Lamellar water water-desalinating installation of firm "Alfa Laval"

Министерство Образования Украины

Азовский Морской Институт

Одесской Национальной Морской Академии

Пластинчатая водоопреснительная установка фирмы «Alfa Laval»

Lamellar water water-desalinating installation of firm "Alfa Laval"

Подготовили:

курсанты III-ЭСЭУ-I

Шиян А.В.

Мариуполь,2009

The JWP-26-C series covers a capacity range from 4 to 35 m / 24h, depending on the heating medium and cooling water temperatures. The shown capacities are at a cooling water temperature of32°C.

Distillers can be dimensioned to suit any jacket water temperature from 55-95°C and any cooling water temperature required. The quantity of fresh water C and any cooling water temperature required. The quantity of fresh water produced can be altered within each size by varying the number of plates in the heat exchanger assemblies

Application

Conversion of sea water into fresh water by vacum distillation for the supply of high quality fresh water for domestic and process utilization. For installation on ships and rigs* and remote onshore locations. The JWP-26-C is designed for automatic operation with continuous control of freshwater quality.

Features

* Simple, compact design

* Titanium heat exchanger plates and other seawater resistant materials (non-coated)

* Combined condensor cooling, ejector water and feed water system

* Freshwater control system

Benefits

* High quality freshwater, the low content of dissolved solids

(salinity) ensures the supply of pure water which can be used directly as make-up for steam boilers.

* Long lifespan. High grade, corrosion resistant materials, such as the titanium plates, ensure a long lifetime for the equipment.

* Low operation and maintenance costs. Start-and-forget operation, combined with the easy access to the interior, reduces man-hours required for operation and maintenance to a minimum.

* Simple installation due to compact design, low weight and the possibility to assemble on the spot.

Working principle

The feed water to he distilled is taken from the sea cooling water outlet of the condenser. It enters the evaporator where it evaporates at about 40 50 C as it passes between the plates heated by the heating medium.

The evaporating temperature corresponds to a vacuum of 90-95%, maintained by the brine/air ejector. The vapours generated pass through a demister where any drops of seawater entrained are removed and fall due to gravity to the brine sump in the buttom of the distiller chamber. The clean freshwater vapours continue to the condenser, where they condense into fresh water as they pass between the cold plates cooled by the sea cooling water. In order to check continuously the quality of the produced fresh water, a salinometer is provided together with an electrode unit fitted on the fresh water pump delivery side. If the salinity of the produced fresh water exceeds the permitted maximum value fl pprn/, the selenoid valve and alarm are activated to dump automatically the produced fresh water to the bilge.

Cross-section of the camera of the distiller N1 REX

1. Seawaterfeed

2. Heating medium in

3. Heating medium out

4. Sea water cooling in

5. Seawater cooling out

6. Fresh water out

7. Evaporated steam

8- Demister

9- Condenser

10. Evaporator

11. Brine out

Installation

The JW26-C freshwater generator is designed for automatic operation in periodically unmanned engine rooms and other automated operations.

The heating medium is either engine jacket cooling water or a closed circuit heated by steam.

The ejector pump is separately installed and has separate suction from the sea chest. This pump supplies coolant in the form of sea water to the condeser, feed-water for evaporation and water for the combined brine/air ejector. The fresh water produced is pumped to the tank by the built-on freshwater pump.

The separately installed control panel* with motor starters and salinometer, supplies electrical power to the ejector and fresh water pumps and control voltage to the salinometer and dump valve.

Basic equipment

Freshwater generator unit, including titanium plate exchangers for evaporator and condenser, distiller shell, two stage brine/air ejector, freshwater pump, freshwater control sensor and internal piping.

Additional equipment necessary for operation

* Combined cooling and ejector water pump with electrical motor

* Control panel with motor starters and salinometer

* Feed-water anti-scale chemical dosing unit (necessary at heating medium temperatures above 75°Q

Optional equipment

* Steam injector system type JWSP and SP

* Equipment for steam boosting and hot water loop system

* Extended control panel with motor starters and salinometer

* Freshwater pH adjustment (rehardening) filter

* Freshwater disinfection equipment

* Connections according to ANSI and JIS standard

Technical documentation

Complete information and documentation accompany each freshwater generator.

The Installation Manual gives all information necessary for correct installation:

* Plant description

* Installation

* Technical data and drawings

The Instruction Manual gives all information necessary for operation and maintenance:

* Plant description

* Operating instructions

* Chemical dosign of anti-scale chemicals

* Trouble shooting

* Maintenance of major components

* Spare parts drawings ¦Technical data and drawings

Alfalaval Freshwater Generator as an integral part of cooling water system

1. Alfa Laval Freshwater Generator

2. Diesel engine

3. Jacket water circulation pump

4. Thermostatic valve (too low temp, control)

5. Thermostatic valve (too high temp, control)

6. Jacket water cooler

7. Ejector/cooling water pump

8. Fresh water pump

9. Booster heater, optional

10. Hot water circulation pump, optional

11. Manual bypass valve

12. Fresh water storage tank

Starting procedure:

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

2. Open overboard valve for combined air/brine ejector.

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

4. Start ejector pump.

5. When there is a minimum of 90% vacuum, open hot water inlet and outlet valves /from jacket cooling system/.

6. Start hot water supply to evaporator section by adjusting by-pass valve, until the disired 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 / adjust by-pass / will cause the following effects:

a. in case the flow is too low - low boiling temperature, drop the fresh water production / high brine level in sight glass in separator vessel /

b. in case the flow is too big - high boiling temperature, drop of fresh water production, increase of salinity and drop of vacuum / low brine level in sight glass in separator vessel /.

7. Swith on salinometer.

8. Start fresh water pump.

During the first few minutes, after fresh water pump starts, salinity of produced water may be higher than 2 ppm, thus it is recommended to dump it to bilge / open valve on the discharge side of fresh water pump /. When evaporation starts, the boiling temperature rises, while the obtained vacuum drops to aprox. 90%. After few minutes normal vacuum and boiling temperature is re-established.

Stopping procedure:

1. Stop hoi water su p p ly to evaporator section.

2. Stop fresh water 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.

Main dimensions and service area

The designation, 80/100, in the type designation indicates the diameter of inlet and outlet flanges for jacket water and seawater connections.