KingSteamGeneratorUpgrades&Maint

8/13/2019 KingSteamGeneratorUpgrades&Maint

1/26

Steam Generator

Upgrades &Maintenance

Presented by:

David King, Manager

Steam Generation Equipment

Engineering

APP Site Visit

October 30 November 4, 2006


2/26

2

Topics of Discussion

Steam Generator Upgrades & Maintenance Steam flow balancing

Air heater baskets & seals

Component replacement upgrades (material & design)

Online detonation cleaning Water Cannons/HydroJets

Acoustic leak detection

Weld overlay & coatings

Balanced draft conversion on FGD units Nose installation on 800 MW units

Boiler tube failure program

4thgeneration low NOx burners


3/26

3

Topics of Discussion

Fuel Considerations Matching steam generator design with fuel

characteristics

Benefits of washing coal

Coal additive injection


4/26

4

Steam Flow Balancing

Aptech TubMod Analysis at Glen Lyn Unit 6 The unit experienced high temperature variations

across the boiler, caused by tube circuit design andgas temperature/flow imbalances.

TubMod analysis was performed to improve thetemperature profile and extend the life of thesuperheater tubing.

Through the TubMod process, temperatureimbalances can be corrected by redistributing the

steam flow. The result is an evening out of the tubemetal temperature across the superheater elements,and a reduction in the temperature on the elementsoperating excessively hot.


5/26

5

Steam Flow Balancing


6/26

6

Air Heater Baskets

Modifications are necessary to accommodate highsulfur fuel switch programs and SCR retrofits.

Considerations to address high sulfur applications: Increased attention to exit gas temperatures being maintained

above the acid dew point.

Modifications to address SCR retrofits: Redesign of the heat transfer surface arrangement.

3 layers reduced to 2 to envelope the ABS formation temperaturewithin an area that can be cleaned with conventional sootblowing.

The use of closed channel elements to better contain and focusthe cleaning media to the areas of likely deposition.

The utilization of multimedia blowers to facilitate both conventionalon-line cleaning, and off-line washing.


7/26

7

Air Heater Baskets

Open Channel Surface Closed Channel Surface

Cleaning energy dissipates rapidly Cleaning media diverted around deposits Requires higher pressure for effective

cleaning Higher risk of element damage from

cleaning

Each channel acts like a closed pipe Cleaning energy cannot divert around

deposits Deposits are readily removed, at lower

pressures Lower risk of element damage from

cleaning

Cleaning Media Discharge

Cleaning Media Inlet

ALSTOM Power Inc. Air Preheater Company


8/26

8

Air Heater Seals

Paragon air heater seal installation at Welsh Unit 3 Air heater leakage across air heater radial seals can

average as much as 15 to 20%.

The air heater leakage results in excess FD and ID fan

motor amps, with the recognizance that the fan motorsare one of the largest auxiliary power consumers in theplant.

Reducing air heater leakage will show immediate heatrate benefits.

Welsh Unit 3 saw a 30% reduction in ID fan amps afterthe installation of the Paragon Airheater Technologiesradial and circumferential/bypass seals.


9/26

9

Air Heater Seals

The Paragon DuraMax radial seals incorporate unique, self-adjusting bellows that ensure positive contact with the sealingsurfaces.

The Paragon DuraFlex high-performance circumferential andbypass seals use a patented revolutionary interlocking design

which reduces the air gaps.


10/26

10

Component Upgrades

Total Platen Replacement Projects Upgrade tube material to all stainless steel vs. in-kind

material selection with croloy and stainless steelmaterial transitions.

Improves the boilers slag shedding capability. Expands the types of coal a particular unit can burn.

Stainless Steel Weld Overlay for Shielding Use SS weld overlay on new boiler tube components

in lieu of tube shields at sootblower locations. Spiral weld overlay has higher upfront cost, but minimal

future O&M costs to maintain.

AEP has some spiral weld overlay tubing in sootblower laneswith 10 years of service and no reported issues.


11/26

11

Component Upgrades

New Alignment and Attachment Designs


12/26

12

Online Detonation Cleaning

Pratt & Whitney SHOCKSystem EconomizerCleaning at Rockport Unit 2 Provides non-line-of-sight cleaning of tube bundles to remove

bridging and platenization.

Ash Piles Extend Beyond Hangers

North Wall

Lower EconomizerBundle

Problem: Excessive Ash Piles andBridging Cause Delta P andHeat Transfer Impact

Spatial Constraints PreventInstallation of ConventionalSootblowers

Middle EconomizerBundle


13/26

13


Ash Pile Accumulation Over Nine

Months of Continuous Boiler Operation

First Two Ash Piles Removed After Two

Days of SHOCKSystem Operation

Before SHOCKSystem After SHOCKSystem

SHOCK Blasts

SHOCK Blasts

BEFORE AFTER


14/26

14


Five CombustorEconomizerCleaner at

Rockport Unit 2


15/26

15


Rockport Unit 2 Economizer Cleaning InstallationFive Days of Intensive SHOCKSystem Operation

Temperature of Gas to Airheater Decreased By 30F

Weight of Ash Removed 240,000 Lbs

Effective Heat Transfer Increased By 10%

Delta T Across Economizer Increased By 15F

Temperature of Gas from Airheater Decreased By 15F


16/26

16

Water Cannons/HydroJets

Provides intelligent real-time cleaning of furnacesusing water cleaning hardware and a closed-loopcontrol system that utilizes sensors and software. Displaces conventional wall blowers or water lances as the best

available technology for furnace cleaning. Uses cross-furnace cleaning where a controlled water jet is

transmitted across the firebox to the opposite or adjacent walls.

