AIR POLLUTION

INDUSTRIAL NOx REMOVAL

What is Air Pollution?The Importance Of Air Other planets have sunlight, but the Earth is the only planet we know

that has air and water. Without air and water, the Earth would be unable to sustain life.

A diverse community of plant and animal life has thrived on this planet for millions of years, sustained by the sun and supported by the soil, water and air.

Definition Of Air Pollution Air pollution occurs when the air contains gases, dust, fumes or odour

in harmful amounts. That is, amounts which could be harmful to the health or comfort of humans and animals or which could cause damage to plants and materials.

The substances that cause air pollution are called pollutants. Pollutants that are pumped into our atmosphere and directly pollute the air are called primary pollutants. Primary pollutant examples include carbon monoxide from car exhausts and sulfur dioxide from the combustion of coal.

Further pollution can arise if primary pollutants in the atmosphere undergo chemical reactions. The resulting compounds are called secondary pollutants. Photochemical smog is an example of this.

The NO molecule;

The NO molecule was first discovered by Joseph Priestley in 1772, the same personwho previously had discovered the oxygen molecule . Under atmosphericconditions, NO appears as a clear, colourless gas. NO is present in the atmosphere asa result of human activities such as the emission of waste gas from combustionprocesses using fossil fuels, burning biomass, but also from natural sources like soilemissions. NO plays an important role in the formation of photochemical smogand acid rain.

NO is not only a dangerous pollutant, but it is also an essential molecule for livingspecies. NO is produced in nature by animal and plant cells from the amino acid, LarginineIn 1992, NO was named molecule of the year by the journal Science andin 1998, the Nobel Prize in Medicine was awarded for the discovery of the effects ofNO in living organisms. Due to its small dimensions, the molecule is able to passthrough cell membranes and it can serve as a signalling agent .For example, inmammals, NO helps to maintain blood pressure within certain limits by dilating bloodvessels and it plays a role in the regulation of the immune system. It also plays a rolein controlling the penile erection, by taking part in the enzymatic pathway responsiblefor the relaxation of blood vessels. As a matter of fact, Viagra® amplifies the NOeffect in this process .Inside the brain, NO can contribute to the formation ofmemory and it plays a role in the communication between neurones. Recently, ithas been discovered that NO is able to block a protein involved in Parkinson.s diseaseproviding new pathways for treatment methodologies.

NOx sources

Natural Sources - Lighting Bolts:A natural source of nitrogen oxides occurs from a lightning stroke. The

very high temperature in the vicinity of a lightning bolt causes the gases oxygen and nitrogen in the air to react to form nitric oxide.

N2 + O2 --> NO

The nitric oxide very quickly reacts with more oxygen to form nitrogen dioxide.

NO + O2 --> NO2

Both of the nitrogen compounds are known collectively as nitrogen oxides or NOx.

Human Sources of Nitrogen Oxides:At normal temperatures the oxygen and nitrogen gases do not react

together. In the presence of very high temperatures nitrogen and oxygen do react together to form nitric oxide.

These conditions are found in the combustion of coal and oil at electric power plants, and also during the combustion of gasoline in automobiles. Both of these sources contribute about equally to the formation of nitrogen oxides.

In areas of high automobile traffic, such as in large cities, the amount of nitrogen oxides emitted into the atmosphere can be quite significant. In the Los Angeles area, the main source of acid rain is from automobiles.

In certain national parks such as Yosemite and Sequoia, automobile traffic is banned to limit the amount of air pollution damage to the trees and plants. This also has the effect of reducing the visual smog in the air.

WHY SHOULD WE CONTROL NOx?

NOx represent a family of seven compounds. Actually, EPA regulates only nitrogen dioxide (NO2) as a surrogate for this family of compounds because it is the most prevalent form of Nox in the atmosphere that is generated by anthropogenic (human) activities. NO2 is not only an important air pollutant by itself, but also reacts in the atmosphere to form ozone (O3) and acid rain. It is important to note that the ozone that we want to minimize is tropospheric ozone; that is, ozone in the ambient air that we breathe. We are not talking about stratospheric ozone in the upper atmosphere that we cannot breathe. Stratospheric ozone protects us and the troposphere from ionizing radiation coming from the sun.

