CO2 - Greenhouse Gases - Climate Change

Greenhouse Gases, CO2 & CCS - Carbon Capture Streams ... see / CCS / Veolia / CSLF / MIT '97/ IFP /(Wikipedia) .....

CO2 is a key issue for GHG - Green House Gas - and climate change, which has attracted a lot of media comment (SMH, New Scientist, McKinsey Global Institute, Wall St Journal ). It has been considered internationally by the IPCC - Intergovernmental Panel on Climate Change for approximately 20 years. It has been reported that CO2 levels have increased by around 35% over the last two hundred years, with the rate increasing after 1950. Various strategies are being investigated around the world to either reduce or capture and sequester CO2 to offset global warming concerns. In 2008 the Australian issued a Green Paper on a Carbon Pollution Reduction Scheme. Note - also US Carbon Sequestration Reports & Research Papers Index

"Sustainable development is development that meets the needs of the present without compromizing the ability of future generations to meet their own needs." - Brundtland Commission's 1987 report : "Our Common Future".)

According to PEI (Power Engineering International Journal), CCS is not going to come cheaply - being an estimated 500-600 million Euros to retrofit a carbon capture unit to a 500MW power station. These comments were made by Dr. John Topper, managing director of the IEA's Clean Coal Centre, at the inaugural COAL-GEN Europe (from the organisers of POWER-GEN Europe, PennWell) held in Warsaw, Poland on 1-3 July. He considered it a key issue that in the short to medium term, that the point when carbon prices make CCS economic may be 10-15 years away. See Science Daily Environment Headlines for details on Australia's first carbon capture from power station flue gases at Loy Yang power station & reports of protests at the Port Waratah Coal Terminal in Carrington, Newcastle - stopping coal trains.

CO2 reduction methods proposed have included oxyfuel combustion in power stations. Implementing carbon capture could have significant infrastructure ramifications, eg modifications to existing oil platform topsides, power plants and other industrial installations. Options for storage or sequestration have included deep ocean storage, which has in turn raised concerns about increasing ocean acidfication as CO2 is converted to carbonic acid (H2CO3) when it dissolves in the oceans. Carnegie Institute at Stanford, California, suggests that in over 100 years the ocean's pH could drop from 8.2 to about 7.7 (Nace Materials Performance April 2006). Hence land based storage is likely to be considered in many cases, dependent upon favourable geological characteristics, and will potentially involve long distance transportation.

EPRI CO2 Management Discussion Paper 2007 & Intute CO2 resources - Alstom CCS

NACE conference papers in 2008 & 2009 cover supercritical CO2 corrosion issues - Choi & Nesic - Corrosion Behavior of Carbon Steel in Supercritical CO2 Ц Water Environments - indications are that supercritical co2 will not necessarily be corrosive - however the temperatures may be above the carbon steel creep range.(Note Supercritical CO2 also seems to be considered as the next generation of cleaning chemical instead of organic solvents)

Sequestration projects in Australia include Otway, Victoria and Chevron's Gorgon project at Barrow Island off Western Australia. Report%20Ministerial%20Council%2009-22-2005%20COAG.pdf

In Australia, transporting pressurised CO2, aka CCS, by pipelines, is likely to be considered to be one of the most feasible approaches, eg API 5LX-65 steel has been used in the USA. An example of a transportation projects was the previously proposed 220 km long Stanwell to Springsure CO2 pipeline in Queensland originally due for completion by 2011, but now canned. The risk assessment process established by the pipeline industry in Australian Standard AS2885 involves identifying all possible threats to the pipeline, metre by metre along its entire length, as is currently the case for natural gas pipelines. Materials related performance issues for CO2 transportation pipelines (metallurgical aspects - corrosion/fracture) have been highlighted in a UK University of Newcastle -Newcastle_2_07.ppt#268,1,Slide 1". In 2007 Det Norske Veritas proposed a number of projects for standards to be developed to address CO2 capture, transport and storage. Specifically, CO2/CCS streams have been highlighted as having safety/environmental issues, which differ from transporting natural gas and would have to be addressed, ie :

Бб when carbon dioxide mixes with water

it becomes acidic and corrosive aka "sweet gas corrosion"; thus unless dry when carbon manganese steels may be feasible, otherwise if wet then requiring corrosion resisting alloys or coated carbon manganese steels; of course drying of CO2 itself requires energy .. thus potentially generating further greenhouse gases
as well as forming crystalline hydrates which can plug/foul equipment & flowlines

Бб carbon dioxide is heavier than air, odourless and not flammable - with its hydraulic behaviour being very temperature sensitive and affected by the presence of impurities such CH4, H2S, C2, N2 and H2O - maximum limits would be anticipated for H2S and H2O - and recompression stations could be required along the length of a pipeline;

CO2 & Atmospheric Corrosion

At the 2007 European Coatings Conference held in Berlin, the view was expressed that

"Climate changes due to global warming and the greenhouse effect are likely to produce even more corrosive conditions in the future, because higher temperatures accelerate corrosion, and greater concentrations of carbon dioxide will increase carbonation rates and the acidity of rainfall. Therefore, there is an urgent need for innovative materials, better methods of investigation, and improved repair techniques in order to face known troubles as well as problems not yet identified. "

Another really interesting project with CO2 ramifications - Power from "Hot Rocks" aka "Hot Fractured Rocks"

- in some cases the "hot rocks" will be dry and water pumped in, in other cases there will already be a brine present

- sometimes high chlorides, hydrogen sulphide and carbon dioxide may be present in a pH of <6 - raising concerns about corrosion challenges

- in fact some information suggests that salt could be generated as a by product of hot rock projects