Water Cannon HydroJet
http://www.clydebergemann.com/content_manager/go/ID/22222/dbc/c31f41946dbdf26e3ff7e75e804d1b0bhttp://www.clydebergemann.com/content_manager/go/ID/22222/dbc/c31f41946dbdf26e3ff7e75e804d1b0b


17/26

17

Water Cannons/HydroJets

Gavin Unit 2 Water Cannon Performance Testing

Heat Rate Decreased by 25 BTU/kwh

NOx Emissions Reduction of 0.04 lb/MMBTU

Furnace Exit Gas Temperature Decreased by 112F

S02 to S03 Conversion Reduction of 8-10%


18/26

18

Acoustic Leak Detection

Acoustic leak detection system at Gavin Unit 1 & 2 Consists of 30 remote acoustic sensors attached to membrane ofexterior furnace walls and penthouse roof.

Ethernet daisy-chain provides communication to control room werecentral computer is located.

Information is processed, filters applied (sootblowers, furnacepenetration seal air, etc.) and information is displayed on operatorPC screen.

Alarms are established for each sensor and refined as leaks aredetected.

Acceptance and reliance on acoustic leak detection hasreduced forced outage durations from weeks to days.

Provides better indication of tube leak than any othermethod, including older style acoustic leak systems andwater loss tests.


19/26

19

Acoustic Leak Detection

Leak detection screen and alarm indicationthreshold at 92 dB.

Gavin sensor layout along with HP heater screen

which also have 1 acoustic leak detector per heater.


20/26

20

Weld Overlay & Coatings

Efforts to minimize NOx production have led to increasesin furnace waterwall wastage, which has necessitatedfurnace corrosion protection.

To combat high levels of corrosion, AEP currentlyreviewing various furnace protections including: Weld overlay Metal spray coatings

Ceramic coatings

The industry is working to optimize the choice of overlay

and metal spray materials. Computer Modeling and/or thickness surveys are utilizedto identify the areas needing protection.

The overlay and metal spray processes have beenautomated by the vendors.


21/26

21

Balanced Draft Conversion

Converting positive pressure units to balanced draftoperation while retrofitting FGDs. Improves the work environment of the boiler house, thus increasing

productivity and equipment longevity.

Reduces the likelihood of fugitive emissions occurrences due to

casing leaks. Utilizes multi-speed motors on existing FD fans and the

application of variable pitch axial ID fans. Provides the additional head to overcome the added resistance of

the FGD.

Optimizes unit efficiency over the load range and provides improvedunit control.

FD fan controls volume flow while ID fan maintains furnace pressure.

Requires upgrading steam generators to accommodate theextremes of balanced draft operation.


22/26

22

Furnace Nose Installation

Furnace nose installation on AEPs 800 MW unitscompleted in conjunction with FGD retrofit.

Reduces the peak temperatures leaving the

furnace, thereby reducing the slagging potentialwith higher sulfur coals.

Serves to improve mixing and heat absorption in thefurnace.

Spreads the flue gas flow out over the leading edgesurface of the pendants.

Installed a 10 foot long nose in a 39 x 80 furnace.


23/26

23

Furnace Nose Installation

Mitchell Unit 1&2 CFD Modeling Expected Performance

Boiler Efficiency Improved by 0.07%

Superheater Heat Absorption Increased by 15%

Furnace Exit Gas Temperature Decreased by 17F

Coal Consumption Reduced by 0.12%

Loss on Ignition Reduced by 0.05%

Aperture Floor Velocity Reduced from 200 fps to 56 fps


24/26

24

Boiler Tube Failure Program

Provides centralized boiler tube failure data andmetallurgical analysis results. Makes for easy access to information/data for capital

replacement justification purposes or O&M repairs.

Centralized boiler tube failure tracking helps to alertother like series units of potential related tube failuremechanisms or issues.

All tube failures are routed through corporate

engineering. Based on visual review, the failuresamples may be forwarded to AEPs internal labfor further metallurgical and root cause analysis.


25/26

25

4thGen Low NOx Burners

Existing Low NOx Burners 25 hot tips/burner fires per year

NOx emissions 0.75 lb/MMBTU

Projected 135 hot tips/year with future coal (highsulfur and slagging)

New Low NOx Burners

0 hot tips to date

NOx emissions 0.48 lb/MMBTU Potential urea cost reduction of $2,500,000/year @

$350/dry ton urea (365 day ozone control)


26/26

26

Documents

KingSteamGeneratorUpgrades&Maint