Desalination of sea water by reverse osmosis using tubular module

Desalination of sea water by reverse osmosis using tubular module

235 Desahatim, 23 (1977) 235-243 8 Ekvier Scientific Pubbsbiag Company, Amsterdam -Printed DESALINATION OF SEA WATER in The Netbedsnds BY REVERS...

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235

Desahatim, 23 (1977) 235-243 8 Ekvier Scientific Pubbsbiag Company, Amsterdam -Printed

DESALINATION

OF SEA

WATER

in The Netbedsnds

BY REVERSE

OSMOSIS

USING

TUBULAR

MODULE

HIDE0

TSUGE+

, CHOTA

YANAGI

Mechanical Engineering Kobe (Japan)

AND

Research

KENJS

MORI

Laboratory.

E&be Steel,

Ltd.,

SUMMARY

In the process usually

pretreated

prevent

fouling

of desalination

to keep

by reverse

membrane

of membrane,

osmosis,

perfomance.

removing

raw

For

of suspended

sea water

example,

solid

to

is usually

recommended. In this first

stage

using

NRO

study,

to simplify

membrane tubular

module

membranes

was made

membranes

of di-

with similar

ones

removing

performance end three

from

types

cellulose

of suspended

system

was

of membrane.

diacetate And also

and trf -acetate. taken

process

in two stige

by

One of these

and others these

solid,

sutdied

were

data were

blended

compcred

with NaC1 solution.

INTRODUCTION

The advantages for desalination cross

section

primarily

ease

9

of the tubular

fouling

of physicai

present

result

and its uniformity

characteristics of ninimal

of tubular

ad&e~s:

tendency, in situ

reverse from

the large

module

module

cleaning

yield,

with proper

fractional

recovery

of the membrsne Ltd.,

Fukiai-Iw

configurations

characteristics

in the flow direction.

higher

Kobe Steel

osmosis

These

design. operation,

surface

Kobe.

fluid

flow

inherent advantage and

in comparison

Japan-

is

with other reverse

configurations

osmosis This

stage

feed

study

treatment

tubular

EXPERIMENTAL

brane And

were

with those

operation

wus carried

this

chemicals.

basic

engineering

data for

at minimized

first

pre-

pressure

with NaCI

aqueous

aqueous salt

filter

collected

were

solution

analysed

was

and sea water.

long

coefficient

was

from

used

term

and change

surface.

the membrane

sample

was

and residue

dried

absorption

were

as pretreatment.

filtered

by atomic

on mem-

of sea water

Continuous

the flux decline

solution , collected Each

solution

rejection)

solution.

cartridge

matter

and concentration

and dissolved was

deter -

spectrophotometer

and chromium.

Through

the experiment

(Cellulose

the hydrolysis

NRO-A

di and triacetate

The pH of sea water

3.

completely.

coefficient

(especially

fouling

the cleaning

NRO-B

studied

100 micron

operation

Pihrltes

rate.

out to obtain

and 50 -

To select

with iron

flow

of NaCl

to various mind.

to obtain

system,

module.

characteristics

compared

After

out

and flux decline

of feed

performance

of rejection

to be clarified

in this

PROCEDURES

effects

desalting

not need

carried

system

using

The

dose

was

of two-stage

Consequently,

of membrane.

was

controlled 1) of membrane.

(Cellulose

blended

diacetate

membrane)

by hydrochloric

membrane)

modules

acid

were

to about

and used.

6 to avoid

EQUIPMENT

Modules The NRO Ltd.

modules

and Nitto Electric Eighteen

length,

connected

in series length,

surface

is 1.75

were

to form

meter.

developed

by Kobe

Steel

Co.

inch in diameter module.

11 centimeter

square

which

fiber-glass-reinforced

one-half

2.6

used,

Industrial

of bored

nominally

meter

were

epoxy

Modules

outdiameter,

tubes,

with turbulence generally and its

are

effective

2.5

meter

promoter

in

are

fabricated membrane

in

za7

Salt 5000

ppm.

