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Future of Automobile fuel series’ last leg
Summary of “fuel options”
In this article we will compare all the options we considered in the serial.
We should also consider other processes used in industry other than fermentation to produce alcohol using comparatively lesser amount of heat. In that process, first water gas is produced by heating carbonaceous material in reduced atmosphere up to 300 degrees Centigrade and the exuding flue gases are collected and under pressure passed over catalyst at high temperature. Heat generated during the production of water gas is used. By heating a mixture of CO and Hydrogen in the water gas under pressure in the presence of a catalyst (example, zinc chromite plus small amounts of alkali metal or iron salts). The mixture of Alcohols containing methyl, Ethyl, n-propyl, iso-butyl and higher branched alcohols is obtained; vapor of various alcohols is collected, cooled and stored. Individual alcohols being separated by fractional distillation in the next process. This is only a brief description of the process. Presently this process is in use at industrial level to produce alcohols of various types for industrial application. This process is far superior to the age old process of fermentation. It has been proved by the actual experience that the fermentation process is suitable only for production of potable alcohol. For all other applications this catalytic process is recommended. Strangely we see that in India only fermentation process is used to produce alcohol. This makes alcohol more expensive by many standards; such as economical, thermal and environmental. This argument suggests that in India we must ban the use of fermentation process for producing industrial alcohols and insist that industry uses biomass to produce alcohol, using this catalytic process. In one survey we found that quantity of biomass generated in a sugarcane farm is 30 percent of the actual sugarcane produced by weight. Quantity of molasses generated is almost same. Comparing these two by-products it is shown that economically and thermally converting biomass into alcohol is far superior to that of converting molasses into alcohol. In addition to that we also have one advantage of the catalytic process that is; no pollution is made while alcohol is produced. When fermentation process is used; large amount of pollution is made in the form of effluent waste water having very high B.O.D value. This waste water is a very big problem for distilleries and environment.
A comparative study was made in an American university and the results suggested that producing alcohol fuel from molasses is much costlier than producing fuel grade alcohol from buggass, a waste product of sugar industry. Heat generated was also used to produce electricity. It observed that the actual heat required to produce alcohol from water gas (producer gas mixture) is not much and so process units with combined production can be developed with advantages. The catalyst required is not very costly and is easily renewed. More research in this subject suggests that the green biomass that the farms generate is best converted in to a lignotite or cinder. That means first dry the green biomass in Sun to remove superficial water by simple evaporation and then bake it in kilns at 250 degrees Centigrade temperature to remove chemically fixed water in the biomass. At this, all the mass is converted into lignotite, a deep brown mass of carbonaceous material. This lignotite is the raw material for making producer-water gas which is finally converted in alcohol aggregates. When this alcohol mixture (aggregate) is used as fuel for vehicles no further processing is required on it. At present this process is used to produce volatile alcohols as solvents and also aromatic compounds. Technology involved is not very high tech. Skills required to manage these plants is also not very special. Investment required is also not very formidable. This clearly shows that this option is well within the capacity of Indian entrepreneurs.
So far we considered options using some sort of an engine to generate power to drive a vehicle; however recent developments are indicating that other methods can be used with an advantage to drive vehicles. Here we see that there are two basic ways practiced to drive a vehicle. In the first a fuel is burnt in the appropriate way to generate energy as thermal force and that force is then converted into a dynamic force which drives the vehicle. In the second way energy is not generated but ready energy is stored in some ingenious way and then it is made available to drive the vehicle. Battery operated electric vehicles, the very first option we considered, comes under this type. Recently we see that other methods to store energy are also used with some success. Here energy is stored in the form of high pressure. Compressed air or nitrogen gas is used in this method as a medium to store energy. A suitable cylinder is used to store gas in the compressed condition and when one operates a pneumatic motor using the compressed gas it drives the vehicle. This method is found to be very useful in some types of transports. Problem with this method is that the stored gas does not last long. As the gas is used up the vehicle stops. Or the gas is continuously replenished by changing the cylinders. A very large cylinder can withstand good distance of traverse. Experts have opined that this method of transport is suitable for closed type of transport systems only. On golf club, on airports to carry load of baggage, within a companies courtyard to transport personnel or goods, on tourist or fun centers for the pleasure of visitors such applications are recommended for this type of transport. Some are more optimistic. They suggest that this mode of transport can be used with an advantage if used to drive scooters or bicycles.
