1. Chapter 12. Air Pollution Control
CIEG 331
Introduction to Environmental Engineering

2. Air Pollution Control
Gaseous
Particulates

3. Gaseous Pollutants
Absorption
Adsorption
Combustion

4. Flue Gas Desulfurization (FGD)
Non-regenerative: non-recovery and reuse of chemical reagents
Regenerative: recovery and reuse of chemical reagents

5. Non-regenerative systems
Chemicals: lime, limestone, caustic soda, soda ash, ammonia
SO2 + CaCO3 ---> CaSO3 + CO2
SO2 + Ca(OH)2 ---> CaSO3 + H2O
CaSO3 + 1/2 O2 ---> CaSO4
Types
Wet
Dry

6. Wet Type
Venturi
Static packed
Moving bed
Tray tower
Spray towers

7. Vertical Venturi Scrubber

8. Packed Bed Scrubber

9. Dry Scrubber System

10. Control Technologies for Nitrogen Oxides
Preventive
minimizing operating temperature
fuel switching
low excess air
flue gas recirculation
lean combustion
staged combustion
low Nox burners
secondary combustion
water/steam injection
Post combustion
selective catalytic reduction
selective non-catalytic reduction
non-selective catalytic reduction

11. Particulate Pollutants
Cyclone
Filter
Liquid scrubbing
Electrostatic precipitation (ESP)

12. Cyclone d0.5 = cut diameter at 50% removalDe L3 D2 L1 L2 Dd H B
d0.5 = cut diameter at 50% removal
m = dynamic viscosity of gas, Pa-s
B = width, m
H = height, m
rp = particle density, kg/m3
Qg = gas flow rate, m3/s
q = effective number of turns

14. For standard Cyclone:
B = 0.25 D2 = 0.13 m
H = 0.5 D2 = 0.25 m
L1 = L2 = 2 D2 = 1 m
Ex. 6-9
Given:
D2 = 0.5 m
Qg = 4 m3/s
T = 25 oC
rp = 800 kg/m3
Q = What is the removal efficiency
for particles with ave
diameter of 10 mm?
h = 0.95
@ d =10 mm

16. Cyclone Installation at Wood Working Plant

17. Air Filtration

18. Case A: Pore blocking
Case B: Pore plugging
Case C1: Pore narrowing
Case C2: Pore narrowing w/lost pore
Case D: Pore bridging

19. Air Filtration Impaction Diffusion Straining (Interception)
Electrostatics

20. Air Filter
High removal efficiency for < 5 mm particles

21. Scrubber
Venturi

22. ESP

23. ESP