**4.4.2 Overall results**

Table 10 shows the overall results for pelletized PEFB at different air flow rates, in term of producer gas yield, fuel consumption rate and cold gas efficiency.


Table 10. Overall results for pelletized PEFB at different air flow rates in prototype gasifer

From Table 10, the maximum heating value of 6.99±0.29 MJ/Nm3 is observed at the air flow rate of 100 Nm3/hr which correspondances to the cold gas efficiency of 76.34 %. From the observation during the experiments, although at the air flow rate of 100 or 105 Nm3/hr the heating value of producer gas and the cold gas efficiency reach the maximum value, the producer gas was unstable and non-continuously formed. Instead, at the air flow rate of 110 Nm3/hr, the producer gas was continuously and uniformly generated. Therefore, for testing of using producer gas as fuel in the internal combustion engine-generator, the air flow rate of 110 Nm3/hr is selected as optimum operating condition.
