APPARATUS AND METHOD

Abstract

An apparatus (1) for generating power is provided. The apparatus comprises: at least one pocket (2a-h) for collecting inlet gas which rises through a liquid in which the at least one pocket may be located; an output rotor (4); and a greenhouse gas scavenger (6) for removing greenhouse gas from an inlet gas; the apparatus being configured so that collection of inlet gas causes movement of the pocket, the pocket being coupled to the output rotor so that movement of the pocket causes rotation of the output rotor. A method is also provided.

Claims

1. An apparatus for generating power comprising: at least one pocket for collecting inlet gas which rises through a liquid in which the at least one pocket may be located; an output rotor; and a greenhouse gas scavenger for removing greenhouse gas from the inlet gas; the apparatus being configured so that collection of inlet gas causes movement of the pocket, the pocket being coupled to the output rotor so that movement of the pocket causes rotation of the output rotor.

2. An apparatus according to claim 1 in which the greenhouse gas scavenger removes greenhouse gas by reacting with, or adsorbing or absorbing, said greenhouse gas.

3. An apparatus according to claim 1 wherein the greenhouse gas scavenger is a carbon dioxide scavenger and comprises a base (such as hydroxide), a CO.sub.2-binding mineral or an amine, and if the carbon dioxide scavenger comprises an amine, then optionally the amine is a primary or secondary amine, optionally selected from the group consisting of diethanolamine, monoethanolamine, methyldiethanolamine, diisopropanolamine and aminoethoxyethanol (diglycolamine).

4. An apparatus according to claim 1 wherein the greenhouse gas scavenger is provided as, or in, a liquid, and optionally the at least one pocket is located in said liquid.

5. An apparatus according to claim 1 comprising a heater for heating the greenhouse gas scavenger in a region in which the greenhouse gas scavenger is in contact with greenhouse gas, the heater optionally being powered by the output rotor.

6. An apparatus according to claim 1 wherein the at least one pocket is associated with a rotatable main body so that movement of said pocket causes rotation of the main body, the main body optionally being located in a liquid into which greenhouse gas-containing inlet gas is introduced.

7. (canceled)

8. An apparatus according to claim 1 comprising a gas breaker for breaking a stream of inlet gas into bubbles or for breaking bubbles of inlet gas into smaller bubbles, the gas breaker being located in the gas flow path upstream of the pocket.

9. (canceled)

10. An apparatus according to claim 1 comprising a mesh for passage of inlet gas into or therethrough, the mesh optionally being a three-dimensional mesh, optionally located in a pocket.

11. An apparatus according to claim 1 comprising one or more means for increasing the interaction between the inlet gas and the greenhouse gas scavenger, optionally comprising a stirrer, shaker, vibrator, reciprocator, a gas breaker or a mesh.

12. An apparatus according to claim 1 comprising a regeneration region for the regeneration of the greenhouse gas scavenger, the apparatus optionally comprising a heater for heating the greenhouse gas scavenger when in the regeneration region.

13. A method comprising passing an inlet gas comprising greenhouse gas into a liquid, using the buoyancy of the gas to generate power and removing greenhouse gas from said gas.

14. A method according to claim 13 wherein the greenhouse gas comprises one or more of carbon dioxide, methane, nitrous oxide, a chlorofluorocarbon (such as CFC-12), a hydrofluorocarbon (such as HFC-23), sulphur hexafluoride and nitrogen trifluoride, and optionally comprises one or both of carbon dioxide and methane.

15. A method according to claim 13 or claim 14 wherein the greenhouse gas is removed using a greenhouse gas scavenger, thereby forming a removal product.

16. A method according to claim 15 wherein removing greenhouse gas from said inlet gas comprises reacting the greenhouse gas with a greenhouse gas scavenger to form the removal product, or adsorbing or absorbing greenhouse gas with a greenhouse gas scavenger to form the removal product, and optionally treating the removal product to generate the greenhouse gas scavenger.

17. (canceled)

18. A method according to claim 13 comprising collecting said inlet gas in one or more pockets, wherein the one or more pockets are optionally located in the liquid, the liquid being, or comprising, a greenhouse gas scavenger, and optionally breaking-up bubbles upstream of the pocket.

19-21. (canceled)

22. An apparatus for removing greenhouse gas from a greenhouse gas-containing inlet gas, the apparatus comprising a container for the storage of a liquid, a gas inlet for the introduction of a greenhouse gas-containing inlet gas into the liquid, a greenhouse gas scavenger for removing greenhouse gas from the inlet gas and one or more means for increasing the interaction between the inlet gas and the greenhouse gas scavenger.

