Agrtotechnology OF CROPS FOR BIOFUELS AND BIOENERGY
Agrtotechnology OF CROPS FOR BIOFUELS AND BIOENERGY
Dr. Ashwani Kumar
Professor of Botany
Hon Director, Life Sciences
Energy Plantation Demonstration Project Center,
Department of Botany, University of Rajasthan,
Jaipur, 302004.
Phone 00 91 141 654100 Fax 00 91 141 565905 Email. msku4@hotmail.com
Summary:
Biomass contributes a significant share of global primary energy consumption and its importance is likely to increase in future world energy scenarios. Current biomass use, although not sustainable in some cases, replaces fossil fuel consumption and results in avoided CO2 emissions, representing about 2.7 to 8.8 % of 1998 anthropogenic CO2 emissions. Improved conversion efficiencies, besides a suitable management of biomass resources , could contribute significantly to reduce it unsustainable use, contribute a larger share of final energy demand and lead to a higher rate of fossil fuel substitution per unit of biomass energy. Also the global biomass energy potential is large, estimated at about 104 EJ/a. Hence, biomass has the potential to avoid significant fossil fuel consumption, of the current fossil energy consumption, potentially between 17 and 36 % of current fossil energy consumption and CO2 emissions potentially between 12 and 44 % of 1998 emissions. Modern biomass energy use can contribute to controlling CO2 emissions to the atmosphere while fostering local and regional development. There is significant scope then to integrate biomass energy with agriculture, forestry and climate change policies for example in the context of international measures directed at greenhouse gas emissions, such as clean development mechanisms.
Utilization of biomass for energy and industry allows a significant quantity of hydrocarbons to be consumed without increasing the CO2 content of the atmosphere and thus makes a positive contribution to the Greenhouse effect and to the problems of “global change” as occurs in both industrialized and developing countries. Further the advantages from utilization of biomass include: liquid fuels produced from biomass contain no sulfur, thus avoiding SO2 emissions and also reducing emission of N0x. The production of compost as a soil conditioner avoids deterioration of soil and reduces pollution of waterways and groundwater. Improved agronomic practices well managed biomass plantations will also provide a basis for environmental improvement by helping to stabilize certain soils, avoiding desertification which is already occurring rapidly in tropical countries. Modern bio-energy technologies and bio-fuels are relatively benign from environmental view point and produce very little pollution if burned correctly and completely. The creation of new employment opportunities within the community and particularly in rural areas will be one of the major social benefits from the exploitation of biomass for energy, industry and environment. The specific research work carried out in the areas of biomass production and utilization in less fertile areas will provide satisfactory answers to the double challenge of energy crisis and forced deforestation in the country in general and semi-arid and arid regions of Rajasthan in particular. The possibility of conversion of biomass into strategic liquid fuels and electricity will make it possible to supply part of the increasing demand for primary energy and thus reduce demand for crude petroleum imports which entail heavy expenditure on foreign exchange. Family Euphorbiaceae ( Euphorbia antisyphilitica, E.tithymaloides, E. caducifolia E. royleana E. neerifolia etc and Ascelpiadaceae ( Calotropis gigantea and C. procera ) which have been worked out in previous years ( Kumar, 2000) and will form the basis for further studies.
Introduction:
Worldwide energy consumption is projected to grow by 59 percent over the next two decades, according to International Energy Outlook 2001 (IEO 2001), released by US Energy Information Administration EIA. One half of the projected growth is expected to occur in the developing nations of Asia ( Including China, India and South Korea) and in Central and South America, where strong economic growth is likely to spur demand for energy over the forecast period. Renewable energy use is expected to increase by 53 percent between 1999 and 2020, but its current 9 percent share of total energy consumption is projected to drop to 8 percent by 2020. Oil currently accounts for a larger share of world energy consumption than any other energy source and is expected to remain in that position throughout the forecast period. World oil use is projected to increase from 75 million barrels per day in 1999 to 120 million barrels per day in 2020.
