Abstract: The feed gas compressor of a 140,000 m3/h (standard state) hydrogen production & PSA unit is a 2D12591/639BX reciprocating compressor manufactured by Shenyang Blower Works Group Corporation. During its operation, the settlement displacement monitoring probe on the secondary piston rod is prone to contact wear with the piston rod, resulting in frequent replacement of the displacement monitoring probe and the compressor is therefore unable to operate continuously for a long period of time. During a recent replacement of the monitoring probe, it was found that the secondary piston rod was in contact with the inner ring of the middle body stuffing box cover, causing damage to both the upper surface of the piston rod and the inner ring of stuffing box cover due to friction. After disassembling the compressor for inspection, two problems were found: one is that the horizontal inner diameter of the middle position of the secondary cylinder liner deviates too much from the standard value, resulting in too small the gap between the middle support ring of the piston and the inner wall of the cylinder liner; and the other is that the overall tilt of the secondary cylinder and the crosshead slide exceeds the standard value. Aiming at the above problems, three measures for improvement were proposed, namely, replacing the secondary cylinder liner, readjusting the tilt amount of the secondary cylinder during installation, and periodically flushing the cooling jacket of the cylinder with clean water at a slightly higher pressure. After taking these measures, the monitoring data of the compressor has been back to normal and the operating condition has been good.

Key words: hydrogen production & PSA Unit, reciprocating compressor, displacement probe, piston rod, cylinder liner, support ring