AMMONIA CONDENSERS WATER TREATMENT BEST PRACTICES

PETER BRUNO JUSTIN SPRINGER

1

5/9/18

DISTRICT MANAGER – WISCONSIN AREA MANAGER – SOUTHERN WISCONSIN

Agenda

Why Treat Ammonia Condensers?

Initial Passivation

Galvanizing and White Rust Awareness

Stainless Steel Condenser Considerations

Treatment Options

Questions

Why Treat Ammonia Condensers

Ensure asset protection

Optimize energy efficiency

Manage water usage

Minimize health risk MICROBIO

CORROSION

Evaporative Cooling – Common Issues

Typically poor water distribution

- Makeup

- Circulation

- Mineral Concentration

- Small basins

Blowdown and water chemistry control

Galvanized metallurgy

Condenser Configuration - Common or Central Sump

Raw Water

Make-up

Blowdown

Trasar

• Multiple Condensers

• Common Sump

• Chemistry balance

The Common sump system makes it easier to chemically treat.

Initial Passivation

Best Practices for Galvanized Condensers

• 1ST option : Phosphate based treatment

• 2ND option : Zinc based treatment (AZ Lite )

• Re-passivate after major shutdown or

maintenance

Initial Passivation

Best Practices for Galvanized Condensers

Galvanized Condensers

Galvanize passivation is not bullet proof. Even with good control some customers still experience white rusting.

Passivation just reduces the risk of white rusting.

15

Initial Passivation Best Practices for Stainless Steel Condensers

Clean and passivate based on other metallurgy in the system – Copper, Mild Steel etc.

If only stainless Steel in system

First 72 hours of operation 1.5-2X the Scale and corrosion inhibitor

Use Surfactant (Nalprep) during the first 72

▪Removal of oils and biofilm

Scale and Corrosion

GALVANIZED CONDENSERS

17

HEAD PRESSUREScaling and Fouling

Insulates tube bundle

Condensing less efficient

Compressors must work harder to achieve liquid state (0.67 kw/ton)

Higher compressor head pressure…more electricity consumed

~2.5% energy per 5-psi head pressure change

1,000 tons refrigeration costs

~$400,000/yr in electricity

Reference : BAC bulletin SEN5M/03/00

HEAD PRESSUREScaling and Fouling

Reference : BAC bulletin SEN5M/03/00

HEAD PRESSUREScaling and Fouling

Reference : BAC bulletin SEN5M/03/00

HEAD PRESSUREMist Eliminators

Reduces forced air flow

Condensing less efficient

Compressors must work harder to achieve liquid state

Higher compressor head pressure…more electricity consumed

~2% energy loss for plugged eliminators

HEAD PRESSURESpray Pattern

Reduces condensing efficiency

Increases potential for scaling

Results in more condensers than needed

HEAD PRESSURESpray Nozzles

Must have regular maintenance and inspection

Proper pressure and circulation

Recommend minimum quarterly inspection

AMMONIA REFRIGERATIONOther Challenges

Purge of non-condensable

Ammonia leak-nitrifying bacteria

Circulation capacity

Annual cleaning

External water leaks

AMMONIA REFRIGERATIONGalvanizing and White Rust

Porous zinc carbonate-rapidly formed in pH>8.3

AMMONIA REFRIGERATIONGalvanizing and White Rust

White, fluffy or waxy non-protective zinc corrosion product

Can be removed mechanically

AMMONIA REFRIGERATIONGalvanizing and White Rust

Erodes over time leaving iron exposed

When zinc consumed, iron corrodes rapidly in aerated, warm environment

Stress Corrosion Cracking

STAINLESS STEEL CONDENSERS

29

Stress Corrosion Cracking

Stress Corrosion Cracking

▪The combination of a stress within the metal and a specific corrosive species that results in a crack

▪Cracking does not occur due to stress on its own or the corrosive species on its own. Both need to be present at the same time

31

Stress Corrosion Cracking

The cracks have a typical branching type structure

Stainless Sandvik Risk Curve

AMMONIA REFRIGERATIONAcid Feeding and Ammonia Condensers

Common sump only…never individual integral sumps

Proper pump, tubing and connector material

Secondary containment of tubing

Mixing required

Redundant controllers or 3D controller

External alarm to light or horn

Centrifugal pump

NH3 In

NH3 Out

Circulating Pump

Open tankCommon Sump

Sample Line for

Trasar, pH, Conductivity, etc.

Minimum 10 gpm.

Recommended: Walchem WPH310 pH Controller

(021-CL1008.88)

Corrosion/Scale

Inhibitor

Open tankSulfuric Acid Drum

Separate by 3-ft minimum

Recommended:

Polyethylene Tube

(100-ft, 001-H00024.88)

Biocide

Recommended:

LMI 38 gpd Pump

B111-92S

(001-H02160.88)

Includes: Kynar head,

injection valve, foot valve

and 16-ft of polyethylene

tubing

Recommended:

Kynar lined corp stop

(231-P6036.88)

Containment Basin

Recommended: 2-drums

(241-CW1012.88)

1. Acid feed is not recommended for systems without a common or remote sump.

2. pH controller must send alarm signal to light and/or alarm in both the sump area and plant engineering office.

3. Containment basin must be checked and logged daily for acid leaks.

4. Acid feed pump must be permanently mounted.

5. Acid feed tubing must be enclosed in Schedule 80 PVC pipe and graded to drain back to containment basin.

6. Acid feed pump must be tied to circulating pump control loop. No chemical feed is allowed if system in not

circulating.

7. The recommended sample line is 3/4-Schedule 80 PVC pipe.

Ammonia

Condenser(s)

Optional neat feed of

acid to mix area or

using dilution trough.

AMMONIA REFRIGERATIONIf no Acid Feed Available

White Rust Inhibitor is an option▪Base feed of 50 ppm along with scale and

corrosion inhibitor

Summary

Good passivation is a must to minimizing white rust formation.

Follow the manufacturer guidelines for passivation and chemical control.

An program that utilizes acid may be the only solution for long term control of white rust.

35

Questions

Thank You!

Peter Bruno

District Manager - Wisconsin

920-915-6618

Justin Springer

Area Manager – Southern Wisconsin

608-770-9798