Carbon Capture and LNG

Carbon (CO2) capture and hard water were discussed last week, and this has resulted in several new releases on the topics, as listed in the newsletter. The CO2 Capture Project, based in Illinois, has just issued a report entitled ‘A Technical Basis for Carbon Dioxide Storage’, explaining how to assess and manage industrial-scale CO2 geological storage (CGS) projects. Specifically in relation to ground water, a well chosen site for such CO2 storage is quoted as being at greater than 800m depth, with functional barriers that provide isolation from drinking water and the near-surface environment, as well as between geological storage intervals. More background can be found in the Enviro-talk pages on Processingtalk, (Link).
The CCP article reminds us that the Intergovernmental Panel on Climate Change believes CCS could contribute 15-55 per cent of the cumulative mitigation effort until 2100, while the International Energy Agency found that the cost of containing climate change would be 70 per cent higher without CCS.

So, I would like to raise a different aspect to this topic, to hopefully get some further feedback. I am a real fan of the LNG projects that are springing up around the world: but one article I consulted recently over CCS commented that most existing expertise in CO2 separation systems had been developed from the requirement to remove the CO2 and moisture from natural gas before it is liquefied, ie at the well. But instead of storing or re-injecting this CO2, it was quoted that the separated gas is “typically released back into the atmosphere”. Admittedly the levels of CO2 are lower than in combustion processes, between 5-10%, but we should not just throw captured CO2 back into the atmosphere. This would be an obvious place to look to avoid some CO2 emissions: does such CO2 release actually happen anywhere?

It certainly is not the case in Norway, as you would expect: the modern facilities of the Snohvit LNG project (led by Statoil) receives gas containing between 5% and 8% carbon dioxide from the offshore field: this is separated out at the processing and liquefaction facility and then returned via a separate 160km pipeline for storage/sequestration beneath the seabed (2,600m below the sea bed on the edge of the original gas reservoir source, in the 45m to 75m thick Tubasen sandstone formation) thus preventing undue (CO2) pollution and allowing Norway to adhere to the Kyoto treaty (Link).


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