NAMS 2002 Workshop - ICOM 2008

Desalination I – 6
Monday July 14, 5:00 PM-5:30 PM, O’ahu
Performance Testing of a Large Seawater RO Desalination Plant
A. Khawaji (Speaker), Royal Commission for Jubail & Yanbu, Yanbu Al-Sinaiyah, Saudi Arabia
J. Wie, Saudi Arabian Parsons Limited, Yanbu Al-Sinaiyah, Saudi Arabia,
JongMihn.Wie@parsons.com
Yanbu Industrial City in Saudi Arabia depends upon seawater desalination for its
entire fresh water supply. The fresh water is supplied by a desalination complex
that consists of a multi- stage flash distillation plant with a capacity of 95,760
m 3 /day and a reverse osmosis (RO) plant with a capacity of 50,400 m 3 /day. The
RO plant was constructed recently by the Royal Commission for Jubail & Yanbu.
This seawater RO plant is made up of six 8,400 m 3 /day permeate trains. The
plant consists of five basic components: seawater supply, feedwater
pretreatment, high pressure pumping, RO membranes, and permeate posttreatment.
The RO plant is designed to desalt the seawater with total dissolved
solids (TDS) of 46,400 ppm at 22 °C seawater temperature. RO feedwater is
treated with various chemicals such as sulfuric acid, ferric chloride, sodium
bisulfite, and sodium hypochlorite. Filtration is carried out in two stages with dual
media filters and cartridge filters. The multistage high pressure centrifugal pumps
are operated at 64 to 76 kg/cm 2 g. The high pressure pumps are coupled to
energy recovery turbines for energy recovery from the concentrated brine stream
to reduce electrical pumping costs. The RO membranes are made of cellulose
triacetate using the hollow fine fiber configuration. The plant is installed with
1,824 RO membrane elements. Salt rejection by the membranes is
approximately 99.4%. The plant produces permeate with a maximum TDS of 500
ppm at a minimum recovery ratio of 35% for the single pass permeators. The
plant is equipped with a distributed control system using state-of-the-art
computerized technology. This paper presents the major plant design features
and the results of the testing conducted to determine whether the plant
performance guarantee described in the contract technical specifications can be
met. The performance testing includes normalized permeate flow rates,
permeate water quality, recovery rates, chemicals consumption, power
consumption, silt density index values and residual chlorine concentrations of
seawater and filtered water, permeate pHs, and bacteriological tests of product
water.