An air handling system, a method for controlling an air handling system and a computer program

Abstract

The disclosure relates to an air handling system (2000) for providing treated process air to an air consumer, the system (2000) comprising: a carbon dioxide catcher (200) comprising at least one reactor (210a-b) with a carbon capture material, a rotor (210) comprising a desiccant material, and a process air circuit (S1) configured to conduct process air through the rotor (210) and the carbon dioxide catcher (200) downstream of the rotor (210), wherein the carbon dioxide catcher (200) comprises a bypass air circuit (S2) connected to the process air circuit (S1) upstream and downstream of the at least one reactor (210a-b), wherein the system (2000) comprises a valve (220) configured to enable process air to be conducted through the bypass air circuit (S2), and a control unit (230) configured to control the valve (220) to conduct process air via the bypass air circuit (S2) based on a bypass criterion being met. The disclosure further relates to a method (300) for controlling an air handling system and a computer program.

Description

[0001] An air handling system, a method for controlling an air handling system and a computer program

[0002] Technical field

[0003] The present disclosure relates to an air handling system, a method for controlling an air handling system and a computer program. More specifically, the disclosure relates to an air handling system, a method for controlling an air handling system and a computer program as defined in the introductory parts of the independent claims.

[0004] Background art

[0005] Carbon dioxide (CO2) is a major greenhouse gas contributing to global warming and climate change and various ways of capturing the gas have been developed over the years. By capturing the carbon dioxide for example from industrial sources helps reducing the amount of this gas released to into the atmosphere, mitigating its impact on the environment. Different types of carbon capture material are known, for example covalent organic frameworks, metal-organic frameworks, activated carbon, zeolites and carbon nanotubes. Carbon capture materials are often also good at adsorbing water vapor, which can deteriorate the capturing of carbon dioxide. Air handling systems comprising carbon dioxide catchers therefore often comprise dehumidifiers upstream of the carbon dioxide catcher, such that the carbon capture material can capture the carbon dioxide more efficiently.

[0006] It is thus an advantage to have an integrated system with both a dehumidifier arrangement and a carbon dioxide catcher arrangement. However, if the airflow is abruptly and significantly reduced downstream of the dehumidifier, there will be significant disturbances in the dehumidifier arrangement which will severely affect the dewpoint control and energy efficiency to maintain stable operating conditions. Therefore, if the carbon dioxide catcher is abruptly shut down, the dehumidifier arrangement is today also shut down. This may have a negative effect on the air consumer expecting to receive the treated air from the system and other safety measures might be required to ensure safety of the air consumer.

[0007] There is thus a need for an improved air handling system comprising both a dehumidifier and a carbon dioxide catcher. An object of the present disclosure is to mitigate, alleviate or eliminate one or more of the above-identified deficiencies and disadvantages in the prior art and solve at least the above-mentioned problem.

[0008] Another object of the present disclosure is to achieve an air handling system which is more reliable, energy efficient and improves safety.

[0009] Hence, according to a first aspect there is provided an air handling system for providing treated process air to an air consumer, the air handling system comprising: a carbon dioxide catcher comprising at least one reactor with a carbon capture material, a rotor comprising a desiccant material, and a process air circuit configured to conduct process air through the rotor and the carbon dioxide catcher downstream of the rotor, wherein the carbon dioxide catcher comprises a bypass air circuit connected to the process air circuit upstream and downstream of the at least one reactor, wherein the air handling system further comprises at least one valve configured to enable process air to be conducted through the bypass air circuit and a control unit configured to control the at least one valve to conduct process air via the bypass air circuit based on a bypass criterion being met, wherein the bypass criterion comprises at least one of: that a temperature of the process air downstream of the at least one reactor is equal to or exceeds a predetermined output temperature threshold value, that a temperature of a safety thermostat is equal to or exceeds a safety temperature threshold value; and that one or more heater breakers of the carbon dioxide catcher has / have tripped.

