(373m) A Multi-Stakeholder Optimization for Total Energy Integrated Systems

Nowadays, the increment for the energy consumption represents a key challenge in order to achieve a higher economic and social development around the world owing to the difficulties to satisfy the significant energy demands in addition to the environmental impact associated to the production and consumption of energy. In this regard, the processes industry is a sector with large energy demands; for this reason, it is important to design new strategies aiming to reduce its energy consumption. This topic has been widely studied through the optimization of Heat Exchanger Networks (HEN), which is able to generate economic and environmental benefits. However, the chemical processes require external utilities for their appropriate operation such as electricity as well as hot, cold and refrigeration, which must be produced in auxiliary units. In the production of these utilities, there is residual energy, which usually is wasted without the possibility to take advantage of this energy. Although, the energy integration among all the previous plants provides a higher level of benefits (owing the residual energy can be reused), there are several concerns that could restrict or prevent its adequate implementation. Hence, this work proposes the energy integration for a trigeneration system in an Eco-Industrial Park (EIP) composed by a HEN, a conventional Rankine cycle, an organic Rankine cycle (ORC) and absorption refrigeration (AR) system considering the individual policies and satisfaction with the purpose to visualize the best configuration (where all the members are benefited) in order to encourage the participation in interaction schemes.

Moreover, the proposed design is represented by a superstructure accounting for all the possible energy interactions among each plant with the purpose to maximize the energy reuse. In this context, the primary energy (solar energy, biofuels and fossil fuels) is only supplied to the conventional Rankine cycle, which provides the heating needed for the operation of the AR, ORC and the heat exchanger network.

The mathematical approach includes overall and individual objective functions: the overall targets are the maximization of the total annual profit (TAP), simultaneously with the minimization of the greenhouse gas emissions (GHGE) and maximizing the number of jobs generated by the project (NJOBS). Whereas the individual goals consist in maximizing the total profit for each plant as well as the individual return on economic and environmental investments. Additionally, the economic analysis is carried out through the multi-stake holder technique to determine the best and worst scenarios for each plant that integrates the EIP. Thus, the methodology has been addressed to identify the utopic (the solution that involves the best economic solution for each member) and nadir points (where the worst economic result for each plant is obtained).

Finally, an example is implemented to illustrate the tradeoffs of the proposed methodology. It worth to mention that this methodology represents a useful tool to incite the participation in cooperation schemes like EIP’s.