The How and Where

RE tech update feature article Discovery of an unexpected boost for solar water-splitting cells NSLS (National Synchrotron Light Source)*. The NIST facility uses X-rays that can be precisely tuned to measure Biogas chemical bonds of specific elements, and is at least 10 times more sensitive than commonly available laboratory the how instruments, allowing researchers to detect elements at extremely low concentrations. While making measurements of the carbon atoms, and where the team noticed spectroscopic data, indicating that the titania nanotubes had small amounts of potassium ions strongly bound to the surface, evidently left by the fabrication process, which used potassium salts. This was the first time potassium has ever been observed on titania nanotubes. Previous ones research team from as a photocatalyst, producing hydrogen were not sensitive enough to detect it. Northeastern University and gas from water, electricity, and sunlight. The result was mildly interesting A the NIST (National Institute of In recent years, researchers have been but became much more so when Standards and Technology), United exploring different ways to optimize the research team compared the States, has discovered, serendipitously, the process and create a commercially performance of the potassium-bearing that a residue of a process used to build viable technology that essentially nanotubes to similar arrays deliberately arrays of titania nanotubes – a residue transforms sunlight into hydrogen, a prepared without potassium. The that was not even noticed before this pollution-free fuel that can be stored former required only about one- – plays an important role in improving and shipped. third the electrical energy to produce the performance of the nanotubes in Increasing the available surface the same amount of hydrogen as an MW (megawatt) to GW (gigawatt). solar cells that produce hydrogen gas area is one way to boost a catalyst’s equivalent array of potassium-free based Standardized models of biogas from water. Their recently published performance. Thus, a team at the nanotubes. ‘The result was so exciting’, on animal plants suitable for individual results indicate that by controlling Northeastern University has been recalls Northeastern physicist Latika waste in India is 12 households and institutions/ the deposition of potassium on the studying techniques to build tightly Menon, ‘that we got sidetracked from million. Till March 2009, under communities are available, meeting surface of the nanotubes, engineers packed arrays of titania nanotubes, the carbon research.’ Since it has such the National Biogas and Manure specific requirements. can achieve significant energy savings which have a very high surface-to- a strong effect at nearly undetectable Management Programme, over 4.1 Along with the development of plants and related infrastructure, a large pool in a promising new alternate energy volume ratio. They also were interested concentrations, Menon says, potassium iogas represents an million biogas plants in the capacity of of skilled manpower has been trained system. in how best to incorporate carbon probably has played an unrecognized alternative source of energy, 1–6 m3 have been installed. Larger units and deployed for plant construction Titania (or titanium dioxide) into the nanotubes because carbon role in many experimental water- derived mainly from organic have also been set up in many villages, and maintenance. The technology is a versatile chemical compound helps titania absorb light in the splitting cells that use titania nanotubes wastes. In India, the use of farms, and cattle houses. The estimated best known as a white pigment. It visible spectrum. Pure titania absorbs because potassium hydroxide involved is anaerobic digestion, which biogas derived from animal biogas production from these plants is has been successfully extended to is found in everything from paint to in the ultraviolet region, and much is commonly used in the cells. 3 Bwaste, primarily cow dung, has been over 4.1 million m per day, which is treat industrial and urban wastes on a toothpastes and sunscreen lotions. of the ultraviolet is filtered by the By controlling it, she says, hydrogen promoted for over three decades now. equivalent to a daily supply of about large scale. This holds potential as a Thirty-five years ago, Akira Fujishima atmosphere. solar cell designers could use it to 3 According to the 1997 Livestock Census, 2.5 million m of natural gas. solution to numerous environmental startled the electrochemical world by This brought them to the NIST optimize performance. the cattle population in the country These plants usually provide problems, including waste and manure demonstrating that it also functioned X-ray spectroscopy beamline at the WWW.SCIENCEDAILY.COM is about 290 million. The estimated thermal, electrical, and mechanical handling, water pollution, and carbon potential of household biogas plants power, generating electricity from dioxide emission. *The NSLS is part of the Department of Energy’s Brookhaven National Laboratory. 