Multi stage flash type evaporators are usually found in huge powerplants.So here is one of the application of multi stage flash type evaporators in the marine industry

2. THE EQUIPMENT USED ON BOARD FOR THE PRODUCTION OF FRESHWATER FROM
SEAWATER FOR THE USE OF DOMESTIC AND AUXILIARY PURPOSES
A CONSIDERABLE AMOUNT OF FRESH WATER IS CONSUMED IN A SHIP. THE CREW
CONSUMES AN AVERAGE 100 LITER/HEAD/DAY.
IN A STEAM SHIP, THE CONSUMPTION OF THE BOILER CAN BE UP TO 30 TONNES/DAY
• VARIOUS TYPES OF FRESH WATER GENERATORS USED ON BOARD SHIPS ARE MAINLY:
• SUBMERGED TUBE TYPE FRESH WATER GENERATOR
• PLATE TYPE FRESH WATER GENERATOR, AND
• REVERSE OSMOSIS PLANT

3. • IT WAS INVENTED IN 1950.
• ACCOUNTED FOR 85% OF THE WORLD’S PRODUCTION OF
DESALINATED WATER
• FIRST PLANT OF MSF WAS BUILT IN 1957 IN KUWAIT.
• MSF IS THERMODYNAMICALLY INEFFICIENT PROCESS.
• MSF IS MATURED AND MOSTLY USED IN MIDDLE EAST REGION.
• CAPITAL COST IS US$ 5-6 PER INSTALLED GALLON/DAY.
• DESALINATED WATER COST IS US$ 0.8 TO 1.5 PER CUBIC METER.

4. WHAT IS MULTI STAGE FLASH TYPE FRESH
WATER GENERATOR?
• MULTI-STAGE FLASH DISTILLATION (MSF) IS A WATER DESALINATION PROCESS
THAT DISTILLS SEA WATER BY FLASHING A PORTION OF THE WATER INTO STEAM IN MULTIPLE
STAGES OF WHAT ARE ESSENTIALLY COUNTERCURRENT HEAT EXCHANGER.
• MULTI-STAGE FLASH (MSF) DISTILLATION PROCESS HAS BEEN USED FOR MANY YEARS AND NOW
IS ONE OF THE LARGEST SECTORS IN THE DESALINATION INDUSTRY.
• MULTI-STAGE FLASH DISTILLATION PLANTS PRODUCE ABOUT 60% OF ALL DESALINATED WATER
IN THE WORLD NOW.
• MULTI STAGE UNITS WITH EACH STAGE MAINTAINED AT A LOWER PRESSURE ALLOW IMPROVED
EFFICIENCYAND HIGH OUTPUTS.

6. • MULTISTAGE STAGE FLASH DISTILLATION FOR DESALINATION IS CARRIED OUT
IN A PRESSURE VESSEL THAT IS DIVIDED INTO NUMEROUS SECTIONS THAT
HAVE DECREASING PRESSURES AND TEMPERATURES.
• THE SECTIONS EACH HAVE A SET OF COILS THAT HAVE SEAWATER PUMPED
THROUGH THEM.
• THESE COILS SERVE TWO PURPOSES: CONDENSING THE STEAM PRODUCED
BY THE FLASH EVAPORATION AND PREHEATING THE SEAWATER TO ALMOST
THE REQUIRED TEMPERATURE FOR DISTILLATION.

7. • THE SEAWATER THEN PASSES THROUGH AN INLINE STEAM HEATER, TAKING IT UP
TO A TEMPERATURE BETWEEN 70ᴼC AND 100ᴼC; THE SEAWATER NOW BEING
CONSIDERED TO BE BRINE. MULTI-FLASH DISTILLATION PLANT ENGINEERS WILL
SOMETIMES REDUCE THIS TEMPERATURE TO DECREASE THE FORMATION OF
SCALE.
• THE BRINE NOW PASSES INTO THE DIFFERENT STAGES AND, AS IT IS AT A HIGHER
TEMPERATURE THAN THE SECTIONS, SOME OF IT FLASHES TO STEAM. THIS IS
CONDENSED BY THE SEAWATER COILS AT THE TOP OF THE SECTIONS, WITH THE
CONDENSATE DROPPING DOWN ONTO THE COLLECTION TRAYS UNDER THE
COILS.
• THIS CONTINUES TO THE FINAL STAGE WHEN THE BRINE IS PUMPED TO WASTE
AND THE COLLECTED DISTILLED WATER IS DELIVERED TO STORAGE TANKS.
THERE IS A SALINOMETER ON THE DISCHARGE LINE TO THE STORAGE TANKS

11. • MSF TYPE IS COMMONLY USED IN PLANT SECTOR FOR PRODUCING LARGE
AMOUNT OF WATER.
• FIRST TYPE OF MSF TYPE FRESH WATER GENERATOR FOR BEING USED ONBOARD
IS WARTSILA SERCK COMO 2014.
• CAPACITY UP TO 1500 T/DAY.
• EITHER STEAM, ENGINE JACKET OR A COMBINATION OF THIS CAN BE USED FOR
HEATING PURPOSES.
• STEADY PRODUCTION OF SEA WATER WITH TEMPERATURE FROM 0-32 DEGREE
CELCIUS
• NOT YET BEING APPLICABLE TO OTHER TYPE OF SHIPS OTHER THAN CRUISE
SHIPS (QUEEN VICTORIA, CORAL PRINCESS, OASIS OF THE SEA)