Reverse

rejection &cl

of membranes

feed

solution

was

about

and 42 Kg/cm2

98% under applied

the condition

of

pressure.

osmosis Schematic

the concentration

flow diagram of feed

water.

of apparatus

are

shown

in Fig.

concentrate

was

returned

1.

to feed

To control tank.

T Fig. 1 RESULT

Effect

AND

of feed

!WamaticdCqramoftestaqoipmant

DlsCUSSION

flow

rate,

concentration

and anplied

pressure

on membrane

nerforrnance Effects formance

are

flux and salt remarkable. higher high-salt usudly

of flow shown rejection Hence

concentration rejection lowR.

at this

rate

in Fig.

and concentration As

2.

decrease, the higher permeate.

membranes condition

of NaCl

increasing especially

recovery And should

more

feed

concentration,

the effect ratio at first

to lower

stage

of modules

As

perproduct

on the later induce

the concentration

be required.

number

on membrane

is the

of permeate.

flux of these should

is

be required.

N&I

-a4n

Feed flow Fig. 2

rate

04 fed (Iimin):

mfn

A : 1.4.

fXf e : 1.0,

o

: 0.6

ion and feed flow Effect of feed canon podilct flux and ralt r.$ection

Feed @3ncnCdOIX Feed flow rate Fig. 3

5

4

1

Effect of operating and salt rejection

4%

:

h2.

rati

tia)

2Sllmin

pressure an

product

flux

239

In Fig. of feed

flow

le/min.

increase curve tr2tion

of feed 3,

stage

drop

performance 2re

on salt from

pressure

performances

2nd NRO-B

triacetzte.

of pressure

2), 0.7-c

rate.

however, So,

with the increase

2

shouId

is shown

improved

rejection

point

of view

be over

linearly inclination

in

with of

of the concen-

46 kg/cm2.

material

Membrane NRO-A

the effect

on membrane

46 kg(cm2, operating

flow

is improved

flux and rejection

pressure,

over

of permeate.

Membrane

as feed

the product

easy

to avoid

concentration

of operating

turns

performance

But in order

is recommended

In Fig.

3.

the membrane

rate.

Effect Fig.

2,

are

respectively.

membrane

because

0.04

made

from

NRO-B

cellulose was

of its higher

more

and NRO-8 diacetate suited

are

Camcarbon

shown

and cellulose

than NRO-A

rejection.

i

ai

Fig. 4

of NRO-A

of diacetaae and Mend membranes

in Fig.4. di-

for first

240 Comparison desalting

between

To apply desalination sea

water

The

of sea water. was

data

and NaCl

taken

aqueous

solution

on

the relation

results

is obtained

sea

These

NaCl

chamctmirlia

water

relations

are NaCl

than

are

expressed

= 1.154

F (NaCl)

- 0.011

R (sea

water)

= 0.842

R (NaCl)

+ 15.7

F (sea

water);

R (NaCl)

stage

Flux ; Flux

water);

of sea water of

Rejection : Rejection

performance

to between

NaCl

of a33 rratar end f&Cl Oohrtion

solution

water)

R (sea

solution

characteristics

summA rized

F (sea

F (NaCl)

aqueous

of separation

of such experiment with

from

investigated.

Relationship of demhtti~

in conductivity.

First

of sea water

the standard

and NaCl

Fig. 5

result

effect

characteristics

of sea water of NcCl

(1)

____-_____-

(2)

day)

solution

(m3/m2

(‘%) solution

Better

equations.

----------

aqueous

5.

concentration

ty following

(m3/m2

aqueous

in Fig.

at same

(%)

day)

z

¶5-

d

I’

2” =5

.

.

The

0~0

O

of

results

concentration

micron

filter

was

and flux decline

1000

0

0

0

0

.

of modules used

0

0

0

0

0

hours operation

of sea

Concentration

Fig. 6.

93%

0

=

;QlS 5 o” 3 EQlO-

mean

.o”

water

was adjusted

in practical

m was

to about

0.076.

