Comparison of Sodium Bicarbonate and 

for Multi-pollutant Control

Yougen Kong

Stan Carpenter

Solvay Chemicals Inc.

ELECTRIC POWER 2010

Baltimore, Maryland

May 18-20, 2010
Outline

• Dry Injection System

• Trona and Sodium Bicarbonate

• Which Sorbent to Use?

• Summary
Economizer

Air Heater

Boiler

Air

Trona/

Sodium

Bicarbonate

ESP/

Bag Hous

Dry Injection System

300 600 oF oF

> 800 oF
T

r

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a

A

p

p

l

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c

a

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H

i

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9

6

5: T

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o

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a

d

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s

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t in

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tio

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(

D

SI)

f

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mitig

a

tio

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a

t

C

alif

o

r

nia

E

dis

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•

1

9

7

0

s: P

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blic

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•

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d

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y: M

a

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y lo

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sin

g

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S

O

2, S

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3

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H

Cl.
Sodium Bicarbonate Application His

• Widely used in Europe to remove over 95% of 

99% of HCl.

• Has been used in limited applications at powe

• Have not achieved wide applications in North A

due to:

– Product availability

– High cost

• Solvay Chemicals has started to produce low-

sodium bicarbonate with a patented process in 

River, Wyoming

– Capacity: 125,000 tons/year.

– Phase II: Another 125,000 tons/year
Trona Sodium Bicarb

Calcination at > 275 oF
Chemical Reactions

Na2SO4, NaCl and NaF are collected in fly as

• Trona Calcination

2(Na2CO3·NaHCO3· 2H2O) (s) + heat →

3Na2CO3(s) + 5H2O(g) + CO2(g)

• Sodium Bicarbonate Calcination

2NaHCO3 (s) + heat → Na2CO3(s) + H2O(g

• Acid Neutralization Reactions

– Na2CO3 + SO2 + 1/2O2 → Na2SO4 + CO2– Na2CO3 + SO3 → Na2SO4 + CO2– Na2CO3 + 2HCl → 2NaCl + H2O + CO2– Na2CO3 + 2HF → 2NaF + H2O + CO2
Economizer

Air Heater

Boiler

Air

Silo

Mill

Sodium

Bicarbonate

ESP

Bag H

Handling Systems for Trona and Sodium Bica

Silo

Trona or

Pre-milled Sodium

Bicarbonate
SO2 Removal (%) Up to 90% > 95%

- Baghouses

SO2 Removal (%) Up to 80% > 90%

- ESP

275 ~ 1500 275 ~ 1500 o

Flue Gas Temperature oF

Range for injection

N NaHCO3 a2CO3.NaHCO3 Formula .2H2O

Sorbent CostFree-flowing bulk

density (lb/ft3)

Particle Size: d50 (μm)

Low Medium49 63~ 30 μm ~ 100 μm

Sodium Bi

SOLVAir® 

Trona

SOLVAir® Select 200

* Must be milled before injection

** Performance of sodium bicarbonate may briefly dip at ar
Which Sodium Sorbent to Us

Factors to consider when making choic• Required SO2 removal Rate

– More economical to use sodium bicarbonate for 

removal requirements.

• ESP or baghouse

– Sodium bicarbonate is economically favored ove

ESP. Both are very effective with baghouses.

• Disposal cost of fly ash

– Sodium bicarbonate results in less unused sorbe

favored if the fly ash disposal cost is high.

– Sodium bicarbonate results in lower sodium in fl

• Trona is ready-to-use and sodium bicarbona

to be milled.

– Pre-milled sodium bicarbonate is available at hig
Performance Comparison: Hot-side E

0

102030405060708090

100

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 

NSR

SO

2

RemovalRate(%)

Trona

Pre-milled

Sodium Bicarbonate

• Boiler: 100 MW burning low-sulfur coal (SO2: 1.2 lb/MM

• Sorbent injected upstream of hot-side ESP @ 650 oF.
Performance Comparison - Cold-side 

• Boiler: 350 MW burning CAPP coal (sulfur content: 

• Sorbent injected at 650 oF upstream of air preheate

0

102030405060708090

100

0 0.5 1 1.5 2 

NSR

SO

2

RemovalRate(%)

Pre-milled

Sodium Bicarbonate

Trona
Performance Comparison - Baghou

0

10203040506070

0.0 0.2 0.4 0.6 0.8 1.0 1

NSR

SO

2

RemovalRate(%)

SBC

Trona

Unmilled SBC

• Boiler: 100 MW burning low-sulfur coal (SO2: 0.59 lb/M

• Sorbent injected upstream of bag house @ 290 oF.
Economical Analysis

Case I• 100 MW

• Sulfur content of coal:

1.2 lb/MMBTU SO2

• Required SO2 removal

rate: 80%

• ESP

• Capacity factor: 75%

• Annual Operation Cost*:

– Trona: $5,000,000

– Sodium Bicarbonate**:

$3,200,000 + milling cost

Choice: Sodium Bicarbonate

Case II• 100 MW• Sulfur content 

0.59 lb/MMBTU 

• Required SO2 R

Rate: 40%

• Baghouse

• Capacity factor

• Annual Operati

– Trona: $670,00

– Sodium Bicarb

$550,000 + mil

Choice: Trona

* Operation cost includes sorbent cost and disposal cost of unreacted s

**Mills needed for sodium bicarbonate. Cost of mills not included.
Effects on HCl and SO3

• Trona and sodium bicarbonate are 

effective in mitigation of HCl.

• While sodium bicarbonate is as ef

in mitigating SO3 as trona, some s

bicarbonate will be consumed by S

due to its higher reactivity with SO

• Generally speaking trona is more

economical than sodium bicarbon

mitigating HCl and SO3.
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For more information, please visit www.sol

Thanks!

Questions?