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Special Issue - 2018International Journal of Engineering Research & Technology (IJERT)ISSN: 2278-0181ICONNECT - 2k18 Conference ProceedingsImprove the Efficiency of Boiler by Reduce theMoisture in BagassePeriyasamy KKarthickannan VAssistant Professor, Department of MechanicalEngineering, Kongunadu College of Engineering &Technology, Tiruchirappalli-621215,IndiaBE (Mechanical Engineering), Department of MechanicalEngineering, Kongunadu College of Engineering &Technology, Tiruchirappalli-621215, India.R KarthikeyanGokulnath ABE (Mechanical Engineering), Department of MechanicalEngineering, Kongunadu College of Engineering &Technology, Tiruchirappalli-621215, India.BE (Mechanical Engineering), Department of MechanicalEngineering, Kongunadu College of Engineering &Technology, Tiruchirappalli-621215, India.Gopinath R NBE (Mechanical Engineering),Department of Mechanical Engineering,Kongunadu College of Engineering & Technology,Tiruchirappalli-621215, India.Abstract: The aim of project is remove the biogases moistureand improve the boiler efficiency. Bagasse is a by-product ofsugar milling and improvement fuel resource for thatindustry. It is a fibrous, low density material with very a verywide range of particle sizes and high moisture content. Itschemical properties are similar to those of hardwood fiber. Itis difficult to characterize the physical properties of bagasseparticles in the usual ways (i.e. by particle density, size, dragco-efficient, etc.).These properties are necessary to applynormal design procedures. For example, pneumaticconveying, fluidization, drying, combustion, etc. Normallygravimetric method is used for moisture contentdetermination. Generally the moisture level up to 50% afterthe milling process. Because of moisture content its calorificvalue are affected. So burning of bagasse at suitable level ofmoisture is essential from the viewpoint of furnaceperformance. Here the moisture is removed by direct andindirect methods. The method of influencing conduction,convection and radiation process. By the utilization of exhaustflue gas as a source for moisture removal of bagasse.gray MR corcoran WH, Gavalas GR. [3] Pyrolysis ofwood derived material, effects of moisture and ash content,industrial engineering chemistry, process designanddevelopment 1985: 24: 646-51. Banerjee, R. and pandey,A. [4] Bio-industrial application of sugarcane bagasse. Atechnology perspective, 2002, Int. sugar Journa. jones PJ.[5] 1981. Down flow of gas-solids mixtures in bottomrestrained vertical standpipes, Ph.D. Thesis, Dept.of chem.Eng., university of Queensland, Australia. hugot,E. [6]Hand Book of Cane sugar engineering 3ᵈ Edition. Elsierscience publishers’ B.V., 1000 Aamsterdam, Netherlands.1986 PP: 872-884. minhas, M.J[7] boiler efficiencycalculations for the new 35 tons boiler at hussain sugarmill, jaranwala, and society of sugar technologists.1985PP:362-375. crawfoed ER. [8]Proc. Qld. Soc. SugarCane Technol. Australia 1954:21:P.132. Lois, J, [9] Sugarcane and co-products. Proceedings of XXXII ATAMConvention, 2009, August.Keywords: Boiler, Bagasse, Calorific Value, Moisture content,Dryer, Heat transfer, Fuel.II. BAGASSE PREPARATION AND STABILIZATIONI.INTRODUCTIONBagasse is a by-product of cane which can beobtains after the extraction of sugar juice from the cane.Moisture is directly influence with its calorific value. Byremove/reduce moisture the performance of furnce isimproved in boiler. Here the moisture is removed by theconduction, convection and radiation process. Generallydrying is refers to the removal of moisture from a solid byevaporation. Based on the mode of heat transfer, Bagassedryers can be classified into two types1. Indirect or non contact dryers.2. Direct or contactdryers.Indian standards IS 6997- 1973[1]. Test