3.13.1.1 Fuel properties

Ultimate and proximate analysis (on an as received basis) of the DB (separated solids) used as feedstock in the current gasification experiments are presented in Table 3.3. Using as received analysis (ar), dry and dry ash-free (DAF) values are calculated and reported. Also, empirical chemical formulae are presented in Table 3.3 for gasification of DAF DB. Air gasification of DAF DB at ER > 5.8 (or A:F < 0.87) implies insufficient oxygen for the reaction (C + %O2 ^ CO) and hence, incomplete conversion of char, which means char as byproduct. On the other hand, at ER < 5.8 (or A:F > 0.87) there is more oxygen than that required for the conversion of all FC to CO and the FC could be gasified completely to CO and CO2. However, in gasification processes where the reaction time is not infinity (not ideal), incomplete conversion of char can be possible even with ER < 5.8.

3.13.1.2 Experimental results and discussion

To estimate the uncertainty in gas composition, standard deviation was determined for the data. The uncertainty for each gas was calculated as the ratio between the standard deviation and the average value measured. Additionally, the uncertainty of the temperatures was estimated as the ratio between the uncertainty of the device (±1.5°C) and the measured value. In general, the gas composition values fluctuated within ~15% and the temperature values within ~0.55% of the average value measured.