M Ayub Hossain
Scientific Officer
Farm Machinery and Post harvest Process Engineering Division
Bangladesh Agricultural Research Institute
Gazipur-1701
Sultn Ahmmed
Senior Scientific Officer
Farm Machinery and Post harvest Process Engineering Division
Bangladesh Agricultural Research Institute
Gazipur-1701
K C Roy
Chief Scientific Officer
Farm Machinery and Post harvest Process Engineering Division
Bangladesh Agricultural Research Institute
Gazipur-1701
The existing biomass fuelled drier was modified to improve its performance. Circular air entry channel was changed to flat-elliptical shape for uniform distribution of air in the drying chamber. Blower pulley was fixed outside of the airflow channel. A metal cover was incorporated at the fresh air entry vents to control fire in the furnace and an adjustable air vent was incorporated at the entry of hot air channel to control the temperature of the hot. An experiment was conducted at FMP Engineering Division, BARI for drying of fresh maize ears. About 150 kg of maize ears with sheath and 20 kg of ears without sheath were dried with 60 mm bed thickness. Drying rate of maize ears without sheath was found to be higher that the maize ears with sheath. Moisture content of maize ears reduced from 40.31 to 11.67 and 14.36% (wb) respectively for ears without sheath and with sheath in 7 hours. Some problems were observed during drying of maize. Smoke and temperature fluctuations were observed just after feeding of rice husk. Fuel consumption was reduced from 4 to 3 kg/h. The drier may be tested for drying of different type of grain crops.
Biomass, dryer, furnace, maize. temperature
Postharvest and Agro-processing
1. To modify the design of the heating unit of the existing biomass operated mechanical drier
2. To test the performance of the drier for drying of maize, wheat and paddy etc.
The existing biomass drier at FMPE Division was developed for drying of grain crops utilizing agricultural waste. The main components of the drier were a furnace of cylindrical metal drum, a separator of similar metal drum, axial blower and flat bed drying chamber. There were some problems in the drier such as temperature could not be controlled during drying, smoke problem and fuel consumption was very high. To eliminate these problems the following modifications were done:
(i) Circular air entry channel was changed to flat-elliptical shape for uniform distribution of air in the drying chamber.
(ii) Blower pulley was set outside of the airflow channel to protect the belt from heat.
(iii) A metal cover was incorporated at the fresh air entry vents to control fire in the furnace.
(iv) Adjustable air vent was incorporated at the entry of hot air channel to control the temperature of the hot air to be entered in the drying chamber.
An experiment was conducted for drying of fresh maize ears. The fresh maize ears with sheath and without sheath were dried during April 2005. About 150 kg of maize ears with sheath and 20 kg of ears without sheath were loaded with 60 mm bed thickness. The initial moisture content of maize ears was about 40% (wb). The temperature and sample weight of were measured at front, middle and rear side of the drying chamber. Measured amount of rice husk was put in the furnace and fired. The heated air was collected from the furnace and passed through the grains in the drying chamber with the help of an electric blower. During drying, data of weight loss and temperature were measured at one hour interval. Drying was continued to reach the moisture content of the grain to safe moisture content.
Research Report
Air temperature in the drier was reasonably uniform but just after feeding of rice husk in the furnace, temperature went up high. Drying rate of maize ears without sheath was found to be higher than that the maize ears with sheath. Moisture content of maize ears reduced from 40.31 to 11.67 and 14.36% (wb) respectively for ears without sheath and with sheath in 7 hours. Fuel consumption was reduced from 4 to 3 kg/h.
Report/Proceedings