Biofuels

Biofuels are alternative transportation fuels that are made from agricultural crops and certain types of trees. In efforts of reducing the consumption non-renewable resources, biofuels have been investigated to be renewable additive or all together replacement for gasoline as a transportation fuel. There are many methods of creating biofuels, one is to use fast pyrolysis with biomass or municipal solid waste (MSW) to produce a viscous bio-oil which can be converted into transportation fuel.

This process has been adopted by the AEE Biofuels team with the goal to increase the overall efficiency and amount of bio-oil produced. Our mission as a part of the Biofuels team is contribute to the research being done in this field and learn more about the process of fast pyrolysis. In order to develop a new, more sustainable technology, much research is being completed on possible alternative energy sources; one of which is the field of biofuels.

The main objective of the Biofuels Team in AEE is to have student members gain knowledge regarding the types of biofuels (gas, liquid, solid) that can be produced from renewable biomass and their means of production. We will focus on conversion of woody biomass (poplar chips) using the pyrolysis pilot plant at the APSRC building near the airport. Students will gain experience in preparing for and conducting the pilot plant runs involving a set of complex unit operations including a fluid bed reactor, two cyclones, two condensers, and an electrostatic precipitator. Products of pyrolysis will be characterized using analytical instruments on campus in room 205 (pH), 311 (gas chromatography-mass spectroscopy), and using the P. Chem lab in Chemistry (bomb calorimetry for heating value). Students will also learn about process safety to identify and mitigate hazards inherent in the process. Students will also learn of methods to evaluate alternative energy for sustainability; economic, environmental, and societal impacts and benefits. One option for the Biofuels Team is to conduct detailed process design and analysis using computer-aided tools such Aspen Plus and SimaPro.

The Biofuels team is working towards optimizing a pilot scale fast pyrolysis plant in order to increase the yield of bio-oil from the reaction. The thermochemical conversion of the biomass produces hot vapors and char which are sent through cyclones, condensers, and an electrostatic precipitator. These unit operations are designed to remove all the solid char leaving the reactor and to condense the vapors for collection. After collecting all condensable vapors, the liquid bio-oil formed can be catalytically upgraded to produce a drop of biofuel for transportation and other engine applications.

Past pilot plant runs have produced a 35 wt% bio-oil yield in comparison to literature which supports a theoretical production of 75 wt% of bio-oil. The overarching goal of our team is to work towards a higher bio-oil yield. Current objectives include improving the heat transfer within the reactor by means of implementing a new heating design in both the gas preheating and reactor sections of our reactor, creating a metal replica in order to observe the effect of having the heater inside the reactor, and running the pilot plant again in order to confirm previous operating condition suggestions of 0.5 kg biomass/hr and a gas flow rate of 9.5 SLPM.