INTRODUCTION:
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.
EMISSION
CONSIDERATIONS:
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:
- The
Trans-esterification process.
- Program was developed
using Visual Basic for caring out all the performance and volumetric test.
- Engine modification
for EGR was made.
- 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.
- 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
PROJECT OBJECTIVES
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 /
litre.
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 50°C - 60°C. If the temperature
exceeds beyond this limit the oil could catch fire since methanol ignites at
very low temperature.
Trans-Esterification Process
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)
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:
- Effective cooling has to be enforced for good
performance of EGR since gas at 500-600°C can’t be let into engine.
- Effective throttling has to be maintained so as to allow
required gas inside the cylinder.
- The exhaust has to be modified and the following
condition has to be acquired, so as to use the AVL 437C Smoke meter.
- The temperature at the position of measurement should
be maintained between 200 - 250°C
- The pressure at the position of measurement should be
maintained between 60-75mm of manometer.
- Exhaust gas should be taken at an angle of 135° so as
to have accurate readings.
TEST PROCEDURE:
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 WITH EGR:
From the above results, it
is the following can be interpreted:
·
The mechanical efficiency was better with Biodiesel with the
increase in EGR and also with the increase in the percentage of Biodiesel.
·
The specific fuel consumption of Biodiesel and the petroleum
diesel reduced with the EGR both in 50% and as well as in 100% EGR.
·
The brake thermal efficiency was best for the 50% EGR and
very similar to the brake thermal efficiency of the HSD.
COMPARISON FOR EMISSION
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
CONCLUSION
From the above results the
following can be interpreted:
- 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.
- No considerable change in the value of the torque was
noticed. The torque remained almost the same for all the blends
irrespective of EGR.
- Other performance
characteristics of the diesel engine running with Biodiesel almost
remained same with the implementation of EGR.
- The emission of NOX came down drastically. The emission was
reduced to 0.5% of original emission using Biodiesel and with petroleum
diesel.
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