Pub Date : 2019-10-15DOI: 10.4995/ampere2019.2019.9832
M. Bobrov, M. Hrebtov, A. Rebrov
Supersonic gas flows activated by microwave discharge are commonly used to obtain thrust for spacecraft. When using a mixture of hydrocarbons and hydrogen as a working gas, the proposed method generates high-speed plasma streams with a high concentration of radicals, allowing it to be used for efficient deposition of diamond films . To optimize diamond synthesis processes, it is necessary to study the effect of various system parameters (geometrical dimensions, radiation power, pressure and others). This abstract presents a numerical simulation of the formation of high-speed gas flow activated by a microwave discharge. The conjugate problem of hydrodynamics and plasma dynamics was solved in the continuum approximation, taking into account impact ionization and thermal dissociation, due to microwave heating of the gas. The simulations were carried out in an axisymmetric formulation. The region of plasma flow formation was a cylindrical chamber (radius 5 cm, height 7 cm). At this stage, hydrogen was chosen as the working gas. The flow outlet is a hole at the center of the lower boundary with fixed pressure of 2 torr. The gas entered the domain at a constant flow rate of 20 l/min through the openings in side wall along its normal. Such flow rate sustained the mean pressure in the chamber at the level 200 torr. Microwave radiation was injected by a coaxial port located above the plasma chamber. The geometrical dimensions of the resonant chamber were selected in order to form the maximum of the electric field intensity over the gas outflow region (total deposited power 1000W). The distributions of velocity, temperature, and concentrations of all components of the hydrogen plasma were estimated. Optimal characteristics of the system were found to reach a high mole fraction of atomic hydrogen, necessary diamond deposition.
{"title":"Numerical simulation of the activation process of supersonic gas flows by a microwave discharge.","authors":"M. Bobrov, M. Hrebtov, A. Rebrov","doi":"10.4995/ampere2019.2019.9832","DOIUrl":"https://doi.org/10.4995/ampere2019.2019.9832","url":null,"abstract":"Supersonic gas flows activated by microwave discharge are commonly used to obtain thrust for spacecraft. When using a mixture of hydrocarbons and hydrogen as a working gas, the proposed method generates high-speed plasma streams with a high concentration of radicals, allowing it to be used for efficient deposition of diamond films . To optimize diamond synthesis processes, it is necessary to study the effect of various system parameters (geometrical dimensions, radiation power, pressure and others). This abstract presents a numerical simulation of the formation of high-speed gas flow activated by a microwave discharge. The conjugate problem of hydrodynamics and plasma dynamics was solved in the continuum approximation, taking into account impact ionization and thermal dissociation, due to microwave heating of the gas. The simulations were carried out in an axisymmetric formulation. The region of plasma flow formation was a cylindrical chamber (radius 5 cm, height 7 cm). At this stage, hydrogen was chosen as the working gas. The flow outlet is a hole at the center of the lower boundary with fixed pressure of 2 torr. The gas entered the domain at a constant flow rate of 20 l/min through the openings in side wall along its normal. Such flow rate sustained the mean pressure in the chamber at the level 200 torr. Microwave radiation was injected by a coaxial port located above the plasma chamber. The geometrical dimensions of the resonant chamber were selected in order to form the maximum of the electric field intensity over the gas outflow region (total deposited power 1000W). The distributions of velocity, temperature, and concentrations of all components of the hydrogen plasma were estimated. Optimal characteristics of the system were found to reach a high mole fraction of atomic hydrogen, necessary diamond deposition.","PeriodicalId":277158,"journal":{"name":"Proceedings 17th International Conference on Microwave and High Frequency Heating","volume":" 6","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120832170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-10-15DOI: 10.4995/ampere2019.2019.9820
I. Călinescu, A. Vintilă, A. Diacon, M. Vinatoru, A. Galán, S. Velea
Algae are very effective in capturing the sun's energy, carbon dioxide from the atmosphere, and nutrients to turn them into useful substances (carbohydrates, oils, proteins, etc.). Besides the main metabolites, there are also secondary metabolites, such as carotenoids (astaxanthin, β-carotene, lutein, lycopene, and canthaxanthin [1]). Both major and compounds existing in small amounts in algae are useful. Oils and carbohydrates could provide biofuels, proteins can get products with nutritional value and from carotenoids can be prepared food supplements. Obtaining biofuel from algae has not yet proved to be economically viable [2, 3]. A much higher interest might be getting food supplements from algae. To increase their value as ingredients for food supplements, algal oils should have a higher degree of unsaturation (rich in omega 3) and an increased carotenoid content to be an important additional benefit in over all processing of algae. There are studies that refer to the influence of environmental factors on algae composition [2], but the microwave influence on algae growth, especially algal metabolites composition change is very poor studied. In this paper, besides the experiments for the activation of algal growth in discontinuous reactors [4] additional work was conducted in a continuous photobioreactor. The goal was checking not only the growth of microalgae but also their content in polyunsaturated oil and in carotenoids. By microwave-controlled irradiation of the nutrient and algae flux, which is recirculated through the photobioreactor and through a glass reactor located in a TE-type monomod cavity, the lipid content of the algae increased, but only, the modification of the lipid fraction content was significantly increased in the concentration of polyunsaturated acids with 16 and 18 carbon atoms. As far as carotenoids are concerned, the algae nannochloris has a higher carotenoid content over many known vegetables holding carotene or lycopene (carrots or tomatoes). Besides oil increasing microwave treatment produced a significant increase in carotenoid content of algae. They can be extracted together with omega-3-rich algal oil and are the basis of very valuable dietary supplements.
