Waste heat powered reverse osmosis plants

Desdination.39(1981)137-145 ElsevierSciedificPublishingCompany. Amsterdam-RintedinTheNetherIands

WASTE

HEAT

POUERRD

REVERSE

by R. A. Tidball

OSMOSIS

and

137

PLANTS

R. Kadaj

ABSTRACT The

purchased

greatly gas

power

reduced

turbines,

to convert The

flare

low

system

reduce

the

The

can

etc.

waste

heat

be designed of

the

flashing

a superheated coupled

and

a hydraulic

turbine

can

be combined

into

This

Performance

paper

from

duce

750

purchased

describes

of 400

pover

A drscussion ature

Levels

obtained

to

one

per

using

the

heat

from

from

by using

existing

in new

can

be

diesel

engines,

a Brphase

turbine

phase

to the

electrical

from

stream

turbine.

or

The

the

or

waste

hign

generated

The

generator

is discussed. energy

installations

to

supplies.

by a two

a nozzle

to an

design

of a seawater

generatcng

water

cubic

by

turbine

can

be

to a combination

heat

pressure

recovery

of

turbine

concentrated

brine

reverse

unit.

at an energy

The

osmosis

SeaRO

consumption

system

system

using

is designed

of approximately

waste to pro-

2.5

KrJH of

and

temper-

meter.

the waste this

waste

through

systems

heat

system.

of available of

osmosis waste

horsepower.

is driven

recover

reverse

reclaiming

‘an be accomplished

turbine

diesel ppm

of

by

equipnent

shaft,

of the

an existing cmd

to use

Liqurd

tvo.

This

turbine

to a pump

the

operation

to shaft

generating

conservation

directly

heat

for

eliminated

gases,

Level

size

Biphase

required

or sometimes

desalination heat

system

and

source

capacity

at various

is presented.

a conventional

quantities

A comparison

electrical

drive

of water

costs

is presented.

INTRODUCTION -~ The high by

power

the

costs

versus

of the

operating

seawater elements

usually

forces

osmotic

pressure,

salinity

exceeds the of

*Jaste brine this

high

as

and the

This

Since

salrnity

costs.

the

at

as well

45.000

recovery the

contains

pressure

feed

vacer

with systems

same

the

results

of the

feed

seriously time

final

and

vith

osmotic

in product

the

the

recovery

the

of

of the

the

as high

osmotic

brine

Lov as 20%

pressure

the

reverse

pernxate.

to maintain

of as

(30,000

recoveries

productivity

pressure

of capital

Low salinities

product

quote

is caused

optimization

salinity

recoveries

is generally

variation

increases,

reduces

product

the

relatively

water

increases the

systems This

This

the mean to acceptable

when

the

seawater

mg/L.

plants

a relatively water

osmosis gallons.

to operate

of product

seavater

the

to reduce as

reverse

thousand

In seavaters

which

the

designer

sometfmas

of

salinity

increases,

osmosis

lex*els.

seawater

f.5 KU?L per

it is possible

However,

pressure

30 to

in the

mg/L),

35%.

to operate

from

variations

to 35,000 as

required

-- ranging

from

the

is quite high

in a power

seawater high

amount

recovery

is Lou and

(55 bars of energy. turbine,

since

or higher) Utilizing

allovs

the

the the

operating discharged

the energy

recovery

in

of 30 to

TIDEALL

138

35X

of

rhe

sometimes

energy used

efficiency. the

scream

required

engine

by

or

a

turbine

other

pumps

SYSTEM

in

turbine

is

reverse

osmosis Biphasr

stream

which

26”,

turbrnes to

This

pump

to

supplied paper

energy

Pelton still

be

by

the

the

Running”

limited

turbine,

pumps

LO about

85% of

the

approximately

are

70%

energy

70% of

from

the

energy

externalIy.

electric

high

usually

leaves

supplied

an

discusses to

are

drive, use

of

pressure

in

heat

the

pump,

combustion

internal

a waste

recovery,

seawater

hot

pump

and

the

plant.

consideratron

the

Biphasc

coupled

The

of

supply

under by

turbine

These

This

the

designed

“Reverse

pump-

these

DESIClU

manufactured

turbtne.

be

pressure but

power,

properly

pressure

turbine.

high

recovered.

either

to

the

the a

be

high

can

by

recover us;ng can

the

power

water

The

to

When

waste

This

required

AND IUWAJ

is

turbines

flashed

are and

will

approximately

is

turbrne

a

through consists

(660, from

1000

the to

“Biphase.

