Boiler Water System Protection Ppt Puckorius201012

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Welcome

EFFECTIVE BOILER WATER

SYSTEM PROTECTION

Presented by

Paul R. Puckorius

Puckorius & Associates, Inc

December 7, 2010

Presented by Process Heating

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EFFECTIVE BOILER WATER

SYSTEM PROTECTION

Presented by

Paul R. Puckorius

Puckorius & Associates, Inc

December 7, 2010

Presented by Process Heating

THIS WEBINAR WILL

COVER THESE TOPICS

LOW PRESSURE BOILERS- < 900 psi

WHAT WATER QUALITY IS NEEDED

HOW TO PROTECT THE BOILER

WHAT TREATMENTS WORK WELL

WHAT CONTROLS ARE IMPORTANT

HOW TO PROTECT YOUR

BOILER

Feed it Good Quality Water

Maintain Good Water Treatment Control

Handle Varying Steam Demand

Handle Startup and Shut Down Properly

Protect Boiler When it is Layed Up

Objectives of Boiler Water

Treatment Program To Prevent Deposits on Boiler Tubes

To Prevent Corrosion of all Metals in Entire Boiler Cycle

To Produce Good Steam Quality for all Uses at all Times

To Prevent Boiler Tube Failures

To Properly Startup, Shut Down, & Layup Boilers

An Effective Boiler Water

Treatment Program Prevent Deposits on Boiler Surfaces

(causes loss of heat transfer & weakens

metal due to over heating)

Prevent Oxygen Corrosion (causes

pitting of boiler tubes & rust deposits)

Prevent low pH (below 9 will cause

corrosion and produce red water)

Prevent condensate contamination (may

result in iron, copper, & oil into boiler)

Produce Acceptable Steam Quality

WHAT IS GOOD QUALITY

WATER?

