Influence of catalyst support type on silver poplar pyrolysis vapors: a Py/GC-MS study

Abstract

This study aimed to investigate the effect of catalyst support material type on the pyrolysis products of biomass. For this purpose, ZSM-5 was selected as a commercial catalyst support material, while bio-char obtained from biomass was selected as a sustainable support material. Silver poplar (SP) was used in both bio-char production and pyrolysis reactions. Primarily, biomass characterization was performed. It was determined that carbon content of SP is suitable for the production of porous carbonaceous material as 52.4%wt. In addition, the high volatile matter content (75.48%wt.) and the low ash content (9.38%wt.) showed that SP was a suitable raw material for pyrolysis method. Cobalt loading to ZSM-5 and biochar was applied by dry impregnation method. Cobalt was successfully loaded onto the support material with the dry impregnation method, which was used for the first time for metal loading to biochar. Thus, Co/SPB catalyst was produced that was both inexpensive and provided less waste water production compared to other methods has been obtained. Commercially purchased ZSM-5, biochar obtained from SP and their 15%wt. cobalt loaded forms were characterized using BET, XRD and ICP-OES techniques. When cobalt was loaded to support materials, the specific surface area of biochar increased from 2.07 m(2)/g to 95.29 m(2)/g, while the specific surface area of ZSM-5 decreased from 414.54 m(2)/g to 343.05 m(2)/g. Also, it was seen that the pore size decreased if metal was loaded on the support materials. The pore size of the Co/SPB and Co/HZSM-5 samples were 6.5 nm and 2.2 nm, respectively. According to the XRD analysis results, it was specified that the cobalt onto the catalyst surface was in the Co3O4 crystal structure. The ICP-OES results were also showed that cobalt has been successfully loaded onto the catalysts. A significant increase in the amount of alcohol in the bio-oil was specified with using the Co/SPB catalyst in the pyrolysis of SP. The alcohol content increased as the amount of Co/SPB catalyst increased from 10 wt% to 20 wt%. According to this result, Co/SPB catalyst can be used in the production of bio-alcohol from biomass. While Co/HZSM5 catalyst was used in the pyrolysis reactions of SP, an increase in aromatic and aliphatic hydrocarbon content was determined. Co/HZSM5 catalyst can be utilized in the production of valuable chemicals, commercially. In addition, oxygenated compounds, which were undesirable products in the evaluation of bio-oil as a bio-fuel, were reduced in the bio-oil with catalytic performance.