Reciprocating compressor cooling

While the foregoing examples have dealt with applications on centrifugal pumps, the same sort of analysis can be made for reciprocating pumps, reciprocating compressors, or other rotary users hke cooling-tower fans. 

Another feature necessary to the reciprocating compressor is cylinder cooling. Most process compressors are furnished with water jackets as an integral part of the cylinder. Alternatively, particularly in the smaller size compressors, the cylinder can be designed for air cooling. 

A V-belt-driven, force-fed oil lubrication system is used on water-cooled compressors. Oil goes to both bearings and to several points in the cylinder. Ten times as much oil is recommended to lubricate the rotary cylinder as is required for the cylinder of a corresponding reciprocating compressor. The oil carried over with the gas to the line may be reduced 50 per cent with an oil separator on the discharge. Use of an aftercooler ahead of the separator permits removal of 85 to 90 per cent of the entrained oil. 

Estimate the work required to compress ethylene to 25 MPa in a two-stage compressor. A reciprocating compressor will be used. The gas is at an initial temperature of 15°C and is cooled to 25°C after the first-stage compression. 

Figure 7.18. Heavy-duty centrifugal, axial, and reciprocating compressors, (a) Section of a three-stage compressor provided with steam-sealed packing boxes (DeLaval Steam Turbine Co.), (b) An axial compressor (Clark Brothers Co.), (c) Double-acting, two-stage reciprocating compressor with water-cooled jacket and intercooler (Ingersoll-Rand Co.).

Therefore, negative pressure was decreased to reduce tramp air. Also, the operational reciprocating compressor was replaced by a centrifugal rotary screw type compressor. Further, ash build up on the boiler superheater tubes was a problem, impeding heat transfer to cool down the flue gas. This problem was resolved by using acoustics to cause the ash to fall off the superheater and economizer tubes. This allowed lower fuel consumption, resulting in decreased NOx emissions.1... 

The reciprocating compressor was one of three identical units mounted side-by-side under a covered shed in an open-air chemical plant. These compressors were capable of compressing about 50 tons per day of acidic gases from 25 psig to 175 psig. The compressor operated at 300 RPM and was driven by a 150-horsepower electrical motor. This 30-year-old compressor was initially designed with a well water cooling flow on the jacket. Initially a 3/4-inch valve supplied well water. The water flowed out of the compressor jacket and into a funnel, so the operator had a visual indication of flow and no provisions to block the water. [3]... 

Crystallizer, vacuum batch, c.S. Compressor, reciprocating, air cooled, two-stage, 500-7000 ft3 0.37... 

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