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| SCIENCE TRIBUNE | Thursday, June 27, 2002, Chandigarh, India |
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Chicken droppings as a fuel for boilers |
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Towards personal flying
machines
The fascination of humans for flying is rightly depicted in the words of an everlasting film song "pankh hote to udd aatti re...". No doubt aeroplanes have fulfilled these dreams to some extent but the formalities and the expenses associated with air flights still have eluded common masses from desired utilisation of air flying. When the individual road transportation modes (i.e. two to four wheelers) have developed fulfilling the individual needs to a great extent the air flight vehicles have not really developed to that level. Some air flight modes such as hot balloon flights and hang-gliders can fulfil the air flying desires of individuals to some extent but the idea to have an efficient, safe, affordable and environmental friendly individual air flight vehicle will always be there in the minds of masses.
The technology that evolved into the Firebird (nickname given to the machine) can be traced back to the mid-1950s in the USA with the development of a one-man portable helicopter. However, it was not until the late 1970s/early 1980s that the rotary-wing aircraft that eventually become Firebird began to take shape. By the mid-80s, a project to construct a one-man helicopter to be known as the "Minicopter" was implemented, under the direction of inventor Gilbert Magill, and by 1986 the first prototype was demonstrated in Europe. In late 1997 a London based British company Intora-Firebird Holdings purchased the rights and patents to the project. The revolutionary new concept in helicopter design was launched at Farnborough International 1998 and attracted great interest. The development of an unmanned version and its appearance alongside the one-man version at the Dubai Air Show at the end of 1999 has generated further interest. The jets use 85%/87% hydrogen peroxide (H2O2) fuel which is fed into the engine in front of a catalyst (silver screens). Hydrogen peroxide is so unstable that a slight coax from a sliver catalyst breaks it down catastrophically into oxygen and steam. Therefore, concentrated solutions of hydrogen peroxide — more than 30 per cent, mixed with water — have acquired a risky reputation because they can start runaway reactions if exposed to impurities in the wrong kind of container. But other rocket fuels such as liquid oxygen are far more hazardous, which may explain why the inventor selected H2O2 as a fuel. Provided that standard safety precautions are followed, 87% Hydrogen Peroxide is no more dangerous than any other aviation fuel. Higher concentrations of H2O2 must be diluted with distilled water. Fuel is stored in stainless steel tanks and should be handled according to manufacturer’s instructions. If the fuel is stored according to the manufacturer’s recommendations it has a storage life of 20 years. From safety point of view, user must ensure that water is available for dilution purposes in the event of spillage. Silver screens are the components of the catalyst unit so they are available only as an integral part of the catalyst unit. When H2O2 comes in contact with silver, a chemical reaction takes place, which results in the H2O2 decomposing into oxygen and water. The heat produced during the chemical reaction causes the water to be converted into super-heated steam. The combined expansion of the oxygen and the super-heated steam causes the hot gas to be released from the engine at supersonic speed, giving a thrust of around 34-38 Ibs per engine. There is no flame or air pollution, the only by-product being oxygen and water, and as the drive is coming from the tips of the rotor blades and not from a centrally located conventional engine, there is almost no torque. However, a tail rotor can be fitted if manoeuvring during hovering is a required option. The helicopter is significantly quieter than a conventional helicopter. The Firebird requires routine inspection and maintenance. The helicopter is designed to be flown after a few hours’ training depending on the pilot’s aptitude. Training can be arranged using the amateur’s own helicopter or a helicopter provided by the training school. The Firebird is controlled by a single handle called the Monotrol. This is moved in the direction the pilot wishes to fly-up, down, right, left, forward, backward or centralised to hover. When the Monotrol is turned right or left, like a bicycle’s handlebar, the helicopter turns in the same manner. Unlike conventional helicopters, the Firebird has no feet-operated controls. The monotrol reduces pilot training because it simplifies all aspects of flight control. Proper air traffic and licensing rules and regulations at local/national/international level related to flying of such helicopters are yet to be framed. In a demonstration, the helicopter took off from a trailer behind a pickup truck, flew under a low bridge, then landed back on the trailer with a precision that no conventional helicopter could match. The manufacturing company claims that Firebird can be ultracheap to build and maintain because it contains so few moving parts. Once the pilot primes the motors, they can suck fuel from the tank continuously. The main rotor drives itself. And because all the thrust occurs at the tips of the blades, Firebird is incredibly manoeuvrable and easy to fly. The copter can be controlled by novices after just a few hours of training. Firebird could whisk commuters to work or lift firefighters into danger zones; an unmanned, radio-controlled variant could conduct agile military surveillance while keeping the pilot safely on the ground. The craft’s small size and extreme mobility would make it hard to shoot down, while its low price would make it expendable. Then farmers could use it to search for cattle, gas companies could use it to inspect pipelines, and anyone could fly it as a high-tech, extra-manoeuvrable ultra light aircraft. Compared to conventional helicopters, the Firebird helicopter is simple to assemble. One person can easily transport the helicopter using a small truck or a trailer. Presently the helicopter has flown in excess of 120 hours without incident. The helicopter’s footrest and monotrol are fully adjustable for people of different heights. Because the Firebird is a modular system so it can easily be adapted for water landings and takeoffs by fitting floats or other suitable equipment. Present development efforts are concentrating on the production of the single seater helicopter but later plans will involve the development of a two-seater helicopter. Currently the assembled helicopter is costing about $ 85,000 (approx. Rs 42 lakhs) however, when mass production begins the price will decrease substantially. For the rest of us, the big question
remains whether Firebird could become the personal flying machine. One
reason for optimism is that some of the key patents are about to run
out. When that happens, the design will be up for grabs, and then
someone might develop a version for private use.
