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 in situ 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.