16th International Conference
on Microwave and High Frequency Heating

18-21 September 2017, Delft, The Netherlands
14:30   Microwave assisted chemistry and processing (3)
Chair: Dariusz Bogdal
14:30
15 mins
THE OXIDATIVE DEHYDROGENATION OF ETHANE: CONVECTIONAL VS MICROWAVE HEATING OF CATALYSTS
Vasiliy Bolotov, Vladimir Chesnokov, Yuriy Tanashev, Valentin Parmon
Abstract: The oxidative dehydrogenation of ethane (ODE) to produce ethylene is an attractive alternative for petrochemical industry. Compared with a steam cracking, catalytic cracking and catalytic dehydrogenation, ODE is thermodynamically favored, and can be performed at lower reaction temperature without formation of coke. The main problem of ODE is usually a moderate selectivity of respective catalysts due to high reactivity of ethylene formed at high reaction temperature (> 600 °C). To increase selectivity of ODE, parallel and consecutive deep oxidation of ethylene performed via a homogeneous mechanism should be inhibited (quenched). The selective microwave (MW) heating of a catalyst as compared with a conventional heating allows the creation of conditions where a temperature gradient between “hot” catalyst and “cold” reactor volume is considerable. It is supposed that application of MW can perform effective quenching of the target ODE product. This paper presents the results of high temperature ODE under conventional and MW heating of the catalyst BaCl2 – TiO2 – SnO2. It was found that the MW heating of catalyst results in a decrease of the selectivity of CO and CO2 formation and increase of the ethylene selectivity. The present research demonstrates the capability of MW heating for enhancement of selectivity of ODE.
14:45
15 mins
CHEMICAL COMPOSITION AND ANTIOXIDANT ACTIVITY ASSESSMENT OF ROSE OIL EXTRACTED FROM PETALS USING SYNERGETIC MICROWAVE & ULTRASOUND ENERGY
Mariana Patrascu, Marilena Radoiu
Abstract: The synergetic effect of microwave and ultrasound treatment on the chemical composition and antioxidant activity of rose essential oil was studied. The rose essential oil was extracted from fresh Rosa x damascena Mill. petals by four methods: hydrodistillation, steam distillation, organic solvent extraction, and ultrasounds followed by microwave hydrodistillation. The chemical composition of the extracts was analysed by GC-MS, and the antioxidant capacity by DPPH. It was found that both chemical composition and the antioxidant activity of the extracts depend on the extraction method. Overall it was found that microwaves coupled with ultrasonic treatment can be used effectively for the intensification of the extraction of monoterpenes and sesquiterpenes - fragrance bearing molecules - and equally, for increased antioxidant activity while using about 4 time shorter extraction time.
15:00
15 mins
GREEN EXTRACTION USING MICROWAVE AND CENTRIFUGAL FORCE
Alice Angoy, Pascal Ginisty, Marc Valat, Farid Chemat, Pascale Goupy, Catherine Veyrat, Pierre-Nicolas Parent
Abstract: In many industrial processes, liquid/solid separation is achieved by a combination of mechanical and thermal (drying) processes, resulting in in a low final water (or solvent) content in the product. Thermal drying in a mechanical separation device offers a lot of advantages (lower investment, higher productivity, limited footprint...). Moreover, coupling mechanical and thermal effects may lead in some cases to synergic effects allowing an optimal use of energy. Thermal input by dielectric heating may be adapted to a centrifuge. Previous work (Xabier Apaolaza 2014)1 allowed to develop a centrifugation pilot allowing the implantation of microwaves. First experiments have been conducted on lettuce for extraction of phenolic compounds. Extraction efficiency has been evaluated as a function of rotational speed and power of microwave. The results show the influence of superimposition of dielectric heating and centrifugal force on extraction. This new process could be used for extraction in the field of food ingredients industry, cosmetics, pharmacy and food supplements. This pilot will be multifunctional and adapted to different extraction methods, either by distillation for obtaining essential oils and flavors, gravity for obtaining fluid extracts, or by food-sourced solvent such as vegetable oils to obtain extracts rich in bioactive compounds. The proposal for a mechanical / thermal coupling in the field of green extraction appears to be a real innovation and could allow a high yield extraction to obtain products with high added value.
15:15
15 mins
HIGH TEMPERATURE DIELECTRIC PROPERTY MEASUREMENT SYSTEM AND METALLURGICAL MATERIALS DIELECTRIC PROPERTY DATABASE
Chenhui Liu, Jinhui Peng, Libo Zhang
Abstract: Dielectric properties of metallurgical mineral powders varies with temperature and chemical composition is important for design microwave industrial equipment and process optimization. The cylindrical resonant cavity perturbation method in this work was designed by the Microwave Properties Testing System in Kun Ming University of Science and Technology. During experiments, the sample was placed in a cylindrical resonant cavity (TM0n0). The inner dimensions of the cavity are 1.9 cm height and 20 cm diameter, respectively. The scattering parameters of samples were measured by a vector network analyzer (E5071C Agilent). High temperature was obtained by an eddy current heating system placed inside the holder cavity. Each sample is employed and uniformly compacted into a quartz tube (inner dimensions 4.1 mm, height 52 mm). The permittivity measurement experiments were carried out from room temperature to 1400℃ with microwave frequency 2450 MHz under air atmosphere. The testing range is permittivity r : 2 to 100, loss tangent tan: 5  10-3~2. The test error: room temperature: |/|2.0%,|tan| 10% tan +310-3; high temperature:| /|  4.5%,|tan|15%tan+ 510-3. We set up a metallurgical materials database contain 300 kinds of mineral materials.