Midterm III Review

1
Midterm III Review

• 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
• SO2
• strategies (avoid formation, throwaway,
  regenerative), wet/dry scrubbing and spray
  drying, mechanisms

2
Midterm II Review (cont.)

• 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, 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
• PART I 40 ( 8 questions) PART II 60 (3
  questions)

3
Example Part I

• 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

• You have just been assigned to design a thermal
  oxidizer to treat VOCs from a paint booth. The
  exhaust air from the booth flows at 1000 acfm at
  400 oF. To effectively reduce emission of VOCs,
  the air must be raised to 1200 oF and held for
  0.8 sec. The burner requires ambient air at a
  mass ratio of 141 (air to fuel gas). Assume the
  heat loss and heat generated from the VOC
  combustion are negligible. (a) Determine the
  flow rate of natural gas needed (in kg/min). (b)
  Size the oxidizer (i.e. diameter and length in m).