Provides Efficient Equipment Operation

Increases Life Expectancy & ROI

Optimizes Water Use and Waste

Cost Effective Programs

Reduces Maintenance and Labor

GOOD QUALITY WATER

DEPENDS UPON

Boiler Pressure

Boiler Operation

Boiler Design

Consistent & Effective Makeup Water

ASME Boiler WaterGuidelinesNo Superheaters & Turbines

Steam Purity 1 ppm Maximum

0-300 psig 301-600 psig

SiO2 <150 <90

T. Alkalinity; ppm <1000 <850

OH Alkalinity; ppm NS NS

Mmho <7000 <5500

ASME Boiler Water GuidelinesFiretube Boilers

1 ppm TDS Maximum Steam Purity

0 to 300 psig

SiO2; ppm <150

T. Alkalinity; ppm <700

OH Alkalinity; ppm NS

Mmho <7000

ASME Boiler Water GuidelinesWatertube Boilers

With Super heaters/ Turbines

SiO2 Total Alk. OH Alk. Mmho

0-300 <150 <350 NS 5400-1100

301-450 <90 <300 NS 4600-900

451-600 <40 <250 NS 3800-800

601-750 <30 <200 NS 1500-300

751-900 <20 <150 NS 1200-200

901-1000 <8 <100 NS 1000-200

1001-1500 <2 NS NS <150

1501-2000 <1 NS NS <80

ABMA Boiler Water Limits

BW TDS Steam TDS TSS FCO

0-300 psig 3500 1.0 15 0.0003

301-450 psig 3000 1.0 10 0.0003

451-600 psig 2500 1.0 8 0/0004

601-750 psig 1000 0.5 3 0.0005

751-900 psig 750 0.5 2 0.0006

901-1000 psig 625 0.5 1 0.0007

1001-1800 psig 100 0.1 1 0.001

1801-2350 psig 50 0.1 1 0.002

2351-2600 psig 25 0.05 1 0.002

2601-2900 psig 15 0.05 1 0.003

TYPICAL BOILER SYSTEM

Boiler

Steam

Uses

Deaerator

Makeup

System

SteamCondensate Makeup

Boiler

Feedwater

Boiler

Feedwater Pump

Losses

Losses

Blowdown

FIRE TUBE BOILER

Firetube Boilers

Heat on Inside of Tubes

Water on Outside of Tubes

Advantages

– Suitable for low pressure operation

– Reliable

– Low Space Requirements

Firetube Boilers

Disadvantages

– Limited pressure; ~300 psig

– Relatively poor steam quality; small

steam release space

WATER TUBE BOILER-TYPE D

Watertube Boilers

Water on Inside of Tubes

Heat in Furnace Surrounding Tubes

Various Types/Designs

– “A” Type

– “O” Type

– “D” Type

– “L” Type

“Unlimited” Pressure

Good Steam Quality

Watertube Boilers

+ Advantages –

-Suitable for High Pressures

-Reliable

-Excellent Steam Quality

+Disadvantages

-Large Space Required

-Requires Very Good Water Quality

-Sensitive to Deposits/Corrosion

PROTECTING BOILER

FROM CORROSION

Boilers are Made of Carbon Steel

Must Form a Protective Coating

Coating is a Form of Iron Oxide

Coating is Called Magnetite

Coating is Black and Hard and Thin

HOW TO FORM MAGNETITE

Remove Oxygen to Zero in Boiler

Raise pH of Boiler Water above 10

Prevent all Deposits on Boiler Surface

Carry a High Hydrate Alkalinity in Boiler

MAGNETITE- WELL PROTECTED BOILER TUBES

DEPOSIT CONTROL

METHODS

Remove Before Boiler- Known as

External Treatment of Makeup Water

Condition Potential Water Deposits in

the Boiler- Known as Internal treatment

of Boiler Water

BOILER WATER DEPOSIT

CONTROL – EXTERNAL

VERY COMMON Sodium Zeolite Softening- removes only

the hardness

Cold /Hot Lime Softening- removes

hardness, some alkalinity, and some

dissolved solids

Demineralizers- removes Everything

Reverse Osmosis- removes Everything

BOILER DEPOSIT CONTROL–

INTERNAL METHOD-

KEEPING DEPOSITS SOLUBLE

Specialty Chemicals such as

Phosphonates, and Polymers- Very

Common in Boilers Operating at <600 psi

Previous Chemicals used were Chelants

such as EDTA and NTA- Not very common

currently due to Corrosion Concerns

BOILER DEPOSIT CONTROL–

INTERNAL METHOD-

KEEPING DEPOSITS SOLUBLE

Often requires low hardness Feed Water

+ Usually less that 2 ppm hardness needed

+ If higher Hardness, Costs for WT higher

Produces a much Cleaner Boiler

+ Due to Solubilized Hardness- no Sludge

+ Maximizes Boiler Heat Transfer

BOILER DEPOSIT CONTROL–

INTERNAL METHOD-

FORMING DEPOSITS (SLUDGE)

Most Common- add Phosphate to Boiler

+ Will form hardness “sludge”

+ Will be removed by Blowdown

Use of Phosphate w/Polymer/Phosphonate

+ Will form some soluble and some “sludge”

+ Will provide a “cleaner” Boiler

Sludge Conditioners & Dispersants

Sludge conditioners allowed sludge to

remain free flowing and accumulate in

bottom drum

Current approaches

– Low feedwater hardness

– Keep precipitated particles dispersed so

they can be removed with surface

blowdown

Naturally Occurring Sludge Conditioners and Dispersants

Tannins

Lignins

Starch

Seaweed derivatives

Sugars

Carboxymethyl cellulose

BOILER DEPOSIT CONTROL–

INTERNAL METHOD-

FORMING DEPOSITS (SLUDGE)

Phosphate Levels 20-40ppm in Boiler

+ Ortho Phosphate can cause deposits in

feed water line

+ Poly Phosphate will not cause deposits in

feed water line

Polymers/ Phosphonates Levels often 10-

30ppm in Boiler

Summary of Phosphate Treatment Programs

PO4 OH- Na:PO4 Ratio pH

Conventional 20-40 100-350 N/A 11 - 12

Coordinated 5-25 Trace 2.85:1 to 3:1 (9 - 10.5)

