World Cement - November 2018

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November 2018 96 \ World Cement
to look at this technology and one pilot plant is
operating in Taiwan.
Biological processes are of great interest to
cement manufacturers and practically all of the large
international cement producers have performed
some type of experimentation with either algae or
microbes. Pilot projects have been started on almost
all continents, with several pilots being directly tied
to operating cement plants and others utilising
simulated flue gases. Interest in these technologies has
dissipated of late, as most indicated negative energy
balances. That is, the energy required to convert the
CO2 into a useful product was more than the energy
used to create the CO2 in the first place. Higher-end
products, such as cosmetics and pharmaceuticals, still
hold interest and the Taiwan pilot plant is proceeding
in this direction. These projects often require a large
physical footprint.
Membranes may be the simplest technology to
apply. A membrane is used to separate an exhaust
gas stream from a CO2 rich stream. The membrane
is designed to allow only CO2 molecules through,
while keeping all other gases and solids out. The CO2
movement is driven by a combination of pressure
and vacuum. Although this technology holds
promise, it still faces several challenges, such as the
large amounts of surface area necessary and the
deterioration of the membrane material due to gas
contaminants. At least one membrane technology has
been tested in a cement plant in Norway.
Cryogenic separation of CO2 relies on the unique
property of CO2 of having a triple point, whereby a
small move in either temperature or pressure allows
the CO2 to pass between the gaseous, liquid, and
solid phases. Gases are cooled to a point where CO2
is extracted, either as a liquid or a solid. This process
does not require any other reagents, but does require
a large amount of energy to drive. Cryogenic capture
of CO2 has been piloted for short durations at two
cement plants in the US.
Amines and similar liquid sorbent technologies
are the most well-known and advanced globally.
These technologies could blur the lines between
solids processing plants producing cement and
chemical plants operating sophisticated chemical
processes. Solid sorbents, especially carbonate
looping technologies, seem more similar to the solids
handling typical in cement plants. Cryogenic processes
are fairly simple, but require a large amount of
energy. Biological processes hold a high potential for
the future, as they can actually create a value-added
product. The trick is to find a product with sufficient
volume to use a large amount of CO2. Any of these
technologies can be added to an existing operation,
as long as space allows.
Conclusion
The landscape for CO2 regulations is still evolving,
with some jurisdictions taking a strong lead, while
most of the others wait to see what happens. This
leads to uncertainty in investment decisions: do
cement producers continue to build cement plants
as they currently do? If not, what changes should be
made? Tail pipe solutions can always be added to
existing cement plants at a later date. However, these
technologies may end up being more costly than
designed-in applications, such as oxy-combustion,
oxy-calcination, and indirect calcination. Many
technologies have been trialled but there are no clear
leaders or global solutions.
Enabling oxy-calcination as potentially a small
incremental investment in new plant design and
construction appears to be a reasonable insurance
policy against an uncertain future.
References
1. CSI Roadmap:
php/publications.
2. CRH Sustainability Report:
sustainability/sustainability-publications
3. Ultratech Sustainability Report: https://www.
4. Taiheyo Sustainability Report: -
5. Cemex Sustainability Report:
sustainability/reports/global-reports
6. LafargeHolcim Sustainability Report: https://www.
7. Heidelberg Sustainability Report: https://www.
8. IEA-CSI Technology Roadmap: Low-carbon Transition
in the Cement Industry:
index.php/key-issues/climate-protection/technology-
roadmap
9. ECRA Oxy-Combustion Pilots: .
com/News/story/163335/ecra-to-test-oxyfuel-on-
industrial-scale-with-two-pilot-projects.html
10. LEILAC Indirect Calcination: -leilac.
eu/latest-news
Further reading
KLINE, J., KLINE, C., ‘Cement and CO 2: What is
Happening’, IEEE Transactions on Industry Applications,
Vol. 51, No. 2 (March – April 2015 ) DOI: 10.1109/
TIA.2014.2339396.
About the author
John Kline is the Principal at Kline Consulting LLC, a
consulting firm assisting sustainable building material
companies (start-ups to global producers) to improve their
operational and environmental performance. Kline has
over 40 Years in the mineral processing industry working in
research, sales, plant design, engineering, commissioning,
and operations. He retired from Lafarge in June 2012 after
21 years, with the last 18 years in various international,
executive positions. Kline Consulting currently specialises
in green building products, CO2 reduction technologies,
and mercury abatement.