Answer Happy

Flow has stopped in a subsea pipeline which is 10.0 km in length, has an inner diameter of 8.00 in and a wall thickness of 1.50in. The initial temperature for use in the lumped capacitance model is 90.0∘C and the surroundings are at a constant temperature of 6.0∘C. The density and specific heat capacity of the pipeline fluid are 825 kg m−3 and 3.65 kJ kg−1 K−1 respectively. The overall heat transfer coefficient is 5.00 W m−2 K−1 (based on the outer surface area of the pipeline). Your team is concerned about the possibility of hydrate formation when the fluid temperature reaches 20.0∘C. How many hours do you have before hydrate formation may occur?