SIMPLIFIED SUPERSTRUCTURE APPROACH FOR DESIGNING HEAT EXCHANGER NETWORK IN HEATING SYSTEMS OF DISTILLATION CRUDE OIL UNIT: ZAWIYA REFINERY PLANT CASE STUDY

Abstract

This study presents an analysis of the heat exchanger network design for the crude oil refinery's distillation unit at the Zawia plant. Optimization software was utilized to determine an optimal minimum temperature difference (ΔT_min) of approximately 20°C. The HINT software also calculated the minimum hot utility (Qh_min = 23,457.156 kW) and cold utility (Qc_min = 10,882.814 kW) requirements for the fractional distillation unit. The analysis indicated that a total of 29 shells are necessary based on the thermal requirements of the hot streams. A systematic superstructure approach was employed to segment the composite curves into eight distinct intervals. A graphical technique provided a theoretical minimum that effectively informed the design optimization process. Additionally, grid diagram simulations were conducted to refine the configuration by incorporating practical constraints. To enhance the efficiency of the superstructure, the integration of single-shell and multi-shell heat exchangers is proposed, resulting in a reduction of total units to 18. This study underscores the efficacy of the proposed methodology as a robust tool for achieving optimal heat integration solutions, thereby maximizing energy savings and minimizing costs in refinery operations.