An experimental investigation of a direct burning of crude Jatropha oil (CJO) and pitch in a commercial boiler system

Abstract

We conducted a test of a direct burning of crude Jatropha oil (CJO) and pitch in a commercial boiler system. The fuel, crude Jatropha oil is not biodiesel which comes from transesterification process of bio oil, but it is pure plant oil like cooking oil. The higher heating value (HHV) of the CJO is 39.3 MJ/kg (9380 kcal/kg) and is lower than that of commercial heating oil, 44.0 MJ/kg. The kinematic viscosity of CJO is 36.2 mm2/s at 40 °C and 8.0 mm2/s at 100 °C. The burner used in the test is a commercial burner for a commercial heating oil and its capacity is 140 kW (120,000 kcal/h).We did a preliminary test whether the combustion is stable or not. The preliminary test was a kind of open air combustion test using the commercial burner with crude Jatropha oil. We found that the combustion can be stable if the crude Jatropha oil temperature is higher than 90 °C. We measured the flue gas concentration by using a gas analyzer. The NOx concentration of crude Jatropha oil is 80 ∼ 100 ppm and CO concentration is nearly 0 ppm at flue gas O2 concentration of 2.5 and 4.5%. We also tested a pitch combustion and the result shows that the NOx concentration of pitch is about 90 ∼ 110 ppm and CO concentration is below 30 ppm at flue gas O2 concentration of 2.5 and 4.5%. As a reference data, combustion of heating oil was conducted. The NOx concentration of heating oil is about 80 ppm which is the lowest value of tested fuels.