The potential for Biodiesel availability is limited to roughly 2% of the current diesel fuel consumption. The present cost of Biodiesel is 2 to 3 times higher than diesel. Higher taxes on diesel fuel or tax incentives for Biodiesel, to eliminate this price differential, do not seem feasible at this time. Hence Biodiesel must find uses in markets where its positive attributes may support its higher cost and preferable in the form of lower level blends in diesel in ordered to minimize the incremental cost.
Besides the monetary incentives, the government policy and regulations can also help a fuel to find markets. If the federal and provincial governments in India impose stringent emissions regulations in underground mines, marinas, and other environmentally sensitive areas, it would certainly help Biodiesel to enter these markets even at its current higher cost efforts should be made to include Biodiesel as an alternative fuel under the Indian Alternative Fuels Act.
PROBLEM IN USING RAW JATROPHA OIL IN DIESEL ENGINES:
1. Due to higher density of Jatropha oil, the atomization in combustion becomes difficult.
2. Poor volatility accounts for improper vaporization and ignition incapability. This also cause thermal cracking resulting in heavy smoke emissions and carbon deposits in the engine.
3. The presence of wax contents in the oil causes formation of gum in the combustion chamber
4. Increased in emission of NOx with jatropha oil.
The emission results with the Biodiesel was satisfactory for CO, CO2, and SO. NOx is one of the main contributors to smog and acid rain. Burning fossil fuels again produces them. Nitrogen oxides react to form smog. Smog is high dose harms humans by causing breathing difficulty for asthmatics, coughs n children and general illness of the respiratory system. Since NOx causes these kinds of problems, to reduce it the EGR was implemented in the diesel engine.
OUR PART IN THIS PROBLEM:
Â¢ The Trans-esterification process.
Â¢ Program was developed using Visual Basic for caring out all the performance and volumetric test.
Â¢ Engine modification for EGR was made.
Â¢ The performance tests and the heat balance tests have been carried out to compare the various blends and their performance with each other with was carried out for the following
o Without any engine modification.
o With implementation of EGR.
Â¢ A comparison study between the performance of the various blends and the emission with EGR and without EGR is also presented.
Comparative performance of diesel engine was conducted using:
1. Diesel oil (HSD)
2. Blends of HSD and Bio diesel from Jatropha curcas (25% BD, 50% BD,75%BD)
3. Hundred percent bio diesel
The project was carried out in four major steps which include the transesterification of the jatropha oil, formulation of program using Visual Basic for performance test, modification of engine with EGR and conducting various tests using various blends of Biodiesel.
PURCHASING OF JATROPHA OIL
The raw oil was purchased from Rural Action Community Action Center (RCAC), Muthur. The main plantation was located at Kanisolai, maatukadai, kudumudi road, muthur.10 litters of raw jatropha oil were bought from this plant. RCAC has official agreement with Indian railways, thus oil was sold to us unofficial at a cost of Rs.80 / litter.
TRANS - ESTERIFICATION PROCESS
The trans-etherification process is carried out in order to reduce the viscosity of the oil by removing the fatty acid present in it.100ml mixture of NAOH and methanol is take in a burette and added to the raw jatropha oil with a constant interval of 30min. during addition of the mixture the temperature should be maintained between 50Ã‚Â°C - 60Ã‚Â°C. If the temperature exceeds beyond this limit the oil could catch fire since methanol ignites at very low temperature.
When all the mixture of methanol and NAOH is added to the raw jatropha oil it is allowed to settle in the container for 10hrs. After this there will clear separation on glycerol and the ester which is the required oil (Biodiesel)
Electrical Centrifuge for Separating Oil and Glycerol
The final test which proves that the oil is undergone good Trans - esterification is by its golden colour formation and the smell which should not have any occurrence of the alcohol used in process. The picture below shows the difference between raw jatropha oil and trans- esterified oil.
FABRICATION OF EGR
External EGR, using piping to route the exhaust gas to the intake system where it is inducted into the succeeding cycles, has emerged as the preferred current approach. This methodology was followed in our project.
The engine exhaust and intake manifold was modified so as to enhance the EGR set. The constraints involved in the fabrication of EGR are as follows:
Â¢ Effective cooling has to be enforced for good performance of EGR since gas at 500-600Ã‚Â°C canâ„¢t be let into engine.
