The Problem
During the fabrication and installation process at an LNG plant, lubrication oil supply and return lines are prone to accumulating harmful contaminants such as welding slag, metal shavings, dirt, water, and other environmental pollutants. If these contaminants are not effectively removed before system start-up, they can cause significant damage to journal bearings and hinder the system’s ability to maintain the OEM’s ISO 4406 17/15/12 standard for fluid cleanliness.
The Solution
Chemical Cleaning
To expedite the flushing process, chemical cleaning was utilized on carbon steel piping using a simple pickle and passivation process. This included the use of degreasers, food-grade citric acid, soda ash, and sodium nitrite. Chemical cleaning was performed on various systems, including MRC Compressor Coolers (carbon steel tubing) and pre-filtration piping on refrigeration compressors.
High-Velocity Oil Flushing
To remove all contamination in the lube oil piping left from pipe fabrication and installation, high-velocity oil flushing (HVOF) was performed. This process involved the use of high flow flushing skids, oil heaters, high efficiency filtration media, stainless braided jumper hoses, pipe vibrators, compressed dry air, and 100 mesh flushing screens. HVOF was applied to various systems, including Siemens Centrifugal Boil Off Gas Compressors, Siemens Reciprocating Boil Off Gas Compressor, GM LM2500 Generators, GE Frame 7 Generators, GE Steam Turbines, Technical America Refrigeration Compressors, Regen Gas Lube Oil Pumps 3HP, Baker Hughes MRC, and Baker Hughes Booster Gas Compressors. After two consecutive clean screens were achieved, the reservoir was pumped down, and a confined space entry cleaning of the system reservoir was performed to remove all gross contamination from the tank. The oil was then pumped back into the system and filtered until an NAS 1638 Class 6 / ISO 4406 17/15/12 cleanliness code was achieved.
Customer Quote
“Gentlemen, I wanted to let you guys know what a fantastic job your crew and company are doing here at CPLNG. These guys are committed to safety, environment, and quality. Our safety team went out and did a safety audit of the lube oil flushing operation. For safety to not have a single comment other than, ‘Keep up the good work!’ says a lot. You guys keep up the great work. “
CSU Mechanical Lead – Kiewit Engineering Group, Inc.