Date of Award

5-2002

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Environmental Science

First Advisor

Gharib S. Aly

Second Advisor

Dr. Mohamed Abdul-Karim

Third Advisor

Dr. Sergie Aghachev

Abstract

Some data was collected and reported for seawater desalination in the gulf region. Some information is also given regarding the multi–stage flash (MSF) desalination plants in the United Arab Emirates. The total installed capacity of these plants is 518 MIG. It was revealed that the water demand in the Abu Dhabi Emirate alone has increased by 30 folds during the last 25 years.

A literature survey was conducted mainly on modeling and simulation of MSF desalination processes. A number of commercial software such as Speedup, Camel, and EvapoLund were reviewed with special emphasis on EvapoLund that has been used as the process simulation tool in the thesis.

Brief descriptions are given for different multi-stage flash desalination processes including single-stage MSF, once – through MSF, brine - mix MSF, and conventional brine - recycle MSF.

Two MSF desalination plants at the Al-Taweelah dual-purpose power and desalination complex in Abu Dhabi were selected for study. Both are similar to each other, but designed, built and installed by different companies. The main objective was to check some of the design data provided by the contractor and to evaluate the plant performance at fouled operating conditions.

A brief mathematical background is given including mass and energy balances, and rate equations for the conventional brine - recycle MSF process. The simulation results obtained, using the commercial software EvapoLund, revealed some discrepancies for one of the plants is chosen as case study and rather good resemblance for the other plant. It was also established that acid wash for one of the plants was needed to restore the value of its overall heat transfer coefficients to the design values. The U-values for the other plant were computed using design data at clean and fouled conditions.

Using some data available from the contractor, an economic evaluation was made to establish the real unit production cost. The annual capital cost, annual operating cost, and the water unit cost were calculated as 0.39, 1.16, and 1.55 $/m3, respectively. The last figure is equivalent to 5.72 Dhs/m3.

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