Susan A. Roces

Microwave-Enhanced Alkali Catalyzed Transesterification of Kenaf Seed Oil

A two-step process assisted by microwave irradiation was used to produce kenaf oil methyl ester. The first stage made use of sulfuric acid catalyst to convert free fatty acids into methyl ester, while the second made use of potassium hydroxide catalyst under microwave irradiation to transesterify the triglycerides. The four major experimental variables considered in the latter step were catalyst concentration, alcohol-oil molar ratio, reaction temperature and reaction time. The results were analyzed statistically for the effect of those variable parameters on the reaction conversion. Optimum conversion of about 94% was obtained at the optimum values of variables 0.55% KOH catalyst, 4.5:1 methanol-oil molar ratio, 57.5oC and 6.5 minutes reaction time. The analyses on the biodiesel produced by this method proved to be acceptable in comparison to ASTM biodiesel standard.

Relationship of mechanical properties and temperature of carbon fiber-reinforced plastics under microwave irradiation

One of the problems with the use of carbon fiber-reinforced plastics (CFRP) is the difficulty of recycling or disposing of them. Hence, it is necessary to find processes to treat CFRP wastes faster and more effectively. Because carbon fibers are good microwave absorbers, there is significant potential for the use of microwave irradiation for the processing of CFRP wastes. In this study, the relationship of mechanical properties and radiation temperature during microwave irradiation of unidirectional and cloth-type CFRP were studied. Experimental results indicate that microwave irradiation degrades CFRP’s mechanical properties by breaking down the bond between the polymer matrix and the carbon fibers.

Design and Fabrication of Microwave Pyrolysis System

This paper focuses on the design and fabrication of a microwave system for plastic pyrolysis. The microwave system used is a modified domestic microwave oven with a maximum power of 1,000 watt, single feed and 2.45 GHz frequency. Simulation was done to be able to study the field distribution inside the cavity. Distributions of electric field strength (E), dissipated power inside the oven cavity, skin-depth of electromagnetic waves in charcoal media, and mode generation were investigated to determine the dimension of the reactor and the best position for the reactor to be placed inside the cavity in order to get better heating generation. It was found that the dissipated power for the whole cavity was uneven. Skin-depth should be from 19.2 to 19.657 mm. The reactor should be of a diameter less than 19.2 mm and placed in the high-power density regions inside the cavity. A preliminary study was carried out using polypropylene (PP), Low-Density Polyethylene (LDPE) resins and charcoal as microwave absorber at 460-510degC