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Chicken droppings as a fuel for boilers A 12.6 MW power station, the first in the world, to use chicken droppings as fuel has now been operating successfully at Eye in Suffolk, eastern England, for the last 10 years. This new breed of electricity plants, developed to use a truly renewable energy source, offers advantages both in terms of electricity generation and in terms of environmental protection, for developing and developed countries of the world. Chicken dropping is a mixture of wood shavings, or straw, and droppings cleared from poultry farms, where birds raised for the table or for laying eggs. The droppings are collected in bulk and transported in covered lorries to the power stations where they are stored in closed warehouses to reduce both odour and dust emissions. The handling cranes feed the droppings into the specially designed furnaces, which heat the boiler to produce the steam driving a turbine, which in turn drives an electricity generator. Power stations fuelled by chicken droppings could be particularly attractive to rural communities in developing countries like India as they could provide local power production on a small scale, while providing a profitable outlet for potentially polluting waste products. Such facilities are best sited close to chicken farming areas and a network of small power stations offers the potential for local, stable power sources. These would stimulate local power production and reduce the problems associated with distant, centralised and frequently unreliable power supplies. In terms of cost, such powerhouses would provide electricity that is comparable with that from coal or gas fired power stations. Another advantage of chicken droppings as a fuel is that it is far cleaner than coal-fired generation. The chemical composition of dropping, which is low in sulphur, chlorine and heavy metals, means that the levels of noxious gases released, such as sulphur dioxide and various oxides of nitrogen, are very low 11 per cent and 2 per cent, respectively, of the levels released by comparable coal-fired stations. The plant is virtually smoke-free, and careful design can minimise the levels of noise near the power station. This constructive use of chicken droppings will also help to solve the problem of their disposal, which may cause concern in areas of intensive poultry farming. Chicken droppings are traditionally used locally as fertiliser, but intensive farming may lead to cover-supply, and a subsequent tendency to apply too much. This may lead to certain areas becoming saturated with phosphates and potash. Moreover, in spite of such heavy use, in some instances there is a surplus, which must be sent for landfill. Its nitrogen content may cause contamination of ground water, not only following fertiliser application, but because seasonal application means that droppings are stored for several months, usually on open sites. This also allows generation of significant quantities of methane, a greenhouse gas 25 to 30 times more damaging to the atmosphere than carbon dioxide, to be released into the atmosphere. In cases when the droppings are used as a fertiliser, there is also a risk of salmonella entering the food chain. The smell from storage sites and from open farm vehicles used traditionally for transportation may also cause considerable local nuisance. Burning, however, does not only generate electricity and solve the environmental problems associated with storage and use as manure; the resultant concentrate ash is still available as fertiliser and is in fact improved in the process. It retains the important phosphate and potash content, but is nitrogen-free and sterile. Moreover, it is lighter and easier to
handle, and could therefore be transported over a far wider area. |
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SCIENCE & TECHNOLOGY CROSSWORD
Across :
Down:
Solution to last week’s Crossword:
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Flying
birds have always fascinated and motivated human kind to develop air
vehicles as a fast mode of transportation. We have always seen angels
flying with wings in books and movies but is this type of flying
technically possible?
A
lightweight, simple to operate, configurable for multiple roles,
easily manoeuvrable and difficult to detect by radar, infrared or
noise helicopter (as shown in figure) has been developed and is under
advance level flying testing in England. With additional specification
like no-gasoline, no-pollution, no-engine, this chopper may become a
personal flier for the rest of us. This unique helicopter uses
Hydrogen Peroxide (H2O2) as a fuel. It can take off and land almost
anywhere. With both manned and unmanned versions available, carrying
various mission payloads, this air vehicle really is "the
ultimate mission platform".
Clues