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Compressors

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Compressors

  1. 1. 1Training Session on Air CompressorTraining Session on Air CompressorCompressors &Compressors &Compressed AirCompressed AirSystemsSystems
  2. 2. 2Training Agenda: CompressorTraining Agenda: CompressorIntroductionTypes of compressorsAssessment of compressors andcompressed air systemsEnergy efficiency opportunities
  3. 3. 3• Compressors: 5 to > 50,000 hp• 70 – 90% of compressed air is lostSignificant InefficienciesIntroductionIntroduction
  4. 4. 4(CompressedAir)• Electricity savings: 20 – 50%• Maintenance reduced, downtime decreased,production increased and product qualityimprovedBenefits of managed systemIntroductionIntroduction
  5. 5. 5• Intake air filters• Inter-stage coolers• After coolers• Air dryers• Moisture drain traps• ReceiversMain Components in CompressedAir SystemsIntroductionIntroduction
  6. 6. 6Training Agenda: CompressorTraining Agenda: CompressorIntroductionTypes of compressorsAssessment of compressors andcompressed air systemsEnergy efficiency opportunities
  7. 7. 7Two Basic Compressor TypesTypes of CompressorsTypes of CompressorsType ofcompressorPositivedisplacementDynamicReciprocating Rotary Centrifugal Axial
  8. 8. 8• Used for air and refrigerant compression• Works like a bicycle pump: cylinder volume reduceswhile pressure increases, with pulsating output• Many configurations available• Single acting when using one side of the piston, anddouble acting when using both sidesReciprocating CompressorTypes of CompressorsTypes of Compressors
  9. 9. 9Screw compressor• Rotors instead of pistons: continuousdischarge• Benefits: low cost, compact, low weight,easy to maintain• Sizes between 30 – 200 hp• Types• Lobe compressor• Screw compressor• Rotary vane / Slide vaneRotary CompressorTypes of CompressorsTypes of Compressors
  10. 10. 10• Rotating impellertransfers energyto move air• Continuous dutyCentrifugal CompressorTypes of CompressorsTypes of Compressors• Designed oilfree• High volumeapplications> 12,000 cfm
  11. 11. 11• Efficiency at full, partial and no load• Noise level• Size• Oil carry-over• Vibration• Maintenance• Capacity• PressureComparison of CompressorsTypes of CompressorsTypes of Compressors
  12. 12. 12Training Agenda: CompressorTraining Agenda: CompressorIntroductionTypes of compressorsAssessment of compressors andcompressed air systemsEnergy efficiency opportunities
  13. 13. 13• Capacity: full rated volume of flow ofcompressed gas• Actual flow rate: free air delivery (FAD)• FAD reduced by ageing, poor maintenance,fouled heat exchanger and altitude• Energy loss: percentage deviation of FADcapacityCapacity of a CompressorAssessment of CompressorsAssessment of Compressors
  14. 14. 14• Isolate compressor and receiver and close receiveroutlet• Empty the receiver and the pipeline from water• Start the compressor and activate the stopwatch• Note time taken to attain the normal operationalpressure P2 (in the receiver) from initial pressure P1• Calculate the capacity FAD:Simple Capacity Assessment MethodAssessment of CompressorsAssessment of CompressorsP2 = Final pressure after filling (kg/cm2a)P1 = Initial pressure (kg/cm2a) after bleeding)P0 = Atmospheric pressure (kg/cm2a)V = Storage volume in m3 which includes receiver,after cooler and delivery pipingT = Time take to build up pressure to P2 in minutes
  15. 15. 15Compressor EfficiencyAssessment of CompressorsAssessment of Compressors• Most practical: specific powerconsumption (kW / volume flow rate)• Other methods• Isothermal• Volumetric• Adiabatic• Mechanical
  16. 16. 16Isothermal efficiencyP1 = Absolute intake pressure kg / cm2Q1 = Free air delivered m3 / hrr = Pressure ratio P2/P1Compressor EfficiencyAssessment of CompressorsAssessment of CompressorsIsothermal efficiency =Actual measured input power / Isothermal powerIsothermal power (kW) = P1 x Q1 x loge r / 36.7
  17. 17. 17Volumetric efficiencyD = Cylinder bore, meterL = Cylinder stroke, meterS = Compressor speed rpmχ = 1 for single acting and 2 for double acting cylindersn = No. of cylindersCompressor EfficiencyAssessment of CompressorsAssessment of CompressorsVolumetric efficiency= Free air delivered m3/min / Compressor displacementCompressor displacement = Π x D2/4 x L x S x χ x n
  18. 18. 18• Consequences• Energy waste: 20 – 30% of output• Drop in system pressure• Shorter equipment life• Common leakage areas• Couplings, hoses, tubes, fittings• Pressure regulators• Open condensate traps, shut-off valves• Pipe joints, disconnects, thread sealantsLeaksAssessment of CompressorsAssessment of Compressors
