Home     Directors        Concept        Mission       Plan        Technical       Contact        

Carbon dioxide extraction from the atmosphere

A number of methods to extract CO2 from the air exist using various absorbents, either amines or carbonate/bicarbonate solutions. The CO2 recovery from the absorber can be achieved by pressure swing, heating or electrolysis. 

This note outlines alternative method that proposes the use of

a gas separation system using sodium hydroxide spray towers to capture the CO2.

Another way is by using gas diffusion membranes.  Current oil industry practice is to use several types of membranes to remove carbon dioxide from natural gas in order to lower the carbon dioxide level to below 2% for regulatory purposes for insertion into transmission grids. Conventional membranes require large pressure differences, we have a novel concept that could be an alternative to a liquid absorber.

The aims of our phase one research project

1.  To demonstrate that sodium hydroxide can be used to recover pure carbon dioxide from the air.    The air is passed up through a large tower against a fine mist spray of strong sodium hydroxide solution. The sodium hydroxide reacts with the carbon dioxide to form sodium carbonate.   The sodium carbonate solution is then pumped to a special electrolytic cell where an applied current causes the trapped carbon dioxide to be released, and the sodium hydroxide is regenerated for recycling into the tower.Because there is only a tiny amount (0.6 grams) of carbon dioxide in each cubic metre of air, any process must make careful use of available energy. In order to use little energy or resources, the process should maintain the humidity of the ‘cleaned’ air.

2.  To demonstrate a membrane material that has the capability of extracting carbon dioxide from the atmosphere economically and in industrial amounts.

3.  To demonstrate the synthesis of fuel from hydrogen and carbon dioxide using the most efficient cascade of catalytic converters, using the lowest viable temperatures and pressures.

Plan

A year long programme is envisaged to undertake the following prototype construction.

A gas separation tower to be built to collect CO2 from the atmosphere with sodium hydroxide

An electrolytic CO2 stripper built to concentrate the CO2 and recycle the sodium hydroxide.

In parallel research will be done on alternative membrane separation of CO2 from air.

A laboratory fuel synthesis reactor will be commissioned, comprising a water gas shift reactor and a FT reactor to make a tangible quantity of fuel per day to demonstrate the complete route from air to commercial fuel.

These together with a hydrogen electrolysis unit will be integrated into a demonstrable pilot plant