The heat tracing issue for large-diameter crude oil transport pipelines

The heat output of a constant-power electric heating strip remains stable and is proportional to its length; the longer the heating strip used, the greater the total power output. When electric heating tapes are installed intersectingly, the temperature of the local pipelines may exceed their maximum tolerance level, which can affect the quality of the oil. Moreover, if any part of the electric heating tape is damaged, it will impact the proper functioning of other areas as well. Furthermore, constant-power heat tracing strips are also limited by the length of the sections, resulting in low utilization efficiency. However, its design and selection are relatively convenient, with lower initial investment, and it is still widely used today. Variable-power heat tapes generate heat throughout their entire length, allowing for arbitrary overlapping; moreover, their length can be adjusted during installation to minimize unnecessary waste. Furthermore, the electric heating strip is composed of numerous parallel structures, so even if there is local damage, it does not affect the operation of the other parts. The performance of self-limiting electric heat trace heating is determined by the PTC material used in its manufacture; the heating temperature is limited, and the manufacturing capabilities also restrict its length (usually less than a kilometer). For several years, self-limiting electric heat tracing tapes have been widely used in domestic and international applications for transporting crude oil over short distances at low heating temperatures.