Ignition and combustion characteristics of hydrotreated pyrolysis oil in a combustion research unit

Abstract

Biomass-derived fuels are promising in reducing life-cycle CO2 emissions and achieving the goal of sustainable mobility in the future. This work investigates the ignition behavior and combustion process of hydrotreated pyrolysis oil (HPO) derived from various biomass resources. They are tested in a combustion research unit based on constant volume combustion technology, which imitates the ignition behavior in compression ignition engines. Various conditions are tested and HPO are benchmarked with commericially avalable biofuels and fossile fuels: hydrotreated vegetable oil (HVO) and fatty acid methyl ester (FAME), diesel, and marine gas oil. The results showed that the igntiion delay time follows an order of folloing: HPO > diesel-like fuels > HVO. Both the biomass type and after-treatment have a small influence on the ignition delay of HPO. Two combustion regimes are observed at different chamber temperature range. It also revealed that blending HPO into HVO can extend the ignition delay of HVO. And ignition delay of HVO/HPO increases as the HPO blend ratio increases. At 75 vol% HPO blend ratio, the HPO/HVO blend shows identical ignition and combustion behavior as diesel. In addition, the viscosity of HPO/HVO blends and diesel are also quite similar. The results indicated the possibility of using 100% bio-fuel in a modern marine engine to provide power to future mobility.