Transcript HARTSFIELD AIRPORT WATER TREATMENT SEMINAR

COOLING SYSTEMS
WATER TREATMENT
TRAINING
Presented by
A and W
TECHNOLOGIES
Plant Refrigeration Costs
Electricity
20%
59%
Equipment
Depreciation
Labor
Makeup Cost
13%
2% 5%
1%
Sewer Cost
Water Treatment
NUMBER 1 PRIORITY
SAFETY
THINK
COOLING WATER
IMPURITIES

TYPICAL IMPURITIES
– Ions
Calcium, Magnesium, Sulfate, Silica, chlorides
All can react to form harmful deposits
– pH
Increasing pH - increased scale potential
Decreasing pH - increased corrosion potential
COOLING WATER
IMPURITIES

Characteristics
–
–
–
–
–
–
–
–
pH
M alkalinity
Chorides
Hardness
Silica
Iron
Conductivity
Copper
City Water
Well
7.2
0 ppm
12 ppm
17 ppm
4.2 ppm
.05 to .5 ppm
60 mmhos
.1 ppm
7.3
71
2.3
68
23
.5
160 - 185
.1
FORCED DRAFT TOWER
Condenser Water
HOT WELL
EVAPORATION
FAN
Fill
Solenoid valve
Blowdown line
to drain
MAKEUP water meter
WELL & CITY
3 Chillers
COLD WELL
Recirculation pumps
A and W
TECHNOLOGIES
Forced Draft Tower
Blowdown
MAKEUP
Water Meter
PROCESS
74*F
90*F
NATURAL DRAFT TOWER
500’
500,000 GPM
10* F Delta T - Approach
Power Generating Station
Water distribution
Evaporative
Condensor
Chillwater
in the tubes
or ammonia
?
Makeup water
To chemical
feed center
Recirculation pump
•BAC Evaporative condensor
Chicken plants and food manufacturers
Hey
what the
heck is that?
COOLING WATER

OPERATIONAL FACTORS
– Evaporation
= (Recirc. Rate x Delta T x .001) = GPM
Pure water leaves
Solids concentrate
Requires fresh water makeup to be added
– Blowdown
Equal to Evaporation
Cycles - 1
– Cycles
Equal to Conductivity in Tower
Conductivity in Makeup
*Makeup =
Evap + BD
Typical Specifications

Evaporation
» 5000 x 10 x 70% x 24 x .06 = 50,400 GPD

Blowdown
» 50,400 / 5-1 = 12,600 GPD

Makeup = Evap + BD
» 50,400 + 12,600= 63,000 GPD
Typical Specifications

Evaporation Credits
» 4220 x 10 x 60% x 24 x .06 = 36,461 GPD

At 365 days per year this is 13,308,265 GPY

Sewer charge is $2.75 per 1000 gallons

13,308,265/1000 = 13,308 x $2.75 = $36,597
Optimizing Cycles
40
35
Tower
30
25
20
15
10
5
0
1
2
3
Cycles
4
5
6
7
Saves Water
40
35
30
25
20
15
10
5
0
1
2
3
Cycles
4
5
6
7
COOLING WATER
PROBLEMS

CORROSION
– Tendency for metal to revert to its natural
state
– Electrochemical reaction
– Anode, cathode, source of electron flow
and an electrolyte
– General thinning and/or pitting
– Galvanic corrosion
At the Anode
One end of the “battery”
Fe++
Anode
e- e- e - e- e-
Fe = Fe++ + 2e-
At the Cathode
The other end completes the circuit!
OHe1/ O
2 2
e-
e-
e-
e-
+ H2O + 2e-
H2O
Cathode
= 2OH-
O2
Corrosion Products Form
Result:
OHFe++
Fe(OH)2
2
Anode
Anode
OHCathode
Fe++ + 2OH- = Fe(OH)2
COOLING WATER
TREATMENT

CORROSION CONTROL
– Without it....
Destruction of equipment
Plant downtime due to equipment failure
Decreased efficiency / decreased heat
transfer
COOLING WATER
TREATMENT

