Process integration techniques have been well established in various areas, which include energy recovery, in-plant material recovery, industrial symbiosis, energy planning, financial management, etc. Such techniques are widely applied in the research community and industrial applications. Synthesising and designing an eco-industrial park via process integration techniques is recognised as one of the most effective strategies to promote sustainable industrial systems. Feasible operating range analysis has been introduced to evaluate and determine the true operating potential of an eco-industrial park coalition without experiencing design and performance limitations. Such tool also acts as a comprehensive decision-making tool for designers to evaluate the performance of an integrated process at different operational states. In this perspective, a novel mixed-integer linear programming model is presented in this work for simultaneous design and integration of multiple processes to form an eco-industrial park. The true potential and performance of the eco-industrial park developed can be assessed at different operational states. To illustrate the proposed approach, an industrial case study on design of eco-industrial park in oil palm industry, which consists of palm oil mill, integrated biogas and wastewater treatment system, palm-based biorefinery, and combined heat and power system, is solved and presented. [Display omitted] • A systematic approach to design and integrate multiple processes simultaneously. • Improves resource efficiency and reduce carbon footprint. • Determine the true potential and performance at different operational states. • A palm-based eco-industrial park case study was presented. [ABSTRACT FROM AUTHOR]