A pipe 30 m long with an outer diameter of 75 mm is used to convey steam at a rate of 1000 kg / hour. The vapor pressure is 198.53 kPa entering the pipe with a quality of 98%. The pipe needs to be insulated with a thermal conductivity of 0.2 W / (m K) so that the quality of the steam will only slightly decrease to 95%. The outer surface temperature of the insulation is assumed to be 25 ° C. Ignore resistance conductive of the pipe material and it is assumed that there is no pressure drop in the pipe. a. Determine the enthalpy of incoming vapor = Answer kJ / kg. b. Determine the enthalpy of steam coming out = Answer kJ / kg. c. Determine the vapor heat change / loss along the flow = Answer watt.

A pipe 30 m long with an outer diameter of 75 mm is used to convey steam at a rate of 1000 kg / hour. The vapor pressure is 198.53 kPa entering the pipe with a quality of 98%. The pipe needs to be insulated with a thermal conductivity of 0.2 W / (m K) so that the quality of the steam will only slightly decrease to 95%. The outer surface temperature of the insulation is assumed to be 25 ° C. Ignore resistance conductive of the pipe material and it is assumed that there is no pressure drop in the pipe. a. Determine the enthalpy of incoming vapor = Answer kJ / kg. b. Determine the enthalpy of steam coming out = Answer kJ / kg. c. Determine the vapor heat change / loss along the flow = Answer watt.