Thermodynamic modelling of integrated carbon capture and utilisation process with CaO-based sorbents in a fixed-bed reactor

The global emission of CO2 through fossil fuel combustion is still increasing, which is a major challenge for the international community. An integrated carbon capture and utilisation (ICCU) process with a CaO-based sorbent is a promising alternative to effectively reduce emissions. In this work, a comparative thermodynamic analysis of two CaO-based sorbents (commercial and sol-gel CaO) was performed for one cycle of ICCU. In addition, the influence of temperature was investigated from 600 to 750 degrees C in terms of the degree of CO2 conversion. Thermodynamic calculations were based on the actual gas composition and developed model, where heat consumption and entropy generation were calculated. The results indicate that the degree of CO2 conversion decreased from 84.6 to 41.2% and from 84.1 to 62.4% for the sol-gel and commercial material, respectively, as the temperatures increased. Furthermore, the total heat consumption during one cycle decreased with higher temperatures. The total amount of consumed heat decreased from 19.1 to 5.9 kJ/g and from 24.7 to 5.4 kJ/g for sol-gel and commercial CaO, respectively. Although commercial CaO always requires more heat during one cycle. Moreover, for both materials, the lowest generation of entropy was calculated at 650 degrees C with values of 9.5 and 10.1 J/g.K for the sol-gel and the commercial CaO, respectively. At all temperatures, the commercial CaO generated a greater entropy.

Automated summary

The global increase in CO2 emissions from fossil fuel combustion is a major challenge for the international community. An integrated carbon capture and utilization process (ICCU) using a CaO-based sorbent shows promise in reducing emissions. This study thermodynamically analyzed the performance of two CaO-based sorbents (commercial and sol-gel CaO) in one ICCU cycle and investigated the influence of temperature on CO2 conversion. The results revealed that as temperatures increased, CO2 conversion and total heat consumption decreased for both sorbents. Furthermore, the lowest entropy generation occurred at 650 degrees C for both sorbents.