{"title":"GROWTH OF NANNOCHLORIS ALGAE IN THE PRESENCE OF MICROWAVES (CONTINUOUS REACTOR)","authors":"I. Călinescu, A. Vintilă, A. Diacon, M. Vinatoru, A. Galán, S. Velea","doi":"10.4995/ampere2019.2019.9820","DOIUrl":"https://doi.org/10.4995/ampere2019.2019.9820","url":null,"abstract":"Algae are very effective in capturing the sun's energy, carbon dioxide from the atmosphere, and nutrients to turn them into useful substances (carbohydrates, oils, proteins, etc.). Besides the main metabolites, there are also secondary metabolites, such as carotenoids (astaxanthin, β-carotene, lutein, lycopene, and canthaxanthin [1]). Both major and compounds existing in small amounts in algae are useful. Oils and carbohydrates could provide biofuels, proteins can get products with nutritional value and from carotenoids can be prepared food supplements. Obtaining biofuel from algae has not yet proved to be economically viable [2, 3]. A much higher interest might be getting food supplements from algae. To increase their value as ingredients for food supplements, algal oils should have a higher degree of unsaturation (rich in omega 3) and an increased carotenoid content to be an important additional benefit in over all processing of algae. There are studies that refer to the influence of environmental factors on algae composition [2], but the microwave influence on algae growth, especially algal metabolites composition change is very poor studied. In this paper, besides the experiments for the activation of algal growth in discontinuous reactors [4] additional work was conducted in a continuous photobioreactor. The goal was checking not only the growth of microalgae but also their content in polyunsaturated oil and in carotenoids. By microwave-controlled irradiation of the nutrient and algae flux, which is recirculated through the photobioreactor and through a glass reactor located in a TE-type monomod cavity, the lipid content of the algae increased, but only, the modification of the lipid fraction content was significantly increased in the concentration of polyunsaturated acids with 16 and 18 carbon atoms. As far as carotenoids are concerned, the algae nannochloris has a higher carotenoid content over many known vegetables holding carotene or lycopene (carrots or tomatoes). Besides oil increasing microwave treatment produced a significant increase in carotenoid content of algae. They can be extracted together with omega-3-rich algal oil and are the basis of very valuable dietary supplements.","PeriodicalId":277158,"journal":{"name":"Proceedings 17th International Conference on Microwave and High Frequency Heating","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122161907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-10-15DOI: 10.4995/ampere2019.2019.9758
M. Radoiu, S. Splinter, T. Popek
An innovative technology for the continuous extraction of bioactive compounds from a wide range of biological materials has been developed, scaled up and successfully demonstrated at commercially-relevant scales. The technology, known as MAPTM, or “Microwave-Assisted Process”, robustly transfers from laboratory to continuous, industrial scale operation. In wide-ranging trials, MAPTM has comprehensively demonstrated its ability to outperform many KPIs of conventional extraction processes, while offering biomass throughput, product consistency and low operational costs not attainable by other emerging technologies. Radient’s proprietary continuous-flow MAPTM extractor, Figure 1, was designed for continuous processing of up to 200 kg/h of biomass material. Verification of the mechanical integrity of the system was confirmed by flow testing of biomass / solvent slurries. Testing and verification of the efficiency of microwave energy transfer to the extractor cavity was completed at various microwave power settings using flowing water at 870 kg/h. The microwave energy transfer to the system was verified to be >95 % in each case. As an example of performance, continuous flow MAPTM extraction of the antioxidant SDG from flax biomass was performed using 70 % ethanol / water as the solvent at two different conditions: - 75 kg/h flax / 5 L/kg solvent / 15 kW microwave power / extractor residence time 24 min; - 110 kg/h flax / 5 L/kg solvent / 20 kW microwave power / extractor residence time 16 min. The industrial-scale conditions for these runs were determined by extrapolating from optimized conditions previously obtained from batch lab-scale MAPTM experiments. The continuous flow approach eliminates the requirement for having geometric similarity between scales, i.e the equipment shape and dimensions do not have to scale proportionately.
