195830428 Brosur Resin Kation Dowex Hcrs Na

5/21/2018 195830428 Brosur Resin Kation Dowex Hcrs Na

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DowLiquid Separations

DOWEX HCR-SIon Exchange Resin

ENGINEERING INFORMATION


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DOWEX HCR-S Strong Acid Cation Exchange Resin

General Information

DOWEX* HCR-S strong acid cationexchange resin is produced by thesulfonation of a styrene divinyl-

benzene copolymer of controlledsize distribution.

The resin features a highcapacity with a porosity to assurean exemplary kinetic behavior. Itexhibits good physical, chemicaland thermal stability. These charac-teristics make it the resin of choicefor most water treatment applica-tions. DOWEX HCR-S resin is usedin softening as well as single ormixed bed demineralization.

* Trademark of The Dow Chemical Company

In addition to the standardgrade, DOWEX HCR-S MB (H) andDOWEX HCR-S PS are speciallygraded resins for use in mixed bed

and counter-current regenerationapplications respectively. DOWEXHCR-S D (H) is a dark colored resindesigned to give good opticalseparation when used in a mixedbed.

This brochure relates to waterdemineralization, using HCl orH

2SO

4as regenerants in co-current

or counter-current operations. Thepresented data allows the calcula-tion of operational capacities and

sodium leakages for different waterqualities at different temperaturesand levels of regeneration. Sepa-rate information is available on its

use in softening applications.DOWEX HCR-S resin is delivered ineither the sodium form or thehydrogen form.

In cases where physical stabilityis of major concern, premiumquality DOWEX HGR resin isavailable. This resin exhibits superi-or stability under stringent chemicalor physical conditions of operation.

Typical Physical and Chemical Properties

Ionic form as delivered Na+ H+

Total exchange capacity, min. eq/l 2.0 1.8

kgr/ft3as CaCO3 43.7 39.3

Water content % 44 - 48 50 - 56

Bead size distribution

range mm 0.3 - 1.2 0.3 - 1.2

>1.2 mm, max. % 5 5


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HydraulicCharacteristics

Backwash ExpansionUnder the upflow conditions ofback-washing, the resin will expandits volume (see Figure 1). Suchexpansion allows the regrading ofthe resin, fines removal and avoidschanneling during the subsequentservice cycle. At the same time,accumulated particulate contamina-tion is removed. An efficient back-wash will require an expansion ofover 50% of the original resinvolume and up to 80-100% expan-sion is common.

In co-current operation, the resinis backwashed for a few minutesbefore every regeneration. Occa-sionally, a longer backwash may beneeded to fully remove contami-nants.

In counter-current operation thestrainers are cleaned by the regen-erant flow. To retain the advantagesof counter-current operation it isessential not to disturb the resin.Backwashing is only desirable ifaccumulated debris causes an

excessive increase in pressure dropor to decompact the bed. Usually, abackwash is performed every 15 to30 cycles in conventional counter-current regeneration systems.

Pressure Drop Data

The pressure drop through a resinbed primarily depends on the beddepth and the flow velocity of thewater. It is further influenced by theparticle size distribution of the resinand by the viscosity, and thus

temperature, of the water. The datain Figure 2 shows the pressure dropper unit bed depth at various flowrates flow velocity for the standardgraded resin (0.3-1.2 mm). Anequation is also supplied which canbe used for temperature compensa-tion. These figures must be consid-ered representative only. The totalhead loss of a unit in operation will

Figure 1. Backwash expansion data

also depend on its design and issubstantially affected by the contri-

bution of the strainers surrounded byresin.

0

20

40

60

80

100

120

0 5 10 15 20 25 30

m/hLinear Flow Rate

0 2 4 6 8 10 12

H+ FormNa+ FormCa++ Form

gpm/ft2

PercentExpansion

m/hLinear Flow Rate

Form H+

Form Na+

Form Ca++

For other temperatures use:

FT= F

25C[1+0.008 (1.8T

C- 45)], where F = m/h

FT= F

77F[1+0.008 (T

F- 77)], where F = gpm/ft2

Temperature = 25C (77F)

Figure 2. Pressure drop data

For other temperatures use:

PT= P

20C/ (0.026T

C+0.48), where P = bar/m

PT= P

68F/ (0.014T

F+0.05), where P = psi/ft

gpm/ft2

Temperature = 25C (77F)

PercentExpansion

m/h

Linear Flow Rate

psi/ft


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OperatingCharacteristicsThe engineering design of an ion

exchange unit will depend on anumber of factors such as feedwater composition, desired capacityand water quality, and operationalconditions. The following informa-tion considers these factors andallows a design to be made.

