الفهرس 
Biogas SystemOnly 14 pages are availabe for public view
 |  | from | 123 |  |  |
| | | from | 123 | | |
Abstract
Egypt facing a lot of problems among these problems farm wastes disposal such as rice straw, the amount rice straw was estimated to be 3.5±0.6 Mt per year. Assuming that about 20% were used for other purposes about 2.8 Mt were left on the fields for burning within a period of 30 days to get quickly rid of leftover debris. The resulting emissions give a significant contribution to the air pollution called the “Black Cloud. Another problem is leaving the organic fertilizer on open field which reduce its content of nitrogen, also we face energy crisis is many forms such as gasoline and propane problems from time to time also electricity.
Producing biogas from farm wastes can solve the fertilizer and farm waste problems while using biogas as a fuel to run internal combustion engine to power electricity generator will help in solving the energy problem.
Methodology:-
This experiment were conducted on three stages,
a- The first stage aim to test the ability of using rice straw to produce biogas and determine the prober mixing ratio (rice straw: cow slurry) and also to study the effect of thermal insulation of the digesters on biogas.
Eight small size digesters divided into two groups every group four digesters, the first group coated with black color to absorb solar heat, the second group thermally insulated and both groups contain three treatments (control – 15% Rice Straw – 30% Rice Straw - 45% Rice Straw) where the percentage imply to rice straw content to Cattle Dung in dry mass base
b- The second stage aimed to produce biogas from medium on-field digesters to verify the first stage results and produce more biogas to conduct the handling process on biogas and obtain enough biogas to the third stage, also evaluate purifying process for biogas and evaluate this process.
c- The third stage internal combustion engine (diesel engine) coupled with electricity generator, a mixing tool designed to control air biogas mixture to the engine to convert the engine to run in dual mode, engine and generator characteristics studies in the conventional mode and compared with dual mode, environmental issue was studied such as CO concentration on exhaust gas and how much fuel can be saved in this process, the main results can be summarized in the following points:
1- Biogas production from black covered digesters was more than thermal insulated digesters.
2- The optimum mixing ratio to rice straw with cattle dung was 30% rice from total solid content.
3- The average production rate in thermal insulated digesters were (0.22- 0.26- 0.45- 0.42) l/kg.day for (control- 15% - 30% - 45%)
4- The average production rate in black covered digesters were (0.30-0.33- 0.48- 0.44) l/kg.day for (control- 15% - 30% - 45%) 5- The specific diesel consumption decreased by 40% when running in dual mode.
6- 40% of diesel fuel can be saved by using biogas as a fuel in dual mode.
7- Engine efficiencies (thermal and volumetric) decreases by (28% and 11%) respectively when running on dual mode. Exhaust gas contain more CO emissions by 18% when running on dual mode.