Congruent 2-5 Zero 2.3:1 to 2.6:1 (8.8 - 9.4)

Equilibrium <2.4 <1.0 N/A (9.3 - 9.6)

Phosphate ProgramsAlternatives Based on Pressure

PSIG 0-300 301-450 450-600 450-600 601-750 751-900

PO4; ppm 30-60 30-60 20-40 5-25 <2.4 <2.4

Mmho 1100-5400 900-4600 800-3800 200-800 <150 <150

TDS; ppm 550-2700 450-2300 400-1900 100-400 <75 <75

OH Alk;

ppm

20-200 6-50 2-20 1-4 0.17-1.0 .17-1.0

pH 11-12 10.5-11.5 10-11 9.7-10.4 9.0-9.7 9.0-9.7

SO3; ppm 20-40 20-40 15-30 10-20 5-10 3-8

SiO2; ppm <150 <90 <40 <8 <2 <2

Polymer 5-10 5-10 3-8 2-5 2-5 1-3

Makeup Soft Soft Soft DI DI DI

BOILER DEPOSIT CAUSES

Loss in Heat Transfer- Wasted Fuel

Possible Gradual Boiler Tube Softening

and Eventual Failure

Corrosion Under Deposits due to

Caustic Concentration

Effect of Overheating Due to Deposits

Long-term Overheating Tube Failure

OXYGEN REMOVAL

METHODS

Mechanical Deareation of Feed Water

+ Various Types Of Equipment using

Heat and Steam

Chemical Oxygen Scavengers

+ Various Types Of Chemicals

Oxygen Pitting

DEAREATOR OPERATION

Maintain Adequate Temperature- This is

at Full Saturation for the Pressure

Maintain Good Agitation- This is to

Obtain Steam & Water Mixing to Strip

Gases from Water

Maintain Proper Steam Plume for

Proper Partial Pressure of Atmosphere

Principles of Deaeration

Heating

Agitation

Adequate Venting

Practical Considerations

90 - 95% of oxygen is removed easily by mechanical separation; the remaining 5 -10% must be removed by molecular diffusion.

Types of O2 Scavengers

Non-Volatile Oxygen Scavengers– Stay in boiler water

» Sodium sulfite most common

» Erythorbic acid (iso ascorbic acid-vitamin C)

» Sodium erythorbate

» Amine neutralized-proprietary

Volatile Oxygen Scavengers– Exit boiler with steam

– Hydrazine most common; also other “hydrazine substitutes”

OXYGEN SCAVENGERS

Sulfite is most Common

Often Sodium Sulfite with Catalyst (Co)

and is a Dry Product

Recently Sodium Bisulfite which is

much more Soluble and thus a liquid but

it is acid and needs more alkali

Common Dosage is 20-40 ppm Sulfite

Volatile Oxygen Scavengers

Hydrazine

Diethylhydroxylamine - DEHA

Carbohydrazide

Hydroquinone

Methylethylketoxime - MEKO

CONDENSATE SYSTEM

CORROSION CONTROL

Need to Prevent Low pH due to Carbon

dioxide

Need to be sure Oxygen is not Present

since will Cause Pitting Corrosion

Carbon Dioxide Gouging

CONDENSATE SYSTEM LOW PH

CORROSION CONTROL Need to Neutralize the Carbonic acid

(carbon dioxide dissolved in water)

Consider using a Dealkalizer if very high

Carbon Dioxide

Use Organic Chemicals known as

Neutralizing Amines

Neutralizing Amine will not protect against

Oxygen corrosion

Dealkalization of Boiler Feedwater

Purpose of alkalinity reduction– Bicarbonates in makeup water decompose in

boiler to produce carbon dioxide

2NaHCO3 + Heat Na2CO3 + CO2 + H2O

Carbon dioxide is carried with steam

– CO2 combines with water to form carbonic acid. Low pH condensate causes acid corrosion of condensate piping

CO2 + H2O H2CO3

H2CO3 H+ + HCO3-

CONDENSATE SYSTEM-

NEUTRALIZING AMINES +Most common are these three amines

+Morpholine/ Cyclohexylamine/ and

Diethylaminoethanol (DEAE)

