Investigation on the microwave drying kinetics and pumping phenomenon of lignite spheres

Fu, B.A.; Chen, Meiqian

doi:10.1016/j.applthermaleng.2017.06.034

Cited by 52 publications

(9 citation statements)

References 32 publications

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“…Gel ombang mi kro adal ah gelombang elektromagnetik dengan frekuensi 300 MHz-300 GHz (Fu, Chen, & Song, 2017;Metaxas & Meredith, 2008). Pada pengeringan menggunakan gelombang mikro terjadi pemanasan dielektrik yaitu energi gelombang mikro dikonversi dalam bahan secara langsung menjadi energi panas melalui friksi antar molekul.…”

Section: Pendahuluanunclassified

Performa dan Analisis Konsumsi Energi Pengeringan Rumput Laut Menggunakan Energi Gelombang Mikro

Hakim¹,

Handoyo²,

Prasetyo³

2020

JPBKP

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Pengeringan menggunakan energi gelombang mikro menjadi alternatif agar pengeringan berjalan lebih cepat tanpa terpengaruh kondisi cuaca. Namun performa dan efisiensi energi dalam mengeringkan rumput laut belum diketahui. Tujuan penelitian ini adalah untuk mengetahui performansi pengeringan rumput laut menggunakan energi gelombang mikro (microwave) dan analisa konsumsi energinya. Metode yang digunakan ialah mengeringkan rumput laut segar dalam oven gelombang mikro secara batch. Dalam proses pengeringan dilakukan variasi level daya (400, 500, 600 watt) ke dalam oven gelombang mikro dan variasi ketebalan rumput laut (3, 5, 7 cm). Parameter yang diamati meliputi rasio kadar air (moisture ratio/MR), laju pengeringan (g/menit), difusi efektif air/Deff (mm2/detik), specific energy consumption/SEC (J/g H2O) dan efisiensi energi (%). Hasil penelitian menunjukkan, level daya magnetron 600 watt menghasilkan MR terendah (0,19), laju pengeringan tertinggi (13,15 g/menit) dan Deff tertinggi (2,28 x 10-2 mm2/detik). Rumput laut ketebalan 3 cm memperoleh MR terendah (0,05), laju pengeringan tertinggi (6,42 g/menit) dan Deff tertinggi (9,42 x 10-2 mm2/detik). SEC pengeringan sebesar 4,38-4,51 J/g H2O dan efisiensi energi 22,56-23,42% untuk level daya 400-600 watt. Perbedaaan level daya tidak memberikan pengaruh signifikan terhadap SEC dan efisiensi. Sedangkan variasi ketebalan rumput laut antara 3 cm dan 7 cm memberi hasil yang berbeda. SEC terendah diperoleh pada perlakuan rumput laut tebal 3 cm yaitu 2,96 J/g H2O sementara efisiensi tertinggi pada rumput laut dengan tebal 5 cm yaitu 22,93%.Oleh karena itu pengeringan rumput laut menggunakan energi gelombang mikro dengan level daya 600 watt dan ketebalan 3 cm menghasilkan performasi dan konsumsi energi yang lebih baik. AbstractMicrowave drying becomes alternative method to get faster process without being influenced by weather. However performance and energy efficiency of microwave drying for seaweed are still unknown. This research aims to find out performance of seaweed drying in microwave oven as well as energy consumption analysis. The method used was drying seaweed in microwave oven. Seaweed drying was conducted at various power level (400, 500, 600 watt) and thickness of seaweed (3, 5, 7 cm). Observed parameters were moisture ratio/MR, drying rates (g/min), effective diffusion/Deff (mm2/s), specific energy consumption/SEC (J/g H2O) and energy efficiency (%). Result of research showed that power level, 600 watt of magnetron produced lowest MR (0,19), highest drying rate and Deff i.e 13.15 g/min and 2.28 x 10-2 mm2/s respectively. Seaweed 3 cm thickness achieved lowest MR (0.05), highest drying rates 6.42 g/min and Deff 9.42 x 10-2 mm2/s. SEC of drying were 4.38-4.51 J/g H2O while energy efficiency were 22.56-23.42 % for 400-600 watt. Differences of power level have not given significant effect to SEC and efficiency values. Whereas differences of seaweed thickness between 3 cm and 7 cm have given significant effect. Seaweed in 3 cm thickness resulted in the lowest SEC i.e 2.96 J/g H2O, however, the highest efficiency energy was 5 cm thickness i.e 22.93%. Therefore drying seaweed utilize microwave energy of 600 watt power level and 3 cm thickness generated better performance and energy consumption.

