Procedure for Operating the FWG plant with plate type heat exchangers

Starting procedure:

1) Open valves on the suction and discharge side of the ejector pump

2) Open overboard valve for combine air/brine ejector

3) Close air valve on the upper part of the separator vessel

4) Start ejector pump. Check the pressure before ejector (min 2.8…3 bar) and after ejector (max 0.6 bar) (see figure "vacuum creation")

5) When there is a minimum of 90 % vacuum, open hot water inlet and outlet valves/from jacket cooling system (see figure "Hot water supply")

6) Start hot water supply to evaporator section by adjusting by-pass valve, until the desired jacket water temperature is reached (inlet 75 ˚C, outlet 60 ˚C). The boiling temperature inside the separator vessel ought to be about 40 ˚C. Improper hot water flow (adjusted by-pass) will cause the following effects:

a. in case the flow is too flow – low boiling temperature, drop the freshwater production (high brine level in sight glass in separator vessel)

b. in case the flow is too big – high boiling temperature, drop the freshwater production, increase of salinity and drop of vacuum (low brine level in sight glass in separator vessel)

7. Switch on salinometer (see figure "Evaporation – freshwater production")

8. Start freshwater pump (see figure "Evaporation – freshwater production"). During the first few minutes, after freshwater pump starts, salinity of produced water may be higher than 2 ppm, this it is recommended to dump it to bilge (open valve on the discharge side of freshwater pump). When evaporation starts, the boiling temperature rises, while the obtained vacuum drops to approximately 90 %. After few minutes normal vacuum and boiling temperature is re-established.

Schematic diagram of the FWG plant with plate type heat exchangers

Legend of the Schematic diagram of the FWG plant with plate type heat exchangers

Starting procedure of the FWG plant with plate type heat exchangers (Vacuum creation)

Starting procedure of the FWG plant with plate type heat exchangers
(Hot water supply)

Starting procedure of the FWG plant with plate type heat exchangers
(Evaporation – freshwater production)

 

Stopping procedure:

1. Stop hot water supply to evaporator section

2. Stop freshwater pump

3. Switch off salinometer

4. Stop ejector pump

5. Open air valve

6. Close valves on the suction and discharge side of the ejector pump

7. Close overboard valve for combined air/brine ejector