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Flow modeling of molten asphalt in an undersea pipeline
A time dependent computational fluid dynamics (CFD) model was used to simulate molten asphalt flow through a cold pipeline. Molten asphalt was to be off-loaded from a tanker by an undersea pipeline to an onshore facility. The pipeline was approximately 1.5 miles (2.3 km) in length and had an ID of 23 inches (0.584 m) surrounded by several insulating layers. The unheated pipeline was initially filled with a middle weight oil termed 'cutter' which was at the ambient water temperature 55 degree F (12.8 C). The cutter would be displaced by molten asphalt (30 grade) which was initially at 250 degree F (121.1 C). This was to be pumped at a rate of 5,000 bbl/hr (1,041 m3/hr) for a period of 10 hrs. The asphalt temperature-viscosity curve is characterized by essentially solidification around 195 degree F (90.56 C) although there is no latent heat of fusion associated with an actual phase change. The asphalt viscosity curve is presented as figure 1. The factors might suggest the asphalt would solidify immediately upon entering the pipeline, however, there are other contravening conditions. The asphalt is an excellent insulator and once a solidified layer forms on the pipeline walls the interior should not lose a great deal of heat; possibly allowing a core of asphalt to flow completely through the pipeline. Concern was expressed however as once sufficient cooling & solidification occurred to impede the flow of the leading 'slug' (e.g. first 30 ft or 9m) of asphalt, continued heat loss would thus solidify the entire asphalt filled length of undersea pipeline. To determine which effects would prevail and whether the heat loss from the moving asphalt would be acceptable, Flow Simulations, Inc, of Houston Texas was asked to model this problem using CFD.
Flow modeling of molten asphalt in an undersea pipeline
A time dependent computational fluid dynamics (CFD) model was used to simulate molten asphalt flow through a cold pipeline. Molten asphalt was to be off-loaded from a tanker by an undersea pipeline to an onshore facility. The pipeline was approximately 1.5 miles (2.3 km) in length and had an ID of 23 inches (0.584 m) surrounded by several insulating layers. The unheated pipeline was initially filled with a middle weight oil termed 'cutter' which was at the ambient water temperature 55 degree F (12.8 C). The cutter would be displaced by molten asphalt (30 grade) which was initially at 250 degree F (121.1 C). This was to be pumped at a rate of 5,000 bbl/hr (1,041 m3/hr) for a period of 10 hrs. The asphalt temperature-viscosity curve is characterized by essentially solidification around 195 degree F (90.56 C) although there is no latent heat of fusion associated with an actual phase change. The asphalt viscosity curve is presented as figure 1. The factors might suggest the asphalt would solidify immediately upon entering the pipeline, however, there are other contravening conditions. The asphalt is an excellent insulator and once a solidified layer forms on the pipeline walls the interior should not lose a great deal of heat; possibly allowing a core of asphalt to flow completely through the pipeline. Concern was expressed however as once sufficient cooling & solidification occurred to impede the flow of the leading 'slug' (e.g. first 30 ft or 9m) of asphalt, continued heat loss would thus solidify the entire asphalt filled length of undersea pipeline. To determine which effects would prevail and whether the heat loss from the moving asphalt would be acceptable, Flow Simulations, Inc, of Houston Texas was asked to model this problem using CFD.
Flow modeling of molten asphalt in an undersea pipeline
Krawczyk, J. (author)
1998
Seiten
Conference paper
Storage medium
English
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