Biodiesel in India

Field trials of biodiesel: Indian Oil Corporation (IOC) began in January 2004, field trials of running buses on biodiesel – diesel doped with 5% BioDisesl made from non-edible oils. Haryana Roadways buses would be used for the project. About 450 kilolitres of bio-diesel would be used in the pilot project. Vehicles engine would not require any modification for use of bio-diesel. Already automobile manufacturers like Mahindra and Mahindra and Ashok Leyland have tried biodiesel mix as fuel for their vehicles. Meanwhile planning commission has asked states to grow more of Jatropha and Karanj on wasteland and semi rain fed areas.
The first successful trial run of the Amritsar-Shatabdi Express conducted by the Indian Railways using biodiesel has been an encouraging development.

1 Introduction: Biodiesel is methyl or ethyl ester of fatty acid made from virgin or used vegetable oils (both edible & non-edible) and animal fats. The main commodity sources for biodiesel in India can be non-edible oils obtained from plant species such as Jatropha Curcas (Ratanjyot), Pongamia Pinnata (Karanj), Calophyllum inophyllum (Nagchampa), Hevca brasiliensis (Rubber) etc. Biodiesel contains no petroleum, but it can be blended at any level with petroleum diesel to create a biodiesel blend or can be used in its pure form. Just like petroleum diesel, biodiesel operates in compression ignition (diesel) engine; which essentially require very little or no engine modifications because biodiesel has properties similar to petroleum diesel fuels. It can be stored just like the petroleum diesel fuel and hence does not require separate infrastructure. The use of biodiesel in conventional diesel engines results in substantial reduction of unburned hydrocarbons, carbon monoxide and particulate matters. Biodiesel is considered clean fuel since it has almost no sulphur, no aromatics and has about 10 % built-in oxygen, which helps it to burn fully. Its higher cetane number improves the ignition quality even when blended in the petroleum diesel.
New vehicles (except 2 and 3 wheelers) compliance of Bharat Stage II emission norms are to be enforced in the entire country from 1.4.2005 and Euro III equivalent norms by 1.4.2010. In addition to 4 metros where Bharat Stage II norms are already in place, Bangalore, Hyderabad, Ahmedabad, Pune, Surat, Kanpur and Agra should also meet this norm from 1.4.2003. The four metros and the other seven cities should comply with Euro III and Euro IV equivalent emission norms from 1.4.2005 and 1.4.2010 respectively. The 2 and 3 wheelers should conform to Bharat Stage II norms from 1.4.2005 all over the country and Bharat Stage III norms preferably from 1.4.2008 but not later than 2010. For new vehicles, a drastic reduction in sulphur content (< 350 ppm) and higher cetane number (>51) will be required in the petroleum diesel produced by Indian Refineries. Biodiesel meets these two important specifications and would help in improving the lubricity of low sulphur diesel. The present specification of flash point for petroleum diesel is 35°C which is lower than all the countries in the world (>55°C). Biodiesel will help in raising the flash point, a requirement of safety.
B20 (a blend of 20 percent by volume biodiesel with 80 percent by volume petroleum diesel) has demonstrated significant environmental benefits in US with a minimum increase in cost for fleet operations and other consumers. Biodiesel is registered as a fuel and fuel additive with the US Environmental Protection Agency and meets clean diesel standards established by the California Air Resources Board. Neat (100 percent) biodiesel has been designated as an alternative fuel by the Department of Energy and the Department of Transportation of US. Studies conducted with biodiesel on engines have shown substantial reduction in Particulate matter (25–50%). However, a marginal increase in NOx (1-6%) is also reported; but it can be taken care of either by optimization of engine parts or by using De-NOx catalyst (De-NOx catalyst will be necessary for Bharat-III / IV compliant engines). HC and CO emissions were also reported to be lower. Non-regulated emissions like PAH etc were also found to be lower.
Biodiesel has been accepted as clean alternative fuel by US and its production presently is about 100 million Gallons. Each State has passed specific bills to promote the use of biodiesel by reduction of taxes. Sunflower, rapeseed etc. is the raw material used in Europe whereas soya bean is used in USA. Thailand uses palm oil, Ireland uses frying oil and animal fats. Due to its favorable properties, biodiesel can be used as fuel for diesel engines (as either B5-a blend of 5% biodiesel in petroleum diesel fuel or B20 or B100).
USA uses B20 and B100 biodiesel. France uses B5 as mandatory in all diesel fuel. It can also be used as an additive to reduce the overall sulfur content of blend and to compensate for lubricity loss due to sulfur removal from diesel fuel. The viscosity of biodiesel is higher (1.9 to 6.0 cSt) and is reported to result into gum formation on injector, cylinder liner etc if used in neat form. However, blends of up to 20% should not give any problem. While an engine can be designed for 100% biodiesel use, the existing engines can use 20% biodiesel blend without any modification and reduction in torque output. In USA, 20% biodiesel blend is being used, while in European countries 5-15% blends have been adopted.

