APPENDIX E
Repair and Replacement Activities in Selected Industries

A summary of common repair and replacement activities for specific parts of a typical coal-fired power plant is given in Table E-1. The table does not attempt to summarize less frequent major replacements at a plant, such as repowering with a new furnace using an existing steam cycle or replacing major components (for example, a turbine generator) with an entirely new system.

Table E-2 presents the aggregated responses to a National Petrochemical and Refiners Association member survey, initiated in response to an information request from the committee. Sixty-four petroleum refineries responded to the survey, constituting half (8,808,122 barrels/day) of the total U.S. petroleum-refining capacity (16,894,314 barrels/day) (EIA 2004c). Table E-2 presents about 60 activities that typically are undertaken as repair and replacement at petroleum refineries. Each activity is listed with an estimate of how frequently it occurs and its cost. The cost of each activity is presented as a percentage of the total replacement cost of the major process unit with which the activity is associated. For example, replacing or repairing the fluidized catalytic cracking unit (FCCU) regenerator cyclones is estimated to occur at intervals of 3-5 years or longer. The cost of this activity is estimated to be up to 10% of the replacement cost of the FCCU. Because not all refineries are of the same size and configuration, there are likely to be variations in the replacement-cost percentages. The results presented in this survey, although not exhaustive, illustrate the diverse nature of repair and replacement activities typically undertaken at petroleum refineries.

Table E-3 lists repair and replacement and other activities peculiar to Kraft mills that are periodically undertaken. Both the structure of Table E-3



The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement



Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.

OCR for page 294
New Source Review for Stationary Sources of Air Pollution APPENDIX E Repair and Replacement Activities in Selected Industries A summary of common repair and replacement activities for specific parts of a typical coal-fired power plant is given in Table E-1. The table does not attempt to summarize less frequent major replacements at a plant, such as repowering with a new furnace using an existing steam cycle or replacing major components (for example, a turbine generator) with an entirely new system. Table E-2 presents the aggregated responses to a National Petrochemical and Refiners Association member survey, initiated in response to an information request from the committee. Sixty-four petroleum refineries responded to the survey, constituting half (8,808,122 barrels/day) of the total U.S. petroleum-refining capacity (16,894,314 barrels/day) (EIA 2004c). Table E-2 presents about 60 activities that typically are undertaken as repair and replacement at petroleum refineries. Each activity is listed with an estimate of how frequently it occurs and its cost. The cost of each activity is presented as a percentage of the total replacement cost of the major process unit with which the activity is associated. For example, replacing or repairing the fluidized catalytic cracking unit (FCCU) regenerator cyclones is estimated to occur at intervals of 3-5 years or longer. The cost of this activity is estimated to be up to 10% of the replacement cost of the FCCU. Because not all refineries are of the same size and configuration, there are likely to be variations in the replacement-cost percentages. The results presented in this survey, although not exhaustive, illustrate the diverse nature of repair and replacement activities typically undertaken at petroleum refineries. Table E-3 lists repair and replacement and other activities peculiar to Kraft mills that are periodically undertaken. Both the structure of Table E-3

OCR for page 294
New Source Review for Stationary Sources of Air Pollution and its contents were provided by representatives of International Paper, Inc., in response to an information request from the committee. Table E-3 lists about 90 repair and replacement activities that are periodically undertaken in a Kraft mill. For each activity, the table provides an estimate of how frequently the activity occurs, an estimate of how likely the activity is to occur within the specified interval, and the relative cost of the activity. The relative cost of the activity is presented as a percentage of the replacement cost of the major process component with which the activity is associated. For example, repairing or replacing the boiler safety relief valves is estimated with near certainty to be an annual activity at a Kraft mill, with an estimated cost that is less than 5% of the replacement cost of the entire boiler. Although the list of activities in Table E-3 is not certified as exhaustive, it illustrates a variety of repair and replacement activities that may be undertaken in pulp and paper manufacturing facilities. The repair and replacement activities presented here are expected to have different frequencies and costs among industrial sectors, production facilities, and types of process units because many factors, such as equipment design and operating conditions, affect their frequency and cost (R. Bessette, Council of Industrial Boiler Owners, November 10, 2004, letter to committee).

