Paper No: NC-E-17
22nd National Convention of Mechanical Engineers on Energy Technologies-Strategies for Optimal Utilization of Natural Resources September 9 - 10, 2006 The Institution of Engineers (India)
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Biofuel promotion in Northeastern region of India Om Prakash Chaturvedi
Sanjay Mande
TERI School of Advanced Studies (TERI-SAS) Habitat Place,, Lodhi Road New Delhi - 110003, INDIA Email:
[email protected]
The Energy and Resources Institute (TERI) Habitat Place,, Lodhi Road New Delhi - 110003, INDIA Email:
[email protected]
Debajit Palit
The Energy and Resources Institute (TERI) Habitat Place, Lodhi Road New Delhi - 110003, INDIA Email:
[email protected]
Abstract
that in developed countries like US[1]. The picture is very poor for remote rural areas especially in the villages of Northeast states. India's Northeast also known as the land of the eight sister states, comprising the States of Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland, Sikkim, and Tripura is quite underdeveloped region of the country. Although substantial effort has been made by government to electrify these states but the condition is still quite unsatisfactory. The total installed generation capacity of the central, state and private sector in the region is 2309.41 MW [2]. At present more than ten thousand villages are still waiting for electricity, because of complex topography, long distribution line and low load density. Even though some of the villages are connected with grid but due to lack of proper maintenance of transformer and transmission line the real goal of electrification is still not achieved. There are several diesel generators in remote areas used for electrification. But the running cost of diesel generator is too high due to high transportation cost of diesel in these hilly and remote rural areas making them unviable and non-operational in many cases. Despite potential only 25% of the total cultivable land could be brought under irrigation so far depriving others of multiple cropping necessary for food security of the region. Program of promotion of shallow tube well scheme could not become successful and sustainable due to continued rise in diesel price. Diesel is also required to run the tractors, for farm mechanization, for transporting produce to
Northeastern states of India have huge natural resources and biomass is primary energy resource for rural people. Apart from Jatropha, large varieties of oil producing seeds like Nahar, Karanj, Tung, Castor, Votara, Pine etc grow naturally in this region. Steep hike in petroleum prices and its demand in remote far-flung areas of northeastern states make it further attractive option to utilize this energy resource in decentralized manner and has potential to give boost to biofuel/biodiesel programme in the region if demonstrated successfully. This paper emphasizes the need for promotion of bio-oil in the northeast and also suggests technological option for exploitation of this renewable energy source through under peculiar prevailing geographical situation. The study revealed that for energization of remote areas (for mechanical and/or electrical power) preheating of SVO (straight vegetable oil) using hot engine exhaust helps in overcoming its major draw back of higher viscosity and can be an easy option for its use in diesel engine.
1. Introduction Energy is the key pictogram for the development of any country. Now a days various countries are facing energy crises and India is one of them. The average per capita electricity consumption in northeastern states is only 192.3 kWh compared to national average of 592 kWh/capita which in itself is much lower than
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market and for food processing equipments. But rising input fuel cost is hindering overall growth of agriculture sector in the region. During 2003-04, the country imported 90.4 million tonnes (MT) of crude oil valued at US$ 18 billion [3]. The petroleum imports are projected to rise to 166 MT by 2019 and 622 MT by 2047 [4]. Country’s dependence on imported petroleum fuels is constantly increasing due to decline in domestic production of crude oil coupled with rapidly rising demand. Thus, there is an urgent need to explore the alternative substitute for this conventional diesel fuel. Vegetable oils are the most promising candidates as substitute for fossil-derived fuels for diesel engine. The vegetable oils have potential to reduce the country’s dependence on imported fossil fuel and help to make farming communities self-sufficient in the fuel they need to continue their business. The idea is not new. As early as 1900, a diesel-cycle engine was demonstrated running wholly on groundnut oil at the Paris exposition. Interest has been rekindled in bio-oils as diesel fuels and researchers in many parts of the world are applying new technologies to the concept. Generally all the vegetable oil is found to have the similar fuel properties to that of conventional diesel fuel except viscosity, CFPP (cold filter plugging point), carbon residue and ash content. An unmodified engine can perform satisfactorily on neat vegetable oils or their blends with diesel [5]. In this paper an attempt has been made to evolve viable technological option for utilization of nonedible oil in stationery diesel engine that is mostly used in rural as well as agriculture sector without need for its tranesterification.
(Table 1). These areas come under the category of land beside the railways tracks, riverbanks, deforest lands etc. Jatropha plantation on these areas has potential to produce approximately 9.1 MT of jatropha oil. Table 1: State-wise distribution of wastelands under National Mission on Bio-diesel for Jatropha plantation in India (2005)
States
Total available geographical area (km2)
Potential area for Jatropha plantation (km2)
Arunachal Pradesh 83743 9972 Assam 78438 14565 Manipur 22327 12624 Meghalaya 22429 9889 Mizoram 22081 4071 Nagaland 16579 8404 Tripura 10486 1275 256083 60800 TOTAL Source: http://www.indiastat.com (17 July 2006)
3. Technology for utilization of bio-oil There are three common ways to run a diesel engine on biofuel using vegetable oils. All three can be used with both fresh and used oils. Convert it to biodiesel; Mix/blend with petroleum diesel fuel, or with biodiesel; Use the oil just as it is - usually called SVO fuel (Straight Vegetable Oil).
