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C: \Users\Gary\Desktop\Methodology for Calculating FEGT for Domtar.doc

1165 A LLGOOD R OAD  S UITE 6  M ARIETTA

, GA 30062  P HONE : (770) 977

- 4248  F AX : (770) 977-2832  E- MAIL : iae@iaeinc.com 

# Methodology f or Calculating Furnace Exit Gas Temperature

The following fuel heating values were used:

 Bark @ 50% moisture: 4,200 Btu/lb

 Coal: 11,884 Btu/lb

 Tire Derived Fuel (TDF): 16,513 Btu/lb

 Natural Gas: 1,000 Btu/scf

For grate fired fuels (bark & TDF) an equivalent flat projected furnace wall area (Sc ) of 10,884 ft2 ( Sc 4 

## ) was used. For wall fired fuels (coal & natural gas) two different Sc values were used depending on the number of burner levels in service. When the coal flow was calculated to fall below 10 t/h, the bottom row of coal burners was turned off.

T he Sc used when coal flow is calculated to be 10 t/h or more was 10,539 ft2 (Sc 3 

## )

. The Sc used when coal flow is calculated to be under 10 t/h wa s 9,509 ft2 (Sc 2 

## ).

The heat input from each fuel was calculated by multiplying the fuel flow by the corresponding heating value. The furnace heat release rate was obtained by dividing the fuel heat inputs by the corresponding Sc . Two empirical curves were used for determining the furnace exit gas temperature (FEGT). One is for grate fired fuels and one is for pulverized coal fired from a single wall. The curves were converted into mathematical equations in the spreadsheet, and the weighted average between the two curves, based on the ratio of grate fired heat input versus wall fired heat input, is displayed as the FEGT.

Methodology for Calculating Absorptive Surface Area in Domtar PB#2

Empirical Data:

 Form P- 3 Manufacturer’s Data Report for Water -tube Boilers, Superheaters, Waterwalls, and Economizers; 114-0253 Babcock & Wilcox Company 1975

 Sectional Side View at “E–E” DWG. 36057F

 Front and Rear Wall dimension of 19’

- 11” centerline to c enterline per

Domtar

Protocols:

 2- 1/2” tubes on 3” centerline to centerline spacing with 1⁄2” web converted to 4.427” flat projected surface measurement

 Corrected absorptive surface area (Sc) is calculated from five (5) feet below

center line of burner for c onditions Sc 1 

## , Sc 2 

## , and Sc 3

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C: \Users\Gary\Desktop\Methodology for Calculating FEGT for Domtar.doc

1165 A LLGOOD R OAD  S UITE 6  M ARIETTA

, GA 30062  P HONE : (770) 977

- 4248  F AX : (770) 977-2832  E- MAIL : iae@iaeinc.com 

##  Sc 4 

## is calculated from centerline of headers above the grate to the roof in front of the superheater for front wall and sidewalls, and from centerline of header above grate to apex of neck on back wall

 A correction factor for dirty furnace walls for pulverized coal firing was used on the portion of the furnace affected by the burners on Sc 4



## Respectfully Submitted September 9, 2014, by:

Gerald R. (Gary) Elliott Principal Engineer

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C:\Users\showard\AppData\Local\Microsoft\Windows\Temporary Internet Files\Content.Outlook\AUGXGWWV\Observations of Charted Stea m Rates and Furnace Exit Gas Temperature.doc

1165 A LLGOOD R OAD  S UITE 6  M ARIETTA

, GA 30062  P HONE : (770) 977-4248  F AX : (770) 977-2832  E- MAIL : iae@iaeinc.com 

## Observations of Charted Steam Rates and Furnace Exit Gas Temperature (FEGT)

Based upon empirical data received from Domt ar on Power Boiler #2 (PB2) in the form

of a spreadsheet recording data on an h ourly basis from 0600 7/14/2014 to 0600

7/26/2014, PB2 Fuel Analysis Cu rrent Operation Summer, calc ulated absorptive surface

area in the boiler, and custom heat transfer to furnace curves, an estimated FEGT for

this period was calculated. International Applied Engineering (I AE) has charted the

measured Steam Rate and calculated FEGT ov er the 12-day period covered by the

data supplied. Overlaying th e charted data is a band representing the range of

temperature (1700-1800°F) where an SNCR technology could be expected to reach

40% denitrification efficiency at the current boiler conditions of 10% excess O2 and

typical fuel blend at that corresponding steam demand rate, provided the Normalized

Stoichiometric Ratio (NSR) was appropriate for the fuels mixture input and the ammonia

or urea application was effective.

 There is a direct positive relationship between Steam Demand and FEGT

 Only a Steam Demand above 350 klb/hr will generate FEGT in the range for

optimal Denitrification Efficiency

 At no time during the 12-day period studied did conditions exist for longer than

four (4) hours continuously that would satisf y Denitrification Efficiency equal to or

above 40%

 Steam Demand fluctuates fr om 10 klb/hr to as much as 50 klb/hr on at least an

hourly basis (minimum recorded period)

 There are nine (9) recorded periods of at least one (1) hour when expected

Denitrification Efficiency should equal or exceed 40%

 These periods total twenty (20) hours over the 12-day period (288 continuous

hours) and equal less than 7% of the evaluation period1,0001,1001,2001,3001,4001,5001,6001,7001,8001,9002,0000.0050.00100.00150.00200.00250.00300.00350.00400.00450.00500.007/12/20140:00 7/14/20140:00 7/16/20140:00 7/18/20140:00 7/20/20140:00 7/22/20140:00 7/24/20140:00 7/26/20140:00 7/28/20140:00 FEGT (F)

Steam Rate (klb/hr)DomtarPB#2SteamRates(klb/hr)&FEGT(F)SteamFEGTSNCR>40%DenitrificationEfficiency@10%O2level