[0010] The at least one valve may be arranged in the bypass air circuit. The at least one valve in the bypass air circuit is typically controlled to an open state to allow the process air to be conducted through the bypass air circuit. The process air circuit may comprise at least one valve configured to be controlled to enable the process air to be conducted through the bypass air circuit. A valve in the process air circuit may be controlled to a closed state to allow the process air to flow through the bypass air circuit. Typically, the carbon dioxide catcher comprises a plurality of valves, configured to be controlled by the control unit to control the flow of process air through the carbon dioxide catcher.

[0011] The rotor comprising a desiccant material may be referred to as a desiccant rotor. Such rotor comprises a sorption media, also called rotor media, which consists of corrugated panels forming axially extending channels through the rotor media. The rotor rotates slowly between a process airstream and a regeneration airstream and the rotor comprises a process section and a regeneration section. The process air flows through the channels of the rotor media and the rotor media either adsorbs or absorbs moisture. When the rotor rotates, the rotor media is heated by the hot regeneration air, and the rotor media releases its moisture into the regeneration air. Following regeneration, the rotor rotates back into the process airstream, where the process repeats itself. The rotor is thus configured to dehumidify the process air upstream of the carbon dioxide catcher.

[0012] The bypass criterion may relate to the carbon dioxide catcher. The bypass criterion may be a criterion that indicates that safety is endangered and that the process air should bypass the at least one reactor of the carbon dioxide catcher. Thus, when something has happened that affects the carbon dioxide catcher, the control unit may control the at least one valve to conduct the process air via the bypass air circuit instead of through the at least one reactor of the carbon dioxide catcher. By having a bypass air circuit, the process air from the dehumidifier can bypass the at least one reactor of the carbon dioxide catcher and be provided to the air consumer. Thus, even if the carbon dioxide catcher is malfunctioning and is being shut down, dehumidified air will always be provided to the air consumer. Today when something has happened related to the carbon dioxide catcher that might endanger the safety, the carbon dioxide catcher is shut down and so is the dehumidifier. However, this drastically reduces the reliability and operation of the system. The air consumer will no longer receive air which might cause problems, such as overheating and other safety measures might be required to ensure safety of the air consumer. Thus, to ensure safety, the air handling system according to the present disclosure goes into bypass mode allowing for dehumidified process air to be delivered to the air consumer also when the carbon dioxide catcher is not used. Continuation of the airflow towards the air consumer is this way ensured. Furthermore, the process air being conducted through the bypass air circuit can be used as cooling air and can this way be used to cool the at least one reactor when the at least one reactor has been abruptly shut down. Allowing the dehumidified process air to bypass the at least one reactor of the carbon dioxide catcher instead of closing down the whole system also saves energy since the uptime of the system is increased.

[0013] The carbon dioxide catcher may comprise a heat exchanger arranged to transfer heat between incoming and outgoing regeneration air. In some examples, the carbon dioxide catcher comprises a fan configured to adjust the flow of the regeneration air. The carbon dioxide catcher may also comprise an electric heater downstream of the heat exchanger, the electric heater further increasing the temperature of the regeneration air upstream of the at least one reactor. In some examples, the bypass criterion comprises that a temperature of the process air downstream of the at least one reactor is equal to or exceeds a predetermined output temperature threshold value. The temperature of the process air downstream of the at least one reactor will indicate if everything is working as it should in the system. When the temperature of the process air downstream of the at least one reactor becomes too high, it is indicating that something is wrong. Too high temperatures, above the predetermined output temperature threshold value, may be caused by the heat exchanger and / or electric heater malfunctioning and thus indicates that the carbon dioxide catcher is not functioning properly. In this event, the carbon dioxide catcher may be shut down and the process air from the dehumidifier should bypass the at least one reactor and be directly provided to the air consumer. Thus, when the temperature of the process air downstream of the at least one reactor becomes too high, it is best for safety reasons to bypass the process air.

[0014] The bypass criterion may comprise that the carbon dioxide catcher is being shut down. The carbon dioxide catcher may be shut down for various reasons, typically for safety. The carbon dioxide catcher may also be shut down for inspection or service and maintenance. As previously described, it is crucial that the air consumer expecting treated air from the air handling system receives air even when the carbon dioxide catcher is being shut down.