  19. 19. 19• Total leakage calculation:T = on-load time (minutes)t = off-load time (minutes)• Well maintained system: less than 10%leakagesLeak Quantification MethodAssessment of CompressorsAssessment of CompressorsLeakage (%) = [(T x 100) / (T + t)]
  20. 20. 20• Shut off compressed air operated equipments• Run compressor to charge the system to setpressure of operation• Note the time taken for “Load” and “Unload”cycles• Calculate quantity of leakage (previous slide)• If Q is actual free air supplied during trial(m3/min), then:Quantifying leaks on the shop floorAssessment of CompressorsAssessment of CompressorsSystem leakage (m3/minute) = Q × T / (T + t)
  21. 21. 21• Compressor capacity (m3/minute) = 35• Cut in pressure, kg/cm2 = 6.8• Cut out pressure, kg/cm2 = 7.5• Load kW drawn = 188 kW• Unload kW drawn = 54 kW• Average ‘Load’ time =1.5 min• Average ‘Unload’ time = 10.5 minExampleAssessment of CompressorsAssessment of CompressorsLeakage = [(1.5)/(1.5+10.5)] x 35 = 4.375 m3/minute
  22. 22. 22Training Agenda: CompressorTraining Agenda: CompressorIntroductionTypes of compressorsAssessment of compressors andcompressed air systemsEnergy efficiency opportunities
  23. 23. 23• Significant influence on energy useEnergy Efficiency OpportunitiesEnergy Efficiency Opportunities1. Location2. Elevation• Higher altitude = lower volumetricefficiency
  24. 24. 243. Air Intake• Keep intake air free fromcontaminants, dust or moist• Keep intake air temperature lowEvery 4 oC rise in inlet air temperature = 1%higher energy consumption• Keep ambient temperature low whenan intake air filter is located at thecompressorEnergy Efficiency OpportunitiesEnergy Efficiency Opportunities
  25. 25. 254. Pressure Drops in Air Filter• Install filter in cool location or drawair from cool location• Keep pressure drop across intake airfilter to a minimumEvery 250 mm WC pressure drop =2% higher energy consumptionEnergy Efficiency OpportunitiesEnergy Efficiency Opportunities
  26. 26. 265. Use Inter and After Coolers• Inlet air temperature rises at eachstage of multi-stage machine• Inter coolers: heat exchangers thatremove heat between stages• After coolers: reduce air temperatureafter final stage• Use water at lower temperature:reduce powerEnergy Efficiency OpportunitiesEnergy Efficiency Opportunities
  27. 27. 27• Higher pressure• More power by compressors• Lower volumetric efficiency• Operating above operating pressures• Waste of energy• Excessive wearEnergy Efficiency OpportunitiesEnergy Efficiency Opportunities6. Pressure Settings
  28. 28. 28a. Reducing delivery pressureOperating a compressor at 120 PSIG instead of 100PSIG: 10% less energy and reduced leakage rateEnergy Efficiency OpportunitiesEnergy Efficiency Opportunities6. Pressure Settingsb. Compressor modulation by optimumpressure settingsApplicable when different compressors connectedc. Segregating high/low pressurrequirementsPressure reducing valves no longer needed
  29. 29. 29d. Design for minimum pressure drop inthe distribution line• Pressure drop: reduction in air pressure fromthe compressor discharge to the point of use• Pressure drop < 10%• Pressure drops caused by• corrosion• inadequate sized piping, couplings hoses• choked filter elementsEnergy Efficiency OpportunitiesEnergy Efficiency Opportunities6. Pressure Settings
  30. 30. 30D. Design for minimum pressure drop inthe distribution lineEnergy Efficiency OpportunitiesEnergy Efficiency Opportunities6. Pressure SettingsTypical pressure drop in compressed air line fordifferent pipe size (Confederation of Indian Industries)
  31. 31. 317. Minimizing Leakage• Use ultrasonic acoustic detector• Tighten joints and connections• Replace faulty equipment8. Condensate Removal• Condensate formed as after-cooler reducesdischarge air temperature• Install condensate separator trap to removecondensateEnergy Efficiency OpportunitiesEnergy Efficiency Opportunities
  32. 32. 329. Controlled usage• Do not use for low-pressureapplications: agitation, combustion air,pneumatic conveying• Use blowers instead10. Compressor controls• Automatically turns off compressorwhen not neededEnergy Efficiency OpportunitiesEnergy Efficiency Opportunities
  33. 33. 339. Maintenance Practices• Lubrication: Checked regularly• Air filters: Replaced regularly• Condensate traps: Ensure drainage• Air dryers: Inspect and replacefiltersEnergy Efficiency OpportunitiesEnergy Efficiency Opportunities
  34. 34. 34Training Session on EnergyTraining Session on EnergyEquipmentEquipmentCompressors &Compressors &Compressed AirCompressed AirSystemsSystems
  • Dotsefamous

    Jan. 29, 2019
  • TlakaleKgoete

    May. 28, 2018
  • TutuTu1

    Aug. 27, 2017
  • CURTISARISTNEEQUAYE

    Jul. 17, 2017
  • RaviKiran256

    Mar. 25, 2015

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