OCR for page 294
New Source Review for Stationary Sources of Air Pollution TABLE E-1 Summary of Common Repair and Replacement Activities, Frequencies, and Cost for Coal-Fired Electricity-Generating Facilities Category Description Repair or Replacement Needs Boiler-tube assemblies Rows or bundles of heat-exchanger tubes Wear and periodic failure attributable to erosion, corrosion, and temperature/pressure-related stresses, leading to such outcomes as leaks, forced outages, loss of reliability, and potential for substantial boiler failure Air heaters Heat exchangers that transfer heat from flue gas to incoming combustion air Exposure to ash, condensate, and acid gases in flue-gas path can lead to plugging, corrosion, and erosion, leading to loss of heat-transfer efficiency. Leakages or pluggage in the air preheater can reduce effective capacity at the plant Fans Forced-draft fans push combustion air into the furnace; induced-draft fans pull flue gas from the furnace. A balanced-draft system has both. Other typical fans include primary air fans for pneumatic transport of pulverized coal and flue-gas recirculation fans for NOx control Erosion and cyclic fatigue; fans exposed to flue gases often subject to higher temperatures as well as erosive ash and corrosive acid gases. Reduced effectiveness of fan reduces plant output; failure leads to shutdown Mills/feeders System for feeding and pulverizing coal into a fine powder Abrasion due to hard minerals in coal, and erosion where solids/powder strikes interior surfaces, including deterioration of rollers, tables, balls, classifiers, bearings, seals, motors, belts, flow-control devices, and piping Turbines and generators Steam turbines are composed of a shell, blades, nozzles, diaphragms, and rotors. Generators are composed of rotors and stators, including windings and insulation Turbine blades experience wear due to impurities in steam, requiring replacement of blades (usually with better designed shapes and more recently available alloys). Generator insulation can deteriorate because of exposure to heat or contaminants Condensers Typically, a shell and tube heat exchanger in which river water flows on the tube side and low-temperature steam and low pressure (at a vacuum compared with ambient) are on the shell side Flow on either side can lead to erosion. Impurities in steam or water can lead to corrosion. Biologic fouling on the water side is also possible. Partial or full pluggage of tubes reduces heat transfer, and tube failure leads to contamination of the steam cycle

OCR for page 294
New Source Review for Stationary Sources of Air Pollution Frequency Cost Considered to be common; entire tube assemblies replaced at nearly every boiler, as early as 5 years after the beginning of commercial operation Up to $40/kW to replace tube assemblies on a large boiler and potentially more on a smaller boiler Replacement in over 80% of units of basket layers and tubes. Seal replacement is also common Up to $6/kW on large boilers, higher costs per kW on smaller boilers Fans have been substantially replaced in over 70% of units Replacement of a large fan can cost up to $20/kW. Retrofitting a balanced-draft system in place of a forced-draft system can cost $70/kW Pulverizer mills have been replaced or substantially repaired in over 50% of units Replacing wear parts in a pulverizer mill can cost $2/kW and mill replacement can cost up to $5/kW Turbine blades or rotors have been replaced in more than 90% of units Turbine blade and rotor replacement can cost up to $20/kW. Replacement of the shell of the turbine can cost up to $60/kW More than 60% of units have replaced condenser tubes Tube bundle replacement can cost up to $10/kW

OCR for page 294
New Source Review for Stationary Sources of Air Pollution Category Description Repair or Replacement Needs Control systems Control and monitoring of boiler, turbine, and balance of plant management Control systems affect combustion efficiency and other operations of the plant. When systems fail and require replacement, replacement parts for the original design may no longer be available Coal and ash handling Unloading, storage, and conveying coal. Key subsystems include bulldozers (to manage the coal pile), conveyor belts, and bunkers (or silos) Wear of conveyor belts, motors, and other equipment; corrosion Feedwater heaters Heat exchangers, treatment system, and pumps to deliver, heat, and process water from the condenser to the economizer Leaking tubes lead to reduced efficiency. Plugged tubes lead to loss of capacity Sootblowers and water lances System for delivery of steam or compressor air to remove soot, ash, and slag from surfaces of such equipment as heat exchanger tubes Deterioration of sootblowers reduces effectiveness, which leads to less-efficient cleaning of surfaces. The latter can lead to losses or damage. For example, uncontrolled buildup of slag on boiler surfaces can lead to failure if large amounts of slag fall and damage boiler internals Burners Burner systems include tubes and, in some cases, annuli through which pulverized coal and staged air are introduced. Dampers, vanes, nozzles, windbox, flame scanners, and lighters are other typical components High temperatures, ash, and corrosive gases can lead to corrosion, erosion, and temperature-related stresses Motors Motors are used throughout a plant to drive pumps, belts, pulverizers, and other equipment. Motors can vary greatly in size Motor failures typically attributable to failure of insulation, which causes overheating and potential shortouts Electric equipment Equipment used to convert and transmit electricity in a form useful for internal plant end uses, such as motors, fans, and lighting Exposure to coal dust, temperatures in the plant, and other aspects of the plant environment can lead to shorts and overloads Pumps Pumps are used throughout the plant for feedwater, cooling water, and slurries (such as ash sluice). Pumps can be exposed to corrosive materials, erosive materials, and extremes of temperature and pressure Failure typically due to corrosion, erosion, and other demanding service conditions (such as high temperature and pressure)

