Electrostatic Science

The Electrostatic Precipitator

What are they?

Electrostatic precipitators are machines that clean air by separating particles using filtration screens and the law of electrostatics. These machines are a leading source of air pollution control, and are being used in multiple industries such as:

-petrochemical and oil refineries

-paper mills

-power generation

-waste inceration

How do they work?

One could sort the process into four stages or sections: the pre-filtering section, the ionizing section, the collection plated section, and the the after-filtration section. Gas flows into the unit and the largest particles are separated in stage 1. Then, in stage 2, the electrodes charge the dust particles, which in stage 3 become attracted to the charged collection plates due tot he law of electrostatics, which states that unlike charges attract. The remaining air is then filtered once more, and is expelled from the apparatus much cleaner than when it entered. This process has become recognized and is commonly used among refineries, power plants, and many other industries.


Below is a video that shows this process in motion. Note each stage in the process.
Electrostatic Precipitator System Working.avi

How is Electrostatics Incorporated?

The image below is a vertical look at stages 2 and 3 of the precipitation process. There is a metal grid (or electrodes) which are negatively charged. When the gas passes through this section, the waste particles become negatively charged. As the air containing these negatively charged particles flows into the third stage and by the collection plates, the particles become attracted to and stick to these collection plates. This happens because the collection plates are positively charged, and as stated in the law of electrostatics, unlike charges attract. After contacting the plates for a while, the particles lose their charge and fall off of the plates. The gas, rid of these waste then particles proceeds into the fourth stage of after-filtration.

Utility and Importance

Electrostatic precipitators are very important in this day-and-age of growing environmental concern because they, on an industrial level, reduce how harmful factory emissions are. This will help both the people, as they will not suffer from as many pollution-related health issues, and the industries, as they will be under less "heat" from the people related to power plant, factory, and other industrial emissions. All in all, this process of cleaning gas is an effective use of electrostatic science that has a strong impact in today's world.
A big-picture of an example of how precipitators are of use. This example is of a factory and how it would use one to purify the exhaust gas to a certain extend before it is expelled.

Citations

"Science: Uses of electrostatics." BBC - GSCE Bitesize. BBC, 2013. Web. Feb.18,2013

<http://www.bbc.co.uk/schools/gcsebitesize/science/add_gateway_pre_2011/radiation/electrostaticsusesrev1.shtml>.


Popular Science Monthly. July 1954. 1954. Google Books. Web. 18 Feb. 2013. http://books.google.ca/books?id=zSADAAAAMBAJ&pg=PA70&source=gbs_ge_summary_r&redir_esc=y#v=onepage&q&f=true>.


IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997). XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8. doi:10.1351/goldbook.

<http://goldbook.iupac.org/E02028.html>.

(note, above citation was listed as “cite as” on the website)


"Electrostatic Precipitator KnowledgeBase." Neundorfer Particulate Knowledge. Neundorfer, Web. 18 Feb. 2013. <http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx#itp>.


Mill, George S., and W O. Miligan. "Electrostatic precipitator." Mc-Graw Hill Education , 2012. AcessScience. Web. 18 Feb. 2013. <http://bb.hts.on.ca/webapps/portal/frameset.jsp?tab_tab_group_id=_2_1&url=%2Fwebapps%2Fblackboard%2Fexecute%2Flauncher%3Ftype%3DCourse%26id%3D_101_1%26url%3D>


"How Electrostatic Precipitators Work." Trion Air Purification Systems. Trion IAQ, 2011. Web. 18 Feb. 2013. <http://www.trioniaq.com/industrial/index.aspx?prod=how_electrostatic_precipitators_work>.



"Electrostatic Precipitators." Hamon Research-Cottrell Inc. Hamon Research-Cottrell, Inc., Web. 18 Feb. 2013. <http://www.hamonusa.com/hamonresearchcottrell/products/esp>.


โอโจ้ ปานสนาม “Electrostatic Precipitator System Working.avi” Youtube. Web. 1 Mar. 2012.