The performance of the cationexchange resin will be evaluated onthe basis of the regenerationefficiency and the sodium leakage.Figure 3 indicates the contributionto conductivity due to sodiumleakage. This leakage is expressed

as NaOH as it appears in theeffluent of a strong base anionresin. When a weak base resinfollows the cation exchange unit,sodium will leak as NaCl and contri-bute to the conductivity accordingly.In this case, conductivity will alsobe due in part to CO

2, which should

also be taken into account.Sodium leakage will affect the

conductivity of the final effluent andalso influence the silica leakagefrom a strong base anion resin.

Data related to this influence ispresented in the engineering leaf-lets of the corresponding anion ex-change resins. Silica leakage andconductivity are the important featu-res of the final demineralized water.The correct design of the cationexchange unit will therefore have acritical impact on the overall per-formance and the ion exchangeplant.

When H2SO

4is used as regener-

ant, the permitted concentration ofH

2SO

4 is determined by the percent-

age of calcium in the feed water(see Figure 4). If the regenerant con-centration is too high or the regen-eration is performed too slowly, cal-cium sulfate will be deposited in theresin bed.

Step-wise regeneration may beused to improve the regenerationefficiency. As this applies especially

Figure 3. Na leakage expressed as conductivity at 25C (77F)after anion exchange

Figure 4. Permitted H2SO

4concentration


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Figure 7. Average Na leakage from DOWEX HCR-S resinin co-current operation with H

2SO

4as regenerant

to high regeneration levels, it may bemore attractive to use counter-current techniques in such cases.Concentrations of sulfuric acid

recommended for step-wise regen-eration are given in Figure 5. It iscommon to operate the first step atlow acid concentration and highflow rates. Operation in this fashionreduces the risk of calcium precipi-tation in the bed. It also makes itpractical to use a single speed acidpump. (The acid concentration iscontrolled by changing the volumeof dilution water used). At a presen-tation rate of 3 g H

2SO

4/min per liter

of resin at a concentration of 1%H

2

SO4

, this will amount to a regen-erant flow rate of 18 m3/h per m3ofresin (2.2 gpm/ft3).

Hydrochloric acid may be usedat concentrations of 4 to 8% irre-spective of the calcium content inthe feed water. High concentrationsof HCl and long regeneration timeswill be preferred when calcium andmagnesium predominate. Whensodium is the main constituent, HClat 4 to 5% will give the best efficien-cy.

Co-Current OperationFigures 6 and 7 show averagesodium leakage from DOWEX HCR-Sresin at different regeneration levelsusing HCl or H

2SO

4as regenerants.

These leakag es are expressed aspercentages of equivalent mineralacidity (EMA). Leakage levels will behigher at the beginning and towardsthe end of the service cycle. Whenvery high regeneration levels arerequired to obtain the desiredleakage, it is advisable to consider

counter-current operation. Data ontypical operational capacities forDOWEX HCR-S using HCl or H

2SO

4

are given in Figures 8 and 9.

Figure 5. Permitted H2SO

4concentration (step-wise)

Regeneration Level, lbs H2SO

4/ft3resin

2.5 5 7.5

Calcium % in feed water H2SO

4% permitted

Ca% < 15 H2SO4 3%15 < Ca% < 50 H

2SO

41.5% for 30%3% for 70%

50 < Ca% < 70 H2SO

41.5% for 50%3% for 50%

Ca% > 70 H2SO

41% or use HCl

AverageNaLeakage(as%

ofEMA)

Regeneration Level, kg H2SO4/m3resin

20

16

12

8

4

0

Figure 6. Average Na leakage from DOWEX HCR-S resin in co-current

operation with HCl as regenerant

2.5 5 7.5Regeneration Level, lbs HCI/ft3resin

AverageNaLeakage(as%

ofEMA)

Regeneration Level, kg HCI/m3resin


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Figure8.Co-currentop

erationalcapacitydata

Co-currentoperationa

l

capacity

data

(Step-wiseconcentration

inH

2SO

4

regeneration)

Instructions:

1.Locateapointontheordinateof

graphAfrom

percentsodium

and

percentalkalinity.