Readers of this articles may be perplexed to see why certain mode of transport is recommended for certain applications and how to decide this? There is a simple thumb rule that decides this. The thumb rule is weight of the engine and other required accessories and the weight that the engine can carry by using that mode of transport is used to make a ratio. For example, weight of engine and the accessories is taken as unit 1, with this assumption we take the weight that engine can carry is say 10 that means the ratio is 1:10. This ratio is best to carry many vehicles. In most of the petrol engines this ratio is some times better than 1:10. In diesel engines the ratio is sometimes same as this. As for steam engines this ration is much less than this and so steam engines were discarded long ago. Electrically driven and powered by battery are having ration 1:4. This is a very poor ratio and so this application is not recommended for big vehicles. Stored power as compressed gas has ratio similar to that of battery operated vehicles or less and so the suggestion is that this can be used for powering bicycles, scooters, and that also for city use only. Like battery operated vehicles where battery is charged at home using domestic power supply these vehicles also can be charged using a pump operated at home using domestic power supply. Some bicycles are designed so that they can be charged with compressed gas at any place where suitable power supply is available. Some readers will be confused at the explanation that steam engines have a very low ratio because they know that steam engines are used to power locomotives where this ratio is very large to the tune of 1:100. This is a case of apparent paradox. The steam locomotive is rolling on well formed rails and so the frictional resistance of the traction is very low and almost constant whereas vehicle running on roads this frictional resistance is very high and continuously varying.
Amongst all the options we considered Botryococcus alga and oils from it is the most suitable. It virtually mimics naturally available petroleum oil. However, there are some problems in accepting this option immediately. This technology is still under development and whatever techniques are available are not economically feasible at present.
Looking to this survey of available options to petroleum oils many experts have accepted that producing alcohol from green biomass using catalytic process is by far the most advantageous and economical and also environment friendly option. One estimate shows that if 40 percent of available green biomass in converted into producer gas and used to generate energy we shall generate 13 times energy that the world needs. Theoretically, total biomass available can produce vehicular power 20 times produced by mineral oils all over the world. These estimates pin point the reality that green biomass is the answer to our power problem. Collecting this biomass and utilizing it properly needs administrative skills which we already have developed. So where is the problem! The problem lies in, will to do all this seriously. Where there is no will there is no way, goes the saying.
Change over from petroleum oil to “alcohol aggregate” (alcofuel) has many ifs in it! Now we shall try to understand them.
Existing engines shall not deliver the same power from alcohol driven engines and so we shall have to modify the engines of our vehicles. New set of vehicles will be developed to work on this fuel. Even material used in making these next generation engines will be much different from what is used for conventional engines. Since alcohol has no detonating defect engines can be designed to take up only normal pressure developed during the combustion. That means stainless steel pipes can be used with cast iron lining as cylinder and aluminum alloy piston can be used with many advantages such as light weight, high strength and above all reduced cost of manufacture. Single cylinder with hydraulic driving system can replace present day multi cylinder heavy engines. Because there are no detonations in the combustion no excess heat is generated when the engine will work. This makes it possible to use thermosetting plastic parts in the engine such as sump and side panels. Designers are very optimistic about the many possibilities with this new fuel. Some critics however keep complaining about the initial investment that will go in the development of that engine. But that is not a very serious drawback in the proposal. These engines will look thirty percent larger but they will be also forty percent lighter! So this may compensate for the large size. Alcohol burns more slowly than petrol and so engines will be slow in speed. This is compensated by using a modified gear box and transmission.
Overall observation suggests that, this option of catalytic alcohol is the fuel for tomorrow.
Finally we shall see what our pyrotechnicians say. We know that an explosive releases tremendous energy when the explosion takes place. This energy can be stored in a hydraulic or pneumatic system and used to drive a vehicle. Simple example given in this regard is that of a gun. When a gun is fired the powder explodes releasing much energy in a very short time. This energy creates extreme pressure on the bullet and that pressure drives the bullet at very high speed. A model was designed by a French scientist in 18th century. In that the explosion created energy was stored in a pneumatic cylinder. On one side, explosions like machine-gun, were producing power which was stored in the strong big cylinder. This energy in the form of pressure was used to drive a pneumatic motor. That was first engine developed using explosives as fuel to create useful energy. That invention was lost in time as many worthy inventions have gone and forgotten. Now is the time to reconsider all these long forgotten inventions with renewed approach.
Amongst all the explosive materials acetylene gas is considered to be the most useful. This gas can be produced by dropping water on calcium carbide. Gas generated in this way is at present used in gas welding work. One retired aeronautic engineer had used this gas to run a scrap turbine engine from old bomber planes in India. The experiment was not continued further for no known reason but whatever was done showed to the observers that this gas can be used as a fuel for power generation plants and not for vehicles. Theoretically it is shown that part of the power generated using acetylene gas as fuel is used to convert lime and charcoal into calcium carbide and that carbide is used to generate acetylene gas to power the turbine in turn. This cycle of operation shall help develop a fully independent power generating unit. The only input will be charcoal; lime will be recycled. More research is required to finalize the design of such a power generating unit. Companies like Tata power, Larsen & toubro (L&T) in India and many bigger companies elsewhere should take up this subject. My purpose in preparing this study report on alternative fuels for vehicles as well as power generating units is to invite attention of deserving people to look into the subject. This report clearly shows that the problem of fuel is not as formidable as it is shown to be.
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