Novel Terpolymer Technology for Scale Prevention in Steam

Imagination at work.

Anthony M. Rossi Global Boiler Product Manager GE Water & Process Technologies

Novel Terpolymer Technology for

Scale Prevention in Steam Boilers

2 GE Title or job number

3/5/2014

Why is effective control of

excessive Boiler scale

formation important to you?

Fuel costs – Maintaining design efficiency

Reliability – Avoiding tube failures & unscheduled outages

Controlling maintenance, repair & cleaning costs

Typical Boiler Plant Cost Factors

Fuel 75% Labor 9.5%

Equip.

Depreciation

9.5% Electricity

2.5%

Sewer 1.2%

Water 0.8%

Water Treatment Chemicals 1.5%

5 / GE /

Potential efficiency loss due to waterside scale

6 / GE /

Additional implications of excessive waterside scale deposits

Not just reduced efficiency, but …

Tube failures due to – o Long-term overheating

o Poor circulation leading to starvation – overheat

o Under deposit acidic or caustic corrosion

Thermal conductivity of common waterside scale deposits versus boiler steel

Thermal Conductivity

(BTU/hr per ft2 per F per inch)

Boiler Steel 310

______________________________________________

Calcium phosphate 25

Iron oxide 20

Calcium carbonate 16

Magnesium phosphate 15

Typical silicate scale <1

> 850 F

600 F o

500 F o 500 F o

Metal Wall

Tube

Metal Wall Tube

Waterside Waterside Fireside Fireside

Scale

BOILER TUBE HEAT TRANSFER

o

Design Temperature

Profile

Temperature Profile

With Scale

600 psig Boiler Overheating tube failure due to Water side scale

9

Water wall tube from a 400 psig Boiler receiving RO make-up Example of metal oxide deposit-induced overheating & under

deposit corrosion

Heavy metal oxide-dominated deposit resulted in

overheating rupture that was associated with tube

thinning due to severe under deposit corrosion

11 / GE /

Maintaining clean waterside surfaces Critical elements

1. Effective Pretreatment Removal or reduction of scale-forming ions

2. Effective cycles & dissolved/suspended solids control

Automated blowdown control

3. Effective chemical treatment

12 / GE /

Three Key Polymer Deposit Control Mechanisms

1. Dispersion - prevents particle attachment to surfaces & to each other

2. Crystal Modification - retards particle growth & size

3. Complexation – keeps scaling hardness cations – calcium & magnesium - in solution

Calcium Phosphate - Magnesium Silicate

mixed hardness deposit Untreated Condition – 4000X

Untreated condition

4000x photo

Note that the individual deposit crystals have coalesced Into a large agglomerated mass. This large particle is difficult to maintain in the boiler water and remove with blowdown.

Same hardness contaminant matrix and boiler conditions as previous slide

except for addition of an effective polymeric dispersant

Treated with carboxylated polymer

With an effective polymeric dispersant, the hardness deposit is maintained as a population of small, easily dispersed particles which are colloidal and can be removed via blowdown.

4000x photo

15 / GE /

First Generation Polymer Chemistries

CH2 C

C

O-

n

Polyacrylate

H

Polyacrylamide Polymethacrylate

O

CH2 C

C

NH2 n

H

O

CH2 C

C

O-

n

CH3

O

PMA PAA PAAM

Solus AP Boiler Terpolymer (BTP) • Patented terpolymer technology

- Acrylic acid plus two unique monomers

• Two unique sulfonated monomers enhance performance on iron, magnesium & silica

• Derived from highly successful previous generation patented GE boiler copolymer technology

Dual Sulfonated Functional groups

x

Wide spectrum deposit control performance

Deposition Rate at Heat Transfer Surface

with Solus AP versus Untreated Control

Solus AP boiler internal treatment is designed to maintain clean, essentially scale-free & efficient boiler heat transfer surfaces, even under upset and stressed conditions

Actual GE Research Boiler Test Heat Transfer Surface Comparison at 300 psig

Impact of Solus AP Treatment

Untreated control at 300 psig in hardness-dominated feedwater

Solus AP treatment at 300 psig under identical test conditions in hardness-dominated feedwater

Enhanced Transport of Iron, Magnesium, and Silica

Contaminants thru the Boiler

Reduced sludge accumulation

Reduced sludge accumulation

0

10

20

30

40

50

60

70

80

90

100

150 300 600

% F

ee

dw

ate

r Ir

on

Tra

nsp

ort

to

Blo

wd

ow

n

Boiler Pressure (psig)

Solus AP Iron Transport Performance in GE Research Boilers

Benchmark

Solus AP

Solus AP Terpolymer

Polymethacrylate Benchmark

Reduced sludge accumulation

Solus AP Magnesium Transport

Performance in GE Research Boilers

Solus AP Terpolymer

Polymethacrylate Benchmark

Reduced sludge accumulation via enhanced contaminant rejection to blowdown

0

20

40

60

80

100

120

Ca Transport % Fe Transport % Mg Transport % SiO2 Transport %

Solus AP Contaminant Transport Profile at 300 psig

Solus AP

None

Dosing Forgiveness

Feedwater upset recovery performance

Feedwater upset recovery performance

GE Research Boiler On-line deposit removal evaluation

300 psig/ Magnesium silicate-dominated deposit

Deposit formed under upset conditions without Solus AP

After Solus AP Treatment for

upset recovery

Ease of application

and control

Ease of application and control

• Stable, non-corrosive, liquid product

• Fully compatible with automated feed systems

• May be fed neat or diluted with high quality water

• Stable, non-volatile, product tracer provides

accurate & convenient dosing control & verification

• Compatible with existing polymer storage and feed

system alloys, elastomers & plastics

Field

Performance

Watertube Boiler Steam Drum Conventional All-Polymer – Prior to Solus AP

Before

170 psig D-Type Watertube Boiler August 2012 Inspection

Benchmark Polymer 2 All-Polymer Program

Steam drum surface Waterside of boiler tube

170 psig D-Type Watertube Boiler August 2013 Inspection

One year on Solus AP All-Polymer Program

Steam drum surface Tubes under belly plate

Watertube Boiler Steam Drum One Year After Initiation of Solus AP Treatment

Q&A