Systems first

an

device

presently

54”

vary

to

and/or

turbine

The

40”

drrectly system

LS a

Energy

pass

a

and

for

pressure

energy

from

1420

a

in

three

sizes

mm)-

The

LOO kilowatts a

34”

turbine"

Monrca,

California.

pump

the

turbine

a

nozzle

turbrne,

steam

approximately

kilowatts

Santa

converging-diverging a

conservation

heat

of

of

The

seawater

generator.

utrIizes

manufactured iOL6

high

electrrcal

that

of

waste

Company

separator

power for with

with

high to

srx

26”

a

single

and

from turbine

notzies.

hot

water

stage

a water

nominal

availabie a

pressure

wheel these wrth

turbine. diameters single two

nozzles

TIDBALL

The

AND

KADAJ

performance

waste

energy.

geothermal

of any This

wells,

Biphase

turbine

case

have

we

versus

oE shaft turbine

1500

power with

a 2500

kilowatt

Figure

shaft

is based

Low

pressure

size

used

turbine.

This

uould

be

seen

turbine

from

could

of a Biphase the

waste

system

300

from

the

turbine

suction

requirements

where

to an exhaust

exchanger

resulting

rn a flow

This

stream

35.2

bars

ing

stream

is then

and

liquid

expanded

a diesel

nozzle

The

of 2.2

kllograms through

In this

200

kilobdtts 26T

fitted

with

of shaft

kilowatts least

power.

of

1700

shaft

kilowatts

the

at

The

in velocity the

energy

and

balance

in the

L-59

emerges and

of the

to 0.359

from

the

returned

turbine

vapor

to the

Liquid

turbine to the

is shown

at 83.3OC booster

in Table

turbine

and

reverse in the

a diesel osmosis feed

engine. plant

water.

when The

This

48.3

28%

of the

velocity

the

second)

is

where

liquid Here

turbine.

to

enter-

from

per

0.559

bars.

is reduced

to a condenser

and

goes

gas,

bars.

it from

It is This

LS

pump. 1.

1 KW

78 75 67 -20 200 reverse system

instalLed SeaRO

and

is separated

of high

Separator Steam Turbine Liquid Turbine Pumps Net Output seawater

282OC

kilograms

passed

Power

a typical

at

and

the

water

then

exhaust

pressure

second

Item

3 shows

the

bars

raises

cooling

from

per

TABLE

Figure

diesel's

exchanger

the

(0.63

pump

for

Liquid-liquid

Approximately

vapor

separator

a

an

pressure

this

water

where

This

The

kilograms the

of hot

valve

nozzle.

the

from

exchanged

turbine.

separator.

through

concentrate

second

Biphase

turbine

steam

73.3oC.

are

a control

on the

to a vapor

kilowatts

through

from

effluent

This

pump.

first

energy

one-half

to a sufficient

circulating

The

per

pump

is passed

it

of thermal

passed nozzle

pressure

water.

1,486

where

is centrifuged

with

salts

200 of at

26T

kilowatts

Model

at approximately

by a booster

and

kilowatts

in a rotating

through

is condensed

from

high

circulating

is flashed

unflashed

reduced

to the

the

50 bars,

295

to the

water

is pumped

of

to approximately

exchanger

mixed

and

pressure

is transferred

day

heat.

when

kilowatts

generating

heat

the Model

shaft

a single that,

turbines,

is diesel

of generating

curve

produce

from

1700

require

this

gas

the waste

generating

a potential

avaiLable

desalting

power

to provide

engine

the

engines,

for

shaft

with

on using

condensate

absolute

pressure

the

diesel

of heat

on

power.

atmosphere

heat

stacks,

source

kilowatts)

same

balance

of course,

in available

engine

It can

the

furnace

on a diesel

Biphase

diesel,

2 is the heat This

power.

the

from

variation

diesel

nozzles.

is dependent,

interesting

selection

electrical

from three

come

most the

the

our

turbine

can

The

1 presents

based

(approximately

Biphase

energy

etc.

i'igure

engines.

the

139

system

osmosis was

sized

in the

plant

Arabian

contains

combined

to operate

two

Gulf

with

a 750 with

stages

a waste

cubic

42,000

in order

heat

meter

mg/l

sea

to reduce

per

140

141

I-

I I

f

TIDBALL

the

high

salinity

system

is

The

designed

process

ii

31.8

for

treatment

permeate

from the

to

to

the

first

of

than

500

mg/l

in

the

product.

