Posts Tagged ‘carbon capture’

Interview with Michele Aresta, Initiator of ICCDU and Member of the International Committee

This year’s ICCDU is the 17th edition of the event. What were your expectations when you started this series?
ICCDU was started after two Summer Schools funded by NATO on “CO2 as Carbon Source, 1986” and “Reaction Mechanisms in Enzymatic and Model carboxylation and reduction reactions based on CO2, 1989”.  The ICCDU Series was started for being the international forum where the scientific community working on CO2 conversion could meet. And this has been ICCDU since its start.

How would you describe the first ICCDU – was this more an academic discussion, or did you already envision concrete applications?
Surprisingly, in the 1980s there were already practical applications in the field of polymers from CO2 (Al-based catalysts) which went on stream. The scientific discussions already covered other themes such as CO2 reduction, photocatalysis, synthesis of fine chemicals, polymers such as polyurethanes and polycarbonates and so on. What people do today was well known in the 1980s. The interest in CO2 chemistry was at that time boosted by the“oil crisis” (1973, 2000s).  Climate change was not yet a serious issue. The low cost of oil has decreased the interest in CO2 conversion in the 2000-2010s. Now the push comes from climate change, a completely different motivation.
The scheme below was developed in 1987: it presents the vision I had about CCU 30 years ago:

 An Integrated approach to CO2 Utilization, M. Aresta, NATO ASI Series 1989.

The routes to go were very clear to me at that time! We are running now along those paths.

How has CCU (not the conference, but the technology) evolved since the first ICCDU? What expectations were met, what not? And did unexpected develpoments occur?
As I wrote in a paper published in JCOU in 2013 “The changing paradigm in CO2 conversion”, the availability of cheap PV-H2 makes possible today the exploitation of CO2 reduction to energy products, that did not make sense in a fossil-C based energy frame as it was in the 1980s. And this is a big step towards “circular economy of C”.

What is special about ICCDU compared to other events on the topic of CCS and CCU?
ICCDU is a scientific forum and gathers scientists from usually 35+ countries. In 2015 we had over 40 countries present. It is a global conference that has since a few years opened up to policy makers and industrialists: this is a must these days.

From your personal point of view, what are you looking forward to most at this year’s ICCDU?
In future years ICCDU will be more and more inclusive and will sustain the development of new science and technology in the direction of implementing a circular C-economy by integrating CO2 conversion, biotechnologies, and biomass utilization. Integration of biotechnologies, catalysis, photocatalysis is essential for CCU. Synthetic photochemistry is a key step. Integration with nature is essential. Learning from nature is our future.

What will, from your personal point of view, be the „next big thing“ in CCU?
Direct co-processing of water and CO2 for developing an “Economy based on CO2 and water”! This is the title of my most recent book published with Springer and this is my vision since ever.
CCU is cycling Carbon. CO2 is renewable carbon: one can cycle it again and again as Nature does. This is the basis of bioeceonomy: CCU is integrated with the Bioeconomy concept. We should not make the mistake of keeping biomass utilization and CCU apart! They must be integrated.

Join ICCDU 2019 in Aachen and discuss the opportunities and applications of carbon capture and utilization with experts from research and industry from all over the world!

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Hoffentlich CO2-frei

Event Report „Efficient Carbon Capture for Coal Power Plants“, 20th-22nd June, 2011, Frankfurt

Coal power plants will provide a significant share of Germany’s future energy generation. So-called CSS processes (carbon capture and storage) can help to reduce resulting CO2 emissions. CO2 is separated from the exhaust streams and subsequently stored or used for chemical reactions.

In order to separate the CO2 from the exhaust streams, additional energy is required, implying a substantial decrease in power plant efficiency. Currently power plants lose about 8-12 % of their efficiency degree due to CO2 separation. At a meeting in Frankfurt titled “Efficient Carbon Capture for Coal Power Plants”, June 20-22, 2011, new technologies were introduced that may help to reduce efficiency losses.

Post-Combustion Capture

In order to scrub the flue gasses and capture the CO2 post combustion, the exhaust streams are channeled through an amine solution that binds CO2. In the following step the CO2 is reseperated from the washing agent. This process requires about 2.8 GJ per t of CO2 recovered, equaling an efficiency loss of about 10 % in the power plant. With improved amine solutions or other washing agents, e.g. ionic liquids, the efficiency loss can be limited to about 2 GJ per ton CO2 (8 % efficiency loss).

 Oxyfuel process

In this process, coal is combusted with pure oxygen instead of air. The process thus yields almost pure CO2 that can then be liquefied and separated. Rectification of oxygen from air requires energy, leading to an efficiency loss of about 8 %. Newly developed oxygen-transporting membranes allow for a reduction of losses to about 6 %.

Pre-Combustion Capture

Similar to the Oxyfuel process, the coal is combusted with pure oxygen and subsequently processed at high temperatures in the presence of water vapor. The resulting synthesis gas is converted completely to CO2 and hydrogen and the CO2 is washed out. The remaining hydrogen is then burned to water. The decisive step for an increase in efficiency is the optimization of the shift reaction. The efficiency losses are estimated at about 7%. By using combined water gas–shift-membrane reactors efficiency can be improved by 0.5-1%.


In the Chemical Looping process, metal oxides or limestone (carbonate looping) is used in order to recover pure CO2. In comparison to the abovementioned processes, chemical looping is yet at an early development stage and its application in solid fuel processes is limited. With the assistance of appropriate oxygen carriers or stable calcium carbonate modifications, efficiency losses in power plants are expected to be restricted to about 4% (chemical looping) and 7% (carbonate looping) respectively.

A detailed description of all processes and an overview on the technological status of CO2 sequestration in coal power plants can be found in  Efficient Carbon Capture for Coal Power Plants, a book edited by the scientific organizers of the event, Prof. Detlef Stolten, Forschungszentrum Jülich, and Prof. Viktor Scherer, Universität Bochum. The contributions in this book are based on the presentations given at the event.

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