Biogas digestate as a cooking fuel | |
| Author | Swamy, Kondamuri V V Satyanarayana |
| Call Number | AIT RSPR no.ET-18-08 |
| Subject(s) | Biogas Fuel |
| Note | A research study submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Energy |
| Publisher | Asian Institute of Technology |
| Series Statement | |
| Abstract | Biogas digestate is a by product of anaerobic digestion after biogas is produced. Digestate is the remaining solids of the original input material to the reactor that microbes cannot use them.Volume of digestate will be around 90-95% of feed inlet to the reactor. In this study the biogas digestate was collected from a pilot scale food waste based anaerobic digester of CSTR reactor from AIT. The biogas digestate is then dewatered to separate the solid and liquid portions and then, the solid content of the digestate should dried to reduce the moisture content in it. A solar air dryer is used for drying the solid digestate in this study, where more than 90% of moisture content was dried within 8 to 10 days depending on the solar radiation on the solar collector. The compositional characteristics of dried biogas digestate along with sawdust are analyzed, and the average values of the dried biogas digestate sample has calorific value of 21.35MJ/kg, proximate analysis results with moisture content of 9.61%, volatile matter of 68.93%, fixed carbon of 6.78% and ash content of 14.67%. Whereas sawdust sample has calorific value of 18.6MJ/kg, proximate analysis results with moisture content of 9.47%, volatile matter of 75.3%, fixed carbon of 14.8% and ash content of 0.42% respectively. Sawdust was selected as a binder material to the dried biogas digestate material and identified eight different binder ratios of samples such as 1:0, 3:1, 2:1, 3:2, 1:1, 2:3, 1:2 and 0:1 on weight basis and their physical and compositional characteristics are determined by using cold densification system in this study.At first, the maximum applicable pressures for all the eight different binder ratios of pellets are determined by preparing three samples for each binder ratio and the average values are, for the ratio 1:0 it is 1800 psi, 3:1 it is 2400 psi, 2:1 it is 2600 psi, 3:2 it is 2800 psi, 1:1 it is 3200 psi, 2:3 it is 3500 psi, 1:2 it is 3800 psi and for 0:1 it is more than 5000 psi. The characteristics such as density ratio, shatter index, compaction ratio, % elongation, % of volume change and proximate analysis and higher heating values were calculated and observed before and after 24 hours interval of time and noted that pellet prepared at 1:0 ratio at 1800psi has zero density and zero shatter index respectively. Secondly, to characterize and to select the best quality of pellets from the remaining seven binder ratios, all the pellets were prepared at a pressure of 2400 psi and characterized. From the results, the pellets at binder ratio 1:2 which has maximum pressure of 3800 psi was selected as a best quality from its characteristics by weighted average scoring method. Finally, the selected binder ratio (1:2 ratio) of pellets was prepared for an amount of 500 grams to check the fuel suitability along with sawdust pellets (0:1 ratio) which were also prepared for the same amount and were tested in a gasifier stove by conducting local water boiling test. From the results, the maximum water boiling temperature obtained for the digestate pellets (1:2 ratio) is 97°C temperature at time interval of 26 minutes and highest flame temperature obtained is 918°C temperature and the flame is continuously maintained up to 43 minutes time interval and fuel burning rate is 5.53 minutes and the stove efficiency has 55.03% respectively. Whereas the sawdust pellets (0:1 ratio) has the maximum water boiling temperature at 99°C temperature at time interval of 22 minutes and highest flame temperature obtained is 880°C temperature and the flame is continuously maintained up to 36 minutes time interval and fuel burning rate is 6.75 minutes and the stove efficiency has 67.59% respectively. |
| Year | 2018 |
| Corresponding Series Added Entry | |
| Type | Research Study Project Report (RSPR) |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Energy and Climate Change (Former title: Department of Energy, Environment, and Climate Change (DEECC)) |
| Academic Program/FoS | Energy Technology (ET) |
| Chairperson(s) | Salam, P. Abdul |
| Examination Committee(s) | Singh, Jai Govind;Kumar, Sivanappan |
| Scholarship Donor(s) | Asian Institute of Technology Fellowship |
| Degree | Research Studies Project Report (M. Eng.) - Asian Institute of Technology, 2018 |