ION EXCHANGE RESINS - lewatit.co.kr · ION EXCHANGE RESINS ... table of contents Chapter 4 Mixed Bed Demineralizer ... a very effective method of troubleshooting an ion exchange resin

ION EXCHANGE RESINS

troubleshooting guide

ask yourself:

what has changed“”?

Chapter 1 Industrial Softeners . . . . . . . . . . . . .1

Chapter 2 Primary Cation Exchanger . . . . . . . .5

Chapter 3 Primary Anion Exchanger . . . . . . . .10

Chapter 4 Mixed Bed Demineralizer . . . . . . . .15

tabl

e of

con

tent

s

introduction

This guide has been assembled as a checklist of areas that can affect theperformance of the ion exchange process.

When the performance of an ion exchange resin bed has changed, it is a clearindication that at least one factor in the entire process has changed. Therefore,a very effective method of troubleshooting an ion exchange resin bed is to view thedemineralizer station or plant as being directly affected by several factors. Tosummarize, we can look at four areas:

1. What goes into the bed? This includes the feed stream, especially the current TDS, the backwash and rinse water, and the chemicals used forregeneration.

2. What is going on as far as what comes out of the bed? This includes instrumentation that measures pressure drops and both quality and quantityof effluent.

3. The mechanical aspects of the plant, which include pumps, valves, the vessel internals and fittings.

4. The ion exchange resin - its condition, age and the quantity in the vessel.

Possible Cause SolutionReduced Throughput

Increased ionic loading - Check influent water hardness- Increase regenerant- Add capacity

Channeling, poor distribution■ Suspended solids loading - Check backwash;■ Broken or clogged extend if needed

distributors - Repair■ Low flow - Maintain minimum flow

Premature break - Check previous run throughput- If normal regenerant does not

restore capacity, double regenerate

- Adjust end point

Regenerant concentration - Check metering pumps,and quantity eductors, piping, etc.

- Regenerant dosage - Do brine elution study (brine

curve)- Check dilution flows, time

settings- Apply correct amount at correct

concentrations

Resin loss■ Excessive backwash - Check temperature and flowrate■ Underdrain failure - Check and repair (resin trap?)■ De-crosslinked resin - See “oxidation”■ Flotation by dissolved gas - Effluent flow control■ Normal bead attrition - Top off

chapter 1

industrialsofteners

1

2


Resin age - Up to 5% / yr loss in capacityconsidered normal

- Analyze resin to determine remaining useful life

Resin oxidation ■ Presence of oxidants - Chemical pretreatment of

(chlorine) and oxygen feedwater/activated carbon in presence of catalysts filter(iron) causes - Replace resin when moisture de-crosslinking which content exceeds 65%reduces wet volume capacity(eventually high ∆P)

Resin fouling■ Iron, manganese, aluminum - Check water supply (analysis)

fouling and precipitates - Check backwash- Check regenerant chemicals

for contaminants (analysis)- Clean resin by air-scour and

backwash and chemically if required

■ Microbiological fouling - Clean resin with appropriate cleaner (compatible with resin)

Excessive rinsing - Check end-of-rinse set points- Readjust rinse time to suit- Check for fouling (see above)

Poor Effluent QualityNote: All of the items listed above for “Reduced Throughput” should

also be checked regarding poor effluent quality.

Leaky valve - Check bed sample vs. dischargepipe sample (before and aftervalving); special caution on backwash inlet valve

- Check limit stops on valve operators

- Check air pressure onpneumatic valves

- Check sealing gaskets on multiports

- Check for physical damage due to water hammer

3

Possible Cause SolutionPoor Effluent Quality

Flow rates too high■ Insufficient reaction time - Reduce flow

(kinetics)

Flow rates too low■ Poor distribution, channeling - Place one or more units in

standby to increase flowrate- Recycle treated water to inlet

Resin fouling - See “Resin fouling” above under “Reduced Throughput”

For counter-current regeneration: - Check resin level loss of inert (inactive) resin and add resin as needed allows resin migration which, inturn, causes high leakage

In counter-current regeneration, - Check resin level and add it is important to use soft resin as neededwater for regenerant dilutionand displacement rinse

High Pressure Drop

Bed compaction - Check flow and temperaturefor sufficient backwash

- Air or mechanical scourprior to backwash

Resin fines - Remove with backwash

Cation resin de-crosslink - Analyze resin and replace if necessary

Lower water temperature - ∆P increases with higher waterviscosity at lower temperature

Increased flow rate - ∆P increases with flow(do not exceed specified ∆P)

Valve partially closed - Check and adjust all valves

Internal distributor blockage■ With resin, iron, debris - Inspect strainers and clean

- Repair / clean distributors

4

Possible Cause SolutionHigh Pressure Drop


(kinetics)

Plugged underdrain■ Resin or subfill in collectors, - Inspect internals

outlet strainers

Increased suspended solids - Mid-cycle backwash loading in influent

Resin fouling - See “Resin fouling” above under“Reduced Throughput”

Low Pressure Drop

Note: Low pressure drop is not necessarily a problem in itself; however, it may be a symptom of a problem.

