Midterm II Review

1
Midterm II Review

• Particulate Scrubber
• types of scrubber, collection mechanisms,
  collection efficiency (spray chamber, venturi
  scrubber), contact power (pressure drop)
• Adsorption Bed
• categorization, isotherm (Langmuir, Freundlich),
  breakthrough curve, regeneration, pressure drop,
  maximum/minimum bed depth
• Absorption Tower
• gas/liquid phase controlled mass transfer,
  equilibrium/operating line, mass balance, liquid
  flow rate/tower diameter/tower height, HTU/NTU
  (physical meaning), pressure drop
• Incineration
• stoichiometry, reaction kinetics, mass balance
  energy balance (required heat rate, available
  heat), required fuel rate, incinerator size,
  reaction rate mass transfer rate

2
Midterm II Review

• SO2
• strategies (avoid formation, throwaway,
  regenerative), wet/dry scrubbing and spray
  drying, mechanisms
• NOx
• Combustion modification (temperature, time), flue
  gas treatment (SCR/NCR)
• Mobile sources
• types of sources, impact, emission standards,
  engine operation (4-stroke, 2-stroke, diesel),
  fuel (gasoline, diesel, octane rating,
  alternatives-E85, bio-diesel, H2), transportation
  policy/regulation, catalytic converter (2-way,
  3-way, temperature and air/fuel ratio), hybrid
  cars, fuel cell H2 (production/storage)
• Comparison and Selection of appropriate control
  devices for a given scenario

3
Example Part I (7 questions, 30)

• Hydrogen has been proposed to be an alternative
  fuel to gasoline for automobiles. The
  feasibility depends on hydrogen production,
  on-board storage and conversion. Briefly
  describe how hydrogen can be produced, stored for
  on-board usage and converted into mechanical
  power.

4
Example Part II (4 questions, 70)

• You have just been assigned to design a thermal
  oxidizer to treat VOCs from a citrus processing
  plant in South Florida. The exhaust air from the
  citrus processing flows at 750 m3/min at 100 oC.
  To effectively reduce emission of VOCs, the air
  must be raised to 1000 oC. The burner requires
  ambient air at 25 oC at a mass ratio of 141 (air
  to fuel gas). Natural gas is used as the fuel
  and it is supplied at 25 oC. Assume 10 heat
  loss. Consider heat generated from the
  combustion of VOCs are negligible. Determine the
  mass flow rate of natural gas needed (in kg/min).