Preview: Midterm I

1
Preview Midterm I

• Introduction
• Regulations, design criteria, combined efficiency
• Gas Properties
• Unit, ideal gas law, vapor pressure, solubility,
  energy balance, psychrometric chart, cooling
• Particle Characteristics
• PSD, representative size, log-normal, relaxation
  time/stopping distance, settling velocity,
  aerodynamic diameter, mechanical mobility,
  Settling Chamber deign, diffusion diffusivity
• Cyclone
• Mechanism, collection efficiency, cut size,
  effective size range of collection, pressure
  drop, standard designs, cost

2

• ESP
• charging mechanisms (number of charges),
  electrical mobility, drift velocity,
  Deutsch-Anderson Eq., SCA, resistivity, types of
  ESP, arrangement
• Filtration
• collection mechanisms, single fiber collection
  efficiency, total filter efficiency, pressure
  drop, filter drag, multi-compartment operation,
  respiratory deposition

3
Example Part I (5 Q, 20)

• Miss Steelhead is in charge of choosing a system
  for cooling exhaust from a steam-electricity
  co-generation plant in Las Vegas. You are a
  technical advisor working for Ironman Heat
  Exchanger. Give two reasons to Miss Steelhead
  why her plant should use air dilution instead of
  or water injection or a heat exchanger.

4
Example Part II (5 Q, 80)

• An ESP consists of 3 stages, each with 5 plates,
  in a series. Dirty gas entering the ESP is
  uniformly distributed in all rows. The gas
  leaving the previous stage is fully mixed before
  entering the next stage. All 3 stages have the
  same electrical field strength. Eastern coal
  containing 3 S is used as the fuel. The stack
  temperature is 140 oC. The gas flow rate is 800
  m3/min. Plate dimension is 3 m ? 4 m. (a)
  Determine the effective drift velocity of the
  incoming particles entering the first stage. (b)
  Calculate the efficiency at each stage and the
  total efficiency. (c) If one electrode at each
  stage fails, calculate the total efficiency.