The samples are combusted in the EA and the produced CO2 is adsorbed in a column filled with zeolite material. Later the CO2 is thermally released from the zeolite trap and transferred to the reactor by gas expansion. Hydrogen is finally added to reduce the CO2 in the reactor at a temperature of 580°C in presence of an iron catalyst.
The entire system with valves, ovens, temperature and pressure sensors is computer controlled. A program runs through all consecutive steps when processing a sample: catalyst preconditioning, sample combustion in the EA and CO2 trapping, thermal CO2 release from the trap into the reactor, and finally the graphitization reaction itself.