CE 3231 - Introduction to Environmental Engineering and Science

Readings for This Class:

5.5-5.6

Ohio Northern University

Introduction Chemistry, Microbiology & Material Balance Water & Air Pollution Env Risk Management

Air Pollution Control TechnologiesAs long as we burn fossil fuels, we will need treatment control technologies in order to attempt to offset the negative releases of pollution to the environment. This lecture presents and introduction to the most common air pollution control technologies.

Atmospheric Dispersion Modeling

Lecture 28Air Pollution Control Technologies

(Air Quality III)

Air Pollution Control Device

Topics Covered Include: Reason for Air Pollution Control Devices Types of Controls Description of Common Controls

C(x,0) dependent on Q

Air pollution control devices seek to limit Q

Q = emission rate of pollutants, g/s

Air Pollution Control Technology

1. Precombustion 2. Combustion 3. Post Combustion

http://www.energyeducation.tx.gov/

Air Pollution Control Technology

1. Precombustion

American Coal Foundation (http://www.teachcoal.org/aboutcoal/articles/coalreserves.html)http://online.wsj.com/article/SB124414770220386457.html

Air Pollution Control Technology

1. Precombustion

http://www.instituteforenergyresearch.org/states/ohio/

Air Pollution Control Technology

2. Combustion

http://geosci.uchicago.edu/~moyer/GEOS24705/Images/CoalPowerPlant_TVA.gif

Boiler Technology

Air Pollution Control Technology

2. Combustion

<http://www.britannica.com/EBchecked/media/113942/Schematic-diagram-of-a-fluidized-bed-combustion-boiler>.

Fluidized Bed Combustion

- still boiling water, but feed (coal) is mixed with limestone to remove SOx during the process (90% removal of Sox).

- Operates at lower temperature (~800 C) than conventional boiler and reduces NOx formation due to more efficient combustion

Air Pollution Control Technology

3. Post- Combustion

• Desulfurization• Electrostatic precipitators (dry and wet)• Bag house filters• Cyclone collectors

sulfur

particulates

Post Combustion

• Desulfurization– Wet scrubbing

• Alkaline dissolved in water• Sprayed alkali water droplets

absorb sulfur

Simplification:

H2O + CaCO3 (solid) + SO2 (gas) → CaSO3 (solid) + CO2 (gas) + H+

http://en.wikipedia.org/wiki/File:Flue_gas_desulfurization_unit_EN.svg

Post Combustion

• Electrostatic Precipitator– Voltage applied across plates

• Attracts ions of opposite charge

http://en.wikipedia.org/wiki/Electrostatic_precipitator

Post Combustion

• Bag house filter

– Dry filtration of gas

• Air filters through fabric or other media

http://www.tethis-lab.com/anima/pp-baghouse-filter.html

Post Combustion

• Cyclone

– Dry filtration of gas

• Dust spun out of air

http://www.dustcollectorscyclone.com/

Air Control Technologies

– Even if we can remove the NOx, SOx, and particulates, we still have to worry about CO2

http://www.metoffice.gov.uk/education/secondary/students/smog.html

Clean Coal Technologies Parts 1 & 2

Air Pollution Control Devices Video