| Author | Islam, Md. Nurul |
| Call Number | AIT Thesis no.AE-79-15 |
| Subject(s) | Grain--Drying
|
| Note | A thesis submitted in partial fulfillment of the requirement for the degree of Master of Engineering, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Abstract | A controlled temperature laboratory type dryer was equipped with a specially designed humidifier and a preheater unit to control the drying air temperature and relative humidity. The whole unit was operated successfully within the temperature and relative humidity ranges of 80
1400F and 25 - 95 percent, respectively. It was possible to control the temperature of the drying air temperature by using the automatic temperature
controller. The relative humidity was controlled by limiting the water supply and the number of wetted baffles in the humidifier unit. The airflow was controlled by using a damper at the inlet opening of the blower. A series of thin layer drying tests were performed to investigate the
effect of drying air temperature , relative humidity, initial moisture content and the airflow rate by selecting various combinations of drying parameters. It was observed that the remoistened paddy dried up faster than
that of fresh paddy. The airflow rate and the initial moisture content had very little effect on the drying rate. However, the drying air temperature and the relative humidity were appeared to be affecting the drying rate most significantly. The semi-logarithmic plots of moisture ratio versus drying time exhibited nonlinear trends in all cases. A second degree polynomial equation was fitted
into the experimental data to represent the drying behavior.
The parameters of the developed thin layer drying equation were related to the air temperature, relative humidity and the initial moisture content through the step- wise multiple r egression analysis. A simulation model was developed to predict the drying in a deep bed of paddy consisting of a number of thin layers stacked upon each other. The experimental results from the multilayer drying tests were compared against the simulated results based on the model. The predicted drying rates were found to be higher than the experimental drying rates. The
experimentally observed and the predicted air temperatures in between the layers of the deep bed differed markedly. This possibly led to the higher drying rates computed in simulation model. |
| Year | 1979 |
| Type | Thesis |
| School | School of Environment, Resources, and Development |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Agricultural and Food Engineering (AE) |
| Chairperson(s) | Jindal, Vinod Kumar |
| Examination Committee(s) | Singh, Gajendra ;Exell, Robert H.B. ; |
| Scholarship Donor(s) | The Royal Norwegian Government |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1979 |