OCR for page 294
New Source Review for Stationary Sources of Air Pollution Frequency Cost Replacement of pneumatic controls with solid-state, computerized, or automated controls has occurred in “most” units Replacement projects can cost up to $10/kW on larger units and $40/kW on smaller units Replacement of such components as conveyor belts, motors, and barge and rail unloaders is “common” Replacement of key components of coal handling can cost up to $4/kW. Replacement of key components of ash-handling systems can cost up to $14/kW More than 80% of units have replaced feedwater heaters or major tube bundles therein Replacement of a feedwater heater can cost up to $5/kW Sootblowers have been replaced at “most” units Replacement projects can cost up to $9/kW Replacements have occurred “one or more times at most units” Replacements can cost up to $30/kW Rewind or replacement of motors is “common” Replacements can cost up to $5/kW per motor Replacement of switchgear and other equipment is “very common” Replacement projects cost up to $9/kW Nearly 100% of units have overhauled or replaced boiler feedpumps Replacement projects can cost $10/kW

OCR for page 294
New Source Review for Stationary Sources of Air Pollution Category Description Repair or Replacement Needs Piping/ ducts/ expansion joints Pipes carry fluids or slurries. Ducts carry gases. Expansion joints are flexible connections between pipes or ducts Leaks can occur because of high-pressure, high-temperature environments or because of erosion or corrosion. Expansion joints can crack or separate Air compressors Compressed air is used for pneumatic drives, system controls, some sootblowers, and some power tools Moving parts are subject to typical wear. Reduced effectiveness of the compressor or failure can lead to reduced effectiveness or failure of other components (such as sootblowers and surfaces not adequately cleaned by failed sootblowers) SOURCE: ERCC 2002. Reprinted with permission; copyright 2002.

OCR for page 294
New Source Review for Stationary Sources of Air Pollution Frequency Cost Replacements of pipes, ducts, and expansion joints is “common” Repair and replacement can cost up to $23/kW Replacement is a typical choice, but frequency is not reported Replacement projects can cost up to $2/kW

OCR for page 294
New Source Review for Stationary Sources of Air Pollution TABLE E-2 Projected Repair and Replacement Frequencies and Relative Costs in Petroleum-Refinery Industry Activity Unit Estimated Frequency (years) Replacement Cost (% per unit) 1 3-5 5 >5 <5 5-10 10-20 >20 Pumps Replace pump seals All X X X   X X     Repair pumps All X       X       Replace pumps All       X X X   X Valves                   Replace valve packing All X X X X X       Replace valves All       X X       Catalysts Regenerate catalysts Reformer X       X       Replace catalysts Hydrotreaters   X     X       Replace catalysts SRU     X   X       Replace catalysts not specific X X X   X X     Column reactors Repair or replace trays and hardware All   X       X     Repair or replace reactor internals All   X     X       Replace weld overlays inside columns, vessels, and reactors All       X X X     Pressure safeties Repair, replace, test PSVs All   X     X       Exchangers Repair or replace exchanger All       X       X Repair or replace bundle All   X       X X   Clean tubes All   X     X       Crude unit Crude unit turnaround Crude   X X     X     Fluidized catalytic cracking unit (FCCU) FCCU turnaround FCCU   X X     X X X FCCU turnaround with cyclone replacement FCCU       X       X Replace or repair spent catalyst deflectors in an FCCU FCCU   X   X X      

OCR for page 294
New Source Review for Stationary Sources of Air Pollution Activity Unit Estimated Frequency (years) Replacement Cost (% per unit) 1 3-5 5 >5 <5 5-10 10-20 >20 Fluidized catalytic cracking unit (FCCU) Replace or repair slide valves (orifice plates and tongues) FCCU   X     X       Replace or repair spent catalyst slide-valve actuators FCCU   X X X X X     Replace or repair FCCU regenerator cyclones FCCU   X   X X X     Replace or repair FCCU reactor cyclones FCCU   X   X X X     Replace or repair fractionation-tower internals FCCU   X   X X   X   Repair fractionation-tower internals FCCU   X X X X   X   Replace or repair wet-gas compressor FCCU   X   X X       Turnaround Reformer   X         X   Alkylation unit Turnaround Alkylation   X       X     Hydrocracker Turnaround Hydrocracker   X       X     MTBE (methyl tert-butyl ether) unit Turnaround MTBE   X         X   Diesel desulfurization Turnaround with catalyst change Hydrotreatment unit X       X       Coker                   Coke drum replacement Coker       X     X X Crude/coker turnaround Coker     X   X       Sulfur plant SRU thermal-reactor repair SRU   X     X       SRU thermal-reactor replacement SRU       X     X   Turnaround SRU   X         X  

