ACL Ambujanagar

NOx Emission Reduction Possibilities

by

Primary Measures

Thermal Process Technology 1

2

NOx

Impact on Environment

Statutory Limits for Cement Plants

Formation in Cement Plants

Ways to reduce formation

Methods to control the emissions

3

NOx: Impact on Environment

4

NOx Measurement & Reporting

5

Country Limit[mg/Nm3]

Comments

EU 500 / 800 IED (2011) – daily average

Germany 500

200-500

TA Luft (2007) – daily average

17th BImSchV – daily average

Switzerland 800

500 / 450

LRV - daily average

Sectoral NOx Agreement - yearly avg.

USA --

~200 - 400

Limits based on „annual loads“

NESHAP for new/modified kilns –

30 d rolling average

India 1000 Proposed limit (spot measurements)

Thailand 805 Spot measurements

Mexico 940 / 1028-1718 New / existing installations

Brasil 800 / 650 / 495 Existing / new installations

NOx Regulatory Requirements

Holcim Group Average

NOx: ACC – ACL Performance in 2010

Basis: PEP 2010

695

mg

/Nm

3, d

ry a

t 1

0%

O2

CPCB expectation in 2 years

7

NOx Formation in Cement Kilns

RT

-76500

14 e 10 x 2 k N NO O N2

O NO O N 2RT

-6300

9 e 10 x 6.3 k The NOX formation in calciner depends on

- Nitrogen content in the fuel

- O2 level in the firing zone.

- Initial NO concentrations in the combustion gas

- Temperature in firing region

- Volatile content in the fuel

8

NOx Reduction Measures

9

Process Optimization: Primary air and Excess air

NOx Reduction - Primary Measures

10

Process Optimization: Fuel to Calciner

NOx Reduction – Primary Measures

Fuel with high volatile content*

Lump fuel(small portion at kiln inlet)

Low nitrogen fuel

11

Process Optimization: Typical Nitrogen content of the fuels

NOx Reduction – Primary Measures

12

Process Optimization: Burning Zone temperature

NOx Reduction – Primary Measures

Improve process stability

(Kiln feed / fuel feed uniformity, expert optimizer)

Improve kiln feed burnability

(feed mix, fineness)

Avoid over-burning

(strict control of clinker free lime, target >0.8 %)

Optimize burner operation

(Axial / tangential Momentum, fuel fineness)

13

Flue gas re-circulation

NOx Reduction – Primary Measures

14

Low NOx Burner

Burner designed to reduce flame turbulence by delaying the mixing of

fuel and air and by establishing fuel rich zones for initial combustion

NOx Reduction - Primary Measures

15

Low NOx Calciner (Staged combustion)

NOx Reduction – Primary Measures

High Temperature:

Meal split for controlled

hot spot

Reducing Conditions:

Air Split or Calciner

fuel below tertiary air

entry

16

Month average NOx emissions for the plants having CEMS

NOx Reduction – Primary Measures

Low NOx

calciners

Mg

/Nm

3, d

ry a

t 1

0%

O2

17

Limitations of PRIMARY Measures

Primary measures can be applied as long as there is no negative

process, quality or emission impact.

Process optimizations have priority over NOx optimization

Clinker Quality ( Burning under reduced conditions).

NOx Reduction – Primary Measures

18

NOx Reduction – Secondary Measures

Selective Non-Catalytic Reaction (SNCR)

19

NOx Reduction – Secondary Measures

Selective Catalytic Reaction (SCR)

20

0

20

40

60

80

100

Kiln

ope

ratio

n

Burn

er o

ptimiz

atio

n

Fuel m

ix

LowNOx

PC

SNCR

SCR

% N

Ox r

eduction

Effectiveness of NOx reduction measures

21

NOx variations in a day - Normal Operation (13.10.11 00:01 hrs to

14.10.11 00:00 hrs.)

NOx emission at AM 1

~ 200 mg/Nm3

22

NOx variations in a month (October 6 – 31, 2011)

NOx emission at GAJ 1N

Ox, m

g/N

m3, dry

@ 1

0%

O2

23

NOx variations within the kilns (GAJ 1, GAJ2 and AM)

NOx emissions at Ambujanagar

Thank You

24

25

Typical exhaust gas amounts