How to Control Emissions to The Atmosphere (Wan Mohamad Syameer bin Wan Suhaimi, 25247)

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Hierarchy appropriate for control of
VOC emissions
1) Eliminate or reduce VOC emissions at source.
2) Recover the VOC for reuse.
3) Recover the VOC for treatment and disposal.
4) Treatment and disposal of the VOC-laden gas stream.

Sources of Sulfur Emissions

Sources of NOx (by combustion of fuel)

Emissions from combustion of fuel

Factors for selection of equipment

  • size distribution of particles
  • particle loading
  • gas throughput
  • permissible pressure drop
  • temperature

Gravity Settlers

  • function purely on the basis of density difference and are used to collect coarse particles.


  • Only particles in excess of 100 μm can reasonably


    be removed.

Inertial Collector

  • The particles are given a downward momentum to assist the settling.
  • Only particles in excess of 50μm can be reasonably removed

Cyclones

  • Particle-laden gas enters tangentially and spins downwards and inwards, ultimately leaving the top of the unit.

Scrubbers

  • designed to contact a liquid with the particle-laden gas and entrain the particles with the liquid.
  • can be used to remove gaseous as well as particulate pollutants.

Electrostatic Precipitator

Bag Filters

  • used where collection of fine particles at a high efficiency coupled with a lowpressure drop is necessary.
  • most common method of separating particulate materials from gases
  • cloth or felt filter material is used, which is impervious to the particles.
  • suitable for use in very high dust load conditions..

filters

Control of Solid Particulate Emissions

Methods for VOCs Recovery

  • Condensation
  • Membrane
  • Ad/Absorption

Balancing Line

  • The atmospheric storage tank in is fitted with a vacuum/pressure relief system to guard against overpressure or under pressure of the storage tank.
  • As the atmospheric storage tank is emptied and the road tanker filled, the displaced vapor from the road tanker is pushed back into the atmospheric storage tank
  • In this way, displaced vapor from the road tanker is
    prevented from being released to the atmosphere

balancing line

Methods of VOCs destruction

1) Thermal Oxidation

2) Flares

3) Catalytic Thermal Oxidation

4) Gas Turbines

5) Bioscrubers

6) Biofiltration

Control of VOC Emissions

Chemical production

Smelting process

Fuel processing operations

Combustion of Fuel

Sulfur Minimization

Increase in energy efficiency leading to less fuel burnt

Switch to a fuel with less sulfur

Increase in process yield in chemical production

desulfurizing the fuel prior to combustion

Removal of SO2

Absorption using NaOH

Wet Limestone scrubbing

Wellman-Lord Process

wellman

Control of Sulfur Emissions

Thermal NO

Prompt (rapidly forming)

Fuel NO

NOx Minimization

Increase in energy efficiency leading to less fuel burnt

Switch to a fuel with less nitrogen content

Increase in process yield in chemical production

Minimize NOx formation in combustion process

Control of Oxides of Nitrogen Emissions

Reduction of NOx formation

Reduced air preheat

Flue gas recirculation

Steam Injection

  • CO2
  • SOx
  • NOx
  • Particulate

Minimization of Combustion Products

  • increased
    energy efficiency at the point of use (e.g.better heat integration)
  • increased
    energy efficiency of the utility system (e.g. increased cogeneration)

Control of Combustion Emissions