Within the loop assessments, online monitoring technologies are identified which could be potentially integrated with the Utility Units DCS. It is recommended that the Safaniya staff address the cost/benefit of acquiring, implementing, and maintaining the identified technologies against more traditional methods such as process stream sampling and lab assay. Consideration should be given to the rapidity with which a damage mechanism can lead to failure and the proven efficacy of the monitoring technology.
In the discussion of on-line monitoring technologies, the Intertek team has indicated specific monitoring devices/systems that could be used for online monitoring of various parameters. The citation of these specific devices is to provide an example of a type of on-line monitoring technology only. The mention of a specific manufacturer or product should not be construed as an endorsement of that company or product by Intertek or the Intertek team.
DM LOOP – Seawater to MED Unit
Seawater from Arabian Gulf is screened at Drum Screen-Seawater intake G26-K-216, filtered and pumped to the MED unit. Before entering the MED unit, seawater is chlorinated and de- chlorinated. Seawater intake pumps G26-G-220A/B are included. Road crossing seawater line is underground.
Equipment & Main Piping
Process Chemistry: Seawater
Process Contaminants: Bacteria/Plankton, etc.
Mitigation & Control: Chlorinated/Dechlorinated. Underground line is cathodically protected
Max Operating Condition: 32oC, 520kPa (90oF, 75psi)
Primary Internal Damage Mechanisms
• General Corrosion
Specific Corrosion and IOW/Concern
If biocide dosing and chlorination are insufficient, MIC could occur. There are on-line monitoring systems such as the Emerson Model 499A free chlorine sensor could be used to monitor the Chlorination concentration to insure that the required dosing of 0.5 to 1 ppm is maintained. For Chlorine concentration measurement, equipment similar to could be employed. The primary means of preventing uniform corrosion are cathodic protection (Sacrificial Anode or Impressed Current-ICCP) and Anodic Protection.