Anthropogenic CO2 emissions are known to cause global warming, where in the earth average temperature increases. The global scientific community has acknowledged a 2°C threshold in the global temperature increase to avoid irreversible effects of climate change. This necessitates about 50% CO2 emission cuts by 2050 and 80% emission cuts by 2050 as targeted by the EU and the UK. The bulk of our energy supply comes from fossil fuels, with coal fired power plants being the single largest point source of CO2 emissions. One option to continually use fossil fuels and simultaneously meeting the emission reduction targets is to capture the CO2 and store it either underground or in deep sea beds. The process known as carbon capture and storage (CCS) has been proven to capture 90% of CO2 emissions.
State-of-art CO2 capture technologies based on the use of amine containing solvents give relatively high energy penalty when used in power production. In this project we are studying an alternative more efficient process utilizing solid adsorbents (Metal-organic frameworks, MOFs) that may have advantages both in energy requirements and in environmental impact.
In the present work two classes of MOFs namely CPO-27 (Coordination Polymer of Oslo) and UTSA-16 (University of Texas at San Antonio) are currently being studied for their CO2 adsorption potential, in order to be used in novel carbon capture applications. The project is basically divided into three parts namely: scale-up of synthesis of MOFs up to kilogram levels; characterization of the synthesized MOFs; and development of a vacuum swing adsorption process for identifying the best possible configurations for carbon capture. The project therefore involves the expertise of engineers who have the technical know-how of the requirements of carbon capture and thereby coordinating with chemists who can synthesize an adsorbent suitable for the process.
MOF powders and pellets were synthesized by SINTEF. The MOFs were then screened for CO2 capacity and kinetics at the University of Edinburgh (UoE). The results from the characterization showed that the adsorbents exhibited favourable characteristics in comparison with commercial adsorbents. Further experiments are being carried out to identify useful information in order to use the adsorbents for large scale CO2 capture. At present, carbon capture on a lab scale is being demonstrated by SINTEF using the shaped CPO-27-Ni adsorbent.
All these experimental results were used as inputs for the adsorption cycle simulator developed by UoE and CERTH. Detailed optimization studies will be carried out to after the project ends to predict the performance of an optimal process configuration which can separate most of the CO2 from flue gas at high purity and with reduced energy requirements.
The proposal aims to develop an international collaborative research programme under Topic 4 of the FENCO-NET call: New innovative CO2 capture technologies. The specific issues addressed in the proposal are:
1. Overall evaluation of new innovative CO2 c apture processes based on Metal Organic Framework (MOF) materials;
2. To synthesise (scale-up to kg quantities), characterise,, formulate and evaluate selected MOFs for vacuum swing (VSA) post-combustion capture;
3. To investigate and address adsorben t stability and efficiency in post-combustion carbon capture processes;
4. To investigate and model mass and heat transfer kinetics to enable accurate dynamic process simulations needed for the optimization of the carbon capture units with respect to en ergy efficiency and operational and capital costs.
The FENCO-NET call gives the unique opportunity of coordinating the significant research efforts in the partner institutions. SINTEF has the capability of preparing advanced MOFs which can also be scaled- up to produce formed materials for bench scale process testing. The UoE has developed new rapid screening techniques, specifically for post-combustion carbon capture and the close collaboration with SINTEF will accelerate further developments and provide essential stability data to direct novel material synthesis. Significant advances in this field can only be achieved if material and process development are combined. CERTH brings significant expertise in Vacuum Swing Adsorption (VSA) modelling, simulatio n, design and optimization and both the UoE and SINTEF have the capability of evaluating the integration of the novel carbon capture systems in power plants.