D8.2 Oxyfuel suspension calciner test results

This deliverable (D8.2) summarizes the calcination tests conducted within work package 8 (WP8) of CEMCAP project. The main objective was to perform reference air and oxyfuel calcination tests, to evaluate a possible shift of calcination temperature in a CO2-rich oxyfuel environment. The oxyfuel tests were further extended to evaluate the most industrially relevant operational parameters like temperature, residence time and atmosphere. The test results show the average shift of 50-70 K for oxyfuel calcination, which is in line with studies publically available. Provided the higher temperature, reference calcination level (≥90 %) could be achieved within existing suspension calciner conditions. For the test conducted with fuel addition, the reference calcination level (≥90%) for air case was achieved at temperature of 860°C (similar to the temperature reported for industrial calciner), while for oxyfuel case the temperature level up to 940°C was required to achieve similar level of calcination.
The evident problem of amplified formation of deposits at higher temperatures in the calciner could not be linked to increase sintering of raw meal itself. From that point of view retrofitting of existing calciners to oxyfuel operation seems possible. However, to clarify the deposit issue, there should be invested some effort to investigate the influence of ashes derived from burning (alternative) calciner fuel at oxyfuel calcination temperature. Further research and development work should be focused on pilot scale trials in real calciner (hardware) configurations and modeling studies for retrofitting options.