Carbon dioxide (CO2) compression is a necessary part of any carbon capture process, and Air Products has lauded the benefits of its oxyfuel technology towards potential carbon sequestration processes.

Air Products' oxyfuel technology has optimised the compression process to remove impurities, to an acceptable purity level in the gas that makes carbon sequestration possible.

That was the message delivered by Vince White, a Research Associate in the Energy Technology group at Air Products. White made the revelation to attendees in a presentation at the 9th International Conference on Greenhouse Gas Control Technologies (GHGT-9) in Washington, D.C.

The Conference, organised by MIT in collaboration with the IEA Greenhouse Gas R&D Programme, was sponsored largely by the US Department of Energy (DOE).

White indicated thats oxyfuel technology can reduce the cost of capturing CO2 for the power industry, and that Air Products has specifically focused on the purification of the resulting oxyfuel combustion flue gas - developing a robust process for the efficient removal of trace impurities.

The reduction of these impurities to an acceptable purity level is necessary, before any carbon captured could be transported for underground storage.

Removing impurities
Air Products' patented sour compression technology uses a staged compression process to optimise pressure, hold-up and residence time, to allow removal of impurities including sulfur dioxide, nitrous oxides, mercury, and other heavy metals from the CO2 containing gas during the compression process. This allows cost savings in the oxyfuel combustion process and also minimises the content of such components in the sequestered CO2.

The company's technology has been demonstrated in experimental work carried out by Imperial College London, with actual flue gas from Doosan Babcock's 160kW coal-fired rig in Renfrew, Scotland, as part of the Oxycoal-UK Project.

White presented the findings of this work to the conference audience and said, $quot;The experimental data collected by Imperial College demonstrates the theory of this technology which, combined with previous findings that nitrogen, argon and oxygen are easily removed, shows that oxyfuel CO2 capture technology can successfully remove multiple impurities.$quot;

$quot;This is essential to being able to deliver CO2 for sequestration that meets the acceptable purity level. The data shows that impurities removal can be achieved during compression and without more expensive and complex flue gas de-sulfurization units and de-NOx units. The ability to achieve this at lower costs is encouraging to industries with large scale CO2 emissions,$quot; he added.

Air Products also recently announced another CO2 capture study, in collaboration with the Alberta Energy Research Institute. The study, focused on advanced carbon dioxide capture technology for use with gasification, is entitled 'Advanced Hydrogen and CO2 Capture Technology for Sour Syngas' and is expected to be completed by October 2010.