16th International Conference
on Microwave and High Frequency Heating

18-21 September 2017, Delft, The Netherlands
15:45   Industrial, Medical and Biological Applications
Chair: Erik Esveld
15 mins
Luiz Alberto Jermolovicius, Eduardo Victor dos Santos Pouzada, Renata Borges do Nascimento, Edmilson Renato de Castro, José Thomaz Senise, Bárbara Bertin Mente, Mônica Caroline Martins, Suzana Mayumi Yamaguchi, Viviane Ciola Sanchez
Abstract: There are two families of chemical processes for ethylene production: (1) the petrochemicals whose raw materials are nafta or refinery gas, and (2) the alcohol chemical based on ethanol dehydration. The ethylene from ethanol is called ‘green ethylene’, because it is produced from renewable raw material. Although known as ‘green’, ethanol dehydration is a pollutant process because it uses fossil fuel to heat the dehydration reactor producing carbon dioxide, a greenhouse effect gas. This paper presents a new way for green ethylene production: a microwave-assisted process. It is based on the catalytic system using the ZSM-5 zeolite doped with manganese and zinc kept in a ceramic matrix susceptible to microwave heating within a continuous tubular reactor. Exploratory tests results showed: a) an effective operation of that produced ethylene with 60.8% product yield on stoichiometric base. This figure is higher than the usual 58% obtained from petrochemical cracking units and of the same order from ordinary dehydration; b) a more rational use of the energy applied to the reactor of dehydration, because only the catalytic bed was heated due to the selective microwave heating; c) an ecological advantage because of the suppression of greenhouse gas generation.
15 mins
Birgitta Wäppling Raaholt
Abstract: A pilot-scale process for continuous in-flow microwave processing of particulate pumpable foods, designed and implemented at RISE Research Institute of Sweden [1], was studied for heat treatment of a particulate, viscous model food at high temperature conditions at 2450 MHz. In this paper, the technology will be discussed as an alternative high-temperature short-time (HTST) processing method for a high-concentrated particulate model product. The technology combines TM020 and TM120 microwave mode heating. The rapidness in heating the product will be illustrated for selected time-temperature conditions after tubular microwave heating. The latter corresponds to the required microbiological inactivation, for a product intended for storage at ambient conditions or cool storage, respectively. As will be exemplified, the microwave HTST system studied results in large process flexibility. Additionally, it offers advantages in product quality.
15 mins
Ali Akman, Hasan Hüseyin Engin, Ali Oktay
Abstract: In this paper, the microwave energy assisted drying of the fine sand has been investigated and in particular it has been focused to find the experimental conditions which can be used to accelerate the conventional drying phenomenon in order to save energy in the industrial processes. The main mechanism is effectually heat and mass transfer in a perfect porous material being under a microwave power radiation. In order to obtain the thermal and kinetic(moisture) evaluation, the experimental and numerical works have been carried out on the fine sand using an experimental apparatus operating at the mode TE01 and the frequency f=915MHz. The results are obtained in taking into account the dielectric properties of the material in function of the moisture content and the temperature. These works have been point out important kinetic and thermal aspects allowing a better understanding of the microwave pre-heating assisted drying process of a porous material. The influence of moisture content and the temperature evolution on the vapour diffusion and also capillary flow during the microwave radiation are importantly carried out. The phenomenon generating a pressure gradient inside the material, which is the important force for the moisture transport both as liquid and vapour, can be an important property which will be undertaken in order to reduce the energy consumption of the whole drying process. As it is known commonly for many materials, the microwave assisted drying of the fine sand comprises three stages: an incubation period, whereby a rapid increase in temperature occurs, a constant-rate drying period, during which a rapid moisture rate occurs at about 100ºC, and a falling-rate drying period, during which a significant increase in temperature is observed again. It was observed that the quasi totally of the microwave energy is absorbed by the material. The water in the material absorbs microwave energy intensively during the incubation period, during which the moisture content is relatively constant and consequently the generated thermal energy, so the consumpted energy, mainly elevated the temperature of the material. It was found that the average temperature is increased rapidly to 90ºC within 3 min. at the center of the material and it’s corresponded an average heating rate about 25ºC/min. In our work, we study the drying process of the fine sand which is affected firstly by the microwave heating in the incubation period, here heated to about 90ºC, and then followed to an hot air drying. The experimental and numerical results in this study, as well as the thermal and kinetics analyses, could contribute to the better understanding of drying mechanism for the fine sand, as well as in the process of making the industrial design of microwave drying more efficient by reducing the inefficient drying period and the energy consumption.
15 mins
David Mclean, Joel Mclean
Abstract: The prevention of unnecessary suffering at slaughter is considered to be an imperative, the majority of slaughtered animals are stunned prior to slaughter by mechanical, electrical or gas inhalation means. However, the Jewish and Muslim communities require that any such stun is fully reversible in order to meet the requirements of their religious laws. This paper describes the research and development trials undertaken during the commercialisation stages of the reversible microwave stunning project. Electromagnetic energy is used to induce a rise in temperature in the brain, by 7-8°C, to a point at which the animal loses consciousness, and electroencephalogram (EEG) patterns indicative of insensibility have been demonstrated. A brief literature review on the current state of microwave stunning is presented including results from various phases of experimental work involving microwave trials at 922MHz on live cattle. The commercial configuration required a flexible and small footprint applicator interface with the animals head. The development of such was based around coaxial and dielectric wave guide technology.
15 mins
Andreas Rosin, Michael Hader, Udo Gaipl, Benjamin Frey, Stephan Gekle
Abstract: Hyperthermia, the selective heating of tumor tissue to temperatures between 39 and 46 °C, gets into focus as an addition to the existing oncological treatment strategies due to technological progress and positive outcomes in clinical studies. Nevertheless, exact mechanisms of tumor cell inactivation under microwave radiation are not fully understood yet. In this study, experimental (biologic/immunologic-medical) and process engineering methods are combined with numerical process and molecular dynamic simulations. Thermal inactivation experiments were performed ex vivo with B16 melanoma cells and MCF-7 breast cancer cells in a self-designed closed loop reactor. Besides microwave radiation at 2.45 GHz at continuous or pulsed mode conventional warm-water heating was used for comparison. To distinguish viable from dead cells, AnnexinV staining method was used and supported by FE SEM imaging (Fig. 1). In addition, numerical simulations were done to identify differences between both heating methods and temperature profiles. Results indicate a lowering of temperature threshold for cell inactivation by approximately -2 K under microwave radiation, which will be discussed.