{"title":"CONTINUOUS INDUSTRIAL-SCALE MICROWAVE-ASSISTED EXTRACTION OF HIGH-VALUE INGREDIENTS FROM NATURAL BIOMASS","authors":"M. Radoiu, S. Splinter, T. Popek","doi":"10.4995/ampere2019.2019.9758","DOIUrl":"https://doi.org/10.4995/ampere2019.2019.9758","url":null,"abstract":"An innovative technology for the continuous extraction of bioactive compounds from a wide range of biological materials has been developed, scaled up and successfully demonstrated at commercially-relevant scales. The technology, known as MAPTM, or “Microwave-Assisted Process”, robustly transfers from laboratory to continuous, industrial scale operation. In wide-ranging trials, MAPTM has comprehensively demonstrated its ability to outperform many KPIs of conventional extraction processes, while offering biomass throughput, product consistency and low operational costs not attainable by other emerging technologies. Radient’s proprietary continuous-flow MAPTM extractor, Figure 1, was designed for continuous processing of up to 200 kg/h of biomass material. Verification of the mechanical integrity of the system was confirmed by flow testing of biomass / solvent slurries. Testing and verification of the efficiency of microwave energy transfer to the extractor cavity was completed at various microwave power settings using flowing water at 870 kg/h. The microwave energy transfer to the system was verified to be >95 % in each case. As an example of performance, continuous flow MAPTM extraction of the antioxidant SDG from flax biomass was performed using 70 % ethanol / water as the solvent at two different conditions: - 75 kg/h flax / 5 L/kg solvent / 15 kW microwave power / extractor residence time 24 min; - 110 kg/h flax / 5 L/kg solvent / 20 kW microwave power / extractor residence time 16 min. The industrial-scale conditions for these runs were determined by extrapolating from optimized conditions previously obtained from batch lab-scale MAPTM experiments. The continuous flow approach eliminates the requirement for having geometric similarity between scales, i.e the equipment shape and dimensions do not have to scale proportionately.","PeriodicalId":277158,"journal":{"name":"Proceedings 17th International Conference on Microwave and High Frequency Heating","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128889685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-10-15DOI: 10.4995/ampere2019.2019.9850
R. Sallier, L. Nietner, U. Roland, U. Trommler, M. Kraus, F. Holzer, Christian Hoyer, Detlef Schlayer
For drying building structures [1], dielectric heating using RF energy (in this case 13.56 MHz) is an efficient and fast alternative to conventional heating methods based on heat transfer from the surface to the interior of the masonry. Another innovative application of volumetric RF heating is the chemical-free pest control in wood-based materials [2]. For such applications where the RF systems often are not completely shielded, the propagation or coupling of the electromagnetic wave into wires that are placed inside the field cannot be neglected which represents a certain risk. Depending on the different electromagnetic coupling mechanisms, several interference signals can be generated. In order to protect electrical equipment in the surrounding, these interferences have to be significantly reduced by electrical filters. For this purpose, initially a cost-effective (at least in comparison to standard RF measurement systems) and more robust measuring concept was developed. With the help of this system, the common mode (I_CM) interference could be identified as the dominant part and the differential mode (I_DM) interference as a minor disturbance. Based on the experimental evaluation, a cost-effective filter for the respective disturbance was constructed and successfully tested.