code forsugarcane crusers. pressure and temperature are taken asreference from steam tables[2] (S.I.UNITS R.S.KHURMI).Volume 6, Issue 07INDIRECT DRYERS:They are also called as non-adiabatic units, wherethe heat transfer medium is separated from the product tobe dried by a metal wall. In the case of drying of bagasse,the heat transfer is only through conduction and forcedconvection. Irradiative heat transfer taken place because oflower temperature levels of operation. The indirect dryingmethod can be tried for bagasse with low pressure steam(3atm or less) by adopting large tube bundles, inside a largebin. Typically the bagasse moisture can be reduced from50% to 45%. A dryer handling 90TPH through put of wetbagasse at 50% initial moisture can be dried to around86TPH of bagasse at 45% outlet moisture with around 4.0TPH of evaporated moisture. The dryer would consumearound 6.3 tons of low pressure steam. Even afterdiscounting for the energy of steam used and the electricalpower required for the drive of dryer motor, this can bePublished by, www.ijert.org1
Special Issue - 2018International Journal of Engineering Research & Technology (IJERT)ISSN: 2278-0181ICONNECT - 2k18 Conference Proceedingssignificant energy economy because of increased boilerefficiency and increased boiler steam output. The increasein boiler efficiency and the increase in steam to bagasseratio because of lower moisture content in bagasse.A typical indirect dryer for bagasse applicationcan be a bin dryer. The large bin is kept vertical with largediameter (100 or150mm) pipes passing along the verticalaxis at a pitch of 450 to 600mm and bin circumference isalso lined with vertical steam pipes. The pipes are fed atthe top with low pressure steam with radial outlets from acommon feed header, reaching to individual pipes. Thepipes are again connected together at the bottom end andthe condensate removed out of the system. The bagasse ischarged to the dryer at the top from belt conveyors. Thebagasse descends vertically down to the bottom where it isextracted by bagasse extractor. During its travel down thecontainer bin, the bagasse gets dried by physical contactwith the steam pipes and the liberated water vapour travelsup and out of the container bin. As on date there are nonon-contact type bagasse drier functioning any wheresuccessfully. The above description is of a drier withpromising feature that can be given a trial.bagasse that would be carried along. This concept thereforerequires additional investments.There were some contact type direct dryer triedfor bagasse dryer in a certain location in India. The dryerwas later dismantled since there were operational problemthat had to be addressed to, before making it suitable forcontinuous operation. Bagasse drying is a concept whichdeserves additional attention and developmental efforts.Since the ultimate aim is to achieve energy economy in thecombustion of bagasse, it is necessary that the energybalance is always kept in mind while various concepts aredeveloped.Here we select the direct method because theindirect drier method having more conflicts in its operation.In India most of the industries are removed the indirectdrier method for more time consuming and low moistureremoval rate.Its moisture removal rate up to 5% but thedirect drier methods moisture removal rate 8-10% from thenatural moisture of bagasse.III. EXPERIMENTAL SET UPDIRECT DRYERS:Direct dryers or adiabatic or contact type dryer, transferheat contact of the product with the hot gases. The gastransfer sensible heat to provide the heat to provide the heatof vaporization of the moisture present in the solid. It ispossible to obtain some non luminous radiation heattransfer benefit also in this case, since the moisture contentin bagasse is quite high. Direct heating is preferredwherever feasible, for the