Investigation of Pretreated Switchgrass, Corn Stover, and Hardwood Fuels in Direct Carbon Fuel Cells

摘要

A variety of fuels were evaluated in an electrolyte-supported Direct Carbon Fuel Cell (DCFC). Thesecells consisted of a planar, 8 mol% Y2O3-ZrO2 (YSZ) electrolyte with a multilayer(La0.6Sr0.4)0.98(Co0.2Fe0.8)1O3-. (LSCF) cathode. Double gadolinium-doped ceria (GDC) catalyst layerswith different porosity levels were deposited onto the anode side. The fuels evaluated in this workwere carbon black, bituminous coal (Kingwood, WV) and various biomasses, all mixed with a 6% volLi (53%wt) - K (57%wt) carbonate system. The biomasses were switchgrass, corn stover, andhardwood. Switchgrass was utilized both raw and at different levels of thermal pretreatment (torrefiedat 250C and pyrolyzed at 900C under inert atmosphere). It was found that torrefied switchgrass-2 presented the highest maximum power density at 800C (120.5 mWm ), as well as the lowest anodepolarization resistance (0.135 m) when tested in the DCFC. Therefore, corn stover and hardwoodwere studied just as torrefacted fuels (250C under inert atmosphere) in the DCFC. Particulate surfacearea, proximate and ultimate chemical analyses, weight loss upon thermal pretreatment, scanningelectron microscopy (SEM), and inductively coupled plasma-optical emission spectroscopy (ICP-OES)of digested biomass samples were carried out on the various fuels to explain differences inperformance and anode polarization resistance. A common feature of the three torrefied biomasses is-2 the similar power densities measured at 0.7 V and 800C, with values of 115 mWcm for switchgrass,-2 -2112 mWcm for hardwood, and 105 mWcm for corn stover.