(555b) Evaluation of Reaction Conversion and Energy Consumption During Biodiesel Production Using a Pilot Scale High Shear Mixer Reactor

Biodiesel is a renewable fuel that has the potential to lower vehicle sulfur emissions when used directly or in a blended form, and can be synthesized from fat and oil sources. These sources include refined vegetable oil, crude vegetable oil, waste oil, and animal fat. The two main reaction routes in the production of biodiesel are the esterification of free fatty acids in oil and the transesterification of triglycerides. In each of these routes, several processing stages are employed depending on the purity of the oil. For instance, crude soy bean oil goes through pre-processing stages such as degumming, neutralization, and bleaching prior to transesterification, glycerine removal, and final purification. The pre-processing steps are omitted however, when high purity soy bean oil is used as feedstock.

Although using refined oil is the preferred route, the increased demand for this type of feedstock has resulted in high prices which have encouraged biodiesel manufacturers and researchers to find alternative oil sources. In addition to the search for alternative sources, more research is being conducted to evaluate other biodiesel processing methods and technologies. Both issues are discussed in the current study. First, soy bean oil was processed by two different biodiesel production methods which compared a pilot scale high shear mixer reactor to a stirred batch reactor. The shear mixer was made up of three pairs of fine rotor and stator sets that were more effective in converting triglycerides into methyl esters. Results from this study suggested that a high shear mixer gave higher conversions for shorter reaction times.

Previous experiments comparing a batch reactor to a high shear mixer were conducted such that the amounts of methanol and catalyst added were at 6 moles of methanol and 0.5 wt% sodium methoxide catalyst respectively, based on the added oil. The next set of experiments will evaluate the reaction conversions by increasing and then lowering either the amounts of methanol or catalyst. In addition, the energy consumption of the high shear mixer will be evaluated and then compared to that of the batch system.

High purity soy bean oil was previously tested. Now a pre-processed waste oil sample with a %FFA below 0.4wt % will be tested and its results compared to that of soy bean oil. After looking at the short reaction times of the high shear mixer, the next phase will be to evaluate reaction conversion of refined soy bean oil as compared to that of pre-processed waste oil.