This

recovery.

42,000

side

pJrped

to

stage

stage

less

product

suction

is

second

to

LS:

second

the

55 bars:

piped

water

28% overall

per

system (at

Gult

balance

energy

kiiograms

seawater

is

Z.rabian

AND XADAJ

of

the

oE

where

mgil, the

high

first

the

seawater

pressure

stage

SeaRO

8.85

3Z°C

of

plant

pumped The

pump.

the

is

kzlograms

is

reverse

second

at

high

a

plant,

the

to 28 bars 400

mg/L

pre-

pressure

osmosis

repressurized

per

through

and

potable

water

produced. 2)

22.9

piped

ki,

generating

the

94

Also

pump. the

grams

through

tallows: Power

recovery

operaL

Lorl.

Nocor

c-

for

operate

and d.

The

the is

per

cubic

are

high

required affcc:ed.

If

It of

for

shown load

f irsr

in

for (in

turbine

and

pouer.

Under

these

be

motor-generator,

pump

pumps

used

are

during

heat

is

other

during

purchased

out

of

pump

motor power,

service. durrng

available,

water

start-up.

rf the

with is

pressure

from be

Biphase

the

slzad

it

plant

excess

to

turbine

44.8

KWH

when

Table

both can

also

requirements

energy

generate

during

per

using

three. is reduced pump,

is

developed

saleable

periods

1000

a

plant

when

power the

water

S. gallons recovery

In this

case

the

second

the

total

287

stage

in

the

four

rrhe power of

normal

with

all

pumps

is

373

KW for

a

opermode

operating

rate

of

Ii.8

of water.

the power

pump

all

conditrons

--

turbine

kilowatts

power

under

pLant

cover Four

operating

demand

a power

from

day

requirements

recovery the

U.

per

instruments.

power

conditions

pumps

tl.1~ condition

These and

twot

meters

cubtc

II.

without

in column

seawater

i50

Lighting

shown

the

also

:he

column

Biphasc

Under

the

pressure

components

HOWever,

turbine high

power

could the

pressure

for

pressure

waste

is

servrce.

are

or

the

high

pressure

operation. could

for

clectrLcal

product

phase

meter

KW to

energy

requirements

the

it

stage

acmosphcrrc,

start-up.

hrgh

Biphase

sufficient

supply

turbine.

requirements

power

200

induction

high

to

power.

of

power

given, the

turbine stage

out

the

normal

first

the

These

the

during

the

driving

15 an

KW to

operation

supply

generate

entire

single

purchased

The

To

94

the

from

LS reduced

generator.

KW to

when

bars

in

shaft

available

during

49

pressure

assist

pump

94

pump

To

to

supply

used

piant

to

Biphase

from

are

full

operation..

-

To

supply

water

the

electric

LS not

be

and

conditions

without

KWH

the

saLeabLe

plant

the

To

not

generator

for

external

except azion

a

the

operating

-

power

-

Generator by

turbine

at

r+here

pressure

additional

turbine

start-up drtve

high

-

the

Biphase

horsepower

shaft

an

will

seawater

of the

generator

1s sizea to

reject turbine

This

motor

of

recovery

a?d

a.

Tnis

on

to

zurbine,

AS

b.

second

k:Lowatts

coupled

alphase

used

per power

and

without

demand

to

required

but

for

193 KU. the product

is reduced

the

the

The

Biphase

first

power

pump to 274

is not kilowatts

TIDBALL

AND

or a rate a power

this

four

pump

2500

last KU)

or

and

the

When

this

installed

the

stage

second

with

10.3

meter

Biphase

plant

high

on

the

stage

when

pressure

would

drive

fitted

be operated

shaft

pressure

1000

diesel

of operation,

high

2nd

Pump

Stage

Product

POWER

completely

large

to supply at

the

first

use.

Under

kilowatt

hours

per

enough,

the

pump

and

(approximately

to generate

heat

from

eiectrical the

power

other

300

the

diesel.

generator required

for

auxiliaries.

II - 750

CMD

SEAR0

PLANT

Biphase Turbine

Biphase Turbine

25 KU

25 KW

0

0 YW

0

57 KM

57 KW

57 Kw

0

iKw

4KW

4KW

0

36 KU

0

11.8

8.8

2.7

0

44.8

33.5

10.3

C

279

Kw

Annual Savings at $O.OS/KUH

KW

$144,000

$468,000

$496.800

28,438

85,173

117,196

5.06

- Yrs.