following reasons.1 .Rate of heat transfer is high due to direct contactbetween the flue gas and the raw material.2. Short residence time.3. Uniform drying.Drum type rotary can be selected for direct drying bagasse.The waste flue gases at boiler outlet or other suitabletemperature level waste gas can be used for this purpose.Generally rotary dryers operate in concurrent mode toavoid possibility of ignition. However, since bagassecontains very high moisture and the waste gases containsignificantly low quantities (less than 10% by weight) ofoxygen, a counter current dryer can be advantageouslyadopted to save on cost and space for dryer installation.Never the less, contact type dryers will have suitableprovision for firefighting because of possibilities ofleakages air ingress.The main component of this dryer is asteel set up on rollers by means of bandages (hoops)located in the shell. The cylindrical is usually inclined witha slope to the horizontal so that the solids slowly progressthrough the dryer under gravity, but the characteristicaction of the dryer is provided by the longitudinal liftingbaffles known as flight, which collect the material andsubsequently shower it through the flue gas stream as thebarrel rotates. These lifters are fastened to the inner surfaceof the drum.The additional requirement for direct (contacttype) dryers, is that it becomes necessary to separate thewaste gases (with dried out moisture) from the fine dustVolume 6, Issue 07Published by, www.ijert.org2
Special Issue - 2018International Journal of Engineering Research & Technology (IJERT)ISSN: 2278-0181ICONNECT - 2k18 Conference ProceedingsCAPACITY OF DIRECT DRIER:i) To dry the wet bagasse from the initial 50% to 40% ofmoistureii) Capacity up to 100 tons per hour or 2250 tons per day,based on input. This drier can use chimney temperature ofas low as 1500 ciii) The same drier can also dry wet bagasse from 50%moisture to 25-30% of moisture, provided the flue gastemperature in the chimney is up to 2000 c.REASON FOR DRYING BAGASSE:A) INCREMENTAL CALORIFIC VALUE:When any fuel is burnt its heat generating capacity isindicated by a term calorific value which means thequantity of heat generated by burning a unit weight of thefuel. The total heat generated by burning a unit of weightof fuel is known as gross calorific value (GCV). If thelatent heat of water vapour in the combustion of gases isnot recovered, it is lost in the flue gases along with thesensible heat of water formed by combustion. The balancequantity of heat is known as Net calorific value (NCV).Water has no calorific value, but on the other hand itabsorbs heat in getting vaporized, and as such this processreduces the calorific value of wet bagasse.All theconstituents of mill wet bagasse with the exception ofmoisture are combustion. But the presence of water inbagasse reduces its fuel value, as a part of the heat value ofbagasse is used for the evaporation of moisture content ofbagasse, before bagasse can catch fire. Thus heat is wasted.High calorific value,HCV (19605-19605(moisture % sample)-19605( ash %sample) -3114(brix % sample) (19605-(19605*50)-(19605*5)-(3114*2)) 8760.0 kj/kg (or) 2091.88 kcal/kg.COMBUSTION:Combustion is an exothermic oxidizing reaction .Itsmechanism is not fully understood, but for practicalpurposes the products of combustion of a fuel such asbagasse can be determined from its ultimate analysis asshown in table 3.1. In a furnace the oxidizing agent is airand the main products of combustion are nitrogen, carbondioxide, water vapour and oxygen. Secondary products arethe Oxides of trace elements such as sulphur, phosphorousand vanadium.The simplest way of measuring combustionefficiency is to determine the percentage by volume ofcarbon dioxide, oxygen and carbon monoxide in the fluegases. A trace of carbon monoxide indicates