Leaky valve - Check bed sample vs. discharge

Reduced flow - ∆P decreases with flow

Increased temperature - Lower viscosity—checkbackwash rate at highertemperature

Resin loss, reduced bed depth■ Underdrain failure - Check for loss to sewer during

backwash and rinses ■ Resin attrition - Inspect and repair■ Resin loss - See “Resin loss” above under

“Reduced Throughput”


Increased ionic loading - Check influent water analysis- Increase regenerant- Add capacity

Channeling, poor distribution■ Suspended solids loading - Check backwash;■ Broken or clogged extend if needed

distributors - Repair■ Low flow - Maintain minimum flow

Premature break - Check previous run throughput- If normal regeneration does not


- Adjust end point


- Regenerant dosage- Check dilution flows, time


concentrations

Resin loss■ Excessive backwash - Check temperature and flowrate■ Underdrain failure - Check and repair (resin trap?)■ De-crosslinked resin - Effluent flow control■ Flotation by dissolved gas - Top off■ Normal bead attrition


- Analyze resin to determineremaining useful life

chapter 2

primary cationexchanger

5

6


Resin oxidation ■ Presence of oxidants - Chemical pretreatment of

(chlorine) and oxygen in feedwater/activated carbon filterpresence of iron (catalyst) - Replace resin when moisture causes de-crosslinking which content exceeds 65%reduces wet volume capacity(eventually high ∆P)

Resin fouling■ Calcium sulfate, iron, - Check water supply

manganese, aluminum - Check backwashfouling and precipitates - Check regenerant chemicals

for contaminants- Clean resin by air-scour and

backwash and chemically if required

■ Microbiological fouling - Clean resin with appropriate cleaner (compatible with resin)

Excessive rinsing - Check end-of-rinse set points- Readjust rinse time to suit- Check for fouling (see above)

Poor Effluent Quality

Note: All of the items listed above for “Reduced Throughput” shouldalso be checked regarding poor effluent quality.

Calcium sulfate precipitation■ Calcium in treated water - Check resin

should be zero - If severely fouled, replace resin - If moderately fouled, clean

resin with an HCl soak (caution—check materials of construction for compatibility with HCl)

- Check influent water calciumconcentration (% of total cations)

- Check and adjust acid concentration (stepwise regeneration) and flowrate

Presence of calcium phosphate or - Check pretreatment other complexes in feedwater

7


Notes: For weak acid cation exchangers regenerated with H2SO4,acid strength should not exceed 0.8 % with a flowrate of 2 gpm/ft3.

In countercurrent regeneration, it is important to use decationized or demineralized water for regenerantdilution and displacement rinse.

Once sulfuric acid injection is started, never stop flow. Ifacid injection must be interrupted, stop concentrated acid flow but let dilution flow run until all acid is displaced.

Excess sodium in treated - Check and adjust set points water ran past breakpoint - Check regenerant dosage

and quality- Investigate conversion to

upflow or hydrochloric acid regeneration

Leaky valve - Check bed sample vs discharge pipe sample (before and after valving); special caution on backwash inlet valve


- Check air pressure on pneumaticvalves

- Check sealing gaskets onmultiports



(kinetics)

Flow rates too low■ Poor distribution - Place one or more units in

channeling standby to increase flowrate- Recycle treated water to inlet

Resin fouling - See “Resin fouling” above under“Reduced Throughput”

8


For counter-current regeneration, - Check resin level at exhaustiona loss of inert (inactive) resin and add resin as needed allows resin migration which,in turn, causes high leakage

High Pressure Drop

Bed compaction - Check flow and temperature for sufficient backwash

- Air or mechanical scour priorto backwash


Cation resin de-crosslink - Analyze resin and replace if necessary

Lower water temperature - ∆P increases with higher viscosity at lower temperature

Increased flow rate - ∆P increases with flow(do not exceed specified ∆P)


Internal distributor blockage■ With resin, iron, debris - Inspect strainers and clean

- Repair / clean distributors

Plugged underdrain■ Resin or subfill in collectors - Inspect internals

or outlet strainers

Increased suspended solids - Mid-cycle backwash loading - Check filtration ahead of

demineralizer

Resin fouling - See “Resin fouling” above

9

Possible Cause SolutionLow Pressure Drop

NOTE: Low pressure drop is not necessarily a problem in itself; however, it may be a symptom of a problem.

