Optimising the Sustainability Performance of an Industrial Park: an Energy-Water-Food Nexus

Rapid population growth has led to an increase in the demand for energy, water and food resources utilisation which results in environmental impacts and contributes to resource depletion. Therefore, it is necessary to design networks using various tools such as process integration and optimisation approaches, which have been applied to Energy-Water-Food (EWF) nexus studies. The main objective of the study is to design a systematic approach to capture the trade-offs between the economic and environmental metrics of sustainable design with industrial parks. It presents a novel superstructure and mathematical optimisation model that captures the synergies within EWF nexus considering interplants. Moreover, novel to this study, is the exergetic approach, which has not been previously applied to EWF nexus studies within industrial parks. The proposed nexus superstructure is applied to an eco-industrial park including wastewater treatment units, desalination plant, agricultural sub-systems, and a biomass gasification process for the recycling of biomass waste. The case study includes water-energy sources and sinks for chemical plants such as ammonia/urea and GTL processes in the State of Qatar which are simulated using the “what'sBest” Mixed-Integer Global Solver for Microsoft Excel by LINDO Systems Inc. Different cases with multiple optimisation objectives are evaluated in order to capture the trade-offs between the economic and environmental emission. Different indicators are used to assess the system resource efficiency such as exergy efficiency and global warming potential (GWP). The main focus is on capturing the synergic potential from utilising biomass from within the food sector and producing the syngas which decreases the natural gas consumption in other systems. Results of the study demonstrate clear benefits of water integration and biomass utilisation and contribute to the reduction of resource consumption. In the best scenario, the system demonstrates an 18 % reduction in the global warming potential, while the total annual cost of the design is increased by almost 9 %. The exergy efficiency of the system is enhanced reaching 53 %.