2 Biodiesel as an option for Energy Security: India ranks sixth in the world in terms of energy demand accounting for 3.5% of world commercial energy demand in 2001.The energy demand is expected to grow at 4.8%. A large part of India’s population, mostly in the rural areas, does not have access to it. At 479 kg of oil equivalent the per capita, energy consumption is very low. Hence a program for the development of energy from raw material which grows in the rural areas will go a long way in providing energy security to the rural people.
The growth in energy demand in all forms is expected to continue unabated owing to increasing urbanization, standard of living and expanding population with stabilization not before mid of the current century. The demand of Diesel (HSD) is projected to grow from 39.81 million metric tons in 2001-02 to 52.32 million metric tons in 2006-07 @5.6% per annum. Our crude oil production as per the Tenth Plan Working Group is estimated to hover around 33-34 million metric tons per annum even though there will be increase in gas production from 86 million standard cubic meters per day (2002-03) to 103 million standard cubic meters per day in (2006-07). Only with joint venture abroad there is a hope of oil production to increase to 41 million metric tons by (2016-17). The gas production would decline by this period to 73 million standard cubic meters per day. The increasing gap between demand and domestically produced petroleum is a matter of serious concern.
In other words, our dependence on import of oil will increase in the foreseeable future. The Working Group has estimated import of crude oil to go up from 85 million metric tons per annum to 147 million metric tons per annum by the end of 2006-07 correspondingly increasing the import bill from $ 13.3 billion to $ 15.7 billion. Transport sector remains the most problematic sector as no alternative to petroleum based fuel has been successful so far. Hence petroleum based fuels especially petroleum diesel (HSD) will continue to dominate the transport sector in the foreseeable future but their consumption can be minimized by implementation of Biodiesel program expeditiously. Targets need to be set up for biodiesel production to achieve blending ratios of 5, 10 and 20 percent in phased manner. The estimated biodiesel requirements for blending with petroleum diesel over the period of next 5 years are given in Table 1:

Biodiesel requirement for blending

3 Feasibility of producing biodiesel as diesel substitute: While the country is short of petroleum reserve, it has large arable land as well as good climatic conditions (tropical) with adequate rainfall in large parts of the area to account for large biomass production each year. For the reason of edible oil demand being higher than its domestic production, there is no possibility of diverting this oil for production of biodiesel. Fortunately there is a large junk of degraded forest land and unutilized public land, field boundaries and fallow lands of farmers where non-edible oil-seeds can be grown. There are many tree species which bear seeds rich in oil. Of these some promising tree species have been evaluated and it has been found that there are a number of them such as Jatropha curcas and Pongamia Pinnata (‘Honge’ or ‘Karanja’) which would be very suitable in our conditions. However, Jatropha curcas has been found most suitable for the purpose. It will use lands which are largely unproductive for the time being and are located in poverty stricken areas and in degraded forests. It will also be planted on farmers’ field boundaries and fallow lands. They will also be planted in public lands such as along the railways, roads and irrigation canals.
Proposed Jatropha Plantation: Jatropha curcas has been found the most suitable tree specie for the reasons summarized below:

