Feasibility analysis of H2 production by calcium looping process based on coal gasification in a transport reactor

Abstract

Calcium looping process (CLP) is one kind of carbonaceous material gasification process applied in the H2 rich syngas production and CO2 separation. In this research, a transport reactor with efficient heat and mass transfer and better gas and solid mixing was applied as the gasifier to produce H2 rich syngas with in situ CO2 capture. The primary objective of this research was to investigate the feasible operation conditions for gasifier and entire looping process. The gasification process was analyzed by model based on the reactor hydrodynamics and chemical kinetics. Influences of operating parameters, i.e. temperature, steam to carbon ratio and pressure, on the reactor hydrodynamics, reaction rates and conversion ratios, syngas flow and compositions, steam and power consumption were given and discussed. Feasible operation conditions for gasifier and system configuration were proposed according to the heat and power balance, H2 yield and systematic energy conversion efficiency. Simulation results indicated that feasible operation with H2 and power co-production can be achieved with the gasification temperature of 1273 K, pressure of 0.9 MPa, steam to carbon ratio of 1.8 and CaO to carbon ratio of 1.0. For this feasible operation, the H2 output exceeded 0.78 Nm3 per kg coal and energy conversion efficiency was higher than 40%.