Application of biomass fast pyrolysis part II: The effects that bio-pyrolysis oil has on the performance of diesel engines

This study used the fast pyrolysis method to produce bio-oil from coffee bean residue. The oil was mixed with diesel fuel through emulsification to produce emulsified fuel with varying proportions. A singlecylinder diesel engine connected to a 12-kW power generation system was used as the test system to examine the performance indices of a diesel engine under various loads and rotational speeds when using three fuel mixtures with varying proportions of bio-oil (i.e., CPO (coffee bean residue pyrolysis oil) 0 (100% diesel), CPO 5 (5 vol.% bio-oil/95 vol.% diesel), and CPO 10 (10 vol.% bio-oil/90 vol.% diesel)). According to the results, compared to CPO 0, the addition of CPO 5 and CPO 10 increased the fuel consumed for the same power output. Although CPO 5 and CPO 10 had lower heating values that reduced combustion efficiency, the water content and emulsification properties of these fuels enhanced certain aspects of combustion. Increasing the proportion of bio-oil effectively reduced NOx emissions, but in certain situations, denser smoke was produced. The smoke resulted from the added bio-oil, which reduced heating values and combustion efficiency. The emulsification properties of the oil contributed to microexplosion of oil droplets, which enhanced combustion characteristics. Crown Copyright (C) 2013 Published by Elsevier Ltd. All rights reserved.