Results
- CO2 - 98% captured
- NOX - below 5 PPM
- SOX - near non existent
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At Värtan in Stockholm, a coal fired power plant, applying the Pressurised Fluid Bed Combustion (PFBC) process has been in operation since 1989, with availability above 90% in recent years. The plant is owned jointly by Fortum OY of Finland and the City of Stockholm.
The pressurised flue gas from Värtan results from a fully fired process that contains very little oxygen and a high partial pressure of CO2. It is therefore possible to utilise well proven carbonate processes for CO2 scrubbing. By reconfiguring and integrating existing technology Sargas has created a power plant concept with more than 95% CO2 capture and NOX levels below 5ppm – the Sargas Ultra Low Emission Power (ULEP) plant.
The down scaled demo unit is based on a standard capture plant , which is in everyday use throughout the world’s chemical and process industries at unit sizes required for a full scale power plant. As a result, the technical risk of scaling up is limited.
Throughout 2005 and 2006 Siemens Power and ALSTOM carried out a verification study of the Sargas’ concept including full lab testing of the CO2 capture module. The results confirmed the feasibility of the power and capture processes.
During the same period, Sargas began talks with Fortum OY, Finland on the importance of ultra low emission power. Following a due diligence and benchmarking by Fortum of the Sargas technology, the two companies agreed during 2007 to work together in a practical demonstration of the Sargas capture technology, at the Värtan plant. The demonstration plant was designed and built by Sargas´ engineers and subcontractors, commissioned in 3rd quarter 2007.
Testing was carried out during 4th quarter 2007 and the 1st quarter of 2008 using exhaust gas from the Värtan coal fired power plant, supervised by the Norwegian Institute for Energy Technology (IFE) as independent observers. The results show that the capture technology is not only feasible but has in fact exceeded expectations. The main objectives of the Värtan demonstration were:
Demonstrate adequate CO2 capture at a minimum of 95% from an operational coal fired power plant; by treatment of a real flue-gas stream from a pressurised boiler.
Demonstrate adequate cleaning of the flue-gas to avoid settlement of particles in the flue-gas stream and damage to the gas-turbine.
Gather process experience and data to support final detailed design and scale-up of the Sargas flue-gas cleaning and CO2-capture for a coal fired Sargas power plant process.
All major goals were achieved:
The Sargas concept can guarantee 95 % CO2 capture efficiency.
The multi-step gas cleaning concept, gas filters, scrubbing, condensing is flexible, efficient and removes virtually all dust particles > 0.1 µm
Under full power conditions the concept proved to be intrinsically simple to operate and robust in its performance.
Absorbent quality remains very good and is expected to improve further.
Flue gas borne reactants are efficiently removed to extremely low levels (below detection limits in most cases) in the Sargas process.
The clean gas is “turbine-ready” and is much cleaner than actual flue gas
The concentration of NH3 AND HCI were reduced to below detection limits after the filter train whereas the SO2 concentration is below the detection limit at all process points.
The success of this demonstration effort would not have been achieved without the support of the following; Prof. Mats Westermark - The Royal Institute of Technology in Stockholm, The Norwegian Institute for Energy Technology, Siemens Power AG, Professor Gregory McRae of the Massachusetts Institute of Technology (MIT), Reaction Systems Engineering, Innovation Norway, Gassnova, Fortum, Eramet Norway, Tinfos and Sør-Norge Aluminium (jointly owned by Rio Tinto Alcan and Hydro Aluminium).
Verified by:
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