Economic, Energy, Exergo-Economic, and Environmental Analyses and Multiobjective Optimization of Seawater Reverse Osmosis Desalination Systems with Boron Removal

Abstract

We presented economic, energy, exergo-economic, and environmental analyses and multiobjective optimization (MOO) of seawater reverse osmosis (RO) desalination systems with boron restrictions. Exergo-economic unit cost for flows and exergy destruction for components were included. Life cycle assessment (LCA) principles with the contributions of construction and operating were introduced. An improved augmented ε-constraint method was adopted for solving the MOO problems. Unnecessary iterations were avoided by bypass parameter. Results showed that the Pareto-solution with a weighting of 0.4 could provide good performances for all objective functions. The CO 2 emissions reduction of 9.0% could be achieved, while the water cost is increased by 3.3%. Fixed cost dominates EUC. The environmental impact of construction is neglectable, while electricity consumption accounts for the largest share of CO 2 emissions from 93.4% to 97.8%. The details of energy utilization for components, the irreversibility, and equipment cost assigned to the streams are analyzed by using exergy and exergo-economic analyses. The overall emergy-based exergo-environmental performances of the systems are range between 81.5% and 84.6%. Both the component and exergy destruction related ecological emergy rates need to be improved.

Climate Change Mitigation Strategy through Membranes Replacement and Determination Methodology of Carbon Footprint in Reverse Osmosis RO Desalination Plants for Islands and Isolated Territories

“…Of special mention is the use of tools or pilot systems in plants. All of this must comply with the parameters for the quality of the water at the end of the process, which must have values below the maximums permitted by the National and European regulations on water for human consumption, as well as the recommendations of the World Health Organization (WHO) [13][14][15].…”

“…The depth of the seawater intake also represents a parameter or variable for the energy and economic evaluation of the system, since the deeper the intake, the more stable the temperature range of the supply water [14,15]. This means that the temperature of the intake does not rise so much in summer and low energy consumption membranes can be introduced, complying with the water quality required in the permeate, which previously, at higher temperatures, we only achieved with high rejection membranes and greater energy consumption.…”

“…The magnitude of these emissions depends on the set of technologies that make up the energy generation system of the electrical network to which the water production plant is connected. The energy produced by this set is often referred to as the energy mix, which tends to depend largely on the territory and energy policy [13][14][15][16][17][18][19].…”

Optimization of Energy Efficiency, Operation Costs, Carbon Footprint and Ecological Footprint with Reverse Osmosis Membranes in Seawater Desalination Plants

“…Similarly, to calculate the ecological footprint, we follow previous methodology [11][12][13][14], which is expressed in Table 2.…”

“…In the same way, we analyze data from the different seawater desalination plants we visited, obtaining data on thousands of hours of operation in many cases. We have developed techniques to improve the energy efficiency of seawater desalination membranes in Membranes 2021, 11, 781 2 of 18 strict compliance with the water quality parameters established by national and international regulations, or even by organizations such as the World Health Organization [11][12][13][14][15][16][17][18][19].…”