School of Mechanical Engineering, VIT University, Vellore, 632014, India.
Indian Institute of Technology (IIT), Hyderabad, India.
Environ Sci Pollut Res Int. 2018 Sep;25(25):25098-25114. doi: 10.1007/s11356-018-2574-1. Epub 2018 Jun 25.
Lemon peel oil (LPO) is considered to be a viable alternative fuel for diesel engine applications due to its wider availability, renewable nature, easy extraction process, almost equivalent calorific value as neat diesel, and low viscosity. The present work aims to investigate the effect of novel emulsified LPO in a diesel engine in order to reduce the NOx emission without compromising the engine performance. A new ionic surfactant is introduced in the present study, namely methyl-dihydroxy propyl imidazolium chloride due to its higher hydrophilic-lipophilic balance value which helps to prepare stable water in oil emulsion. Also, Span 80 has been selected as another suitable surfactant for water in oil emulsion. Four emulsified fuel samples have been prepared using LPO, water, and different concentrations of surfactants. All the fuel samples are tested for their stability through gravitational technique for 7 days. Among the emulsified samples, 92% LPO + 5% water + 2% Span 80 + 1% methyl-dihydroxy propyl imidazolium chloride by volume (LPOE2) and 93.5% LPO + 5% water + 1.5% surfactant Span 80 by volume (LPOE4) have showed better stability when compared to other emulsion fuel samples. It is also revealed that the stability of LPO emulsion is improved by the addition of two emulsions. The experimental results showed that the brake thermal efficiency of LPO emulsion is reduced to 29.87 from 34.58% of pure LPO at full load condition. Oxides of nitrogen emission and smoke emission are reduced by 21-32 and 6-15% for the LPO emulsion samples compared to pure LPO. Moreover, the diesel engine operation with emulsified form of LPO increases the HC emission about 0.1 g/kWh for LPOE4 and 0.15 g/kWh for LPOE2 fuels from 0.053 g/kW for pure LPO at maximum power output condition. The reformulation of LPO into emulsified form increases the CO emission by 25-53% compared to pure LPO. Moreover, the reformulation of LPO into emulsions has resulted in lower cylinder pressure and heat release rate compared to pure LPO and diesel fuels.
柠檬皮油（LPO）由于其更广泛的可用性、可再生性、易于提取的过程、几乎与纯柴油相等的热值以及低粘度，被认为是柴油机应用的一种可行替代燃料。本工作旨在研究新型乳化 LPO 在柴油机中的影响，以降低 NOx 排放，同时不影响发动机性能。本研究引入了一种新型离子表面活性剂，即甲基二羟丙基咪唑啉氯化物，由于其较高的亲水亲油平衡值，有助于制备稳定的油水乳液。此外，还选择了 Span 80 作为另一种适合油水乳液的表面活性剂。使用 LPO、水和不同浓度的表面活性剂制备了四种乳化燃料样品。通过重力技术对所有燃料样品进行了 7 天的稳定性测试。在乳化样品中，体积比为 92% LPO+5%水+2%Span 80+1%甲基二羟丙基咪唑啉氯化物（LPOE2）和体积比为 93.5% LPO+5%水+1.5%Span 80 的乳化燃料（LPOE4）的稳定性优于其他乳化燃料样品。还发现，两种乳化剂的添加可提高 LPO 乳状液的稳定性。实验结果表明，在全负荷条件下，LPO 乳状液的制动热效率从纯 LPO 的 34.58%降低到 29.87%。与纯 LPO 相比，LPO 乳状液样品的氮氧化物排放和烟度排放分别降低了 21-32%和 6-15%。此外，与纯 LPO 相比，在最大输出功率条件下，用乳化形式的 LPO 运行的柴油机使 HC 排放增加了 0.1 g/kWh，对于 LPOE4 和 0.15 g/kWh 对于 LPOE2 燃料。将 LPO 重新配方为乳化形式会使 CO 排放比纯 LPO 增加 25-53%。此外，与纯 LPO 和柴油燃料相比，将 LPO 制成乳液会导致较低的气缸压力和放热率。
