Hanwha Engineering & Construction (HENC) in Korea has selected Siemens to provide demineralization equipment and condensate polishing systems for the new Marafiq Yanbu power plant in Yanbu, Saudi Arabia.
The new plant will allow Marafiq to increase its power generation capacity to better serve industries based in the cities of Yanbu and Jubail. The multi-million dollar water treatment systems are scheduled for start-up in 2011.
The steam generator’s (boiler’s) turbines of the Marafiq power plant require water that is essentially free of Total Dissolved Solids (TDS) so they will not become corroded, scaled or fouled. Three Siemens mixed-bed demineralizer systems will polish desalinated water from the Red Sea to boiler feed water quality before being fed to the plant’s boilers. Demineralization with ion exchangers is an electro-chemical batch process for removing TDS from water.
When the steam from the boiler cools, condensate is formed, which can be collected and reused as boiler feed. Before reuse, the condensate must be purified or “polished” to remove impurities. Siemens’ condensate polishing systems, also referred to as deep-bed systems, use strong-acid and strong-base ion exchange resins to produce very high quality water. Four high-pressure spherical condensate polishers with the Fullsep external regeneration system will remove impurities such as metal oxides, trace ionic contaminants and silica from the condensate cycle to maximize water use and improve and maintain boiler chemistry. When the mixed-bed resin capacity is used up, the “spent” resin will be transferred to the three-vessel external system for separation, backwashing and regeneration. Deep-bed condensate polishers are typically used in applications where the feed water contains very low levels of TDS and where the power plant may have minor condenser leaks.
The equipment for the power plant in Yanbu will be designed, engineered and manufactured by Siemens in Singapore. HENC chose Siemens’ Fullsep external regeneration system because it offers minimum cross-contamination levels of the anion and cation resin, and thus ensures efficient resin regeneration for consistent water quality. The consistent performance of the condensate polisher system extends the life of the power plant and makes it more sustainable by reusing the return condensate.