Environmental engineering papet

1. Air Pollution Control
Mr OA Olawuni
September 2023

2. Introduction
Air
Pollution
Presence of substances in
concentrations that make the air
harmful or dangerous to breathe.
The substances can cause damage to
animals, plants and properties.
Problem – Air pollution control
negatively affects production/
industrial development.
2

3. Types of pollutants
Substances that cause air pollution are particulate and gaseous.
Types of
pollutants
Particulates
Dust (1 – 1000 μm) – solid particles from processes such as
grinding, crushing and blasting
Fumes (0.03 – 0.3 μm) – fine solid particles that condense from
vapours of solid material.
Smoke (0.5 – 1 μm) – unburnt carbon from incomplete combustion.
Fly-ash (1 – 1000 μm) – non-combustible material – inorganic .
Mist (0.07 - 10 μm) – from condensation of liquid vapours. It can
form fog.
Spray (10 – 1000 μm) – from atomization of liquids.
Gases
Carbon monoxide
Nitrogen dioxide
Ozone
Sulphur dioxide 3

4. Pollutants can also be classified as Organic or Inorganic.
Other classification used is Primary and Secondary.
• Primary – Produced at source e.g. NO from combustion.
• Secondary – Produced later from primary pollutants e.g. NO2 from NO.
Types of pollutants cont’d
Organic
Biological origin
Pollens
Microscopic algae
Spores
Bacteria
Viruses
Alive or recently died
Inorganic
Carbon monoxide
Nitrogen dioxide
Ozone
Sulphur dioxide
4

5. Pollutant Limits - USA
5

6. Effect of CO
Pollution –
Hemoglobin
Chemistry
Carbon monoxide is absorbed much faster than Oxygen, according to
Equation 12-1
• The binding of carbon monoxide with haemoglobin reduces the oxygen-carrying
capacity of the blood and impairs the release of oxygen from haemoglobin to
extravascular tissues.
• Main cause of tissue hypoxia produced by carbon monoxide at low exposure
levels.
• Hemoglobin binds carbon monoxide 200 to 300 times more than with oxygen,
resulting in the formation of carboxyhemoglobin and preventing the binding of
oxygen to hemoglobin due to the competition of the same binding sites.
https://www.euro.who.int/__data/assets/pdf_file/0020/123059/AQG2ndEd_5_5carbonmonoxide.PDF
https://www.ncbi.nlm.nih.gov/books/NBK539815/
6

7. 7

8. Sources of Pollutants
All pollutants can be
classified according to their
respective sources as shown
in Table 12-3.
Miscellaneous sources
include wildfire and
agricultural burning.
8

9. Air Pollution
Control
• Definition: Measures to meet certain
emission standards.
• It can be divided into Particulate
Control and Gaseous Control.
• Particulate Control Measures:
Gravitational Settling, Centrifugal
Settling, Electrostatic Precipitators,
Baghouse filters etc.
9

10. Gravitational Settling
The design is based on
wastewater treatment
except the medium is air
in this case.
Equations 12-3 through
12-8 (next slide) are used
to determine the settling
velocity and particle
diameter.
10

11. Gravitational Settling
vh = flow-through velocity
R = fractional removal of solids
vo = terminal velocity of solids removed 100%
d = average diameter of the equivalent spherical particle
dp = average “diameter” of the particle
d = diameter of particle that can be removed 100%
v = Q/WL = terminal velocity of particle (dia. d)
11

12. 12

13. 13

14. 14

15. 𝑣 = 161.552 ×
𝑑𝑝
𝐶𝐷
𝑅𝑒 = 6.84 × 104
× 𝑑𝑝 × 𝑣
𝐶𝐷 =
24
𝑅𝑒
dp CD Guess v Re CD
5.00E-06 3.77E+04 1.86E-03 6.36E-04 3.77E+04
15

16. 16

17. 17

18. Particulate Control – Centrifugal
Settling
18

19. Particulate
Control –
Centrifugal
Settling
19

20. g = centrifugal acceleration; vt = tangential velocity
Average cross-section area of flow of outer vortex
Using v = Q/Ah
Overflow area of settling zone (average of outside and
inside lateral areas of the outer-vortex settling chamber)
Overflow velocity
(Use CD=24/Re and solve for d). Diameter of
solids that are removed 100%
20

21. 21

22. Particulate Control – Electrostatic
Precipitation
22

23. 23

24. Force of attraction
Electric field: Force/charge
Sphere of radius R
24

25. Charge induced by potential difference for electrode
with diameter d
m=
𝜋𝑑3𝜌𝑝
6
Drift or electric wind velocity
Lateral areas of the tubes; D = tubes diameter
25

26. Overflow velocity (Tubes) 𝐶𝐷 =
24
𝑅𝑒
d=diameter of particles that are 100% removed (Tubes)
Overflow velocity (Plates)
d=diameter of particles that are 100% removed (Plates)
Average E between electrodes
Power consumption
26

