SEA WATER Presentation

8/13/2019 SEA WATER Presentation

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HCl Al2(SO4)3.14.3H2O

SBS

Disinfection pH

adjustment

Anti-scalant

addition

Media Filter

Coagulation

unit

Cartridge

Filter

Disinfection

(Chlorination)

De-Chlorination

unit

Neutralization

pH adjustment

Storage

Tank

ROMembr

an

e

NaOCl

Hypersperse AS110

HPP

NaOHNaOCl

Pump


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Used to prevent reverse osmosis membrane from fouling by

removing large percentage of suspended solid from feed water

SDI measurement commonly used to indicate the effectiveness

of media filter

Almost, all RO membrane manufacture recommends SDI to be

less than 3


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[Ksp] =

2.44 x10-5[Ksp] =

1.05 x10-4

93.176 L/day

[Ca+2] x [SO4-2]= 4.23 x 10-4mol/L

Ksp= 2.44 x 10-5

The equation of calulating the dose rate

Antiscalant (Hypersperse AS110)


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Plant SDI before

cartridge

SDI after

cartridge

Al Jubail, Saudi Arabia RO

desalination plant

3 2.8

Singapore pilot plant 6.5 6.1

desalination plant at Larnaca,

Cyprus

3 2.8

in

outin

SDI

SDISDIremoval

%

%6removal


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%6removal


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Normally, the available free chlorine concentration before RO

membrane is 0.5 1 ppm.

The maximum allowable chlorine concentration before RO

membrane is 0.05 ppm.

Residual free chlorine can be removed by:

adsorption onto activated carbon media filter

chemical reducing agent (SBS)


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Sodium Bisulfite can be formed by dissolving Sodium

Metabisulfite (SMBS) in water

In practice, designers used to add 3 mg/L of SMBS of chlorine

Total amount of free chlorine in water = 503 * 106mg /day

32522 2NaHSOOHOSNa

In theory, 1.34 mg of SMBS will remove 1 mg of free chlorine.


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The amount of SMBS needed to remove free chlorine =

7968.22 mole/day

The dosage rate of SBS needed to remove residual chlorine =

205.58 gal/day

The amount of moles of Sodium Bisulfite needed to remove the

free chlorine = 15,936.13 mole/day

SMBS

H2O SBS


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Q6

Stage 1 Stage 2Q1 Q2 Q4

Q5Q3

RO membrane


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Parameters Value

Overall Recovery% 30%

Recovery for second stage 85%

Salt rejection % 95%

Total product 40MGD

Total dissolved solid for total product 170 ppm

Total dissolved solid for feed 43153ppm


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100%covRe rateflowfeed

rateflowPermeateery

Q2=47 MGD

Q6

Q1 Q2 Q4

Q5Q3

ionconcentratsaltfeed

ionconcentratsaltpermeaterejectionsalt 1

TDS2= 2156.79 ppm


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Material balance on firs t stage:

ppmTDS

QTDSQTDSQTDS

654883

321

Q6

Q1 Q2Q4

Q5Q3

554422 TDSQTDSQTDSQ

TDS5=13415 ppm

Mater ia l balance o n s econd stage:

664411

TDSQTDSQTDSQ

The overal l salt balance for the sys tem

TDS6= 61550.46 ppm


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Added for pH adjustment to minimize the corrosion in the

product water pipes

The calculation was based on

The required pH for drinking and potable water is in the range

of 6.5 9.5

Neutralization of acid

Adjust pH from 7 to 8


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Capacity of each filter = 600L/min

number of filter = 582 filter

349 x 103L/minFeed flow rate =

feed water flow rate / filter capacity

= Number of filter element

Filter cartridge/ vessel = 26Number of vessel = 25

( 23 in operate + 2 standby)

P = 4 psi per 1 m3/min

The feed flowrate inter each vessel= 15 m3/min

TotalP = 15 x 4 = 60 psi = 4 bar


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number of module =

min19modGallon

Q ule

min92361

GallonQfeed

4861

mod

ule

feed

Q

Qmodule


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number of configuration = 203 configuration


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ions C (mg/l) C (mol/L)

Mg+2 829.35 0.03412

Ca+2

488 0.0122

Na+ 13160.22 0.572

HCO3_

115.9 0.0019

SO4-2

3473 0.03617

Cl- 23811 0.6726


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32899.1 im

iosm mTP 27319.1

psiPosm 28.471

For feed

elementAreaelementmembranefluxQ vesselper #,

vesselsper

stageper

QQvesselsofNumber

,

1,

6 vesselsofNumberelementofNumber


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properties Stage #1 Stage#2Permeate flow 47 MGD 40 MGD

Qper,vessel 2755 L/h 2755 L/h

# of vessels 2690 2290

# of element 16140 13740


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One vesselsFeed

Permeate


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7.1

01.0 fcfc qnq

2

f loweconcentratf lowfeedqfc

The calculations of pressure drop in RO membrane

vesselsoneperpsiqfc 7.1738.28601.0 7.1


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1. Chemicals

Sodium Hypochlorite

Antiscalent

Hydrochloric acid (HCL)

Sodium bio-sulphate Coagulant (Aluminum sulphate)

NaOH

2. Process

MMF

Membrane

Desalination plant Intake

3. Products Brine


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1. Chemicals

2. Process

Sand filter

Advantage:

Sand work as a filter

Disadvantages:

Need higher pressure Limits on flow rate

Cost


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1) Mix brine with seawater beforedischarge.

3. Products

2) More than one discharge.

These are located a way of each other at a distance.

RO

plant

Feed seawater

To

seawater

5) Deep well disposal

3) Mixing brine water with cooling water comingfrom adjacent power plant.

4) Evaporation ponds


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PID Before HAZOP


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HAZOP analysis on water feed entering multi media filter. (Line no. 2)

Guide

Word

Deviation Causes Consequences & Action

NO FLOW Pump failure

Ruptured (broken) pipe

Valve (V2) shut

No product

oCheck valve

oCheck & Repair pump and pipe

oPut flow indicator (FI 2)

LESS FLOW Pipe leakagePump failure

Low production qualityLess feed pressure

Slow operation

oCheck & Repair pump and pipe

MORE FLOW Damage pump The multi media will be shutdown.

The ratio between feed water and

coagulant is not the same

Need to fix coagulant dosingThe efficiency of media filter will

decrease.

The suspended solid will not be

removed

Lower the product quality

Over flow

Lower removal capacity

oCheck & Repair V2


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PID After Hazop


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Documents

SEA WATER Presentation