| Author | Kittichai Banjong |
| Call Number | AIT Diss. no.AE-90-04 |
| Subject(s) | Grain--Drying
|
| Note | A dissertation submitted in partial fulfillment of the requirements for the degree of Doctoral Technical Science, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Dissertation ; no. AE-90-04 |
| Abstract | This study describes a new approach for analyzing thin—layer drying of rough rice based on transient air conditions. The grain bed was visualized to be consisting of several thin—layers stacked upon each other. The temperature and relative humidity of drying air changed continuously during its passage through various layers. An experimental multi—layer drying set—up complete with an air conditioning unit was specifically designed and constructed to produce fixed input air conditions at the bottom layer and transient air conditions in between the upper layers. The air conditions and moisture content of grain were continuously recorded by' a data logger and the microcomputer. Fixed inlet drying air conditions used in various tests were temperature ranging from 35 to 55 OC, relative humidity ranging from 17 to 70 % and air velocity of about 0-2 m/s. Initial moisture content of medium grain rough rice (RD23 variety) ranged from 18 to 30 % wb. The experimental drying data were analyzed by taking the instantaneous moisture content of grain in form of moisture ratio as dependent variable and the average values of air temperature and relative humidity, initial moisture content and time as in— dependent variables. The thin—layer drying equations developed on the basis of both fixed and transient input air conditions were found to be reasonably accurate in predicting the moisture content in various grain layers almost in an identical manner and could be used interchangeably. A procedure for the direct estimation of grain moisture at any location in deep bed drying using thin-layer drying equations based on continuous monitoring of air temperature and relative humidity histories was successfully developed. A computer program for drying simulation of rough rice drying in deep beds was also written following the conventional approach. A comparison of experimental moisture gradients in beds of rough rice with predictions based on conventional and newly developed approach revealed that the transient analysis led to similar results, and thus could be applied for interactive control of drying operation. |
| Year | 1990 |
| Corresponding Series Added Entry | Asian Institute of Technology. Dissertation ; no. AE-90-04 |
| Type | Dissertation |
| School | School of Environment, Resources, and Development (SERD) |
| 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, V. K.; |
| Examination Committee(s) | Athapol Noomhorm;Ilangantileke, S. G.;Prida Wibulswas; |
| Scholarship Donor(s) | Government of Australia; |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 1990 |