A process engineer from one of our clients contacted MSC regarding a persistent issue with a steam pressure valve. The problem had become a single point of failure for the facility, and production interruptions could no longer be tolerated.
The steam back pressure regulating control valve played a critical role in plant operations. It fed low-pressure steam (15 psi) from a high-pressure steam condensate flash tank to several large heated jacketed process tanks, essentially functioning as a steam economizer utilizing excess process steam.
Periodically, the valve would stick in the fully open position, causing steam to vent continuously to the roof for hours. This created a deafening whistle and depleted the boilers of condensate, leading to boiler shutdowns due to low water levels and halting plant operations.
The problem had persisted for an extended period, occurring sporadically about twice a month despite multiple repair attempts over the past year. The facility had adapted by resetting the valve, located 16 feet off the ground, using a dedicated scissor lift.
MSC visited the site to assess the situation. Our service technician inspected the back pressure regulating valve and reviewed steam pressure trend logs and process conditions during problem occurrences with the plant engineer. After a thorough inspection of the valve and its pilot sensing line, we consulted the valve manufacturer's application engineer to review the operation, maintenance, design, and proper application of the valve.
Our detailed analysis revealed that during periods of low steam demand at the tanks, excessive back pressure would build up and need to be relieved. We determined that the existing mechanical back pressure valve and its discharge line were undersized and unsuitable for handling these conditions.
Based on our findings, MSC recommended installing a high-quality 4-20mA pressure transmitter, a larger control valve with feedback positioning, and an enlarged discharge line to the roof. With these changes implemented, followed by proper commissioning, the new electronic back pressure regulating valve performed flawlessly under all process scenarios. As a result, the client's production interruptions were eliminated, and the facility's efficiency significantly improved.
This project illustrates the value of thorough analysis and expert consultation in addressing complex industrial challenges. The implemented solution not only resolved the immediate issue but also enhanced the overall reliability of the client's steam system. MSC is pleased to have contributed to improving our client's operational efficiency through this project.
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