Sugar cane - an energy crop


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Sugar cane - an energy crop

  1. 1. Sugarcane - an Energy cropDr.K.Rajendran Ph.D
  2. 2. Energy Content of Sugar-cane Sugarcane is an Energy rich Crop and one Ton ofCane contains about 4500 MJ energy in which about1800 MJ is lost in the boiler flue gas and about 750 MJheat energy is dissipated to atmosphere through thecooling tower / spray pond.Energy of one ton of cane approximately equivalentto 1 barrel of oil One ton of bagasse at 50% moisture produces about2.15 tons of steam, and 5.8 tons of bagasse (50%moisture) equals 1 ton of oil.
  3. 3. Energy products of Sugar canePower/electricityAlcoholEthanol
  4. 4. Individuals, Society, Organization, States, Nationsand entire world aim for Sustainabledevelopment.Sustainable development benefits entirecommunity in all aspects viz. social, economic,technological, and environmental.
  5. 5. Present situation in IndiaIndian Sugar Industry in India characterized by High cost of production and 80% of the costproduction goes towards raw material aloneOld ,out dated and obsolete Technologies,Small factories i.e. less than 2500 TCD Relatively concentrating on Sugar onlyHence the need of the hour….Sugar production alone is not profitable.Electricity generation, production of Alcohol andEthanol are important to ensure sustainabilityand financial viability and survival in thecompetitive environment.
  6. 6. Why diversification is needed in sugarindustry?Integrated production of sugar, ethanol andenergy as electricity offers viable potential.Demand for Fuel ethanol is rapidly growing inIndia.Import substitution for Petrol/Crude andconservation of Foreign exchange
  7. 7. Cogeneration, the combined generation of steam andelectricity, is an efficient and cost-effective means to saveenergy and reduce pollution. Many studies around the worldhave identified sugar mill cogeneration as an attractive low-cost option to place additional generating capacity on thegrid.Several studies revealed that the sugar industry as a primecandidate for supplying low-cost, nonconventional powervia cogeneration and the advantages of sugar millcogeneration include relatively low capital costrequirements and the use of a renewable, indigenous wasteas a “non-polluting” fuel.( Smouse et al.)
  8. 8. What is cogen?Cogeneration means simultaneous production of heat and power,with a view to the practical application of both products. Heat is mainproduct, electricity by-product or alternate, uses heat that is lostotherwise.Cogeneration is not new to the cane sugar Industry , but howeverCogeneration based on High pressure boilers and extractioncondensing or straight condensing machines are definitely new to theindustry All sugar plants are Cogenerating power right from their inception,Cogeneration for surplus power generation has gained momentum in1993.Cogeneration scheme should consider the available bagasse,variations in the bagasse availability during season and availability ofcoal or biomass during off season and process steam requirements inthe factory during crushing season..
  9. 9. Benefits of cogenCost of production of power per unit is very cheap.Quick return on investments.Restore ecological imbalance. Reduced use of fossil fuel.Ability to use Bio-Mass and other locally available organic mattersAvailability of power during crushing period- between Nov. to May.economic and timely solution of Power problems in the country.Reduction CO2 in the environmentConservation of Natural ResourcesLower T&D losses
  10. 10. Cogen principleWhen steam or gas expands through a turbine, nearly 60 to 70% ofthe input energy escapes with the exhaust steam or gas. This energy in the exhaust steam or gas is utilized for meeting theprocess heat requirements. Such an application, where the electrical power and process heatrequirements are met from the fuel, is termed as “Cogeneration”.Cogeneration is the most efficient way of generating electricity andheat from a given amount of fuel. It saves between 15-40% of energywhen compared with the separate production of electricity and heat.A number of different fuels(multiple fuel) and proven, reliabletechnologies can be used It is also known as ‘Combined Heat and Power (CHP)’ and ‘TotalEnergy System’. Power and Combined Heat and Power (CHP) playsan important role in sustainable development.
  12. 12. Pre requisitesFeed water quality control and Boiler Water Management, An effective bunker system for the storage of bagasse, moisture in thebagasse controlled to a value of around 50%., turbine for the Sugar plant Cogeneration-servicing and sparesavailability,Process side steam Economy,design of the electrical systems for the Cogeneration parallel thecogeneration plant at 110 kV level. Distributed Control System(DCS) skilled Man Power,
  13. 13. Some considerationsThe initial investment of cogeneration projects may behigh but payback period is low( between 3-5 years). The payback period and profitability of cogenerationschemes depends upon realisation of sales price forelectricity. Environmental concerns, new avenues for nonconventional energy sources and increased demand forpower are likely to improve market conditions forcogeneration.
  14. 14. Where energy savings in sugar millsConversion from low Pressure to HP Boilers(Saving of Bagasse byadopting high technology HP Boilers, Reduction of moisture inbagasse 50 to 45% by improving Milling Technique).Mill House/Crushing section-Reducing moisture percentage inBagasse, Reduction in consumptions of power per Ton of Cane byinstalling Variable frequency drives and high efficient auxiliaries.Evaporator section(Reduction in Process steam consumptions inevaporator and Prime movers by installing Planetary Gear systemsReduction in live steam consumption
  15. 15. Save power inside the factory toexport more power to gridElectrical Energy consumption can be reduced by incorporatingvarious Energy Efficient Equipment like , VFD, Energy EfficientTransmission gears, pumps and motors, etc. and thereby power exportcan be increased.Energy efficient gears may be introduced Feeder table, Cane Carrier,Milk of lime stirrers, Crystallizers drives, Molasses and magma pumps,Pug-mills and Magma Mixers, etc to save power consumption in thefactory.Condensers & Cooling System, Energy efficient Pumps and Motors,Juice and Water Flow Meters
  16. 16. 1 ton of cane gives 125 units of Power of which 35 units required forthe mills and 90 units of may be exported to Grid.In addition1) Sugar (9.5% recovery) : 95 kg2) Molasses ( 4.5%) : 45 kg(10.8 Lit of Ethanol)3)Press mud ( 3%) : 30 kg(Recovery is considered at 9.50 %)(As per the amended Sugar cane control order, if Ethanol is produced directly from Juice 60liter will be obtained)
  17. 17. One ton of Molasses gives Rectified Spirit : 220 Litres or Ethanol : 210Litresor ENA ( Extra Natural Alcohol) : 215 Litres
  18. 18. Molasses is one of the important by product ofthe sugar industry. Molasses, on distillationproduces rectified spirit, extra neutral alcohol,denatured spirit, and ethanol.Alcohol is used in Liquor, pharmaceuticals andchemicals industries.Ethanol is also a valuable fuel, which is blendwith Petrol.
  19. 19. Demand for Alcohol /EthanolDemand for alcohol is increasing every day for IMFL/Chemical industriesMandatory for blending with Petrol and frequentincrease of petro products have increased thedemand for ethanolIn addition to sugar mills, corn based alcohol/ethanolplants are coming up to meet the increased demand.Potential is unlimited for alcohol and ethanol inIndia.
  20. 20. Biofertilisers from canePress mud a byproduct, is sold as such by some millsto the cane growersSome mills process the press mud and sell it asenriched pressmud, which can be directly applied inthe field.Some mills process pressmud with cowdung andearthworm and sell as Vermicompost or fertilisers atahigher price from Rs 1500 per MT
  21. 21. Road aheadSugar complexes instead of Sugar millProduction of sugar, biofertiliser, power, alcohol andethanol under one roof.Increased financial profitability and self relianceTaking care of environment along with the economicdevelopment of farmers and march towardssustainable development.