+Amines are added to the Boiler and the

Steam carries into the Condensate

+These three can be used alone or often

blended to give better system protection-

they condense throughout entire system

DISTRIBUTION RATIO

DEFINED AS THE RATIO OF AMINE REMAINING IN STEAM TO AMINE IN CONDENSATE

AMINE WITH HIGH DISTRIBUTION RATIO STAYS IN STEAM LONGER

AMINE WITH LOW DISTRIBUTION RATIO CONDENSES WITH “EARLY” CONDENSATE

DISTRIBUTION RATIOS OF COMMON AMINES

AMINE DISTRIBUTION RATIO

MORPHOLINE 0.48

CYCLOHEXYLAMINE 2.6

DEAE 1.45

AMP 0.31

AMMONIA 10

METHOXYPROPYLAMINE 1.0

CONDENSATE CORROSION

CONTROL FROM OXYGEN

Need to Prevent any Oxygen Entering

System by stopping any in leakage

If Oxygen continues entering the steam and

in the condensate- Need to use a Filming

Amine to “coat” the condensate pipe

CONDENSATE CORROSION

CONTROL FROM OXYGEN

Filming Amines used are –

+Octadecylamine (ODA)

Filming Amines must be added to the

Steam line- not the boiler

Filming Amines difficult to control dosage

Often both Neutralizing & Filming Amines

are blended together to help each

STEAM QUALITY NEEDS

Need to Identify Steam Uses

If only Heating-Not as critical

If to drive Turbines- Need low Silica in

Boiler Water and No Carryover

If both Heating and Turbines- Need Low

Silica in Boiler Water and No Carryover

BOILER WATER MONITORING Advanced Method-Traces Active Treatment

Automatic Steam Quality & Purity Testing

Continous Conductivity Tests/Blowdown

Numerous Condensate Corrosion Testing

Monitoring “Transport’ of Iron

Automatic Monitoring reduces time for

Manual Testing & Improves Accuracy

Also Phosphate/pH/turbidity, etc

NEW BOILER STARTUP

Need to Implement an Alkaline “Boilout”

Will remove Oil/ Grease/Rust to prevent

Deposits and Over Heating of Tubes

Acid Needed if Much Mill Scale on Tubes

If Acid used, Follow with an Alkaline Boilout

Use of Neutral pH Boilout Treatment may

not be as efficient as Alkaline Boilout

BOILER LAYUP METHODS

Wet Layup needs “full” Boiler, hi pH. Sulfite

Dry Layup needs no moisture and nitrogen

Volatile Vapor Phase Inhibitors used for

both Wet and Dry Layup

TREAT YOUR BOILER WELL

Will Provide Long Life & Good Operation

Will Prevent Poor Quality Steam

Will Save Considerable Energy

Will Reduce Maintenance & Repair

Will Save Manpower Time

You Will Sleep Well

Good Luck with Your Boiler

WHO IS PUCKORIUS & ASSOCIATES, INC?

PROVIDE CONSULTING SERVICES ONLY

DO NOT SELL CHEMICALS OR EQUIPMENT

WORK THROUGHOUT THE WORLD

WORK ON ALL TYPES OF WATER SYSTEMS

PROVIDE TROUBLE SHOOTING, PREPARATION

OF SPECIFICATIONS, TRAINING AND LITIGATION

PROVIDE EVALUATION OF WATER TREATMENT

PROGRAMS AND COST EFFECTIVE

APPLICATIONS

SAVE OUR CLIENTS MANY TIMES OUR FEES

NEED MORE HELP?HOW TO CONTACT US?

Puckorius & Associates, Inc. 6621 West 56th Ave

Suite 200 Arvada, Colorado 80002

Phone-303-674-9897 Fax-303-674-1453

Florida Office- 9005 Lake Lynn Drive Sebring, FL 33876

Phone 863-655-1036

E-mail Waterphd1@aol.com

Web - www.Puckorius.com &

www.watertrainingservices.com

Paul Puckorius cell- 303-638-0587

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