Reduced flow - ∆P decreases with flow (normal)

Increased temperature - Lower viscosity- Check backwash rate at higher

temperature


backwash and rinses ■ Resin attrition - Inspect and repair■ Resin loss - See “Resin loss” above

under “Reduced Throughput”


Increased ionic loading - Check influent water analysis- Increase regenerant- Add capacity

Channeling, poor distribution■ Suspended solids - Check backwash,

loading extend if needed■ Broken or clogged - Repair

distributors■ Low flow - Maintain minimum flow

Premature break - Check previous run throughput- If normal regeneration does not


- Adjust end point


- Regenerant dosage- Check dilution flows, time


concentrations

If degasser (decarbonator) - Check CO2 at the outlet of theis used clearwell: should be less than

5 ppm. If not:- Check air filter on blower;

replace if dirty- Inspect packing (rings) in

column. If dirty or slimed, replace packing.

chapter 3

primary anionexchanger

10

11


Resin loss■ Excessive backwash - Check temperature and flowrate■ Underdrain failure - Check and repair (resin trap?)■ De-crosslinked resin - See “oxidation”■ Flotation by dissolved gas - Effluent flow control■ Normal bead attrition - Topoff


- Analyze resin to determine remaining useful life

Resin degradation■ Resin exposed to excessive - Do not exceed 120°F anytime

temperature for type I styrenic strong base anion resins

- Do not exceed 95°F anytimefor type II styrenic or type Iacrylic strong base anion resins

Excessive rinsing■ Organic fouling (organics - Partial restoration of resin

tend to hold on to sodium with a brine squeeze as they contain weak - Analyze resin for strong base sites which retain sodium) capacity and replace resin

if necessary - Incorporate routine brine

squeezes into operation of plant

- In the case of weak base anions,consider regeneration with ammonia

- Recycle rinse water to reduce water usage

- Adjust rinse end-point- Check caustic concentration

(higher concentration requires more rinse water)

- For high TOC waters, consider the installation of an organic trap

Presence of cation resin - Analyze resin in anion bed - Check for presence of cation

resin in anion bed- Identify cause of presence of

cation resin (leaky or brokenstrainer or lateral) and repair

12


Resin fouling■ Silica precipitation - Lower caustic strength (2.5%

suggested)- Thoroughfare regeneration

(strong base anion/weak base anion): dump first portion ofstrong base eluate before feeding residual caustic toWBA resin

If degasser (decarbonator) - Check air filter on blower; is used replace if dirty, damaged or

missing

Poor Effluent Quality

Note: All of the items listed above for “Reduced Throughput” shouldalso be checked regarding poor effluent quality.

High conductivity or pHin treated water■ Ran past cation breakpoint - Check cation effluent

- If cation effluent is withinacceptable range, check anionresin

Chemical precipitation■ Hardness in regenerant - Check for calcium and

dilution and / or rinse magnesium in cationwaters and anion effluent

- Insure that dilution and rinse waters are hardness-free

Hardness in treated water - Check cation performance- Check for hardness in all waters

used for regeneration to eliminate precipitates

Chloride or silica in treated - Check regenerant specs forwater chloride and silica content

(mercury cell or rayon gradesof caustic are acceptable)

- Check for leaking regenerant (caustic) valve

13


Leaky valve - Check bed sample vs discharge pipe sample (before and after valving); special caution on backwash inlet valve


- Check air pressure onpneumatic valves

- Check sealing gaskets onmultiports



(kinetics)

Flow rates too low■ Poor distribution channeling - Place one or more units in

standby to increase flowrate- Recycle treated water to inlet

Resin fouling - See “Resin fouling” aboveunder “Reduced Throughput”

For counter-current regeneration, - Check resin level at exhaustiona loss of inert (inactive) resin and add resin as neededallows resin migration which, inturn, causes high leakage

In counter-current regeneration,it is important to use demineralizedwater for caustic dilution anddisplacement rinse

High Pressure Drop

Bed compaction - Check flow and temperaturefor sufficient backwash

- Air or mechanical scour priorto backwash


Lower water temperature - ∆P increases with higher viscosity at lower temperature

14

Possible Cause SolutionHigh Pressure Drop

Increased flow rate - ∆P increases with flow (do notexceed specified ∆P)


Internal distributor blockage ■ With resin, iron, debris - Inspect strainers and clean

- Repair / clean distributors Plugged underdrain■ Resin or subfill in collectors or - Inspect internals

outlet strainers

Resin fouling - See “Resin fouling” aboveunder “Reduced Throughput”

Low Pressure Drop

NOTE: Low pressure drop is not necessarily a problem in itself;however, it may be a symptom of a problem.