{"title":"LOW-COST MEASUREMENT SYSTEM AND FILTER FOR REDUCTION OF EMC INTERFERENCES IN RADIO-FREQUENCY APPLICATIONS","authors":"R. Sallier, L. Nietner, U. Roland, U. Trommler, M. Kraus, F. Holzer, Christian Hoyer, Detlef Schlayer","doi":"10.4995/ampere2019.2019.9850","DOIUrl":"https://doi.org/10.4995/ampere2019.2019.9850","url":null,"abstract":"For drying building structures [1], dielectric heating using RF energy (in this case 13.56 MHz) is an efficient and fast alternative to conventional heating methods based on heat transfer from the surface to the interior of the masonry. Another innovative application of volumetric RF heating is the chemical-free pest control in wood-based materials [2]. For such applications where the RF systems often are not completely shielded, the propagation or coupling of the electromagnetic wave into wires that are placed inside the field cannot be neglected which represents a certain risk. Depending on the different electromagnetic coupling mechanisms, several interference signals can be generated. In order to protect electrical equipment in the surrounding, these interferences have to be significantly reduced by electrical filters. For this purpose, initially a cost-effective (at least in comparison to standard RF measurement systems) and more robust measuring concept was developed. With the help of this system, the common mode (I_CM) interference could be identified as the dominant part and the differential mode (I_DM) interference as a minor disturbance. Based on the experimental evaluation, a cost-effective filter for the respective disturbance was constructed and successfully tested.","PeriodicalId":277158,"journal":{"name":"Proceedings 17th International Conference on Microwave and High Frequency Heating","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120954616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-10-15DOI: 10.4995/ampere2019.2019.9989
M. Moisan, H. Nowakowska
In contrast to RF produced plasmas, in the case of microwave plasmas the energy from the electromagnetic (EM) field is communicated only to electrons since ions, being a few thousand times much heavier than electrons, cannot respond to the periodic changes in the direction of the E-field of microwaves (typical frequency range 100 MHz-300 GHz) and therefore cannot gain energy in the EM field. The energy of electrons is essentially transferred to heavy particles either through numerous enough collisions during the E-field period (high enough gas pressures) or through electron-cyclotron resonance (pressures below mTorr) sustaining in this way the gas discharge. This had led to introduce the concept of power absorbed per electron qA and power loss on a per electron basis qL [1]. Under steady-state conditions and when the plasma volume (the volume in which plasma particles recombine and, thus, power is lost) is equal to the volume in which power is absorbed from the MW field, we have the power balance qA = qL, which can be shown to be much informative than the usual global power balance. qA is defined as where n is the electron collision frequency for momentum transfer, w, the wave angular frequency, e/me, the electron charge to mass ratio, and , the mean squared value of the EM E-field. The value of qA (absorbed power) is shown to adjust so as to compensate exactly for qL (power losses), which is thus the dominant power parameter; as a result, the intensity of the maintenance E-field sustaining the discharge comes out as an internal parameter, i.e., it is operator-independent, in contrast to what is generally believed whatever the kind of E-field sustained discharges. Other related features are: i) whenever this can be achieved, the smaller the volume in which power is absorbed with respect to the volume in which it is spent, the higher the intensity of the maintenance E-field: this leads to higher atomic (molecular) excitation rates inside than outside the absorption region (such is the case in micro-discharges); ii) an interesting fact as far as understanding RF and MW discharge properties is concerned is that the value of qL decreases with increasing frequency from the RF domain to that of MWs; iii) similarity laws, initially derived with DC discharges, are generalized to include RF and microwave discharges. For example, qA/p as a function of pR (p is gas pressure and R discharge-tube inner radius) replaces advantageously the widely used E/p vs. pR similarity law since qA is more easily measured than E2 and further it avoids considering the latter as an external parameter, etc.; iv) using the power per electron balance, it can be proved that the EM E-field intensity under electron cyclotron resonance (ECR) condition passes through a minimum, not a maximum, contrary to what is generally claimed; v) the E-field intensity under pulsed regime can be maximized under short enough pulse length and long enough off-time in between.
