生物质热解燃油在柴油机上的应用效果

生物质通过快速热解得到的生物质热解燃油主要成分为含氧有机混合物和水，不宜直接作为燃料使用，但与柴油乳化后可实现其在发动机上的应用。在确定生物质热解燃油/柴油乳化油乳化剂的最佳亲水亲油平衡（HLB）值后，利用超声波乳化装置制备了生物质热解燃油质量分数为10%的乳化油（用BPO10表示），然后在一台未作改动的直喷式柴油机上对燃用BPO10时的燃烧和排放进行了研究。结果表明，生物质热解燃油/柴油乳化油乳化剂的最佳HLB值约为5.8。与0号柴油相比，发动机燃用BPO10时燃烧始点推迟，预混燃烧放热峰值明显升高，扩散燃烧放热峰值略低，最高燃烧压力较低，燃烧持续期缩短；燃用BPO10时有效燃油消耗率较高，而有效热效率与0号柴油的相当；燃用BPO10时可同时大幅降低NOx和碳烟排放，但HC和CO排放升高。

Application of biomass pyrolysis oil to direct injection diesel engine

Biomass pyrolysis oil (BPO) produced through biomass fast pyrolysis process is mainly composed of oxygenated organics and water, thereby restricting its direct use as fuel is essential. However, the use of BPO in diesel engines can be realized by developing emulsions from BPO and diesel fuel. In this paper, the emulsion with 10 wt % BPO in No.0 diesel, represented by BPO10, was produced by using ultrasonic emulsification method after determining the optimum hydrophilic and lipophilic balance (HLB) value of the emulsifier for the emulsions from BPO and diesel. Then, the combustion and emission characteristics of an unmodified direct injection diesel engine operating on BPO10 were studied and compared with those of No.0 diesel operation. The results show that the optimum HLB value of the emulsifier for the emulsions from BPO and diesel is about 5.8. The engine operating on BPO10 exhibits a later combustion start point, displays a higher peak value of premixed burning rate and a slightly lower peak value of diffusion burning rate, and has a lower peak combustion pressure and a shorter combustion duration when compared with No.0 diesel. In addition, the brake specific fuel consumption is higher and the effective thermal efficiency is comparable for BPO10 operation. NOx and smoke emissions with BPO10 were reduced significantly, while HC and CO emissions were increased when compared with those of No.0 diesel operation.