ADVANCES IN WATER

DESALINATION TECHNOLOGIES WORKSHOP

Thermal Desalination Technologies

Saudi Aramco: Company General Use

Outline

- Major Thermal Desalination Plants Users

- Multi Stage Flash Evaporation Process

- Multi Effect Desalination Process

- Common operating problems and major challenges.

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Major Thermal Desalination Plants Users

Saudi Aramco: Company General Use

Thermal Desalination Processes

Designed to desalinate seawater to produce high quality water

(TDS < 5 ppm) that can be used as:

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Boiler Feedwater

Drinking water

Injected in Processes

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Multi Stage Flash Evaporators Desalination Plant, Dubai

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• Pretreatment System• Seawater intake

• Filtration

• Chlorination

•Multi Stage Flash Evaporation Main Components• Flash evaporators chambers

• Brine heater

• Ejector system for vacuum and removal of non-condensable gasses

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Multi Stage Flash Evaporators Process

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Multi Stage Flash Evaporators Process

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Multi-Stage Flash Evaporator

Stage Details

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Major challenges

Scale Buildup

Biofouling

Corrosion

Production Rate Product Water Quality

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Multi Effect Desalination Plant, Saudi Arabia

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1

2

3

4

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4321

1. Steam

2. NCG Removal

3. Cooling Water Out

4. Feed and Cooling Water In

5. Distillate Out

6. Brine Out

Multi Effect Distillation Process

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Major challenges

Scale Buildup

Biofouling

Corrosion Control High alloy Material Chlorination

Control High alloy Material Design Circulation FlowChlorination

Control Scale Inhibitor Design Circulation Flow Online chemical cleaning

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Multi Effect Distillation VS Multi Stage Flash Evaporators

Seawater

Seawater Steam

Steam

Low Temperature

Online chemical cleaning

High Temperature

offline chemical cleaning

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•Corrosion

•Scale Deposits

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Major challenges

Multi Effect Distillation Process

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Saudi Aramco: Company General Use

Materials of Construction

• Evaporator Shells – 316 SS or 317 SS

• Tube Sheets – 254 SMO

• Tubes – Ti gr2

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MED Scaling

•Outside of tube bundle

•Normally calcium carbonate with small amounts of calcium sulfate

• Follow by monitoring Gained Output Ratio (GOR)

•GOR = lbs of water producedlbs of steam consumed

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Evaporation Stages Material of Construction

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Cleaning Methodology

• MSF –

Online by ball cleaning

Offline with sulfamic acid

• MED –

On-line – increase antiscalant dosage and

reduce load

Offline – Sulfamic acid

Offline – Tetra sodium EDTA

Saudi Aramco: Company General UseCOE 202.07 22