Technical benefits of using methane as a pyrolysis medium for catalytic pyrolysis of Kraft lignin

Catalytic fast pyrolysis of low sulfonated Kraft lignin was performed under different atmospheric environments such as N-2, CH4, and the gas derived from CH4 decomposition (CH4-D). The use of Zn-or Mo-loaded HZSM-5 as catalyst led to a higher pyrolytic oil yield compared to parent HZSM-5 in CH4 and CH4-D atmospheres. The yields of benzene, toluene, and xylenes were increased by the synergistic effects from metal loading, higher H/C(eff )ratio, higher acidity, and CH4 activation. The enhanced CH4 activation via metal loading resulted in higher methylation of alkyl moieties and 33% increase in the total yield of benzene, toluene, and xylenes in comparison to parent HZSM-5. A higher H/C-eff ratio of 6 via CH4 decomposition led to the formation of a hydro-pyrolysis environment. Moreover, the CH4-D environment showed H-2/CH4 ratio of 0.36 in the product gas which warranted the presence of more H-2 under the CH4-D pyrolysis environment.

Automated summary

The catalytic fast pyrolysis of low sulfonated Kraft lignin was studied under different atmospheric environments. The use of Zn-or Mo-loaded HZSM-5 catalyst resulted in higher pyrolytic oil yield and increased benzene, toluene, and xylenes yields. The enhanced CH4 activation via metal loading and the formation of a hydro-pyrolysis environment through CH4 decomposition were observed. The CH4-D environment showed a higher presence of H-2 in the product gas.