Atmospheric steam desorption for direct air capture

1 . A method for separating gaseous carbon dioxide from a gas mixture, containing said gaseous carbon dioxide as well as further gases different from gaseous carbon dioxide by cyclic adsorption/desorption processes, comprising:

providing a sorbent material capable of adsorbing said gaseous carbon dioxide,

providing a container containing an adsorber structure with said sorbent material,

the adsorber structure being heatable to a temperature of at least 60° C. for the desorption of at least said gaseous carbon dioxide and

the container being openable to flow-through of the gas mixture and for contacting the gas mixture with the sorbent material for adsorption,

wherein the method comprises the following sequential and in this sequence repeating steps:

(a) contacting said gas mixture with the sorbent material to allow at least said gaseous carbon dioxide to adsorb on the sorbent material under ambient atmospheric pressure and ambient atmospheric temperature in an adsorption step, using a speed of an adsorption gas flow;

(b0) isolating said sorbent material with adsorbed carbon dioxide in said container from flow-through of the gas mixture while maintaining the temperature in the sorbent material;

(b1) injecting a stream of saturated steam essentially at ambient atmospheric pressure and thereby inducing an increase of the temperature of the sorbent material from ambient atmospheric temperature to a temperature between 60and 110° C. while pushing out air contained in the container while not yet directing an outflow of said container to product collection,

(b2-b3) extracting at least the desorbed gaseous carbon dioxide from the container and separating gaseous carbon dioxide from water, including by condensation, in or downstream of the container, while still injecting and/or circulating saturated steam at ambient atmospheric pressure into said container, thereby flushing and purging both steam and CO2 from the container;

(c) bringing the sorbent material to ambient atmospheric temperature;

wherein the speed of steam flow through the unit container in step (b 1 ) and/or on average in steps (b1)-(b3) is in the range of 0.5-10 times the speed of the adsorption gas flow in step (a),

wherein step (c) is carried out exclusively by contacting said gas mixture with the sorbent material under ambient atmospheric pressure and ambient atmospheric temperature to evaporate and carry away water in the container and to bring the sorbent material to ambient atmospheric temperature.

2 . The method according to claim 1 , wherein the speed of steam flow through the container in step (b1) and/or on average in steps (b1)-(b3) is in the range of 1-6 times, of the speed of the adsorption gas flow in step (a).

3 . The method according to claim 1 , wherein the speed of steam flow through the container in step (b1) and/or on average in steps (b1)-(b3) is in the range of 0.1-2m/s.

4 . The method according to claim 1 , wherein a ratio of a total cumulative fresh steam in steps (b1)-(b3) to the released extracted carbon dioxide is smaller than 40:1.

5 . The method according to claim 1 , wherein the duration of steps (b1)-(b3), or of steps (b0)-(b3), is less than 15 minutes.

6 . The method according to claim 1 , wherein a pressure within the container in at least one, or in all of steps (b0)-(b3) is in the range of less than +/−100 mbar (g), of the local ambient atmospheric pressure.

7 . The method according to claim 1 , wherein the flow of steam and desorbed gaseous carbon dioxide exiting the container in at least one of steps (b1)-(b3) is not directly fed to a steam or water/carbon dioxide separation device including a condenser, but is first passed through at least one further container containing a further adsorber structure with said sorbent material, the further adsorber structure being heatable to a temperature of at least 60° C. for the desorption of at least said gaseous carbon dioxide and the at least one further container being openable to flow-through of the gas mixture and for contacting the gas mixture with the sorbent material for an adsorption step.

8 . The method according to claim 1

using at least two containers, or at least 4 or at least 6 or at least 8 containers each containing a respective adsorber structure with sorbent material, each adsorber structure being heatable to a temperature of at least 60° C. for the desorption of at least said gaseous carbon dioxide and each container being openable to flow-through of the gas mixture and for contacting the gas mixture with the sorbent material for an adsorption step,

wherein the operation of the containers is synchronised in that there is at least one step for each container in one cycle of the set of containers, wherein a flow of steam and desorbed gaseous carbon dioxide exiting a first one of the containers in at least one of steps (b1)-(b3) is not directly fed to a steam or water/carbon dioxide separation device including a condenser but is first passed through at least one further container downstream of said first one of the containers.

9 . The method according to claim 1 , wherein the speed of steam flow through the container in step (b1) and/or on average in steps (b1)-(b3) is in the range of 2-4 times of the speed of the adsorption gas flow in step (a).

