Tracing the Causes of Heat Maintenance Issues

Steam tracing systems are used throughout oil and gas and chemical facilities. Common problems, such as steam locking caused by incorrect installation, can hinder the performance of these systems.

▲Figure 1. This pipe has multiple steam tracing lines installed to obtain high heat transfer.

Steam tracing is a system of tubing or jacketing laid along the outside of piping and equipment (beneath the insulation) to maintain or raise the temperature of the fluid within (Figure 1).

Chemical process industries (CPI) facilities often use steam tracing to maintain a product’s desired viscosity and control instrumentation reliability. Thermal maintenance is critical to production, because it prevents fluids from becoming too cool, which can change the viscosity of the stream and even lead to product solidification and stagnated flow. Steam tracing is also used to keep instrument boxes warm, which improves instrument accuracy.

Poor performance of steam tracing systems can often be attributed to ineffective design or routing of tracing, or to steam traps that are not suited to the application. If heat transfer from tracing is inadequate or a steam trap within the system is not performing, products can solidify (i.e., freeze up) and cause a plant shutdown.

CPI facilities pay significant attention to equipment and piping, but often treat steam tracing lines like simple plumbing. Plant designers often neglect to provide detailed drawings for the installation of steam tracing lines in new plant construction, leaving the design up to the installation contractor. But in a typical refinery or chemical plant, 50–80% of the facility’s steam traps can be found on steam tracing lines. This article reviews some common mistakes and problems encountered in heat tracing design and operation, and discusses how to improve existing steam tracing installations.