ABSTRACT
The former was preferred as it provides a significantly higher heat transfer coefficient, easier separation of non-condensable gases, and easier cleaning of coolant scale. The tube-side velocity is an important variable to iterate as it directly affects the heat transfer coefficient, the pressure drop and the coolant flow rate. The tube-side velocity effectively determines the coolant flow rate and is one of the controlling factors determining the heat transfer area. The shell-side pressure drop across the after-cooler was calculated to be 1.05 kPa, which is typical of many condensers and is considered to be conservative. The insulation material must be selected for the maximum operating temperature of the vessel and based on the thermal conductivity of the insulation. A desuperheater–cooler–condenser, which functions as the after-cooler in the phthalic anhydride process for phthalic anhydride production, was designed to recover approximately 50% of the PAN vapour which is present in the reaction gases.
