The applicability of catalytic esterified biomass-pyrolysis-oil surrogates in diesel engine

Catalytic esterified biomass-pyrolysis-oil is a potential renewable fuel for application in internal combustion engine. Although a number of studies have been conducted on bio-oil production and upgrading, relatively few attention has been paid on the bio-oil application in diesel engine. Here, the aim of this paper is to investigate the performance and emission characteristic of EF (ethyl formate), EA (ethyl acetate), EP (ethyl propionate) in diesel engine. For this purpose, 10% and 20% vol. of the selected ester surrogates were blended with diesel and tested in a diesel engine to check the variation of BSEC (brake specific energy consumption), emission temperature, CO emission, NOx emission and soot opacity along with the increase of load (or power output), and the influence of ester additives on soot morphology was also inspected with a Fourier transform infrared spectroscopy (FTIR) and a field emission scanning electron microscopy (TEM). In the test, EA and EP blended fuels had lower CO, NOx, and soot emissions than diesel, meanwhile, EF blend had the lowest NOx, emission but the highest soot opacity among the test four fuels. In addition, the added esters reduced the density of the chemical bonds in soot, and effectively inhibited the formation of crystal structure of soot. The results indicate that EA and EP blended fuels have a better operation and emission performance than diesel. This work reveals that it is possible to operate diesel engine with catalytic esterified biomass-pyrolysis-oil.