one arbitrary first bed is in the regeneration phase, in which hot DEG is received through the corresponding heat exchanger, and at least one second bed is adsorbing the cooled gas that has passed through the heat exchanger of the first bed.

[0093] Other beds in a system with more than two beds may operate in intermediary stages, such as heating or cooling. In a cooling stage of an arbitrary bed, the inlet valve IV may be closed, but the inlet A for receiving gas is closed also. In a heating stage, the inlet for receiving gas A and the feed valve FV may be open, but the desorbed valve DV of the bed may be closed.

[0094] The cycle operates such that in the foregoing method, the features Bed 1 and Bed 2, as well as their corresponding valves and inlets, may be swapped, equivalently embodying a cycle of the present invention.

[0095] Figure 3 illustrates a workflow describing the method according to the second aspect of the invention. The method may be executed by a gas capture system like that in Figure 1 , or another gas capture system, with multiple adsorption beds, configured to perform the following steps.

[0096] Firstly, the system receives, S302, exhaust gas into the heat exchanger of a first adsorption bed (e.g. see Figure 1, Bed 2). This may be through an inlet arranged to collect gas from a diesel engine. The gas typically arises from combustion reactions and will be hot when received into the adsorption bed.

[0097] The system then passes, S304, the collected exhaust gas through the heat exchanger of the first adsorption bed. This heat is harvested by the first adsorption bed, which is filled with captured emissions. This promotes desorption of adsorbed emissions from the bed. Simultaneously, the hot exhaust gas cools as it passes through the heat exchanger of the bed.

[0098] The system then passes, S306, the cooled exhaust gas to the internal volume of the second adsorption bed for adsorption.Figure 4 illustrates a workflow according to embodiments of the present invention. The workflow illustrates a method of cycling from receiving exhaust gas into one bed to receiving exhaust gas into another bed.

[0099] Specifically, when a first bed approaches adsorbate saturation, or a preset residence time has passed (J408), the receiving of exhaust gas is switched, S410, to the inlet of the second adsorption bed. This step may be performed by a control module. The control module may be connected to the inlets so as to selectively open and close them in response to the parameters in step J408.

[0100] Step S422 is the first step of the next cycle, as gas is received into the heat exchanger of the second adsorption bed, and thus the same cycle occurs for regenerating the second adsorption bed.

[0101] The system receives, S422, exhaust gas into the heat exchanger of the second adsorption bed. This may be through an inlet arranged to collect gas from a diesel engine. The inlet of the first adsorption bed may be closed.

[0102] The system then passes, S424, the collected exhaust gas through the heat exchanger of the second adsorption bed. The hot exhaust gas transfers heat energy to the adsorbent material in the bed, causing it to heat up.

[0103] The system then passes, S426, the cooled exhaust gas to the internal volume of the first adsorption bed for adsorption. Similarly, when it is detected that an arbitrary first bed approaches adsorbate saturation, ora preset residence time has passed (J428), the receiving of exhaust gas is switched, S430, to the inlet of the first adsorption bed.

[0104] After this step, the cycle repeats, ensuring continuous gas capture throughout the method. The inlets and corresponding valves (as illustrated in Figure 1) are selectively opened and closed in order to facilitate the switching between adsorption and regeneration phases in the beds.

[0105] Figure 5 illustrates a workflow according to embodiments of the present invention, in which Bed 2 undergoes desorption and Bed 1 undergoes adsorption.Exhaust gas is first received into the heat exchanger of Bed 2 (S502) and then moves to the condenser to be cooled and stripped of water (S503). Then, the gas is split into two streams (S504), where the flow is ready to pass through Bed 1. Stream 1 (S505) has the highest portion of the splitting process, and is illustrated as 90% of the exhaust gas, but this proportion is used merely as an example. Stream 1 passes through the adsorption arrays (S506), and the emissions are captured by the material inside Bed 1. This process increases the reactor temperature due to the exothermic nature of the adsorption process. Stream 2 (S505’) is the flow which passes through the outer shell of Bed 1 , none of which is captured, but is instead used to exchange heat (S506’) with the adsorption arrays that have gained heat through the adsorption process. Then, at the exit, Stream 1, which now contains no emissions, is combined with Stream 2 to be released to the ambient (S507).