[0015] The bypass criterion may comprise that a temperature of a safety thermostat is equal to or exceeds a safety temperature threshold value. The carbon dioxide catcher may comprise at least one safety thermostat for monitoring and controlling the temperature within the carbon dioxide catcher to ensure safe and efficient operation. The at least one safety thermostat may be arranged upstream of the at least one reactor or downstream of the electric heater. The at least one safety thermostat will help preventing the carbon dioxide catcher from overheating, which can lead to inefficient carbon dioxide capture, degradation of the carbon capture material and potential damage to the equipment. The safety thermostat will also provide a safety mechanism to shut down or adjust the carbon dioxide catcher if temperatures exceed the predetermined safety temperature threshold value. The at least one safety thermostat may have tripped as a result of the temperature exceeding the safety temperature threshold value. The bypass criterion may thus be that at least one safety thermostat has tripped.

[0016] The bypass criterion may additionally or alternatively comprise that one or more heater breakers of the carbon dioxide catcher has / have tripped. The carbon dioxide catcher may comprise at least one electric heater and at least one heater breaker configured to protect the electric heater and the whole system from electrical overloads or faults. The heater breaker automatically cuts off the electrical supply to the electric heater if the current exceeds a safe level, preventing overheating and potential damage to the electric heater and other components. The heater breaker may also be configured to detect electrical faults such as short circuits, which could otherwise cause fires or equipment failure. Typically, if one or more heater breakers has / have tripped, it is an indicator that something is wrong and the carbon dioxide catcher is stopped. Thus, according to the present disclosure, when one or more heater breakers of the carbon dioxide catcher has / have tripped, the process air should be conducted via the bypass air circuit.

[0017] In one example, the bypass criterion comprises that a mode selector switch of the carbon dioxide catcher has been set to indicate an operational mode of the carbon dioxide catcher in which the process air is to be conducted via the bypass air circuit. The air handling system may comprise a mode selector switch, such as a physical or virtual button, lever or similar, which an operator can manoeuvre and thereby activate the bypass mode. In the bypass mode, the process air is conducted via the bypass air circuit.

[0018] The bypass criterion may alternatively comprise that the dewpoint of the process air from the rotor is too high. In such event, the process air should be bypassed the at least one reactor until a desired dewpoint has been reached. Moisture in the process air may cause the performance of the carbon capture material to suffer. For instance, carbon capture materials comprising zeolite, the zeolite will act as a dehumidifier before it acts as a carbon dioxide capture material. Thus, bypassing the at least one reactor if the moisture content of the process air is too high eliminates the problem of the carbon capture material being saturated by the moisture of the process air.

[0019] The air handling system may further comprise a first regeneration air circuit configured to conduct regeneration air through a regeneration sector of the rotor. The regeneration air for the first regeneration air circuit originates from outside the air handling system. The air handling system may also comprise a second regeneration air circuit configured to conduct regeneration air through the carbon dioxide catcher. The regeneration air for the second regeneration air circuit may originate from the bypass air circuit. This may specifically be the case during start-up of the carbon dioxide catcher.

[0020] The carbon dioxide catcher may comprise at least two reactors arranged in parallel. Each reactor comprises at least one reactor cassette comprising the carbon capture material. The process air is conducted through the carbon capture material and the carbon dioxide is adsorbed on the carbon capture material. The carbon capture material may comprise zeolites. The reactor may also be referred to as an adsorbent and / or absorbent unit. Thus, the reactor is a unit configured to adsorb and / or absorb carbon dioxide in process air conducted through the reactor.

[0021] According to a second aspect there is provided a method for controlling an air handling system according to the first aspect, the method comprising: conducting process air through the rotor; and conducting process air via the bypass air circuit based on the bypass criterion being met. The bypass criterion is described with regard to the first aspect of the present disclosure. The step of conducting process air via the bypass air circuit may comprise controlling the at least one valve to enable process air to flow through the bypass air circuit.

[0022] According to a third aspect there is provided a computer program comprising computer instructions which, when executed by a processor of the control unit of the air handling system according to the first aspect, causes the air handling system to carry out the method according to the second aspect.

[0023] Effects and features of the second and third aspects are to a large extent analogous to those described above in connection with the first aspect. Embodiments mentioned in relation to the first aspect are largely compatible with the second and third aspects.

