Fast pyrolysis of Kraft lignin—Vapor cracking over various fixed-bed catalysts

Screening of pyrolysis reactions has been carried out with Kraft lignin and various catalysts applying the TI-mini fast pyrolyzer. Zeolite HZSM-5, FCC and Olivine in a small fixed bed were used as catalyst to investigate their influences on the pyrolysis reaction. The characteristics of catalytic pyrolysis reactions and final products were studied by varying reaction temperature and catalyst type. The TI-mini fast pyrolyzer is especially suitable to obtain quick mass balances of main products such as char, non-condensable gases and biocrude-oil. Their yields were evaluated and the collected biocrude-oil was further analyzed using GC–MS/FID. Depending on the various catalysts as well as different pyrolysis temperatures, the overall distribution of the three main product categories and the portions of certain chemical compounds were increased or decreased. To scrutinize the catalytic effect and to highlight the severity of lignin degradation, size exclusion chromatography (SEC) was performed from extracts of the solid residue.

► The screening of pyrolysis reactions was carried out for Kraft lignin with various catalysts.
► The biocrude-oil yields were evaluated and the biocrude-oil was further analyzed using GC/MS/FID.
► Also, size exclusion chromatography (SEC) was performed for extracts from the solid residue.
► The minimum and maximum yields of biocrude-oil were 10.07% and 15.99%, respectively.
► HZSM-5 and FCC show the remarkable catalytic effects on the pyrolysis characteristics.