[0106] Figure 6 illustrates a workflow according to embodiments of the present invention, which may be used with reference to Figure 1. The process begins with exhaust gas being received into the heat exchanger of Bed 1 (S1) where it initiates the adsorption cycle. Simultaneously, the adsorbed gas in Bed 1 becomes desorbed and is directed to a compressor and is compressed into a storage reservoir (S2). After the exhaust gas has passed through the heat exchanger of Bed 1 , it enters a condenser where it is cooled down (S3). Once cooled, the gas splits into two streams (S4), with 10% of the gas passing through the outer shell (“reactor shell”) of Bed 2 (S5), while the remaining 90% passes through the adsorption arrays within Bed 2 (S5’). The specific proportions into which the gas is split are not limited herein, with a 10 / 90% split used as an example. Inside Bed 2, the gas in the outer shell exchanges heat with the adsorption arrays, cooling them to improve adsorption efficiency (S6). As adsorption occurs, the temperature of the bed rises (S6’). The system continues to monitor the state of Bed 2, checking whether the saturation limit or residence time has been reached (R1). If the bed is not saturated, the adsorption process continues, clean gas is released to the ambient (S7), and the process returns to S1 to receive further exhaust gas. If the bed reaches its saturation limit or the residence time is reached, the system switches to receiving exhaust gas into Bed 2 (S8), beginning a new cycle for the bed.While Bed 2 is undergoing adsorption, Bed 1 is following a parallel process. Exhaust gas is received into the heat exchanger of Bed 2 (B1), and as the cycle progresses, the desorbed gas from Bed 2 is compressed into a storage reservoir (B2). The exhaust gas moves into a condenser where it is cooled down (B3), and then split into two streams (B4). Like Bed 2, 10% of the split gas passes through the outer shell of Bed 1 (B5), while 90% enters the adsorption arrays in Bed 1 (B5’). The gas exchanges heat with the adsorption arrays, cooling them to improve adsorption efficiency (B6), and as adsorption occurs, the temperature of the arrays rises (B6’). The system continuously checks if Bed 1 has reached its saturation limit (A1). If it has not yet reached the limit, the process continues, clean gas is released into the ambient (B7), and the system returns to B1 to receive further exhaust gas. If the bed reaches saturation, or the residence time has been reached, the system switches to receiving exhaust gas into Bed 1 (B8).

[0107] This process operates in a continuous cycle, alternating between adsorption and desorption phases for Bed 1 and Bed 2. When a bed reaches its saturation limit, it stops adsorption and switches to desorption, releasing the stored gas, which is then compressed into the storage reservoir (S2 for Bed 1 and B2 for Bed 2). Meanwhile, the other bed remains in the adsorption phase. At all times, when the beds are not saturated, clean gas is continuously released to the ambient, and the system cycles back to S1 (or B1 for the other stage in the cycle) to receive further exhaust gas, allowing for an efficient and continuous adsorption process.

[0108] One of the critical factors to consider is the residence time of gas mixtures as they pass through the solid adsorption bed. This parameter is affected by several variables, including the volume of material compacted within the bed, the bed’s diameter and length, and the mass flow rate of gas mixtures. Equally important are the pressure and temperature conditions within the reactor, as they play a pivotal role in the efficiency of the desorption and adsorption processes.

[0109] Figure 7 shows a piping and instrumentation diagram of a pretreatment stage 700, including a rectifier unit 710, H2O2 tank 730, alkali 740, coolant fluid and condensate reservoir 720. The pretreatment stage 700 may be comprised at the condenser 150 of Figure 1, such that hot exhaust gas passes through thepretreatment stage 700 after it is passed through the heat exchanger (HX) of an adsorption bed. In this way, the hot gas may be treated and cooled before it is passed to the adsorbent material of another adsorption bed.