[0024] The present disclosure will become apparent from the detailed description given below. The detailed description and specific examples disclose preferred embodiments of the disclosure by way of illustration only. Those skilled in the art understand from guidance in the detailed description that changes and modifications may be made within the scope of the disclosure.

[0025] Hence, it is to be understood that the herein disclosed disclosure is not limited to the particular component parts of the device described or steps of the methods described since such device and method may vary. It is also to be understood that the terminology used herein is for purpose of describing particular embodiments only, and is not intended to be limiting. It should be noted that, as used in the specification and the appended claim, the articles "a", "an", "the", and "said" are intended to mean that there are one or more of the elements unless the context explicitly dictates otherwise. Thus, for example, reference to "a unit" or "the unit" may include several devices, and the like. Furthermore, the words "comprising", "including", "containing" and similar wordings does not exclude other elements or steps. Brief of the

[0026] The above objects, as well as additional objects, features and advantages of the present disclosure, will be more fully appreciated by reference to the following illustrative and non-limiting detailed description of example embodiments of the present disclosure, when taken in conjunction with the accompanying drawings.

[0027] Figures la-b schematically show an air handling system according to examples of the present disclosure.

[0028] Figure 2 shows a diagram of a method for controlling an air handling system according to an example of the present disclosure.

[0029] Detailed description

[0030] The present disclosure will now be described with reference to the accompanying drawings, in which preferred example embodiments of the disclosure are shown. The disclosure may, however, be embodied in other forms and should not be construed as limited to the herein disclosed embodiments. The disclosed embodiments are provided to fully convey the scope of the disclosure to the skilled person.

[0031] Figures la-b schematically show an air handling system 2000 according to examples of the present disclosure. The air handling system 2000 is configured to provide treated process air to an air consumer. The air consumer is typically an industrial application, such as a manufacturing site or similar.

[0032] The air handling system 2000 comprises a carbon dioxide catcher 200 comprising at least one reactor 210a-b with a carbon capture material. More specifically, the at least one reactor 2101-b comprises at least one reactor cassette (not shown) comprising the carbon capture material. The air handling system 2000 also comprises a desiccant rotor 210 configured to dehumidify the process air upstream of the carbon dioxide catcher 200. Furthermore, the air handling system 2000 comprises a process air circuit SI configured to conduct the process air through a process sector zl of the rotor 210 and subsequently the carbon dioxide catcher 200 downstream of the rotor 210. The carbon dioxide catcher 200 comprises a bypass air circuit S2 connected to the process air circuit SI upstream and downstream of the at least one reactor 210a-b. The bypass air circuit S2 will thus conduct the process air around the at least one reactor 210a-b. The air handling system 2000 further comprises at least one valve 220 configured to enable process air to be conducted through the bypass air circuit S2, and a control unit 230 configured to control the valve 220 to conduct process air via the bypass air circuit S2 based on a bypass criterion being met.

[0033] The air handling system 2000 may also comprise an electric heater 240 and a heater breaker 242 arranged in vicinity of the electric heater 240. Furthermore, the air handling system 2000 may comprise at least one safety thermostat 244. In some examples, the air handling system 2000 also comprises a mode selector switch. By manoeuvring this switch, the operator can activate and inactivate the bypass mode in which the process air is conducted via the bypass air circuit S2.

[0034] The bypass criterion may comprise that a temperature of the process air downstream of the at least one reactor 210a-b is equal to or exceeds a predetermined output temperature threshold value. The bypass criterion may comprise that the carbon dioxide catcher 200 is being shut down. The bypass criterion may comprise that a temperature of a safety thermostat 244 is equal to or exceeds a safety temperature threshold value. The bypass criterion may comprise that one or more heater breakers 242 of the carbon dioxide catcher 200 has / have tripped. The bypass criterion may comprise that a mode selector switch of the carbon dioxide catcher 200 has been set to indicate an operational mode of the carbon dioxide catcher 200 in which the process air is to be conducted via the bypass air circuit S2.

[0035] The figure also shows a first regeneration air circuit S2 configured to conduct regeneration air through a regeneration sector z2 of the rotor 210. In this example, the carbon dioxide catcher 200 comprises at least two reactors 210a-b arranged in parallel.

