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The total power generation capacity in India is about 105000 MW (Thermal, Hydel, Nuclear and other non-conventional energy sources), of which more than 2/3rd is coal based and this will continue in the near future. Power station coals contain high ash percentage (35 – 45%) which results in large quantities of ash generation, (bottom ash – 20% and fly ash 80%) during the combustion process. The earlier practice of ash disposal was through sluicing of bottom ash and fly ash with water and pumping into the ash pond.
What is Fly Ash?
Fly Ash is a fused residue of clay minerals present in the coal. High temperature during burning of coal in thermal power plants, transforms the clay minerals present in the coal powder into a variety of fused fine particles of mainly aluminium silicate composition. Thus, Fly Ash is a unique by-product of thermal power plants, possessing both ceramic as well as pozzolanic properties.
Pulverised coal burnt in the boilers form around 80% Fly Ash and 20% Bottom Ash. The Ash is carried away by flue gas collected at economizer, air pre-heater and ESP hoppers. Clinker type ash collected in the water impounded hopper below the boilers is called Bottom Ash.
Fly Ash as a resource material
Fly Ash has been found to be an excellent resource material, based on its inherent characteristics. The quality of Fly Ash depends on the coal quality, its fineness and operational conditions of the boiler. By virtue of qualifying the Fly Ash in terms of its engineering properties, it can be effectively used for many products.
Uses of Fly Ash
High Volume Applications
Land Reclamation – Mine Fills – Structural Fills – Embankments – Raising of Ash Dykes – In the manufacture of Pozzolana and Ferro Cements – Laying or Roads – In agriculture and horticulture to neutralize soil acidity, plant nutrient and metal extraction.
Value-added Products
Bricks – Blocks – Interlocking Pavers – Curb Stones – Mosaic Tiles – Aggregates – Blended Cement – Aerated Concrete Products.
More innovative uses
Dry Fly Ash can be used effectively to derive high value material like Magnetite, Alumina, Silica, Cenospheres, etc.
These high value material find application in the development of Polymer composite products, Ceramic Composite products, Metal Matrix Composite products of high value. In recent years, Central Power Research Institute (CPRI), Bangalore is carrying out R & D in these areas. |
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Fly Ash-based Bricks, Blocks, Pavers and Curb Stones Manufacturing Unit:
The manufacturing facility has been made semi automatic by providing belt conveyors for feeding processed raw materials, off-bearers to handle the green products and product transfer cars for shifting the green products to the curing area.
Product manufacturing machines are provided with inter-changeable moulds, so that, any desired products can be produced on a semi commercial scale, depending on the demand.
About 50% of Fly Ash can be effectively utilized for the manufacture of Fly Ash Bricks, Blocks, Pavers and curb stones. These products can be either water cured for a period of 28 days or steam cured for a period of 12 hours at atmospheric pressure.
Fly Ash based Mosaic Tiles Manufacturing Unit:
Manufacturing Capacity: 1500 Mosaic Tiles/day.
The manufacture of Fly Ash Mosaic Tiles consists of preparation of mix for the wearing layer and the base layer.
The wearing layer consists of a plastic mix of Mosaic Chips, Cement, Fly Ash and Dolomite powder. The base layer consists of a semi-dry mix of Fly Ash, Cement and Quarry Dust.
The tiles are pressed in the Tile making Machine and air dried for a period of 12 hours (minimum) before transferring to the curing tanks, where they are cured for a period of 15 days under water. The cured tiles are then polished and stacked for supply.
The technical specifications for plant and machinery pertaining to Fly Ash-based Mosaic Tiles manufacturing unit have been drawn by CPRI. The plant and machinery include Pan Rollers, Drum Mixer, Screw Mixer, Mosaic Tiles Manufacturing Machine, Tile Stands, Product Transfer Car, Curing Tanks, Polishing Machine and Tile Cutting Machine.
CASHUTEC – Achievements
- Fly Ash technologies developed at CPRI have been successfully demonstrated on a semi-commercial scale at CASHUTEC.
- The techno-economics of various Fly Ash based products, viz. Bricks, Blocks, Interlocking Pavers, Curb stones and Mosaic Tiles are highly attractive for commercialization.
- Entrepreneurs are keen to implement these technologies in their product manufacturing units.
- Power plants have appreciated the establishment of this centre and are keen on establishing similar facilities, in their Fly Ash utilization programmes.
- Fly Ash products such as Bricks, Blocks, Pavers, Mosaic Tiles and Curb stines manufactured at the Centre have superior properties as compared to conventional products.
- Multi-component Fly Ash product manufacturing facilities have been established at CASHUTEC at low investment costs.
The Future
- With CASHUTEC as the benchmark, such Fly Ash projects can be implemented in other power plants in the country with technical expertise from CPRI.
- Technical support in terms of Quality Assurance, new products, training etc. can be extended from time to time.
- Concept extension of the CASHUTEC Project towards branding, positioning and bringing out the unique selling property of Fly Ash products manufactured at the centre can be done.
Quality Assurance
The Fly Ash products manufactured at CASHUTEC are assessed from time to time in terms of process/product reliability and consistency in quality. Towards this, exclusive test facilities have been set up at the CASHUTEC laboratory for routine evaluation of products and processes. These facilities are also useful to various entrepreneurs in Raichur and adjoining districts.
Development of Entrepreneurs
In addition to training programmes and workshops, awareness building and Fly Ash product promotion by builders, architects and contractors will be organized for the development of entrepreneurs. Awareness campaigns for the promotion of utilization of Fly Ash products and towards increasing environment-friendly options for the utilization of Fly Ash will also be conducted |
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For further details, please contact:
CASHUTEC Society
Raichur Thermal Power Station, Shaktinagar, Raichur 584 170, Karnataka State, India.
Tel: +91 08532 246116 Fax: +91 08532 246118
E-mail: cs@karnatakapower.com Website: www.karnatakapower.com
Department of Forest, Environment & Ecology (E&E)
Government of Karnataka
VII Floor, Multi storeyed Building, Dr. Ambedkar Veedhi, Bangalore 560 001. Indo-Norwegian Environment Programme
#49, 2nd Floor, Parisara Bhavan, Church Street, Bangalore 560 001
Contact: Mr. Chakravarthi Mohan, K.A.S. - Programme Co-ordinator INEP and Ex-officio Director, NGC
Mobile: +91 94482 82199 Tel: +91 80 2532 6185 Telefax: +91 80 2532 6186
E-mail: ineptwo@vsnl.net Website: www.inep-karnataka.org |
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