针对生物柴油氧化安定性较差、NOx排放偏高的情况,添加抗氧化剂(BHA)对生物柴油进行燃料改性,分析了抗氧化剂对生物柴油氧化安定性的影响,讨论了改性前、后生物柴油粘度随温度的变化规律。测量了高压共轨柴油机燃烧改性生物柴油的排放污染物随转速、负荷的变化规律。探讨了抗氧化剂改善生物柴油碳烟、NOx排放的作用机理。研究结果表明:燃料改性后,生物柴油的氧化安定性大幅度提高,燃油粘度略有降低;发动机的碳烟、NOx排放均明显下降,特别是在中、高负荷时效果显著;燃烧过程中抗氧化剂抑制了脂肪酸长链分子的高温裂解,促进了自由基的淬熄效应,由此改变了碳烟与NOx排放之间此消彼长的关系。
Because of the poor oxidation stability and the high NOx emissions,biodiesel fuel was redesigned by adding anti-oxidants.The oxidation stability and viscosity of the biodiesel have been measured and analyzed.The engine experiment was conducted and it was fueled by biodiesel and BHA/biodiesel,NOxemission and smoke were measured.The mechanism of anti-oxidants to decrease the smoke,NOx emission was discussed.The results showed that BHA additive was a high effective antioxidant of biodiesel,the viscosity of biodiesel was decreased slightly;and the emission smoke and NOx was decreased significantly,especially at the high load condition.Anti-oxidants can restrain the high-temperature dissociation of long-chain fatty acid molecules during the combustion process,and it can promote the quenching effects of free radical.Also,it can change the "trade-off" tradition relationship between smoke and NOx emissions.