Water Arabia 2011 Conference and Exhibit. Gulf Hotel-Manama, Kingdom of Bahrain January 31, February 1 & 2, 2011.

Transcription

1 Water Arabia 2011 Conference and Exhibit. Gulf Hotel-Manama, Kingdom of Bahrain January 31, February 1 & 2, Chlorine dioxide as a successful antifoulant treatment in large cooling system-case history Giuseppe Petrucci ISIA INTERNATINAL FZC DUBAI-UAE Cl2 technologies and service UNDERWATER TECH. Cl

2 ILFIELD BICIDE TREATMENT Seawater antifouling Treatment PAPER MILLS FD AND BEVERAGE INDUSTRY ISIA INTERNATINAL activities in water disinfection WASTE WATER DESALINATIN PRCESS PTABLE WATER Cl2 UNDERWATER TECH Chlorine dioxide technology

3 ILFIELD BICIDE TREATMENT SEAWATER ANTIFULING TREATMENT PAPER MILLS ISIA SISTEMI activities in water FD AND disinfection BEVERAGE INDUSTRY WASTE WATER DESALINATIN PRCESS PTABLE WATER Cl2 UNDERWATER Chlorine dioxide technology SEAWATER ANTIFULING TREATMENT Power plant Petrochemical plant Refinery Steel mills Fertilizer plant Thermal and R.. desalination plant make up

4 CHLRINE DIXIDE CHARACTERISTICS CHARACTERISTICS SUITABLE FR: b io cid a l a ct iv ity % p H chlorine dioxide 9 chlorine The biocidal activity is constant over the ph 6-9 u sea water once-through cooling system (ph 8.5) u recirculating cooling water system (ph > 8) H H N H H No reaction with ammonia and urea u fertiliser & ammonia plant cooling system u waste water Cl rganic No reaction with organic matter and oil u refinery and petrochemical cooling system u seawater desalination plant Cl

5 CHLRINE DIXIDE CHARACTERISTICS CHARACTERISTICS SUITABLE FR: TTHMs pecursors Cl No formation of halogenated compounds (TTHMs-dangerous for human health) u potable waterworks u food and beverage industry u waste water treat. plants sulfate reducing bacteria Cl Strong biocidal activity against anaerobic bacteria u minimize corrosion Cl Fe S xidation of sulfide to sulfate (sulfide scavenger) u minimize corrosion u minimize bad smell

6 CHLRINE DIXIDE Cl 2 + e - ---> Cl 2 - (E o = 0,95 V) Cl H e - ---> Cl H 2 (E o = 1,51 V) Chlorine Dioxide is very active against: - bacteria - viruses - algae - fungi -macroorganism

7 CHLRINE SPECIES FRMATIN IN WATER ACCRDING T ph chlorine species in solution % Cl 2 HCl Cl ,5 1 1,5 2 2,5 3 3,5 4 4,5 5 5,5 6 ph 6,5 7 7,5 8 8,5 9 9,5 10

8 Bacteria wall Bacteria colony x Cl - STILL ALIVE NEW GRWING STILL ALIVE STILL ALIVE Cl 2 - Cl 2 - Cl 2 - N growing

9 CHEMICAL FEATURES F CHLRINE DIXIDE (Cl 2 ) 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

10 MICRFULING The Biofouling problem Bacteria, Algae, Fungi, Microbial corrosion Loss of the heat exchange (loss in the efficiency of the thermal cycle) MACRFULING Mussels, Barnacles, Serpulid worms, Hidroys Encrusting, loss of water flow, tubes plugging corrosion under deposit.

