1. Module 2 Particles

2. MCEN 4131/5131 2 What are we doing in class today? Preliminaries –Grad students HW 2 add 3.17 and 5.16 –Assignment for Thurs find a recent newspaper article that discusses air pollution newspaper –How to use handouts to help with reading/quizzes –Valmont Power Plant tour, Apr 6 10am and 1pm Review Module 1 - Overview Particles Tools, Examples

3. MCEN 4131/5131 3 Module 1 Educational Objectives Name the NAAQS criteria pollutants and the standard values for PM2.5, CO, O3 (Table 1.1, p. 22)NAAQS Define Prevention of Significant Deterioration (PSD) (p. 18) Describe and apply the New Source Performance Standards (NSPSs) (p. 22) Apply the ideal gas law (p. 31) Convert from ppm to  g  m 3 (p. 32) Describe the major air pollutants of concern, their major sources and why they are of concern (PM, SO2, NOx, VOCs and photochemical oxidants, CO) (p. 46-56) Solve material balance problems (p. 75) Review

4. MCEN 4131/5131 4 Module 2 Educational Objectives Size of particles that are most responsible for visibility reduction (p. 48) Aerodynamic diameter (p. 102, 114) Particle size distributions (p. 105) Device removal efficiencies are a function of particle size (p. 106) Terminal settling velocity (p. 3.20) Difference between impaction, interception, diffusion (p. 116) Particle penetration of a device (p. 118) Learning Objectives for Today

5. MCEN 4131/5131 5 Particulate Matter (PM) Particles found in the air, including dust, dirt, soot, smoke, and liquid droplets Particles can be suspended in the air for long periods of time Some particles are large or dark enough to be seen as soot or smoke Others are so small that individually they can only be detected with an electron microscope Intro

6. MCEN 4131/5131 6 Primary PM Intro

7. MCEN 4131/5131 7 Secondary PM Intro

8. MCEN 4131/5131 8 Visibility Reduction One of the major impacts of particles in the atmosphere Other effects - health, damaging of surfaces, global climate change Learning Objectives Visibility Aerodynamic diameter Size distributions Removal efficiencies Settling velocity Impact/intercept/diffuse Penetration

9. MCEN 4131/5131 9 Clicker Question What are the sizes of particles most responsible for visibility reduction? a. 300 to 800 nm b. 0.1 to 5  m c. 2.5 to 10  m Learning Objectives Visibility Aerodynamic diameter Size distributions Removal efficiencies Settling velocity Impact/intercept/diffuse Penetration

10. MCEN 4131/5131 10 Clicker Question - Extra Credit An object is visible to the eye because it contrasts with its background. The apparent contrast of an object can be described mathematically as ___________ function of the distance between the observer and the object. a. A Linear b. An Exponential c. A Logarithmic d. Don’t know Learning Objectives Visibility Aerodynamic diameter Size distributions Removal efficiencies Settling velocity Impact/intercept/diffuse Penetration

11. MCEN 4131/5131 11 Aerodynamic Diameter Learning Objectives Visibility Aerodynamic diameter Size distributions Removal efficiencies Settling velocity Impact/intercept/diffuse Penetration

12. MCEN 4131/5131 12 Aerodynamic Diameter Solid sphere  = 2 Hollow sphere  = 0.5 Irregular shape  = 2.4 D a = 2  m Particles that appear to have different physical sizes and shapes can have the same aerodynamic diameter Learning Objectives Visibility Aerodynamic diameter Size distributions Removal efficiencies Settling velocity Impact/intercept/diffuse Penetration

13. MCEN 4131/5131 13 Clicker Question True or False: The aerodynamic diameter of a specific particle is the diameter of a particle with unit density that will settle at the same rate as the particle in question a. True b. False Learning Objectives Visibility Aerodynamic diameter Size distributions Removal efficiencies Settling velocity Impact/intercept/diffuse Penetration

14. MCEN 4131/5131 14 Particle Mass Distribution Total mass = 920 mg Learning Objectives Visibility Aerodynamic diameter Size distributions Removal efficiencies Settling velocity Impact/intercept/diffuse Penetration