OCR for page 294
New Source Review for Stationary Sources of Air Pollution Activity Unit Estimated Frequency (years) Replacement Cost (% per unit) 1 3-5 5 >5 <5 5-10 10-20 >20 Flare Flare-tip replacement Flare       X   X     Flare knockout drum replacement Flare       X       X Replace flare Flare       X     X   Piping Repair piping recorrosion All   X   X X X     Replace piping recorrosion All   X X X X   X   Heaters/boilers Replace or repair heater tubes All     X X X X     Replace or repair boiler tubes Boilers     X X X X X   Replace burners All       X X X     Steam turbine Steam turbine repairs Turbine   X     X       Steam turbine replacement Turbine       X   X     Storage tanks Repair storage tanks Tank farm     X X X   X   Replace storage tanks Tank farm       X X   X   Replace floating roofs in tanks Tank farm       X X     X Replace floor in tanks Tank farm       X     X   Wastewater systems General maintenance Wastewater X       X       Metallurgical changes Metallurgic changes to accommodate feedstock quality changes       X       X   Instrumentation Replace CEMS         X     X   Repair CEMS       X       X   General instrumentation   X       X       Replace instrumentation         X     X  

OCR for page 294
New Source Review for Stationary Sources of Air Pollution Activity Unit Estimated Frequency (years) Replacement Cost (% per unit) 1 3-5 5 >5 <5 5-10 10-20 >20 Electric substations                   Replace substations         X     X   Repair substations     X     X       Replace transmission lines         X     X   ABBREVIATIONS: CEMS = continuous emission monitoring system; SRU = sulfur recovery unit. SOURCE: National Petrochemical and Refiners Association, unpublished material, 2004.

OCR for page 294
New Source Review for Stationary Sources of Air Pollution TABLE E-3 Pulp and Paper Industry: Repair and Replacement Activities Activity Categorya Estimated Frequency Percent Replacement Cost 1 year 5 years 10 years 20 years <5 5-10 10-20 Boiler used to generate power Repair superheater tie lugs 4 X X     X     Repair superheater steam-cooled spacers 4X       X     X Replace superheater loops 4   X X   X     Replace superheater assemblies 4,7     X X   X   Replace desuperheater liner assembly 4       X X     Replace economizer assemblies 4,7       X   X   Replace generating bank tubes 4,6,7     X X   X   Replace lower-wall tube sections 4,6,7     X X X     Replace lower-wall tube panels 4,6,7       X X     Replace lower furnace 4,6,7       X     X Repair tubular air heaters 4,5 X X X X X     Replace tubular air heaters 4     X X X     Repair refractory 4 X       X     Repair/replace cyclone burners 4,6 X X       X   Clean and scaffold fire side 1,2,4 X       X     Auxiliary equipment for power boiler Repair/rebuild coal pulverizers     4X       X   Repair/rebuild traveling grates     4X   X   X   Repair/rebuild ash-handling system     4X X X   X   Repair/rebuild coal-feeder systems     4X       X   Repair/rebuild boiler safety relief valves 1, 2 X       X     Remove, calibrate, and simulate boiler protective interlock devices 1, 2 X       X    

OCR for page 294
New Source Review for Stationary Sources of Air Pollution Activity Categorya Estimated Frequency Percent Replacement Cost 1 year 5 years 10 years 20 years <5 5-10 10-20 Auxiliary equipment for power boiler Replace, calibrate, and simulate boiler protective interlock devices 1, 3, 4     X   X     Repair/rebuild burner assemblies 4 X       X     Repair/rebuild sootblowers 4 X     X     Repair/rebuild dust collectors 4 X     X     Repair/rebuild precipitators 4 X     X     Repair/rebuild turbine drives 1, 2, 4   X     X     Repair/rebuild FDand ID fans 4   X     X     Upgrade safety systems to revised standards 1, 2, 3     X   X     Replace unsupported control hardware 3, 4     X X   X   Inspect/repair stack 2, 4   X     X     Repair/rebuild ducts and flues 4   X X   X     Building structural repair 4     X X X     Chemical recovery furnace Replace smelt spout tube openings 1, 2, 3, 4, 5   X X   X     Replace lower-wall tube sections 1, 2, 3, 4   X X   X     Replace lower-wall tube panels 1, 2, 3, 4     X X X     Replace lower furnace 1, 2, 3, 4     X X   X   Repair superheater tie lugs 1, 2, 4 X X     X     Repair superheater steam-cooled spacers 1, 2, 4   X X   X     Replace superheater loops 1, 2, 4   X X   X     Replace superheater assemblies 1, 2, 4     X X   X   Replace desuperheater liner assembly 2, 4     X X X     Replace economizer assemblies 1, 2, 4     X X   X  

