Page 237 - Reciprocating Compressors Operation Maintenance

222 Reciprocating Compressors: Operation and Maintenance

Plant C, however, was an anomaly. There, the labyrinth compressors
exceeded the reported average cost of conventionally lubricated units in
plants owned by the same corporation by about 18%. Plants in this study
that were owned by other corporations spent at least 1.33 times the base
amount of roughly $ll/kW per year (for example, the amount spent for
maintenance of labyrinth machines at Plant A)» and as much as three
times the base amount for maintenance of conventional reciprocating
compressors.
The number of downtime events per year (see Table 3-14), compressor
availability (see Figure 3-68) and consumption of spare parts (see Table
3-15) were also studied. The data in Table 3-14 were gathered from six
plants in North America and Europe belonging to the same corporation.
For the two plants reporting the most frequent downtime events (Plants B
and C), the actual availability for each machine was calculated (Figure
3-68); however, downtime data on the very troublesome ring-equipped
non-lubricated reciprocating compressors originally installed at Plant B
were unavailable. Only one of the five compressors (which was at Plant
B) exhibited an availability below that reported for conventional lubricat-
ed reciprocating compressors in the U.S. Gulf Coast plants (for example,
96.36% vs. 98.5%). All other machines exceeded the average.

FIGURE 3-68. Availabilities of individual labyrinth-piston compressors
reported by two North American plants (Source: Block, H. P, "Consider a Low
Maintenance Compressor," Chemical Engineering, July 18, 1988).