Presented by

Charles AstburyCommercial Operations

GE Water & Process Technologies

Reducing Energy & Water In Your Boiler House

What areas can you impact?

• Reduce Blowdown– Saves water and energy

• Recover heat from Blowdown– Saves energy

• Recover Condensate– Saves water and energy

Cycles of Concentration

Cycles of Concentration

Cycles of Concentration

82

4=

Impact of blowdown on water

– At 10 cycles have 10% blowdown– At 20 cycles have 5% blowdown– At 50 cycles have 2% blowdown– At 100 cycles have 1% blowdown

Fuel

At 10 Cycles BD = 10.9T/HrCBD

IBD

BFW100 MT/Hr

2 MT/Hr

C=50

98 MT/Hr

2%

CBD

IBD

BFW100 MT/Hr

2 MT/Hr

C=50

98 MT/Hr

2%

Impact of blowdown on efficiency

Cycles % BD FW BDWith No Heat

RecoveryWith Flash Tank

Bottoms

With Flash Tank and Heat Exch

klb/hr klb/hr10 10% 111,111 11,111 $367,531 $147,947 $11,83620 5% 105,263 5,263 $174,093 $70,080 $5,60650 2% 102,041 2,041 $67,506 $27,174 $2,174

BasisSteam 100,000 lb/hrPressure 600 psi

BD Heat Lost, $/yrBTU Value of Blowdown Heat

50 cycles versus 10

cycles saves $300,000/yr

50 cycles versus 10

cycles saves $120,000/yr

50 cycles versus 10

cycles saves $10,000/yr

How do you reduce blowdown?

Turn it down........– Increase deposition risk

– High performance chemicals– Decline in steam purity

– Steam purity is a direct function of boiler water dissolved solids content

Improve makeup water quality

Discussion Topics

BFW & steam purity requirements

Pretreatment Methods

Membrane solutions for boiler– RO in front of demineralizers– RO replacement of softeners

Begin the feedwater system design process by defining your end state water quality needs

What level of water purity do the boiler and steam processes require?

ASME GUIDELINESTable 1 - Watertube Boiler with Superheater/Turbine

All Pressures: FW dissolved oxygen < 7 ppb (with DA)Feedwater pH: 8.3 - 10.0 (0- 900 psig) / pH 8.8 - 9.6 (> 901 psig)

0 to 300300 to 450451 to 600601 to 750751 to 900901 to 1,0001,001 to 1,5001,501 to 2,000

DrumPressure

(psig)Iron

(ppm Fe)

0.1000.0500.0300.0250.0200.0200.0100.010

Copper(ppm Cu)

0.0500.0250.0200.0200.0150.0150.0100.010

TotalHardness

ppm CaCO

0.3000.3000.2000.2000.1000.0500.0000.000

SilicappmSiO

15090403020821

Totalalkalinity

ppm CaCO

350300250200150100

--

SpecificConductance µmhos/cm)

(Unneutralized)

350030002500200015001000150100

Boiler Feedwater Boiler Water

3 2 3( ))( ( ) (

Note: All limits are expressed “less than” the value specified (e.g., < 0.100 ppm)

GE Steam Purity Recommendations for Utility Steam Turbines with Reheat Steam

Parameter All Volatile Treatment

Phosphate Treatment

Equilibrium Phosphate Treatment

Sodium, ppb <3 <5 <3 Cation Conductivity, uS/cm

<0.15 <0.3 <0.15

Silica, ppb <10 <10 <10

Chloride, ppb <3 <3 <3 Sulfate, ppb <3 <3 <3 Total organic carbon, ppb

<100 <100 <100

* “ Steam Purity Recommendations for Utility Steam Turbines”, GEK 72281A, July, 1996

BFW quality considerations

• Boiler pressure and superheater/turbine steam purity requirements generally define pretreatment and feedwater quality requirements.

