Biomass-to-hydrogen via fast pyrolysis and catalytic steam reforming
- National Renewable Energy Lab., Golden, CO (United States); and others
Pyrolysis of lignocellulosic biomass and reforming the pyroligneous oils is being studied as a strategy for producing hydrogen. Novel technologies for the rapid pyrolysis of biomass have been developed in the past decade. They provide compact and efficient systems to transform biomass into vapors that are condensed to oils, with yields as high as 75-80 wt.% of the anhydrous biomass. This {open_quotes}bio-oil{close_quotes} is a mixture of aldehydes, alcohols, acids, oligomers from the constitutive carbohydrates and lignin, and some water derived from the dehydration reactions. Hydrogen can be produced by reforming the bio-oil or its fractions with steam. A process of this nature has the potential to be cost competitive with conventional means of producing hydrogen. The reforming facility can be designed to handle alternate feedstocks, such as natural gas and naphtha, if necessary. Thermodynamic modeling of the major constituents of the bio-oil has shown that reforming is possible within a wide range of temperatures and steam-to-carbon ratios. Existing catalytic data on the reforming of oxygenates have been studied to guide catalyst selection. Tests performed on a microreactor interfaced with a molecular beam mass spectrometer showed that, by proper selection of the process variables: temperature, steam-to-carbon ratio, gas hourly space velocity, and contact time, almost total conversion of carbon in the feed to CO and CO{sub 2} could be obtained. These tests also provided possible reaction mechanisms where thermal cracking competes with catalytic processes. Bench-scale, fixed bed reactor tests demonstrated high hydrogen yields from model compounds and carbohydrate-derived pyrolysis oil fractions. Reforming bio-oil or its fractions required proper dispersion of the liquid to avoid vapor-phase carbonization of the feed in the inlet to the reactor. A special spraying nozzle injector was designed and successfully tested with an aqueous fraction of bio-oil.
- Research Organization:
- National Renewable Energy Lab. (NREL), Golden, CO (United States)
- DOE Contract Number:
- AC36-83CH10093
- OSTI ID:
- 447155
- Report Number(s):
- NREL/CP-430-21968-Vol.1; CONF-9605195-Vol.1; ON: DE97000053; TRN: 97:001172-0024
- Resource Relation:
- Conference: 1996 annual hydrogen peer review for DOE, Miami, FL (United States), 1-3 May 1996; Other Information: PBD: Oct 1996; Related Information: Is Part Of Proceedings of the 1996 US DOE hydrogen program review. Volume 1; PB: 575 p.
- Country of Publication:
- United States
- Language:
- English
Similar Records
Biomass to hydrogen via fast pyrolysis and catalytic steam reforming of the pyrolysis oil or its fractions
Steam reforming of fast pyrolysis-derived aqueous phase oxygenates over Co, Ni, and Rh metals supported on MgAl2O4