2. Potential of bio-oil in northeast
3.1 Converting to Biodiesel One of the most common methods used to lower the vegetable oil viscosity is called transesterification. The transesterification process creates esters from vegetable oil by using an alcohol in the presence of a catalyst. This reaction takes a triglyceride molecule, or a complex fatty acid, neutralizes the free fatty acids and removes the glycerin, thereby creating an alcohol ester. One method of transesterification mixes alcohol (methanol and ethanol) with catalyst (potassium and sodium hydroxides) and then aggressively mixes the resulting methoxide or ethoxide with vegetable oil. Once the methoxide or ethoxide and vegetable oil are reacted, the resulting mix at biodiesel and glycerin needs to settle using a
Main three species identified in northeastern region for energy plantation are Jatropha curcas L (Bhotera, Ratanjot/Jangli erenda), Pongamia pinnata (Karanj/Karach) and Mesua ferea (Nahar) [6]. Of all the above prospective plant candidates as substituting diesel fuel, Jatropha curcas stands at the top and sufficient information on this plant is already available [7]. One hectare Jatropha plantation with 4,400 plants per hectare under rain-fed conditions can yield about 1,500 liters of oil. It is estimated that about 3 million hectares plantation is required to produce oil for 10% replacement of current petro-diesel consumption. Approximate 23% area in northeast states has been found suitable for jatropha plantation
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may not be very attractive as even presently landed cost of petro-diesel is quite high in remote areas which ideally would be target population for promotion of bio-fuels.
settling tank. A further refinement used is a washing process with water to wash out gum present in esters. The biodiesel production flow chart is presented in Fig. 1.
3.2 Mixing or blending with diesel Vegetable oil is much more viscous (thicker) than petro-diesel. The purpose of mixing it or blending it with other fuels is to lower the viscosity to make it thinner so that it flows more freely through the fuel injection system into the combustion chamber. The blends containing 10 to 30 percent jatropha oil has their kinematic viscosity and relative density compatible for use in diesel engine [8]. The performance test of 3.73 kW (5 HP) engine in terms of brake power, fuel consumption, brake specific fuel consumption, brake thermal efficiency, energy input and emission of CO, UBHC and NOX indicate that these parameters are comparable with diesel on blends having jatropha oil upto 40 percent observed under fuel consumption test. On the basis of 12 hours rating test, performance of engine on blended fuels containing 10 to 30 percent jatropha oil in respect of above parameters was found to be comparable with diesel. But beyond 30 per cent engine performance decreased as percentage of jatropha oil increased in the blend. The mixing option is so far good for the partial replacement of diesel fuel. However, complete replacement cannot be achieved through blending or mixing process.
Vegetable Oil Preheating of vegetable oil Alcohol Catalyst Rigorous shaking the mixture at selected temperature and time Allow the mixture for separation of layers after completion of reaction Glycerol separated Water
Washing of ester
Removal of water containing excess of alcohol and catalyst
Dry the ester by heating at 1000 C for 10 minute
Ester/Biodiesel
Fig. 1: Flow chat for biodiesel production Numbers of studies have been conducted so far on different feedstocks for biodiesel production and its utilization in diesel engines. Most of these studies reported that the performance of diesel engine on biodiesel was satisfactory and comparable with that of diesel engine. High cetane rating of biodiesel is the additional advantage for the biodiesel user. The lower emission makes it popular fuel among the community. From transportation point of view biodiesel is best fuel compare to petrodiesel fuel as it is more reliable requiring minimal additional maintenance. However, for decentralized power generation in remote rural areas it might not be always feasible or even advisable. Centralized large scale-production of biodiesel is more preferable as it requires extensive chemical inputs, technological expertise and skilled labour. Also substantial transportation cost is involved in centralized collection of bio-oils from widespread geographical areas and redistribution of processed biodiesel. Therefore in geographical conditions as prevailing in northeast this route
3.3 Use as SVO (Straight Vegetable Oil) Straight vegetable oil (SVO) fuel systems can be a clean, effective and economical option. SVOs, referred to as neat vegetable oils are derived from oil seeds either edible or non-edible seeds oil. SVOs can be directly used in diesel engines. There are several advantages of SVO over the biodiesel especially for the decentralized manner the SVO can work in rural remote area, where the availability of power is almost uncertain. The comparison of SVO and biodiesel fuel is given in Table 2. The oil extracted from the oil seeds can be used for decentralized power generation or pumping irrigation water as well as for various farm operations using tractors and machinery. Therefore promotion of use of SVO in remote rural areas can be easier approach compared to biodiesel for quickly exploiting potential of biofuels in India. The production technology and use of SVO in diesel is explained in the following paragraph.
