Continuous downdraft rice husk gasifier for paddy drying | |
| Author | Charoonsak Somphong |
| Call Number | AIT Thesis no.FB-09-05 |
| Subject(s) | Biomass gasification Agricultural wastes as fuel Biomass energy Crop residues--Utilization |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Food Engineering and Bioprocess Technology, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. no. FB-09-05 |
| Abstract | A continuous down draft rice husk gasifier was designed, constructed and tested to evaluate the performance characteristics. Tests were carried out to study the continuous downdraft rice husk gasifier. The test of gasifier were conducted by varying air supply rate 2.82¬4.2 kg/hr, rice husk feed rate 6.46-10.11 kg/hr and char thickness 10-70 cm Producer gas was checked and the optimum condition of gasifier was used as heat source for paddy drying using rotary dryer. Quality parameters of milled rice were used to describe the convection drying process of paddy. Then mathematical drying models were used to describe the characteristic of drying process. Continuous Down draft rice husk gasification was achieved at air supply rate 2.82 kg/hr, rice husk feed rate 6.46 kg/hr and 30-50 cm char thickness with 42.34 % gasification efficiency. In addition, this operating condition of gasifier produced 39.10 MJ of heat per hour with air fuel ratio 0.038 kg/kg and specific gas production rate 195.68 m³/ (hr. m²). The output heat was applied in rotary dryer to create three different temperature; 60-80, 80-100 and 100-120 °C. The optimum drying temperature was 60-80 °C. Drying of paddy with hot air temperature between 60-80 °C had improved milling yield when compared with shade dried reference paddy. The milling yield of the shade dried was about 35 % where as the maximum yield of hot air dried sample was 44.050 % after drying for 15 minutes moisture content was 18.22 % MCwb then tempering for 2 hour and shade dried until final moisture about 14 % MCwb. In addition, the whiteness, yellowness and white belly value of paddy dried at 60¬80 was 40.73, 17.81 and 12.60, respectively. To maintain good head rice yield, it is recommended that high moist paddy should be dried to about 18 % MCwb then tempering for 2 hours before shade drying until final moisture about 14 % MCwb Modified Page model gave excellent fitting to the paddy drying by using rice husk gasifier as heat source for all case. Modified Page model was the best one to predict the moisture of paddy at temperature 60-80 °C with value of coefficient of determination or R² (0.995), chi-square or x² (6.198 x 10⁻⁵) and root mean square error or RMSE (0.0071). |
| Year | 2009 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. no. FB-09-05 |
| Type | Thesis |
| 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 | Food Engineering and Bioprocess Technology (FB) |
| Chairperson(s) | Athapol Noomhorm; |
| Examination Committee(s) | Rakshit, Sudip Kumar;Salokhe, Vilas M.; |
| Scholarship Donor(s) | RTG Fellowship; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2009 |