Waterside Cleaning of Recovery Boilers.. Pay Now or Pay Later

Transcription

1 Waterside Cleaning of Recovery Boilers.. Pay Now or Pay Later Norris N. Johnston Application Team Manager Water Management Technology Lacey s Spring, Alabama USA Quebec City_

2 Waterside Cleaning of Recovery Boilers Introduction Recovery Boiler Emphasis The true topic of discussion Pay Now or Pay Later! The Price of Deposition Evaluating your Boiler s Health The Decision to Clean Options Summary Quebec City_

3 The Price of Deposition Quebec City_

4 The Price of Deposition - Reliability Surprises! Unscheduled Downtime Budget Variances Quebec City_

5 RELIABILITY Quebec City_

6 The Price of Deposition - Safety Threat to Personnel! Threat to Equipment Quebec City_

7 SAFETY Quebec City_

8 The Price of Deposition - Economy Fuel to Energy Conversion Heat transfer efficiency Quebec City_

9 The Price of Deposition - Economy 3/32 Normal phosphate sludge Deposit Thickness, inches 5/64 1/16 3/64 1/32 Sludge with 4% Fe Sludge with 8% Fe Sludge with 8% Fe & SiO 2 1/ % Loss of Heat Transfer Quebec City_

10 The Price of Deposition - Economy Selected Thermal Conductivity Values Material Boiler Steel Calcium Phosphate Magnetic Iron Oxide Calcium Sulfate Calcium Carbonate Magnesium Phosphate Analcite (NaO... Al 2 O 3 4SiO 2 2H 2 O) Fire Brick Insulating Brick Porous silicate scale Btu / hr-ft 2 -ºF/ inch Quebec City_

11 ECONOMY Quebec City_

12 Evaluating your Boiler s Health Quebec City_

13 The Decision to Clean Risk $$ Chemical Cleaning Cost $$ Elapsed Time Since Chemical Cleaning Quebec City_

14 Evaluating your Boiler s Health The Decision to Clean Convenience After Failure Company Policy -- Time and/or Data Based Engineering approach History: Failures, Excursions, Inspections System: Mechanical Treatment Data: Deposit data, BFW Quality Control: Duration and Severity of Excursions Internal boiler water treatment Quebec City_

15 Evaluating your Boiler s Health Cleaning Policy Enforced Independent Consultant Used? No 30% No 16% Yes No Yes No Yes 70% Yes 84% Quebec City_

16 Evaluating your Boiler s Health Cleaning Time Required > 48 h 44% 24 h 6% 36 h 22% 24 h 36 h 48 h > 48 h 48 h 28% Quebec City_

17 Evaluating your Boiler s Health When to Clean? Time Based Alstom (ABB/CE) = 7 years for Recovery Boilers Survey says = 30% time based Data Based B&W = 20 to 40 g/ft < 1000 psig g/ft > 1000 psig and ALL BLRBs Survey says = 52% data based Both Time and Data Based Survey says = 18% Quebec City_

18 Evaluating your Boiler s Health When to Clean? Tube Sample Protocol Tube portion to be removed 2 feet feet feet feet 0 4 Year 0 Year 1 Year 2 Year 3 Year 4 Quebec City_

19 The Cleaning Process Safety Pre-engineering / Consultation Preparation and Execution Post cleaning evaluation Quebec City_

20 Alternatives to Cleaning Options? Quebec City_

21 Mechanical Options Feedwater Makeup Demineralized water or better Redundant protection against contaminant intrusion Condensate Resin and/or Electromagnetic Filtration Polishers Redundant protection against contamination Quebec City_

22 Chemical Options Condensate Treatment Chemistry Appropriate treatment for existing metallurgy Passivating agent to maximize condensate return Internal Treatment Chemistry Congruent Phosphate with high purity feedwater Boiler water dispersant Quebec City_

23 Chemical Options Boiler Water Dispersant 1000 Canadian Kraft Mill Recovery Boiler - Iron Transport 900 Start of Dispersant Trial Aug Dec Mar Jul Oct-95 9-Jan-96 3-Apr Apr Apr Apr Jun Jul Aug Aug Sep Oct Nov Dec Jan Feb Mar-97 7-Apr-97 9-Jul Sep-97 6-Nov Jan Mar May Mar Jun Sep Jan-00 ppb Boiler coming on-line Quebec City_

24 Chemical Options Boiler Water Dispersant Midwest Paper Mill Blowdown Iron Total Iron, ppb psig cycles 5 ppb FW Iron Start Dispersant Here Sample Day Quebec City_

25 Southern U.S. Paper Mill Deposit Loading History DWD - g / ft Acid Cleaned Acid Cleaned Started HTP Quebec City_

26 Monitoring Decision Making Data Quebec City_

27 Best Practices Monitoring and Control PRV STG Cooling Water Low Pressure Steam Process Steam Users High Pressure Steam Dirty Condensate Multiple Effect Evaporator Fresh Steam Sweet Water Condenser Condenser Cooling Water Strong Black Liquor Superheater Weak Black Liquor from Washers Clean Condensate to Utilities Economizer Blowdown Flash Tank Pulp Mill Digester Paper Mill Feedwater Regulator Valve Deaerator HP Condensate HP Condensate Flash Tank Condensate Collection Tank LP Condensate Feedwater Storage Blowdown Heat Exchanger To Waste Feedwater Makeup Condensate Polisher (Resin and/or Magnetic ) Typical Sample Point Quebec City_

28 Operating Costs Summary Pay Now or Pay Later Treatment Costs Cleaning Costs Quebec City_

29 Postpone, maybe?. Do it sometime, for sure! Quebec City_

30 Questions? Quebec City_