10 . The method according to claim 1 , wherein the speed of steam flow through the container in step (b1) or on average in steps (b1)-(b3) is in the range of 0.2-0.4 m/s.

11 . The method according to claim 1 , wherein the gas mixture in step (a) flows along a gas flow path having a cross-section, and the injected steam flows along a different gas flow path, and the cross-section of the gas flow path in step (a) is larger than the gas flow path of the steam in steps (b1)-(b3) through said container, namely 50 times larger than the gas flow path of the steam in steps (b1)-(b3) through said container.

12 . The method according to claim 1 , wherein the specific steam flow rate of a desorption process in steps (b1)-(b3) is constant, and in the range of 1-10 kg/h/kg sorbent material, or less than 5 kg/h/kg sorbent material.

13 . The method according to claim 1 , wherein a ratio of a total cumulative fresh steam in steps (b1)-(b3) to the released extracted carbon dioxide is smaller than 20:1.

14 . The method according to claim 1 , wherein the extraction of carbon dioxide is started when the carbon dioxide concentration at an outlet of a condenser, is above 30%,

or the extraction of carbon dioxide is stopped when the carbon dioxide flow at the outlet of the condenser, is below 0.6 or 0.5 l/min/kg sorbent material.

15 . The method according to claim 1 , wherein the pressure within the container in at least one, or in all of steps (b0)-(b3) is in the range of less than +/−50 mbar (g) of the local ambient atmospheric pressure.

16 . A device for carrying out the method according to claim 1 ,

said device comprising a steam source; and

at least one device for the separation of gaseous carbon dioxide from water,

wherein at a gas outlet side of said at least one device for separating carbon dioxide from water, there is one or both of a carbon dioxide concentration sensor and a gas flow sensor for controlling the desorption process.

17 . The device according to claim 16 ,

said device comprising a steam source;

the at least one container containing an adsorber structure with said sorbent material, the adsorber structure being heatable to a temperature of at least 60° C. for the desorption of at least said gaseous carbon dioxide and the container being openable to flow-through of the gas mixture and for contacting it-the gas mixture with the sorbent material for the adsorption step;

at least one condenser, for separating carbon dioxide from water,

wherein at a gas outlet side of said at least one condenser, there is at least one of, or both of a carbon dioxide concentration sensor and a gas flow sensor for controlling the desorption process.

18 . A method for separating gaseous carbon dioxide from a gas mixture, containing said gaseous carbon dioxide as well as further gases different from gaseous carbon dioxide by cyclic adsorption/desorption processes, comprising:

providing a sorbent material capable of adsorbing said gaseous carbon dioxide,

providing a container containing an adsorber structure with said sorbent material,

the adsorber structure being heatable to a temperature of at least 60° C. for the desorption of at least said gaseous carbon dioxide and

the container being openable to flow-through of the gas mixture and for contacting the gas mixture it with the sorbent material for adsorption,

wherein the method comprises the following sequential and in this sequence repeating steps:

(a) contacting said gas mixture with the sorbent material to allow at least said gaseous carbon dioxide to adsorb on the sorbent material under ambient atmospheric pressure and ambient atmospheric temperature in an adsorption step, using a speed of an adsorption gas flow;

(b0) isolating said sorbent material with adsorbed carbon dioxide in said container from flow-through of the gas mixture while maintaining the temperature in the sorbent material;

(b1) injecting a stream of saturated steam essentially at ambient atmospheric pressure and thereby inducing an increase of the temperature of the sorbent material from ambient atmospheric temperature to a temperature between 60 and 110° C. while pushing out air contained in the container while not yet directing an outflow of said container to product collection,

(b2-b3) extracting at least the desorbed gaseous carbon dioxide from the container and separating gaseous carbon dioxide from water, including by condensation, in or downstream of the container, while still injecting and/or circulating saturated steam at ambient atmospheric pressure into said container, thereby flushing and purging both steam and CO 2 from the container;

(c) bringing the sorbent material to ambient atmospheric temperature;

wherein the speed of steam flow through the container in step (b1) and/or on average in steps (b1)-(b3) is in the range of 0.5-10 times the speed of the adsorption gas flow in step (a),

wherein the gas flow mixture in step (a) flows along a gas flow path having a cross-section, and the injected steam flows along a different gas flow path in steps (b1)-(b3), and the cross-section of the gas flow path of the gas mixture in step (a) is larger than the gas flow path of the steam through said container by a factor of 1.5;

or wherein the gas flow mixture in step (a) flows along a gas flow path having a cross-section, and the injected steam flows along a different gas flow path in steps (b1)-(b3) through said container.

