Heat-Modeling of Microwave Assisted Epoxidation of Palm Acid Oil

Abstract

<b>Problem statement:</b> While microwave chemistry could well be the most convenient, rapid&#13; and energy-saving way to initiate a chemical reaction, the issues of thermal versus microwave specific&#13; effect remain unaddressed. <b>Approach:</b> A three-dimensional Finite Element Model (FEM) was developed&#13; to predict temperature profile during the enzymatic epoxidation of palm acid oil using microwave&#13; heating. Three-dimensional partial differential equations are formulated for the electromagnetic field and&#13; heat and mass transfer processes. The temperature profile of the FEM generated from the commercial&#13; software (ANSYS Emag) was verified using experimental data from microwave oven heated samples&#13; containing palm acid oil and reactants in cylindrical bottles and has compared favorably with real time&#13; data. An Infra Red thermometer was used to measure temperature of the reactants during the real time&#13; experiment to ensure less contact with the reaction vessel.<b> Results:</b> Apart from ascertaining the&#13; temperature profile of the epoxidation process in the cylindrical bottle, the heat-modeling of this reaction&#13; can predict the Energy required during the reaction and provide insights to non-thermal microwave&#13; effects. It has shown the possibility of Microwave Non-Thermal Effects and Microwave Selectivity in&#13; Substrate Specificity. The energy used by the microwave irradiated reaction is by far much lesser than the&#13; energy used in conventional heating. This study has also improved the epoxidation process of Palm Acid&#13; Oil by incorporating enzyme as a catalyst and using microwave heating. Epoxidation can be done rapidly&#13; and at a lower level of activation energy of 27.767 kJ mol^&#8722;1. It is a green process with increased&#13; efficiency as it reduced a typically 5-hour reaction to less than an hour. <b>Conclusion:</b> In this study, a&#13; quantitative view of a microwave assisted process of enzymatic epoxidation has been established. We&#13; have successfully developed and experimentally validated a 3D electromagnetic heat transfer model. This&#13; model can thus be used to predict the energy of the epoxidation and other future microwave reactions. the&#13; study also have shown the existence of microwave non-thermal effects and microwave selectivity in&#13; substrate specificity

Microwave-Assisted Alkaline Pretreatment and Microwave Assisted Enzymatic Saccharification of Oil Palm Empty Fruit Bunch Fiber for Enhanced Fermentable Sugar Yield

“…This provides the molecule collision under microwave irradiation extra driving force, which results in higher rate of reaction under microwave irradiation as long as the enzyme is not deactivated by microwave. Under low power level of microwave irradiation, the active site of the enzyme molecules may undergo conformational changes and the microwave energy can modulate the configuration of enzyme molecules by accelerating the molecular rotation, which can provide more chance to make the substrates fit to the enzyme per unit of time [33,57,60]. Another aspect to note is that the amount of enzyme required to achieve maximum yield was also less for the case of microwave assisted hydrolysis.…”

“…Nonthermal effects or microwave effect has been observed in a number of microwave assisted catalytic or enzymatic reactions [33,57]. It has been proposed that at low power level of microwave irradiation, the significant contributor is the non-thermal effects, while the thermal effect plays only a minor role.…”

Microwave Assisted Bioethanol Production from Sago Starch by Co-Culturing of Ragi Tapai and Saccharomyces Cerevisiae

“…This will enhance the efficiency of the enzyme. Non-thermal effects or microwave effect has been observed in a number of microwave assisted catalytic or enzymatic reactions (La Hoz et al, 2007;Yadav and Lathi, 2007;Saifuddin et al, 2011). Previous study on ethanol production from fresh cassava mash also showed that high viscosity caused resistance to solid-liquid separation and lower fermentation efficiency (Srikanta et al, 1992).…”

“…This provides the molecule collision under microwave irradiation extra driving force compared to that under conventional heating, which results in higher rate of reaction under mmicrowave irradiation as long as the enzyme is not deactivated by microwave. The other contribution of the non-thermal effects is that microwave energy can also modulate the configuration of enzyme molecules by accelerating the molecular rotation and electron spin oscillation of the active site of the enzyme, which can provide more chance to make the substrates fit to the enzyme in unit of time (Saifuddin et al, 2011). The specific nature of this enzyme increases yield tremendously.…”

Microwave Assisted Alkaline Pretreatment and Microwave Assisted Enzymatic Hydrolysis of Palm Oil Mill Effluent (POME) for Optimum Fermentable Sugar Yield

“…Non-thermal effects or microwave effect has been observed in a number of microwave assisted catalytic or enzymatic reactions 44 . It has been proposed that at low power level of microwave irradiation, the significant contributor is the non-thermal effects, while the thermal effect plays only a minor role.…”