Procedure for operating FWG membrane type

Schematic diagram of the WatMan RO 45000 SW 2-pass FWG plant shown in figure below.

 

BEFORE START

- Check antiscalant level in chemical dosing unit tank (T4.0) and top up if low
- Check NaHSO₃ level in chemical dosing unit tank (T2.0) and top up if low
- Check that inlet valve and overboard valve are open
- Vent air from system after maintenance work

 

START-UP

- Flush the inlet water piping thoroughly before the system start-up. Heavy scale or sediment can permanently cover or foul the filter media and the cartridges

- Check the coarse strainer in the hull chest

- Check that all components are in “Automatic” mode.

- Start the system by pressing the system “Start” button. If any problems within the start-up sequence, press the “Stop” button

Schematic diagram of the WatMan RO 45000 SW 2-pass FWG plant

When started in automatic mode the system will carry out the pre-programmed start-up procedure.

 

Main phases of start-up procedure (see figure above)

1. Seawater pump CP1.1 and chemical dosing pump MP2.1 start

2. Forward flushing of multimedia filters F3.1-F3.6

3. Flushing of RO system.

4. 1st pass high pressure pump CP6.1 and antiscalant pump MP4.1 start

5. 2nd pass high pressure pump CP6.3 start

 

Adjustments

The control system does the necessary adjustments during operation automatically.

The default flows and pressures are as follows.

Fresh water flow 44,6 ± 0,5 m³/h

1st pass permeate flow 50 + 1 m³/h

Reject (concentrate) flow 63 ± 2 m³/h

Feed pressure 48 ± 5 bars

Depending on the water temperature and salinity

 

DURING OPERATION

- Record operation parameters daily

- Check alarms. If any, find the root cause and eliminate it immediately

- Check normalized flow. Prepare for Clean-In-Place (CIP) procedure if too low

- Check bag filter pressure loss. Change filter bag if too high

- Never close valves manually during production

- Never run the system without antiscalant

 

BEFORE STOP

- Always stop the system before closing overboard valve or inlet valve

- If a longer shut down period (> 1 week) is expected preserve the system. For shorter stop daily flushing is enough.