23-31. (canceled)

Description

DESCRIPTION OF THE DRAWINGS

[0100] Embodiments of the present invention will now be described by way of example only with reference to the accompanying schematic drawings of which:

[0101] FIG. 1 shows a schematic view of an apparatus according to a first embodiment of the invention;

[0102] FIG. 2 shows a schematic view of a portion of the apparatus of FIG. 1; and

[0103] FIG. 3 is a schematic representation of a method according to an embodiment of the invention.

DETAILED DESCRIPTION

[0104] An exemplary embodiment of an apparatus in accordance with both the first, third and fifth aspects of the present invention will now be described with reference to FIGS. 1 and 2. The apparatus is denoted generally by reference numeral 1. The apparatus 1 comprises a plurality of pockets, only eight of which 2a-2h are shown in FIG. 2 and only four being shown in FIG. 1. The hemi-cylindrical pockets 2a-2h are circumferentially arranged around main body 3, between two face-forming sheets (not shown). The main body 3 is essentially disk-shaped and is rotatably mounted on output rotor 4. Main body 3 is located in a container 5 of an aqueous solution of monoethanolamine 6, a carbon dioxide scavenger, the container 5 being located on the sea floor in shallow sea water. The apparatus 1 also comprises air pump 7 which is located on a small floating platform 8. The pump 7 is powered by a small wind turbine/windmill 9, and delivers air (containing carbon dioxide) through conduit 10 to gas inlet 11 located at the bottom of container 5. Gas introduced through gas inlet 11 passes into pocket 2h and the buoyancy of the gas exerts an upwards force on the pocket 2h. This force is transferred to the rotatably-mounted main body 3, and the main body 3 rotates. This rotation causes rotation of output rotor 4, the rotation of which may be used to generate power. In the present example, output rotor 4 is provided with a gear 13 which is meshed with gear 14 which is coupled to dynamo 15. Rotation of gear 13 causes rotation of gear 14 and rotation of drive shaft (not shown) of dynamo 15. Therefore, the buoyancy of the carbon dioxide containing gas may be used to generator electricity. The gears 13, 14 may be chosen to apply a resistance to rotation of main body 3. It may be desirable to apply a resistance to rotation of main body 3 in order to slow rotation speed, thereby retaining the carbon dioxide containing gas in contact with the solution of monoethanolamine for a longer period of time.

[0105] The apparatus 1 comprises heater 16 which is configured to heat the solution of monoethanolamine located in container 5, and which is powered by dynamo 15. It may be desirable to heat the monoethanolamine solution 6 to increase the reactivity of the monoethanolamine with the carbon dioxide, and thereby increase the amount of carbon dioxide which is removed from the gas. The heater 16 may be configured to heat the monoethanolamine to about 25-40° C., for example. The concentration of the monoethanolamine may be, for example, any suitable concentration, but may typically be from 3-50 wt %.

[0106] Each pocket 2a-2h is provided with a three-dimensional mesh 120, formed from a plastic scourer. For the purpose of clarity only pocket 2h is shown containing the mesh. Without wishing to be bound by theory, it is thought that the mesh 20 increases the interaction between the inlet gas and the liquid which comprises the monoethanolamine, and/or the mesh 20 provides a surface which may be releasably coated with monoethanolamine by the liquid. It is also thought (once again, without wishing to be bound by theory) that the mesh 20 breaks larger bubbles into smaller ones, thereby increasing the interaction between the gas and the surrounding liquid.

[0107] Referring to FIG. 2, the apparatus is arranged so that bubbles rising from inlet 11 are received in the right hand side of pocket 2h. As the main body 3 rotates and pocket 2h rotates and rises, gas passes through mesh 20 and leaves pocket 2h from the left hand lip (not shown). Without wishing to be bound by theory, it is believed that this arrangement slows the inlet gas down, increasing residence time in the pocket 2h, which facilitates increased reaction between the monoethanolamine and the carbon dioxide in the gas.

[0108] When the monoethanolamine reacts with carbon dioxide it forms a reaction product in the form of a carbamate. That carbamate group cannot react further with carbon dioxide and therefore it is desirable to regenerate the monoethanolamine from the carbamate. This is usually done by heating the carbamate to 110-125° C. In order to facilitate this, the apparatus 1 comprises a regeneration region 25 which is in fluid communication with container 5 via conduit 28. The regeneration region 25 is provided for the regeneration of the monoethanolamine from the carbamate. After a certain period of use, some of the contents of container 5 are transferred to regeneration region 25. The regeneration region 25 is provided with a heater 26 to heat the contents of the regeneration region 25. Heater 26 is powered by dynamo 15. Heating of the carbamate to about 110-125° C. forms monoethanolamine and releases carbon dioxide which is collected in gas canister 30. The monoethanolamine is then returned to container 5 via conduit 29.

