Aqueous-phase reforming of renewable polyols for sustainable hydrogen production

G5 Doktorsavhandling (artikel)


Interna författare/redaktörer


Publikationens författare: Lidia I.Godina
Förläggare: Åbo Akademi
Publiceringsår: 2019
ISBN: 978-952-12-3778-2
eISBN: 978-952-12-3779-9


Abstrakt

Renewable biomass can be utilized for sustainable hydrogen production
via aqueousphase reforming (APR), which implies catalytic conversion of
aqueous solutions of alcohols and polyols over transition metals at
comparably low temperatures with formation of hydrogen, CO2, light
alkanes, and a number of products in the liquid phase.

The current work is devoted to studies of APR of several alcohols
and polyols and their technical mixtures over mono- and bimetallic
catalysts [I-IV, VII]. A realistic APR reaction network [I, VII] and a
kinetic model [V] were proposed, reactor modelling and process design
were performed in [V, VI], and techno-economical analysis of APR was
provided in [VI].

Propanol-1, propane-1,2-diol, glycerol, xylitol and sorbitol were
studied in APR over different Pt/C catalysts. Influence of feed
chirality was investigated for the first time in APR of sorbitol and
galactitol over Pt/Al2O3 catalyst. Conversion of the technical mixture
of sorbitol and mannitol was compared to commercial sorbitol in APR over
Pt/C. Mono- and bimetallic carbon-supported catalysts were compared in
terms of activity and selectivity in xylitol APR.

The reliability of the liquid-phase product analysis was
considerably improved. Plausible reaction pathways were proposed
according to the product distribution and discussed from a thermodynamic
point of view. Different reaction paths of 1,2-propanediol APR were
computationally screened on a Pt(111) model surface specifically
addressing the competition between C−H, O−H, and C−C bond cleavages.

Experimental data obtained in the xylitol APR was utilized for
reaction kinetics modeling, dynamic reactor simulation, and process
design development. The process can be considered as a self-sufficient
one, since the reactor heat demand is fully covered by the combustion of
alkanes produced in APR.

Simulation of in-situ phase equilibrium was based on the results of
the sorbitol APR. Process design of a hydrogen production plant with 500
kg/h capacity operating with sorbitol syrup was developed and
optimized. A detailed techno-economical analysis was performed for the
first time for estimation of hydrogen production price.


Senast uppdaterad 2019-09-12 vid 03:02