[0036] Figure lb shows an air handling system 2000 configured similarly to the air handling system 2000 as disclosed in Figure la. Figure lb, however, shows a plurality of valves 222a-e that are not shown in Figure la. Two valves, 222a-b, are arranged upstream of the reactor(s) 210a, 210b and are configured to control the airflow into the reactors 210a, 210b. These valves 222a-b are thus configured to be closed when the process air is conducted via the bypass air circuit S2. Three valves, 222c; 222d; 222e are arranged downstream of the reactor(s) 210a, 210b and are configured to prevent that process air conducted via the bypass air circuit S2 is flowing back into the reactors 210a; 210b. It is to be understood that the carbon dioxide catcher 200 can comprise any number of valves for controlling the flow of process air and regeneration air through the carbon dioxide catcher 200. The control unit 230 is configured to control all valves 220; 222a-e in the carbon dioxide catcher 200.

[0037] Figure 2 shows a diagram of a method for controlling an air handling system 2000 according to an example of the present disclosure. The air handling system 2000 is configured as disclosed in Figure la or lb. The method comprises the steps of conducting S100 process air through the rotor 210; and conducting S200 process air via the bypass air circuit S2 based on a bypass criterion being met. The step of conducting S200 process air via the bypass air circuit S2 may comprise controlling the at least one valve 220 to enable process air to flow through the bypass air circuit S2.

[0038] The person skilled in the art realizes that the present disclosure is not limited to the preferred embodiments described above. The person skilled in the art further realizes that modifications and variations are possible within the scope of the appended claims. Additionally, variations to the disclosed embodiments can be understood and effected by the skilled person in practicing the claimed disclosure, from a study of the drawings, the disclosure, and the appended claims.

Claims

CLAIMS1. An air handling system (2000) for providing treated process air to an air consumer, the air handling system (2000) comprising:- a carbon dioxide catcher (200) comprising at least one reactor (210a-b) with a carbon capture material,- a rotor (210) comprising a desiccant material, and- a process air circuit (SI) configured to conduct process air through the rotor (210) and the carbon dioxide catcher (200) downstream of the rotor (210), wherein the carbon dioxide catcher (200) comprises a bypass air circuit (S2) connected to the process air circuit (SI) upstream and downstream of the at least one reactor (210a-b), wherein the air handling system (2000) further comprises:- at least one valve (220) configured to enable process air to be conducted through the bypass air circuit (S2), and- a control unit (230) configured to control the at least one valve (220) to conduct process air via the bypass air circuit (S2) based on a bypass criterion being met, wherein the bypass criterion comprises at least one of:• that a temperature of the process air downstream of the at least one reactor (210a-b) is equal to or exceeds a predetermined output temperature threshold value;• that a temperature of a safety thermostat (244) is equal to or exceeds a safety temperature threshold value; and• that one or more heater breakers (242) of the carbon dioxide catcher (200) has / have tripped.

2. The air handling system (2000) according to claim 1, wherein the bypass criterion comprises that the carbon dioxide catcher (200) is being shut down.

3. The air handling system (2000) according to claim 1 or 2, wherein the bypass criterion comprises that a mode selector switch of the carbon dioxide catcher (200) has been set to indicate an operational mode of the carbon dioxide catcher (200) in which the process air is to be conducted via the bypass air circuit (S2).

4. The air handling system (2000) according to any one of the preceding claims, further comprising:- a first regeneration air circuit (S2) configured to conduct regeneration air through a regeneration sector (z2) of the rotor (210).

5. The air handling system (2000) according to any one of the preceding claims, wherein the carbon dioxide catcher (200) comprises at least two reactors (210a-b) arranged in parallel.

6. A method (300) for controlling an air handling system (2000) according to any one of the preceding claims, the method comprising:- conducting (S100) process air through the rotor (210); and- conducting (S200) process air via the bypass air circuit (S2) based on the bypass criterion being met.

7. A computer program comprising computer instructions which, when executed by a processor (232) of the control unit (230) of the air handling system (2000) according to any one of claims 1-5, causes the air handling system to carry out the method (300) according to claim 6.

Images