[30 marks overall] Ethylene (C2H4) flows through a pipeline 10km long to a receiving station A. At a point 3km from A, a spur (branch) leads off the main pipeline and runs 5km to receiving station B. The internal diameter of the main pipeline is 0.2m and that of the spur is 0.15m. The flow rates into A and B are regulated by valves at these locations. If the pressure immediately upstream of valve A is 3.88 bar (absolute) and that at B is 3.69 bar (absolute) when the flow rate into B is 0.63kgs1, calculate the following assuming isothermal compressible flow at 20C, and a Fanning friction factor of f=0.0045 : (a) [10 marks] The pressure (bar) at the junction between the main pipeline and the spur. (b) [8 marks] The mass flow rate (kgs1) of ethylene from the spur into A. (c) [2marks] The total mass flow rate in the main pipeline (kgs1); and (d) [10 marks] The pressure (bar) at the beginning of the main pipeline