incompletecombustion whilst the carbon dioxide or oxygen figuresindicate incomplete the quantity of excess air present.The heat released when oxidizing carbon to carbonto carbon dioxide is 14,590 B.T.U/1b while only 10,210B.T.Uj1b are available if carbon is oxidized to only carbonmonoxide. In practice unfortunately, to ensure completecombustion a small amount of excess air is needed.E) ENERGY BALANCE ON DRYING OF BAGASSE:1) Generation of equivalent units of electricity from 200kgs of saved bagasse.2) Net saving of bagasse.3) Monetary value of electricity generated from savedbagasse.Depending on the type of fuel and furnace design, thisvaries from 10Wo 50%, over and above that required fortheoretical combustion. The products of combustion arethus diluted and the efficiency of heat recovery is reduced.The reduction in efficiency, however, due to incompletecombustion far outweighs the loss due to the small amountof excess air required to complete combustion. Fig. 3.1shows the relationship between “excess air” and percentagecarbon dioxide for a number of different fuels.B) HEAT RECOVERY:Bagasse driers offer a great advantage of permitting theflue gas temperatureto be brought down to the lowest level. Bagasse dryinggainfully uses the flue gasses.C) REDUCED AIR POLUTION:Bagasse drying is considered as a method to solve airpollution problems in the co-generation plant.D) BAGASSE SAVING:A 2500 TCD sugar mill generates 750 tons of bagasseper day with 50% moisture. When the same is dried to30% moisture, the increased calorific value even aftertaking into account the weight loss is 20-22%. This impliesthat by drying bagasse up to 30% moisture, sugar factoriescan save 150 tons of bagasse per day with 50% moisture,which will be a saving of 24000 tons on 160 days ofworking the saved bagasse, can be sold to the nearby papermills after depithing & subsequent drying.Volume 6, Issue 07Published by, www.ijert.org3
Special Issue - 2018International Journal of Engineering Research & Technology (IJERT)ISSN: 2278-0181ICONNECT - 2k18 Conference ProceedingsSTEAM CONDITION IN A CANE SUGAR FACTORY:PROPERTIES OF SUGARCANE BAGASSE:CHEMICAL PROPERTIESDESCRIPTIONProximate analysis “as fired”Carbon C%11.5Volatile%37Water%50Ash%1.5Total100Ultimate analysis “as fired”Carbon C%22.5Hydrogen ternator of:Backpressure, passOut/condensing orCondensingdesignPowergenerationCOMBUSTION EQUIPMENT:Combustion equipment must be robust, easy to maintain,consume a minimum of power, and enable the fuel to beburnt as completely as possible in the furnace withoutusing too much excess air. Different fuels require differenttypes of combustion equipment to meet these conditions.BAGASSE:These two fuels, because of their high moisture andvolatile contents are essentially gaseous in character. Themost efficient way of firing them therefore is to introducethem into the furnace in a similar manner to a gas, i.e. witha proportion of the combustion air illustrate typicalfurnaces. Due to their relative bulkiness and the fact thatneither bagasse nor hogged timer can be storedsuccessfully in a diverging bunker, a furnace having largestorage and thermal inertia characteristics can be installed.Fig. 9.2B illustrates a typical example of this type of unit.Should the bagasse supply fail, continuous steaming can bemaintained for a period of some 10 to 20 minutes thusproviding a reasonable time for bagasse to be reclaimedfrom store to maintain load, or in the event of a bagassecarrier failure to enable auxiliary power equipment to bebrought on line.Whilst most of the ash produced in this type ofunit is disposed of while the boiler is on range throughcollectors in the boiler itself, the furnace must be shutdown at weekly factory shutdown. The furnace isextremely simple, has no moving parts and possesses selffeeding characteristics which