Optimized Heat Exchanger Design for Waste Heat Recovery in Offshore Gas Turbine Heating Systems: Case Study of NEPL Facility, Port Harcourt

Abstract: This study presents the successful design and simulation of a waste heat recovery system (WHRS) tailored for reactivating the heating medium in an offshore gas turbine at the Nigerian National Petroleum Company Exploration and Production Limited (NNPC E&P Ltd) Production Facility. The research is driven by the ongoing pursuit of enhanced energy efficiency and sustainability in offshore operations. A standard modeling approach was employed, utilizing process flow diagrams (PFDs) for system integration and Computational Fluid Dynamics (CFD) analysis, coupled with Aspen HYSYS simulations to assess system performance under operating conditions. Flue gas composition analysis was conducted to determine input parameters for the WHRS design. Optimization techniques were implemented to establish the optimal heat exchanger design configuration. The heat exchanger was designed as a shell-and-tube system with 130 tubes of 20 m length and 0.025 m outer diameter. Simulations were conducted to evaluate the heat exchanger performance, determining a heat duty of 648,985 W, an overall heat transfer coefficient of 112.66 W/m²K, and a corrected Log Mean Temperature Difference (LMTD) of 281°C. Aspen HYSYS simulations validated system performance, yielding a tube-side outlet temperature of 130°C and a shell-side outlet temperature of 335.5°C. The results indicate improved energy recovery throughout the simulated process, confirming the feasibility of implementing waste heat recovery in crude oil preheating operations, contributing to improved energy management in offshore production facilities.

Keywords: Waste Heat Recovery (WHR), Simulation, Aspen HYSYS, Heat Exchanger Design, Offshore Gas Turbine, Shell-and-Tube Heat Exchanger, Computational Fluid Dynamics (CFD), Energy Recovery .