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 La_0.4Sr_0.6Co_0.2Fe_0.7Nb_0.1O_3-δ//La_0.8Sr_0.2Ga_0.83Mg_0.17O_3-δ//La_0.4Sr_0.6Co_0.2Fe_0.7Nb_0.1O_3-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 (M_O2/M_char) 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 M_O2/M_char. 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% CO_2. It reveals that a carbon deposition with the content of 13.66% in the anode is attributed to the cell performance degradation.