Usage of Alternative Fuels in Boilers for Cost Reduction
There are different solid, liquid
and gaseous fuels are fried in boilers. Coal,
petroleum-based oils and natural gas are fossil fuels that use in boilers
commonly. Another main boiler fuel is biomass. It is a renewable organic
matter. Examples for biomass include
trees, plants, organic municipal, industrial waste and animal waste. The most
important advantage of biomass is it is low cost. Also it is freely available.
But it is cause for deforestation, water resource depletion and atmospheric
temperature increase. The most effective
alternative fuels for boilers are rice husks, rice straw and bagasse.
Rice husks
Rice husk is an after effect of rice growing. They are year round production of rice crops. Rice husks are not only readily available in large quantities but easy to collect. It has a calorific value of around 13-19 MJ/kg Using husks as a fuel is solves the problem of waste husk disposal. Husks based power plant has the potential to be not only applicable but also highly profitable. The fuel is combusted by using well designed equipment. So this is affect for cost reduction. But a scale down rice husk boilers were never appropriately commercialized until recently due to early combustion technology which could address the specific needs of rice husk combustion. Husks combustion is the one of a most successful and profitable renewable energy source nowadays. Rice husk causes low amount of corrosion. It is therefore a moderately straightforward fuel.
Husk
fired boiler features
·
The
equipment requires less space.
·
Automatic
feeding of husk.
·
Overall
efficiency of 80%.
·
The
best quality steam is given by
the
steam separator.
·
Easy
for installation.
Rice husk ash
Another benefit of using husk as a fuel is rice husk ash. It contains silica. Silica is use for many purposes. Aggregates and fillers for concrete and board production, Economical substitute for micro silica fumes, Absorbents for oils and chemicals and discharge agent in the ceramics industries are important uses of silica. Therefore combustion of rice husk is provide extra income.
Rice straw
Rice straw is infrequently used as a source of renewable energy. The main advantage of rice straw is its easy procurement. But its collection is difficult and its availability is limited. In straw combustion at high temperatures, potassium is combined with other alkali earth materials such as calcium. This in turn reacts with silicates, leading to the formation of rigidly sintered structures on the grates and at the furnace wall. Alkaline earth are also important in the formation of slag and deposits. It means that fuels with lower alkali content are minimum problematic when fired in a boiler.
Bagasse
Bagasse contains
in cellulose, hemicellulose, pentosans, lignin, sugars, wax, and minerals and
its energy potential of 9.6MJ/kg and is
utilized for combined heat and power generation within the sugar industrial units.
The variety of sugarcane in adding to harvesting methods and efficiency of the
sugar processing is effect on the composition of bagasse. The fuel value of
bagasse is depend on its calorific value. The calorific value is mainly depend
on its sugar content. 30 tons of wet bagasse is contained in 100 tons of
sugarcane. The bagasse-fired boilers have been used in wide industries for high efficiency in power generation.
Written by
Didulani Prabhamini
Undergraduate, Department of Civil and Environmental Technology,
University of Sri Jayewardenepura
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