Improving Biomass Use Efficiency for Semi-Arid Regions
Anupam Tewari* and Ashwani Kumar
Kautilya Institute of Technology Engineering*
Energy Plantation Demonstration Project CentreDepartment of Botany, University of Rajasthan,
Jaipur, 302004, India.
Tel 00 91 141 2654100 Fax 00 91 141 2565905 E-mail: email@example.com
ABSTRACT: Biomass refers to all the matter that can be obtained from photosynthesis. Most vegetable species use solar energy to create sugars from carbon dioxide and water. They store this energy in the form of glucose or starch molecules, oleaginous, cellulose, and lignocellulose .Biomass appears to be an attractive feedstock for three main reasons. First, it is a
renewable resource that could be sustain ably developed in the future. Second, it appears to have formidably positive environmental properties, notably the recycling of carbon in the biological processes, resulting in no net releases of carbon dioxide and a very low sulphur content. Third, it appears to have significant economic potential provided
that fossil fuel prices increase, quite substantially, in the future.
Key words: Biomass, Wastelands, Biofuels. Bioenergy, Renewable sources of energy.
1.1 Plants absorb energy photo synthetically from the sun producing natural (energy) products as a result. Nevertheless, energy auditing of the production and use of biomass should be continued in order to improve and further understand where energy economies can be made.
1.2 Biomass as feedstock includes materials that can be converted into various solid, liquid, and gaseous fuels using biological and thermo chemical conversion processes. Four broad categories of potential biomass
feedstocks can be identified: (1) organic urban or industrial wastes; (2) agricultural crop residues and wastes including manure, straw, bagasse, and forestry waste; (3) existing uncultivated vegetation including stands of trees, shrubs, bracken, heather, and the like; and (4) energy plantations, which involve planted energy crops either on wastelands as has been done during our previous investigations (Kumar, 2004) or on land brought into production for that purpose, land diverted from other agricultural production, or as catch crops planted on productive land.
1.3 Due to the historically poor status of biomass-related R&D, and its neglect on the part of planners and development agencies, it has been very difficult to change biomass energy systems in terms of their production, harvesting, and energy conversion structures to changing socioeconomic and environmental pressures. Fortunately, this is now changing somewhat, so that there is an opportunity to use biomass efficiently for the production of modern energy carriers such as electricity and liquid fuels and to improve the lack of efficiency associated with traditional biomass fuels such as wood and charcoal. Ideally a successful biomass program should be sustainable and economical, taking into account all costs and benefits, especially spillover and indirect effects, including environmental and health aspects. The focus of this article is, on effective utilization of biomass at rural as well as urban level in India which will improve, environmental concerns, save foreign exchange, and improve socio economic status of rural India.
2.1 SOURCES OF BIO-FUEL:
2.1.1 Biomass can be used in solid or liquid forms. The solid forms of biomass include direct burning of biomass which is most common in rural India as well as burning of cow dung for dung cakes which are also burnt directly or mixed with coal to make round balls of dung and coal powder.
2.1.2 Biofuels in their liquid form, can be classified as as follows:
3.1 . Vegetable oils
Unmodified vegetable oils
Modified vegetable oils
3.3. Oxygenated components
3.1.1. VEGETABLE OILS
Pure vegetable oils, especially when refined and deslimed, can be used in prechamber, indirect-injected engines such as the Deutz model and in swirl-chamber diesel engines such as the Ellsbett diesel model. They are also usable when mixed with diesel fuels. Pure vegetable oil, however, cannot be used in direct-injection diesel engines, such as those regularly used in standard tractors, since engine cooking occurs after
several hours of use. All engine types allow additions of vegetable oils mixed with fuels in reduced and small proportions, but residues and cooking negatively affect short-term engine performance. Some vegetable oils also find application as lubricants and as hydraulic oils. In addition, they can be used in saw machines. In general terms, it is possible to substitute mineral oils for vegetable oils provided that appropriate additives
are included. Plant Sources for vegetable oils. Vegetable oil can be obtained from more than 300 different plant species. Oil is contained mainly in fruits and seeds, yet still other origins exist. The highest oil yields can be obtained from tree crops, such as palms, coconuts, and olives, Jatropha Pongamia, Mahua, Salvadora, but there are a number of field crops containing oils. Climatic and soil conditions, oil content, yields and the feasibility of farm operations, however, limit the potential use of vegetable oils to a reduced number of crops. Apart from the previously mentioned
semirefined oils, vegetable oils can also be used in the esterificated form. Diesel engines malfunction if an excess of carbon is present in the combustion process. It becomes necessary to split the glycerides causing
an excess in the carbon composition. This can be achieved by treating oil with alcoholtransesterification
or by cracking procedures. Ideally, transesterification is potentially a less expensive way of transforming the large, branched molecular structure of the bio-oils into smaller, straight-chain molecules of the type required in regular diesel combustion engines. The so called bio ldiesel fuels are oil esters of a biological origin.
Rape oil methyl-ester (RME) and sunflower methyl-ester (SME) are two biodiesels derived from their corresponding oil seeds. Jatropha curcas has great potential for India as it can be grown on vast areas of wastelands in the regions having rainfall above 35 mm per annum.
