Question: steam is widely used in food processing industries for noncontact...
Steam is widely used in food processing industries for non-contact heating (e.g.
DelGrosso’s has kettles where ~6700 lb. of tomato sauce or salsa are heated through a steam jacket). Steam is conveyed to unit operations, like kettles, in pipes and heat loss is a major concern. For example, there is a stainless steel (AISI 316) steam pipe with an inside diameter of 8 cm and a wall thickness of 5 mm. The inside surface temperature of the pipe is maintained at 150oC by the steam. The pipe is wrapped in a layer of mineral wool insulation (2 cm thick) and then a layer of medium density polyurethane foam (1 cm thick). The outside temperature of the foam insulation is 20oC. Calculate the rate of heat loss per meter length of pipe. (50 W for length = 1 m) What heat transfer resistances are negligible in your analysis?