Efficient CO₂ capture from refined waste fuel using CLC technology (“CLC-SRF”)

Background and project purpose?
CO₂ emissions from conversion of waste-derived fuels are estimated to about 18 million tonnes per year (ERFO – European Recovered Fuel Organisation, 2015). The report further estimates the market to increase, to CO₂ emissions equivalent to more than 60 million tonnes per year. It is evident that capture of this CO₂ should be considered. Since about half of this waste is biogenic, it will also contribute to negative CO₂ emissions (“climate-positive” solution). Waste-derived fuels are well suited for conversion to heat in fluidised bed furnaces. This has been done commercially for many years. The purpose of the project is to take this further to fluidised bed Chemical Looping Combustion (CLC) furnaces. Using waste-derived fuels in CLC has not been demonstrated earlier and represents a new solution for CO₂ capture with potentially high capture rate and low efficiency loss.

What was the project objective?
The main objective of the project was to evaluate the feasibility and potential benefits of converting solid waste-derived fuels in a Chemical Looping Combustion (CLC) process, providing a concentrated stream of CO₂ that is ready for transport and permanent storage.

What has the project done in terms of activities?
The project had the following main activities:
• Testing CLC with waste-derived fuel in the 150 kW CLC pilot unit of SINTEF Energy Research, using oxygen-carrier materials based on cheap minerals (ilmenite and manganese oxide).
• Evaluate possible re-use, or alternative use, of spent oxygen carrier materials.
• Perform a techno-economic study and LCA for a possible plant, and benchmark with other technologies.

What has the project achieved? Did the project achieve its objective?
The pilot tests showed that conversion of waste-derived fuel in a CLC process, with cheap natural minerals (ilmenite and manganese oxide) as oxygen carrier materials, is feasible. Operation was stable and the results very promising, even slightly better than what was achieved with biomass, a reference fuel much more tested in CLC. The results showed that a CO₂ capture rate of more than 95 % can be achieved.

Spent oxygen carrier material from CLC was not so beneficial for use in the titanium dioxide production process. It was more difficult to process the spent material to titanium dioxide than from fresh unused ilmenite. However, the titanium dioxide process produces a waste material stream. This was tested in lab-scale and can in fact be a possible material to be used as oxygen carrier in CLC.
The techno-economic assessment showed that the CLC plant had better efficiency and lower CO₂ avoidance cost than the reference plants evaluated in the study (with post-combustion calcium looping and amine, and same plant capacity). The LCA study showed that the CLC-plant had better score than the reference plants on the indicator “climate change”.

The main objective has been achieved and it is shown that waste-derived fuels can be converted with CLC technology and provide efficient CO₂ capture. The “CLC-SRF” project has been a feasibility study with limited extent. The work is now taken further in a new project as described below. This will bring more detailed results and evaluations, and further contribute to assurance of the promising results from the “CLC-SRF” results.

Future plans?
This project (feasibility study) represents the first stage to develop CLC as a possible conversion and capture-technology for waste-derived fuels. As a second stage, it was applied for a project to the ACT3 call. This was granted and the work is now being carried out in the project “LOUISE” (https://act-louise.net/). This project includes more countries (Germany, Norway, Turkey, and Greece) and more partners, including one large plant manufacturer. It is planned pilot tests up to 1 MW scale. The project will also prepare for demonstration at 10 – 30 MW scale by establishing the design for such a plant. This is an industrially relevant scale and is planned as a stage three I the development towards a commercial technology.