2.Transfertheordinatepointfrom

graphAhorizontallytographB

and

follow

theguidelineto

locateanew

pointontheordinateaccordingto

thepercentmagnesiu

m.


graphBhorizontallytographC

and

repeattheprocedure

underpoint2

accordingtochosenr

egeneration

1.5

1.4

1.0

0.6

1.2

0.8

level.Readoffthe

operationalca-

pacityontherighthandsideofthe

diagram

correspo

ndingtothisnew

ordinate.

160

140

120

100

80

60

50

k

gH

2SO

4/m

3

resin

10

8.75

7.5

6.25

5

3.75

3.1

lbsH

2SO

4/ft3resin

Regeneration

Level


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Figure9.Co-currentop

erationalcapacitydata

Co-currentoperationa

l

capacitydata

(HCIregeneration)

Instructions:


graphAfrom

percent

sodium

and

percentalkalinity.

2.Transfertheordin

atepointfrom

graphAhorizontallytographBand

follow

theguidelineto

thechosen

regenerationleve

lthusestablishing

anew

ordinate.

3.Readoffoper

ationalcapacityon

therighthandsideofthediagram

correspondingto

thisnew

ordinate.

1.9

1.3

1.7

1.5

1.1

0.9

0.7

30%

0%

120

100

80

60

40

kgHCl/m

3

resin

7.5

6.25

5

3.75

2.5

lbsHCl/ft

3

resin

Regeneration

Level


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Counter-Current Operation

The advantages of counter-currentoperation over co-current operationare well-known to be improved

chemical efficiency (better capacityusage and decreased regenerationwaste) and lower sodium leakage.Initial capital costs can be higher fora counter-current operation andmore care has to be taken in thedesign of a unit as it has to be ableto give the highest quality of treatedwater. Also, demineralized ordecationized water must be usedfor diluting the regeneration chemi-cals and for the displacement rinse.The design must ensure that the

chemicals contact the resin at thecorrect concentration by avoidingany excessive dilution. In conven-tional counter-current regeneration,a presentation rate of 2 gramregenerant per minute and per literresin has shown the best results foroptimum regeneration efficiency.This results in a regenerant flowrate 3 m3/h per m 3 (0.4 gpm/ft3) ofresin when a 4% regenerant con-centration is used.

Data on typical operationalcapacities for DOWEX HCR-S resin

using HCl or H2SO4are given inFigures 12 and 13. Levels of averagesodium leakage can be calculatedfrom data presented in Figures 10and 11. The desired leakage level isdivided by the alkalinity correctionfactor, which takes into account thealkalinity percentage of the influent.This corrected leakage valuetogether with the percentage Na inthe influent is now used to establishthe required regeneration level.

Conversely, the sodium leakage

for a given regeneration level canbe established by reading off avalue taking into account again thepercentage Na in the influent, andby multiplying this value with thealkalinity correction factor.

Figure 10. Average Na leakage for DOWEX HCR-S resin incounter-current operation and H

2SO

4as regenerant

(step-wise concentrations)

Figure 11. Average Na leakage for DOWEX HCR-S resin incounter-current operation and HCl as regenerant


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Figure12.Counter-currentoperationalcapacitydata

Counter-currentopera

tional

capacity

data

(H 2SO

4

regeneration)

Instructions:


graphAfrom

percentsodium

and

percentalkalinity.


graphAhorizontallytographB

and

follow

theguidelineto

thechosen

regenerationlevelthu

sestablishing

anew

ordinate.

3.Readoffoper

ationalcapacityon

therighthandsid

eofthediagram

correspondingto

thisnew

ordinate.

Important

Seecorrectiongrap

h

forresinbeddepth

ofless

than2meters.

Standardconditions:

BV/H

x

Salinity

(meq/l)=200

Temp.15

C

100

90

80

70

60

50

40

kgH

2SO

4/m

3

resin

6.25

5.6

5

4.4

3.75

3.1

2.5

lbsH

2SO

4/ft3resin

RegenerationLevel

InfluentWaterCo

mposition


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Figure13.Counter-currentoperationalcapacitydata

Counter-currentopera

tional

capacitydata

(HCIregeneration)

Instructions:


graphAfrom

percentsodium

and

percentalkalinity.



follow

theguidelineto

thechosen

regenerationlevelthu

sestablishing

anew

ordinate.