• It can be grown as a quick yielding plant even in adverse land situations viz. degraded and barren lands under forest and non-forest use, dry and drought prone areas, marginal lands and as agroforestry crop. It can be planted on fallow lands and along farmers field boundaries as hedge because it does not grow too tall as well as on vacant lands alongside railways, highways, irrigation canals and unused lands in townships etc. under Public/Private Sector Undertakings.

• The seeds of Jatropha are available during the non-rainy season, which facilitates better collection and processing. The cost of plantation is largely incurred in the first year and improved planting material can make a huge difference in yield.

• Raising Jatropha plant and its maintenance creates jobs for the rural poor, particularly the landless, in plantation and primary processing through expellers.

• It has multiple uses and after the extraction of oil from the seeds, the oil cake left behind is an excellent organic manure, the bio mass of Jatropha curcas enriches the soil and it can also be put to other uses.

• Retains soil moisture and improve land capability and environment.

• Jatropha adds to the capital stock of the farmers and the community, for sustainable generation of income and employment.

Economics of Jatropha biodiesel: In India, it is estimated that cost of Bio-Diesel produced by trans-esterification of oil obtained from Jatropha Curcas oil-seeds shall be approximately same as that of petro-diesel. On The cost of Bio-diesel varies between Rs. 16.59 –14.98 per litre. Assumptions are that the seed contains 35% oil, oil extraction will be 91-92%, 1.05 Kg of oil will be required to produce 1 Kg of Biodiesel, recovery from sale of glycerol will be at the rate of Rs. 40-60 per Kg. The price of Glycerol is likely to be depressed with processing of such large quantities of oil and consequent production of Glycerol raising the cost of Bio-diesel. However, new applications are likely to be found creating additional demand and stabilizing its price. With volatility in the price of crude, the use of Bio-diesel is economically feasible and a strategic option.
Economics of biodiesel in US: US produces biodiesel from edible oil (mainly soya oil), the 100% biodiesel costs around $ 1.25 to $2.25 per gallon depending upon purchase volume and the delivery costs and competes with low sulfur diesel oil. However, it is costlier to normal diesel and the B20 blend costs 13 to 22 cents more per gallon than normal diesel. It takes about 7.3 pounds of soybean oil which costs about 20 cents/pound, to produce a gallon of biodiesel. Feedstock costs are therefore at least $ 1.5 per gallon of soyadiesel. Under the mustard seed program, oil can be produced today for approximately 10 cents/pound and the total cost of producing mustard biodiesel is around $ 1 per gallon. The mustard oils, a low value product contains as much as 90% mono-saturated fatty acids which makes it perfect for biodiesel, balancing cold flow issues with NOx emission issues. US is planning to add 5-10 billion gallons of biodiesel through mustard seeds having mustard meal a high value pesticide that helps keep the price of mustard oil low. In India, it is estimated that cost of Biodiesel produced by trans-esterification of oil obtained from Jatropha Curcas oil-seeds shall be approximately same as that of petroleum diesel. The bye products of Biodiesel from Jatropha seed are the seed oil cake and glycerol, which have good commercial value. The seed oil cake is very good compost being rich in plant nutrients. It can also yield biogas, which can be used for cooking and the residue will be used as compost. Hence oil cake will fetch good price. Glycerol is produced as a bye product in the trans-esterification of oil. These bye-products shall reduce the cost of Biodiesel to make it at par with petroleum diesel. The cost components of Biodiesel are the price of seed, seed collection and oil extraction, oil trans-esterification, transport of seed and oil. As mentioned earlier, cost recovery will be through sale of oil-cake and of glycerol. Taking these elements into account, the price of Biodiesel has been worked out assuming raw material cost of Rs. 3 per kg and varying prices of by-products. The cost of Biodiesel varies between Rs. 9.37 per liter to Rs. 16.02 per liter, depending upon the price assumed for the oil-cake and glycerol. The use of Biodiesel is thus economically feasible.