Biomass resources are potentially the worlds largest renewable energy source- annual terrestrial biomass yield of 220 billion oven dry tonnes. Biomass conversion to fuel and chemicals is once again becoming an important alternative to replace oil and coal. Biodiesel from the rape seed oil methylester (RME) by farmers cooperative has production of 2000 t RME per year. A large facility 15000 t RME per year is located at the oil mill at Bruck/Leitha in Austria. RME is excellent substitute for diesel. Already European countries mainly Italy, Germany and Austria are leading in Biodiesel production nearing 500,000 tons in 1997 out of which 2,50,000 was produced in France.( Statt, 1998) The production capacity of biodiesel in Germany was fully utilized in1997, the sold quantity amounting to roughly 100,000 t (Groenen,1998). The technologies for producing bio-oil are evolving rapidly with improving process performance , larger yield and better quality products. The challenge is to develop a process technology which can cope with the significant variation in the composition of the raw material. Another line of action is Camelina sativa . This plant was a traditional oilseed in Europe. It is considered “low input high yield” plant which could enhance the environmental aspect of biodiesel. However it has higher Iodine number (160).
Now it is not as a result of the oil crisis but due to global warming . Carbon dioxide emissions projected to grow from 5.8 billion tonnes carbon equivalent in 1990 to 7.8 billion tonnes in 2010 and 9.8 billion tonnes by 2020. The Kyoto conference agreement last year is not far reaching but indicates the role clear energy sources will play in future. Biomass is renewable, non pollutant and available world wide as agricultural residues, short rotation forests and crops . Thermochemical conversion low temperature processes are among the suitable technologies to promote a sustainable and environmentally friendly development. Biomass can play a dual role in greenhouse gas mitigation related to the objectives of the United Nations Framework Convention on Climate Change (UNFCC) i.e. as an energy source to substitute for fossil fuels and as a carbon store.
The sustainable development of large areas of the world is today one of the greatest challenge . How will it be possible to provide the means for improving the socio-economic conditions of the increasing population in Developing countries, a large part of which lives in villages and rural areas of Asia, Africa and South America. Biomass currently supplies about a third of the developing countries energy varying from about 90 percent in countries like Uganda, Rwanda and Tanzania to 45 percent in India, 30 percent in China and Brazil and 10-15 percent in Mexico and South Africa. Tropical deforestation is currently a significant environmental and development issue. The annual tropical deforestation rate for the decade 1981-1990 was about 15.4 million ha (Mha). According to some estimates the forest cover is 64.01 Mha accounting for 19.5 percent of India’s Geographic area. At present there is hardly 0.4 percent forest cover below 25 cm rainfall zone and 1.3 percent above 30 percent. Since the annual photosynthetic production of biomass is about eight times the worlds total energy use and this energy can be produced and used in an environmentally suitable manner and mitigating net CO2 emission, there can be little doubt that the potential source of stored energy must be carefully considered for future energy need. The fact that nearly 90 percent of the worlds population will reside in developing countries by about 2050 probably implies that biomass energy will be with us forever unless there are drastic changes in the world energy trading pattern.
Biomass should be used instead of fossil energy carriers in order to reduce i) CO2 emissions ii) the anticipated resource scarcity of fossil fuels and iii) need to import fuels from abroad.
Current commercial and non-commercial biomass use for energy is estimated at between 20 and 60 EJ/a representing about 6 to 17 percent of the world primary energy. Most of the biomass is used in developing countries where it is likely to account for roughly one third of primary energy. As a comparison, the share of primary energy provided by biomass in industrialized countries is small and is estimated at about 3 percent or less.
Global land availability estimates for energy crop production vary widely between 350 and 950 million hectares ( Alexandratos , 1995). An energy potential of about 37.4 EJ/a is estimate based on country specific biomass yield and an average land availability The worldwide technical biomass energy potential is then estimated at about 104 EJ/a corresponding to approximately one third of the global 320 EJ/a primary energy consumption of oil, gas and coal ( BP-Amoco 1999).
Bio-oil consortium of UK received huge grants ( 1.16 million pounds) to enable commercial production and testing of integrated Bio-Oil and electricity generating plant. UK energy minister Peter Hain ascribed “ high priority to research and development of sustainable energy sources “. Commercial processing plants for the medium scale production of biodiesel from inter-esterification of triglycerides have been developed in France, Germany(CARMEN), Austria(ENERGIA Biodiesel Technology) USA (Ensyn Group Inc.) and in EU (Eubia ).
Liquid and gaseous transport fuels derived from a range of biomass sources are technically feasible. They include methanol, ethanol, di-methyl esters, pyrolytic oil, Fischer-Tropasch gasoline and distillate and biodiesel from (i) Jatropha , Pongamia pinnata, Salvadora persica, Madhuca longifolia and ( ii) hydrocarbon from Euphorbia species.
