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_06202006-1
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_06202006-2
The Price of Deposition Quebec City_06202006-3
The Price of Deposition - Reliability Surprises! Unscheduled Downtime Budget Variances Quebec City_06202006-4
RELIABILITY Quebec City_06202006-5
The Price of Deposition - Safety Threat to Personnel! Threat to Equipment Quebec City_06202006-6
SAFETY Quebec City_06202006-7
The Price of Deposition - Economy Fuel to Energy Conversion Heat transfer efficiency Quebec City_06202006-8
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 1/64 1 2 3 4 5 6 7 8 9 % Loss of Heat Transfer Quebec City_06202006-9
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 310 25 20 16 15.6 15 8.8 7 0.7 0.6 Quebec City_06202006-10
ECONOMY Quebec City_06202006-11
Evaluating your Boiler s Health Quebec City_06202006-12
The Decision to Clean Risk $$ Chemical Cleaning Cost $$ Elapsed Time Since Chemical Cleaning Quebec City_06202006-13
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_06202006-14
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_06202006-15
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_06202006-16
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 2 @ < 1000 psig 12 20 g/ft 2 @ > 1000 psig and ALL BLRBs Survey says = 52% data based Both Time and Data Based Survey says = 18% Quebec City_06202006-17
Evaluating your Boiler s Health When to Clean? Tube Sample Protocol Tube portion to be removed 2 feet 0 1 1 2 feet 0 2 1 2 feet 0 3 1 2 feet 0 4 Year 0 Year 1 Year 2 Year 3 Year 4 Quebec City_06202006-18
The Cleaning Process Safety Pre-engineering / Consultation Preparation and Execution Post cleaning evaluation Quebec City_06202006-19
Alternatives to Cleaning Options? Quebec City_06202006-20
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_06202006-21
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_06202006-22
Chemical Options Boiler Water Dispersant 1000 Canadian Kraft Mill Recovery Boiler - Iron Transport 900 Start of Dispersant Trial 800 700 600 500 400 300 200 100 0 23-Aug-94 21-Dec-94 23-Mar-95 19-Jul-95 12-Oct-95 9-Jan-96 3-Apr-96 20-Apr-96 23-Apr-96 29-Apr-96 10-Jun-96 10-Jul-96 12-Aug-96 29-Aug-96 30-Sep-96 21-Oct-96 18-Nov-96 16-Dec-96 13-Jan-97 26-Feb-97 17-Mar-97 7-Apr-97 9-Jul-97 17-Sep-97 6-Nov-97 14-Jan-98 12-Mar-98 12-May-98 24-Mar-99 16-Jun-99 21-Sep-99 20-Jan-00 ppb Boiler coming on-line Quebec City_06202006-23
Chemical Options Boiler Water Dispersant Midwest Paper Mill Blowdown Iron Total Iron, ppb 450 400 350 300 250 200 150 100 50 0 1500 psig 75-100 cycles 5 ppb FW Iron Start Dispersant Here 1 4 7 10131619222528313437404346495255586164677073 Sample Day Quebec City_06202006-24
Southern U.S. Paper Mill Deposit Loading History DWD - g / ft 2 50 45 40 35 30 25 20 15 10 5 0 Acid Cleaned Acid Cleaned Started HTP-2 1989 1990 1991 1992 1993 1994 1995 Quebec City_06202006-25
Monitoring Decision Making Data Quebec City_06202006-26
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_06202006-27
Operating Costs Summary Pay Now or Pay Later Treatment Costs Cleaning Costs Quebec City_06202006-28
Postpone, maybe?. Do it sometime, for sure! Quebec City_06202006-29
Questions? Quebec City_06202006-30