Catalytic Fast Pyrolysis of Pine Wood: Effect of Successive Catalyst Regeneration

Abstract

The main product of biomass fast pyrolysis is a liquid mixture of numerous organic molecules with water that is usually called pyrolysis oil or bio-oil. The research discussed in this paper was meant (1) to validate a new, semicontinuously operated pyrolysis setup and (2) to investigate the effect of a repeatedly regenerated ZSM-5-based catalyst (eight reaction/ regeneration cycles in total) on the yields and compositions of the pyrolysis products in relation to the applied process conditions and on the catalyst itself. The reliability of the setup has been proven by multiple repetition of noncatalytic and catalytic (in situ) pyrolysis experiments for pine wood at 500 °C under identical conditions. As a result, the mass balance closures for all experiments varied from 92 to 99 wt %, while the scatter in measured data was always less than 5%. Changes in the performance of the repeatedly regenerated catalyst have been observed via detailed analysis of the bio-oil (GC × GC-FID and GC × GC-TOF-MS, Karl Fischer), the noncondensable gases (micro-GC), and the carbonaceous solids (elemental analyzer, BET surface area). Along the reaction/regeneration sequence, the yield of organics increased, while water, carbonaceous solids, and noncondensable gases decreased. Trends in pyrolysis product yields converging to that of noncatalytic levels were observed, which revealed that the influence of the catalyst slowly declined. The main observation was that the catalyst partially loses its activity in terms of the product distribution along the reaction/regeneration sequence, while retaining sufficient activity in producing the target chemical compounds.

Optimization of bio-oil yields by demineralization of low quality biomass

“…Demineralization can be beneficial for other reasons as well; inorganic matter in bio-oil, originating from the biomass feedstock, catalyzes deleterious chemical reactions during storage, resulting in reduced stability [7e9]. In addition, in the case of fast pyrolysis processes with in-situ catalytic upgrading of the pyrolysis vapors, inorganic matter from the biomass feedstock is deposited on the catalyst, leading to deactivation [10,11].…”

Modification and regeneration of HZSM-5 catalyst in microwave assisted catalytic fast pyrolysis of mushroom waste

“…Previous studies related to the modification and regeneration of catalysts by various techniques were reported intensively [10][11][12][13][14]. For the modification of HZSM-5, Huang et al [15] modified HZSM-5 zeolites by CuO and MoO 3 for the thermal conversion of pine sawdust, and they indicated that Mo(3%)-Cu(3%)/HZSM-5 treatment promoted the highest yield of C 6 $ C 12 hydrocarbons.…”

Catalytic Fast Pyrolysis: Influencing Bio‐Oil Quality with the Catalyst‐to‐Biomass Ratio

“…Theo verall yield of organic liquids exhibited ad ecreasing trend, and more of the biomass feedstock was converted into other product fractions at higherC/B ratios.Asthe pyrolysis temperature and the fluidization conditions were not varied between the different experiments,o ne would expectt hat the initial thermal decomposition of biomass would not be affected by an increase of the C/B ratio.T his also relies on an underlying assumption that similar yields of char are obtained under non-catalytic and catalytic operation. [31] Based on this,t he increase in the combined char/coke yield should be primarily accountable to increased formationo fc oke.T he variationo ft he C/B ratio did not cause as ignificant changeo fh ow the organic liquids were divided between the CFP bio-oil and the aqueous phase.A pproximately 75 %o ft he overall organics were in the CFP bio-oilp roduct and 25 %r emained in the aqueous phase ( Table 1).…”

“…As the pyrolysis temperature and the fluidization conditions were not varied between the different experiments, one would expect that the initial thermal decomposition of biomass would not be affected by an increase of the C/B ratio. This also relies on an underlying assumption that similar yields of char are obtained under non‐catalytic and catalytic operation . Based on this, the increase in the combined char/coke yield should be primarily accountable to increased formation of coke.…”