AQAST research highlightsNASA Aura Ozone Monitoring Instrument shows

decreasing NO2 between 2005 and 2010 by Bryan Duncan

1. Yeniköy

2. Yeni Kaptan

3. İzmit-Anıtpark

4. Köseköy

5. Körfez-Tüpraş

6. Körfez-İgsaş

7. Körfez-Petkim

8. Değirmendere

9. Sopalı

10. Yuvam

Removal Techniques

prevention of NOx formation during the combustion process;

removal of NOx in the flue gas (end-of-pipe) 1) Nitrogen Oxide Removal During Combustion Staged Combustion Fludized Bed Combustion2) Nitrogen Oxide Removal After Combustion NOx prevention End of pipe NOx removal technologies: SCR and SNCR NO removal using micro-organisms NO removal using wet absorption with metal chelates

Staged Combustion

Fludized Bed Combustion

1) NOx Prevention

2) Schematic representation of the SCR process. NH3 liquid is vaporized before being mixed with

the flue gas

3) NO Removal Using Micro-Organisms

4) NO Removal Using Wet Absorption with Metal Chelates

Çimento, Kireç veMagnezyum Oksit İmalat SanayilerindeMevcut En İyi Teknikler Referans Dokümanı

Mayıs 2010

http://www.tcma.org.tr/images/file/IPPC.pdf

BEST AVAILABLE TECHNIQUES (BAT) FOR NOx FOR EXISTING BASELOAD

UK COAL UNITS >300MW

http://www.environmentagency.gov.uk/static/documents/Business/UKTWG13_Final_NOx_baseload_coal.pdf

Improvement Options NOx

http://www.environmentagency.gov.uk/static/documents/Business/UKTWG13_Final_NOx_baseload_coal.pdf

Limit değerler, değerlendirme ve uyarı eşikleri

The Emission Values of Solid Fuel

www.mevzuat.gov.tr

The Emission Values of Liquid Fuel

www.mevzuat.gov.tr

The Emission Values of Gas Fuel

www.mevzuat.gov.tr

EPA has established National Ambient Air Quality Standards (NAAQS) for NO2 and tropospheric ozone. The NAAQS define levels of air quality that are necessary, with a reasonable margin of safety, to protect public health (primary standard) and public welfare (secondary standard) from any known or anticipated adverse effects of pollution. The primary and secondary standard for NO2 is 0.053 parts per million (ppm) (100 micrograms per cubic meter), annual arithmetic mean concentration.

Tropospheric ozone has been and continues to be a significant air pollution problem in the United States and is the primary constituent of smog. Large portions of the country do not meet the ozone NAAQS and thereby expose large segments of the population to unhealthy levels of ozone in the air. NO2 reacts in the presence of air and ultraviolet light (UV) in sunlight to form ozone and nitric oxide (NO). The NO then reacts with free radicals in the atmosphere, which are also created by the UV acting on volatile organic compounds (VOC). The free radicals then recycle NO to NO2. In this way, each molecule of NO can produce ozone multiple times.40 This will continue until the VOC are reduced to short chains of carbon compounds that cease to be photo reactive (a reaction caused by light). A VOC molecule can usually do this about 5 times.

In addition to the NO2 and Ozone NAAQS concerns, NOx and sulfur oxides (SOx) in the2 atmosphere are captured by moisture to form acid rain. Acid rain, along with cloud and dry deposition, severely affects certain ecosystems and directly affects some segments of our economy. All of these facts indicate an obvious need to reduce NOx emissions. However, to successfully do so, we must understand the generation and control of the NOx family of air pollutants.

The technique which SANTA uses

REFERENCES www.mevzuat.gov.tr/Metin.Aspx?MevzuatKod=7.5.1402

7&MevzuatIliski=0&sourceXmlSearch=b%C3%BCy%C3%BCk%20yakma%20tesisleri

http://www.mevzuat.gov.tr/Metin.Aspx?MevzuatKod=7.5.12188&MevzuatIliski=0&sourceXmlSearch=hava kalitesi

http://www.santa.com.tr/YONERGE/NOx-emisyonu.pdf http://www.epa.gov/ttncatc1/dir1/fnoxdoc.pdf http://www.environment-agency.gov.uk/static/

documents/Business/UKTWG13_Final_NOx_baseload_coal.pdf

http://www.environment-agency.gov.uk/static/documents/Business/UKTWG6_Final_NOx_midmerit.pdf

http://www.tcma.org.tr/images/file/IPPC.pdf http://web.deu.edu.tr/fmd/s18/18-08.pdf http://www.oecd.org/environment/indicators-modelling-

outlooks/31558547.pdf

Thanks for Listening Zeynep AKTOSUN

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