OCR for page 294
New Source Review for Stationary Sources of Air Pollution Activity Categorya Estimated Frequency Percent Replacement Cost 1 year 5 years 10 years 20 years <5 5-10 10-20 Chemical recovery furnace Replace generating bank tubes 1, 2, 4   X X X   X   Complete NDE 1, 2, 3, 4 X       X     Repair refractory 2, 4 X       X     Clean and scaffold fire side 1, 2, 4 X       X     Chemical recovery furnace auxiliaries Repair/rebuild ash-handling system 4 X X   X     Repair/rebuild green-liquor system 4 X X   X     Repair/rebuild dissolving-tank scrubber system 4 X X   X     Repair/rebuild dissolving tank 3, 4 X X     X     Repair/rebuild black-liquor system 4 X X   X     Repair/rebuild boiler safety relief valves 1, 2, 3 X       X     Remove, calibrate, and simulate boiler protective interlock devices 1, 2, 3 X       X     Repair/rebuild burner assemblies 4 X     X     Repair/rebuild sootblowers 4 X     X     Repair/rebuild direct-contact evaporators 4 X X   X     Rebuild direct-contact evaporators 4   X X   X     Repair steam-coil air heaters 4 X X   X     Replace steam-coil air heaters     X X   X     Repair/rebuild precipitator 4 X   X     X   Repair/rebuild turbine drives 4   X     X     Repair/rebuild forced-draft and induced-draft fans 4   X     X     Upgrade safety systems to revised standards 1, 2, 3   X X   X    

OCR for page 294
New Source Review for Stationary Sources of Air Pollution Activity Categorya Estimated Frequency Percent Replacement Cost 1 year 5 years 10 years 20 years <5 5-10 10-20 Chemical recovery furnace auxiliaries Replace unsupported control hardware 4     X X   X   Inspect/repair stack 4   X     X     Repair/rebuild ducts and flues 4   X     X     Building structural repair 4       X X     Power-plant auxiliary devices Repair/rebuild deaerator 1,3   X X X X     Repair/rebuild demineralizers 4   X X   X     Repair/rebuild boiler-feedwater pumps 4 X X   X     Repair/rebuild air compressors 4 X X   X     Repair/rebuild air dryers 4 X X     X     Repair/rebuild demineralized-water transfer pumps 4 X X   X     Repair/rebuild condensate-transfer pumps 4   X X   X     Repair/rebuild condensate polishers 4   X X   X     Repair/rebuild condensate magnetic filters 4   X X   X     Repair/rebuild water softeners 4   X X   X     Repair/rebuild sand filters 4   X X   X     Repair/rebuild water clarifiers 4   X X   X     Repair/rebuild drive turbines 4 X X   X     Repair/rebuild uninterrupted power supply 4 X X   X     Repair/rebuild station batteries 4 X X   X     Repair/rebuild steam pressure relief valves and desuperheaters 4 X X   X     Repair/rebuild oil storage tanks 1, 4   X X   X    

OCR for page 294
New Source Review for Stationary Sources of Air Pollution Activity Categorya Estimated Frequency Percent Replacement Cost 1 year 5 years 10 years 20 years <5 5-10 10-20 Power-plant auxiliary devices Repair/rebuild woodwaste receiving equipment 4 X X   X     Inspect/repair woodwaste storage equipment 4 X X   X     Repair/rebuild coal receiving equipment 4 X X   X     Repair/rebuild coal storage equipment 4 X X   X     Repair/rebuild natural-gas piping 1, 4   X X   X     Repair/rebuild water storage tanks 4     X X X     aCategory: 1. Required by state regulatory agency or insurance carrier. 2. Required by company or industry standards. 3. Required to maintain safe operation. 4. Required to maintain reliable operation. 5. Required because of design deficiencies. 6. Required because of unforeseen operational problems. 7. Required because of unforeseen mechanical damage. SOURCE: Council of Industrial Boiler Owners, 2004. Reprinted with permission; copyright 2004, American Forest & Paper Association, Inc.