SANILEC systems take full advantage of our knowledge and experience in the design of offshore skid mounted units, with strenuous area classification requirements. These systems generate sodium hypochlorite from seawater using an extensively field-proven electrochemical process for the disinfection of both water and wastewater.
The purpose of on-site generation of sodium hypochlorite solution from seawater is to economically and safely produce this powerful biocide and disinfecting agent in offshore applications. When injected into the cooling water circuits, on-site generated sodium hypochlorite solution provides efficient protection to the equipment against the growth of organic fouling (micro and macro). This occurs without the undesirable side effects of commercial hypochlorite (such as the build up of hard deposits by reaction of excess alkalinity with the substances dissolved in water) or the safety hazard connected with the transportation, storage and handling of chlorine gas. Because this technology eliminates dependency upon outside suppliers and the heavy costs of purchased commercial products, it finds application in a broad spectrum of offshore facilities requiring biofouling control of water systems. SANILEC for the on-site generation of hypochlorite from raw seawater have demonstrated reliable, economic and low maintenance operation in numerous installations throughout the world.
Process Description
Pressurized seawater is delivered to the SANILEC System where it is strained to 0.8mm to remove suspended solids. The seawater passes through a manual valve, a flow orifice (passive type) and a flow transmitter that provides local indication and low flow shut down. The seawater then passes through the electrolyzer cell and exits the cell as sodium hypochlorite solution and byproduct hydrogen gas. The solution then passes through a tank or cyclone to separate the hydrogen. The hydrogen is diluted with air using a blower to a safe level. The hypochlorite is then injected at a fixed flow rate with variable concentration to provide proper biofouling control to seawater systems.
SANILEC applications include:
Cooling Water In any marine application where seawater is used for cooling, biofouling must be considered. Buildup of marine growth in process equipment reduces efficiency, shortens the life and decreases the time between required maintenance. STDN provides a skid-mounted package that receives pressurized seawater and produces sodium hypochlorite at a concentration of 40 to 1660 ppm. Sodium hypochlorite can be injected at any point within the vessel to control marine growth. The product can be varied 0-100 percent to maintain the desired residual.
Fire Water Systems Offshore facilities that use seawater for their Firewater System must consider Biofouling. Mussels and algae can restrict the intake to firewater and jockey pumps. Restrictions in flow can compromise the performance of this vital safety equipment. STDN will supply a skid-mounted package that provides a shock dose of sodium hypochlorite at set intervals to the firewater pump caisson, and a continuous dose of sodium hypochlorite to the jockey pump cassion. The shock dose keeps the firewater pump caissons clean and free from macrofouling. The continuous dose maintains the Firewater Main Loop algae and slime free.
Water Flood In a typical water flood package sodium hypochlorite is used to restrict marine growth in the seachest, condenser, heat exchanger and downhole. Reduced marine growth in the condenser and heat exchanger can increase efficiency and significantly reduce the requirement for maintenance. Sodium Hypochlorite injected with the seawater in downhole applications can prevent slime and marine growth in the oil bearing substrate.
Ballast Water Treatment On-site generation of hypochlorite, a very proven technology for a new problem that is looking for a reliable, efficient and sensible solution in terms of economics, operations and the safety of personnel and the marine environment.
