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Production and characterization of biomass fast pyrolysis oil blends for combustion testing as drop-in fuel alternatives in a single cylinder diesel engine

University of British Columbia

This research sought to demonstrate the potential of biodiesel and softwood derived Fast Pyrolysis Oil (FPO) blends as an alternative low-carbon drop-in diesel fuel. FPO was supplied from an in-house fluidized bed reactor as well as a commercial source. Separate FPO-biodiesel blends from both FPO sources were prepared using initial volumetric ratios of 80:20 and 60:40 (biodiesel:FPO, by volume). Upon blending each performed volumetric ratio, mixing and a 24 hour settling period, two layers formed and the top, biodiesel-rich layers containing about 5 and 10 vol % FPO were decanted and characterized on the basis of a thermogravimetric analysis, viscosity, acid number, water content, elemental analysis, and heating value. Significant decreases in viscosity, acidity, and water content from the original FPO validated blending as means of extracting compounds suitable for use as fuels from pyrolytic liquids in biodiesel. A single cylinder, direct injection diesel engine was used to analyze the combustion performance of the FPO fuel blends against neat diesel and biodiesel. Fuel performance was characterized on the basis of a thermodynamic analysis and corresponding exhaust measurements for CO₂, CO, unburned hydrocarbons, particulate matter, and NOx. Two thermodynamic measurement campaigns were performed in order to provide insight into FPO fuel performance across various engine conditions. In addition to the thermodynamic measurements, in-cylinder high-speed photography was implemented to support the interpretation of thermodynamic combustion data. Engine testing revealed similar indicated efficiencies for biodiesel and diesel at all considered engine-operating modes, while blend fuels showed indicated efficiencies between 75 and 95% of diesel values. FPO fuels exhibited increased ignition delays and shorter combustion durations with greater FPO blend concentrations, though this could be partially compensated for using a pilot injection strategy. The longer ignition delays of the blend fuels resulted in overly lean regions of the cylinder, which produced largely premixed combustion events contributing to brake specific CO and uHC emissions up to 1.5 and 3.5 greater than diesel, respectively. Specific PM emissions were 41-62% lower for blend fuels than diesel. Both blends of in-house FPO showed similar PM emission performance, however at higher concentrations than low blend commercial fuel.

Text

2017-01-25

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/60409

Mechanical Engineering

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/