The project involved the replacement of a mercury cell chloralkali plant with a new membrane plant. The new membrane plant was built adjacent to the mercury plant so that the rectifiers could be re-used. Noram’s scope of work included:

· Design and programming of a PLC based control system with hot-standby
· Replacement of controls for 5 existing diode rectifiers rated 65 kA, 180VDC
· Specification and procurement of new saturable core reactor power supplies
· Control of DC switches on 24 parallel electrolyzers
· Monitoring of 24 current shunts and overload protection for electrolyzers
· Input of metering information from 8 Power Meters (IEDs) on 13.8 kV feeders
· Communication interface with Fisher Provox DCS
· Enabled savings of approximately 10% of total capital cost

The rectifier control system was installed and tested on the rectifiers while the mercury plant was still in operation. The transition to the membrane plant was seamless.


Existing rectifiers with new 330kA buswork:

New cooling and control cables. Space for a 6th rectifier.

New bus installed during 4 week shutdown. Mercury cell plant disconnected.

New rectifiers controls:

Rectifier controls available on DCS. Duplicate controls hardwired on for console for fast access and safety.

New PLC based controls for 5 rectifiers. New saturable core reactors power supplies on top. Lockout and O/C relays reused.