Biomass energy is experiencing a surge in interest in many parts of the world due to : greater recognition of its current role and future potential contribution as modern fuel in the world energy supply, its availability versatility and sustainable nature; a better understanding of its global and local environmental benefits, perceived potential role in climate stabilization, the existing and potential development and entrepreneurial opportunities. technological advances and knowledge which have recently accumulated on many aspects of biomass energy; greater understanding of the possible conflict of food versus fuel etc. A recent World Bank report concluded that “Energy policies will need to be as concerned about the supply and use of biofuels as they are about modern fuels.. (and) they must support ways to use bio-fuels more efficiently and in sustainable manner ( World bank, 1996)
Biomass resources are potentially the worlds largest and sustainable energy source a renewable resource comprising 220 billion oven dry tones (about 4500 EJ) of annual primary production. The annual bio-energy potential is about 2900 EJ though only 270 EJ could be considered available on sustainable basis and at competitive prices.
Most major energy scenarios recognize bio-energy as an important component in the future worlds energy. Projections indicate the biomass energy use to the range of 85 EJ to 215 EJ in 2025 compared to current global energy use of about 400 EJ of which 55 EJ are derived from biomass(Hall and Rosillo-Calle. 1998).. .
Despite for the fact that biomass represents about one third of the energy consumption in developing countries, it is not taken very well into account in energy studies. A set of factors explain the slow growth on the biomass utilization . They include:
1. High costs of production
2. Limited potential for production
3. Lack of sufficient data on energy transformations coefficients.
4. Low energy efficiency and
5. Health hazard in producing and using biomass.
In the large scale use of biomass for energy risks are insecurity in raw material supply and prices, doubts about adequate quality assurance and hesitance for a wider acceptance by the Diesel engine manufacturers, mission marketing strategies for targeting Biodiesel differential advantages into specific market niches and last not least missing legal frame conditions similar to clean air act in the USA.
Review of the work done in our laboratory:
Background:
A 50 ha Energy Plantation Demonstration Project centre in the semi- arid region of Rajasthan was used to conduct the investigations. Arid and semi arid lands occupy one third of the earth’s surface. Indian arid zone occupies an area of about 0.3 million sq. km. 90 percent of which about 2,70,000 sq. km.) is confined to north west India covering most of Western Rajasthan, part of Gujrat and small portions of Punjab and Haryana. These area also experience high temperatures and moderate to strong winds during summer. The potential evapo-transpiration over these parts varies from 160 to 200 cm, thereby causing great deficit of water. Due to adverse climatic conditions and edaphic factors vegetation is very sparse with thorny trees.
First efforts to cultivate hydrocarbon producing plants for fuel production were made by Italians in Ethiopia and French in Morocco. later on Calvin and his collaborators have revived the idea again and have advocated the study of petro-crops as a possible feedstock for petroleum like materials. India with its vast expanse of wasteland unsuitable for agricultural production (nearly 180 million ha ) and could be considered for economically viable production of bio-fuels.
A large number of hydrocarbon yielding plants are able to grow under semi arid and arid conditions and they also produce valuable hydrocarbons ( upto 30 percent of dry matter) which could be converted in to petroleum like substances and use as fossil fuel substitute. During the last 18 years investigations have been carried out on the optimization of yield and production of hydrocarbons by such plants at the 50 ha Energy plantation demonstration project center (EPDPC) University of Rajasthan, Jaipur. Their yield could be increased several fold making their commercial cultivation feasible.
Hydrocarbons from plants;
Some of the laticiferous plants identified by Bhatia et al ( 1983) were investigated in detail at Jaipur ( see review Kumar et al 1995 and Kumar 2000 and Kumar 2000 and 2001) .
Work already done:
Indian Scene and hydrocarbon production by plants:
India has a land mass of approximately 329 million ha. Approximately 175 million of land is degraded land with productivity below its potential . The most practical way to develop Biomass energy systems is to make use of land resources that are presently under used or completely unsuitable for conventional agriculture. Most of the plants of desert area produce economically important highly reduced organic compounds such allow molecular weight hydrocarbons. Although they have overall growth rate lower than that of conventional crops, these plants allow improved water economy by producing a greater energy content per unit of dry weight biomass. Thus the most important logical approach for bio-energy production is to develop proper agro-technology for the plants that produce oils and hydrocarbons having high energy value.
Work already done in our group:
The work on the development of suitable agro-technology for hydrocarbon yielding plants was initiated in in 1980 with seeds of Euphorbia lathyris provided by Professor Melvin Calvin (Kumar, 1984).