Reduced flow - ∆P decreases with flow

Increased temperature - Lower viscosity- Check wash rate at higher

temperature


backwash and rinses■ Resin attrition - Inspect and repair■ Resin loss - See “Resin loss” above

under “Reduced Throughput”

Possible Cause SolutionReduced Throughput / Poor Effluent Quality

NOTE: Most comments for cation and anion apply to mixed-bed demineralizers and for best performance always usemixed-bed grade resin.

Poor primary exchanger - Troubleshoot primary cationperformance and anion exchangers

Poor separation of mixed bed in - Check flowrates and first step of regeneration temperature of backwash water

- Check for proper resinvs mid-collector interface location

- Insure use of mixed-bed grade resin

Interface too low because of - Add cation resin loss of cation resin

Interface too high because of - Check flowrates and separation and anion trapped temperature of backwash waterwithin cation bed - Correct flowrates

Interface too high because of - Remove appropriate overcharging of cation resin amount of cation resin

Cross contamination - Result of poor separation of the cation and anion resins; improper interface location dueto loss or overcharging of cationresin

Acid in the anion zone - Insure adequate which causes SO4 leakage blocking flow and early anion exhaustion

chapter 4

mixed beddemineralizer

15

Possible Cause SolutionReduced Throughput / Poor Effluent Quality

Caustic in the cation zone - Insure adequate which causes Na leakage blocking flowand early cation exhaustion

Insufficient displacement rinse - Extend displacementwhich results in resin cross- rinse to achievecontamination and high effluent acceptable conductivity conductivity

Insufficient mixing after - Check and adjust air flow regeneration step caused by insufficient air flow

Improper draindown prior to - Check water level prior to air air mix mix

- Adjust setting for water level

Fluidization and reseparation - Perform a slow fill of the bed during refill due to through the caustic distributor excess flowrate followed by a fast fill through

the service inlet

Excessive Final Rinse - Poor resin separation (see above)- Cross contamination (see above)

Premature silica break■ Silica precipitation due to - Start acid injection 20 minutes

contact with acid after start of caustic injection

16

A Bayer Company

100 Bayer Road

Pittsburgh, PA 15205-9741

Phone: 412 777-2000

200 Birmingham Road

Birmingham, NJ 08011

Phone: 609 893-1100

[email protected]

www.ionexchange.com

SYBRON CHEMICALS INC.

Design & Litho by Bayer Printing and Graphics Department/Pittsburgh

The conditions of your use and application of our products, technical assistance and information (whether verbal, written or by way ofproduction evaluations), including any suggested formulation and recommendations, are beyond our control. Therefore, it is imperative thatyou test our products, technical assistance and information to determine to your own satisfaction whether they are suitable for your intendeduses and applications. This application-specific analysis at least must include testing to determine suitability from a technical as well as health,safety, and environmental standpoint. Such testing has not necessarily been done by Bayer. All information is given without warranty orguarantee. It is expressly understood and agreed that customer assumes and hereby expressly releases Bayer from all liability, in tort,contract or otherwise, incurred in connection with the use of our products, technical assistance and information. Any statement orrecommendation not contained herein is unauthorized and shall not bind Bayer. Nothing herein shall be construed as a recommendationto use any product in conflict with patents covering any material or its use. No license is implied or in fact granted under the claims ofany patent. Bayer recommends the proper handling and disposal of wastes (pursuant to all applicable federal, state and local environmentaland safety laws, rules and regulations) from actions taken to correct a problem, and such corrective action should be consistent withany recommended maintenance requirements of the equipment manufacturer.

100 Bayer Road • Pittsburgh, PA 15205-9741 • Phone: 412 777-2000

Documents

ION EXCHANGE RESINS - lewatit.co.kr · ION EXCHANGE RESINS ... table of contents Chapter 4 Mixed Bed Demineralizer ... a very effective method of troubleshooting an ion exchange resin