aqv91905maziuk

Successful Mitigation of SOSuccessful Mitigation of SO33 By Employing Dry Sorbent By Employing Dry Sorbent

Injection of Trona Injection of Trona

John Maziuk

Solvay Chemicals

Copyright 2005, Solvay America, Inc.Solvay Chemicals, Inc.

Background: SOBackground: SO33 Plume Plume

Fine aerosols scatter light

Low concentrations (10 ppm) visible as blue secondary plume

Does not disperse readily, touch down risk

Plume appearance depends on

Weather: sunny, clouds, rain, etc.

Time of day, angle of sun

Visible to the Public


Background – Plume ProblemBackground – Plume ProblemSCR Additions to Control NOx Emissions resulted

in unintended increase in SO3 generation.

High Sulfur Coal, along with SCRs resulted in a

highly visible secondary plume.


Background – SOBackground – SO33 Sources Sources

SO3 Generation in Steam Generator: 0.1 to 1.5% Oxidation of sulfur during combustion Catalytic oxidation of SO2 by corrosion products

SO3 Generation in SCR Catalytic oxidation of SO2 to SO3

Low conversion catalyst: design conversion 1.3% Regular conversion catalyst: design conversion up to 3%

Function of inlet SO2 concentration, catalyst material, and operating temperature


SOSO33 Formation Formation

0

10

20

30

40

50

60

200 300 400 500 600 700 800 900 1000 1100 1200

Temperature C

SO

2 O

xid

ized

%

Fe2O3

Coal AshCatalytic Oxidation of SO2 to SO3


What is Trona?What is Trona?

Trona is a ore that is mined undergroundTrona is a ore that is mined undergroundTrona is naturally formed sodium Trona is naturally formed sodium

sesquicarbonatesesquicarbonateNaNa22COCO33 NaHCO NaHCO332H2H22OO

Green River formationGreen River formationNumerous beds of TronaNumerous beds of TronaContain billions of tons of TronaContain billions of tons of Trona


Solvay Minerals OperationsSolvay Minerals Operations Solvay Minerals, Inc. Solvay Minerals, Inc.

Currently Mines Currently Mines Trona Ore Trona Ore

at an Approximate at an Approximate Depth of 1500’ Depth of 1500’

(457m)(457m) 12’ (3.67m) Thick and 12’ (3.67m) Thick and

of Very High Qualityof Very High Quality Provide Ore for Many Provide Ore for Many

YearsYears Use Both Longwall Use Both Longwall

Mining and Bore Mining and Bore MinersMiners


Room and Pillar MiningRoom and Pillar Mining


The Surface PlantThe Surface Plant


Trona Dry Sorbent Injection (DSI)Trona Dry Sorbent Injection (DSI)

“Popcorn Effect” ...5 to 20 times the original surface area

2(Na2CO3 NaHCO32H2O)

3Na2 CO3 + CO2 + 5H2O


Trona SEM After CalcinationTrona SEM After Calcination


Trona DSI ChemistryTrona DSI Chemistry

NaNa22COCO33 NaHCO NaHCO332H2H22OO +3HCl +3HCl 3NaCl +4H3NaCl +4H22O + O +

22 COCO2 2

2(Na2(Na22COCO33 NaHCO NaHCO33 2H2H22O) + 3SOO) + 3SO2 2 3Na 3Na22SOSO3 3 + +

44 COCO2 2 + 5H+ 5H22OO

3Na3Na22SOSO3 3 + 1.5O+ 1.5O22 3Na 3Na22SOSO44


Parameters Constraints Parameters Constraints That Affect Sorbent Utilization:That Affect Sorbent Utilization:

Sorbent Injection RateSorbent Injection Rate NSR (Normalized Stoichiometric Ratio)NSR (Normalized Stoichiometric Ratio) Sorbent Particle SizeSorbent Particle Size Sorbent Residence Time In The Flue Gas StreamSorbent Residence Time In The Flue Gas Stream Sorbent Penetration And Mixing Within The Flue Sorbent Penetration And Mixing Within The Flue

Gas Gas Particulate Control Device UsedParticulate Control Device Used Other Acids Other Acids


Impact of Particle Size on T200Impact of Particle Size on T200Performance @325Performance @325ooFF

Effect of Sorbent Size @ NSR 1Source: Solvay Chemicals

0

20

40

60

80

100

11 14 32 65 93

microns

%S

O2

Rem

ova

l


Sodium SOSodium SO33 Reactions Reactions

2 (Na2CO3·NaHCO3·2H2O) + heat 3 Na2CO3 + CO2 + 5 H2O

Na2CO3 + SO3 Na2SO4 + CO2

Na2CO3 + H2O +2SO3 2NaHSO4 + CO2

NaHCO3 + SO3 NaHSO4 + SO3

Na2SO4 + H2SO4 2NaHSO4

2NaHSO4 Na2S2O7


Sodium SOSodium SO33 Reactions (continued) Reactions (continued)


Initial Trial Data with T200 DSIInitial Trial Data with T200 DSIFigure 4: Gavin U-2, SO3 Reduction with Dry Trona Injection Testing

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

Moles Sorbent : Moles SO3

% S

O 3 R

eduction M

easure

d a

t E

SP

Outlet.

SCR O/S

SCR I/S


Cold Side ESP Performance DataCold Side ESP Performance DataFigure 5: Gavin U-2, 2003 ESP Total Current Density vs. Trona Injection Levels

0

5

10

15

20

25

30

35

0 0.5 1 1.5 2 2.5 3

DSI, TPH

Cur

rent

Den

sity

, mA

/ 100

0 S

q. F

t .

Lower BoxesUpper Boxes

All Boxes


Trona Injection LocationTrona Injection Location

FGDESPFurnace

Air

Heater

SCRSTACK

By-Pass Damper

Trona


Hot Side ESP Experience Hot Side ESP Experience @ 800 ppm SO@ 800 ppm SOxx

50%55%60%65%70%75%80%85%90%95%

100%

680 700 720 740 760 780 800 820Temperature F

SO

2 R

em

ov

al

SO2 Removal w/ T200 @ 1.5 NSR


ESP Perf Plates Using Sodium Bicarbonate ESP Perf Plates Using Sodium Bicarbonate >700>700ooFF


Perf Plate Before Hot Side of ESP in Previous Perf Plate Before Hot Side of ESP in Previous Slide After Two Weeks of T200 DSI and still Slide After Two Weeks of T200 DSI and still

“clean as a whistle”“clean as a whistle”


Typical T200 DSI Loading/Storage SystemTypical T200 DSI Loading/Storage System


Proven SOProven SO33 Mitigation Systems Mitigation Systems

Trona Injection At ESP Inlet:

Alone Is Sufficient For SO3 Mitigation, No Visible Plume

Enhances ESP Performance Capital Costs About The Same As Hydrated Lime Operating Costs Less Than Lime No ESP Operational Problems As With Lime


The EndThe End

aqv91905maziuk

Documents

solvay america

underground trona

so3 low conversion catalyst

visible secondary plume

scr catalytic oxidation

design conversion

oxidation of sulfur

manyprovide ore