study guide

EHST 3600: Exam 2 Study Guide The exam will have questions of the following types: multiple choice, true or false, short answers, and problem solving. Please review all lecture materials, especially the topics I mention every “Last Session Review” and “Session Summary”. Pay extra attention on the following: Meteorology, part 2

 Wind velocity profile - factors

 Planetary boundary layer – within; above; relation to terrain roughness

 Maximum mixing depth – how to measure; Rawinsonde; day vs night

 Horizontal dispersion – wind speed, wind direction o Wind rose – definition; interpretation; frequency by wind speed and direction

 Atmospheric turbulence – thermal vs mechanical

 Plume behavior – factors

 Urban microclimate o Urban heat island effect – definition; how communities are affected; effects of paved surfaces

Dispersion of pollutants in the atmosphere

 Dispersion from sources into atmosphere – factors

 Settling or terminal velocity – definition; relation to particle size and ground-level concentration

 Plume downwash – determine possibility; gas exit velocity vs 

 Stack height (actual, effective, reduced), plume rise – definition Particulate Control

 Definition of particulate types

 Collection efficiency – definition (overall, fractional); relationship with particle size

 Particle diameter – how to characterize (SA, volume, behavior) o Aerodynamic diameter – definition

 Settling or terminal velocity – definition

 Emission reduction vs process and system control

 Hood and duct design o Control velocity – definition; factors o Effect of flanges o Null point - definition

 Particulate collection mechanisms

 Particulate control equipment – factors needed to be known for proper choice o Gravity settling chamber – mechanism, advantages, disadvantages o Cyclone separators - mechanism o Wet collectors – mechanism; disadvantages; types (venturi scrubber) o Air filtration – mechanism

 Fabric filter – factors affecting choice of fabric type; relationship between particulate accumulation, collection/ removal efficiency, pressure drop; advantages and disadvantages

 Bag house - definition o Electrostatic precipitators – mechanism; advantages

 Steps in collection mechanism – gas ionization  removal of deposited PM

 Dust electrical resistivity General control of gases and vapors

 Adsorption – definition; mechanism; 3 uses o 2 types of adsorption – physical adsorption vs chemisorption (characteristics of each) o Examples of adsorbents – activated carbon, silica gel, etc. (characteristics and uses of each)

 Good properties of an adsorbent o Adsorption wave – definition; description o Adsorption zone - definition; description o Breakthrough point – definition o Types of regeneration – cold vs hot (characteristics of each, advantages, disadvantages)

 Absorption – definition; differentiate with adsorption o Importance of gas solubility o Use of packing materials in packed towers

 Incineration – definition; advantages; disadvantages o 3 components of combustion process – uses of each o Excess air – definition; effects on CO emissions o 4 types of combustion products – oxidized products of C-C and C-H bonds, of fuel impurities, etc.;

specific examples for each type o 3 types of incineration

 Direct flame – description; disadvantages; characteristics of flare  Recuperative – description; primary vs secondary energy recovery  Catalytic – description; purpose of the use of catalyst

o Incineration of hazardous wastes – primary goals  Definition of hazardous waste by EPA  4 type of hazardous waste incinerators – liquid waste incinerator, rotary kiln/afterburner,

etc. (characteristics of each)  Most controversial emissions from MSW incinerators

Good luck!