CORROSION CONTROL
– Anodic inhibitors
– Cathodic inhibitors
Continuous feed must be maintained to
keep the protective film in place !!
Control of blowdown / pH critical to
success!!
A and W
Cooling
Products
A and W Technologies
Three-Part Corrosion Protection
 Deposit Protection
 Molybdate Tracer
 Medium to High pH

A and W Inhibitors.
 Passivates Anodic Sites
 Protects Cathodic Sites
 Shields Copper Surfaces
..
A and W
To Protect
and to
Serve
Reliable Corrosion Protection
1. Anodic Protection
O2
O2
------------------------ -iron oxide----------------------e-
e-
A and W Inhibitors Passivate the Steel
With A and W . . .
COOLING WATER
PROBLEMS

SCALE
– Crystalline structure
– Combinations of cations and anions
– Water analysis can provide scaling indices
to determine scale forming potential
– Inversely soluble
» As temperature increases solubility decreases
(scale can come out of solution)
COOLING WATER
PROBLEMS

FOULING
– Accumulation of organic / inorganic
material
– Examples:
Biological slimes
Algae
Corrosion products
Airborne dirt and debris
– Subject to flow velocities
– Organic fouling can be found throughout
A and W Inhibitors . . .
Technology
Suspends Contaminants
A and W Inhibitors . . .
Patented Technology
Suspends Contaminants
Inhibits Scale Formation
A and W Inhibitors . . .
Patented Technology
Suspends Contaminants
Inhibits Scale Formation
Allows High Cycles
A and W Inhibitors . . .
Patented Technology
Suspends Contaminants
Inhibits Scale Formation
Allows High Cycles
Maintains Heat Transfer
Efficiency
CHEMICAL FEED
CONDENSER WATER
A and W
TECHNOLOGIES
All pumps plug into controller. Blowdown solenoid also plugs into controller.
Signal from water meter back to controller if used. Power needs to be supplied to
the controller. 110VAC @ 10 amps.
3/4 INCH SCH. 80 PVC
Return to Tower
USE SCREWED TEES AT INJECTIONS
Supply line
CONTROLLER
A and W
CORROSION COUPON RACK
3/4 inch PVC pipe and screwed tees.
Notice orientation, with flow. Can be
constructed on site.
*Presently No Coupon Studies!
AWC
Awc 310
AWC
AWC
M-1015
M-1202
AWC
CL-1 & M92
COOLING WATER
TREATMENT

BIOLOGICAL CONTROL
Cooling water systems provide an excellent
environment for microbio activity
Fouling and underdeposit corrosion
Toxicant evaluations can determine the most
effective biocide
ALGAE
BUGS
COOLING WATER
TREATMENT

BIOLOGICAL CONTROL
– Oxidizing biocides “BURNS THE BUGS”
Chlorine, bromine, sodium hypochlorite
Provides quick kill
Fed at a rate exceeding the chlorine
demand plus 0.5 to 1 ppm free chlorine
residual for one to four hours
COOLING WATER
TREATMENT

BIOLOGICAL CONTROL
– Nonoxidizing biocides –
“POISONS OR STARVES ‘EM”
Used where chlorine demand is high or...
Supplemental biocide for chlorine
Remain in the system longer than
oxidizing biocides
Provides longer contact time for kill
TESTING AND CONTROL

SYSTEM TESTS
–
–
–
–
–
Conductivity (All systems)
pH (City, Tower, All closed loops)
Molybdenum (Tower, All closed loops)
Cycles (Tower)
Microbiological (Tower)
Data should be entered in log book or
monitored with computer trending
TROUBLESHOOTING
Low levels
 Algae in tower
 Tower losing water
 Closed loops losing water
 High head pressure on chillers
 Leaks on chemcials
 Bugs in Chillwater

Cooling Service Program
 Lab Analysis
– Water
– Deposit
– Metallurgical
 Test HX
 Equipment





Corrosion studies
Chiller efficiency studies
Micro-biological studies
Cooling tower wood analysis
LSI Calculations
Quality Assurance
AT&T
A and W Technologies
Thank you for the opportunity