Patent ID: 12188444

DETAILED DESCRIPTION

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 toFIGS.1and2. The apparatus is denoted generally by reference numeral1. The apparatus1comprises a plurality of pockets, only eight of which2a-2hare shown inFIG.2and only four being shown inFIG.1. The hemi-cylindrical pockets2a-2hare circumferentially arranged around main body3, between two face-forming sheets (not shown). The main body3is essentially disk-shaped and is rotatably mounted on output rotor4. Main body3is located in a container5of an aqueous solution of monoethanolamine6, a carbon dioxide scavenger, the container5being located on the sea floor in shallow sea water. The apparatus1also comprises air pump7which is located on a small floating platform8. The pump7is powered by a small wind turbine/windmill9, and delivers air (containing carbon dioxide) through conduit10to gas inlet11located at the bottom of container5. Gas introduced through gas inlet11passes into pocket2hand the buoyancy of the gas exerts an upwards force on the pocket2h. This force is transferred to the rotatably-mounted main body3, and the main body3rotates. This rotation causes rotation of output rotor4, the rotation of which may be used to generate power. In the present example, output rotor4is provided with a gear13which is meshed with gear14which is coupled to dynamo15. Rotation of gear13causes rotation of gear14and rotation of drive shaft (not shown) of dynamo15. Therefore, the buoyancy of the carbon dioxide containing gas may be used to generator electricity. The gears13,14may be chosen to apply a resistance to rotation of main body3. It may be desirable to apply a resistance to rotation of main body3in 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.

The apparatus1comprises heater16which is configured to heat the solution of monoethanolamine located in container5, and which is powered by dynamo15. It may be desirable to heat the monoethanolamine solution6to 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 heater16may 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 %.

Each pocket2a-2his provided with a three-dimensional mesh120, formed from a plastic scourer. For the purpose of clarity only pocket2his shown containing the mesh. Without wishing to be bound by theory, it is thought that the mesh20increases the interaction between the inlet gas and the liquid which comprises the monoethanolamine, and/or the mesh20provides 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 mesh20breaks larger bubbles into smaller ones, thereby increasing the interaction between the gas and the surrounding liquid.

Referring toFIG.2, the apparatus is arranged so that bubbles rising from inlet11are received in the right hand side of pocket2h. As the main body3rotates and pocket2hrotates and rises, gas passes through mesh20and leaves pocket2hfrom 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 pocket2h, which facilitates increased reaction between the monoethanolamine and the carbon dioxide in the gas.

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 apparatus1comprises a regeneration region25which is in fluid communication with container5via conduit28. The regeneration region25is provided for the regeneration of the monoethanolamine from the carbamate. After a certain period of use, some of the contents of container5are transferred to regeneration region25. The regeneration region25is provided with a heater26to heat the contents of the regeneration region25. Heater26is powered by dynamo15. Heating of the carbamate to about 110-125° C. forms monoethanolamine and releases carbon dioxide which is collected in gas canister30. The monoethanolamine is then returned to container5via conduit29.

Gas leaving the pockets2a-2hcollects in the top portion of container5, and leaves the container5via gas outlet32which is provided with a one-way valve (not shown) which is configured to release gas from container5but inhibit ingress of water.

An exemplary method of the second, fourth and sixth aspects of the present invention will now be described with reference toFIG.3. The method is denoted generally by reference numeral200. The method200comprises passing201a gas into a liquid, and using202the buoyancy of the gas in the liquid to generate power. When the gas is passed into the liquid carbon dioxide in the gas is removed203by 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 removed203by reaction with the monoethanolamine. Furthermore, passage on the inlet gas into the pocket passes the gas into a three-dimensional mesh (not labelled inFIG.3) located in the pocket which increases210the 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 transferred204to a regeneration region in which the monoethanolamine is regenerated205by heating the carbamate. Gaseous carbon dioxide is collected207and monoethanolamine is transferred206back to the region in which monoethanolamine is reacted with the carbon dioxide.

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.

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.

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.

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

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.

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.

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.

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.

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.

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.