Syngas production via coal char-CO2 fluidized bed gasification and the effect on the performance of LSCFN//LSGM//LSCFN solid oxide fuel cell

Fluidized bed reactor is widely used in coal char-CO2 gasification. In this work, the production of syngas by using a fluidized bed gasification technique was first investigated and then the effect of the produced syngas on the performance of the solid oxide fuel cell with a configuration of La0.4Sr0.6Co0.2Fe0.7Nb0.1O3-δ//La0.8Sr0.2Ga0.83Mg0.17O3-δ//La0.4Sr0.6Co0.2Fe0.7Nb0.1O3-δ(LSCFN//LSGM//LSCFN) was studied. During the syngas production, we found that the volume fraction of CO increased with the increment of gasification temperature, and it reached a maximum value of 88.8%, corresponding to a composition of 0.76% H2, 88.8% CO, and 10.44% CO2, when the ratio of oxygen mass flow rate to that of coal char (MO2/Mchar) increased to 0.29. In the following utilization of the produced syngas in solid oxide fuel cells, it was found that the increasing CO volume fraction in the syngas results in a gradual increase of the peak power density of the LSCFN//LSGM//LSCFN cell. The maximum peak power density of 410 mW/cm2 was achieved for the syngas produced at 0.29 of MO2/Mchar. In the stability test, the cell voltage decreased by 4% at a constant current density of 0.475 A/cm2 after 54 h when fueled with the syngas with the composition of 0.76% H2, 88.8% CO, and 10.44% CO2. It reveals that a carbon deposition with the content of 13.66% in the anode is attributed to the cell performance degradation.