Â¢ Effective throttling has to be maintained so as to allow required gas inside the cylinder.
Â¢ The exhaust has to be modified and the following condition has to be acquired, so as to use the AVL 437C Smoke meter.
o The temperature at the position of measurement should be maintained between 200 - 250Ã‚Â°C
o The pressure at the position of measurement should be maintained between 60-75mm of manometer.
o Exhaust gas should be taken at an angle of 135Ã‚Â° so as to have accurate readings.
1. The room temperature was noted down first.
2. Required quantities of blends were prepared according to their ratios by volume.
3. The fuel in the fuel tank, the supply of cooling water, level of lubricant in the sump as indicated by the dipstick and no load on the engine were checked before starting the engine.
4. The engine was started and allowed to run at no load for about 10 minutes to warm up and attain steady state. The speed of the engine was measured using a tachometer and it was adjusted to the rated speed of 1500 rpm by adjusting the governor connected to the fuel pump.
5. The fuel was then supplied from the burette by opening the metering valve. By noting the change in level of fuel in the burette, the time taken for 10cc of fuel consumption was noted using a stop watch.
6. The desired cooling water flow rate was obtained by adjusting the valve and was kept constant throughout the experiment.
7. The inlet and outlet temperatures of the cooling water are noted. The temperature of the exhaust gas was noted.
8. The full load of the engine was distributing equally so as to run at least five trials during the test from zero load (0 amps) to full load (12 amps). The set up readings were taken and tabulated.
9. The emissions are measured using the Flue gas analyzer, AVL 437C Smoke meter for all the combinations of biodiesel with HSD.
10. The manometer readings are also noted.
11. All the above readings were taken for various loads with applying and without applying EGR.
Electrical loading arrangement was used for loading the engine. All parameters relating to the engine performance were observed from the reading. Such parameter as,
1. Brake power
2. Fuel consumption rate, Specific fuel consumption
3. Fuel power
4. Brake thermal efficiency, indicated thermal efficiency
5. Brake and indicated mean effective pressure.
After, the experimental part of the project was completed, the calculations were carried out and various graphs were drawn so as to discuss and arrive at specified result. From the analysis of graphs the conclusion were made.
COMPARISON GRAPHS-WITH EGR:
BP VS MECH EFF FOR 100% EGR BP VS MECH EFF FOR 50% EGR
From the above results, it is the following can be interpreted:
Â¢ The mechanical efficiency was better with Biodiesel with the increase in EGR and also with the increase in the percentage of Biodiesel.
Â¢ The specific fuel consumption of Biodiesel and the petroleum diesel reduced with the EGR both in 50% and as well as in 100% EGR.
Â¢ The brake thermal efficiency was best for the 50% EGR and very similar to the brake thermal efficiency of the HSD.
COMPARISON GRAPHS FOR EMISSION
NOX EMISSION GRAPH FOR 50%HSD 50%BD NOX EMISSION GRAPH FOR 100%BD
The emission of NOX got reduced drastically with implementation of EGR. The above graphs clearly state the reduction of NOX.
The emission of CO got reduced drastically with Biodiesel.With the implementation of EGR the emissions of Biodiesel almost remained same and but the NOX emission got reduced drastically which was the only disadvantage faced in the implementation of Biodiesel. The emission of NOX reduced to 0.05%.
During full throttle of EGR and with full load the engine struggled to run using petroleum diesel and which made to stop the engine. But with 100% Biodiesel the engine ran without any trouble
From the above results the following can be interpreted:
Â¢ The mechanical efficiency of the engine while using Biodiesel is more than the conventional petroleum diesel. When the percentage of Biodiesel increases the mechanical efficiency also increases simultaneously. With EGR, the mechanical efficiency is maximum.
Â¢ No considerable change in the value of the torque was noticed. The torque remained almost the same for all the blends irrespective of EGR.
Â¢ Other performance characteristics of the diesel engine running with Biodiesel almost remained same with the implementation of EGR.
Â¢ The emission of NOX came down drastically. The emission was reduced to 0.5% of original emission using Biodiesel and with petroleum diesel.