Impact of methanol alternative fuel on oxidation reactivity of soot emissions from a modern CI engine. (15th May 2020)

• Record Type: Journal Article
• Authors: Wei, Jiangjun; Fan, Chenyang; Qiu, Liang; Qian, Yejian; Wang, Chenfang; Teng, Qin; Pan, Mingzhang
• Is Part Of: Fuel. Volume 268(2020)
• Publication Date: 2020-05-15
• Subjects: Methanol blend -- Oxidative reactivity -- Soot structure -- Soot chemistry -- CI engine; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2020.117352
• Languages: English
• ISSNs: 0016-2361

Abstract

Graphical abstract: Highlights: Soot reactivity of diesel engine fueled with methanol-diesel blends was investigated. Methanol addition leads to a higher oxidative reactivity of diesel soot. Effects of methanol addition on soot structure and chemistry were assessed. Methanol blend yields soot with less compactness and more disordered structure. Methanol addition increases content of aliphatic C-H groups on diesel-soot surface. Abstract: This paper compared the soot reactivity and its primarily related factors including soot structure, graphitization degree and surface functional groups, when using mineral diesel fuel (DF) and methanol blended fuel (MBF) at two typical low and high engine loads. Results showed that the soot reactivity increases with increasing methanol concentration in the MBF. Additionally, with the constant methanol blend ratio of methanol, the reactivity of MBF soot degrades as the engine load increases. Correspondingly, the MBF soots had lower aggregate compactness, smaller primary particle size, more disordered structure and more active aliphatic C-H groups in comparison with the DF soot, providing higher concentration and accessibility of active sites for oxidation reactions. The addition of methanol creates variations in combustion kinetics and fuel formulation, which exerts reverse effects on the soot structure and chemistry. Therefore, the factors related to these properties show non-monotonic variations when alter the methanol blend ratio and engine operating mode. Especially, when the methanol blend ratio increases from 10% to 15%, the soot structure and chemistry transform onto the features that are reluctant for soot oxidation.