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Table 2: Comparison of SVO (Straight Vegetable Oil) and Biodiesel as fuel SVO
Production
Biodiesel
Principle
Decentralized small oil expellers
Chemical compounds needed
No
Energy input
12 %
Central, big industrial units Alcohol (methanol/ethanol), Catalyst (NaOH/KOH) 29 %
Very fast No Regularly no or small
Delayed Small Toxic
Environment
Biological degradation Danger of water pollution Human toxicity
Social acceptability
Strategy Small, decentralized Big, central Logistics Simple Complex Transportation Short distances Long distances Regional income generation High Low Sources: http://www.jatropha.org/p-o-engines/svo-bd-characteristics.htm Sequence of operations employed for the production of SVOs is shown in Fig. 2. Various technologies are used for oil extraction (Table 3).
Mechanical oil extraction is the most common technology in use for extracting nonedible oils. The typical recovery efficiency of good expellers is in the range of 80-85% of oil content in the seed. The main problem faced while using SVO as engine fuel is due to its high viscosity and high flash point. The high viscosity interferes with the fuel-injection process in the engine, leading to poor atomization of fuel and inefficient combustion. Heavy smoke emissions and carbon deposition in the combustion chamber have been reported. Unlike biodiesel, with SVO we have to modify the engine. The best way is to fit a heat exchanger into fuel tank and heated it by using hot engine exhaust gases. There are also two-tank SVO systems, which pre-heat the oil to make it thinner. Here the engine is started on ordinary petro-diesel from first tank and then switched to SVO from the other tank when it gets heated to desired temperature, and engine is switched back to diesel mode before stopping the engine. The integrated preheated system is shown in Fig. 3. It is proven that the kinematic viscosity of jatropha decreases with increase in the oil temperature. Drop in the viscosity of jatropha oil is very fast upto 70°C and there after the viscosity decreases comparatively at slower rate. Beyond 110°C viscosity of jatropha oil becomes comparable to diesel fuel in the range of 2.5 to 7.0 cSt as specified by BIS [9].
Seeds Dehulling Hull Grinding Steam
Steaming Steam Oil extraction Seedcake Filtration SVO
Fig. 2: Production process for SVO Table 3: Oil extraction technologies Extraction technology
Capacity
Screw or hydraulic press
5 -30 kg/batch
Ghanis (animal-driven or motorized) Expellers Solvent extraction
Up to few hundred kg/day 50 -3000 kg/h 200 -4000 tonnes/day
Sources : TERI 2005
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2. 3.
4.
5. 6. Fig. 3: Engine operation with preheated jatropha oil using hot engine exhaust gas The study conducted on preheated jatropha oil revealed that almost all gaseous emissions are reduced as jatropha oil temperature increases. Negligible SOX emissions and decreased in NOX emissions with increased preheating of jatropha oil were reported during the entire experiments. The performance of diesel engine on SVO is compatible with diesel.
7.
8.
4. Conclusions
Northeastern region of India is rich in natural energy resources such as biomass. About 23% of geographical area (mainly degraded forest land and shifting cultivation hilly areas) having potential of jatropha cultivation is capable of producing about 9 MT of oil. These potential areas also happen to be remote habitation where penetration of conventional/fossil energy source is difficult. Use of SVO therefore is preferred option than centralized production of biodiesel for exploiting this potential. Successful experimental study on operating diesel engine on preheated (using hot exhaust gas) SVO showed encouraging performance. Therefore decentralized use of SVO for energization of these remote areas for irrigation pumping as well as electricity generation would be more appropriate option for harnessing this renewable energy source.
9.
References 1.
State wise per capita electricity consumption as per new definition. http://indiastat.com (accessed on 17 July 2006)
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Power sector profile of Northeastern region; Report of the Ministry of Power, (http://powermin.nic.in.), 2003. K A Subramanian, S K Singal, M Saxena, S Singhal. Utilization of liquid Biofuels in automotive diesel engines: An Indian perspective, Biomass and Bioenergy, 29, 65 – 72, 2005. TERI DISHA (Directions, Innovations and Strategies for Harnessing Action) for sustainable development, The Energy and Resources Institute, 2002. E G Shay, Diesel fuel from vegetable oils: status and opportunities. Biomass and Bioenergy, 4, 227-242, 1993. A K Sharma., D Konwer and P K Bordoloi. Non-edible oil seeds of Assam as the potential source for biodiesel production. In Proceedings of the International Conference - Prithvi 2005; Thiruvananthapuram, Kerala: Swadeshi Science Movement, 2005 K Becker, and G Francis. Biodiesel from Jatropha plantations on degraded land. University of Hohenheim, Stuttgart, Germany, 2005. O P Chaturvedi, S P Mande and T K Bhattacharya. Exhaust emission characteristics of a low horsepower compression ignition engine on dieseljatropha curcas oil blends. National symposium on Biodiesel - a sustainable renewable fuel for India. CTAE, MAPUAT, Udaipur, India, 2004. O P Chaturvedi, and S P Mande. Energizing diesel engines with preheated Straight Vegetable Oil (SVO). International conference and expo on Biofuels - 2012: Vision to reality, India Habitat Center, New Delhi, 2005.