27. Particulate
Control –
Baghouse
filters
27

28. Particulate Control
– Baghouse filters
28

29. 29

30. 30

31. Particulate
Control –
Scrubbers
31

32. 32

33. Gaseous
Polluters –
Activated
Carbon
Adsorption
33

34. Gaseous
Polluters –
Packed
Tower
Absorber
34

35. Gaseous Polluters – Thermal
Incinerator
35

36. [1] A. Devi, S. Bajar, H. Kour, R. Kothari, D. Pant, and A. Singh, "Lignocellulosic Biomass Valorization for Bioethanol Production: a Circular Bioeconomy Approach,"
Bioenergy Res, vol. 15, no. 4, pp. 1820–1841, Dec. 2022.
Corncobs Burning of
Corncobs
Greenhouse
Emission
Global
Warming
Fig. 1. Environmental Impact of Corncobs Management Through Conventional Method
36
My Doctoral Research
Background/Motivation of the Study
• Waste biomass is generated in large quantities [1].
• Improper waste management severely affects the environment and human health (Fig. 1).
• Air pollution
• Cause respiratory disease in humans

37. 37
CAGR – Compound Annual Growth Rate is the rate at which an investment grows.
[2]https://africabusinesscommunities.com/news/south-africa-sasol-achieves-beneficial-
operation-of-second-lake-charles-chemicals-project-production-facility
[3]https://en.wikipedia.org/wiki/Hydrodesulfurization
Fig. 3. Hydrodesulfurization Unit in a Refinery[3]
Fig. 2. SASOL Facility with Hydrodesulfurization[2]
Hydrodesulphurization of Liquid
Fuel
• Hydrodesulphurization is one of the most important
processes in the oil refining industry and it is a
catalytic chemical process used to reduce pollutants
in the fraction of petroleum distillates.

38. Fig. 4. Schematic Representation for Production of Biomass-based Nanocellulose Crystals for Adsorptive Desulphurization
[4] L. Huang et al., "Silver-Nanocellulose Composite Used as SERS Substrate for Detecting Carbendazim," Nanomaterials, vol. 9, no. 3, pp. 355, Mar. 2019.
[5] O. A. Olawuni, O. O. Sadare, and K. Moothi, "Optimization of liquid hot water pretreatment for extraction of nanocellulose crystal from South African waste
corncobs," Chem Eng Commun, pp. 1–14, Jun. 2023. 38
Valorization of Waste Biomass for Environmental Sustainability
• Biomass-based nanocellulose has been widely investigated in recent years [4,5].
• Biomass-based nanocellulose crystals as shown in Fig. 4.

39. Artificial Intelligence Desulphurized Fuel
Sulphur Rich
Fuel
Nanotechnology
+ Transportation
Power Generation
Fig. 5. Relationship between nanotechnology and artificial intelligence for desulphurization
[6] Onu, C. E., Nweke, C. N., & Nwabanne, J. T. (2022). Modeling of thermo-chemical pretreatment of yam peel substrate for biogas energy
production: RSM, ANN, and ANFIS comparative approach. Applied Surface Science Advances, 11.
[7] Sacha, G. M., & Varona, P. (2013). Artificial intelligence in nanotechnology. Nanotechnology, 24(45), 452002. 39
Application of Fourth Industrial Revolution to Desulphurization of
Liquid Fuels
• Nanotechnology integrates the principles of chemistry, physics, and engineering for different purposes,
while artificial intelligence uses the human neural system to predict, optimize, and model the outcomes of
scientific processes [6,7].

40. 40
[8] R. Rashid et al., “A state-of-the-art review on wastewater treatment techniques: the effectiveness of adsorption method,” Environmental Science and Pollution Research, vol. 28, no. 8, pp. 9050–
9066, Feb. 2021.
[9] S. Bradie et al., Desulfurization of Liquid Hydrocarbon Fuels with Microporous and Mesoporous Materials: Metal-Organic Frameworks, Zeolites, and Mesoporous Silicas. Ind. Eng. Chem. Res., Vol.
58 (42), pp. 19322-19352, Sept. 2019.
[10] O.O. Sadare, et al., Removal of Sulfur ( e.g. DBT ) from Petroleum Distillates using Activated Carbon in a Continuous Packed-bed Adsorption Column. Proceedings of WCECS 2018, vol. II, Oct.
2018. USA
Fig. 7. Schematic representation of Adsorptive
Desulphurization of Liquid Fuels [10]
Fig. 6. Desulphurization of Liquid Fuels with Microporous and
Mesoporous Materials [9]
Adsorptive Desulphurization of Liquid Fuel
• Adsorptive desulphurization is cost effective at ambient temperature and pressure.
• The process occurs by moving sulphur organic compounds from liquid fuels to an adsorbent via physicochemical
interaction with an efficiency of about 99% [8].