11 Chlorine dioxide and chlorine comparison against bacteria 100 Cl2 and Cl2 effectiveness in seawater at ph 8,2 - Cl2 demand = 1,7 mg/l - Cl2 demand = 0,9 mg/l Cl2 1,0 mg/l rganism survival % Cl2 3,0 mg/l Cl2 0,3 mg/l 10 0 Cl2 1 mg/l Contact time second

12 CHLRINE DIXIDE AND CHLRINE CMPARISN N MACRFULING GRWTH Kg/m2*y Cl2 Cl2 blank 20 Dosage mg/l 10 0 Summer - Cl Cl2 0.4 apr- 99 mag- 99 giu- 99 lug- 99 ago- 99 set- 99 ott- 99 nov- 99 dic- 99 gen- 00 feb- 00 mar- 00 Winter - Cl Cl2 0.2

13 CHLRINE DIXIDE AND CHLRINE CMPARISN N THM FRMATIN IN SEAWATER HAVING A TC F 5 MG/L 800 total THM ppb CHLRINE 35 C 25 C 15 C CHLRINE DIXIDE 35 C 25 C 15 C contact time 60 minute contact time 20 minute dosage rate mg/l ,5 contact time 10 minute From environmental impact of biocidal antifouling alternative treatments of seawater once through cooling systems R. Ambrogi ENEL

14 CHLRINE DIXIDE 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

15 CHLRINE DIXIDE GENERATIN Cl 2 can be generated on site by using water solutions of: Sodium Chlorite,Hypochlorite and acid according to the following reaction: r by using Sodium Chlorite and Chlorine 2NaCl2 + NaCl + 2HCl 2Cl2 + 3NaCl + H2 according to the following reaction: r by using Sodium Chlorite and Hydrochloric Acid according to the following reaction: 2 NaCl 2 + Cl 2 --> 2 Cl NaCl 5 NaCl HCl --> 4 Cl NaCl + 2 H 2

16 ph Chlorine dioxide to dosage point ph NaCl from electrochlorinator HCl 33% Sodium chlorite

17 Chlorine dioxide to dosage point Chlorinated water Sodium chlorite

18 Cl2 hypochlorite generating system Conversion of hypochlorite from electrochlorinator into Chlorine Dioxide

19 Cl2 under water generating system Reaction chamber located into the dilution water line Water to be disinfected Water to be disinfected NaCl 2 H 2 HCl H 2 Cl 2 Dilution H 2 Cl2 Water solution

20

21 Cl 2 ISIA SISTEMI

22 Chlorine dioxide reagents storage tanks

23 Chlorine dioxide reagents pumping station and control monitoring system

24 Chlorine dioxide underwater reaction chambers

25 water basin after 18 month operation. Reaction chambers located inside the racket pipe

26 Description of the Facility and Cooling Water (PLANT 1) PLANT: FEEDING: SYSTEM: FLWRATE: LARGE PETRCHEMICAL SEAWATER FRM THE INTAKE BASIN, SCREEN FILTERS, PUMPING STATIN BASINS, CLING TWERS BASIN, HEAT EXCHANGERS, RETURN T THE TWERS, BLW DWN T THE SEA. RR. 175,000 m3/h (full capacity) CHLRINE DIXIDE DSAGE: from March to ctober 2 shot/day at 0.5 ppm as long as 1.5 hour each shot (TTAL 3 H/DAY). Winter 2 shot/day at 0.5 ppm as long as 1 hour each shot (TTAL 2 H/DAY). DSAGE START UP: February 2009.

27 Description of the Facility and Cooling Water (PLANT 2) PLANT: FEEDING: LARGE PETRCHEMICAL SEAWATER FRM THE INTAKE SYSTEM: SCREEN FILTERS, PUMPING STATIN, PUMPING STATIN, HEAT EXCHANGERS, RETURN T THE T THE SEA. FLWRATE: 32,000 m3/h (full capacity) CHLRINE DIXIDE DSAGE: 2 shot/day at 0.3 ppm as long as 1 hour each shot (TTAL 2 H/DAY). DSAGE START UP: February 2009.

28 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.

29 EasyaReadox SYSTEM electrochemical biofilm sensor.

30 As chlorine dioxide shots increase, the baseline come back to its original value showing no biofilm activity

31 Constant baseline value indicates that no biofilm activity takes place and the whole system is clean.

32 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.

33 أشكركم على حسن ضیافتكم واھتمامكم Thank you very much for your hospitality and your kind attention Cl For further information: ISIA INTERNATINAL FZC Dubai Airport Free Zone Authority ffice 238-6WB P..Box DUBAI-UAE Tel (0) Fax. +971(0) e.mail: