Spent coffee ground as renewable energy source: Evaluation of the drying processes

Tun, Maw Maw; Raclavská, Helena; Juchelková, Dagmar; Růžičková, Jana; Šafář, Michal; Štrbová, Kristína; Gikas, Petros

doi:10.1016/j.jenvman.2020.111204

Cited by 32 publications

(14 citation statements)

References 61 publications

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“…Other researchers have come to the same conclusion, analyzing the drying of spent coffee grounds at various temperatures. Tun et al [8] evaluated the drying of spent coffee grounds in a convective heater at the following temperatures: 75 °C, 90 °C, and 105 °C. e authors of the study showed that if the temperature increased from 75 to 90 °C or 105 °C respectively, better drying conditions were not obtained, especially for a thicker layer of spent co ee grounds.…”

Section: Kinetic Study Of the Drying Processmentioning

confidence: 99%

“…is is necessary both to ensure safe storage and to eliminate the possibility of microorganisms growth, especially molds [4]. Very few studies in the literature address the drying of spent co ee grounds using pilot-scale dryers [2][3][4][5][6][7][8]. Most of them are quite recent, demonstrating the growing interest of researchers in this subject due to the accelerated increase in co ee consumption in recent years and implicitly the amount of resulting spent co ee grounds, which is a valuable source of green energy.…”

Section: Introductionmentioning

confidence: 99%

“…e effectiveness of other spent coffee grounds drying techniques was also analyzed. For instance, Burdo et al [3] analyzed the infrared drying process, Solyom et al [7] studied the same process using microwaves, and Tun et al [8] tested the use of solar energy to dry spent coffee grounds. Tun et al [8] compared the results obtained for drying using solar energy with drying in a convective heater at temperatures of 75 °C, 90 °C, and 105 °C and with open-air drying.…”

Section: Introductionmentioning

confidence: 99%

“…For instance, Burdo et al [3] analyzed the infrared drying process, Solyom et al [7] studied the same process using microwaves, and Tun et al [8] tested the use of solar energy to dry spent coffee grounds. Tun et al [8] compared the results obtained for drying using solar energy with drying in a convective heater at temperatures of 75 °C, 90 °C, and 105 °C and with open-air drying. e experimental results indicated that the process of drying in the sun, in the open air, requires 10 hours to reach a final MR of 37%, while sun drying (at a temperature of 75 °C) reached a MR of 10% in 10 hours, and drying in the heater at the same temperature reached a MR of 7% in 6 hours.…”

Section: Introductionmentioning

confidence: 99%

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Isothermal Drying Kinetic Study of Spent Coffee Grounds Using Thermogravimetric Analysis

Bejenari

Lisa

Cernătescu

et al. 2022

International Journal of Chemical Engineering

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Drying coffee grounds involves high energy consumption and represents an important step in using coffee waste materials as green energy. This study analyzes the drying process using thermogravimetric analysis. The kinetics of the drying process of coffee grounds, containing equal proportions of Arabica and Robusta, were evaluated under isothermal conditions at various temperatures: 50, 60, 70, and 80°C, with sample layer thicknesses of 0.6, 1.2, 1.8, and 2.4 mm. The thermogravimetric curves obtained for the coffee grounds samples under conditions of constant temperature allowed the tracing of the drying curves (moisture content—drying time). The influence of the furnace air velocity on the drying and water evaporation process was analyzed. The drying rate has been established to be about 2.6 times slower than the rate of water evaporation under the same conditions; as a result the overall process is controlled by the effective water diffusion in the layer. This aspect is important in industrial practice for sizing tubular dryers. The activation energy was found to be influenced by the thickness of the coffee grounds layer subjected to the drying process and had values between 8.3 kJ/mol and 10.3 kJ/mol.

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Section: Kinetic Study Of the Drying Processmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Isothermal Drying Kinetic Study of Spent Coffee Grounds Using Thermogravimetric Analysis

Bejenari

Lisa

Cernătescu

et al. 2022

International Journal of Chemical Engineering

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“…Desain eksperimen yang digunakan pada penelitian ini menggunakan metode Taguchi Pemilihan media jemur sebagai faktor dalam penelitian ini karena panas matahari yang diserap oleh media jemur akan menjadi sumber panas untuk membantu penguapan secara konveksi dan secara konduksi, perbedaan media jemur tentu akan memberikan pengaruh yang berbeda terhadap penguapan. Ketebalan gabah sebagai faktor dalam penelitian ini karena ketebalan dalam proses pengeringan adalah parameter penting (Tun et al 2020), ketebalan yang berbeda tentu akan berbeda pengaruhnya terhadap penguapan. Frekuensi pembalikan sebagai faktor dalam penelitian ini karena tujuan pembalikan adalah untuk mengurangi tahanan selama proses difusi air sehingga berbentuk uap air yang bebas, frekuensi pembalikan yang berbeda tentu akan berbeda pengaruhnya terhadap penguapan.…”