13. WARTSILLA SERCK COMO

14. MAINTENANCE
&
TROUBLESHOOTING

16. HOW DOES PRESENCE OF SCALING
AFFECTS THE PERFORMANCE OF MSF TYPE
DISTILLATION
THE PRESENCE OF SCALING DIRECTLY INVOLVES THE FOLLOWING EFFECTS:
• 1)FORMATION OF INSULATING FILM, THAT CONSTITUTES AN ADDITIONAL
RESISTANCE TO HEAT TRANSFER, THUS RESULTING IN A REDUCTION OF PLANT
THERMAL EFFICIENCY;
• 2)NARROWING OF PASSAGEWAYS, THAT MEANS EITHER A FLOW RATE
REDUCTION FOR THE HIGHER HEAD LOSS IN THE TUBES OR AN INCREASING IN
ENERGY CONSUMPTION TO KEEP THE SAME FLOW RATE;
• 3)RISK OF CORROSION UNDER DEPOSITS, WITH THE CONSEQUENT RISK OF
PITTING PRIMING

18. 1. LOW PRODUCTION OF WATER
2. SALINITY TOO HIGH
3. ABNORMAL AMPERAGE CONSUMPTION OF BRINE PUMP
4. LOST OF VACUUM IN PRESSURE CHAMBERS
5. COIL DAMAGES
6. TEMPERATURE ON HEATER NOT UP TO OPTIMUM LEVEL
7. SEA WATER COOLING TEMPERATURE AND FLOW LOW
8. SCALE FORMATION INSIDE THE COIL
9. LEAKAGES

19. • PRESSURE TEST OUTSIDE THE TUBES
• FITTING DEMISTER CORRECTLY
• CLEANING/REPLACING ELECTRODE
• EXAMINE WITH STATOSCOPE AND REPLACE BEARING IF DEFECTIVE
• CLEAN SUCTION STRAINER
• CLEANING COILS IF THERE IS SCALE FORMATIONS
• CHECK MAXIMUM CLEARANCE FOR PUMPS
• CHEMICAL WASH

20. 1. CHECK ALL VALVES TO MAKE SURE NOT TO SEIZE
2. CHECK OVERBOARD PIPELINE AND VALVE
3. GREASING VALVES
4. INSPECT FOR LEAKAGES
5. TESTING HIGH SALINITY ALARM

21. ADVANTAGES AND DISADVANTAGES
ADVANTAGES DISADVANTAGES
reliable and durable significant environmental
impact
cheap and fairly easy plants cannot be operated below 70-80% of the
design capacity.5
produces high quality water MSF plant will generally
recover no more than 10% of the feed water
The heat-recovery system increases efficiency unacceptable to consumers because of its flat,
insipid taste; it is also often corrosive to water-
supply systems

22. REFERENCES
• HTTP://MARINEENGINEERINGONLINE.COM/FRESH-WATER-GENERATOR-OR-EVAPORATOR-ALFA-
LAVAL-TYPE/
• HTTP://WWW.MARINEENGINEERING.ORG.UK/PAGE50.HTML
• HTTPS://EN.WIKIPEDIA.ORG/WIKI/FLASH_EVAPORATION
• HTTP://WWW.BRIGHTHUBENGINEERING.COM/STRUCTURAL-ENGINEERING/109915-MULTI-STAGE-
FLASH-DISTILLATION-FOR-DESALINATION/
• HTTP://WWW.BRIGHTHUBENGINEERING.COM/POWER-PLANTS/29623-HOW-DESALINATION-BY-
MULTI-STAGE-FLASH-DISTILLATION-WORKS/#IMGN_0
• FILE:///C:/USERS/DOWNLOADS/PBS_DISTILLER%20(INLAND).PDF
• HTTP://WWW.SIDEM-DESALINATION.COM/PROCESS/MSF/

23. • PHOTO COURTESY OF WWW.SEPARATIONPROCESSES.COM
• HTTPS://SITES.GOOGLE.COM/SITE/KJDESALINATION/VACUUM-DISTILLATION
• HTTPS://BOOKS.GOOGLE.COM.SG/BOOKS
• HTTPS://WWW.DESLINE.COM/GENEVA/BANAT.PDF
• MARINE AUXILIARY MACHINE,7'TH EDITION, H.S.MCGEORGE,C.ENG,FIMAREMRINA,MPHIL
• MODERN MARINE ENGINEERS MANUAL,VOLUME 2,ALAN OSBOURNE,U.S MARITIME
COMMISION
• INTRODUCTION TO MARINE ENGINEERING,SECOND EDITION,D.A TAYLOR

24. THANK YOU! 