Experimental study on fast pyrolysis oil blends and its primary kinetics of catalytic conversion
The increasing use of fossil fuels is causing concerns because of the large amounts of carbon dioxide released to the atmosphere and the limited availability in the future. Fuels produced from renewable resources, such as wood biomass, sugars, and vegetable oils, are attracting growing interest because their effect on the atmosphere is more carbon-neutral.
Fast pyrolysis oil is a promising renewable fuel produced from biomass. Products from the pyrolysis reaction are liquids, solids and non-condensable gases. All the reaction products have potential as fuels, in particular the liquid fuels. A lot of research and development have been done on the pyrolysis process and products over the last decades.
Several problems arise when existing equipment is applied for the combustion of pyrolysis oil. Equipment designed for fossil fuels has to be modified in order to maintain stable and continuous operation on fast pyrolysis oil. Water content and oxygenated compounds in the fast pyrolysis oil are the main components which attribute to the differences in fuel characteristics compared to fossil fuels. The effect of these compounds is a relatively low calorific value, low pH value, aging and poor ignition properties. In addition to these properties the viscosity of pyrolysis oil is higher than for conventional fuels.
In order to overcome the aforementioned challenges in combustion of fast pyrolysis oil in a gas turbine the pyrolysis oils must be modified to meet the gas turbine fuel specifications. This study focuses on the upgrading of pyrolysis oil fuel by blending pyrolysis oil with alcohols and (bio)diesels. The second part of the study focuses on catalytic conversion of biomass to pyrolysis oil by.
Fast pyrolysis oil cannot be blended with diesel directly. due to the polar nature of pyrolysis oil, which is not miscible with non-polar diesel fuel. Alcohol can act as a binding agent between the two fuels. The phase stability and fuel properties of the blends are investigated. It was found that diesel and pyrolysis oil could only be blended into a homogeneous phase with large amounts of alcohol, generally at least 60 % of the total mass of the blend. A promising solution could be upgrading the fuel quality of the pyrolysis oil itself by producing it with a catalyst. The effect of the catalyst addition on the primary kinetics of fast pyrolysis and product distribution is investigated successfully in an experimental cyclonic reactor.