Steam Reforming of the Bio-Oil Aqueous Fraction in a Fluidized Bed Reactor with in Situ CO₂ Capture

Abstract

The effect of CO 2 capture in hydrogen production by steam reforming of the bio-oil aqueous fraction was studied. The reforming and cracking activity of the adsorbent (dolomite) and the relationship between these reactions and those corresponding to the catalyst (reforming and water gas shift (WGS)) were considered. The experiments were conducted in a two-step system with the first step at 300 °C for pyrolytic lignin retention. The remaining volatiles were reformed in a subsequent fluidized bed reactor on a Ni/La 2 O 3 −α-Al 2 O 3 catalyst. A suitable balance was stricken between the reforming and WGS reactions, on the one side, and the cracking and coke formation reactions, on the other side, at 600 °C for catalyst/ dolomite mass ratios ≥0.17. At this temperature and space-time of 0.45 g catalyst h (g bio-oil ) −1 , bio-oil was fully converted and the H 2 yield was around 99% throughout the CO 2 capture step. Catalyst deactivation was very low because the cracking hydrocarbon products (coke precursors) were reformed.

A sequential process for hydrogen production based on continuous HDPE fast pyrolysis and in-line steam reforming

“…The better performance of the fluidized bed reactor for the minimization of coke formation has been previously reported in the reforming of pyrolysis oils derived from both biomass [26,27] and plastics [28]. …”

Coke formation and deactivation during catalytic reforming of biomass and waste pyrolysis products: A review

“…La2O3 has also been reported to promote active phase dispersion and coke gasification, the latter by means of the formation of metal-promoter species [70]. Additionally, CO2 adsorbents such as CaO or dolomite are widely known to promote the WGS reaction, and are used both in situ (in the reforming reactor) [71] or in a sequential step [72], although they undergo a rapid and partially irreversible deactivation.…”

Hydrogen production from catalytic reforming of the aqueous fraction of pyrolysis bio-oil with modified Ni–Al catalysts

“…Thermal treatment of raw biomass before the catalytic reforming stage was reported by Valle et al [28] in order to separate pyrolytic lignin which is mainly responsible for coke formation. The use of fluidized beds has also been reported to attenuate coke deposition on catalysts [29]. A current-enhanced catalytic steam reforming method has been proposed which reported less coke formation compared with the normal reforming method [12].…”