Certain potential plants were selected and attempts were made to develop proper agro-technology for their large scale cultivation. Initially work was initiated at 5 ha and subsequently extended to 50 h Energy Plantation Demonstration Project Center.
Methodology employed :
Certain potential plants were selected and attempts were made to develop agro-technology for their large scale cultivation (Kumar, 1984, 1994, Kumar et al, 1995, Kumar 1996, Kumar,1998; Roy, 1998- see review Kumar 1995, Kumar 2000). A 50 ha bio-energy plantation demonstration project center has been established in the campus of the University of Rajasthan to conduct the experiments on large scale cultivation of selected plants with the objective of developing optimal conditions for their growth and productivity, besides conserving the biodiversity.
The work done included:
i.) hydrocarbon yielding plants ii,) high molecular weight hydrocarbon yielding plants, iii) non edible oil yielding plants
(i) Hydrocarbon yielding plants included :
1. Euphorbia lathyris Linn.
2. Euphorbia tirucalli. Linn.
3. Euphorbia antisyphilitica Zucc.
4. Euphorbia caducifolia Haines.
5. Euphorbia neriifolia Linn
6. Pedilanthus tithymalides Linn.
7. Calotropis procera (Ait.)R.Br.
8. Calotropis gigantea(Linn)R.Br.
II) High molecular weight hydrocarbon yielding plants :
1. Parthenium argentatum Linn.
III)Non edible oil yielding plants
Jatropha curcas.
Simmondsia chinenesis
.
IV) Short rotation energy plants
Acacia tortilis
Holoptelia integrifolia
Parkinsonia aculeata
Cassia siamea
Albizzia lebbek
Acacia nilotica
Tecomella undulata.
Prosopis juliflora
Pithocellobium dulce
Azadirachta indica
Dalbergia sisso
V) Hill plants growing on Aravallis:
Anogiessus pendula
Boswellia serrata
Considerable work has ben carried out on these plants (Kumar, 1987,1994, 1995,Kumar 1996. Kumar and Roy, 1996 Roy and Kumar, 1998, 1990). Investigations on several plant species have been carried out at our center including Euphorbia lathyris (Garg and Kumar, 1987a ; 1987b, 1989a, 1989b, 1990; Kumar and Garg, 1995) Euphorbia tirucalli (Kumar and Kumar, 1985, 1986;; Kumar and Kumar 1986) Euphorbia antisyphilitica (Johari et al, 1990,1991; Johari and Kumar, 1992,1993a 19995) Pedilanthus tithymaloides (Rani et al. 1991;Rani and Kumar, 1994a); Calotropis procera (Rani et al, 1990) ; Euphorbia neeriiifolia and E. caducifolia (Kumar 1990, 19994) Jatropha curcas (Roy 1990, 19991, 1992b, 1994. 1996; Roy and Kumar Kumar, 1990 ) and Simmondsia chinensis(Roy 1992a).
(1) Propagation;
In general these plants are easily propagated through cuttings. the optimum period for raising cuttings is June -July and March -April. Cuttings from apical and middle portions of E.antisyphilitica exhibited 100 percent survival rate while none of the cuttings from the basal portions survived. Besides cuttings treated with growth regulator IAA showed longest root length in a certain time period. Spacing among the planted cuttings is also a crucial factor for survival of cuttings. It was noted that initially upto period of two months the survival percentage was maximum in closest planting density . However for better results in later stages they must be transferred to beds having a minimum distance of approximately 45.0 cm. At this optimum density productivity of E. antisyphilitica was the best. (Johari, 1992). Regarding environmental variations, March to October period was best suitable for E.antisyphilitica because of linear increase in growth was recorded in the period (Kumar, 1990). During these months, maximum sprouting was observed in Pedilanthus tithymaloides, E.antisyphiliitca and E.tirucalli. Cuttings measuring around 15 cm in length and 1 cm in diameter gave optimal growth. Seeds of Jatropha curcas and E.lathyris also showed maximum germination during these months. Overall growth and productivity was lowest in the winter months from November to February. Higher accumulation of hexane extractable corresponded with higher temperatures of summer season (Johari and Kumar, 1992).
