Luis Fernando Lira-Barragán

Synthesis of water networks considering the sustainability of the surrounding watershed

Abstract This paper presents a new mathematical programming model for the optimal synthesis of recycle and reuse networks considering simultaneously the integration of the water network system and the surrounding watershed to satisfy process and environmental constraints. The model considers the optimal location of the new industrial facility to integrate its wastewater discharge to the environment with the surrounding watershed through a disjunctive formulation. The pollutants discharged for the new plant are tracked simultaneously with the other discharges to the watershed (i.e., residential, sanitary, industrial and extractions), and the natural phenomena that affect the composition of the watershed (i.e., evaporation, filtration, etc.), in addition to the chemical reactions that are carried out in the rivers. The objective function consists in minimizing the total annual cost that is constituted by the installation of the new plant cost (including the transportation for raw materials, products and services, as well as the land cost), the wastewater treatment costs (including the piping cost) and the fresh sources cost. Two example problems were used to show the applicability of the proposed methodology.

An MFA optimization approach for pollution trading considering the sustainability of the surrounded watersheds

Abstract This paper proposes a mathematical programming model for the pollution trading among different pollution sources which considers the sustainability of the surrounding watershed. The formulation involves the minimization of the costs associated to the implementation of the required technology to satisfy the environmental constraints in order to achieve optimal water quality conditions. The model uses a material flow analysis technique to represent changes on the behavior of the watershed due to the polluted discharges. The material flow analysis considers all discharges and extractions (i.e., industrial and residential discharges, pluvial precipitation, evaporation, etc.) as well as the chemical and biochemical reactions taking place in the watershed. In the context of pollution trading, the implementation of the proposed formulation determines if an industrial source must buy credits to compensate the violation of environmental constraints, or if it requires the installation of treatment technologies to sell credits to another source. The formulation was applied to a case study involving the drainage system of the Bahr El-Baqar region in Egypt; the results show the advantages of the proposed approach in terms of cost and sustainability.

Optimal Reuse of Flowback Wastewater in Shale Gas Fracking Operations Considering Economic and Safety Aspects

Abstract This work presents a mathematical programing formulation for the optimal management of flowback water in shale gas wells considering economic and safety aspects. The proposed formulation accounts for the time-based generation of the flowback water, as well as the options for treatment, storage, reuse, and disposal. The economic objective function is aimed at determining the minimum cost for the fresh water, treatment, storage, disposals and transportation. The safety objective accounts for the risk associated to a failure in the treatment units and its consequence in human deaths. In this regard, the proposed method is able to consider different treatment units with different operating efficiency factors, costs and risks. To carry out the water integration, a recycle and reuse network is proposed. A given scheduling for the completion phases of the wells is required to implement the proposed method. Finally, an example problem is presented to show the applicability of the proposed method.

Optimal design of water networks for shale gas hydraulic fracturing including economic and environmental criteria

This work proposes an optimization approach for designing efficient water networks for the shale gas production through the recycle and reuse of wastewater streams reducing the freshwater consumption and effluents considering economic and environmental goals. The economic objective function aims to minimize the total annual cost for the water network including the costs associated with storage, treatment and disposal (capital cost) as well as freshwater cost, treatment cost and transportation costs. The environmental objective is addressed to deal with the minimization of the environmental impact associated with the discharged concentration of total dissolved solids in the wastewater streams and the freshwater consumption through an environmental function that represents the benefit for removing pollutants using the eco-indicator 99 methodology. The methodology requires a given scheduling for the completion phases of the target wells to be properly implemented by the available hydraulic fracturing crews during a time horizon. The model formulation is configured to determine the optimal sizes for the equipment involved by the project, particularly the sizes for storage and treatment units are quantified by the optimization process. A case study is solved to evaluate the effectiveness of the proposed optimization approach.Graphical abstract

Chapter 17 – Dynamic Optimization for the Optimal Location of New Industrial Facilities Considering the Sustainability of the Watershed

Abstract This chapter presents a new dynamic approach for the optimal synthesis of water treatment networks considering environmental and sustainability constraints simultaneously. The proposed model considers the optimal location of new industrial facilities to integrate dynamically their wastewater discharges to the environment through a disjunctive formulation. The discharged pollutants from the new plants are tracked simultaneously with other discharges to the watershed (i.e., residential, sanitary, industrial, and extractions) and the natural phenomena that affect the composition of the watershed (i.e., evaporation, filtration, etc.) in addition to the chemical reactions that are carried out in the rivers. The mixed-integer dynamic optimization formulation allows identifying the time periods where the watershed conditions are critical in terms of sustainability. The objective function consists in minimizing the total annual cost that is composed by the installation cost and the wastewater treatment costs. An example problem is used to show the applicability of the proposed methodology.

Sustainable Integration of Heat Exchanger Networks and Utility Systems

Abstract This work deals with the problem of synthesizing sustainable trigeneration systems (i.e. heating, cooling and power generation cycles) integrated with heat exchanger networks accounting simultaneously for economic, environmental and social issues. The trigeneration system is comprised of steam and organic Rankine cycles and an absorption refrigeration cycle. Multiple sustainable energy sources such as solar energy, biofuels and fossil fuels are considered to drive the steam Rankine cycle. The model is aimed to select the optimal working fluid to operate the organic Rankine cycle and to determine the optimal system to drive the absorption refrigeration cycle. The residual energy available in the steam Rankine cycle and/or the process excess heat can be employed to run both the organic Rankine cycle and the absorption refrigeration cycle to produce electricity and refrigeration below the ambient temperature, respectively.

Synthesis of Sustainable Property-Based Water Networks

Abstract This work presents a new mathematical programming model for the optimal integration of an industrial water network and its supporting watershed. In particular, the model determines the optimal location of a new industrial facility considering the sustainable integration of its wastewater discharges with the surrounding watershed through a disjunctive formulation. The behavior of the watershed impacted by the new discharges is described by the material flow analysis (MFA) technique in terms of property balances. The MFA technique considers all inlet and outlet streams in the watershed (i.e., residential, sanitary, industrial discharges and extractions). Therefore, for a new industrial plant, the proposed model allows to track the water properties throughout the watershed and determine the allowable level of discharges. The objective function involves the minimization of the total annualized cost that includes the costs for the installation of the new plant (including the transportation for raw materials, products and services, as well as the land cost), wastewater treatment, piping, and the purchase of the fresh sources. The resulting model is a mixed-integer nonlinear program (MINLP) and a case study for one of the most important watersheds of Mexico is presented to demonstrate the advantages of the proposed formulation. The results show that the environmental regulations are not enough to satisfy the sustainability of the integrated system (i.e. new industrial plant, watershed and other elements of the environment). Hence, unlike previous approaches, the proposed model yields sustainable water networks by taking into consideration simultaneously in-plant water integration and its interaction with the surrounding watershed including various environmental elements such as neighboring plants, cities and agricultural areas.