Ethanol is a volatile liquid fuel that may be used to replace refined petroleum. It can be obtained from different feedstocks. Among them are cereals, sugarcane, sugarbeet, and tubers as well as cellulose materials, namely, wood and vegetable remnants,
although production in these cases is much more difficult . Attention has been focused lately on other plants such as Jerusalem artichokes, which contain inulin (a fructose polymer), and on converting lignocellulosic materials into glucose to obtain ethanol. The ethanol yield from these products depends mainly on the content in fermentable glucides and on per-hectare yields. Ethanol from biomass can readily be used as a blender in gasoline. To elaborate
ethanol, the biomass feedstock is first separtaed into its three main components: cellulose, hemicellulose, and lignin. Cellulose is hydrolyzed into sugars, mainly glucose, which are then easily fermented into ethanol. Hemicellulose can also be converted into sugars, such as xylose, but it is difficult to ferment to produce alcohol. Lignin cannot be fermented, but it can be used to provide energy for fermentation processes. There is no chemical difference between ethanol derived from biomass and fossil origin ethanol.
Another advantage of ethanol is that is can lower the production of aromatic products found in high octane gasolines. Ethanol is currently produced in two separate ways: synthetic ethanol produced from ethylene derived from hydrocarbon, which is perferred
for industrial uses due to the pureness attained (which can reach values of 99.9% in alcohol), and ethanol obtained from the fermentation of plants rich in sugar or starch, a process that is clearly advantageous when using gasoline as a fuel. Calotropis procera and Euphorbia antisyphilitica have great potential as a source of biofuel from the biomass residue obtained after extracting the hydrocarbons with solvent extraction method. Concerning methanol, although it can be produced from a wide range of raw
materials (namely, wood, dry biomass in general, coal, etc.), at present, it is mainly obtained by synthesis from natural gas or gasoline. The technology for the production of methanol consists of ‘‘gasifying the cellulosic raw material to obtain a synthesis gas
followed by the traditional processes used for fossil fuels whereby the gas is purified and its composition is adjusted for the synthesis of methanol” .
The final energy result is more positive when producing methanol because ethanol is a high-cost, low-yield product with problems derived from storage and effects on soil. Also, methanol is less volatile, thereby less dangerous in case of a traffic accident. Unexpected combustion could be extinguished with water, it pollutes less, it has no sulphur content, and it could be tranformed into a high octane gasoline that may be used in countries not ready to employ engines that are fed directly with methanol. That transformation implies a cost, but it would not be excessive. However, the problem with the production of methanol from biomass remains the optimum size of the present manufacturing units, which, having been designed for fossil fuels, are not readily suitable for a very different raw material.
3. POLICIES THAT INFLUENCE BIOMASS USE:
Obviously, the evolution of biofuel technologies depends as much on economic opportunities and public policies as on enhanced technological options. It is evident that much of the advancement in technological capabilities in India is supported by Department of Science and Technology, Government of India under mission mode projects supporting development of liquid fuel sources from biomass.
Basically the biomass programm must have following five components: 1) Energy R & D strategy, rational use of energy, renewable energies, reduction of environmental impacts of fossil fuels, and dissemination of energy technologies. The energy strategy area includes several sections ranging from global analysis of energy R&D policy options to socioeconomic research in order to understand those factors that foster or hinder the innovation processes of energy technologies. Within this strategy area, important studies on the future of biomass energies, including liquid biofuels, are contemplated with special emphasis on technology dissemination.
The rational use of energy area concerns energy efficiency on the demand side of the energy sector. It covers the reduction of energy consumption and stimulating market penetration of innovative, efficient, and clean technologies with a view to reducing
dependency on external supplies of energy products and to improving the impact of the use of energy on the environment. The area relative to renewable energies has as its main objective to enable and stimulate the introduction of renewable energies into the energy system, which offer substantial advantages from an environmental protection standpoint, CO2 emissions,
and long-term security of energy supply. In addition, new initiatives will be taken to enhance the integration of renewable energies into the economy and society. Included in this area are sections on the integration of renewable technologies in social issues and research on energies from biomass and waste.
4. FUTURE STRATEGIES:
It includes multi sectoral and interdisciplinary
activities focusing on three main objectives: first, to strengthen the scientific base needed to implement the EU’s environmental policy and permit it to reconcile the
notions of human health and safety, environmental protection, and the sustainable management of resources with development and economic growth; second, to contribute to world programs of research into global change; third, to contribute to the development of environmental technologies, techniques, products, and services that meet new needs and could contribute to sustainable economic growth. A number of R&D possibilities for systemic factors pertinent to the future evolution of biofuels production and utilization can be provided by developing effective renewable energy programmes.
It may be concluded that biofuels may be able to contribute to the attainment of a variety of environmental objectives such as the aim of reducing both local air pollution and greenhouse gas emissions and the environmental concerns of maintaining agricultural land in production with a possible move to lower intensity production of crops. From an environmental point of veiw, however, blended fuels consist primarily of gasoline or diesel fuel, which
limits the potential benefits in both emission control and efficiency .
(1). Kumar, A and A. Tewari 2004
Improving the Biofuel Utilization Efficiency in the Rural Villages by Modifying the Fire Stove ‘Chulha’ . In: W.P. Van Swaaij, T. Fjallstrom, P. Helm and A. Grassi (eds)
Biomass for Energy Industry and climate protection.2544-2547.
(2) Kumar, A and A. Kotiya, . 2004.
Some Potential Plants for Bio-energy. In: W.P. Van Swaaij, T. Fjallstrom, P. Helm and A. Grassi (eds)
Biomass for Energy Industry and climate protection.180-183