simplify auto- control. Thestate of the bed is quiescent in relation to suspension firingwhich reduces grit carryover and smut emissionconsiderably. Grit collectors can be dispensed withwhereas they are considered essential with suspensionfiring.IV. BOILER AND TURBINE USED IN KOTHARISUGAR MILLBOILER:In the boiler drum and tubes, water circulates due todifference between the density of water in the lowerVolume 6, Issue 07temperature sections of the boiler. Wet steam from thedrum is further heated up in the superheated for beingsupplied to the prime mover. (i.e., water converted in tosteam)TYPE OF BOILER:BI-DRUM WATER TUBE i.g. 600850 Fa)Electricalb)Steamturbine300-450p.s.i.g. 650750 Fc)Reciprocating steamengine100-250p.s.i.g. sat550 FEvaporators,juiceheaters,pans,etc.,Up to 40p.s.i.a.satSPECIFICATIONHeat transfer areaPressureTemperatureSteam generationWater line:Economizer inlet tempEconomizer outlet tempRemarksPower is generated byexpanding H.P.Steam down to processconditions,i.e.,30-40 psi sat. Wherecondensing facilities areincluded,thus cater forbalancing electrical andsteam loads and/ormeeting off crop powerdemandsPower obtained frommain turbo-alternatorstationSmall horse powersproduce higher steamconditions. Due to highefficiencies,pressurereducing anddesuperheating plantrequired to balancefactory loadHigh capital cost of plantand foundations and oilentrainment in steamhave tended to make thistype of prime moverobsoleteSince the heat transfercoefficient of saturatedsteam is about 10 timeshigher than superheatedsteam, superheatedconditions should beavoided.2503 m² each66 kg/cm²485 C40 TPH each105 CAir line:Air pre-heater inlet temp32 CAir pre-heater outlet tempFlue gas line:Economizer inlet temp 385 CEconomizer outlet temp 210 CAir pre-heater inlet tempAir pre-heater outlet temp250 C180 C210 C140 CTURBINE:Turbines are the hydraulic machines which converts steamenergy in to mechanical energy.The mechanical energy isPublished by, www.ijert.org4
Special Issue - 2018International Journal of Engineering Research & Technology (IJERT)ISSN: 2278-0181ICONNECT - 2k18 Conference Proceedingsused in running an electric generator which is directlycoupled to the shaft of the turbine. Thus the mechanicalenergy converted in to mechanical energy.moisture rate in %TYPES OF TURBINE:BLEED CUM BACK PRESSURE TURBINE.SPECIFICATION:Number of stages11Speed7500rpmCapacity40 TPHInlet temp of steam475 CBleed temp of steam254 COutlet temp of steam170 CInlet pressure of steam63 kg/cm²Bleed pressure of steam 7.0 kg/cm²Outlet pressure of steam 2.5 kg/cm²GRAPH:High calorific value Vs moisture rate in %V. RESULTS AND DISCUSSIONGRAPH:Low calorific value Vs moisture rate in %FORMULAE USED:01. Boiler EfficiencyHeat absorberd by the steamȠboiler Heat liberated by the combustion of fuelmass of fuel usedMw03. Ma Moil04. H3 hsup hg Cps(tsup – ts)05. High calorific valueHCV (brix%sample))06. Low calorific value:07. LCV %sample))TABULATION:STEAM AND BAGASSE FLOW RATE OF THECalorific value are obtained from calculation depends uponthe moisture% sample, ash % sample, brix % samplesampl sampl 6821.314125.5Volume 6, Issue 07moisture rate in %ma(h3 h1)% Ƞboiler 100𝑐.𝑣02. Actual Evaporationmass of steam generatedma BOILER:CALCULATE THE EFFICIENCY OF BOILER BEFOREREDUCES THE MOISTURE IN BAGASSE:During the test of an bagasse fired water tubeboiler the following data were observed shown in table:10.2SteampressureSteamgeneratedperminuteFeed watertemperatureQualityofsteamBagasse firedperminute64.75barabs40000kg105 C99%dry20000kgPublished by, www.ijert.orgCalorificvalue ofbagasse in50%moisture8760.0kj/kg of fuel5
