Compressors staged operation

The main power source is a 2,200 kW rated motor, which drives two high-speed pinions through integral gears. The first stage of the compressor operates at 17,900 rpm, while the second and third stages operate at 21,800 rpm. The unit is controlled by a local control system, but operators can also monitor the operating parameters from the plant control room. 

The large frontal areas of these units reduce the inlet velocities, thus reducing air noise. The pressure rise in each compressor stage is reduced, creating a large, stable operating zone. 

In practice the ratios for each stage may not work out to be exactly the same. This does not keep the compressor from operating satisfectorily as long as all other factors are handled accordingly. 

Head per section is another important parameter, as the smaller the number of impellers per section, the higher the head required per compressor stage. This leads to higher rotative speeds and operation at higher Mach numbers, which in turn, tends to limit the operating range, flatten the head rise characteristic, and reduce efflciency. ... 

Natural gas (CH4) is transported through a 6 in. ID pipeline at a rate of 10,000 scfm. The compressor stations are 150 mi apart, and the compressor suction pressure is to be maintained at lOpsig above that at which choked flow would occur in the pipeline. The compressors are each two stage, operate adiabatically with interstage cooling to 70°F, and have an efficiency of 60%. If the pipeline temperature is 70°F, calculate ... 

Each compressor stage in the MUG compressor unit operates adiabatically. If ideal gas behavior is... 

Centrifugal compressors can operate at speeds from 9,000 to 50,000 rpm, with single-stage compression ratios from 1.2 to 9, and efficiencies from 30 to 85%, depending upon the specific design and application. 

The high-pressure dryer has also found appHcation in high-pressure compressed air systems onboard US Navy vessels [61]. These dryers are typically operated between compressor stages at 30 to 70 bar pressures and the dry product returned to the next compression stage for final boost to the 200 to 330 bar receiver pressure. 

A regulation of the operating liquid temperature should take place in principle on the basis of the ring liquid escaping on the pressure side of the compressor stage, since otherwise energy inputs by gas and vapour as well as the variability of the amount of liquid remain unconsidered. 

For gas recompression operations dry-running piston machines (non-lubricated) must be used. The compression ratio during the recompression operation will typically increase from a very low value to about 20 as the inlet pressure progressively decreases. Two or three compressor-stages with intercooling are therefore usual. At the end of the recompression operation the compressor inlet pressure may be as low as 3 bar, while the outlet is at 70 bar. The volume flow (measured at NTP) may be as high as 30 000 m /h. 

Turbo compressors are most economical when they operate with large amounts of chlorine. Each unit compresses up to 1800 t/d. In multiple-stage operation, pressures up to 1.6 MPa are reached. Labyrinth seals are used on the high-speed shafts. Require-... 

The rate of gas production is 20 000 m /hr per gasifier, hence with all 6 gasifiers running the gas production rate will be 120000 m /hr. The rate of the downstream gas compressor stage is to be controlled to match the inflow of gas so that the level of the gas holder is stabilized at typically 50%. The EUC control system comprises an automatic level control loop operating on the input control valves of the compressors supported by manual controls that allow the operator to decide if one or two compressors are to be run to balance the load. 

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