545 / 2018-09-25 20:31:19

The reactivity of cobalt aluminate in chemical looping steam reforming of guaiacol

生物质燃气 > 生物质燃气

Cobalt aluminate (CoAl2O4) nanopowders, which were used in a chemical looping steam reforming (CLSR) of guaiacol have been synthesized via chemical co-precipitation method using metallic nitrates of Cobalt and aluminate as starting materials and ammonium carbonate ((NH4)2CO3)) was used as a precipitating agent. Various characterization techniques including N2 adsorption-desorption (BET), X-ray diffraction (XRD) and scanning electron microscopy (SEM) were employed to investigate the physicochemical properties of the fresh and used OCs. The characterization showed that the catalyzer whose specific surface area reach 47.15m2/g is in spinel-type structure with the spherical-particle size in the range of 10~25nm. The reactivity and stability tests were conducted in a fixed-bed reactor. For the fixed-bed reactor configuration, the spinel is stationary and alternatively exposed to reacting and oxidizing conditions by periodically switching the feed gases. The guaiacol conservation of 96.35% , the H2 yield of 25 wt% and the H2 selectivity of 93.70% was obtained under the condition of 650℃ with steam/carbon ratio of 4.5 and WHSV=1.01-1 which indicates that the spinel shows the great reactivity. The main route of CLSR (CoAl2O4→Co/CoAl2O4) and air oxidation stage(Co/CoAl2O4→CoAl2O4) was detected by the XRD. Conservation of guaiacol had fallen to 75.16% due to the slight cementation after 10-cycle stability test.