• In general:– Softened or single pass RO < 600 psig– Demineralized or RO/EDI > 900 psi

RO – Reverse OsmosisEDI - Electrodeionization

Technologies to Improve Makeup Water Purity

Softeners

Dealkalizers

Demineralizers

Reverse Osmosis Systems

Resin Based Pretreatment Performance

Softener 0.2-1.0 ppm hardness (no TDS reduction)

0 to 600

Dealkalizer 50 to 90% alkalinity reduction (no TDS reduction)

0 to 600

Standard two-bed demineralizer

<10 µmho <200 ppb silica

400 to 900

Two-bed demineralizer with counterflow regeneration

<5 µmho <50 ppb silica

900 to 1,200

Two-bed demineralizer with mixed bed polisher

<0.1 µmho <10 ppb silica

1,200+

System Typical EffluentQuality

Typical BoilerOperating

Pressure (psig)

Zeolite Softening & Dealkalization

AdvantagesInexpensive – Cap & Op costs

Simple-to-operate

Durable

Safe & inexpensive sodium chloride regenerant

LimitationsNo reduction in TDS

FW quality can limit boiler cycles

Not suitable for high-pressure boiler operation (> 900 psig)

No silica reduction

No alkalinity reduction without dealkalizer

Resin-based demineralization

Advantages

Reduction in all dissolved solids

Enables high cycles operation

Suitable for high-pressure boilers

Can tailor to specific purity needs

Excellent silica rejection

Excellent alkalinity/CO2 rejection

Limitations

Strong acid/caustic required for regeneration

Caustic costs high & variable

Limited anion resin life

Silica and sodium leakage

Manpower intensive

Operating costs directly proportional to TDS

Reverse OsmosisAdvantages

Rejection of all dissolved solids

Operating costs not directly dependant on TDS

Enables high cycle boiler operation

Requires no chemical regenerants (acid/caustic)

Not labor intensive

Versatile pairings with resin-based systems

Ideal for mobile applications

LimitationsRO alone not suitable for HP boiler feedwater > 1000 psig with turbine

Higher electrical costs than resin-based systems (high-pressure pumps)

Generates significant reject stream(typically 20 – 30% of input stream)

Does not reject CO2 (g)

What are the tools available?

• CCR Bankbook• Feedwater Economic Models• BoilerCalc• Condensate Modeling System

What are the tools available?

• CCR Bankbook• Feedwater Economic Models• BoilerCalc• Condensate Modeling System

Touch on this

Focus on this

CCR Bankbook

Potential Membrane Solutions for Boiler Systems1. RO in front of existing demineralizers

2. RO in front of, or to replace existing softeners

3. New plant—RO/MB or Demin/MB?

4. 2 pass RO/EDI to replace resin-based demineralizer- Mixed-bed quality train

5. Ultrafiltration in front of demin. or RO to replace traditional filtration/clarification

RO ahead of Existing Demin

•Reduced acid & caustic regenerant costs– 90 – 95% reduction in regenerant usage is typical

•10 to 15% more feedwater production each month

•90% less (high TDS) regenerant waste

•Extended ion exchange resin life– 40 – 50% extension in resin life typical– Much longer regen. cycles & reduced iron/organic fouling

•Improved feedwater & steam quality– Sodium & silica slippage & breaks reduced

Detailed economic & environmental benefit analysis and modeling is required

Key input variables for modeling & analysis

TDS of influent water

Capital equipment costs

Caustic and acid costs

Electrical power rates

Influent water costs

Sewer costso Volume or Vol/TDS-basis?o Can plant reuse RO reject?o Credits or incentives for reuse

Regenerant neutralization costsDifferential labor costs

Reduction of acid/caustic inventory

Safety - chemical exposure

Water scarcity issues

Discharge/permitting issues

Economic Environmental

RO preceding DemineralizerApproximate TDS Breakeven

360500$2.00$1.50

310470$2.00$.50

275405$1.00$.50

230380$.50$.50

Flow, 450 gpm

Flow,

50 gpm

Waste Water, $/kgal

Raw Water, $/kgal

Presented by

Economic Models

Two New powerful tools for quick evaluationproviding value to our customers

Data input section

Result output section

Soft saving section

Saving Water & Energyis a Big Win in Every Way,

and the creative use of Membrane solutions for Boilers can help you to make it happen at your

facility! These are just two of the many possibilities …

Thank you for your time & attention