Effect of the catalyst in fluid bed catalytic hydropyrolysis

Catalytic hydropyrolysis of beech wood was conducted in a fluid bed reactor followed by a hydrodeoxygenation reactor with a sulfided NiMo/Al2O3 catalyst. In order to evaluate the effect of the catalyst in the fluid bed reactor, six different bed materials were tested. Conducting the hydropyrolysis using only the catalyst support materials MgAl2O4 or zeolite mixed with Al2O3 (H-ZSM-5-Al2O3) gave a high char and coke yield (18.7-21.1 wt.% dry ash free (daf)), CO and CO2 (18.9 and 20.0 wt.% daf), and low yield of condensed organics and C4+ gasses (17.8-20.4 wt.% daf).

Using the supported catalysts CoMo/MgAl2O4 or NiMo/H-ZSM-5-Al2O3 significantly decreased the char yield to between 11.4 and 13.1 wt.% daf, while the condensed organics and C4+ yield increased to 21.5 wt.% daf for the CoMo/MgAl2O4 and 24.0 wt.% daf for the NiMo/H-ZSM-5-Al2O3. As an alternative to the (commercial) supported catalysts, a cheap natural mineral bog iron was tested as catalyst and gave a condensed organics and C4+ yield of 22.8 wt.% daf when pre-sulfiding the bog iron, while the yield was 24.7 wt.% daf when the bog iron was used un-sulfided, but reduced prior to the experiment.

This indicates that bog iron is the most suitable catalyst in the fluid bed reactor.