{"title":"GENERATION AND MODELING OF GASEOUS PLASMAS USING MICROWAVE (MW) POWER","authors":"M. Moisan, H. Nowakowska","doi":"10.4995/ampere2019.2019.9989","DOIUrl":"https://doi.org/10.4995/ampere2019.2019.9989","url":null,"abstract":"In contrast to RF produced plasmas, in the case of microwave plasmas the energy from the electromagnetic (EM) field is communicated only to electrons since ions, being a few thousand times much heavier than electrons, cannot respond to the periodic changes in the direction of the E-field of microwaves (typical frequency range 100 MHz-300 GHz) and therefore cannot gain energy in the EM field. The energy of electrons is essentially transferred to heavy particles either through numerous enough collisions during the E-field period (high enough gas pressures) or through electron-cyclotron resonance (pressures below mTorr) sustaining in this way the gas discharge. This had led to introduce the concept of power absorbed per electron qA and power loss on a per electron basis qL [1]. Under steady-state conditions and when the plasma volume (the volume in which plasma particles recombine and, thus, power is lost) is equal to the volume in which power is absorbed from the MW field, we have the power balance qA = qL, which can be shown to be much informative than the usual global power balance. qA is defined as where n is the electron collision frequency for momentum transfer, w, the wave angular frequency, e/me, the electron charge to mass ratio, and , the mean squared value of the EM E-field. The value of qA (absorbed power) is shown to adjust so as to compensate exactly for qL (power losses), which is thus the dominant power parameter; as a result, the intensity of the maintenance E-field sustaining the discharge comes out as an internal parameter, i.e., it is operator-independent, in contrast to what is generally believed whatever the kind of E-field sustained discharges. Other related features are: i) whenever this can be achieved, the smaller the volume in which power is absorbed with respect to the volume in which it is spent, the higher the intensity of the maintenance E-field: this leads to higher atomic (molecular) excitation rates inside than outside the absorption region (such is the case in micro-discharges); ii) an interesting fact as far as understanding RF and MW discharge properties is concerned is that the value of qL decreases with increasing frequency from the RF domain to that of MWs; iii) similarity laws, initially derived with DC discharges, are generalized to include RF and microwave discharges. For example, qA/p as a function of pR (p is gas pressure and R discharge-tube inner radius) replaces advantageously the widely used E/p vs. pR similarity law since qA is more easily measured than E2 and further it avoids considering the latter as an external parameter, etc.; iv) using the power per electron balance, it can be proved that the EM E-field intensity under electron cyclotron resonance (ECR) condition passes through a minimum, not a maximum, contrary to what is generally claimed; v) the E-field intensity under pulsed regime can be maximized under short enough pulse length and long enough off-time in between.","PeriodicalId":277158,"journal":{"name":"Proceedings 17th International Conference on Microwave and High Frequency Heating","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128478550","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-10-15DOI: 10.4995/ampere2019.2019.9839
Megan C. Robinson, Z. Popovic
This paper presents an efficiency study for scalable microwave waste management. When waste with carbon content is subjected to volume power densities on the order of 0.25W/cm3 at GHz frequencies, it converts to solid coke fuel with oil and gas bi-products that can further be processed for fuel, leaving no trace. For an efficient process, a well-controlled uniform RF field should be maintained in a non-uniform and time-variable material. We are developing a 2.45-GHz active microwave cavity with solid-state (GaN) spatially power combined sources for lower volumes, Fig.1. In the energy balance calculations, the input energy into the system consists of the waste chemical energy and the DC electrical energy used to obtain the RF power with an efficiency that can reach 70% for kW power levels. The efficiency of RF power conversion to heat in the waste mass is calculated from full-wave simulations for typical waste mixtures and ranges from 10 to 90% depending on the material and cavity filling. The output energy estimates are collected from various pyrolysis process descriptions, e.g. [1], with the total energy being that of the solid fuel (35MJ/kg) and oil caloric values, e.g. 40MJ/kg for plastics and about 10-15MJ/kg for nonplastics [2]. A byproduct is flue gas which can be converted to Syngas [3]. The total worse-case carbon footprint balance (0.3-3) calculations will be presented. Fig. 1. Block diagram of active microwave cavity for waste to fuel conversion. References D. Czajczyńska, “Potential of pyrolysis processes in the waste management sector,” Thermal Science and Engineering Progress, vol. 3, p. 171. Sept., 2017. J.A. Onwudili, “Composition of products from the pyrolysis of polyethylene and polystyrene in a closed batch reactor: effects of temperature and residence time,” Journal of Analytical and Applied Pyrolysis, vol. 86 p. 293–303. Nov., 2009. S. Chunshan, "Tri-reforming of methane: a novel concept for synthesis of industrially useful synthesis gas with desired H2/CO ratios using CO2 in flue gas of power plants without CO2 separation." Prepr. Pap.-Am. Chem. Soc., Div. Fuel Chem 49, no. 1 (2004): 128.