4 Production of Biodiesel: Many developed countries have active biodiesel program. Currently biodiesel is produced mainly from field crop oils like rapeseed, sunflower etc., in Europe and soybean in US. Malaysia utilizes palm oil for biodiesel production while in Nicaragua it is jatropha oil. The production of vegetable oils globally and in India are given in Tables 2 and 3.

Table 2 : Global production of the major vegetable oils (2001)

Source: Oilworld Weekly, (2002)

Table 3 : Vegetable oil production in India (2001)

Source: Solvent Extractors’ Association of India

4.1 Derivatives of triglycerides (vegetable oils) as diesel fuels: The alternative diesel fuels must be technically and environmentally acceptable, and economically competitive. From the viewpoint of these requirements, triglycerides (vegetable oils/animal fats) and their derivatives may be considered as viable alternatives for diesel fuels. The problems with substituting triglycerides for diesel fuels are mostly associated with their high viscosity, low volatility and polyunsaturated character. The problems have been mitigated by developing vegetable oil derivatives that approximate the properties and performance and make them compatible with the hydrocarbon-based diesel fuels through:
§ pyrolysis
§ micro emulsification
§ dilution
§ trans-esterification
4.1.1 Pyrolysis: Pyrolysis refers to a chemical change caused by the application of thermal energy in the absence of air or nitrogen. The liquid fractions of the thermally decomposed vegetable oil are likely to approach diesel fuels. The pyrolyzate had lower viscosity, flash point, and pour point than diesel fuel and equivalent calorific values. The cetane number of the pyrolyzate was lower. The pyrolyzed vegetable oils contain acceptable amounts of sulphur, water and sediment and give acceptable copper corrosion values but unacceptable ash, carbon residue and pour point.
4.1.2 Micro-emulsification: The formation of micro emulsions (co-solvency) is one of the potential solutions for solving the problem of vegetable oil viscosity. Micro-emulsions are defined as transparent, thermodynamically stable colloidal dispersions. The droplet diameters in micro-emulsions range from 100 to 1000 Å. A micro-emulsion can be made of vegetable oils with an ester and dispersant (co-solvent), or of vegetable oils, an alcohol and a surfactant and a cetane improver, with or without diesel fuels. Water (from aqueous ethanol) may also be present in order to use lower-proof ethanol, thus increasing water tolerance of the micro-emulsions.
4.1.3 Dilution: Dilution of vegetable oils can be accomplished with such materials as diesel fuels, solvent or ethanol.
4.1.4 Trans-esterification: Trans-esterification also called alcoholysis, is the displacement of alcohol from an ester by another alcohol in a process similar to hydrolysis. This process has been widely used to reduce the viscosity of triglycerides. The trans-esterification reaction is represented by the general equation. RCOOR’ + R" = RCOOR" + R’OH. If methanol is used in the above reaction, it is termed methanolysis. The reaction of triglyceride with methanol is represented by the general equation. Triglycerides are readily trans-esterified in the presence of alkaline catalyst at atmospheric pressure and at a temperature of approximately 60 to 70°C with an excess of methanol. The mixture at the end of reaction is allowed to settle. The lower glycerol layer is drawn off while the upper methyl ester layer is washed to remove entrained glycerol and is then processed further. The excess methanol is recovered by distillation and sent to a rectifying column for purification and recycled. The trans-esterification works well when the starting oil is of high quality. However, quite often low quality oils are used as raw materials for biodiesel preparation. In cases where the free fatty acid content of the oil is above 1%, difficulties arise due to the formation of soap which promote emulsification during the water washing stage and at an FFA content above 2% the process becomes unworkable.
4.2 Process variables in trans-esterification: The most important variables that influence trans-esterification reaction time and conversion are:
§ oil temperature
§ reaction temperature;
§ ratio of alcohol to oil;
§ type of catalyst and concentration;
§ intensity of mixing ;
§ purity of reactants.
