scholarly journals Laboratory Model Studies on the Drying Efficiency of Transformer Cellulose Insulation Using Synthetic Ester

Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3467 ◽  
Author(s):  
Piotr Przybylek ◽  
Hubert Moranda ◽  
Hanna Moscicka-Grzesiak ◽  
Mateusz Cybulski
Keyword(s):  
Laboratory Tests ◽  
Weight Ratio ◽  
Major Effect ◽  
Laboratory Model ◽  
Drying Process ◽  
Drying Time ◽  
Model Studies ◽  
Synthetic Ester ◽  
Drying Efficiency ◽  
Cellulose Insulation

This paper presents the results of laboratory tests of cellulose insulation drying with the use of synthetic ester. The effectiveness of the drying process was investigated depending on the initial moisture of cellulose samples (2%, 3%, and 4%), ester temperature (55, 70, and 85 °C), initial moisture of the ester (70, 140, and 220 ppm), drying time (48, 96, and 168 h), and the weight ratio of cellulosic materials to ester (0.067 and 0.033). A large influence of temperature and time of drying on the efficiency of the drying process was found. This is important information due to the application of the results in the transformers drying procedure. The heating and drying ester unit should provide the highest possible temperature. For the assumed experiment conditions the initial moisture of the ester had little effect on the drying efficiency. An ester with a moisture content below 140 ppm can still be considered as meeting the requirements for drying cellulose with significant moisture. The weight ratio of cellulose products to ester has no major effect on drying efficiency during cellulose drying by circulating dry ester.

scholarly journals Application of Synthetic Ester for Drying Distribution Transformer Insulation—The Influence of Cellulose Thickness on Drying Efficiency

Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3874 ◽  
Author(s):  
Piotr Przybylek ◽  
Hubert Moranda ◽  
Hanna Moscicka-Grzesiak ◽  
Dominika Szczesniak
Keyword(s):  
Complex Problem ◽  
Drying Methods ◽  
Drying Process ◽  
Synthetic Ester ◽  
Breakdown Probability ◽  
Drying Efficiency ◽  
High Level ◽  
Transformer Insulation ◽  
Cellulose Insulation ◽  
Cellulose Materials

A high level of insulation moisture in a transformer increases the breakdown probability and forces a reduction of its load. Therefore, there is a need to dry the transformer insulation. For technical reasons, there are some restrictions on the use of common drying methods for cellulose insulation available on the market. The aim of the research was to check the possibility of using synthetic ester for effective drying of cellulose materials of various thickness and an evaluation of the drying dynamics. The replacement of mineral oil with a synthetic ester caused a reduction of moisture in paper and thin pressboard by one percentage point. It was possible in the case of drying these materials for seven days at a temperature of 70 °C. The effects of drying were much smaller in the case of thicker cellulose samples. This paper also shows the complex problem of simultaneously drying materials of different thicknesses. Drying thin paper and thick pressboard at the same time significantly slows down the drying process of the pressboard. Presented results will be used to develop a procedure for drying the transformer insulation system using a synthetic ester.

scholarly journals Modifikasi Pengering Tipe Tray Dryer Dengan Penambahan Insulator

2020 ◽  
Vol 4 (4) ◽  
pp. 422-431
Author(s):  
Iqbal Fahri Tobing ◽  
Mustaqimah Mustaqimah ◽  
Raida Agustina
Keyword(s):  
Energy Consumption ◽  
Thermal Energy ◽  
Performance Test ◽  
Raw Materials ◽  
Electric Energy ◽  
Electrical Energy ◽  
Energy Calculation ◽  
Drying Process ◽  
Drying Time ◽  
Drying Efficiency

