I know this title comes across as a cryptic comment. But, it’s also a reminder that removing seemingly useless components associated with plant-equipment systems can have unforeseen (albeit not unforeseeable) consequences. Remember, too, that all effects have causes, and causes and effects obey the laws of physics.
The truth of the above was proven in regard to compressor equipment when, during a scheduled plant turnaround in the Houston area, a mid-level manager pointed to steam tracing that had not been in use over the past 10 or 12 years. The steam trace tubing had been wrapped around the pipe leading from a reciprocating-compressor-moisture-disengaging drum to the inlet flange on the first stage of the machine. Insulation had been applied as part of the original installation and, it seemed, was no longer needed.
There was absolutely no doubt that steam tracing had been disconnected at least 10 years prior: Open steam inlet and outlet connectors were clearly visible and moved in the strong breeze occasionally experienced near the Bayou City. As part of the final cleanup touches, a group of contractors removed the obviously unnecessary and, by that point in time, rather ugly insulation.
Fast forward to a nice day in late spring when the reciprocating compressor was recommissioned. It ran flawlessly for several sunny days. Then a serous rainstorm hit the Houston Ship Channel area. That’s when the recommissioned unit suffered a massive failure: The first stage of compression showed signs of liquid slugging, and a piston rod was bent.
What had happened?
For about 10 years, and even without steam tracing, the gas composition and its hot temperature had allowed the saturated gas to remain just that: a gas. The “ugly” insulation had kept the gas hot enough to cause no harm. However, without insulation and with the connecting pipe being cooled by a downpour, massive amounts of condensate had formed and entered the compressor’s first-stage cylinder.
There’s a moral to this story. Whether we like it or not, the laws of physics are not to be fooled with.TRR
Editor’s Note: Click Here To Download An Updated (May 2020) List Of Heinz Bloch’s 22 Books
ABOUT THE AUTHOR
Heinz Bloch’s long professional career included assignments as Exxon Chemical’s Regional Machinery Specialist for the United States. A recognized subject-matter-expert on plant equipment and failure avoidance, he is the author of numerous books and articles, and continues to present at technical conferences around the world. Bloch holds B.S. and M.S. degrees in Mechanical Engineering and is an ASME Life Fellow. These days, he’s based near Houston, TX. Email him directly at [email protected].
Tags: reliability, availability, maintenance, RAM, professional development
