The European Union and led by SINTEF in Norway with ten other European partners has completed lab tests and is set to demonstrate a cost-effective CO2 capture technology.
Called the DemoCLOCK project, with a budget of €8.2 million, it is based on a special version of a technology called Chemical Looping Combustion (CLC).
This a wholly new take on CO2 capture. Rather than try to catch and remove the CO2 from the effluent stream at a combustion site, the idea is to separate out the oxygen from the atmosphere, feed it to the combustion, then collect the CO2 from the effluent without having to cope with the nitrogen and trace gasses during separation.
For the CO2 collection this has major advantages. The Europeans say the method produces an exit stream of only CO2 and water vapor. Capturing the CO2 from this stream is very easy because it only needs to be cooled down for the water to condense out, leaving a stream of pure CO2. That’s a very cheap path to CO2 production.
The matter then becomes separating out the oxygen at the front end.
The DemoCLOCK project uses a packed bed-based version of the chemical looping combustion concept. Simply said, a chemical is flooded with the oxygen in the atmosphere, cycled into a zone where the oxygen is released for the combustion and then returned to be reflooded for a complete cycle. The DemoCLOCK arrangement essentially creates the fuel reactor and the air reactor alternatively in a single reactor with all the CO2 capture advantages of a standard CLC process.
Another major advantage of the DemoCLOCK setup is that the oxygen carrier material wouldn’t have to be transferred between the two reactors. This greatly simplifies the process and is expected to speed up its commercialization.
The packed bed CLC concept was originally developed by a research group at Eindhoven University of Technology in the Netherlands that had formerly worked at the University of Twente in the Netherlands.
Cheap CO2 harvesting relies on never letting the nitrogen get into the combustion fire. CLC manages gas control by never allowing direct contact between the air and the fuel, so that the CO2 does not mix with nitrogen in the first place. Two reactors, an air reactor and a fuel reactor, are used in the CLC process, and an oxygen carrier in the form of metal oxide granules is circulated between them. In the air reactor, oxygen from the air is transferred to the oxygen carrier in a process called oxidation, producing lots of heat and a harmless stream of oxygen-poor air. The resulting oxygen-rich oxygen carrier is then transferred to the fuel reactor, where it provides the fuel with oxygen in the total absence of nitrogen.
The demonstration will work towards the proof of feasibility with a medium-scale demonstration of a 500kW packed bed CLC reactor in the Elcogas Company’s Integrated Gasification Combined Cycle (IGCC) power plant in Puertollano in Spain, the largest IGCC power plant in Europe.
The project aims to modify the current energy generation system to make it more sustainable and less dependent on imported fuels. This will help to address pressing challenges of security of supply and climate change, while increasing European industrial competitiveness.
Dr. Shahriar Amini of SINTEF, who is the Project Coordinator of DemoCLOCK said, “CLC itself is believed to be on the verge of becoming one of the most cost-effective ways of capturing CO2 from power plants. DemoCLOCK aims to demonstrate the technical, economic and environmental feasibility of implementing a packed bed-based chemical looping combustion (CLC) concept in large-scale power plants. This version of CLC is even less complex and more compact than the original CLC concept.”
A packed bed CLC may have other uses. Another use is convert gasified solid hydrocarbons such as syngas into hot streams of CO2 and oxygen-poor air where the heat can potentially be used for electricity generation. Packed bed reactor technology thus opens up the prospect of using various types of fuel like coal, wood, peat, coke, and other biomass.
There’s lots of testing to go. With good lab results and major firms signed on for the demonstration plan like Céramiques Techniques et Industrielles to make the materials and Foster Wheeler Italiana leading the commercialization step there is good reason to expect that combustion in a nitrogen free form may produce an abundance of CO2 for recycling in new ways.
We wish the Europeans great success. While some would like to sequester CO2, some would like to reuse it over and over again. But first we have to get it cheap. This technology just may be it.
By. Brian Westenhaus
Source: Will CO2 Capture Become Cheap