Petrochemical refineries in Northern Alberta rely on seal support systems to keep pumps working efficiently and safely and to prevent leaks. A seal support system leak, whether slow or catastrophic, can lead to unplanned downtime or unsafe conditions, including toxic fumes, flammable vapors, or spills, so it’s important to troubleshoot leaks as soon as they’re detected.
Mechanical seal failures are a leading cause of unplanned downtime, especially in older plants. In many cases, it’s aging seal support systems that cause the seal failure. Even a seemingly minor seal support system leak can eventually compromise the seal chamber environment and lead to mechanical seal failure.
When mechanical seal failure results from a seal support system leak, it may begin as imperceptible vaporization across the seal and, if not addressed, evolve into a catastrophic failure. In this post, we’ll look at the four most common causes of a seal support system leak and how to prevent them.
As seal support systems age, engineers often replace parts, modify fittings and tubing, and make minor customizations to keep the system running. While this may temporarily extend the system’s life, overall system performance declines. Standard seal support systems may also need modifications to fit the available space and infrastructure. In these situations, any compromises or shortcuts can cause reliability issues in the future. The inability to maintain pressure or temperature requirements can damage mechanical seals over time and cause leaks.
Use maintenance records to identify seal support systems that are aging or have a history of modifications. Specifically, look for corrosion of components, improperly torqued fittings, temporary fixes like PTFE tape, kinked or degraded hoses supplying external barrier fluids or gases, and tubing walls eroded by particulates.
Even high-quality seal support systems need regular preventive maintenance to keep running efficiently. With thousands of pumps to maintain and decreasing budgets, it can be challenging to consistently apply preventive maintenance. However, infrequent maintenance and inspection schedules can cause temperature, pressure, flow, or reservoir level anomalies that indicate a risk of a seal support system leak to go undetected.
Preventive maintenance schedules are critical in preventing seal support system leaks. Petrochemical plants with instrumented pumps and automated pressure and temperature monitoring are even better positioned for early identification and remediation of mechanical seal leakage causes.
Ideally, the mechanical seal and support system match the process needs and are never run significantly above or below the best efficiency point. In the real world, however, inconsistent operating conditions are common in most petrochemical plants. Fluid composition, pressures, and temperatures may vary significantly. Unexpected shutdown of upstream processes may even lead to dry running, which almost certainly leads to failure.
Changes to the process fluids, like increasing volumes of sour crude, may take a greater toll on seals and seal support systems than when they were originally implemented. Inadequate cooling, increased particulates, or higher fluid pressure can stress seal support systems that were not designed for those conditions, potentially leading to a seal support system leak.
Consult with a seal support systems specialist experienced with API 682 plans to evaluate your process and determine where seal support system upgrades or component replacements are needed to ensure seal support systems meet the current process requirements.
Ideally, seal support systems should be designed and situated to minimize the effects of vibrations from the pump or other sources. However, infrastructure constraints don’t always make this possible. In these cases, vibration can affect the system’s integrity over time and cause a seal support system leak.
If maintenance records for critical pumps indicate a history of vibration problems, work with your rotating equipment engineers and a local vendor to diagnose the issues and implement measures to minimize or eliminate them. By being proactive, a vibration-related seal support system leak can be prevented.
Edmonton Valve & Fitting is the ideal local partner to help assess the reliability of your seal support systems. If you have a seal support system leak, our Field Advisors have years of experience troubleshooting seal support system leaks and can perform an onsite consultation to help diagnose the problem. We can also perform a full evaluation of your current systems and recommend improvements to proactively prevent leaks and ensure optimal pump performance.