Abstrak. Pengering tipe Tray Dryer merupakan salah satu alat pengering rak atau pengering kabinet yang dapat digunakan untuk mengeringkan berbagai jenis bahan baku makanan. Alat pengering ini dirancang dengan tipe paralel flow tray dimana udara panas yang dihasilkan akan disirkulasikan sejajar dengan permukaan rak pengering dan bekerja menggunakan sumber energi listrik. Penelitian ini bertujuan untuk memodifikasi pengering tray dryer dengan penambahan insulator dan mengetahui konsumsi energi alat pengering tray dryer pada pengeringan kunyit. Parameter pengujian uji kinerja alat tanpa bahan meliputi distribusi suhu, kelembaban relatif dan kecepatan aliran udara dan untuk perhitungan konsumsi energi meliputi penggunaan energi listrik, perhitungan energi thermal, energi mengeringkan bahan, energi untuk menguapkan air bahan, efisiensi pengeringan, energi kipas dan kehilangan energi melalui cerobong. Pada pengujian pengering tray dryer suhu yang digunakan adalah 55°C. Hasil penelitian menunjukkan bahwa secara fungsional dan struktural alat pengering tray dryer setelah dimodifikasi dengan melapisi dinding luar ruang pengering dapat beroperasi dengan baik, proses pengeringan lebih cepat dan energi yang digunakan juga sedikit dibandingkan dengan sebelum dimodifikasi. Konsumsi energi listrik pada alat pengering tray dryer setelah dimodifikasi pada saat proses pengeringan dengan suhu 35oC selama 6,5 jam sebesar 35,33 kWh (127,2 MJ), pada suhu 45oC sebesar 24,26 kWh (88,06 MJ) dengan lamanya pengeringan selama 4,5 jam dan suhu 55oC sebesar 18,89 kWh (68,01 MJ) dengan lama pengeringan selama 3,5 jam, hal ii disebabkan lama pengeringan merupakan salah satu faktor yang menyebabkan besar kecilnya konsumsi energi listrik. Konsumsi energi thermal selama proses pengeringan dengan suhu 35°C adalah sebesar 17,53 MJ, suhu 45°C sebesar 19,54 MJ dan suhu 55°C sebesar 21,34 MJ. Berdasarkan hasil kalkulasi antara energi listrik dan energi thermal didapatkan efisiensi pengeringan pada suhu 35°C sebesar 27,80%, suhu 45°C sebesar 22,2% dan suhu 55°C sebesar 31,4%.Modification Of Tray Dryer With InsulatorAbstract. Tray Dryer is a type of dryer or cabinet dryer that can be used to dry various types of food raw materials. This dryer is designed with a parallel flow tray type where the hot air generated will be circulated parallel to the surface of the drying rack and work using an electric energy source. This study aims to modify the tray dryer with the addition of an insulator and determine the energy consumption of dryer dryers in turmeric drying. The test parameters of the performance test of equipment without material include temperature distribution, relative humidity and air flow velocity and for the calculation of energy consumption including the use of electrical energy, thermal energy calculation, energy drying material, energy to evaporate material water, drying efficiency, fan energy and energy loss through chimney. In testing the tray dryer dryer the temperature used is 55 ° C. The results showed that functionally and structurally the tray dryer after being modified by covering the outer walls of the drying chamber could operate well, the drying process was faster and the energy used was also less compared to before it was modified. Electric energy consumption in the tray dryer after being modified during the drying process with a temperature of 35oC for 6.5 hours amounted to 35.33 kWh (127.2 MJ), at a temperature of 45oC of 24.26 kWh (88.06 MJ) with a duration drying for 4.5 hours and a temperature of 55oC of 18.89 kWh (68.01 MJ) with a drying time of 3.5 hours, this is due to the length of drying is one of the factors causing the size of the electrical energy consumption. The consumption of thermal energy during the drying process with a temperature of 35 ° C is 17.53 MJ, a temperature of 45 ° C is 19.54 MJ and a temperature of 55 ° C is 21.34 MJ. Based on the results of calculations between electrical energy and thermal energy obtained drying efficiency at a temperature of 35 ° C at 27.80%, a temperature of 45 ° C at 22.2% and a temperature of 55 ° C at 31.4%

Kinetic and Thermodynamic Characteristics of Seaweed Dried in the Convective Air Drier

