Thermodynamic feasibility for molybdenum-based gaseous oxides assisted looping coal gasification and its derived power plant

Abstract

Coal utilization in chemical looping reactions is a promising approach for fuel conversion with inherent CO2 separation, but is also hindered by kinetic limitations between the solid fuel and conventional oxygen carriers. Molybdenum oxides are considered as alternative oxygen carriers in a “gaseous oxide assisted looping” strategy, which can potentially resolve the problems of slow reaction rate in fuel reactors and the difficulty of separating oxygen carriers from ash in air reactors. For the novel conception, it is necessary to specify the chemical looping process and evaluate the thermodynamic feasibility. So, a molybdenum-based gaseous oxide assisted looping coal gasification (MoCLCG) process is designed in this study. The suitable temperature conditions of individual reactors are determined by analyzing the redox reaction characteristics and physical properties of molybdenum oxides. Furthermore, to verify the systemic feasibility, the MoCLCG technology is integrated with a hybrid solid oxide fuel cell/steam turbine power plant, which obtains energy/exergy efficiencies of 39.38% (LHV) and 36.32%, respectively. The most influence factor in the system performance is the heating efficiency of electric heating furnace. An optimal mass ratio of Mo-based oxygen carrier to coal is obtained as 6.84 and exists to achieve high energy and CO2 emission reduction efficiencies, simultaneously.