4.2.1 Oil Temperature: The temperature to which oil is heated before mixing with catalyst and methanol, affects the reaction. It was observed that increase in oil temperature marginally increases the percentage oil to biodiesel conversion as well as the biodiesel recovery. However, the tests were conducted up-to only 60°C as higher temperatures may result in methanol loss in the batch process.
4.2.2 Reaction temperature: The rate of reaction is strongly influenced by the reaction temperature. Generally, the reaction is conducted close to the boiling point of methanol (60 to 70°C) at atmospheric pressure. The maximum yield of esters occurs at temperatures ranging from 60 to 80°C at a molar ratio (alcohol to oil) of 6:1. Further increase in temperature is reported to have a negative effect on the conversion. Studies have indicated that given enough time, trans-esterification can proceed satisfactorily at ambient temperatures in the case of the alkaline catalyst. It was observed that biodiesel recovery was affected at very low temperatures (just like low ambient temperatures in cold weather) but conversion was almost unaffected.
4.2.3 Ratio of alcohol to oil: Another important variable affecting the yield of ester is the molar ratio of alcohol to vegetable oil. A molar ratio of 6:1 is normally used in industrial processes to obtain methyl ester yields higher than 98% by weight. Higher molar ratio of alcohol to vegetable oil interferes in the separation of glycerol. It was observed that lower molar ratios required more reaction time. With higher molar ratios, conversion increased but recovery decreased due to poor separation of glycerol. It was found that optimum molar ratios depend upon type & quality of oil.
4.2.4 Catalyst type and concentration: Alkali metal alkoxides are the most effective trans-esterification catalyst compared to the acidic catalyst. Sodium alkoxides are among the most efficient catalysts used for this purpose, although potassium hydroxide and sodium hydroxide can also be used. Trans methylations occur many folds faster in the presence of an alkaline catalyst than those catalyzed by the same amount of acidic catalyst. Most commercial trans-esterification is conducted with alkaline catalysts. The alkaline catalyst concentration in the range of 0.5 to 1% by weight, yields 94 to 99% conversion of vegetable oil into esters. Further, increase in catalyst concentration does not increase the conversion and it adds to extra costs because it is necessary to remove it from the reaction medium at the end. It was observed that higher amounts of sodium hydroxide catalyst were required for higher FFA oil. Otherwise higher amount of sodium hydroxide resulted in reduced recovery.
4.2.5 Mixing intensity: The mixing effect is most significant during the slow rate region of the trans-esterification reaction. As the single phase is established, mixing becomes insignificant. The understanding of the mixing effects on the kinetics of the trans-esterification process is a valuable tool in the process scale-up and design. It was observed that after adding methanol & catalyst to the oil, 5-10 minutes stirring helps in higher rate of conversion and recovery.
4.2.6 Purity of reactants: Impurities present in the oil also affect conversion levels. Under the same conditions, 67 to 84% conversion into esters can be obtained, using crude vegetable oils, compared with 94 to 97% when using refined oils. The free fatty acids in the original oils interfere with the catalyst. However, under conditions of high temperature and pressure this problem can be overcome. It was observed that crude oils were equally good compared to refined oils for production of biodiesel. However, the oils should be properly filtered. Oil quality is very important in this regard. The oil settled at the bottom during storage may give lesser biodiesel recovery because of accumulation of impurities like wax etc.
4.3 Raw material and its quality for the production of biodiesel
4.3.1 Vegetable Oil: Any sediment would collect at the bottom of the reaction vessel during glycerol settling and at the liquid interface during washing. This would interfere with the separation of the phases and may tend to promote emulsion formation. The oil must be moisture-free because every molecule of water destroys a molecule of the catalyst thus decreasing its concentration. The free fatty acid content should be less than 1%. It was observed that lesser the FFA in oil better is the biodiesel recovery. Higher FFA oil can also be used but the biodiesel recovery will depend upon type of oil and amount of sodium hydroxide used.
