The development of a wax layer on the interior wall of a circular pipe transporting heated oil

The development of a wax layer on the interior wall of a circular pipe transporting heated oil: the effects of temperature-dependent wax conductivity

“…This model has had further recent support in the independent works in [3] and [4]. 1 In [1], a thermal model for the deposition of paraffinic wax on the inside of the pipe wall was proposed. The principal hypothesis introduced in [1] is that the key mechanism leading to wax deposition is a thermal phase change process.…”

“…The fundamentals in this model are based on the assumption that the wax layer forms on cooling, as a thermal phase change from the dissolved wax in the hot oil, and therefore that the dynamics of the wax layer are dictated by thermal energy balances. The associated mathematical model was both formulated and analysed in detail in [1]. The outcomes were encouraging, in that a number of key observations in the wax layer deposition process, which were at odds with the historic material diffusion mechanism, were now fully accounted for in the thermal phase change model.…”

“…In oil field operation, it is generally required that oil is transported in long sea bed pipelines. In a recent paper [1], one of the main undesirable features for pipeline oil transportation, namely the formation of paraffinic wax deposits on the inside of the pipe wall, was considered. This wax deposit happens when the temperature of the pipe wall falls below the wax solidification temperature, generally in the range 35-40 • C, but this can be in a wider range of 20-60 • C, when dealing with real crude oils, rather than experimentally controlled oils.…”

“…Notably, the accumulation of a wax deposit on a pipe wall effectively reduces the inner diameter of the pipe, which lessens the transport capacity of the pipe for a given driving pressure. A more detailed discussion of this phenomena is given in [1]. In particular, [1] was concerned with the introduction of a thermal phase change model (first proposed by Schulkes in [2]) to capture the fundamental mechanism in the wax layer deposition process accurately.…”

“…A more detailed discussion of this phenomena is given in [1]. In particular, [1] was concerned with the introduction of a thermal phase change model (first proposed by Schulkes in [2]) to capture the fundamental mechanism in the wax layer deposition process accurately. The fundamentals in this model are based on the assumption that the wax layer forms on cooling, as a thermal phase change from the dissolved wax in the hot oil, and therefore that the dynamics of the wax layer are dictated by thermal energy balances.…”