Figure 2 Process flow diagram of CDU I, Kaduna Refining and Petrochemical Company Ltd
The process data and the PFD were used to carry out simulation of the CDU plant in Aspen hysys. Using the process simulation data of CDU I, the supply temperature (Ts), target temperature (Tt), flow-rate and heat capacity of each stream in the heat exchangers network were extracted for carrying out the pinch analysis. Also the areas of each heat exchanger in the network were extracted. The physical properties of the products from the crude distillation unit are shown in Table 1. Aspen Hysys Process Simulator was used for the process simulation of the plant streams. The source and target temperatures of all the streams, mass flow rates, feed and product compositions of the feed and product of the plant were used for obtaining the specific heat capacities and enthalpies of the streams.
Table 1 Data extracted from Aspen Hysys simulation, showing the heating and cooling of the process streams