[0110] Hot exhaust gas from the engine enters main unit and first passes through a primary heat exchanger. The recovered thermal energy is used in the regeneration (desorption) process of the corresponding adsorption bed, improving overall system efficiency while protecting downstream components from excessive thermal loads.

[0111] After primary heat recovery via the heat exchanger of one adsorption bed, the exhaust gas enters a quench or rectifier (pretreatment) unit 710. The quench or rectifier unit 710 performs multiple critical functions: further cooling of the exhaust gas; condensation of water vapour from the exhaust gas; removal of acid gases such as SO2and NO2; reduction in SOx levels to below 1 ppm; and reduction in NOx.

[0112] Additional cooling of the exhaust gas may be achieved via a coolant fluid circulation into and out of the rectifier unit 710. Condensed liquid containing acidic species is routed to a chemical treatment section of the rectifier unit 710. In the chemical treatment section of the rectifier unit 710, hydrogen peroxide (H2O2) is introduced from an H2O2tank 730 to oxidise NO to NO2, improving adsorption efficiency. Alkali dosing from an alkali source 740 into the condensate reservoir 720 neutralises the acidic solution, forming stable salts such as sodium sulphites and nitrates.

[0113] This integrated pretreatment stage 700 ensures that the exhaust gas is properly conditioned before entering the capture system while managing all liquid byproducts safely.

[0114] After moisture and acid removal, the cleaned exhaust gas is routed back to the main unit through a blower 750. The blower 750 provides the required pressure and flow control, overcomes system-induced backpressure, and protects engine performance.The conditioned gas is then introduced into the main unit, including a vessel (adsorption bed) with structured packing and adsorbent material. The gas is passed into the adsorbent material of another adsorption bed in the main unit (that is different to the adsorption bed through which the DEG passed via heat exchanger). In this way, one adsorption bed operates in “adsorption mode”, capturing treated gas at low temperature. A second adsorption bed undergoes thermal regeneration (desorption). An automated alternating valve system switches gas flow between reactors to ensure uninterrupted treatment and subsequent adsorption of the exhaust stream.

[0115] Figure 8a and 8b illustrate how the capture rate, for CO2 and N2O respectively, changes where the adsorption mass (M_a) and mass flow rate (m) are varied. Initially, all cases maintain a 100% capture rate, but as adsorption progresses, efficiency declines. Higher adsorbent mass (M_a=387 kg) sustains capture for a longer period, while lower mass (M_a=188 kg) leads to a faster decline. Additionally, reducing the mass flow rate (m) extends the residence time before capture degradation. The results emphasize that increasing adsorbent mass and optimising flow rate improve CO2capture duration. The trend shows that increasing the adsorbent mass and optimising the flow rate can prolong effective CO2capture. The same trend is observed for N2O in Fig 7b, but the decline rate is more severe for N2O than CO2.

[0116] The Fig 8c illustrates cyclic CO2and N2O capture over time (seconds) for one of the adsorption beds. The black solid line represents CO2capture (mol / gr) on the left y-axis, while the dashed line corresponds to N2O capture (mol / gr) on the right y-axis. Both gases exhibit a repeating triangular pattern, indicative of the periodic adsorption and desorption cycles. CO2capture is significantly higher than N2O capture, but both follow a similar trend, peaking before sharply decreasing to zero at the end of each cycle. By switching the flow of DEG between adsorption beds a steady rate of capture can be achieved. Overall, lower flow rates and higher adsorbent mass increase residence time, improving capture efficiency across all cases.In alternative implementations, the cooling process may be a phase in the adsorption-regeneration (or desorption) cycle. One example of this uses four or more adsorption beds, which operate in a sequential four-phase cycle: cooling, adsorption, heating, and regeneration. In the cooling phase, the cooled exhaust gas is passed to the reactor shell of the bed to facilitate cooling, and both the heat exchanger inlet and the adsorption bed outlet are closed. Once the bed drops below a preset adsorption temperature, the bed transitions to the adsorption phase. In adsorption, exhaust gas is passed to the cooled adsorbent material in the bed, and the bed begins to accumulate adsorbed emissions. Upon saturation (or a preset threshold parameter is met), the bed transitions to the heating phase. In heating, the heat exchanger of the bed begins receiving exhaust gas by switching to the corresponding inlet. The hot exhaust gas transfers heat energy to the bed. Once the temperature of the bed meets a preset threshold, or is above the desorption temperature of the material, the bed transitions to the regeneration phase. In regeneration, the outlet of the bed is open, and desorbed emissions are released from the bed. This can be facilitated by a pressure differential caused by a compressor; such that desorbed emissions are drawn out of the bed and into a storage tank. Once the bed is sufficiently regenerated, the cycle restarts and the bed is cooled again.

