Nicloas Vin, R&D engineer at IFPEN presented the primary test results on the CHEERS project based on the demo unit outputs as of the seminar date. The presentation touched on the timeframe from January of 2022, where the construction of the demo unit started. Aside from the rapid construction over 11 months to erect the 44-meter-high demo unit, it was done so with no accident or incident. This holds true even through the operation of the demo unit as well as repair works that it has undergone since the first start-up of the plant on 6th of June 2023.
The oxygen carrier, Ilmenite, required pre-oxidation to ensure agglomeration is avoided. Agglomeration may occur mainly for reduced oxygen carrier particles in dead zones of the demo unit. Confirmed by experiments in a small-scale muffle furnace, pre-oxidation at 800 degrees Celsius avoids agglomeration, and also positively impacting oxygen carrier circulation. 75 tons of ilmenite was pre-oxidised in the fuel reactor.
The circulation of the oxygen carrier is crucial and complex. As a solid consisting of fine particles, controlling its flow rate across the different parts of the demo unit requires pneumatic valves realized by the L-valve. The three valves in the demo unit (X101, X102 and X103) control the oxygen carrier flow from air reactor to fuel reactor and reverse. The presentation highlighted the solid flow rates in the valves function of temperature and pressure.
The presentation also touched upon a challenge encountered with the manhole refractory. The fuel reactor reached significant temperatures at which some slugging solid regime occurred, with large build up of air bubbles in the start-up phase, resulting in the refractory manhole protection to fall down in the reactor. This was solved by improving the tightening of the refractory manhole by providing reinforcement via 4 melded metal supports.
The demo unit thus far has achieved the first validation of the CLC technology via L-valve functioning. Significant data acquisition of the working of the demo unit thus far sets the team up for the next challenges. Looking ahead, the team loops to complete solid circulation and L-valve calibration at 800 to 900 degrees, validation of heat losses for autothermal CLC as well as testing CLC at the 2-4 MW scale. The teams working on the demo unit, both European and Chinese partners are confident and excited to move forward with the next steps for the demo unit.
For further information on the primary results from the CHEERS demo unit feel free to reach out.