{"title":"SCALABLE MICROWAVE WASTE-TO-FUEL CONVERSION","authors":"Megan C. Robinson, Z. Popovic","doi":"10.4995/ampere2019.2019.9839","DOIUrl":"https://doi.org/10.4995/ampere2019.2019.9839","url":null,"abstract":"This paper presents an efficiency study for scalable microwave waste management. When waste with carbon content is subjected to volume power densities on the order of 0.25W/cm3 at GHz frequencies, it converts to solid coke fuel with oil and gas bi-products that can further be processed for fuel, leaving no trace. For an efficient process, a well-controlled uniform RF field should be maintained in a non-uniform and time-variable material. We are developing a 2.45-GHz active microwave cavity with solid-state (GaN) spatially power combined sources for lower volumes, Fig.1. In the energy balance calculations, the input energy into the system consists of the waste chemical energy and the DC electrical energy used to obtain the RF power with an efficiency that can reach 70% for kW power levels. The efficiency of RF power conversion to heat in the waste mass is calculated from full-wave simulations for typical waste mixtures and ranges from 10 to 90% depending on the material and cavity filling. The output energy estimates are collected from various pyrolysis process descriptions, e.g. [1], with the total energy being that of the solid fuel (35MJ/kg) and oil caloric values, e.g. 40MJ/kg for plastics and about 10-15MJ/kg for nonplastics [2]. A byproduct is flue gas which can be converted to Syngas [3]. The total worse-case carbon footprint balance (0.3-3) calculations will be presented. Fig. 1. Block diagram of active microwave cavity for waste to fuel conversion. References D. Czajczyńska, “Potential of pyrolysis processes in the waste management sector,” Thermal Science and Engineering Progress, vol. 3, p. 171. Sept., 2017. J.A. Onwudili, “Composition of products from the pyrolysis of polyethylene and polystyrene in a closed batch reactor: effects of temperature and residence time,” Journal of Analytical and Applied Pyrolysis, vol. 86 p. 293–303. Nov., 2009. S. Chunshan, \"Tri-reforming of methane: a novel concept for synthesis of industrially useful synthesis gas with desired H2/CO ratios using CO2 in flue gas of power plants without CO2 separation.\" Prepr. Pap.-Am. Chem. Soc., Div. Fuel Chem 49, no. 1 (2004): 128.","PeriodicalId":277158,"journal":{"name":"Proceedings 17th International Conference on Microwave and High Frequency Heating","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134351470","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-10-15DOI: 10.4995/ampere2019.2019.9911
A. Clarissa, S. Curet, L. Boillereaux
Microwave-material interactions and electromagnetic propagation phenomena are important to optimize the microwave heating process of food samples. In this study, a 3D numerical modelling of a TE10 rectangular waveguide including microwave antenna and impedance matching elements is proposed. The microwave applicator is aimed to process both solid and liquid food samples. The model illustrates the standing wave patterns and microwave absorbed power within the cavity by taking into account the influence of the screw tuner, quartz windows, shorting plunger, and additional dielectric support plates. The results reveal the importance to consider the real cavity design and the precise dielectric characterization to predict accurate temperature profiles within the food product during the microwave heating. Such a model can be now be used to optimize the food sample geometry to achieve minimum reflected power and better heating uniformity.
{"title":"MICROWAVE PROCESSING OF FOOD SAMPLES: INFLUENCE OF CAVITY DESIGN AND DIELECTRIC PROPERTIES","authors":"A. Clarissa, S. Curet, L. Boillereaux","doi":"10.4995/ampere2019.2019.9911","DOIUrl":"https://doi.org/10.4995/ampere2019.2019.9911","url":null,"abstract":"Microwave-material interactions and electromagnetic propagation phenomena are important to optimize the microwave heating process of food samples. In this study, a 3D numerical modelling of a TE10 rectangular waveguide including microwave antenna and impedance matching elements is proposed. The microwave applicator is aimed to process both solid and liquid food samples. The model illustrates the standing wave patterns and microwave absorbed power within the cavity by taking into account the influence of the screw tuner, quartz windows, shorting plunger, and additional dielectric support plates. The results reveal the importance to consider the real cavity design and the precise dielectric characterization to predict accurate temperature profiles within the food product during the microwave heating. Such a model can be now be used to optimize the food sample geometry to achieve minimum reflected power and better heating uniformity.","PeriodicalId":277158,"journal":{"name":"Proceedings 17th International Conference on Microwave and High Frequency Heating","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115463050","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-10-15DOI: 10.4995/ampere2019.2019.9831
Á. H. Moreno, Rafael Hernández-Maqueda, I. Ballesteros, Carlos J. Torres-Miño
Previous studies on the microwave drying of corn seeds have shown that the process parameters employed play a very important role in determining the properties and quality of this grain (Gürsoy et al, 2013). Among these parameters, the drying temperature has a fundamental role (Nair et al, 2011). The main objective of this work is to evaluate the effect of temperature on drying time, energy consumption and germination rate of corn seeds after they have been dried with microwave energy. To achieve the proposed objective, the drying process of these seeds was carried out in a rotating turntable domestic microwave oven (LACOR Model 69330), with a capacity of 30 liters and a total output power of 900 W, fitted with a PID temperature controller Eurotherm 3216 L. In this oven, 100 g of corn seeds, with an initial humidity of approximately 20%, was heated up to 3 drying temperatures (35, 55 and 75 °C). The seeds were weighed every 30 minutes and the drying process was considered completed when a humidity of 12 % was obtained. For each drying temperature studied, the experiments were carried out in duplicate. In each experiment, the electrical energy consumption was measured using a FLUKE 1735 energy analyzer. A sample of the dried seeds was subject to germination tests in a petri dish using filter paper and a volume of distillate water of 20mL to achieve sufficient humidity for them to sprout. Table 1 shows the average values obtained from the variables evaluated for each drying temperature. Table 1. Results of the microwave drying experiments of the corn seeds at different temperatures and their germination tests. Drying temperature (ºC) Drying time to reach a humidity of 12% (min) Energy consumption (Wh) Germination rate (%) 35 345,0 880,3 90,0 55 118,5 330,0 81,3 75 73,5 183,9 12,0 As can be seen in Table 1, the temperature exerts a significant influence on the drying process and the germination rate of the corn seeds. An increase in the drying temperature causes a simultaneous decrease in drying time (∿ 78%) and in energy consumption (∿ 79%), which are very positive aspects. However, there is also an unacceptable decrease (∿ 87%) in the germination rate of the corn seeds. References Gürsoy, S., Choudhary, R., Watson, D.G. Int. J Agric. & Biol. Eng., 2013, 6, 1, 90–99.Nair, G.R., Li, Z., Gariepy, Y., Raghavan, V. Drying Technology, 2011, 29, 11, 1291-1296.
