Real-Time Study of Noxious Gas Emissions and Combustion Efficiency of Blended Mixtures of Neem Biodiesel and Petrodiesel

Neem biodiesel is currently being explored as a future biofuel and was extracted chemically from the vegetable oil. Many of its properties are still under investigation and our aim was to study its noxious-gas emission profiles from blends with regular petroleum diesel. The distinct advantage of a real-time study is acquisition of <i>in situ</i> data on the combustion behavior of gas components with actual progression of time. Mixtures of neem biodiesel and petroleum diesel corresponding to neem additives of 5%, 10%, 15% and 25% were tested for combustion efficiency and emitted gases using a high-performance gas analyzer. Our study, therefore, investigated the overall efficiency of the combustion process linked to emissions of the following gases: O₂, CO₂, NO, NO_x and SO₂. The results for the 95/5% blend compared to the neat sample were most promising and showed no serious change in performance efficiency (<2%). NO/NO_x emission trends displayed maxima/minima, suggestive of interconvertible chemical reactivity. Declining CO and SO₂ emissions were consistent with rapid chemical conversion. The CO and SO₂ concentrations fell well below the toxic atmospheric limits in less than 300 s. The results are generally encouraging for blends below 10%. The potential environmental impact of the study is discussed.