(364g) Profit Distribution in Interplant Heat Integration Using a Hybrid Optimization Approach | AIChE

(364g) Profit Distribution in Interplant Heat Integration Using a Hybrid Optimization Approach

Authors 

Lira-Barragán, L. F. - Presenter, Universidad Michoacana de San Nicolás de Hidalgo
Hernández-Pérez, L. G., Universidad Michoacana de San Nicolás de Hidalgo
Rubio-Castro, E., Universidad Autónoma de Sinaloa
Ponce-Ortega, J., Universidad Michoacana de San Nicolas de Hidalgo
Energy integration allows recovering excess heat generated by industrial plants. Energy integration is especially important for the reduction of wasted energy, where the benefits can be from the economic and environmental points of view. Heat exchange networks (HEN) help to reduce the utility demands of industrial plants by integrating process streams. In addition, a set of techniques have been developed to allow the simultaneous heat integration of HEN and thermal engines. While for further energy integration, interplant heat integration has been considered.

However, the main objective of most of these studies is to maximize heat recovery while maximizing the overall economic benefit, without considering the distribution of costs and benefits among different stakeholders. In addition, each involved industrial plant needs different resources of utilities, refrigeration, and electricity. Therefore, if a fair distribution of costs and benefits among different stakeholders is not obtained, the resultant heat exchange network may be unacceptable for the affected stakeholders. Hitherto, cost/benefit distribution in interplant heat integration has only been approached through game theory, where resource distribution is considered a game between stakeholders. Likewise, this approach is sequential, where first, the total annual costs are minimized and then the cost distribution among different stakeholders is performed. Furthermore, the papers that have used game theory do not consider the interplant heat integration with thermal engines.

On the other hand, different schemes for the distribution of resources among various stakeholders (Social Welfare, Rawlsian Welfare, and Nash scheme) have also been reported. These schemes have been implemented in various multi-stakeholder systems, in electricity markets, in the coal-fired power market, and water distribution networks. Furthermore, to find the best solution among stakeholders, an approach was proposed to compare the multiple allocations obtained under the Social Welfare, Rawlsian Welfare, and Nash scheme. Moreover, it has been correctly used for fair allocation in the optimal design of integrated residential complexes, in the synthesis of carbon-hydrogen-oxygen symbiosis networks, distribution of COVID-19 vaccines using an optimization-based strategy, as well as in water scarcity at the macroscopic level. Also, this approach is simultaneous for profit maximization and profit allocation.

Therefore, this work presents an optimization approach for fair cost/profit allocation among the involved industrial plants in interplant heat integration considering three different thermal engines. The incorporation of the allocation schemes (Social Welfare, Rawlsian Welfare, and Nash) is used to provide fair solutions for stakeholders. Moreover, the proposed mathematical model can determine the individual costs/benefits of the involved industrial plants so that distinct industrial plants with different requirements for utilities, cooling, and electricity can be considered. Furthermore, previous heat integration studies implementing thermal engines use significant assumptions through fixed efficiency factors as well as internal variables (operating temperatures, flow rates, cost data, thermodynamic properties, etc.), because optimizing thermal engines based on deterministic approaches is exceedingly difficult due to the use of thermodynamic, thermohydraulic and transport models. For these reasons, this paper presents a solution procedure that consists of a hybrid metaheuristic-deterministic optimization strategy, where thermal engines are properly simulated and optimized through the MS Excel – VBA - Aspen Plus link (using thermodynamic and thermohydraulic models), so the results obtained under the different allocation schemes are accurate. A case study with four different scenarios is shown to evaluate the proposed approach. The results show different solutions for thermal engines, as well as different revenue distributions under the allocation schemes. Optimal operating conditions are found for thermal engines. Also, it is shown that for this case study the Rawlsian scheme provides a fair allocation of revenue and costs.