1. (a) You are working for a company which produces special fuel oils. Your manager asks you to study the Piping and Instrumentation Diagram (P&ID) of a distillation column (APPENDIX Q1). Answer the following questions according to the diagram. (i) Determine how the inventory parameters are controlled in the process, including the identification of the controlled variables and the manipulated variables. (6 marks) (ii) Determine whether the distillation column is controlled by an energy balance or a mass balance control scheme. Explain in which situation the mass balance scheme is preferred. (5 marks) (iii) Explain how the compositions at the top and bottom products are controlled. (8 marks) (b) Explain the following terms used in plantwide control: (i) Differences between upstream and downstream methods. (4 marks) (ii) Snowball effect in recycle systems. (2 marks) . Inventor control 100 PS 3