To maximize production and minimize pumping costs, crude oil is heated to reduce its viscosity during transportation from a production field. (1) Consider a pipe-in-pipe configuration consisting of concentric steel tubes with an intervening insulating material. The inner tube is used to transport warm crude oil through cold ocean water. The inner steel pipe ( ks = 40 W/m·K) has an inside diameter of Di,1 = 150 mm and wall thickness ti = 20 mm while the outer steel pipe has an inside diameter of Di,1 = 250 mm and wall thickness . Determine the maximum allowable crude oil temperature to ensure the polyurethane foam insulation ( kp = 0.0425 W/m·K) provides an external convection heat transfer coefficient of ho = 500 W/m2·K. The convection coefficient associated with the flowing crude oil is hi = 450 W/m2·K. (2) It is proposed to enhance the performance of the pipe-in-pipe device by replacing a thin ( ta =10 mm) section of polyurethane located at the outside of the inner pipe with an aerogel insulation material ( ka = 0.012 W/m·K). Determine the maximum allowable crude oil temperature to ensure maximum polyurethane temperatures are below tp,max = 70°C. Determine the convection heat transfer resistance on the inside of the pipe per unit length, in m·K/W. Determine the conduction resistance of the polyurethane per unit length without the aerogel, in m·K/W. Determine the conduction resistance of the polyurethane per unit length when aerogel is used, in m·K/W. Determine the maximum crude oil temperature if no aerogel is used, in °C. Determine the maximum crude oil temperature if aerogel is used, in °C.
To maximize production and minimize pumping costs, crude oil is heated to reduce its viscosity during transportation from a production field. (1) Consider a pipe-in-pipe configuration consisting of concentric steel tubes with an intervening insulating material. The inner tube is used to transport warm crude oil through cold ocean water. The inner steel pipe ( ks = 40 W/m·K) has an inside diameter of Di,1 = 150 mm and wall thickness ti = 20 mm while the outer steel pipe has an inside diameter of Di,1 = 250 mm and wall thickness . Determine the maximum allowable crude oil temperature to ensure the polyurethane foam insulation ( kp = 0.0425 W/m·K) provides an external convection heat transfer coefficient of ho = 500 W/m2·K. The convection coefficient associated with the flowing crude oil is hi = 450 W/m2·K. (2) It is proposed to enhance the performance of the pipe-in-pipe device by replacing a thin ( ta =10 mm) section of polyurethane located at the outside of the inner pipe with an aerogel insulation material ( ka = 0.012 W/m·K). Determine the maximum allowable crude oil temperature to ensure maximum polyurethane temperatures are below tp,max = 70°C. Determine the convection heat transfer resistance on the inside of the pipe per unit length, in m·K/W. Determine the conduction resistance of the polyurethane per unit length without the aerogel, in m·K/W. Determine the conduction resistance of the polyurethane per unit length when aerogel is used, in m·K/W. Determine the maximum crude oil temperature if no aerogel is used, in °C. Determine the maximum crude oil temperature if aerogel is used, in °C.
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