CONSTRUCTION AND TESTING ROUGH RICE SWIRLING FLUIDIZED BED DRYER FOR LABORATORY SCALE

• Main Author: Novrinaldi
• Format: Theses
• Language: Indonesia
• Subjects: Teknik (Rekayasa, enjinering dan kegiatan berkaitan)
• Online Access: https://digilib.itb.ac.id/gdl/view/41942
• Institution: Institut Teknologi Bandung

Grain has been an important agricultural commodity and primary food source for centuries. The present distribution of the world’s population has made strong demands on grain-handling technology. One of the problem post-harvest is a storage. One of the quality standards of grains for storage is moisture content, reducing the water content by drying to maintain the quality of grains. The widely used drying technology for granular materials at the moment is the fluidization drying technology. In this study was carried out the construction and testing rough rice swirling fluidized bed dryer for laboratory scale. The initial stages of the research were literature studies on fluidization dryers in general and focused swirling fluidized bed dryer and followed by preparing the design. The next stage is the construction process of all parts of the dryer which consists of drying chamber (column), plenum chamber, annular blade distributor, centre body, air duct, and space for fin heater. Air fluid source using two blowers with first blower 1 2200 watt power , 2900 rpm, 2000 m3/h air capacity, 2.96 kpa static pressure and 380 v voltage and second blower power specification 1000 watt power, 2800 rpm, 1512 m3/h air capacity, 1.76 kpa static pressure, 220/50 hz voltage and maximum temperatur 160-200 oC and. Fin heater used as much as 5 units with 1000 watt per unit heater. Testing is done empty load and with load variation. From the test result without load the fluid velocity above the annular blade distributor on the column wall has reached the minimum fluidization so that fluidization will occur. The lowest speed is 8.04 m/s and the highest is 11.51 m/s. The speed at the center body is low relatively,that is 5.6 m/s, 6.2 m/s, 6.4 m/s, 5.4 m/s and 6.7 m/s while the minimum fluidization to be achieved is 6.89 m/s. The test with drying load of rough rice was done with four variations of load that is 150 gr, 200 gr, 250 gr and 300 gr. The decrease of rough rice water content is relatively uniform in the four variations that is the decrease of significant water content in the first 10 minutes of drying where the water content is still high. During the drying process the rough rice water content decrease 27.06% to 12.06%, 29.25% to 14.03% and 28.58% to 14.21%. The relative humidity decreases as a result of the rise in drying temperature. Changes in drying air temperature are strongly influenced by the moisture content of the material to be dried. In the loadless test and the test with variation of drying capacity, the same pressure was obtained on the inlet air to the plenum chamber and under the distributor. With different blower specifications the measured pressure on the inlet and under the distributor is also different. Inlet 1 of the blower with a power of 2.2 kW produces a pressure of 74 mmH2O or 0.725693 kPa and inlet 2 produces a pressure of 50 mmH2O or 0.490333 kPa of a 1 kW blower. Pressure under the distributor at point "G" -10 mmH2O and 20 mmH2O at point "C". Convection heat transfer that occurs each -1002.84 Watt for drying capacity 150 gr, -1339.84 Watt for drying capacity 200 gr, for drying capacity 250 grams of heat moving from air to rough rice of -1571.33 Watt and -2082.06 Watt for 300 gr drying capacity. The minus sign indicates heat is moving from air to grain because the grain temperature is less than the dryer air temperature (Ts <Tu). The amount of water that has been evaporated is 24.82 gr for drying capacity 150 gr, 35.41 gr for capacity 200 gr, 41.88 gr for capacity 250 gr and 45.3 gr for capacity 300 gr. The amount of water vapor in the air for each drying capacity after 60 minutes of drying is 5.81 gr / kg, 7.56 gr / kg, 5.23 gr / kg and 6.95 gr / kg.for drying capacity 150 gr, 200 gr, 250 gr and 300 gr. The amount of heat energy required to heat the rough rice in each drying capacity variation is 6.12 kJ, 8.16 kJ, 10.19 kJ and 12.23 kJ while the amount of heat required to evaporate water from the rough rice for capacity 150 gr, 200 gr, 250 gr and 300 gr is 59.43 kJ, 84.79 kJ, 100.28 kJ and 108.49 kJ.