Annual Savings at $O.L/KWH

263,372

197,646 2-22

2.21

- Yrs.

2.35

5.49

65,276

Period

in

or other

nozzle

the waste that

Brphase Turbine

Additional Total Capital Cost $

Payback

sale

of 2.7

to generate

seawater

Kh'

373

Period

demand

193 KW

K!!H/CM

Payback

re.ults

No

287

8a_

on

'Ihe equipment

.IEQUIREHENTS

Pump

KWH/lOOO

turbine

the

for

were

it is imperative

of

Total

i(zJBiphase

an additional

25 Kw

Pump

This

gallons.

with

puar,, the

Pump

1st Stage

gallons.

reduces

a rate

engine

No

Seawater

a 200

for

Biphase %rbine Power Rectwery

Item

1000

available

TABLE EXTERNAL

per

This

required

per

if the

turbine

using

pump.

of power be

hours

that

UWH

25%.

7 kilowatts

could

mode

or 33.5

consumption

kilowatt

shows

the

kilowatts,

be

cubic

86 kilowatts

column

using

the

first

to zero

meter

The

per

of approximately shows

condition

cubic

KWH

savings

to the

stage

143

of 8.8

Column power

K9DIw

1.88

ECONOMICS The

economics

shown

on Table

al

costs-for

type

of

of producing II.

the

system

taken

from

shown

on Table

In each

fresh

Reference III.

750

cmd

of

the

energy

on current 2.

The

from

case

instaliation

based

water

cost

cost

of

of potable

studies. the

the

saving The

installed

sea

was

water

computed was

equipment cost system

of

for

produced. xere

the (Less

the

The

developed

Biphase diesel

four

cases

additionfor

turbine

each was

generator)

is

TID!3ALL

144

TABLE

R. 0.

Cost

in U.

Plant

Turbrnc

Turbine

100,000

System

225,000

L.,stal’atror.

75,000

Auxiliary

The with

annual column

20,OQO

Generator

Total

- 200

KW Output

Total

- 300

KW Output

savrngs 1 were

for

the

L,150,000 1,1'0,000

three

drcermined

as

systems

shown

Total

Cost

3. Profit

5_ Indirect 6. Total annual K!d saved The

for

94 x 0.05 x 0.85 0.95

x 8760

(at O.O5/KWH~ Pay The

the

are

shown

The shorter

method

on

Table

was

recovery = 86838 are

1070 of

1

100,000

225,000

10,000

22,500

of 4

the

turbine Dollars

7% of

the

10,000

22,500

120,QOO

270,000

24,000

54,000

144,000

324,000

formula:

x Hours/Year

that

tha:

generator

i44.000 86,838-(0.07 used

= Dollars

Per

Year

is: Per

Year

total

direct

x 120,000)

to calculate

at electrrcal

cost,

the

pay

back

period

costs

the

5.06

=

annual

of 0.05

Years

savings

and

0-L

and

dollars

the

pay

per

i(lJH. The

back

period results

II.

period

to use

shown

L

from

Factor

costs

=

cases

back

than

desirable

the

Period

three

pay

the N&O

5

is:

Back

above

for

add

calculated

energy

and

Biphase Turbine

Cost

was

the

that

LO'/.of

202

x $/hWH x Plant Elotor Efficiency

savings

Assuming

also

Capital

3,4

Power Recovery Turbine

Cost

Capital

savings

columns

Cost

Estrmate

2. G&?I

The

Capital

Source

Direct

II,

Iv

Additional

Item

4. Total

on Table

follows: TABLE

1. Direct

S. Dollars

750,000

Recovery

Brphase

KADAJ

III

Ccmponent

Energy

AND

for both

for

the

the

Biphase

systems

rf sufficient and

energy

rather waste

to generate

recovery

turbine than heat

power

turbine

(5.06

(5.87

years)

using

the

Biphase

is available, to operate

the

years)

indicating

is slightly that

turbine

alone.

it is economically entire

plant.

it is It is sound

to

TIDEALL

AND

KADAJ

145

SUMMARY Waste

heat

to convert on

the

waste

from

seawater

availability heat

and

the

industrial

process

to potable

of a constant salinity

of

can

water.

the

supply feed

be economically

The

feasibility

of waste

heat,

used of

with

reverse

the process

the

water.

REFERENCES 1) Biphase

Energy

Systems,

Report

DOE/ET/15350,

Topical

10-C

2) Biphase

Energy

Systems,

Report

DOEiETf15350,

Topical

10-B

temperature

osmosis

is dependent level

of

the