Hydrogen-Enriched Syngas from Biomass Steam Gasification for Use in Land-Based Gas Turbine Engines - Novel Combustion Concepts for Sustainable Energy Development - page 85

house gas emissions leads to a number of national governments to provide incentives
in support of the development of alternative energy sources, making renewable
sources of energy as the fastest growing in the outlook.
Gas turbines have emerged as the best means of transforming heat

into

mechanical energy and are now key components of the most ef cient electrical

generating systems. Hydraulic fracturing, or fracking, has increased the shale gas
production, which accelerated the use of gas turbines for power production in lieu
of coal power. However, many countries such as India and China do not have
access to the shale gas and as a result will depend on alternative sources such as the
syngas produced from either coal or biomass gasi cation. The more environmen-

tally accepted solution would be syngas that is produced from biomass gasi cation.

To be considered interchangeable with conventional fossil fuels (natural gas) and to
ensure maximum flexibility, syngas heating value needs to be above 11 MJ/m 3 .

A high hydrocarbon content corresponds to a higher heating value for the syngas.
Hence, a hydrogen-enriched synthesis gas with a higher heating value will help to
mitigate the use of natural gas in land-based gas turbine applications. Hence, the
subject of this paper is to present a cost effective means of biomass-derived syn-
thesis gas production that is suitable for use in land-based gas turbines for power
production.
The preferred feedstock for the current purpose is the cellulosic biomass that
includes plant matters such as wood chips, switchgrass, wheat straw, corn stovers,
sorghum, oilseed crop meals, and agriculture wastes. Cellulosic biomass is an
advantageous feedstock because it is not an edible food crop feedstock. The cellu-
losic biomass consists primarily of cellulose, hemicellulose, and lignin, and these
compounds pose signi

fl

cant challenges to conventional chemical and microbial
processing methods. The process described in this paper can utilize different types of
cellulosic biomass including lignocellulosic biomass and will ensure a continuous
and renewable feedstock supply that is affordable. Because of the ability to convert
cellulosic biomass, the proposed process has a signi

cant advantage in full plant
utilization. Other technologies have not addressed this important consideration.

1.1 Dual Fluidized Bed (DFB) Steam Gasi cation

Gasi cation is a well-proven technology that has been employed in various forms

for almost 200 years (Klass 1998 ). It is essentially an oxygen limited thermo-
chemical conversion of carbonaceous material to a useable gaseous fuel, synthesis
gas or consisting primarily of hydrogen (H 2 ) and carbon monoxide (CO),

with lesser amounts of carbon dioxide (CO 2 ), methane (CH 4 ), higher hydrocarbons
(C 2 +), water (H 2 O), and nitrogen (N 2 ). The oxidant used can be air, pure oxygen, or
steam. Air-based gasi

“ syngas ”

ers typically produce a product gas containing relatively high
concentration of nitrogen with a low heating value (LHV) between 3 and 5 kJ/kg
(4 7 MJ/Nm 3 ) 2 . Steam-based gasi

ers, on the other hand, produced a product gas
containing relatively high concentration of hydrogen and CO with heating values

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