water arabia 2011 conference and exhibit. · 2013. 2. 9. · water arabia 2011 conference and...
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Water Arabia 2011 Conference and Exhibit.Gulf Hotel-Manama, Kingdom of Bahrain
January 31, February 1 & 2, 2011.
Chlorine dioxide as a successful antifoulant treatment in large cooling system-Case history
Giuseppe Petrucci
ISIA INTERNATIONAL FZCO DUBAI-UAEClO2 technologies and service“UNDERWATER TECH.”
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ISIA INTERNATIONALactivities in
water disinfection
ClO2 UNDERWATER TECHChlorine dioxidetechnology
POTABLE WATER
Seawater antifouling Treatment
OILFIELDBIOCIDETREATMENT
WASTE WATER
FOOD ANDBEVERAGEINDUSTRY
PAPER MILLS
DESALINATION PROCESS
SEAWATER ANTIFOULING TREATMENT
•Power plant•Petrochemical plant•Refinery•Steel mills•Fertilizer plant•Thermal and R.O. desalination plant make up
ISIA SISTEMIISIA SISTEMIactivities in activities in water water disinfectiondisinfection
ClO2 UNDERWATERChlorine dioxidetechnology
POTABLE WATER
SEAWATERANTIFOULINGTREATMENT
OILFIELDBIOCIDETREATMENT
WASTE WATER
FOOD ANDBEVERAGEINDUSTRY
PAPER MILLS
DESALINATION PROCESS
CHLORINE DIOXIDE CHARACTERISTICS
4 5 6 7 8 9 10 11
01 02030405060708090
100
bio
cida
l act
ivity
%
p H
chlorine dioxide
chlorine
CHARACTERISTICS SUITABLE FOR:
u sea water once-throughcooling system (pH 8.5)
u recirculating coolingwater system (pH > 8)
u fertiliser & ammonia plantcooling system
u waste water
u refinery and petrochemicalcooling system
u seawater desalination plant
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The biocidal activityis constant over thepH 6 - 9
HH
HH
NN
HHHH
No reaction withammonia and urea
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OrganicOrganicNo reaction withorganic matterand oil
CHARACTERISTICS SUITABLE FOR:
u potable waterworksu food and beverage industryu waste water treat. plants
u minimize corrosion
u minimize corrosionu minimize bad smell
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TTHMs TTHMs pecursorspecursors No formation of
halogenatedcompounds(TTHMs-dangerousfor human health)
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sulfate sulfate reducing reducing bacteriabacteria Strong biocidal
activity againstanaerobic bacteria
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SS
FeFe
Oxidation ofsulfide to sulfate(sulfide scavenger)
CHLORINE DIOXIDE CHARACTERISTICS
CHLORINE DIOXIDE
Chlorine Dioxide is very active against:
ClO2 + e- ---> ClO2- (Eo = 0,95 V)
ClO2 + 4 H+ + 5 e- ---> Cl- + 2 H2O (Eo = 1,51 V)
-- bacteriabacteria-- virusesviruses-- algae algae -- fungifungi--macroorganismmacroorganism
0 0,5 1 1,5 2 2,5 3 3,5 4 4,5 5 5,5 6 6,5 7 7,5 8 8,5 9 9,5 10
0
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chlo
rine
spec
ies
in s
olut
ion
%
pH
2ClHOCl
OCl-
CHLORINE SPECIES FORMATION IN WATER ACCORDING TO pH
ClO2-
ClO2-
NOgrowing
Bacteria colony
NEWGROWING
STILL ALIVE
STILL ALIVE
STILL ALIVE
Cl-
ClO2-
Bacteria wall
--
--
-
-
---
-
x
CHEMICAL FEATURES OF CHLORINE DIOXIDE (ClO2)
u it is a gas and must be generated on site
u it is soluble in water
u it does not undergo hydrolysis at pH of cooling water
u it is a strong oxidising agent
MICROFOULINGMICROFOULING
MACROFOULINGMACROFOULING
• Bacteria, Algae, Fungi, • Microbial corrosion• Loss of the heat exchange (loss in
the efficiency of the thermal cycle)
•• Mussels, Barnacles, Serpulid worms, Hidroys
• Encrusting, loss of water flow, tubes plugging corrosion under deposit.
The Biofouling problem
ClO2 and Cl2 effectiveness in seawater at pH 8,2
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0 30 60 90 120 150 180 210 240 270 300
Contact time second
Org
anis
m s
urvi
val %
Cl2 1,0 mg/l
ClO2 0,3 mg/l
Cl2 3,0 mg/l
ClO2 1 mg/l
- Cl2 demand = 1,7 mg/l- ClO2 demand = 0,9 mg/l
Chlorine dioxide and chlorine comparison against bacteria
apr-99
mag-99
giu-99
lug-99
ago-99
set-99
ott-99
nov-99
dic-99
gen-00
feb-00
mar-00
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ClO2Cl2blank
Kg/m2*y
Dosage mg/l
Summer- Cl2 2.0- ClO2 0.4
Winter- Cl2 1.3- ClO2 0.2
CHLORINE DIOXIDE AND CHLORINE COMPARISON ON MACROFOULING GROWTH
20 2 1 0,5
0
100
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800
CHLORINE
15°C25°C
35°C
25°C
CHLORINEDIOXIDE
15°C
35°C
dosage rate mg/l
total THM ppb
contact time 60 minute
contact time 20 minute
CHLORINE DIOXIDE AND CHLORINE COMPARISON ON THM FORMATION IN SEAWATER HAVING
A TOC OF 5 MG/L
contact time 10 minute
From “ environmental impact of biocidal anti fouling al ternative treatments of seawater once through cooling systems ”R. Ambrogi ENEL
CHLORINE DIOXIDE ADVANTAGES
u very performant in short time contact system
u reduced corrosion (compared with chlorine)
u very performant at high pH (sea water, all organic and Zn/phosphonate treat.)
