Gas Movers and Compressors Fans Centrifugal blowers and compressors Rotary blowers and compressors...
Embed Size (px)
Transcript of Gas Movers and Compressors Fans Centrifugal blowers and compressors Rotary blowers and compressors...
Gas Movers and CompressorsFansCentrifugal blowers and compressorsRotary blowers and compressorsReciprocating compressorsEjectorsDischarge pressure > 2 bara = compressor
Gas Movers and CompressorsWhere are they needed?
Gas Movers and CompressorsWhere are they needed?utility air, steamhigh pressure reactor;refrigerationheat pumpsfeed to furnacesQuestion: When is redundancy necessary?
FansLow pressure (ca 101 kPa) and low P (1-15 kPa)High volume flow to 500 std m3/sEfficiencies of 65-80%Variety of materialsFour typesCentrifugal Fan
Centrifugal CompressorsPressure to 700 atm, 1.2-1.4 compression ratio/stageUp to 8 stages per casingVolume flow to 200 std m3/sEfficiencies of 70-80%Favored choice for P < 15 atm What is the compression ratio?Outlet pressure/inlet pressure
Axial CompressorsPressures to 14 atmCompression ratio 1.4 per stage, up to 15 stages/casingHigh volume flow to 300 std m3/sEfficiencies of 80-85%Expensive, inflexible operationBase loads, utilities
Rotary CompressorsMedium pressure (to 10 atm) and compression ratio to 4!Low volume flow to 20 std m3/sEfficiencies of 60-80%Good for constant volume deliveryFour types listed in UlrichSliding vane compressor
Reciprocating CompressorsPressure to 3000 atm, compression ratio=4/stageUp to 8 stages per casingEfficiencies of 60-80%Expensive, but commonly used for high-pressure applications
All of this information is summarized in one table:consider the first half in detail
Radial FansAxial FansCentrifugalCompressors
Summary:Selection of EquipmentFans are for low P (101 kPa), low P (1-15 kPa)Blowers (centrifugal and rotary) are for moderate pressures, up to 1 MPaCompressors operate at 0.01 to 30 MPa depending on typeTurbo-expanders are like compressors running in reverse for power recovery
Summary: SelectionSelect based on:range of applicationlocationcostservice
Costing of Fans and CompressorsWhat is the size basis?For fans, the volumetric flow: P is lowFor compressors, power or shaft work: must be considered
Blowers and Compressors
Compressor CalculationsFluid Powerfor costingShaft Powerfor driverNon-ideal fluids:
Compressor Calculations (cont)Ideal Gas:Temperature increases with compression compression ratio p2/p1 < 4 for each stage
Example CompressorHydrogen compressor, from 1 MPa at 25 C to 20 MPaFlow rate of 0.123 kg/sWhat is the bare module cost?