The

flux salt

module

was

are

4% which In this

equipment. initial

for pretreatment,

coefficient

with NRO-A

shawn

is expectedas

operation.

0. X6 m3/rn2

rejection

1.

Performance k eed Sea Water Turbidity

0.4

(ppm) 43.780

Conductivity

Product 1st Stage to.2

2nd Stage co.

2

220

5.940

(iW M alkalinity

(ppm

CL-

(ppm)

S042-

(ppm)

NO;

(ppm)

T -+“e

(PPm)

NP K TDS

415 0.3



0.05 0. a8 10,200

F,, m (ppm)

375 34,200

0 (2.0 128

(3.0

<3.0

;=0.2

to.2

2.2

2s SK+)

Mn

1,820

16.300

(ppm) (ppm

< 3.0 26.8

5,350

T hardness

SiO2

98.6

as CaCO3)

0.4

0.05

<0.03


03

co_02

to.

02

860 72.5 3.040

18.6 2.4 -=50

50

day

decreased

to 91%.

TABLE

in

from

242 The series

analysis

of NRO-B

operation,

of product

modules

100 micron

shown

in Fig.6. observed.

tion using

fitter

As

tubular

was

a result

in Table

50% recovery The

used.

100 micron

of use

module,

with pH adjustment

shown

at 40 -

In spite

hardly

is

of Fig.6.

using

was carried

results filter,

of sea

50 -

with

out.

of this

operation

1. in sea water

100 micron

3)

three

En this

the flux decline

and Table

the pretreatment

and filtration

Operation

1.

water

are

wzs desalina-

can be simplified

microstrainer

or

filter.

Selection

of cleaning The

hours

brown

was

25 -

Major

solved

analysis

cleaning

quantity

deposit

metallic were

Na.

solutions and Cr

of Fe

by treatment

and citric

TABLE

observed

was

on the membrane

compornents

of the deposit

.4) , K, Sl

and Cr.

Fe5)

after

500

by emission

and its ignition

loss

acid

for

into cleaning

summa

are were

the deposit

rized

effective

were

solutions

in Table2.

The

investigated. and the weight

Sodium

loss

dichionate.

disof

oxalic

chemicals.

2.

Solubility

of membrane

foulant

to chemical

solution

Solution No. 1

Water

2

HCI

3

Citric

4



acid *

5

Ammonium

6

Oxalic

7

EDTA

+

Each

500mg

for

30 min.

(mol/k’)

Fe

6.70

Cr

1.11

2.28

% 11.6 13.2

2.00

2.20

2.10

2.20

114.

17.5

26.0

2

0.0952

4.00

4.00

189

34. 3

38.7

0.0952

5.00

5.05

155

64.0

35.3

0.0952

4.00

4.30

256

39.2

45.3

4.00

4.85

278

22.0

31.5

added

and fzltered

5.85

0.28

0.0952

2

was

Filtrate

0.01

*

scale

Solution 5.40

2

citrate

acid

ton Content in Scale filtrate mp/& 106s

PH (wt%)

mixed

surface

31%.

The

acid

deposit

operation.

spectroscopic

solution

to 500 ml prepared

under

reduced

solutions

pressure.

respectively,

245

Filter

;

*

pH of prepared

The

0.2

micron

Sartorius solution

membrane was

filter

controlled

with HCi or NaOH

REFERENCES

1. 2.

I. NUSBBAUM. A.P.HATCHER K.D.VOS, Desalination. 5 (1968) 157. H. OHYA, T. MORIYAMA, S. SUmEQ AND

AND

F. 0. BURRIS

S. ISHIZAKA,

Jr.,

Desalination,

4.

16 (1975) 235. K. C. CAA?ABASAPPA AND J. J.STROBEL. 5th International Symposium on Fresh Water from the Sea, 4 (1976) 267. 63 J. W. MCCUTCHAN AND J.S. JOHNSON, Chem. Eng. Progress,

5.

J(*967) . M. JACKSON 9o -

3.

AND

D. LANDOLT,

Desalination,

12 ( 1973) 3 61.