4.3.2 Alcohol: Methanol or ethanol, as near to absolute as possible, can be used. As with the oil, the water affects the extent of conversion enough to prevent the separation of glycerol from the reaction mixture.
4.3.3 Catalyst: Sodium or potassium hydroxide, preferably the latter. The corresponding alkoxides also can be used, but it is prohibitively expensive. Best results are obtained, if the catalyst is ³ 85% potassium hydroxide. Best grades of potassium hydroxide have 14-15% water, which can not be removed. It should be low in carbonate, because the carbonate is not an efficient catalyst and may cause cloudiness in the final ester. Sodium hydroxide pellets have given very good results. Because quantity of catalyst used is quite less, good quality catalyst (in-spite of high cost) can be used.
4.3.4 Animal fats: The most prominent animal fat to be studied for potential biodiesel use is tallow. Tallow contains a high amount of saturated fatty acids, and it has therefore a melting point above ambient temperature.
4.3.5 Waste vegetable oils: Every year many millions of tons of waste cooking oils are collected and used in a variety of ways throughout the world. This is a virtually inexhaustible source of energy, which might also prove an additional line of production for "green" companies. These oils contain some degradation products of vegetable oils and foreign material. However, analyses of used vegetable oils indicate that the differences between used and unused fats are not very great and in most cases simple heating and removal by filtration of solid particles suffices for subsequent trans-esterification. The cetane number of a used frying oil methyl ester was given as 49, thus comparing well with other materials,
4.3.6 Esters of vegetable oil: they make good biomass fuels as diesel substitutes, provided the following factors receive special attention:
The yield of transesterified product should be >90%.
The fuel should be as neutral as possible (pH 6.5-8.0)
The fuel should be centrifuged at a temperature below the expected ambient operating temperature. Winterization has been suggested as the ideal solution.
The neutralizing agent should form fuel low in soluble salts, free from carbonate groups.
Ash content should be 0.01%. The fuel should be free from alcohol.
4.4 Storability of biodiesel: It was observed that when the biodiesels of different oils were stored, their FFA as well as viscosity increased. However, FFA remained below 1% even after one and a half years of storage. Minimum increase was observed in Jatropha curcas oil biodiesel, followed by rice bran, sun flower and linseed oil biodiesel. During storage, the biodiesels also gained some weight. It may be mainly due to reaction with oxygen in the air.
4.5 Plants in operation / under construction: Different technologies are currently available and used in the industrial production of biodiesel, which is sold under different trademarks. For example, there are the Italian process of Novamont, and the French IFP as given in Table 4. A number of units are manufacturing biodiesel worldwide. These units are using sunflower oil, soyabean oil, rapeseed oil, used-frying oil, jatropha oil, etc. as a source of triglycerides as given in Table 5 & Table 6
A total of 85 plants were identified including a few pilot plants, over 30 small capacity plants (500-3000 tons) mostly with farmers’ co-operative as owner and several big plants in the capacity range of 10,000 to 120,000 tons. Of these, 44 plants were in Western Europe with Italy as the leading country with 11 plants, 29 plants in Eastern Europe with Czech being the leading country with 16 plants, 8 plants in North America and 4 plants in the rest of the world. Overall capacity grew from 111,000 tons per year in 1991 to 1,286,000 tons per year in 1997. USA is the fastest growing newcomer and a number of companies are emerging there. Additional capacities are expected in Japan and the palm oil producing countries like, Indonesia and Malaysia. Actual production grew from 10,000 tons in 1991 to 661,000 tons in 1997. France is the leading producer with 227,000 tons (in 1996). Table 5 gives country wise number of plants, production capacity and feedstock oil used.

Table 4: Available biodiesel production technologies

( Source: Tadashi Murayama)

Table 5: Country wise capacity of the biodiesel plants