Ibrahim, Alim J (2017) Studi Eksperimen Pengaruh Kecepatan Fluidisasi dan Jenis Bed Pengeringan Terhadap Unjuk Kerja Swirling Fluidized Bed Coal Dryer Tanpa Pengarah Aliran Berbentuk Cone. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Menurut BP Statistical Review pada tahun 2015, Indonesia merupakan salah satu negara dengan kenaikan konsumsi batubara terbesar di dunia, yaitu sebesar 15%. Walaupun konsumsi batubara Indonesia mengalami peningkatan, namun kualitas batubara di Indonesia dapat terbilang masuk kedalam kelas menengah kebawah dari peringkat seluruh batubara dunia. Kualitas yang kurang baik tersebut disebabkan oleh moisture content batubara Indonesia yang cukup tinggi. Salah satu metode yang baik untuk digunakan dalam proses pengeringan adalah dengan memfluidisasi suatu benda padat (fluidized bed).
Rangkaian alat ini didesain untuk mengeringkan batubara dengan udara yang berperan sebagai media pengering. Kecepatan udara pengeringan akan divariasikan pada 75%, 100%, dan 125% dari kecepatan minimum fluidisasi. Batubara yang akan dikeringkan berbentuk granular dengan diameter rata-rata sebesar ± 6 mm. Beban pengeringan di setiap variasi kecepatan adalah 600 gram. Untuk mendapatkan aliran swirl, udara di hembuskan oleh sentrifugal blower menuju vane pengarah aliran dengan sudut 10o. Pada setiap menit pengeringan, dicatat temperatur dan relative humidity dari udara pengering. Diambil pula sampel batubara sebanyak ±3 gram untuk menghitung moisture content batubara.
Dari penelitian ini didapatkan bahwa drying rate rata-rata pada kecepatan 15.9 m/s, 21.21 m/s, dan 25.61 m/s berturut-turut adalah 5.63 gr/min, 7.17 gr/min, dan 7.714 gr/min. Berdasarkan waktu pengeringan, pada menit ke-1 hingga menit ke-6 drying rate terbesar dicapai oleh kecepatan fludisasi 25.61 m/s (125% Umf), pada menit ke-6 hingga menit ke-14 drying rate terbesar dicapai oleh kecepatan fluidisasi 21.21 m/s (100% Umf), sedangkan pada menit ke-14 hingga menit ke-22 drying rate terbesar dicapai pada kecepatan fludisasi 15.9 m/s (75% Umf). Massa air yang berpindah selama 22 menit pengeringan pada kecepatan 15.9 m/s, 21.21 m/s, dan 25.61 m/s masing masing adalah 112.74 gram, 137 gram, dan 146.39 gram. Data perpindahan massa yang didapatkan melalui sisi udara dan sisi batubara mengalami perbedaan sebesar 2.17%, 2.816%, dan 7.01% masing masing pada kecepatan fluidisasi 15.9 m/s, 21.21 m/s, dan 25.61 m/s. Melalui foto dan video selama proses pengeringan berlangsung, terlihat bahwa pada saat bed batubara telah terfluidisasi maka tidak akan terdapat batubara yang mengumpul pada bagian tengah dari drying chamber.
=======================================================================According to BP Statistical Review in 2015, Indonesia is one of the countries with the largest increasing of coal consumption in the world, which is 15%. Eventhough Indonesia’s coal consumption has increased, but the quality of coal in Indonesia can only be considered into middle-low rank coal of all the world's coal. The poor quality of indonesian coal is caused by moisture contain in that coal. Indonesian coal needed a special treatment before it used so that the coal calorific value can be increased. One of the best treatment is to dry the coal in an fluidized bed drying, as one of the vaporization method. The vaporization method, drying process which done by exhaling hot air into coal specimens, is considered as one of the best method for drying the coal. And also swirl flow with high turbulence intensity is expected to boost heat & mass transfer rates.
Structure of this tools is designed to drying coals with air acting as the drying medium. Drying air velocity will be varied at 75%, 100%, and 125% of the minimum fluidization velocity. Coal to be dried is first broken into granular shape with an average diameter of ± 6 mm. Drying load in each speed variation is 600 grams. To obtain swirl flow, the air is blown by a centrifugal blower to steering vanes with angles of 10°. Granules of coals will be placed above the flow steering vane, ie the place to be a drying bed. At each minute of the drying process, the temperature and relative humidity of air was noted. Some coal as much as ± 3 grams are taken each minute to calculate coal’s moisture content.
From this research it is found that the average of drying rate at a speed of 15.9 m/s, 21.21 m/s, and 25.61 m/s respectively are 5.63 gr/min, 7.17 gr/min, dan 7.714 gr/min. Based on drying time, the biggest drying rate on 1st to 6th minutes of drying is achieved by the speed of 25.61 m/s (125% Umf), in the 6th to 14th minutes of drying the biggest drying rate is achieved by the speed of 21.21 m/s (100% Umf), while in the range of 14th to 22nd minutes of drying the greatest drying rate was achieved at 15.9 m / s (75% Umf). The total of water mass transfer for 22 minutes of drying at a speed of 15.9 m/s, 21.21 m/s, and 25.61 m/s respectively are 112.74 grams, 137 grams, and 146.39 grams. The mass transfer data obtained through the air and coal sides experienced a difference of 2.17%, 2.816%, and 7.01% respectively at fluidization velocities of 15.9 m/s, 21.21 m/s, and 25.61 m/s. Through photos and videos obtained during the drying process, it is seen that when the coal bed has been fluidized there will be no coal found in the middle area of the drying chamber.
| Item Type: | Thesis (Undergraduate) |
|---|---|
| Uncontrolled Keywords: | : Swirling fluidized bed, Coal dryer, 75%; 100%; dan 125% Kecepatan minimum fluidisasi, Tanpa pengarah aliran berbentuk cone. |
| Subjects: | T Technology > TJ Mechanical engineering and machinery > TJ164 Power plants--Design and construction |
| Divisions: | Faculty of Industrial Technology > Mechanical Engineering |
| Depositing User: | Alim Jabbar Ibrahim |
| Date Deposited: | 28 Apr 2021 06:03 |
| Last Modified: | 28 Apr 2021 06:04 |
| URI: | http://repository.its.ac.id/id/eprint/44630 |
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