Methane is liquefied in a Claude liquefaction system as shown below. Gaseous Methane is compressed to 80 bar and precooled to 300K (stream 4). This high-pressure methane gas is further cooled in heat exchanger I to a temperature of 260K (steam 5) and then split into two streams, a draw-off stream of 15% to the expander (stream 11) with the main stream (the remaining 85% ) flowing to the throttle valve via heat exchanger II (streams 6 to 7). The expander and throttle valve exhaust to a pressure of 1 bar (streams 12 and 8). The temperature of the methane gas leaving the expander (stream 12) is 150 K. Recycle methane gas (stream 15) leaves the exchanger system at 1 bar and 280K. Determine the following: i) The specific enthalpy (kJ/kg) of streams 4,11,12 and 15 ii) If 100kg/h of liquid methane (stream 9) is produced, the required mass flow rate (kg/h) of methane in streams 4,8,10,11 and 15 . iii) The temperature (C) and specific enthalpy of streams 7,8,13 and 14. iv) The power (kW) generated by the expander and the efficiency of the expander Note: You may assume that there is no pressure drop across the heat exchangers or the separator for this process. Properties of saturated methane at 1 bar: - Temperature =111K - Specific enthalpy of liquid, Hf=285.4kJkg1 - Specific enthalpy of vapour, Hg=796.9kJkg1 - Specific entropy of liquid, Sf=4.928kJkg1K1 - Specific entropy of vapour, Sg=9.521kJkg1K1 Properties of superheated methane are provided