[0117] In some implementations, multiple adsorption beds may operate in the same phase simultaneously. In cases where the number of adsorption beds in the system is large, the beds may cycle through the adsorption and regeneration phases so as to facilitate the continuous capture of gases in at least some of the beds, while others are regenerated.

Claims

CLAIMS1. A system for capturing exhaust gases, the system comprising:a plurality of adsorption beds, each comprising an enclosed internal volume containing adsorbent material and a heat exchanger, the heat exchanger comprising a conduit arranged through the internal volume of the adsorption bed, such that heat energy is exchanged between a fluid transported through the conduit and the adsorbent material of the bed during use;a first inlet for receiving an exhaust gas into the heat exchanger of a first adsorption bed; anda connector arranged to connect the heat exchanger of a first adsorption bed to the internal volume of a second adsorption bed such that, in use, exhaust gas that has passed through the heat exchanger of the first adsorption bed is passed into the internal volume of a second adsorption bed for adsorption by the adsorbent material.

2. The system of claim 1 , wherein the second adsorption bed comprises an inlet for receiving exhaust gas and a connector arranged to connect the heat exchanger of the second bed to the internal volume of the first adsorption bed.

3. The system of claim 2, further comprising a controller arranged to switch the adsorption bed into which exhaust gas is received, thereby facilitating a sequential input of exhaust gas into the heat exchanger of each adsorption bed in the system.

4. The system of any of claims 1 to 3, further comprising a storage tank wherein each adsorption bed comprises an outlet valve arranged to selectively release desorbed emissions from the internal volume of the adsorption bed to the storage tank.

5. The system of claim 4, further comprising a controller configured to control the inlet valve and outlet valve of each adsorption bed such that, in use, exhaust gas is received into the heat exchanger of the adsorption bed through the inlet valve, thereby heating the adsorbent material to facilitate desorption ofadsorbed emissions, the desorbed emissions then released from the internal volume of the adsorption bed through the outlet valve into the storage tank.

6. The system of claim 4 or 5, further comprising a compressor arranged between the plurality of adsorption beds and the storage tank, the compressor configured to:receive desorbed emissions from the outlet valve of an adsorption bed; compress the desorbed emissions; anddirect the compressed emissions into the storage tank.

7. The apparatus of claim 6, wherein the compressor is configured to generate a pressure difference relative to the internal volume of a connected adsorption bed when the adsorption bed is undergoing desorption, thereby drawing out desorbed emissions in the adsorption bed, and facilitating desorption of adsorbed emissions from the adsorbent material therein.

8. The system of any preceding claim, wherein the conduit of each heat exchanger comprises at least one pipe provided through the adsorbent material of each adsorption bed.

9. The system of any preceding claim, further comprising a condenser, the condenser arranged within the connector between the heat exchanger of the first adsorption bed and internal volume of the second adsorption bed, and configured to:receive exhaust gas from the heat exchanger of the first adsorption bed; cool the exhaust gas; andremove water from the cooled exhaust gas.

10. The system of claim 9, further comprising a wastewater tank connected to the condenser for storing water removed by the condenser.