2010 ◽  
Vol 6 (5) ◽  
Author(s):  
Rosalam Sarbatly ◽  
Tracy Wong ◽  
Awang Bono ◽  
Duduku Krishnaiah
Keyword(s):  
Specific Heat ◽  
Air Temperature ◽  
Flow Rate ◽  
Thermodynamic Characteristics ◽  
Drying Kinetics ◽  
Drying Rate ◽  
Drying Process ◽  
Drying Time ◽  
Sun Drying ◽  
Drying Efficiency

This study reveals the drying kinetics, specific heat and enthalpy of seaweed dried in the convective air drier. Comparison between convective hot air and sun drying process was also studied. At 50°C air temperature with 23.45 percent relative humidity and 1.55 ms-1air flow rate, it has been found that the moisture removal required 4 hours to reach moisture content of 19.66 percent wet basis with its drying rate at 0.28 x 10-3 kg water h-1. The data of drying rate showed that the drying process took place in the falling rate period. The specific heat and initial enthalpy were found to be 1.3842 kJkg-1°C-1 and 1672.69 kJkg-1, respectively. It was observed that the drying kinetics, specific heat, and enthalpy values vary significantly as functions of air temperature which seem to have more effect when compared to air flow rate and seaweed loading. Hence, the best method for seaweed drying was to use convective air system rather than sun drying because it required less drying time and has better drying efficiency.

scholarly journals Influence of Various Temperatures on the Drying Time of 220/66 KV Transformer Insulations in Vapour Phase Drying Process

2020 ◽  
Vol 9 (5) ◽  
pp. 645-651
Keyword(s):  
Moisture Content ◽  
Vapour Phase ◽  
Vital Role ◽  
Drying Process ◽  
Drying Time ◽  
Moisture Extraction ◽  
High Level ◽  
Transformer Insulation ◽  
Cellulose Insulation ◽  
Very High

Cellulose based insulation in the form of different papers and pressboard play a vital role in transformer manufacturing as very high level of voltages are encountered during transformer operation. Cellulose being hygroscopic in nature contains 8-10% moisture by weight. The life of a transformer is critically dependant on the state of cellulose insulation so much so that, paper with 1.5% moisture content ages 10 times faster than with only 0.3% moisture. For obvious reasons, it is very important that the moisture is removed from transformer insulation. As of today, the latest technology available for this moisture extraction is the vapour phase drying process. This paper evaluates the influence of temperatures at various locations on the drying time of two 220kv transformer insulations in vapour phase drying process.

scholarly journals Influence of Various Temperatures on the Drying Time of 132 KV Transformer Insulations in Vapour Phase Drying Process

2020 ◽  
Vol 9 (3) ◽  
pp. 3072-3078
Keyword(s):  
Moisture Content ◽  
Vapour Phase ◽  
The State ◽  
Vacuum Drying ◽  
Drying Process ◽  
Drying Time ◽  
Insulation Materials ◽  
Transformer Insulation ◽  
Cellulose Insulation ◽  
Very High

Transformers are required to handle very high levels of voltage and hence proper insulation is very important in transformers. As of now, the most preferred form of insulation in transformers is cellulose based. The state of cellulose insulation materials like paper & pressboards determines the life end of a transformer. Paper with 1.5% moisture content ages 10 times faster than with only 0.3% moisture. For obvious reasons, it is very important that the moisture is removed from transformer insulation. Vacuum drying has been conventionally used in industries for insulation drying but, as of today the latest technology available is the vapour phase drying process. This paper evaluates the influence of temperatures at various locations on the drying time of the 132kv transformer insulations in vapour phase drying process.

scholarly journals Assessment of Concentration of Mineral Oil in Synthetic Ester Based on the Density of the Mixture and the Capacitance of the Capacitor Immersed in It

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1839
Author(s):  
Hubert Moranda ◽  
Jaroslaw Gielniak ◽  
Ireneusz Kownacki
Keyword(s):  
Mineral Oil ◽  
Power Transformers ◽  
Scientific Achievement ◽  
Similar Measurement ◽  
Drying Process ◽  
Mixture Density ◽  
Synthetic Ester ◽  
Capacitance Method ◽  
Oil Concentration ◽  
Cellulose Insulation