15. MCEN 4131/5131 15 Mass Fraction in Size Range Learning Objectives Visibility Aerodynamic diameter Size distributions Removal efficiencies Settling velocity Impact/intercept/diffuse Penetration Mass fraction in this size range = 179.5 / 920 = 19.5%Mass fraction in this size range = 368 / 920 = 40%

16. MCEN 4131/5131 16 Device Removal Efficiency Learning Objectives Visibility Aerodynamic diameter Size distributions Removal efficiencies Settling velocity Impact/intercept/diffuse Penetration

17. MCEN 4131/5131 17 Overall Efficiency  = Learning Objectives Visibility Aerodynamic diameter Size distributions Removal efficiencies Settling velocity Impact/intercept/diffuse Penetration

18. MCEN 4131/5131 18 Gravity Terminal Settling Velocity The velocity of a falling particle when the gravitational force downward is balanced by the air resistance (or drag) force upward Drag Force Buoyancy Learning Objectives Visibility Aerodynamic diameter Size distributions Removal efficiencies Settling velocity Impact/intercept/diffuse Penetration

19. MCEN 4131/5131 19 Clicker Question The terminal settling velocity is proportional to the following parameter squared: a. Cunningham slip factor b. particle density c. particle diameter d. Viscosity e. Don’t know Learning Objectives Visibility Aerodynamic diameter Size distributions Removal efficiencies Settling velocity Impact/intercept/diffuse Penetration

20. MCEN 4131/5131 20 Learning Objectives Visibility Aerodynamic diameter Size distributions Removal efficiencies Settling velocity Impact/intercept/diffuse Penetration

21. MCEN 4131/5131 21 Learning Objectives Visibility Aerodynamic diameter Size distributions Removal efficiencies Settling velocity Impact/intercept/diffuse Penetration

22. MCEN 4131/5131 22 Clicker Question The smaller grey particle is collected on the larger blue object by what mechanism? a. Interception b. Diffusion c. Impaction Learning Objectives Visibility Aerodynamic diameter Size distributions Removal efficiencies Settling velocity Impact/intercept/diffuse Penetration

23. MCEN 4131/5131 23 Diffusion Learning Objectives Visibility Aerodynamic diameter Size distributions Removal efficiencies Settling velocity Impact/intercept/diffuse Penetration

24. MCEN 4131/5131 24 Diffusion Learning Objectives Visibility Aerodynamic diameter Size distributions Removal efficiencies Settling velocity Impact/intercept/diffuse Penetration

25. MCEN 4131/5131 25 Diffusion Learning Objectives Visibility Aerodynamic diameter Size distributions Removal efficiencies Settling velocity Impact/intercept/diffuse Penetration

26. MCEN 4131/5131 26 Diffusion Learning Objectives Visibility Aerodynamic diameter Size distributions Removal efficiencies Settling velocity Impact/intercept/diffuse Penetration

27. MCEN 4131/5131 27 Impaction Learning Objectives Visibility Aerodynamic diameter Size distributions Removal efficiencies Settling velocity Impact/intercept/diffuse Penetration

28. MCEN 4131/5131 28 Impaction Learning Objectives Visibility Aerodynamic diameter Size distributions Removal efficiencies Settling velocity Impact/intercept/diffuse Penetration

29. MCEN 4131/5131 29 Impaction Learning Objectives Visibility Aerodynamic diameter Size distributions Removal efficiencies Settling velocity Impact/intercept/diffuse Penetration

30. MCEN 4131/5131 30 Learning Objectives Visibility Aerodynamic diameter Size distributions Removal efficiencies Settling velocity Impact/intercept/diffuse Penetration …Or overall collection efficiency

31. MCEN 4131/5131 31 Learning Objectives Visibility Aerodynamic diameter Size distributions Removal efficiencies Settling velocity Impact/intercept/diffuse Penetration For the above system, the overall penetration Pt O can be determined using the following equation (choose one): a. c. b.