19 . The method according to claim 18 , wherein the gas flow path of the gas mixture in step (a) is on average along a first direction, and the gas flow path of the steam in steps (b1)-(b3) is on average along a second direction.

20 . The method according to claim 19 , wherein the first and second directions are essentially orthogonal.

21 . A method for separating gaseous carbon dioxide from a gas mixture, containing said gaseous carbon dioxide as well as further gases different from gaseous carbon dioxide by cyclic adsorption/desorption processes, comprising:

providing a sorbent material capable of adsorbing said gaseous carbon dioxide,

providing a container containing an adsorber structure with said sorbent material,

the adsorber structure being heatable to a temperature of at least 60° C. for the desorption of at least said gaseous carbon dioxide and

the container being openable to flow-through of the gas mixture and for contacting the gas mixture with the sorbent material for adsorption,

wherein the method comprises the following sequential and in this sequence repeating steps:

(a) contacting said gas mixture with the sorbent material to allow at least said gaseous carbon dioxide to adsorb on the sorbent material under ambient atmospheric pressure and ambient atmospheric temperature in an adsorption step, using a speed of an adsorption gas flow;

(b0) isolating said sorbent material with adsorbed carbon dioxide in said container from flow-through of the gas mixture while maintaining the temperature in the sorbent material;

(b1) injecting a stream of saturated steam essentially at ambient atmospheric pressure and thereby inducing an increase of the temperature of the sorbent material from ambient atmospheric temperature to a temperature between 60 and 110° C. while pushing out air contained in the container while not yet directing an outflow of said container to product collection,

(b2-b3) extracting at least the desorbed gaseous carbon dioxide from the container and separating gaseous carbon dioxide from water, including by condensation, in or downstream of the container, while still injecting and/or circulating saturated steam at ambient atmospheric pressure into said container, thereby flushing and purging both steam and CO2 from the container;

(c) bringing the sorbent material to ambient atmospheric temperature;

wherein the speed of steam flow through the container in step (b1) and/or on average in steps (b1)-(b3) is in the range of 0.5-10 times the speed of the adsorption gas flow in step (a),

wherein the specific steam flow rate of the desorption process in steps (b1)-(b3) is constant.

22 . A method for separating gaseous carbon dioxide from a gas mixture, containing said gaseous carbon dioxide as well as further gases different from gaseous carbon dioxide by cyclic adsorption/desorption processes, comprising:

providing a sorbent material capable of adsorbing said gaseous carbon dioxide,

providing a container containing an adsorber structure with said sorbent material,

the adsorber structure being heatable to a temperature of at least 60° C. for the desorption of at least said gaseous carbon dioxide and

the container being openable to flow-through of the gas mixture and for contacting the gas mixture it with the sorbent material for adsorption,

wherein the method comprises the following sequential and in this sequence repeating steps:

(a) contacting said gas mixture with the sorbent material to allow at least said gaseous carbon dioxide to adsorb on the sorbent material under ambient atmospheric pressure and ambient atmospheric temperature in an adsorption step, using a speed of an adsorption gas flow;

(b0) isolating said sorbent material with adsorbed carbon dioxide in said container from flow-through of the gas mixture while maintaining the temperature in the sorbent material;

(b1) injecting a stream of saturated steam essentially at ambient atmospheric pressure and thereby inducing an increase of the temperature of the sorbent material from ambient atmospheric temperature to a temperature between 60 and 110° C. while pushing out air contained in the container while not yet directing an outflow of said container to product collection,

(b2-b3) extracting at least the desorbed gaseous carbon dioxide from the container and separating gaseous carbon dioxide from water, including by condensation, in or downstream of the container, while still injecting and/or circulating saturated steam at ambient atmospheric pressure into said container, thereby flushing and purging both steam and CO2 from the container;

(c) bringing the sorbent material to ambient atmospheric temperature;

wherein the speed of steam flow through the container in step (b1) and/or on average in steps (b1)-(b3) is in the range of 0.5-10 times the speed of the adsorption gas flow in step (a),

wherein the extraction of carbon dioxide is started when the carbon dioxide concentration at an outlet of a separation device is above 20%

or the extraction of carbon dioxide is stopped when the carbon dioxide flow at the outlet of the separation device is below 1.2 or 0.7 l/min/kg sorbent material.