This research was carried out during the realization of a project with the aim of developing a method of drying cellulose insulation in power transformers by using synthetic ester. Unfortunately, during the drying process, the ester is systematically contaminated with mineral oil, which reduces its water absorption. Information on the oil concentration in the mixture is needed in two cases: when deciding how to treat the mixture, and during the treatment. The article presents two methods: (1) based on the measurement of the mixture density, and (2) based on the measurement of a capacitor immersed in the mixture. The most important scientific achievement of the work is the proof, by way of experiment, of the existence of a relationship between the concentration of mineral oil and (1) the density of the mixture, and (2) the capacity of the capacitor immersed in it. These relations are presented in the form of equations for which the error calculus showed that the uncertainty of measurement for both methods did not exceed 3 p. %. Due to the similar measurement error of both methods, the authors recommend the capacitance method as easier to use, especially online.

Konsumsi Energi Pada Alat Pengering Surya dan Tipe Bak Untuk Pengeringan Biji Kakao

2019 ◽  
Vol 17 (3) ◽  
Author(s):  
Lamhot P. Manalu
Keyword(s):  
Specific Energy ◽  
Fossil Fuels ◽  
Negative Impact ◽  
Solar Irradiation ◽  
Drying Process ◽  
Food Industries ◽  
Solar Dryer ◽  
Agricultural Applications ◽  
Drying System ◽  
Drying Efficiency

Crop drying is essential for preservation in agricultural applications. It is performed either using fossil fuels in an artificial mechanical drying process or by placing the crop under the open sun. The first method is costly and has a negative impact on the environment, while the second method is totally dependent on the weather. The drying process requires a lot of energy in relation to the amount of water that must be evaporated from the product. It is estimated that 12% of the total energy used by the food industries and agriculture absorbed in this process. Due to the limitation of energy resources, it is important to keep researching and developing of diversification and optimization of energy This study aims to assess the use of energy for cocoa drying using solar energy dryer and bin-type dryer, as well as to determine the drying efficiency of each type of dryer. The results showed that the efficiency of the solar dryer drying system ranges between 36% to 46%, while the tub-type dryers between 21.7% to 33.1%. The specific energy of solar dryer ranged from 6.17-7.87 MJ / kg, while the tub-type dryers 8.58-13.63 MJ / kg. Dryer efficiency is influenced by the level of solar irradiation and the amount of drying load, the higher the irradiation received and more cocoa beans are dried, the drying efficiency is also higher and the specific energy further down.Proses pengeringan memerlukan banyak energi sehubungan dengan banyaknya air yang harus diuapkan dari bahan yang dikeringkan. Pengeringan dapat dilakukan dengan menggunakan pengering mekanis berbahan bakar fosil atau dengan menempatkan produk di bawah matahari terbuka. Metode pertama adalah mahal dan memiliki dampak negatif pada lingkungan, sedangkan metode kedua sangat tergantung pada cuaca. Diperkirakan bahwa 12% dari total energi yang dipergunakan oleh industri pangan dan pertanian diserap untuk proses ini. Mengingat semakin terbatasnya sumber energi bahan bakar minyak maka usaha diversifikasi dan optimasi energi untuk pengeringan perlu terus diteliti dan dikembangkan. Salah satunya adalah pemanfaatan energi surya sebagai sumber energi terbarukan. Penelitian ini bertujuan untuk mengkaji penggunaan energi untuk pengeringan kakao dengan memakai pengering energi surya dan pengering tipe bak, serta untuk mengetahui efisiensi pengeringan dari masing-masing tipe pengering. Hasil kajian menunjukkan bahwa efisiensi total sistem pengeringan alat pengering surya berkisar antara 36% dan 46%, sedangkan pengering tipe bak antara 21.7% dan 33.1%. Kebutuhan energi spesifik alat pengering surya berkisar antara 6.17-7.87 MJ/kg, sedangkan alat pengering tipe bak 8.58-13.63 MJ/kg. Efisiensi alat pengering dipengaruhi oleh tingkat iradiasi surya dan jumlah beban pengeringan, semakin tinggi iradiasi yang diterima pengering serta semakin banyak biji kakao yang dikeringkan, maka efisiensi pengeringan juga semakin tinggi dan kebutuhan energi spesifik semakin turun.Keywords: energy, efficiency, cocoa, solar dryer, bin-type dryer.

