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ZERO WASTE BIODIESEL: USING GLYCERIN AND BIOMASS TO CREATE RENEWABLE ENERGY
Impact/Purpose:
Technical Challenge to Sustainability: With the advent of alternative fuels, biodiesel is becoming extremely popular since vehicle modification is unnecessary. However, the creation of biodiesel from vegetable oil in a transesterification generates a glycerin waste product, which has flooded the market for commercial glycerin in the United States. This waste stream needs to be explored for industrial and personal use as a new energy source.
Innovative Design Approach with Technical Merit to Address the Challenges: Developing an innovative product and process for making a new product from the glycerin waste is our focus. By combining the biodiesel glycerin with waste stream biomass, such as sawdust or used paper, a new product can be formed that is combustible. This product would be valuable because the raw materials are low in cost and the product is fully carbon neutral. We are seeking the means to develop a pilot scale mechanical device to synthesize a solid combustible form of glycerin and biomass for the investigation and evaluation of this waste as an alternative energy source.
Description:
The procedure for the creation of pellets is fairly mundane, however crucial, in order to create a standard and repeatable process. The pellets biomass material are mixed by weight ratio, and blended to a consistent particulate size. The glycerin to biomass ratio by weight is mixed together. The mixture is transferred into the mold and the ends are then pressed by a vice grip or some other agent that can deliver a significant amount of force to form the pellet.
Key observations were made during the process in creating a sample pellet. When combusting a pellet, it is best that the substance has dried to a point where the water content of the object is negligible. This concern arises from two aspects. The first aspect is making sure that the raw materials have a low water content. The second aspect is making sure that the pellets are not exposed to ambient air. Ambient air contains a relatively small amount of moisture but due to glycerin being hydrophilic in nature; i.e. the strong tendency to absorb water over time, the pellets will absorb moisture from the surrounding air. This moisture content could act as a partial heat sink, and thereby limiting the amount of energy available for conversion to electricity.
Experiments were conducted with a calorimeter bomb to obtain the energy content of the glycerin pellets and the results show that the energy content from our waste glycerin pellets are around the low end energy content produced by coal and RDFs. Our results also show that the energy content of the pellets produce roughtly 0.7 kJ per gram more than traditional biomass. We do not see that this will be a major problem considering that with the additive of glycerin the pellets burn roughly 3 times longer than biomass. Our results also show that as the glycerin to biomass ratio increases the energy content increases also which agrees with the theoretically calculated energy contents.
Due to the observations that were observed the most appropriate place for this product to be used is as a substitute for coal in existing energy plants, wastewater treatment plants where RDFs are used, and/or possible home heating unit such as the types that are popular in Europe.