METROL SEA-CELL Electrochlorinator | SLB



METROL SEA-CELL Electrochlorinator

Prevent organism growth in your seawater systems with sodium hypochlorate

Streamlined, environmentally friendly, and efficient, the METROL SEA-CELL electrochlorinator uses electricity and the naturally occurring chloride ions in seawater to generate sodium hypochlorite for effective control of biofoulants. Organisms large and small can accumulate on equipment and in pipelines, reducing performance and potentially damaging system components to the point of complete shut down or failure. Anywhere seawater is used as an input for a process, an electrochlorinator should be used for biofoulant protection.

This electrochlorinator can provide increased run-times and protection of other seawater treatment equipment in a wide range of applications. Onshore uses include industrial and refinery cooling water, while offshore implementations range from oil and gas platforms and ships to floating production, storage, and offloading (FPSO) facilities.

METROL SEA-CELL Electrochlorinator
Standard SEA-CELL electrochlorinator

Flexible, modular design and controls

The SEA-CELL electrochlorinator is available in several standard models, providing scalability with fewer cells. It can be incorporated into automated chlorinator packages complete with detailed instrumentation and control features, which provide online availability and fail-safe operation.

Packages range from standard, single-cell marine units to sophisticated, offshore hazardous-area packages. Large-capacity units for power and industrial applications are also available.

Designed to operate at 145 psi [10 bar], tested to 220 psi [15.2 bar]; has withstood 580 psi [40 bar] during certification trials without leaks
Compact design reduces weight and space requirements.
Vertical orientation facilitates removal of hydrogen byproduct of the electrolytic process

SEA-CELL electrochlorinator concept and operation

The SEA-CELL electrochlorinator is an in situ sodium hypochlorite generator using saline water via electrolysis. Sodium hypochlorite is one of the most effective oxidizing biocides available.

Designed around a reliable, self-cleaning generator assembly, the SEA-CELL electrochlorinator uses a unique arrangement that encloses the anode-cathode bipolar plates within an leak-proof, integral housing. Unlike other cell designs that use the cathode or anode as the containment device for the process fluid, the SEA-CELL electrochlorinator ensures leak-free operation even in the event of an anode-cathode failure because the plates are mounted inside a substantial polypropylene container. This design is ATEX certified and ingress protection (IP) 65 rated. This eliminates the need for an additional enclosure, and allows installation in harsh marine environments.

This flow path is also self-cleaning, eliminating the need for acid cleaning. Instead, the cell plates are kept free of deposits and hydrogen is removed by optimizing fluid velocities.

The hypochlorite solution is stored in the disengagement tank under level control. The solution passes to the dosing point, where it is discharged to the seawater system by multistage centrifugal dosing pumps.

METROL SEA-CELL Electrochlorinator
METROL SEA-CELL Electrochlorinator

Hypochlorite generation process

The hypochlorite generation process is based on electrolysis of the sodium chloride in raw seawater as it flows between anodic and cathodic electrodes energized by direct current, and the successive chemical reactions that take place in the seawater between the products of electrolysis.

Passing direct current through an aqueous solution of sodium chloride causes the chloride ions to migrate to the anode and sodium ions to migrate to the cathode, leading to the generation of chlorine at the anode and hydrogen plus sodium hydroxide at the cathode.

Hydroxyl ions migrate from the cathode area and react with sodium ions and chlorine dissolved in the seawater near the anode to produce sodium hypochlorite