u very performant in ammonia contaminated system (fertilizer and ammonia plant)
u It can be applied by a simply chlorine plant modification or possibility no chlorine treatment
u environment friendly disinfection treatment
CHLORINE DIOXIDE GENERATIONClO2 can be generated on site by using water solutions of:
Sodium Chlorite,Hypochlorite and acid according to the following reaction:
2NaClO2 + NaClO + 2HCl 2ClO2 + 3NaCl + H2O
Or by using
Sodium Chlorite and Chlorine
according to the following reaction:
2 NaClO2 + Cl2 --> 2 ClO2+ 2 NaCl
Or by using
Sodium Chlorite and Hydrochloric Acid
according to the following reaction:
5 NaClO2 + 4 HCl --> 4 ClO2+ 5 NaCl + 2 H2O
pH
pH
NaClO fromelectrochlorinator
Chlorine dioxideto dosage point
HCl 33% Sodium chlorite
Chlorine dioxideto dosage point
Sodium chlorite
Chlorinated water
ClO2 “hypochlorite” generating system Conversion of hypochlorite from electrochlorinator into Chlorine Dioxide
HClNaClO2
Dilution H2O
Water to be disinfected
Water to be disinfected
H2O
H2O
ClO2Water solution
ClO2 “under water” generating system Reaction chamber located into the dilution water line
ClO2
ClO2
ISIA SISTEMI
Chlorine dioxide reagents storage tanks
Chlorine dioxide reagents pumping station and control monitoring system
Chlorine dioxide “underwater reaction chambers”
Reaction chambers located inside the racket pipe
water basin after 18 month operation.
Description of the Facility and Cooling Water(PLANT 1)
PLANT: LARGE PETROCHEMICAL
FEEDING: SEAWATER FROM THE INTAKE
SYSTEM: BASIN, SCREEN FILTERS, PUMPING STATION BASINS, COOLING TOWERS BASIN, HEAT EXCHANGERS, RETURN TO THE TOWERS,BLOW DOWN TO THE SEA.
FLOWRATE: RR. 175,000 m3/h (full capacity)
CHLORINE DIOXIDE DOSAGE: from March to October 2 shot/day at 0.5 ppm as long as 1.5 hour each shot (TOTAL 3 H/DAY). Winter 2 shot/day at 0.5 ppm as long as 1 hour each shot(TOTAL 2 H/DAY).
DOSAGE START UP: February 2009.
Description of the Facility and Cooling Water (PLANT 2)
PLANT: LARGE PETROCHEMICAL
FEEDING: SEAWATER FROM THE INTAKE
SYSTEM: SCREEN FILTERS, PUMPING STATION, PUMPING STATION, HEAT EXCHANGERS, RETURN TO THE TO THE SEA.
FLOWRATE: 32,000 m3/h (full capacity)
CHLORINE DIOXIDE DOSAGE: 2 shot/day at 0.3 ppm as long as 1 hour each shot (TOTAL 2 H/DAY).
DOSAGE START UP: February 2009.
Why chlorine dioxide?
Chlorine dioxide was selected, to treat the 2 plants instead of chlorination for safety, environmental and performance reasons.
In fact, chlorine and sodium hypochlorite are responsible of bromate and bromoform formation in seawater which are considered very toxic for aquatic life of the Arabian Gulf.
Chlorine dioxide demonstrated to be very efficient at very low dosage rate, minimizing its residual and the formation of brominated compounds at the discharge point.
EasyaReadox SYSTEM
electrochemical biofilm sensor.
EasyaReadox SYSTEM
electrochemical biofilm sensor.
As chlorine dioxide shots increase, the baseline come back to its original value showing no biofilm activity
Constant baseline value indicates that no biofilm activity takes place and the whole system is clean.
Conclusions
We underline the following advantages:
•Chlorine dioxide has allowed to minimize the growing of both micro and macro-fouling inside cooling systems of petrochemical plants at very low dosage rate,
•Monitoring system has demonstrated to be the “Brain” of the treatment programme. It has permitted to inject chlorine dioxide in a proper quantity and in the right moment, saving material and protecting the environment.
أشكركم على حسن ضیافتكم واھتمامكم Thank you very much for your hospitality and your
kind attention
ISIA INTERNATIONAL FZCO Dubai Airport Free Zone Authority
Office 238- 6WB P.O.Box 293896-DUBAI-UAE
Tel. +971.(0)47017959Fax. +971(0)47017962
e.mail: [email protected]
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For further information: