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Power from farm wastes ISRO technology to drive bus A miracle crop?
THIS UNIVERSE |
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Power from farm wastes THE agricultural activities at the farms generate heaps of biomass residues, which are, generally, left in the fields to prevent soil erosion and replenishing nutrients back into the soil. Agricultural wastes can be used to produce three types of energy. Liquid fuels such as ethanol or pyrolysis oil; gaseous fuels like biogas (methane) and electricity. Ethanol fuel which can be used as transport fuel can be produced by lignocellulosic conversion of wastes into ethanol. The combustion of biomass and rapid condensation of its vapors or smoke yields the oil called pyrolysis oil, which is nearly equivalent to diesel. Around 20 per cent of charcoal is also produced as a by-product, which can be used as cooking fuel for rural households. The pyrolysis oil technology was developed in early 1990s in Europe and North America and is now maturing. At present, some plants in Canada, U.S.A. and China are producing oil from various agriculture residues. Recent experiments in Sweden on running a 5 MW diesel power plant on pyrolysis oil have been successful. An innovative experiment in Missouri provides one example of the possibilities. Corn is used to produce ethanol, and the waste from the process is fed to cows for dairy production. Cow manure is utilized in the fields of corn and also run through a digester to produce biogas. A fuel cell efficiently converts the biogas into electricity to run the operation. The end products are ethanol, electricity, and milk. All the waste products are used within the project to lower costs With the initiative of an innovative private firm and the villagers, a power plant has been set up in the village Kirugavalu, about 40 kilometers off the Bangalore-Mysore highway. The plant uses agricultural wastes such as sugarcane refuses and coconut fronds for producing the power. Villagers sell such wastes to the plant and get access to quality power at commercial rates. The waste, which was once burned in open fields, has now become an extra source of income and offered jobs to plenty of villager youths. The power unit set up by Malavalli Power Plant Private Limited (MPPL) supplies electricity to 48 villages in Mandya district. The power plant has a capacity of 4.5 megawatts and is among the largest biomass-based power installations in India. Such more plants can be set up in other parts of country on the concept of Public-Private-Partnership (PPP) to make the farmers self reliant. “This is very essential to keep the plant generating power year-round, without any disruption in the supply of fuel,” says Purushottam Nayak, the plant manager. So, we have established a supply chain to procure agricultural waste from villages in a radius of 10 kilometers and transport it to the plant. Nearly 400 people are engaged in this exercise, while the unit has provided direct employment to 60 villagers. The plant needs about 170 tons of waste every day. The waste is chopped up and conveyed to the boiler for combustion. The heat that is generated makes steam, which then drives the turbine to produce electricity, explained. The power plants could either be small scale (500 kW) running on producer gas from agricultural residues or medium scale (10-20 MW) running on direct combustion of these residues. The technology for this is very mature and there are thousands of such plants running all over the world. A part of these agricultural residues can also be used via the bio-digester route to produce fertilizer for the crops and methane gas to either run rural transport, irrigation pump sets or for cooking purposes. Thus, the residues if properly utilized can produce fuel, fodder and fertilizer besides taking care of India’s burgeoning energy needs. The writer is Assoc. Prof. (Physics), Dept. of Chem. & Physics, CCS HAU, HISAR |
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ISRO technology to drive bus THE massive and widespread environmental pollution caused by the fossil fuel guzzling global transport sector has been counted among the factors for the ongoing process of global warming. The befouling of the urban atmosphere across the world by an exploding number of automobiles has been blamed for growing incidence of asthma, respiratory disorders and other potentially life threatening afflictions. In fact, a study carried out by Mark Jacobson and his colleagues at Stanford University pleads for a speedier introduction of hydrogen fuel cell technology to propel the fossil fuel consuming autos. For such a step could reduce the death caused by various ailments that have their roots in atmospheric pollution linked to automobile emissions. Of course, for many years now launch vehicles equipped with cryogenic engine working on liquid hydrogen as fuel and liquid oxygen as oxidizer have been in use to deliver the satellite payloads into their designated orbits. But then there have been no serious global efforts to exploit this technology for hydrogen fuel cell development. However, ISRO known for its "out of the way and innovative approach" to technological challenges is now close to achieving a breakthrough in developing and qualifying a hydrogen fuel cell for operating a bus. Here ISRO has fallen back on some of the technological elements developed for India's homegrown cryogenic engine stage that will flight tested in a GSLV(Geosynchronous Satellite Launch Vehicle) mission slated for 2009.GSLV flights that were accomplished till now carried a Russian supplied upper cryogenic stage. The Indian cryogenic stage which will replace the Russian supplied upper stage in the three stage GSLV features a regenerative cooled engine capable of generating a thrust of 69.5-kN in vacuum. ISRO Chairman G.Madhavan Nair has made it clear that the hydrogen fuel cell system is not exactly the cryogenic technology. It is ISRO's expertise in handling liquid hydrogen which has given a push to the project aimed at developing a hydrogen fuel cell system for use in transportation sector. V. Gandhi, leading the team of ISRO researchers working on the project says ISRO and Tata Motors had entered into an agreement in 2006 to design and develop a hydrogen fuel cell for operating a Tata bus. Everything going a planned the hydrogen fuel cell system will be integrated into the Tata bus by the first quarter of 2009.Most of the components of the system including gaseous hydrogen and air compressors, coolant pumps, hydrogen storage system as well as regulating system have realized. In this system, hydrogen would fed into the fuel cell, which, in turn, will generate 80 kW electric power to drive the bus. |
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A hardy but pedestrian plant is doing triple duty in California’s agricultural heartland. The seeds are then crushed to extract oil for blending into environmentally friendly biodiesel. If that were the end of the story, it would be just another case of farmers turning food into fuel. Yet at John Diener’s Red Rock Ranch in this town 60 miles southwest of Fresno, the selenium-rich canola byproduct has an even higher calling: cattle feed naturally infused with an essential
micro-nutrient. “It’s all part of what we have to try to do here to turn a profit,” said Diener, who also grows almonds, tomatoes, grapes and corn on 5,000 acres. In a trial, Diener’s canola meal - grown on once-fallow land - was fed to dairy cows on the east side of the San Joaquin Valley, where selenium does not occur naturally and has to be added to food rations. If the USDA’s experiment is successful, officials say they will try to persuade other farmers in the region to start planting canola and other selenium-tolerant plants. “These challenges force farmers to become smarter, and that’s where science comes in,” said Gary Banuelos of the U.S. Department of Agriculture’s research station in Parlier, who manages test plots at Diener’s ranch. There is urgency to the effort because the ongoing drought and court-ordered water rationing to protect threatened fish species means farmers who have relied for decades on state and federal water deliveries via canals are being forced to turn to groundwater pumping. Irrigation water that passes through the soils picks up toxins as it percolates. And what to do with that drainage has vexed farmers, water managers and attorneys since the Bureau of Reclamation’s drainage ponds at the Kesterson Reservoir closed in the 1980s after selenium caused often-fatal birth defects in millions of waterfowl. —AP |
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THIS UNIVERSE There is some scattering in space. This is with radiation, very thin residual gas, perhaps even dark matter. Astronomers can detect some of the consequences of this interaction and scattering. For example, people working in cosmic rays say that the relative abundance of nuclei of cosmic rays carries the effect and scars of this scattering. There are also investigations and some projections of how some of the high energy components of distant signals have been altered by collision with the photons of the Cosmic Microwave Background Radiation. I must warn you that all these are effects that only fine focused measurements can detect. But from layman's point of view there is little scattering and the sky looks essentially dark in which stars and galaxies are just decorations. Why does water vapour not fall down to earth because of
gravitational force? Water vapour is a gas. One molecule of water contains two atoms of hydrogen and one of oxygen. Chemists would say its molecular weight is 2+16 = 18. Molecular weight of nitrogen is 14+14 = 28 and that of oxygen it is 16 +16 = 32. Therefore you see that air that consists mostly of nitrogen and oxygen is significantly heavier than water vapour. This is what makes water vapour rise in the atmosphere. And this is the reason we have clouds and rain. Rain clouds are not all water vapour. They also have tiny drops of condensed water. When the water droplets are very tiny we have fog. That floats around in valleys between hills. So in answer to your question one can say that the water contained in water vapour does fall down because of gravitational force but only after the vapour condenses into liquid form. Then we call it rain. How is it determined as to which is the best place to look for oil? I think the first step would be look for a gravitational anomaly. If there is a large bubble of oil or gas below the ground it should show up in some anomaly in the gravitational field. This could then be explored further by seismic sounding. You give a big bang to the earth and listen to the reflected vibrations. When there is a sufficiently positive indication, you might go to the more expensive and tedious step of drilling some test holes. I am no expert in the area, but I am sure lot of collateral information and hunches are also used in the beginning. |
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Biomass such as firewood, agricultural residue, bagasse, sugarcane refuses, crop stalks, rice husks, coconut shells, animal dung and waste from agro-based industries can be used to produce power. Direct burning of such wastes is inefficient and leads to pollution, but when combusted in a gasifier at low oxygen and high temperature, biomass can be converted into a gaseous fuel known as producer gas. Although this gas has a lower calorific value compared to natural gas or liquefied petroleum gas, but can be burned with high efficiency and without emitting smoke.
Farmers, water managers and agriculture researchers are closely watching an experiment using canola plants to absorb the salt from soil and water.