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Section: Pendahuluanunclassified

Performa dan Analisis Konsumsi Energi Pengeringan Rumput Laut Menggunakan Energi Gelombang Mikro

Hakim¹,

Handoyo²,

Prasetyo³

2020

JPBKP

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“…Recently, various novel drying techniques such as infrared drying, microwave drying, vacuum drying, and hybrid drying (e.g., hot airinfrared, hot air-vacuum, microwave-infrared and microwave-vacuum drying) have become very popular (Ando et al, 2019;Fu, Chen, & Song, 2017;Mäkelä & Geladi, 2015;Onwude, Hashim, Abdan, Janius, & Chen, 2019). Among these methods, microwave drying has attracted significant attention from researchers because of its high drying velocity, relatively low energy consumption and its ability to preserve the good nutrients.…”

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confidence: 99%

Microwave intermittent drying characteristics of camellia oleifera seeds

Huang

Men

Tang

et al. 2020

J Food Process Engineering

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This paper reports on an experimental investigation of the drying characteristics and kinetics of camellia oleifera seeds under microwave intermittent drying conditions. The effects of key parameters such as microwave power, heating time, and the length of the intermittent time are discussed in detail. The energy consumption in the drying process along with the main quality parameters of camellia oil, namely the peroxide and acid values, have also been determined and compared with hot‐air drying. Results show that the microwave drying curve consists of an acceleration rate period, a constant rate period and a falling rate period. As the microwave power and heating time increase, the drying time decreases. While as the length of the intermittent time increases, the drying time increases. The hot‐air drying time was found to be much longer than microwave drying time, and the energy consumed during hot‐air drying was also several hundred times higher than that used during microwave intermittent drying. The acid and peroxide values of camellia oil after hot‐air and microwave drying were both within the allowable range in the National Standard of China. The Midilli and Kucuk model was the best model to describe the kinetics of the drying process.Practical applicationsDrying is the first step in the processing of camellia oleifera seeds, which not only affects the storage of camellia oleifera seeds, but also affects the quality of camellia oil, and has thus become a research hotspot in recent years. However, several disadvantages of hot‐air drying have been identified like the slowness of the drying process and the relatively large energy consumption. Therefore, finding a drying method that is more suitable is necessary. Microwave intermittent drying is a type of discontinuous drying. The moisture and temperature inside the material can be evenly redistributed during the intermittent time, so that the material is not overheated. This feature of preserving the quality of the products to be dried has made microwave intermittent drying attractive and has been successfully applied to agricultural, forestry, and food products.

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“…It was probably caused by the moisture content remained high on this treatment. As stated by Fu et al (2017), the sufficient moisture content in the material and the energy from the microwave lead to constant DR beyond the maximum DR point.…”

Section: Drying Ratesmentioning

confidence: 94%

“…Increasing the weight load also influenced the thickness of the seaweed that was placed in the cavity. The thickness of the material under microwave energy affects the electromagnetic wave's penetration (Fu, Chen & Song, 2017;Hakim, Handoyo & Prasetyo, 2020b;Jiang, Dang, Tan, Pan & Wei, 2017). The optimum penetration allows increasing friction among water molecules in the seaweed.…”

Section: Moisture Ratiomentioning

confidence: 99%

Design and Performance of Scaled-Up Microwave Dryer for Seaweed Drying

Hakim

Handoyo

Prasetya

2020

Squalen Bull. Marine Fisheries Postharvest Biotech.

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Direct sunlight is commonly used to dry fresh seaweed by artisanal farmers in Indonesia due to its low cost and ease of handling. Nevertheless, this method poses some drawbacks such as lengthy duration, weather dependency and quality degradation. The application of microwave technology in food processing has progressed dramatically, including in the drying process. The microwave drying method is more efficient and can shorten the processing time. This study aimed to describe a large-scale microwave dryer (MD) design and performance to assist the fresh seaweed drying process. The design concept applies microwave energy with a volumetric heating feature to accelerate the seaweed drying process without damaging its functional groups. The MD dimensions were 2410 (l) x 270 (w) x 210 (h) mm with a dryer capacity of up to six kilograms, an enlarged cavity and multiple magnetrons. The main components of the MD were cavity, air circulation system, drying system and control system. According to the performance testing, the MD’s optimum performance was at a power level setting of P7 and six kilograms load. At this setting, we obtained a dried seaweed with a moisture ratio of 0.68±0.05, drying rate of 30.29±1.32 g/min, specific energy consumption of 3.96±0.08 MJ/kg H2O and energy efficiency of 58.45±2.65%. The total power of the P7 setting operation required 2.00 kW. Fourier-Transform Infrared (FTIR) spectra showed that the functional groups of the dried seaweed were unaltered.

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Investigation on the microwave drying kinetics and pumping phenomenon of lignite spheres

Cited by 52 publications

References 32 publications

Performa dan Analisis Konsumsi Energi Pengeringan Rumput Laut Menggunakan Energi Gelombang Mikro

Performa dan Analisis Konsumsi Energi Pengeringan Rumput Laut Menggunakan Energi Gelombang Mikro

Microwave intermittent drying characteristics of camellia oleifera seeds

Design and Performance of Scaled-Up Microwave Dryer for Seaweed Drying

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