Process compressors used in the process industry (for example in the liquefaction, rectification and with chemical reaction of technical gases) have to fulfill demanding requirements in relation to performance and reliability.
Natural gas is a very important resource in the process industry. Its transport in gas pipelines or by tankers in the form of liquid natural gas, also its underground storage requires special natural gas compressors .
Preferably executions of process compressors in vertical and horizontal boxer design are being used, which fulfil the requirements of a specific standard for the oil and gas industry API 618, .
The throughput amounts up to 100000 m3h-1(related to standard condition), the discharge pressures up to 100 MPa (for specific applications up to 360 MPa).
The driving mechanisms are carried out in various sizes and with different number of cranks. They are designed for minimum deflection and the distance between the cylinders is kept to a minimum. The mean piston velocity goes up to 6 ms-1. The boxer design can achieve a full balance of mass forces and torque, if the design includes at least two pairs of cranks.
The cylinders are typically double acting and water-cooled. In the low-pressure stages, big compressor valves with sufficiently large valve chambers are necessary. This can more easily be done in boxer compressors. A pressure packing seals the working chamber at the crank side. The cylinder is connected to the crankcase via a distance piece, which transmits forces and centres the cylinder.