1 VOLUME 2 • ISSUE 6 JUNE 2009 VOLUME 2 • ISSUE 6 JUNE 2009 13 feature article feature article for promotion under the National Biogas different categories and areas for setting Programme. up biogas plants (Table 3). Standard capacity Provision of loans For family-type biogas plants, approved The RBI (Reserve Bank of India) and models are available for 1–6 m3 and NABARD (National Bank for Agriculture 1–10 m3 capacities for fixed-dome and and Rural Development) support the floating-drum plants, respectively. The biogas programme. Detailed guidelines commonly used capacities of these are available with both commercial models are 1–4 m3 (Table 2). and cooperative banks for financing family-type biogas plants under the Cost Agricultural Priority area. NABARD The cost of installation varies according provided automatic refinancing facility to the model and size of the plant. The to commercial banks for loan amounts average estimated cost of the most disbursed for biogas plants. popular Deenbandhu model is given in Table 3. The cost of a biogas plant Table 3 National Biogas Programme: central subsidy for different Types of biogas plants categories and areas for setting up biogas plants (2009/10) Table 1 Model household biogas plants/appliances approved for Fixed-dome type Category/area Central subsidy per plant promotion under the National Biogas Programme The fixed-dome biogas plant consists Table 2 The average estimated cost Model - Design guidelines Contact address of the most popular Deenbandhu North-eastern states and Sikkim Rs 11 700 of one lower segment (digester) and model (except plain areas of Assam) a hemisphere over it (gas holder). I. Fixed-dome biogas plant Plant capacity Cost per plant (in rupees) Plain areas of Assam Rs 9000 The mixing tank is connected to the 1) Deenbandhu model with brick masonry MNRE State Implementing Agencies Code practices (second revision) Web site: mnre.nic.in 3 digester by a 15-cm asbestos cement 1 m3 7000 Jammu and Kashmir, Himachal Pradesh, Rs 4500 (restricted to Rs 3500 for 1 m IS 9478:1989 of the BIS, New Delhi Uttaranchal (excluding Terai region), fixed dome type) pipe. Through the outlet hole provided 2 m3 9000 Nilgiris of Tamil Nadu, Sadar Kurseong in the digester, the slurry is pushed into 2) Deenbandhu ferrocement model with MNRE State Implementing Agencies and Kalimpong sub-divisions of 3 m3 10 500 the outlet tank. in situ technique Web site: mnre.nic.in Darjeeling, Sunderbans, and Andaman 4 m3 12 500 and Nicobar Islands 3) Pre-fabricated RCC fixed-dome model MNRE State Implementing Agencies Floating-drum type Web site: mnre.nic.in Scheduled caste, scheduled tribe, Rs 3500 (restricted to Rs 2800 for 1 m3 The floating-drum type biogas plant desert districts, small and marginal fixed dome type) consists of a deep well-shaped increases by about 30% in hilly areas and farmers, landless labourers, Terai II. Floating drum biogas plant region of Uttaranchal, Western Ghats, underground digester connected by by 50%-60% in the north-eastern region 1) KVIC floating metal drum type MNRE State Implementing Agencies of the country. and other notified hilly areas inlet and outlet pipes. A mild-steel gas Code practices (second revision) Web site: mnre.nic.in All others Rs 2700 (restricted to Rs 2100 for 1 m3 IS 9478:1989 of the BIS, New Delhi storage drum, inverted over the slurry, fixed dome type) rises and falls around a guide pipe Training 2) KVIC type plant with ferrocement MNRE State Implementing Agencies Construction of biogas plants is a skilled corresponding to the accumulation Code of practices IS 12986:1990 of Web site: mnre.nic.in job. Hence, the scheme has a provision and withdrawal of gas. BIS, New Delhi Khadi and Village Industries Commission (KVIC), Mumbai of providing training to the masons Bag-type and trainers for construction and Made of rubberized nylon fabric, the III. Pragati model maintainance of biogas plants. A total Code of practices (second revision) United socio-economic Development bag-type biogas plant is a portable IS 9478:1989 of the BIS, New Delhi and Research Programme (UNDARP) number of 11 Development and Training unit, which can be conveniently placed Pune centres have been setup in different R&D at any location. The appropriate model Institute/University to tackle trainings IV. Bag-type biogas plant is selected on the basis of technical Bag type biogas plant – Flexi model Swastik House, Khadki for masons and users. This also provides requirements

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