IMPROVEMENTS IN OR RELATING TO CARBON CAPTURE

Abstract

In one proposed application provided by the present invention, and as shown in FIG. 2, CO.sub.2 is captured from a dirty flue gas in a fluid bed Turboscrubber to be recycled rapidly to a fluid bed Turbostripper where it is desorbed into a clean air stream for introduction to a horticultural glass-house for enhancement of fruit, vegetable or other crop growth. In a further application of the present invention as shown in FIG. 3, CO.sub.2 enriched saltwater is circulated through a tank (7), to feed Algae thereby allowing fast photosynthesis to occur in, for example, the production of bio fuels. Alternatively, if the Algae suspension is sufficiently robust, it can be pumped around a Turboscrubber (2) and the Algae tank (7) in order to keep it in constant contact with the CO.sub.2 enriched aqueous solution.

Claims

1. A process for absorption of carbon dioxide gas in fluidised bed scrubbers, which enhances capture without chemical reaction by a combination of high liquid to gas ratios, being at least 20 litres/m.sup.3 and simultaneous use of saline solutions with an Ionic Strength of 0.2 or greater.

2. A process according to claim 1, characterised in that the fluidised bed employs hollow or low density solid plastic, foam or resin manufactured elements of any form, shape or size to ensure good contact and high interfacial area between counter current gas and liquid phases to minimise gaseous flow pressure drop and to avoid flooding.

3. A process according to claim 1, characterised in that the concentration of the carbon dioxide in the gas phase is preferably in excess of 1% by volume.

4. A process according to claim 1, characterised in that the carbon dioxide, once captured, is quickly, i.e. within a few minutes, removed from the liquid phase after absorptive capture into solution by cycling the liquid to a fluidised bed or other stripping device to enable desorption to take place.

5. A process according to claim 1, characterised in that the preferred solvent is water or any other suitable liquids.

Description

[0019] There now follows a detailed description of the invention, which is to be read with reference to the accompanying drawings in which:

[0020] FIG. 1 illustrates a graph of carbon dioxide capture rate and fluid bed pressure drop against L/G;

[0021] FIG. 2 is illustrative of a flue gas cleaning plant; and,

[0022] FIG. 3 is illustrative of a carbon dioxide capture and algae tank for photosynthesis.

[0023] FIG. 1 shows the relationship between both CO2 removal efficiency & pressure loss through the fluid bed versus L/G ratio for a bed of selected hollow, generally acorn shaped but distended elements made in polypropylene known as TurboPak in a test tower of 200 mm diameter and with a superficial gas velocity of 0.9 m/s.

[0024] The CO.sub.2 was captured in to a semi saturated aqueous solution of Calcium Chloride of about 50% of its pure CaCl.sub.2(aq) solubility limit in water at 12 C., (i.e. at about 31.5 g of CaCl.sub.2(c) per 100 g of water or 2.84 mol/litre) being the average temperature of the tested saline solution through the scrubber tower, the saline solution having an Ionic Strength of about 8.5 mol/litre.

[0025] Other fluidised bed elements are able to generate higher interfacial areas and, hence, greater capture efficiencies and lower pressure drops.

[0026] One proposed application of the process is shown in FIG. 2, whereby the CO.sub.2 is captured from a dirty flue gas in a fluid bed scrubber (TurboScrubber) then cycled rapidly to a fluid bed stripper (TurboStripper) where it is desorbed in to a clean air stream for introduction to a horticultural glass-house to enhance fruit, vegetable or other crop growth.

[0027] Another proposed application of the novel process provided by the present invention is illustrated in FIG. 3, in which process, either CO.sub.2 enriched salt water is circulated through a tank 7 containing Algae to feed the Algae, to allow fast photosynthesis to occur in, for example, the production of bio-fuels, or the Algae suspension, if sufficiently robust, can be pumped around the Turboscrubber 2 and the Algae tank 7 to keep it in constant contact with the CO.sub.2 enriched aqueous solution.

[0028] The Turboscrubber is provided with: [0029] a) an inlet 1 for the introduction of flue gas; [0030] b) an outlet 6 for gas of reduced CO.sub.2 content; and, [0031] c) a outlet line 5 including a pump 3 for feeding the treated flue gas to the Algae tank 7.

[0032] The Algae tank 7 comprises an optional stirrer 9, a bleed valve 8 and on outlet line with a return pump 10 in a line 10a for recirculating treated flue gas to the Turboscrubber 2.

[0033] An optional Algae recycling line 4 is provided between the line 5 and the recirculating line 10a, see FIG. 3.

[0034] Modifications may be made to the above described development within the scope of the Claims appended hereto.