3.Readoffope

rationalcapacityon

therighthandsideofthediagram

correspondingto

thisnew

ordinate.

80

70

60

50

40

3

0

kgHCl/m

3

resin

5

4.4

3.7

5

3.1

2.5

1

.9

lbsHCl/ft

3

resin

Regeneration

Level


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The Bed Depth Effect

The geometry of an ion exchangeplant affects the capacity and thequality of the produced water. A bed

depth of about 1 m (3.3 ft) is ideal forco-current operation but little differ-ence exists going from 0.75 m to 2 mbed depth (30 to 6.5 ft). A flow velo-city of 20-30 m/h (8-12 gpm/ft2) maygive slightly better performancethan operating at 50-60 m/h (20-24gpm/ft2).

On the other hand, there is greatadvantage to gain from using a deepbed in counter-current operationwith sulfuric acid as regenerant.

The effect of bed depth is shown

in Figure 14.


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Figure14.Effectofbed

depth

3

4

6

7

5

(ft)

Effectofbed

depth

on

counter-currentcapacity

Instructions:

1.Locateapointonthe

ordinateof

graphAfrom

amountofE

MAand

chosenregenerationlevel.



follow

theguidelineto

locateanew

pointaccordingtothe

percent

sodium

ofEMA.


graphBhorizontallytographC

and

repeattheproce

dureunderpoint2

accordingtothe

desiredbeddepth

andreadoffthe

reductionincapacity.

gH

2SO

4/liter

%Capacity

EMA

%

Sodium

ofE

MA


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Dow EuropeDow Customer Information Group

Liquid SeparationsPrins Boudewijnlaan 41B-2650 EdegemBelgiumTel. +32 3 450 2240Tel. +800 3 694 6367

Fax +32 3 450 2815E-mail: [email protected]

Dow PacificDow Chemical Japan Ltd.Liquid SeparationsTennoz Central Tower2-24 Higashi Shinagawa 2-chome

Shinagawa-ku, Tokyo 140-8617JapanTel. +81 3 5460 2100Fax +81 3 5460 6246

Dow PacificDow Chemical Australia Ltd.

Liquid SeparationsLevel 520 Rodborough RoadFrenchs Forest, NSW 2086AustraliaTel. 61-2-9776-3226Fax 61-2-9776-3299

Dow Latin AmericaDow Quimica S.A.Liquid SeparationsRua Alexandre Dumas, 1671Sao Paulo SP BrazilCEP 04717-903

Tel. 55-11-5188 9277Fax 55-11-5188 9919

Dow North AmericaThe Dow Chemical Company

Liquid SeparationsCustomer Information GroupP.O. Box 1206Midland, MI 48641-1206USATel. 1-800-447-4369Fax (989) 832-1465

Internethttp://www.dowex.com

Toll-free telephone number for the following countries: Austria, Belgium,Denmark, Finland, France, Germany, Hungary, Ireland, Italy, The Netherlands,Norway, Portugal, Spain, Sweden, Switzerland, and the United Kingdom

Warning: Oxidizing agents such as nitric acid attack organic ion exchange resins under certain conditions. This could lead to anything from

slight resin degradation to a violent exothermic reaction (explosion). Before using strong oxidizing agents, consult sources knowledgeable in

handling such materials.

Notice: No freedom from any patent owned by Seller or others is to be inferred. Because use conditions and applicable laws may differ

from one location to another and may change with time, Customer is responsible for determining whether products and the information in thisdocument are appropriate for Customers use and for ensuring that Customers workplace and disposal practices are in compliance

with applicable laws and other governmental enactments. Seller assumes no obligation or liability for the information in this document. NO

WARRANTIES ARE GIVEN; ALL IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE ARE

EXPRESSLY EXCLUDED.

Published June 2002.

Dow Liquid Separations Offices.For more information call Dow Liquid Separations:

*Trademark of The Dow Chemical Company

Form No. 177-01694-602QRP

Documents

195830428 Brosur Resin Kation Dowex Hcrs Na