Performance and emission charactertistics of an IDI diesel generator fueled with wood pyrolysis oil-butanol blended fuels

Wood pyrolysis oil (WPO) derived from wood has been regarded as an alternative fuel to be used in diesel engines. However, direct use of WPO in a diesel engine is not possible due to the low energy density, high acidity, high viscosity, high water content and low cetane number of WPO. The most widely used approach to improve the fuel qualities of WPO are blending of WPO with other hydrocarbon fuels which have higher cetane number. Generally, WPO and fossil fuels are not usually blended because of its different polarity; a cumbersome process called emulsification is needed to mix WPO and fossil fuels with appropriate surfactants. However, the emulsification process needs additional time and costs, and clogging and polymerization problems in fuel supply system are still occurred. Polymerization of WPO can be prevented by diluting WPO in alcohol fuels. Early mixing with alcohol fuels has an added benefit of significantly improving the storage and handling properties of WPO. WPO-alcohol blended fuel still does not produce the self-ignition; hence additional cetane enhancements should be added in the blended fuel. In this study, we would like to use WPO through the blending with n-butanol and cetane enhancements (PEG 400 and 2-EHN). Experimental results showed that highly stable engine operation was obtained for WPO-blended fuels with a maximum WPO content of 20 wt%. The combustion of WPO-butanol blended fuels produced slightly higher hydrocarbon (HC) and carbon monoxide (CO) emissions than diesel combustion due to the incomplete combustion of the blended fuels. And nitrogen oxides (NOx) emissions for the blended fuel were higher than those of diesel due to the high oxygen content of the blended fuels. PM generation from the blended fuels was almost zero due to the high oxygen content of the WPO and n-butanol.