{"title":"Microwave drying of corn seeds: Effect of Temperature on Drying Time, Energy Consuption and Germination Rate","authors":"Á. H. Moreno, Rafael Hernández-Maqueda, I. Ballesteros, Carlos J. Torres-Miño","doi":"10.4995/ampere2019.2019.9831","DOIUrl":"https://doi.org/10.4995/ampere2019.2019.9831","url":null,"abstract":"Previous studies on the microwave drying of corn seeds have shown that the process parameters employed play a very important role in determining the properties and quality of this grain (Gürsoy et al, 2013). Among these parameters, the drying temperature has a fundamental role (Nair et al, 2011). The main objective of this work is to evaluate the effect of temperature on drying time, energy consumption and germination rate of corn seeds after they have been dried with microwave energy. To achieve the proposed objective, the drying process of these seeds was carried out in a rotating turntable domestic microwave oven (LACOR Model 69330), with a capacity of 30 liters and a total output power of 900 W, fitted with a PID temperature controller Eurotherm 3216 L. In this oven, 100 g of corn seeds, with an initial humidity of approximately 20%, was heated up to 3 drying temperatures (35, 55 and 75 °C). The seeds were weighed every 30 minutes and the drying process was considered completed when a humidity of 12 % was obtained. For each drying temperature studied, the experiments were carried out in duplicate. In each experiment, the electrical energy consumption was measured using a FLUKE 1735 energy analyzer. A sample of the dried seeds was subject to germination tests in a petri dish using filter paper and a volume of distillate water of 20mL to achieve sufficient humidity for them to sprout. Table 1 shows the average values obtained from the variables evaluated for each drying temperature. Table 1. Results of the microwave drying experiments of the corn seeds at different temperatures and their germination tests. Drying temperature (ºC) Drying time to reach a humidity of 12% (min) Energy consumption (Wh) Germination rate (%) 35 345,0 880,3 90,0 55 118,5 330,0 81,3 75 73,5 183,9 12,0 As can be seen in Table 1, the temperature exerts a significant influence on the drying process and the germination rate of the corn seeds. An increase in the drying temperature causes a simultaneous decrease in drying time (∿ 78%) and in energy consumption (∿ 79%), which are very positive aspects. However, there is also an unacceptable decrease (∿ 87%) in the germination rate of the corn seeds. References Gürsoy, S., Choudhary, R., Watson, D.G. Int. J Agric. & Biol. Eng., 2013, 6, 1, 90–99.Nair, G.R., Li, Z., Gariepy, Y., Raghavan, V. Drying Technology, 2011, 29, 11, 1291-1296.","PeriodicalId":277158,"journal":{"name":"Proceedings 17th International Conference on Microwave and High Frequency Heating","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115296248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-10-15DOI: 10.4995/ampere2019.2019.9882
J. Fukushima, H. Takizawa
Concentration of microwave E-field between material particles is considered to cause the enhancement of sintering1 and chemical reaction under microwave irradiation. For example, it is usually required 1700 °C to synthesize AlN by carbothermal reduction method using Al2O3 as a starting material, but microwave processing can proceed this process at 1200 °C2. To understand this phenomenon, it is necessary to understand an occurrence behavior of plasma and a chemical reaction related to radical species generated by a local E-field concentration. In addition, in material synthesis using a raw material powder of several mm, it is suggested that a selective heating in the powder scale occurs. However, to discuss this selective heating behavior on this scale, it is necessary to realize a quantitative temperature measurement system with independent of the emissivity of the material and several mm spatial resolution. In this study, we conducted an in-situ spectroscopy and two-color thermography to verify these non-equilibrium effects during microwave irradiation. For example, in the iron making process, it was investigated that CN plasma was generated, and this CN radical contributed to the reduction reaction (Fig. 1(a))3. In addition, the developed two-dimensional two-color thermography system with a high resolution of 8.8 mm/pixel was enable to discuss local temperature gradients quantitatively (Fig. 1(b)).