23 . A method for separating gaseous carbon dioxide from a gas mixture, containing said gaseous carbon dioxide as well as further gases different from gaseous carbon dioxide by cyclic adsorption/desorption processes, comprising:

providing a sorbent material capable of adsorbing said gaseous carbon dioxide,

providing a container containing an adsorber structure with said sorbent material,

the adsorber structure being heatable to a temperature of at least 60° C. for the desorption of at least said gaseous carbon dioxide and

the container being openable to flow-through of the gas mixture and for contacting the gas mixture with the sorbent material for adsorption,

wherein the method comprises the following sequential and in this sequence repeating steps:

(a) contacting said gas mixture with the sorbent material to allow at least said gaseous carbon dioxide to adsorb on the sorbent material under ambient atmospheric pressure and ambient atmospheric temperature in an adsorption step, using a speed of an adsorption gas flow;

(b0) isolating said sorbent material with adsorbed carbon dioxide in said container from flow-through of the gas mixture while maintaining the temperature in the sorbent material;

(b1) injecting a stream of saturated steam essentially at ambient atmospheric pressure and thereby inducing an increase of the temperature of the sorbent material from ambient atmospheric temperature to a temperature between 60 and 110° C. while pushing out air contained in the container while not yet directing an outflow of said container to product collection,

(b2-b3) extracting at least the desorbed gaseous carbon dioxide from the container and separating gaseous carbon dioxide from water, including by condensation, in or downstream of the container, while still injecting and/or circulating saturated steam at ambient atmospheric pressure into said container, thereby flushing and purging both steam and CO2 from the container;

(c) bringing the sorbent material to ambient atmospheric temperature;

wherein the speed of steam flow through the container in step (b1) and/or on average in steps (b1)-(b3) is in the range of 0.5-10 times the speed of the adsorption gas flow in step (a),

wherein the duration of steps (b1)-(b3), or of steps (b0)-(b3), is less than 6 minutes.

24 . A method for separating gaseous carbon dioxide from a gas mixture, containing said gaseous carbon dioxide as well as further gases different from gaseous carbon dioxide by cyclic adsorption/desorption processes, comprising:

providing a sorbent material capable of adsorbing said gaseous carbon dioxide,

providing a container containing an adsorber structure with said sorbent material,

the adsorber structure being heatable to a temperature of at least 60° C. for the desorption of at least said gaseous carbon dioxide and

the container being openable to flow-through of the gas mixture and for contacting the gas mixture with the sorbent material for adsorption,

wherein the method comprises the following sequential and in this sequence repeating steps:

(a) contacting said gas mixture with the sorbent material to allow at least said gaseous carbon dioxide to adsorb on the sorbent material under ambient atmospheric pressure and ambient atmospheric temperature in an adsorption step, using a speed of an adsorption gas flow;

(b0) isolating said sorbent material with adsorbed carbon dioxide in said container from flow-through of the gas mixture while maintaining the temperature in the sorbent material;

(b1) injecting a stream of saturated steam essentially at ambient atmospheric pressure and thereby inducing an increase of the temperature of the sorbent material from ambient atmospheric temperature to a temperature between 60 and 110° C. while pushing out air contained in the container while not yet directing an outflow of said container to product collection,

(b2-b3) extracting at least the desorbed gaseous carbon dioxide from the container and separating gaseous carbon dioxide from water, including by condensation, in or downstream of the container, while still injecting and/or circulating saturated steam at ambient atmospheric pressure into said container, thereby flushing and purging both steam and CO2 from the container;

(c) bringing the sorbent material to ambient atmospheric temperature;

wherein the speed of steam flow through the container in step (b1) and/or on average in steps (b1)-(b3) is in the range of 0.5-10 times the speed of the adsorption gas flow in step (a)

using at least at least 8 containers each containing an adsorber structure with said sorbent material, the adsorber structure being heatable to a temperature of at least 60° C. for the desorption of at least said gaseous carbon dioxide and the containers being openable to flow-through of the gas mixture and for contacting it-the gas mixture with the sorbent material for an adsorption step,

wherein the operation of the containers is synchronised in that there is at least one step for each container in one cycle of a set of containers, wherein the flow of steam and desorbate exiting a first one of the containers in at least one of steps (b1)-(b3) is not directly fed to a steam or water/carbon dioxide separation device including a condenser but is first passing at least one further container downstream of said first one of the containers.