CATFISH DRYING (Clarias Batraclus) USING ‘TEKO BERSAYAP’ SOLAR DRYER

2012 ◽  
Vol 2 (1) ◽  
pp. 14-20
Author(s):  
Yuwana Yuwana
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Ambient Temperature ◽  
Drying Rate ◽  
Drying Process ◽  
Drying Time ◽  
Ambient Relative Humidity ◽  
Solar Dryer

Experiment on catfish drying employing ‘Teko Bersayap’ solar dryer was conducted. The result of the experiment indicated that the dryer was able to increase ambient temperature up to 44% and decrease ambient relative humidity up to 103%. Fish drying process followed equations : KAu = 74,94 e-0,03t for unsplitted fish and KAb = 79,25 e-0,09t for splitted fish, where KAu = moisture content of unsplitted fish (%), KAb = moisture content of splitted fish (%), t = drying time. Drying of unsplitted fish finished in 43.995 hours while drying of split fish completed in 15.29 hours. Splitting the fish increased 2,877 times drying rate.

Influencia de las condiciones de secado solar en la coloración de plantas medicinales

2019 ◽  
pp. 28-34
Author(s):  
Margarita Castillo-Téllez ◽  
Beatriz Castillo-Téllez ◽  
Juan Carlos Ovando-Sierra ◽  
Luz María Hernández-Cruz
Keyword(s):  
Medicinal Plants ◽  
Forced Convection ◽  
Rural Areas ◽  
Color Change ◽  
Drying Process ◽  
Scientific Medicine ◽  
Drying Time ◽  
Bacterial Proliferation ◽  
Wide Range ◽  
Very High

For millennia, humans have used hundreds of medicinal plants to treat diseases. Currently, many species with important characteristics are known to alleviate a wide range of health problems, mainly in rural areas, where the use of these resources is very high, even replacing scientific medicine almost completely. This paper presents the dehydration of medicinal plants that are grown in the State of Campeche through direct and indirect solar technologies in order to evaluate the influence of air flow and temperature on the color of the final product through the L* a* scale. b*, analyzing the activity of water and humidity during the drying process. The experimental results showed that the direct solar dryer with forced convection presents a little significant color change in a drying time of 400 min on average, guaranteeing the null bacterial proliferation and reaching a final humidity between 9 % and 11 %.

scholarly journals Cherry Tomato Drying: Sun versus Convective Oven

Horticulturae ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 40
Author(s):  
Vincenzo Alfeo ◽  
Diego Planeta ◽  
Salvatore Velotto ◽  
Rosa Palmeri ◽  
Aldo Todaro
Keyword(s):  
Moisture Content ◽  
Initial Moisture Content ◽  
Drying Process ◽  
Drying Time ◽  
Oven Drying ◽  
Sun Drying ◽  
Different Temperatures ◽  
Final Water Content ◽  
Drying Curves ◽  
Drying Conditions

Solar drying and convective oven drying of cherry tomatoes (Solanum lycopersicum) were compared. The changes in the chemical parameters of tomatoes and principal drying parameters were recorded during the drying process. Drying curves were fitted to several mathematical models, and the effects of air temperature during drying were evaluated by multiple regression analyses, comparing to previously reported models. Models for drying conditions indicated a final water content of 30% (semidry products) and 15% (dry products) was achieved, comparing sun-drying and convective oven drying at three different temperatures. After 26–28 h of sun drying, the tomato tissue had reached a moisture content of 15%. However, less drying time, about 10–11 h, was needed when starting with an initial moisture content of 92%. The tomato tissue had high ORAC and polyphenol content values after convective oven drying at 60 °C. The dried tomato samples had a satisfactory taste, color and antioxidant values.

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