Electrostatics

Electrostatic Precipitator

What are Electrostatic Precipitators?

The electrostatic precipitator was invented in 1910 by Frederick Cottrell. (Science In Context) Since then, electrostatic precipitators have become very successful and are now used by many factories. Electrostatic precipitators are air cleaners that remove small pollutant particles out of the smoke and gasses that factories and smokestacks produce. Electrostatic precipitators are the machines factories use to decrease their contribution to air pollution. There are also small home precipitators, which remove irritants, pollutants, and allergens from inside air conditioning and heating systems in people's houses. Electrostatic precipitators have become very fundamental to the air pollution reduction initiative, and have also become machines that are part of our daily lives.

How Does It or What Makes It Work?

An electrostatic precipitator is a machine that puts the Laws of Electrostatics to use. The machine is based off the principles that opposite charges attract, neutral and charged objects attract, and neutral objects don't attract each other. It also depends on the concept that when a charged object comes in contact with a grounded conductor, the charged object becomes neutral. Electrostatic precipitators have five main components. There is the power supply or source, the ionizing wires, the metal collection plates, the hoppers, and the gas/smoke that travels through the machine. The laws of Electrostatics are essential to the operation of this machine.

The Process

After the polluted gas enters the precipitator, the particles in the gas become positively charged by the ionizing wire. This wire has a strong positive charge on it due to the power supply giving it that charge. The positively charged pollutant particles induce charge separation in the metal collection plates. Because opposite charges attract, the electrons in the plates are attracted to the now positively charged particles. The particles then collide with the grounded collection plates. But remember, when a charged object touches a grounded conductor, the charged object becomes neutral; therefore the pollutant particles become neutral again. This means that the particles are no longer attracted to the collection plates, as neutral objects don't attract each other. The particles drop into the hoppers, which are the bins located at the bottom of the precipitator that the pollutant particles are collected in. The pollutant particles are then disposed of in an environmentally friendly way.

Why Is It Important?

Electrostatic precipitators are important because they help us to reduce our environmental footprint. They make the amounts of air pollution factories produce much lower. This is important because the amount of air pollution we create as a population is increasing, and has become a health risk. The precipitators are making the factories eco-friendly, as well as making the environment safer. They are important in home environments because because these machines remove allergens and irritants from the air. The population of people with asthma is increasing, and precipitators make it more difficult for the asthma to act up.

Pros & Cons

Electrostatic precipitators are very useful but they also have some drawbacks. Electrostatic precipitators are used industrially and remove over 99% of the particles from stack gas emissions associated with the burning of coal and oil; that is to say they are very effective.(OpenStax College) On the other hand, they require a lot of maintenance. The hoppers need to be emptied very frequently, as after the pollutant particles drop into the hoppers, they build up very quickly. They also require a large space to be most efficient.


Citations

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Blake, Leesa . "10.3 Charges at Work." Trans. Array Using an Electric Charge to Reduce Pollution and Waste. Mc Graw-Hill Ryerson. 9th ed. Canada: Diane Wyman, Print.


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"Clearing the Air About Electronic Air Cleaners." World Book Science Year. 2009. eLibrary. Web. 12 Feb. 2013.


Congressional Testimony. TECHNOLOGIES FOR REDUCING GREENHOUSE GAS EMISSIONS:JOHN FEES. Federal Document Clearing House, , 09 May. 2007. eLibrary. Web. 12 Feb. 2013.


Environmental Protection Agency. "Particulates - Electrostatic Precipitators (ESPs)."EPA. Environmental Protection Agency, 29 Jan. 2010. Web. 20 Feb. 2013. <http://www.epa.gov/eogapti1/course422/ce6a1.html>.


"Frederick Gardner Cottrell." World of Invention. Gale, 2006. Science In Context. Web. 15 Feb. 2013.


"How Can We Solve the Energy Crisis? (1973)." World Book Year Books. 2009. eLibrary. Web. 12 Feb. 2013.


Modern Alchemy Air Purifiers. "Electrostatic Air Cleaners." Electrostatic Air Cleaners. Modern Alchemy Air Purifiers, n.d. Web. 20 Feb. 2013. <http://www.modernalchemyair.com/technology/electrostatic/>.


OpenStax College. "Applications of Electrostatics." Connexions. Rice University, 17 Jan. 2012. Web. 18 Feb. 2013. <http://cnx.org/content/m42329/latest/?collection=col11406/latest>.


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