College of Engineering

Preliminary Evaluation of Biodiesel from Canarium ovatum (Pili) Pulp Oil and Psophocarpus tetragonolobus (Winged bean) Seed Oil

(7 F U/C/S 1 05)

Dr. Luis Razon
Chemical Engineering Department

Biodiesel or fatty acid methyl esters (FAME) derived from triglycerides of vegetable or animal origin has become very attractive because it is biodegradable, it comes from a renewable resource, it is frequently nontoxic and has been commonly accepted to be carbon-neutral. It is easy to manufacture and requires only small changes in the fuel distribution infrastructure as compared to the changes required if alternatives such as hydrogen were pursued. However, some concerns remain about the cost and availability of feedstocks. The paper presents preliminary studies conducted on biodiesel derived from two novel sources of oil: the fruit pulp of Canarium ovatum (pili) and the seed of Psophocarpus tetragonolobus (winged bean). Oils were extracted using hexane and converted to fatty acid methyl esters. To convert the oils to FAME, a combination of acid-catalyzed esterification and base-catalyzed transesterification was found to be necessary after the oils were found to have a free fatty acid content greater than 0.5%. The resulting FAME were found to comply with selected parts of the biodiesel standards (ASTM D6751-02, EN14214 and PNS2020:2003) except for the kinematic viscosity of the FAME from sigarilyas which was above the maximum limit for the Philippine standard, PNS2020:2003. The study has presented initial results, which indicate that acceptable FAME may be obtained from these two new potential sources of feedstocks. This gives more alternatives to those who want to explore commercial exploitation.

biofuel sample

Commercialization of Acidic Geothermal Wells by pH Buffering

[05 RP (URCO) 1 SY 2002-2003]

Dr. Yolanda Brondial
Chemical Engineering Department

The Philippines being part of the "Pacific Ring of Fire" has abundant geothermal energy. However, since a substantial number of drilled wells produced acidic geofluid with high enthalpy and high wellhead pressure, it becomes imperative to research and develop methods/techniques to be able to use these wells for power generation.

A potential pH buffering method for commercializing high-enthalpy acidic geothermal wells was explored in this study to raise the pH of the geofluids to greater than 3.5, a level considered by geothermal reservoir engineers to be non-corrosive to low-carbon steel. The pH buffering was modeled using statistical software with five design factors (pH geofluid, pH buffer, volume buffer, concentration buffer and temperature of solution), and one response factor (pH of resulting solution). The buffer used was β-chloropropionic acid-Sodium β-chloropropionate (BCPH-NaBCP). Experiments were conducted according to two different experimental designs with the second using the range of values found more effective from the first design. Experimental laboratory results showed that BCPH-NaBCP could raise the pH to > 3.5 for the first design and equal or greater than 4 for the second design and that the initial pH of geofluid, the pH, concentration and volume of BCPH-NaBCP solution significantly influenced the pH of the final solution. In both designs, the temperature of the solution did not show any significant effect on the buffered pH. It was also found out that for a closer range of conentration as in the second design, there was no significant change in the buffered pH. The best combination of factors in the first design was then used in a bench-scale set-up to investigate the possibility of applying pH buffering at high velocity. Results showed that BCPH-NaBCP was useful for fast buffering and could be used to commercialize acidic wells.

Thermodynamic Analysis of Integration Options to Improve the Net Energy Balance of Biofuel Production

(Paper: A Fuzzy Linear Programming Extension of the General Matrix-based Life Cycle Model)

(12 F U/C 3 06)

Dr. Alvin Culaba
Mechanical Engineering Department

Dr. Raymond Tan
Chemical Engineering Department

fuzzy logic

A fuzzy linear programming extension of the general life cycle model is described. The model is suitable for applications involving system design and optimization wherein fuzzy target levels for environmental flows or impacts are specified, and wherein multiple technological alternatives capable of providing equivalent products or services are present within the life cycle boundaries. Solving the model results in an optimal mix of technologies that embodies the best compromise of the fuzzy environmental targets specified. The model formulation is concise and consistent with the generalized matrix-based LCA model; its linearity also makes identification of the optimal solution straightforward. Applications of the model to two illustrative case studies are also given.