[0109] Gas leaving the pockets 2a-2h collects in the top portion of container 5, and leaves the container 5 via gas outlet 32 which is provided with a one-way valve (not shown) which is configured to release gas from container 5 but inhibit ingress of water.

[0110] An exemplary method of the second, fourth and sixth aspects of the present invention will now be described with reference to FIG. 3. The method is denoted generally by reference numeral 200. The method 200 comprises passing 201 a gas into a liquid, and using 202 the buoyancy of the gas in the liquid to generate power. When the gas is passed into the liquid carbon dioxide in the gas is removed 203 by reaction with the monoethanolamine to form a carbamate. Furthermore, when the buoyancy of the gas is used to generate power, the gas is collected in pockets as described above. When the gas is in the pockets, it is in contact with the surrounding monoethanolamine solution, and therefore carbon dioxide in the gas is removed 203 by reaction with the monoethanolamine. Furthermore, passage on the inlet gas into the pocket passes the gas into a three-dimensional mesh (not labelled in FIG. 3) located in the pocket which increases 210 the interaction between the inlet gas and the monoethanolamine solution. As mentioned above, after a certain amount of time, liquid comprising the carbamate reaction product is transferred 204 to a regeneration region in which the monoethanolamine is regenerated 205 by heating the carbamate. Gaseous carbon dioxide is collected 207 and monoethanolamine is transferred 206 back to the region in which monoethanolamine is reacted with the carbon dioxide.

[0111] Whilst the present invention has been described and illustrated with reference to particular embodiments, it will be appreciated by those of ordinary skill in the art that the invention lends itself to many different variations not specifically illustrated herein. By way of example only, certain possible variations will now be described.

[0112] The example described above illustrates an apparatus and method which generate power. Those skilled in the art will realise that for the apparatus and method of the third, fourth, fifth and sixth aspects of the present invention, then there is no need for the apparatus and method to generate power because the apparatus and method of the third and fourth aspects of the present invention respectively are concerned with causing the increase of interaction between the inlet gas and the greenhouse gas scavenger.

[0113] The example above describes an apparatus with a rotatable main body. Those skilled in the art will realise that other configurations are possible for apparatus in accordance with the first aspect of the present invention. For example, a plurality of pockets may be attached to a belt with two rotors, for example, as shown in WO2008/082221.

[0114] Those skilled in the art will realise that other arrangements of pockets may be used. For example, the pockets may be hemi-spherical.

[0115] The example above illustrates how carbon dioxide may be removed from an inlet gas. Those skilled in the art will realise that the example may be suitably modified to facilitate removal of other greenhouse gases, such as nitrous oxide, a chlorofluorocarbon, a hydrofluorocarbon, sulphur hexafluoride, nitrogen trifluoride or methane. For example, hydroxyl radicals may be used to remove methane.

[0116] The example above describes the use of a three-dimensional mesh in the form of a plastic scourer. Those skilled in the art will realise that other meshes may be used. For example, a mesh may be formed from a ribbon, a string or the like which is folded, coiled or otherwise shaped to form a three-dimensional mesh structure.

[0117] The example above describes the use of monoethanolamine solution to remove carbon dioxide from a gas. Those skilled in the art will realise that other materials may be used to remove the carbon dioxide, such as other amines, a base (such as a hydroxide solution or suspension) or a suitable carbon-dioxide binding mineral.

[0118] The example above describes the use of wind power to power a pump to provide air to the pockets of the apparatus. Those skilled in the art will realise that any suitable power source may be used to power the pump, but may typically comprise a “green” or renewal source of power, such as waves, tidal or solar.

[0119] The example above describes the use of the apparatus and method of the present invention in littoral (i.e. coastal) waters. Those skilled in the art will realise that the apparatus and method of the present invention may be used essentially anywhere, and typically on land, in which case the floating platform described above would not be needed.

[0120] Where in the foregoing description, integers or elements are mentioned which have known, obvious or foreseeable equivalents, then such equivalents are herein incorporated as if individually set forth. Reference should be made to the claims for determining the true scope of the present invention, which should be construed so as to encompass any such equivalents. It will also be appreciated by the reader that integers or features of the invention that are described as preferable, advantageous, convenient or the like are optional and do not limit the scope of the independent claims. Moreover, it is to be understood that such optional integers or features, whilst of possible benefit in some embodiments of the invention, may not be desirable, and may therefore be absent, in other embodiments.