Conclusions and Future Scopes
10.4 Future Scopes
The present investigation focuses the prospect of emulsified biodiesel in a variable compression ratio diesel engine. In order to examine the performance of emulsified biodiesel, the original biodiesel is also tested in similar operating specifications. Thereafter, the first and second law analyses are performed at full load condition for both type of fuels and discussed subsequently, in the sections above. However, there are also several scopes for future study, related to this field, which can further enrich the area of alternative fuel. These are listed below.
The gaseous fuels generally used in dual fuel engine have higher auto ignition temperature and hence high ID. The ID of liquid pilot fuel is again affected. As a result, a much higher ID in dual fuel mode causes the PCP to reduce by shifting it towards the expansion stroke. This cuts the BTHE of the dual fuel engine than diesel engine.
However, the study performed here showed that, WIP (water emulsion of POME) produces almost equivalent power with lower consumption then diesel. Further, it results lower ID and moderate emission values. The use of WIP provided far more improved engine performance than POME as a fuel. Therefore, this work can further be extended by using WIP as a pilot liquid fuel, along with various other gaseous fuels (CNG, LPG, etc.) in dual fuel diesel engine.
In this work, only one biodiesel type (palm oil origin) is used for the possible application as an emulsified alternative fuel in diesel engine. However, various locally available biodiesel types can be emulsified and checked by running in diesel engine along with detailed life cycle analysis (LCA). These may include biodiesel produced from rice husk oil, jatropha oil, sunflower oil, rubber seed oil, peanut oil, coconut oil, karanja oil, honge oil etc. Further improvement in engine performance and emission by using biodiesel
produced from any of these oils can open huge scopes for government and related organizations in rural employment, which will boost the economy of the nation itself.
Now a days, applications of nano-fuels are becoming popular. This is nothing but the addition of nanoparticles (namely, griffin, carbon nanotube, etc.) in normal liquid fuel.
Addition of these nano particles increases surface area of heat dissipations. This increases the quicker heat transfers, even at the most remote locations of heterogeneous fuel air mixture in diesel engine. Consequently, combustion become faster with reduced ignition delay and lower fuel intake. However, till date almost all of the nano-fuels used to run diesel engine are diesel based. The technology can also be implemented for renewable fuels, such as, biodiesel.
In this study, ultrasonic bath emulsifier is used to prepare the emulsion. This produces ultrasonic wave from the surrounding walls. However, the production of biodiesel emulsion has not been explored with tip sonicator, which produces ultrasonic waves from a tip placed at the centre of the solution. The stability study performed in this work for emulsified POME can be extended further. The emulsified biodiesel can be checked for longer duration, say, several days or weeks to check the volumetric deposition, on the basis of its use. Although the volumetric depositions are checked minutely, however, the concentration of water droplets in emulsified fuels can be checked by ultraviolet spectrometer. This may offer more precise results of water deposition, with the change of time. Further, emulsion activity analysis can also be performed for biodiesel-based emulsion. This is done by centrifuging the emulsion at various speeds to check the droplet agglomeration due to the action of centrifugal force. This study is a key for the mobile use of emulsified fuel.
Preparation of emulsification needs the implementation of some extra energy in the form of ultrasonication. Needless to say that, an economic assessment of emulsified fuel run engine is necessary from the social viewpoint. A detailed cost analysis of the energy ingestion in the form of ultrasonication, cost of fuel, running cost, power generation, environmental aspects and other costs can be executed to see the profitability of the use of emulsified fuel. However, for the viewpoint of large-scale applications with implementation of renewable biodiesel as the carrying fluid of fuel emulsion that may cut the cost associated with its preparation. The alternative methods of emulsifications,
namely, gas in liquid emulsification or effervescent atomization can be tried to curb the cost associated with its preparation.
Thermodynamic modeling of emulsified fuel combustion is also lacking in the literature.
The micro-explosion of emulsified fuel and subsequently its combustion are two completely different phenomena. These two methods are occurring simultaneously during the combustion of water-emulsified biodiesel in diesel engine. There is no indigenous model available to replicate the combined phenomenon of micro-explosion and combustion. The assistance of zero, two or three-dimensional modeling can be implemented in varying load conditions, to know the effect of micro-explosion in the combustion temperature, ignition delay, heat release rate, combustion duration, etc. This will allow to optimize the rigorous experimentation, and will save a lot of time, effort and money.