Edaphic factors:
Among different soil types sand was best for the growth of E. lathyris (Garg and Kumar,1990) and P. tithymaloides (Rani et al, 1991) while red loam soil was best for E. antisyphilitica. However for E.lathyris latex contents were maximum on sand gravel. Red soil was rich in nitrate, sodium, potassium and phosphorus pentaoxide(Johari and Kumar 1992). E. antisyphilitica plants were relatively tall in sandy soil and less branched as compared to red soil. plants grown in red soil branched more instead of increasing much in height. When different combinations of these soil types were made biomass of E.antisyphilitica was maximum in red+sand+gravel (Johari,Roy and Kumar, 1990). While red +sand combination in equal amounts was best for P.tithymaloides (Rani, Roy and Kumar, 1990). A mixture of gravel +sand favored maximum increase in plant height fresh weight and dry weight in E. lathyris (Garg and Kumar, 1990: Kumar and Garg, 1995).Environmental factors influenced the growth and yield of Calotropis procera (Rani,Roy and Kumar,1990)
Growth curve:
Growth of these plants was promoted by relatively higher temperatures. Maximum growth was observed during June-July to October-November and also from February march to may June. increase in hexane extractable was recorded upto 6-7 months; thereafter per cent hexane extractable (HE) did not increase significantly in E.lathyris. E.antisyphilitica and P.tithymaoildes. Higher levels of HE were recorded in leaves as compared to the stem in E. lathyris and in fruits of Calotropis procera.. Active phase of growth exhibited greater amounts of hexane extractable.
Fertilizer application:
Application of NPK singly or in various combinations improved growth of all the selected plants. in general NP combination gave better growth which was only slightly improved by the addition of K for E.tirucalli.(Kumar and Kumar, 1986). When of best doses of NPK were applied in different combinations like NP, NK, KP and NPK the last combination gave best results in the form of biomass, latex yield sugars and chlorophyll in E.lathyris (Garg and Kumar, 1990) and P.tithymaloides (Rani and Kumar, 1994a). In E. antisyphilitica however NP combination gave best results, followed by NPK for biomass production. Chlorophyll sugars and latex yield was best in , combination (Johari and Kumar, 1993a).
Addition of FYM alone and with combination of urea improved the growth and productivity of E.antisyphilitica, E.lathyris (Kumar and Garg, 1995), FYM+ Urea application improved the productivity in comparison with FYM application alone. In E.lathyris addition of FYM increased the plant height fresh weight and dry weight to varying degrees. hexane and methanol extractable also increased (Garg and Kumar, 1896,1987a)
Micronutrients, B, Zn, Cu, Mn, Fe, and Mo were applied to E.antisyphilitica, E. lathyris and P. tithymaoildes in different concentrations. their soil application resulted in general promotion in fresh and dry biomass, latex and chlorophyll yield. Foliar spray was given to E.lathyris . In this plant best results were given by Mg application followed by Cu, B,Fe,Mo,Zn and Mn(Garg and Kumar,1987a).
Salinity stress studies were Laos made of on Euphorbia tirucalli (Kumar and Kumar, 1986). Salinity was applied in the form of irrigation water. Lower concentrations of salinity improved plant growth of E. antisyphilitica (Johari, Roy and Kumar, 1990). but higher concentrations inhibited further increase in growth. Sugars however did not increase in any saline irrigation. A slightly higher level of salinity impaired chlorophyll synthesis also. At higher level of salinity leaves of E.antisyphilitica became yellow and fell down but stem did not chow any visible adverse effects. E. lathyris also could also tolerate lower salinity levels but its tolerance was higher than E.antisyphilitica. In E.lathyris salinity adversely affected the root growth (Garg and Kumar, 1990).
P.tithymaloides also exhibited increases in biomass and yield at lower salinity levels and higher concentrations adversely affected the plant. Its underground part could tolerate slightly higher salinity concentration (Rani, Roy and Kumar, 1991). Saline irrigation was also given with different percentage of FYM added in the soil. Both E.antisyphilitica and P.tithymaloides exhibited tolerance of higher salinity levels with increasing percentage of FYM in the soil, biomass sugars, biocrude and chlorophyll all increased in proportion with increasing FYM levels in the soil and along with saline irrigation. It was found in EL that upto a certain level FYM causes increase in overall growth and yield along with different concentrations of saline irrigation. Beyond a certain level increased FYM did not improve growth and productivity. P. tithymaloides required still higher percentage of FYM in the soil for best yield and biomass.
