W.A.P. van den Bos, J. Jahn, L.J.P. van den Broeke, TNO, Delft,
For the further development of CCS (Carbon Capture and Storage) an integrated
approach is needed to optimize the full chain from capture, via transport to
application. It is to be expected that in the near future carbon dioxide
will be one of the largest commodities. Besides storage as the main option to
discard the captured CO2 more sustainable option are emerging where CO2 is used
as a feedstock.
A number of options for CO2 utilization are evaluated, and one of the most
promising options, biofixation of CO2 by microalgae, is discussed in detail.
One of the main aspects of mirco-algae is the scale-ability, both
and relatively large-scale applications can be envisaged. Results for the
growth of different microalgae in the presence of CO2 and the extraction of
valuable components from the algae biomass are presented.
In the near future, improving the efficiency of processes related to Carbon
Capture and Storage (CCS) will become increasingly important as currently the
implementation of post-combustion CO2 capture is not economically feasible. It
is anticipated that CO2 will become available from a multitude of different
sources, including power plants, refineries, gas processing plants and LNG
production, and various industries, like cement and steel. Furthermore, besides
these so-called point sources, another main source will be related to the
separation of CO2 from natural gas.
It is noted that a typical coal-fired power plant of 500 MW will produce in the
order of 4 to 5 Million tons of CO2 per year. Furthermore, the global annual
emission of CO2 in 2010 was about 30 Giga ton. Point sources like refineries,
power plants and various industries account for 30 to 40% to the global CO2
emissions, which boils down to about 10 Giga ton per year. Capture of the CO2
from these point sources is a logical starting point to evaluate option for
utilization of CO2.
Carbon capture and storage
In the coming decades large point source that produce CO2, like power plants
and refineries, will be retrofitted with so-called post- combustion CO2 capture
and newly constructed facilities will include a CO2 capture process. The main
CCS steps involve the removal of CO2 from flue gas using an absorption process.
The capture of the CO2 will be performed with an absorption process employing a
chemical absorption liquid. Most absorption process for post combustion use
alkanolamines, like mono-ethanol amine (MEA), as the absorption liquid.
Chemical absorption is the most feasible option because of the low partial
pressure of the CO2 in the flue gas. Typical values for the fraction of CO2 in
the flue gas from coal fired and natural gas fired power plant are in the range
of 10% to 15 % and 4% to 8 %,respectively.