ANALISIS MATEMATIS PROSES PENGERINGAN MEKANIS JAGUNG TONGKOL DALAM KARUNG DENGAN VARIASI SUHU DAN LAJU ALIRAN UDARA PENGERING

MARIETA DYAH R, Dr. Ir. Nursigit Bintoro, M.Sc. ; Hanim Zuhrotul A., STP., MP.

2014 | Skripsi | TEKNIK PERTANIAN

Pengeringan jagung masih dilakukan dengan sinar matahari karena pengeringan ini lebih murah dibandingkan dengan pengeringan secara mekanis. Berdasarkan alasan tersebut, perlu dibuat pengering mekanis yang terjangkau. Pada penelitian ini jagung tongkol dikeringkan dalam karung. Proses pengeringan jagung tongkol menggunakan aliran udara panas yang dihembuskan dengan bantuan blower. Tujuan penelitian ini adalah untuk menentukan nilai konstanta laju pengeringan (k), nilai koefisien perpindahan panas secara konveksi (h) dan daya kecambah biji jagung. Jagung tongkol dikeringkan dengan variasi suhu 50oC, 60oC, 65oC, 70oC, 75oC, 80oC, 90oC, 95oC dan 100oC dan variasi laju aliran udara 0.0684 m3/s, 0.0456 m3/s dan 0.0228 m3/s. Pengeringan jagung tongkol dilakukan dari kadar air 21% - 24% hingga kadar air aman untuk dipipil yaitu sekitar 18%. Data diambil setiap 30 menit. Data yang diambil meliputi kadar air, suhu, dan RH. Dari penelitian ini, nilai konstanta laju pengeringan berkisar antara 0.017%/menit - 0.066 %/menit. Koefisien perpindahan panas konveksi berkisar antara 1.4177 W/m2.oC - 2.9804 W/m2.oC. Daya kecambah biji jagung berkisar 12% - 80%. Hasil penelitian menunjukkan semakin tinggi suhu udara pengering maka laju penurunan kadar air bahan dan laju kenaikan suhu jagung akan semakin besar. Selain itu, nilai HUF kecil dan COP besar. Hal ini berarti panas yang dimanfaatkan dalam proses pengeringan kecil dan semakin banyak panas yang terbuang.

Drying of corn are still done using the sun because there are cheaper compared to mechanical drying. Based on these reason, it is necessary to make affordable mechanical dryer. In this research, corn cobs were dried in the sack. Corn cobs drying process was used hot air stream which were blown with the help of a blower. The purpose of this research was to determine the drying rate constant (k), the value of convective heat transfer (h), and corn seed germination. Corn cobs were dried at varied temperature of 50oC, 60oC, 65oC, 70oC, 75oC, 80oC, 90oC, 95oC and 100oC and varied air flow rate of 0.0684 m3/s, 0.0456 m3/s and 0.0228 m3/s. The water content of corn cobs were reduced from 21% - 24% until water content was about 18% or safe to be shelled. In the process of drying, datas were taken every 30 minutes. The datas were water content, temperature and RH. From this research, the value of drying rate constant is 0.017%/min - 0.066 %/min. The value of convective heat transfer is 1.4177 W/m2.oC - 2.9804 W/m2.oC. The corn seed germination is about 12% - 80%. The result showed that the higher the drying temperature, the bigger the rate of decrease in moisture content and the rate of temperature rise in corn. Besides that, the value of HUF is small and the value of COP is big. It means that a small amounts of heat are used in the drying process and more heat are wasted.

Kata Kunci : jagung tongkol, pengeringan, kadar air, suhu, laju aliran udara, corn cobs, drying, water content, temperature, air flow rate