Hydrogen-Enriched Syngas from Biomass Steam Gasification for Use in Land-Based Gas Turbine Engines - Novel Combustion Concepts for Sustainable Energy Development - page 104

conditions, but little information exists on the thermal conversion ef ciency during

these conditions. Researchers have expressed doubt in steam gasi cation citing its

large energy demand.
The syngas produced during cation had a maximum

hydrogen concentration of 51 mol%. During this test, the conversion of energy to
syngas heating content and hydrogen heat content was 58 and 26 %, respectively.
These values were obtained at the highest temperature tested (850

fl fluidized bed steam gasi

C), a high
steam-to-biomass ratio (2.9 by weight), and a high gas residence time in the reactor
(4.1 s). A signi

°

cant fraction of energy was needed to generate steam during this
test, which limited the thermal conversion of energy to syngas. At the lowest steam-
to-biomass ratio tested (0.75), the conversion of energy to syngas heat content was
68 % but the conversion to hydrogen was only 20 %. This was due to the relatively
low hydrogen concentration (38 mol%).
Steam gasi cation with CaO produced the highest H 2 concentrations tested in

this study (69 mol%). The maximum thermal conversion of energy to syngas heat
content and hydrogen heat content was 47 and 27 %, respectively. The conversion
ef ciencies were lower than those observed during inert-bed testing because at the

optimal temperature for CaO gasi

cation (700 ° C), and char conversion was low.

During CaO regeneration, the char was gasi ed, producing a syngas stream with

over 80 mol% hydrogen. The energy produced during regeneration equaled the
energy requirement during this phase.

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