Section: Metode Penelitianunclassified

Optimasi Parameter Proses Penjemuran Gabah Dengan Menggunakan Metode Taguchi

Fatah¹,

Wisnaningsih²

2020

PSN

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Proses penjemuran gabah bertujuan untuk mengeringkan gabah di bawah sinar matahari secara langsung tanpa perantara (terbuka). Pengeringan dengan cara ini menjadi pilihan umumnya petani karena menguntungkan secara ekonomi malaupun memiliki kekurangan terkait dengan penyusutan karena kehilangan selama proses penjemuran. Pada cuaca terik, proses pengeringan padi sampai pada tingkat GKP diperlukan waktu 2 – 3 hari. Penelitian ini ditujukan untuk mengoptimasi proses penjemuran dengan mempertimbangkan faktor-faktor yang mempengaruhi yaitu, media alas hamparan gabah (media jemur), tebal hamparan gabah dan frekuensi pembalikan. Penelitian dilakukan melalui sejumlah eksperimen dengan menggunakan desain eksperimen metode Taguchi L9 (33). Dari hasil perhitungan efek mean dan SNR diketahui bahwa frekuensi pembalikan menempati urutan ke-1, diikuti media jemur dan tebal gabah secara berturut-turut, pengaruhnya terhadap penyusutan kadar air, dan untuk mendapatkan proses penjemuran yang optimal, frekuensi pembalikan sebanyak 4 kali, kombinasi terpal talang dan terpal plastik sebagai media jemur, dan tebal gabah adalah 2 cm. Analisis varians mengungkapkan bahwa ke-3 faktor tidak siginifikan pengaruhnya terhadap penyusutan kadar air dengan kontribusi sebesar 77,17%.

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A novel process line for the valorization of industrial spent coffee grounds through coffee roasting technology and ultrasonic‐assisted extraction

Osorio-Arias

Quintero²,

Velásquez³

et al. 2022

J of Chemical Tech & Biotech

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BACKGROUND:The main by-product of the coffee industry is spent coffee grounds (SCG). To the best of our knowledge, this is the first occasion where industrial SCG has been used to build a batch-valorization line combining barrel coffee roasters as an innovative drying process and ultrasound-assisted extraction technology under the biorefinery concept, seeking to extract chlorogenic acids (CGA).RESULTS: A Probat Sample Barrel Roaster were used to determine the optimal temperature, volume flow of fan, and time for a novel drying method. Drying optimization was carried out in order to reach 5.0% moisture content, reduce water activity and maximize total CGA content. Optimal conditions of 140 °C, 160.0 m 3 h −1 and 11.43 min for temperature, volume flow of fan, and time, respectively, were obtained with a desirability of 70%. Likewise, the optimal temperature, power and frequency settings for an ultrasonic extraction procedure of CGA from dried SCG were evaluated. To maximize the total CGA content, the ultrasonic technique was optimized. Temperature 50 °C, frequency 37 kHz and power 100 W with a desirability of 80% were necessary for optimality. The study was completed with a kinetic analysis using a second-order rate model, Peleg's kinetic model and the phenomenological model. CONCLUSION: Industrial coffee by-products can be processed and valorizing using barrel coffee roasters as a novel technique. For process design, the kinetic parameters of ultrasound-assisted extraction are a helpful tool. A new mathematical model is presented that takes into account the impact of changing temperature on the ultrasonic process.

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Spent coffee ground as renewable energy source: Evaluation of the drying processes

Cited by 32 publications

References 61 publications

Isothermal Drying Kinetic Study of Spent Coffee Grounds Using Thermogravimetric Analysis

Isothermal Drying Kinetic Study of Spent Coffee Grounds Using Thermogravimetric Analysis

Optimasi Parameter Proses Penjemuran Gabah Dengan Menggunakan Metode Taguchi

A novel process line for the valorization of industrial spent coffee grounds through coffee roasting technology and ultrasonic‐assisted extraction

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