Environmental Engineering Reference
In-Depth Information
as tertiary amines, carbonates and amino acids) that are also less toxic, corrosive
and volatile than those used in similar non-biomimetic systems. For example, this
system does not result in the emission of the known carcinogen nitrosamine which
is the case in systems that use piperazine (a chemical promoter used to accelerate
CO
2
absorption) (Carley
2012
). Initial testing on an Alcoa aluminium smelter in
Deschambault, Quebec, indicated removal of 80 % of CO
2
that would otherwise
have been emitted into the atmosphere (Hamilton
2007
). The CO
2
emissions are
combined with waste bauxite residue, which is difficult to manage and potentially
dangerous, in order to neutralise it and create a product that has secondary uses and
revenue generating potential (Carley
2012
). A larger pilot project on a power plant
(for a company wishing to keep the project confidential) was conducted in 2011.
CO
2
Solutions reported positive but as yet unquantified and unpublished results.
Discussions of pilot projects in cement works and with major oil producers in
Alberta are underway to tailor the technology to these sectors (Carley
2012
). In
2014 the 'largest-ever scale test of a biocatalytic process for carbon capture' was
completed by CO
2
solutions in relation to its Alberta oil sands project. Results
showed an improvement of 33 % in energy consumption compared to the existing
carbon capture technologies for the capture of 90 % of the CO
2
emissions (CO
2
Solutions
2014
).
A similar example of biomimetic carbon sequestration technology can be found
in Stanford University research. Brent Constantz investigated how coral creates its
hard aragonite exoskeleton of calcium and magnesium carbonate and bicarbonate
minerals by using minerals, sea water and CO
2
. Based on his discovery of how
calcite and aragonite (polymorphs of calcium carbonate) are nucleated by the
marine organisms and subsequent replication of that in a laboratory, in 2007 he
formed the company Calera. Calera is developing technology that sequesters
carbon from industrial flue gas emissions, adds it to brine wastewater, sea water,
manufactured alkaline solutions, or brines extracted from geological deposits, and
from this process converts the gas first to carbonic acid and then to stable solid
minerals. These materials are used to produce high reactive cements that do not
require the calcining of the carbonate typically required to produce conventional
Portland cement. The resulting Calera cement process results in fewer CO
2
emissions than conventional cement production (Calera
2012
).
The technology has been applied at a demonstration level to California's Moss
Landing gas fired electricity power plant in the Monterey Bay area. Here sea water
is used, along with 92 % of the plant's 3.5 million tonnes of annual CO
2
emissions
and some of the waste heat and fly ash from the flue to create cement (Lovins and
Cohen
2011
, p. 285). Further independent analysis of the Calera process confirms
that up to 90 % of carbon emissions could be captured if the system was applied to
other suitable plants (Andersen et al.
2011
). The same report from the Institute for
Governance and Sustainable Development states: 'The advantage of the Calera
process relative to other proposed CCS (carbon capture and storage systems) is
that: it is available near-term at a lower estimated cost, it is [a] modular retrofit to
existing power plants making it scalable, and it has the potential to capture carbon
while producing a useful product'.
Search WWH ::
Custom Search