ion exchange resinslewatit.co.kr/main/tsg.pdf · 2011. 5. 24. · table of contents chapter 4 mixed...
TRANSCRIPT
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
Possible Cause SolutionReduced Throughput
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
Flow rates too high■ Insufficient reaction time - Reduce flow
(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”
Possible Cause SolutionReduced 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
restore capacity, double regenerate
- Adjust end point
Regenerant concentration - Check metering pumps,and quantity eductors, piping, etc.
- Regenerant dosage- 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 - Effluent flow control■ Flotation by dissolved gas - Top off■ Normal bead attrition
Resin age - Up to 5% / yr loss in capacityconsidered normal
- Analyze resin to determineremaining useful life
chapter 2
primary cationexchanger
5
6
Possible Cause SolutionReduced Throughput
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
Possible Cause SolutionPoor Effluent Quality
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 limit stops on valve operators
- Check air pressure on pneumaticvalves
- Check sealing gaskets onmultiports
- Check for physical damage due to water hammer
Flow rates too high■ Insufficient reaction time - Reduce flow
(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
Possible Cause SolutionPoor Effluent Quality
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
Resin fines - Remove with 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)
Valve partially closed - Check and adjust all valves
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
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”
Possible Cause SolutionReduced 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
restore capacity, double regenerate
- Adjust end point
Regenerant concentration - Check metering pumps,and quantity eductors, piping, etc.
- Regenerant dosage- Check dilution flows, time
settings- Apply correct amount at correct
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
Possible Cause SolutionReduced Throughput
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
Resin age - Up to 5% / yr loss in capacityconsidered normal
- 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
Possible Cause SolutionReduced Throughput
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
Possible Cause SolutionPoor Effluent Quality
Leaky valve - Check bed sample vs discharge pipe sample (before and after valving); special caution on backwash inlet valve
- Check limit stops on valve operators
- Check air pressure onpneumatic valves
- Check sealing gaskets onmultiports
- Check for physical damage due to water hammer
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” 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
Resin fines - Remove with 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)
Valve partially closed - Check and adjust all valves
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
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”
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
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