Thermodynamic evaluation of a conceptual process for coal gasification coupled with chemical looping air separation

• The novel technology, coal gasification integrated with chemical looping air separation, is introduced.
• The energy efficiency of this integration process is analyzed in detail.
• Results indicate the feasibility of the process from a thermodynamics perspective.

For the pressing need to reduce oxygen production cost of coal gasification and to utilize carbon dioxde in an effective approach, this present work, from the view of thermodynamic perspective, presents a novel technique, i.e. coal gasification integrated with chemical looping air separation (CLAS). CLAS is expected to offset 1–3% of the energy penalty associated with the world-wide oxygen production technology, i.e., cryogenic air separation unit (CASU). The thermodynamic performances, as the conversion of metal oxides (Mn2O3/Mn3O4) of redox reactions, gasification gaseous compositions and cold gas efficiency (CGE) were the main subject of focus. The four major factors, air flow rate, reduction temperature, oxygen-to-coal ratio (O/C) and steam-to-coal ratio (S/C) appear to have significant impact on the performance of the whole process, therefore comprehensive investigations related to these variations have been reached. In parallel the exergy destruction analysis has also been involved.