12. Methane is to be pumped from one vessel through a pipe of length 480 m to a second vessel, which is at a pressure of 25 atm absolute. The required flow rate is 0.3 kg/s and the allowable pressure at the pipe inlet is 32 atm absolute. If flow conditions are isothermal and the gas temperature is 30C, what diameter of the pipe is required? What is the heat transfer rate