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The concern about the proper use of mass and heat resources in the industry has led to adopt different alternatives for the operation and performance of the process systems. Schemes such as eco-industrial parks (EIPs) and sustainable cities have the purpose of enhancing the usage of the available resources through an exchange network where different resources are allocated among several industrial processes. Recently, the carbon–hydrogen–oxygen symbiosis networks (CHOSYNs) have been proposed as a special case of EIP, where the multiplant integration allows the exchange of carbon, hydrogen, and oxygen compounds among hydrocarbon processing plants. Previous CHOSYN designs have been focused on determining the most suitable allocation of resources to satisfy the material requirements for each industrial plant and obtain the best economic result for the total integrated system. Notwithstanding, this result usually provides unfair solutions, where the biggest industries have the main economic advantages, leaving aside the profitability of the smallest industries. This paper evaluates distinct allocation schemes in the synthesis of CHOSYNs through an optimization approach to identify fair solutions to allocate the available resources. A mathematical formulation is presented for three different justice schemes to design the material exchange network: social welfare, Rawlsian justice, and Nash schemes. The addressed case study has been previously analyzed through the optimization of the total annual profit, which allows comparing the utilities of all of the plants when the allocation schemes are included.

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Carbon−hydrogen−oxygen symbiotic networks (CHOSYNs) provide a systematic multiscale framework for integrating multiple hydrocarbon processing plants. Earlier approaches have focused on high-level performance benchmarking using atomic and stoichiometric targeting techniques, which are subsequently detailed to identify the implementation strategies for allocation and processing. These sequential approaches are very powerful for the cases involving benchmarks that are independent of the system details (e.g., minimum usage of raw materials, minimum discharge of wastes, maximum revenue). For objectives involving detailed process information (e.g., capital cost minimization), there is a need to include the system details early enough in optimization. This paper proposes a systematic approach for incorporating detailed process simulations throughout the various stages of synthesizing a CHOSYN. The proposed approach involves the use of computer-aided process simulators and simultaneous optimization for synthesizing a CHOSYN. Critical data are generated and used at each design stage. For existing facilities, targeting uses the simulated data on available resources and sinks (e.g., flow rate, composition, pressure, and temperature). Process synthesis is used to generate a set of candidate new units and plants to be added, while detailed simulation is used to size these plants and identify the specific needs for flows and compositions. The proposed approach is implemented for a case study that involves five existing plants and a set of seven candidate plants that can induce symbiosis. The results show final configurations with the selection of new plants, the reduction of raw material, the allocation of internal and external sources, and the details of process information, capital and operating costs, and flow rate, pressure, and temperature of the exchangeable streams across the network.