Hydrogen-Enriched Syngas from Biomass Steam Gasification for Use in Land-Based Gas Turbine Engines - Novel Combustion Concepts for Sustainable Energy Development - page 92

Table 3 Biomass feedstock
Analysis

Parameter Value Units

C 51.34 Moist. free wt%

O 42.50 Moist. free wt%

H 5.98 Moist. free wt%

N 0.17 Moist. free wt%

S <0.01 Moist. free wt%

Ash <0.6 Moist. free wt%

Moisture 5.82 wt%

LHV 20,242 kJ/kg

losses. The calibrated variable transformers have a relative error of 2.5 %. The
current draw of the heaters is measured by ammeters that have a relative error of
5.0 %. Next, the steam generator and superheaters are started. The steam flow rate is

determined by measuring the liquid feed rate (relative error of 4.3 %) which
intermittently feeds the boiler. The

fl

flow rates used for calculations are averaged
over an hour of testing. The electrical load of the boiler and superheaters is not
directly measured, but calculated using the enthalpy gain from liquid water at
standard temperature and pressure to its state entering the settling chamber.
The calibrated metering feeder controls the biomass feed rate. The feeder has a
measured error of 6.9 %, which is caused by variations in pellet size, hopper

fl

ll
height, and pellet structural integrity. The pellets contain no binders and tend to
break up when agitated. The biomass feedstock used for all testing is north Florida
pine. Table 3 shows the chemical analysis for the feedstock. Green Circle Bio
Energy manufactures the pellets locally from native trees. The pellets have a low
ash content of less than 0.6 %, which helps prevent conglomeration in the reactor.
After gasi cation and cooling, the syngas mixture is analyzed by an Agilent Micro

GC 3000, which has a relative error of 6.4 %. The chromatograph detects the dry
relative concentrations of all compounds with atomic mass less than propylene
(C 3 H 6 ). During operation, samples are drawn from the produced stream every 4 min
for analysis. Once the syngas is

filtered and analyzed, the volume fl flow rate is then

measured using a custom venturi type flow meter that has a relative error of 5.3 %.

Another K-type thermocouple measures the gas density at the venturi

fl

fl ow meter.

3 Results and Discussion

To verify gasi ciency

are compared to published data. Figure 5 compares the hydrogen concentration
found in this study to published results at similar steam-to-biomass (S/B) ratios and
residence times. The agreement in the data con

er results, the syngas hydrogen concentration and cold gas ef

rms gasi er operation and the gas

analysis techniques used in this study.