Top Strategies for Refinery Winterization in Edmonton’s Process Plants

Controlling ambient parameters is central to ensuring a fluid system is running smoothly. If a drastic change in temperature occurs—and isn’t planned for—it can amplify the harmful effects of the fluid on its surrounding system. For example, corrosivity and pressure are positively correlated with an increase in temperature, and accelerated wear could arrest operations without immediate maintenance. Temperature swings in the opposite direction can be equally destructive; any time a fluid experiences a phase change in a container that it is not designed to facilitate, the potential for damage increases. 

In Edmonton, refinery winterization programs provide a necessary level of protection to equipment that might otherwise fail due to temperature extremes and resultant damage.

Insulated Traced Tubing Is at the Forefront of Refinery Winterization Programs

For lines exposed to winter temperatures well below freezing, insulation alone may not be enough. An active heating element can be used to prevent disruptions in tubing used to transport process media for analytical purposes. While freezing is the more catastrophic mode of failure, a decrease in viscosity due to a temperature drop can just as easily arrest operations and render a shutdown. The heating elements of the traced tubing come in two general styles:

• Electrical - A preferred option for long lengths of tubing that typically accompany sampling or impulse lines. Electrical trace lines have some additional control features that are not present in steam lines, such as trace self-regulation that lowers heat output as the bundle’s temperature rises and the ability to interface with an optional thermometer to regulate temperature semi-autonomously.
• Steam/Glycol - An alternative for areas where electrification may be harder to come by than process steam or glycol. Trace lines can be subdivided into light heat tracing, typically found in instrumentation and analyzation lines, and heavy heat tracing which is used to maintain process temperature or viscosity. Heavy traced tubes are able to accomplish a greater heating rate by having the trace line in direct contact with the tubing. However, the light heat trace is insulated separately from the tubing, resulting in less heat loss over longer distances. Finally, while steam is a more effective heating option than electrical, it can be the costlier choice.

Insulation and sealing are also important to the efficiency and longevity of heat-traced lines. Heat-shrink end- and entry-seal boots create waterproof seals when transitioning to or from enclosures. Preventing moisture ingress is especially important for electrical trace tubing, which could electrically short in the proximity of fuel sources.

Steam jacketed lines are also an option for winterization of piping. As opposed to heat traced lines where the fluid and heating element are in separate lines bundled together, steam jacketing has the fluid line directly encapsulated by the steam. This setup allows for an extremely large heat transfer surface, significantly increasing the thermal flux capability.

How Steam Traps Keep Steam-Powered Systems Flowing Smoothly

For every steam traced line in your system, steam traps will be a necessity. The steam trap is used in heating systems to separate between condensate and steam; they sit at a low point in the system to be able to effectively remove condensate and non-condensable gaseous mixtures. In fact, steam traps should be utilized every hundred feet of heated line or in the event of turns and elevation changes in the mainline. Further, steam traps should be present before any valves to remove condensate from the line—especially in the case of relief valves. This will help prevent the presence of a freeze leading to a rupture. 

Without appropriate condensate removal, it is possible that the condensate experiences enough acceleration in the piping to create water hammer, which can lead to significant damage to equipment as well as present a major hazard to operators. In the event of a realized water hammer in extreme weather conditions, there are likely to be additional knock-on effects within the system, such as increases in viscosity in process lines or perhaps freezing that leads to more rupture events. 

Best practices to ensure maximum condensate removal will rely on several factors:

• Intervals: Steam traps are most effective installed every hundred feet or so. This ensures the condensate does not have a large distance to build up volume and speed.
• Valves: Steam traps should be present before any pressure-relief, control, or closed manual valves. Doing so prevents the buildup of condensate and also protects the valve seat from erosion.
• Vertical pipeline shifts: To prevent condensate pooling due to gravity at the bottom of any vertically-oriented pipe, a steam trap should be used.

Additional Winterization System Preparations

Winterization is a wide-reaching process, and heat traced lines and steam trap implementation only cover a small portion of the necessary procedures to prevent downtime or system failure. Below is a noncomprehensive list of some additional miscellaneous processes to consider that help protect refineries against the extremes of Edmonton’s winter temperatures:

• Conduct Leak Detection and Repair (LDAR): Just as important as it is during more mild months to prevent fugitive emissions, leak detection and repair will be able to discover and correct any leaking pipeworks that could otherwise rupture further and experience system failure.
• Ensure steam trap functionality: A properly functioning steam trap helps to stop the transmission of unused steam into the drainage. If a steam trap fails open, steam can leak through, creating concerns of steam freezing on external surfaces and resulting in large icicles and poor visibility in parts of the plant.  
• Employ grab sampling: System models not explicitly designed to handle low temperatures can fail, and dead legs of the system could rupture if not purged beforehand.
• Develop equipment housing: For equipment located outdoors, temporary construction of a heated shelter may be necessary to prevent freezing and related complications.
• Take safety precautions: New and increased safety measures need to be taken to protect operators. Some, but not all of these improvements, would include utilizing temporary heaters instead of HVAC to maintain visibility indoors, having sand/gravel outside buildings by entrance and exit doors, and testing the backup generators prior to the winter season arriving in full swing.

Edmonton Valve & Fitting Can Brace Your Fluid System for the Most Taxing Season

When it comes time to begin your winterization preparation, consult with an Edmonton Valve & Fitting Field Advisor. Our Field Advisors have a wealth of experience in leak detection and repair, in addition to general fluid system knowledge, that they can apply to ensure your system is prepared for the rigors of winter. Whether you’re in need of a new part, or a helpful pair of eyes to analyze, assess, and redress your refinery winterization programs, look no further than Edmonton Valve & Fitting.