Abstract: This paper expounds the overhaul of the diesel hydrogenation unit and reciprocating compressor for supplemented hydrogen after 16,000 hours of operation. During the reassembly process, it is found that the center position of the crankshaft shifts in different directions after tightening the bolts between the compressor and the motor coupling. The dial indicator is used to detect the offset direction and offset of the crankshaft center. Through analysis and troubleshooting, it is found that the deformation of the spacer ring and excessive flatness are the main causes for the offset of the crank shaft center. Aiming at the problem of the spacer ring, the treatment measure of adopting machining method for grinding is proposed. After installing the processed spacer ring, the crank shaft center no longer offsets and the installation technical requirements are met. This provides guarantee for the safe startup of the compressor.

Key words: reciprocating compressor, crank shaft, central deviation, treatment