Page 49 - Industrial plants

SIL and IECEX certifications for SCAE:

Another success in automation

Performance and Control for an Electrochlorination package.
Electrical control cabinets with redundant PLC and diagnostic
made by SCAE

Roberto Manzoni, Systems and Automation Department, Manager
SCAE

lectrochlorination is the process of electrolyzer cell’s channel of decreasing thickness. One
producing hypochlorite by side of the channel is a cathode, the other is an anode.
passing electric current through salt A voltage DC current is applied, electrolysis happens
water. This disinfects the water and producing sodium hypochlorite and hydrogen gas (H2).
makes it safe for other plants or even for The solution travels to a tank that separates the
Ehuman use, such as for drinking water hydrogen gas based on its low density. Only water and
or swimming pools. ordinary salt, (sodium chloride (NaCl)) are used. The
In this project, Hypochlorite solution is produced by sea chemical reaction is really easy and adding the electrical
water electrolysis from Hypochlorite electrolyzers energy to sodium chloride in water, the result is the
(2x100%) fed from Transformer Rectifiers (2x100%). production of sodium hupochlorite and hydrogen gas.
The produced Hypochlorite is stored inside Hypochlorite Companies may use seawater for this process due to
degassing storage tank (1x100%) along with Hydrogen its low cost. The water used is usually brackish water
as process byproduct. Hydrogen released from or brine (i.e. a solution with >0.5% salinity). In these
hypochlorite solution is diluted by Ventilation fans cases, additional contaminant chemicals may be
(2x100%) and then vented to safe location. present in the water feed. The low voltage DC current
The process of electrochlorination is simple. It is still performs electrochlorination.
the electrolysis of saltwater to produce a chlorinated However, due to deposit formation on the electrode
solution. The first step is removing any solids from the surface, also the electrolyzer must undergo a periodic
saltwater. Next, the saltwater streams through an cleaning with diluted hydrochloric acid. Best frequency

IndustrIal Plants - May 2023
47