4) A process furnace heats a fresh air near ambient temperature to a desired temperature of 300C. The process stream outlet temperature is regulated by manipulating the flow rate of fuel gas to the furnace, as shown below. TC Stack Furnace Hot Air Fuel Gas Fresh Air (a) Discuss the objectives of the control strategies. (b) What is the measured output? (c) What is the controlled variable? (d) What is the manipulated variable? (e) What are the possible disturbances? (f) Is this a continuous or batch process? (g) How many control loops are present in the figure? Classify them as a feedback or feed-forward controller? (h) Draw the control block schematic diagram and label all signals and blocks on the diagram