DEVELOPMENT OF MICROWAVE SPECTROSCOPIC RESONANT SENSOR FOR APPLICATION IN EDIBLE AND WASTE OIL VERIFICATION
ABSTRACT This work is a contribution and value addition to edible oil verification and the waste oil recovery process. It comprised the development of a sensing technique that will primarily enable the ability to probe different oils and establish their differences for authentication, and in addition test free fatty acid levels in waste cooking oils, and methanol levels in the oil recovery process. It does so in real time and in a cost-effective manner. Various techniques that have been applied to this so far, have proven to be either too sophisticated and require specialised trained persons to employ, or are too expensive for large scale implementation. Microwave spectroscopy is used to develop the sensor. Experiments were carried out using samples of different edible oils to probe and verify their differences, as a result each sample presented different signal spectra. To verify the authenticity of extra virgin olive oil diluted with sunflower oil, samples were mixed in different percentages of concentration, 0 to 50% of sunflower in extra virgin olive oil. The results were regressed and attained a value of correlation coefficient of 0.9739. To probe the levels of free fatty acid and methanol in oil, 0 to 17.5% of free fatty acid was mixed with vegetable oil, and the results attained a regression coefficient value of 0.9942. Levels 0 to 17.5% of free fatty acid were mixed with methanol and attained 0.9944. Levels 30 to 50% mixed with methanol gave a value of 0.9846. Using the results of the experiments, computer aided models were evolved, which were simulated using COMSOL Multiphysics software. The simulated work produced results that were favourably comparable to the laboratory experiments. The design of a new conceptual industry model of the microwave spectroscopic resonant sensor for waste oil recovery was carried out and scaled out of the laboratory model. Finally, the industry model with a Q-factor of 7856 and resonant frequency of 2.3562 GHz was attained as a result.
TD Environmental technology. Sanitary engineering
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