Cost analysis in RO desalination plants production lines: mathematical model and simulation

Abstract

In this article, the cost analysis of a m3 of desalinated water by reverse osmosis (RO) has been extensively studied. Although the capacities of production lines in these plants are normally different, a desalination plant is usually constituted by a set of production lines with identical capacities, which correspond to the total production capacity. Optimization cost of a more efficient production line affects the economy of scale. We report a mathematical model based on expressions related to costs based on production capacity. This study aims to present and analyze costs simulation for the production line in seawater desalination plants by RO technology. The work scope corresponds to production capacities of small desalination plants in the range between 500 and 15,000 m3/d in the Canary Islands. This range of options is the most widely deployed in this region. The methodology involves the collection and processing of statistical data, applied to research studies related to the thesis. Based on this, we plotted all the costs data in bar diagram and box and whisker diagrams. The outliers values study was carried out as well as the Kolmogorov–Smirnov and Shapiro–Wilk tests were carried out based on the Hubera’s M, Tukey’s biweight, Hampel’s M and Andrews’ wave estimators. Afterwards, the factorial analysis was carried out using the Barlett and Kaiser–Meyer–Olkin tests; the possible mathematical models were analyzed. This study provides an innovative aspect in costs analysis due to the fact that the study focused exclusively on the search for more technologically efficient production line with lower cost impact to the plant. The equation presented corresponds to the mathematical model based on the statistical data adjusted by 98% of the real cost for small desalination plants within the range mentioned. The existing deviations for each production range would be outlined from the analysis of the simulation regarding the mathematical equation of the calculated costs. To conclude, this article presents as a final result and conclusions, the mathematical model obtained, the corresponding real simulation graphic getting among other data, the existing deviation between the values obtained in this study and what is shown on the real data based on the seawater desalination costs, noting that it is less than 1.5%, both for the most efficient production line and for the remaining lines observed within the range previously established in the particular case of the Canary Islands.