More efficient production line with Desalination plants using reverse osmosis

Abstract

We introduce the present article with the intention to define the most efficient production line for reverse osmosis seawater desalination plants. We show the relationship between the cost of desalinated water per cubic meter according to the production capacity, verifying a scale economy as the production rises significantly. The destination of this article is within the reach of small desalination plants in the range between 500 and 15,000 m³/day in the Canary Islands Autonomous Community. Specified range is the most established in the Autonomous Community. Approximately, more than about the 90% of the desalination plants have a production capacity corresponding to the selected range. The methodology used consists of calculating each one of the costs involved in the seawater desalination process, applying actual prices, and obtaining a graphic serial according to prices tolerance, from −5% to a value of +5%. Concerning staff costs, we have recovered data from the iron and steel industrial sector collective agreement of the Autonomous Community. In our article, we present all the elements that directly affect each one of the costs, equations, and formula based on factors affecting each one of them, with actual market prices in the Autonomous Community of Canary Islands, making all calculations and obtaining a family of costs graphics for each one. As an innovative and original article, we present the real costs for small desalination plants, in between the said range. We also present a new cost, to bear in mind, according to current regulations, which is the environmental cost, based, among other things, in solving the problem of brine spills directly into the sea. Cost has been calculated based on the introduction of a new machinery and canalization to reduce the before mentioned environmental impact. Lastly, this article, as a final result, presents the total value of the cost in €/m³ with the results and graphics for each plant between the before established range in the Canary Islands, obtaining according to them, the most efficient production line. We present the results based on a small fluctuating scale economy. Our article presents costs results in order to be able to select the most convenient production line in each case, based on the production capacity and on the several own factors of each individual cost. The aim of our work is to study the influence of the fouling factor and temperature according to the desired production (500–15,000 m³/day) on the cost in €/m³. Based on it, we study the operational and functional costs searching for the production line with the best efficiency.

Keywords:

• Reverse osmosis
• Unit costs
• Canary Islands
• Desalination
• Operating parameters

Notes

Presented at the International Conference on Desalination for the Environment, Clean Water and Energy, European Desalination Society, April 23–26, 2012, Barcelona, Spain