Lower salinity levels increased the sugar contents in sand. Higher saline concentrations adversely affected the chlorophyll contents but with increase in manure supply the chlorophyll accumulation was promoted in P.tithymaloides. Effect of water stress was studied. Five different percentages of field capacity of soil were determined and plants were irrigated. Aboveground plant biomass improved significantly with increasing percentages of FC maximum being 100 percent FC irrigation., in E. antisyphilitica was well as in P. tithymaoildes. plant height also increased linearly with increasing soil water status, however under ground length was found to increase upto certain level only. Irrigation beyond an optimum level tended to reduce biocrude, sugar and chlorophyll in E. antisyphilitica. In P. tithymaloides lowest FC gave maximum yield of hexane extractable and chlorophyll. Sugar however increased with increasing levels of field capacity irrigation. percent dry matter yield also decreased with increasing the quantity of irrigation water to the soil in E.antisyphilitica and P. titymaloides (Rani and Kumar, 1994a)
Application of growth regulators:
Exogenous application of growth regulators has been reported for several horticultural and ornamental plants and sugarcane. in EA. in present experiment maximum plant height was observed in GA3, followed by CCC, NAA, 2,4,5-T and IAA. Spray of growth regulators resulted in enhanced fresh and dry weight production (Johari,Roy and Kumar, 1991). However bio-crude synthesis occurred more in auxins, NAA and IAA in E. antisyphilitica. Out of all the growth regulators employed on P. tithymaoildes IAA supported maximum plant growth in terms of fresh weight and dry weight dry weight of aboveground and underground plant parts. 2,4,5-T showed minimum plant growth , besides certain nodular structures were observed on the stem of the plants treated with 2,4,5,-T . biocrude yield was best in IAA followed by 2,4,5-5T, GA3, CCC, NAA and control. Application of growth regulators on P. tithymaloides resulted in slight decrease in chlorophyll over the control plants. whereas on E.lathyris they induced favorable results, regarding chlorophyll (Garg and Kumar, 1987a).
In E.lathyris IBA caused maximum fresh weight productivity followed by IAA, GA3 and NAA. NAA sprayed plants exhibited more production of hexane extractable. Favorable influence of growth regulators was also observed in sugar yield maximum being in NAA followed by IBA GA3 and IAA(Garg and Kumar 1987b).
The cultivation of these plants suffers from plant pathogenic diseases affecting at root level. Investigations on pathogenicity and control aspects of Charcoal rot of E.lathyris. (Garg and Kumar, 1987c); E.antisyphilitica (Johari and Kumar, 1993b ) were carried out.
Tissue culture techniques:
Plant tissue culture has been successfully employed to achieve rapid clonal propagation of E.lathyris (Kumar and Joshi,1982); Pedilanthus tithymaloides(Rani and Kumar,1994 b) and E.antisyphilitica (Johari and Kumar, 1994). Likewise propagation of jojoba has also been carried out (Roy 1972a).
Jatropha curcas Linn is potential diesel fuel oil yielding plant and details about this are given in Roy and Kumar, 1988 and Roy, 1999.
Survey of laticiferous plants :
Calotropis procera is widespread in semi and arid regions of Rajasthan, while Calotropis gigantea is confiend to south eastern parts of Rajasthan, Udaipur division and adjoining areas. Most of the hills of Jaipur Ajmer Udaipur and Chittor region are covered with E.caducifolia and E. neerifolia. J. curcas is found in abundance in Ranakpur to Udaipur and hills of Udaipur division.(Roy, 1999) . E. antisyphilitica was introduced from the National Botanical Research Institute, Lucknow and is able to grow in the absence of irrigation for long periods.
Liquefaction
Liquefaction is relatively low temperature high pressure catalytic process, often carried out in reducing atmosphere (hydrogen or CO) or using a hydrogen donor system. Since liquefaction is carried out in the liquid phase, heat transfer is improved, whilst the reducing atmosphere results in a product with a low 02 content improving the quality of calorific value.
Conclusion:
Cultivation of energy crops with low input of external means of production- in as far as this is possible- results in fundamentally poorer energy yields but better emission balances compared with the more intensive methods. However detailed investigations at the 50 Ha EPDP center have resulted in formulation of strategies for their large scale cultivation of biofuel plants.
Biodiesel characterization:
Diesel engine exhaust (DEE) is classified carcinogenic to experimental animals and as probably carcinogenic agent to humans by International Agency for Research on Cancer (International Agency for Research on Cancer, 1989). The mutagenic and cytotoxic effects of particulate extracts of diesel engine exhaust (DEE) using rape seed oil methylester(RME) and soyben oil methylester (SME)as fuels were directly compared to DEE from fossil diesel fuel(DF) (Bunger et al,1998.)The results indicate a higher mutagenic potency of DEE of DF compared to RME and SME.
Comments