11. The system of any preceding claim, further comprising a reactor shell enclosing one or more of the adsorption beds, wherein the connector of a first adsorption bed is configured to connect the heat exchanger of the first adsorption bed to both the internal volume of a second adsorption bed within the reactor shelland an inlet of the reactor shell, such that the cooled exhaust gas is split into two or more streams, wherein at least one stream passes into the internal volume of the second adsorption bed, and at least one other stream passes into the reactor shell, thereby facilitating the cooling of the second adsorption bed.

12. The system of any preceding claim, wherein the adsorbent material of each adsorption bed comprises a zeolitic material and / or a solid containing negative salt cations for attracting polar molecules in an exhaust gas.

13. The system of any preceding claim, wherein the adsorbent material of each adsorption bed comprises a porous material with pore openings of 1-50A, preferably 10A.

14. The system of any preceding claim, wherein each adsorption bed further comprises a product valve configured to release non-adsorbed exhaust gases that are not adsorbed when passed through the internal volume of the adsorption bed.

15. A method of capturing exhaust gases using a plurality of adsorption beds, each adsorption bed comprising a heat exchanger and an enclosed internal volume containing an adsorbent material, the method comprising:receiving an exhaust gas by a first inlet into the heat exchanger of a first adsorption bed;passing the exhaust gas through the heat exchanger of the first adsorption bed; andpassing, by a connector, the cooled exhaust gas that has passed through the heat exchanger of the first adsorption bed to the internal volume of a second adsorption bed for adsorption.

16. The method of claim 15, the method further comprising:receiving the exhaust gas via a second inlet, wherein the second inlet is arranged to receive an exhaust gas into the heat exchanger of the second adsorption bed;passing the exhaust gas through the heat exchanger of the second adsorption bed; andpassing, by a connector, the cooled exhaust gas that has passed through the heat exchanger of the second adsorption bed to the internal volume of the first adsorption bed for adsorption.

17. The method of claim 16, the method further comprising:switching the receiving of exhaust gas into the first and second inlets, so as to sequentially receive exhaust gas into the heat exchanger of each adsorption bed.

18. The method of any of claims 15 to 17, wherein the step of passing the cooled exhaust gas to the second adsorption bed further comprises:dividing the stream of cooled exhaust gas into two or more streams; passing at least one stream to the internal volume of the second adsorption bed; andpassing at least one stream to a reactor shell, wherein the reactor shell encloses the second adsorption bed such that the stream of cooled gas facilitates the cooling of the second adsorption bed.

19. The method of any of claims 15 to 18, the method further comprising: after passing the exhaust gas through the heat exchanger of the first adsorption bed, passing the exhaust gas through a condenser; the condenser arranged between the heat exchanger of the first adsorption bed and internal volume of the second adsorption bed; and the method comprises:receiving cooled exhaust gas from the heat exchanger of the first adsorption bed; andremove water from the cooled exhaust gas.

20. The method of any of claims 15 to 19, the method further comprising: switching the releasing of desorbed emissions from the internal volume of each adsorption bed to a storage tank, through an outlet valve arranged on each of the adsorption beds.

21. The method of claim 20, the method further comprising:controlling the inlet valve and the outlet valve arranged on each of the adsorption beds such that exhaust gas is received into the heat exchanger of thesecond adsorption bed through the inlet valve of the second adsorption bed, thereby heating the adsorbent material contained within the inner volume to facilitate desorption of adsorbed emissions, the desorbed emissions then released from the internal volume of the second adsorption bed through the outlet valve and into a storage tank.

22. The method of any of claims 15 to 21, the method further comprising: generating, by a compressor, a pressure difference in the internal volume of the second adsorption bed, thereby facilitating desorption of adsorbed emissions from the adsorbent material therein and drawing out desorbed emissions;wherein the compressor is arranged between the plurality of adsorption beds and the storage tank, and is further configured to:receive desorbed emissions from the outlet valve of the second adsorption bed;compress the desorbed emissions; anddirect the compressed emissions in the storage tank.

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