Special Issue - 2018International Journal of Engineering Research & Technology (IJERT)ISSN: 2278-0181ICONNECT - 2k18 Conference ProceedingsCalculate:% Ƞ boilerBoiler efficiency:ma(h3 h1)𝑐.𝑣 100MwActual evaporation:Ma MfH1 h2 at the feed water temperature of 105 C (Fromtemperature based steam table, S.I.UNITS R.S KHURMI)H1 445.968 kj/kgFrom pressure based steam tableAt 64.75 barHg 2779.7 kj/kgTs 280.5 CTsup 485 Ch3 hsup hg Cps (tsup-ts)h3 2779.7 2.41 (485-280.5)H3 3387 kj/kg40000From pressure based steam tableAt 64.75 barHg 2779.7 kj/kgTs 280.5 CTsup 485 CMa 16000Ma 2.5 kg/kg of fuelh3 hsup hg Cps (tsup-ts)h3 2779.7 2.41 (485-280.5)H3 3387 kj/kgȠboiler 68.58 atioSteamTemperature( C)SteamPressure(Bar)FeedwaterTemperature( .44100.11100.7798.79100.22400002(3387 445.968)8760.08760.0 100GRAPH:Efficiency Vs moisture rate in %Ma 20000Ma 2 kg/kg of fuelȠboiler 2.5(3387 445.968)moisture rate in %SteamflowRate(tons/hrs.)Ƞboiler Axis Title 100Ƞboiler 67.41 %CALCULATE THE EFFICIENCY OF BOILER AFTERREDUCES THE MOISTURE IN BAGASSE:During the test of an bagasse fired water tubeboiler the following data were observed shown in tableSteampressureSteamgeneratedperminuteFeed watertemperatureQualityofsteamBagasse firedperminute64.75barabs40000kg105 C99%dry16000kgCalorificvalueofbagasse in50%moisture10720.5kj/kg of fuelCalculate:01. Boiler efficiencySOLUTIONS:Boiler efficiency:% Ƞboiler ma(h3 h1)𝑐.𝑣 100MwActual evaporation: Ma MfH1 h2 at the feed water temperature of 105 C (Fromtemperature basedsteam table,S.I.UNITS R.SKHURMI)H1 440.15 kj/kgVolume 6, Issue 07VI. CONCLUSIONMill wet bagasse contains about 50% moisture. Thecalorific value of mill wet bagasse is 8760.0 kj.kg or 2280kcal/kg. Useof driers to reduce the moisture content inbagasse before it’s burnt, is regarded as a simple energyconservation measure. This bagasse drying system can alsouse the waste heat from the boiler flue gases for its partialheat requirement.That the co-generation plant attached to a sugarfactory can generation 2.20kgs of high pressure steam perkg bagasse and 4.40kgs of steam or required togenerate1KWH of power in the condensing mode.Hence 2kgs of saved bagasse can generate1KWH of power or 200kgs of saved bagasse per ton cangenerate 400KWH of power. A bagasse drier plant of 100tons per hrs. can save 20 tons of bagasse per hrs. or 450tons per day or 72000 tons per year on 160 days ofworking, which is equal to 3.6 core units of electricity peryear.Published by, www.ijert.org6
Special Issue - 2018International Journal of Engineering Research & Technology (IJERT)ISSN: 2278-0181ICONNECT - 2k18 Conference Proceedings[5]REFERENCES[1][2][3][4]Indian standards IS 6997- 1973. Test code for sugarcanecrusers.pressure and temperature are taken as reference from steamtables (S.I.UNITS R.S.KHURMI).gray MR corcoran WH, Gavalas GR. Pyrolysis of woodderived material, effects of moisture and ash content, industrialengineering chemistry, process designand development 1985:24: 646-51.Banerjee, R. and pandey, A. Bio-industrial application ofsugarcane bagasse. A technology perspective, 2002, Int. sugarJourna.Volume 6, Issue 07[6][7][8][9]jones PJ. 1981. Down flow of gas-solids mixtures in bottomrestrained vertical standpipes, Ph.D. Thesis, Dept.of chem.Eng., university of Queensland, Australia.hugot,E. Hand Book of Cane sugar engineering 3ᵈ Edition.Elsier science publishers’ B.V., 1000 Aamsterdam,Netherlands. 1986 PP: 872-884.minhas, M.J boiler efficiency calculations for the new 35 tonsboiler at hussain sugar mill, jaranwala, and society of sugartechnologists. 1985PP:362-375.crawfoed ER. Proc. Qld. Soc. Sugar Cane Technol. Australia1954:21:P.132.Lois, J, Sugar cane and co-products. Proceedings of XXXIIATAM Convention, 2009, August.Published by, www.ijert.org7
in boiler efficiency and the increase in steam to bagasse ratio because of lower moisture content in bagasse. A typical indirect dryer for bagasse application can be a bin dryer. The large bin is kept vertical with large diameter (100 or150mm) pipes passing along the vertical axis at a pitc