{"title":"IN-SITU SPECTROSCOPY AND TWO-COLOR THERMOGRAPHY DURING MICROWAVE IRRADIATION IN MATERIALS PROCESSING","authors":"J. Fukushima, H. Takizawa","doi":"10.4995/ampere2019.2019.9882","DOIUrl":"https://doi.org/10.4995/ampere2019.2019.9882","url":null,"abstract":"Concentration of microwave E-field between material particles is considered to cause the enhancement of sintering1 and chemical reaction under microwave irradiation. For example, it is usually required 1700 °C to synthesize AlN by carbothermal reduction method using Al2O3 as a starting material, but microwave processing can proceed this process at 1200 °C2. To understand this phenomenon, it is necessary to understand an occurrence behavior of plasma and a chemical reaction related to radical species generated by a local E-field concentration. In addition, in material synthesis using a raw material powder of several mm, it is suggested that a selective heating in the powder scale occurs. However, to discuss this selective heating behavior on this scale, it is necessary to realize a quantitative temperature measurement system with independent of the emissivity of the material and several mm spatial resolution. In this study, we conducted an in-situ spectroscopy and two-color thermography to verify these non-equilibrium effects during microwave irradiation. For example, in the iron making process, it was investigated that CN plasma was generated, and this CN radical contributed to the reduction reaction (Fig. 1(a))3. In addition, the developed two-dimensional two-color thermography system with a high resolution of 8.8 mm/pixel was enable to discuss local temperature gradients quantitatively (Fig. 1(b)).","PeriodicalId":277158,"journal":{"name":"Proceedings 17th International Conference on Microwave and High Frequency Heating","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116103829","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-10-15DOI: 10.4995/ampere2019.2019.9900
Metharak Jokpudsa, Supawat Kotchapradit, C. Thongsopa, T. Thosdeekoraphat
High-frequency magnetic field has been developed pervasively. The induction of heat from the magnetic field can help to treat tumor tissue to a certain extent. Normally, treatment by the low-frequency magnetic field needed to be combined with magnetic substances. To assist in the induction of magnetic fields and reduce flux leakage. However, there are studies that have found that high frequencies can cause heat to tumor tissue. In this paper present, a new magnetic application will focus on the analysis of the high-frequency magnetic nickel core with multi-coil. In order to focus the heat energy using a high-frequency magnetic field into the tumor tissue. The magnetic coil was excited by 915 MHz signal and the combination of tissues used are muscle, bone, and tumor. The magnetic power on the heating predicted by the analytical model, the power loss density (2.98e-6 w/m3) was analyzed using the CST microwave studio.
{"title":"ANALYSIS OF HIGH-FREQUENCY C-CORE MAGNETIC FLUX LEAKAGES FOR BONE TUMOR WITH INDUCTION HEATING BY USING MULTI-COIL","authors":"Metharak Jokpudsa, Supawat Kotchapradit, C. Thongsopa, T. Thosdeekoraphat","doi":"10.4995/ampere2019.2019.9900","DOIUrl":"https://doi.org/10.4995/ampere2019.2019.9900","url":null,"abstract":"High-frequency magnetic field has been developed pervasively. The induction of heat from the magnetic field can help to treat tumor tissue to a certain extent. Normally, treatment by the low-frequency magnetic field needed to be combined with magnetic substances. To assist in the induction of magnetic fields and reduce flux leakage. However, there are studies that have found that high frequencies can cause heat to tumor tissue. In this paper present, a new magnetic application will focus on the analysis of the high-frequency magnetic nickel core with multi-coil. In order to focus the heat energy using a high-frequency magnetic field into the tumor tissue. The magnetic coil was excited by 915 MHz signal and the combination of tissues used are muscle, bone, and tumor. The magnetic power on the heating predicted by the analytical model, the power loss density (2.98e-6 w/m3) was analyzed using the CST microwave studio.","PeriodicalId":277158,"journal":{"name":"Proceedings 17th International Conference on Microwave and High Frequency Heating","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122930319","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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