DEVELOPMENTS IN CARBON CAPTURE
BY BO SVENSSON
Fortum and Sargas worked together in
a practical demonstration of the Sargas
capture technology at the Värtan coal-
fired plant shown here. The Värtan
plant is located in Stockholm, Sweden,
and is jointly owned by Fortum Oy and
the City of Stockholm.
Clean Power
Norwegian technology company strives to put the world on a “carbon diet”
Worldwide environmental concerns
have put focus on emissions of CO2
from burning fossil fuels. One way to
avoid harmful emissions is to reduce
the burning of such fuels, hereby
reducing the emission of the carbon
dioxide — another way is to capture
the emissions, making them harmless
by injecting them into the ground.
The difficulty has been, and is, to
capture the CO2 emitted from the
stacks, be it industrial facilities or
power plants. Major interest has been
focused on the coal-fired power plants,
since they are emitting higher amounts
of CO2 than most other industrial
plants, and certainly more than plants
running on liquid or gaseous fuels.
Norwegian company Sargas AS provides solutions for capture, storage,
transport and the commercial use of
CO2, including its ultimate disposition.
According to the company, they have
developed and verified the effectiveness
of its capture technology in a demonstration at the Värtan coal-fired power
plant located in Stockholm, Sweden.
Characteristics of the Sargas technolo-
gy include low costs, high availability,
robust CO2 chemical scrubbing, high
thermal efficiencies and ultra-low emis-
sions, said the company. Applying the
pressurized fluid bed combustion (PFBC)
process, the Värtan plant has been in
operation since 1989, with availability
above 90% in recent years.
Following 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 coal-fired
plant, located in Stockholm, Sweden,
jointly owned by Fortum Oy and the
City of Stockholm.
The demonstration plant was designed and built by Sargas engineers and
subcontractors, commissioned in third
quarter 2007. Testing was carried out
during fourth quarter 2007 and the first
quarter of 2008 using exhaust gas from
the coal-fired power plant. The test was
independently supervised by IFE.
During the test, the demonstration
plant was in operation with flue gas
running through it for 450 hours —
300 of those hours were with absorbent
in place. Results show that the actual
CO2 capture was 97 to 99%, depending
on operating conditions. In addition,
the absorbent loading and operating
point, i.e., ratio of reacted and unreact-ed carbonate, was as designed.
The results show that the capture
technology is not only feasible but has,
in fact, exceeded expectations.
“Our main objectives of the Värtan
test were to adequately demonstrate a
CO2 capture at a minimum of 95%
from an operational coal-fired power
plant, and to do this by treating a real
flue-gas stream from the pressurized
