Construction nearing completion The recent rainfall and flooding in Central Queensland slowed, but did not deter, efforts to ensure the Callide Oxyfuel Project will be fully commissioned and capturing carbon dioxide by the end of 2011.
Retrofitting oxyfuel technology to the Callide A Power Station and construction of new aspects of the project commenced in March 2010 after the completion of earthworks onsite. The retrofitting process has including building key plant on the ground and then lifting them into place on the side of the power station.
The largest and most complex lift was the placement of the Primary Air (Gas) Heater, weighing 65 tonnes, more than 35 metres up to the top of the power station. The Primary Air (Gas) Heater (pictured) is used in the oxyfuel combustion process to pre-heat flue gas that is recirculated to the coal pulverising mills, so that the coal is adequately dried in the milling process to achieve stable combustion in the boiler.
Another key lift undertaken on site late last year was the Flue Gas Low Pressure Heater.
The first stage of commissioning is expected to commence shortly with the firing of an oil torch in the boiler.
Commissioning of a complex project like the Callide Oxyfuel Project will take considerable time and effort. Project Director, Dr Chris Spero, said the commissioning phase has been broken into four key elements for Stage 1 of the Project.
"First, we will be re-commissioning the boiler under normal air firing conditions," Dr Spero said.
"This will be followed by commissioning of the oxygen plant and then the boiler under oxy-firing conditions.
"In parallel, construction of the carbon dioxide capture plant will continue though to about September and then this plant will be commissioned."
The fully integrated operation of the oxyfuel process (oxy-combustion and carbon dioxide capture) is expected to be completed by late 2011.
For more information on the Callide Oxyfuel Project, please visit the website www.callideoxyfuel.com
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Fast FactsThe oxyfuel technology can be bolted on (or retrofitted) to existing coal-fired power stations.
The target capture rate for carbon dioxide emissions using oxyfuel technology is 90%.
A portion of the exhaust gases from the process are recycled to control combustion conditions and to concentrate the amount of carbon dioxide in the exhaust gas stream, making the capture process more efficient.
The basic elements in the Callide Oxyfuel Project have all been tried and tested elsewhere. For example, oxyfiring has been used in different industries and the storage of carbon dioxide underground was pioneered by the oil and gas industry in the late 1970’s. What is unique about the Callide Oxyfuel Project is the way these technologies have been linked and the scale to which they will be applied.
Carbon storage is not a new concept. The oil and gas industries have been successfully capturing carbon for storage for almost 50 years.
The carbon dioxide captured after oxyfuel combustion will initially be transported by truck in liquid form, which is already a very common practice around the world - dry ice is solid or frozen carbon dioxide.
Carbon dioxide pumped underground will gradually settle in the storage formation held in place by non-porous cap rock. Monitoring wells will be installed to analyse the carbon dioxide in the reservoir.
The Callide Oxyfuel Project is one of only a handful of coal-fired low emissions projects in the world to move past concept to construction phase.
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