User:Milton Beychok/Sandbox: Difference between revisions

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[[Image:Gas Flare.jpg|right|thumb|200px|{{#ifexist:Template:Gas Flare.jpg/credit|{{Gas Flare.jpg/credit}}<br/>|}}A gas flare as used in the petroleum industry.]]


A '''flare stack''' or '''gas flare''' is an elevated vertical vent pipe used in [[Petroleum refining processes|petroleum refineries]], [[chemical plant]]s and [[petrochemical plant]]s, oil and gas drilling sites, [[Natural gas processing|natural gas processing plants]], and [[landfill]]s used for burning off unusable  waste gas or flammable [[gas]] and [[liquid]]s released by pressure [[relief valve]]s during unplanned over-pressuring of plant equipment.<ref>{{cite book|author=John J McKetta, Editor|title=Encyclopedia of Chemical Processing and Design|publisher=Marcel Dekker|year=1985|pages=144|id=ISBN 0-8247-2491-7}}</ref><ref>{{cite book|author=Milton R. Beychok|title=[[Fundamentals of Stack Gas Dispersion]]|edition=Fourth edition|publisher=self-published |year=2005|id=ISBN 0-9644588-0-2}} [http://www.air-dispersion.com www.air-dispersion.com] See Chapter 11, ''Flare Stack Plume Rise''.</ref><ref>[http://aiche.confex.com/aiche/s06/techprogram/P40539.HTM A Proposed Comprehensive Model for Elevated Flare Flames and Plumes], David Shore, Flaregas Corporation, [[AIChE]] 40th Loss Prevention Symposium, April 2006.</ref> 
==The purpose of flare stacks==
In petroleum refineries, chemical plants and petrochemical plants, oil and gas drilling sites,and natural gas processing plants, the main purpose of a flare stack is that of safety by protecting  [[pressure vessels]] or pipes from over-pressuring due to unplanned upsets.
In [[landfills]], the primary purpose of this device is to vent and/or burn waste gas which results from the decomposition of materials in the landfill.
==How flare stacks work==
Whenever plant equipment items are over-pressured, the [[pressure relief valve]]s provided as essential safety devices on the equipment automatically releases gases (and sometimes liquids as well) which are routed through large [[piping]] runs called ''flare headers'' to the flare stacks. The released gases and/or liquids are [[Combustion|burned]] as they exit the flare stacks. The size and brightness of the resulting flame depends upon how much flammable material was released.
Steam is very often injected into the flame to reduce the formation of black smoke. In order to keep the flare system functional, a small amount of gas is continuously burned, like a [[pilot light]], so that the system is always ready for its primary purpose as an over-pressure safety system.
==Environmental impacts==
The flaring and venting of [[assocated gas]] from oil drilling sites is a significant source of [[carbon dioxide]] (CO<sub>2</sub>) emissions. The amount of such emissions has declined from a peak of about 110×10<sup>6</sup> metric tons in the 1970s to 40×10<sup>6</sup> metric tons in 2005, a decrease of about 64 percent.<ref name=Lulea>[http://www.ltu.se/polopoly_fs/1.5035!gas%20flaring%20report%20-%20final.pdf Gas Flaring Emission Contributes to Global Warming] Lulea University of Technology (Sweden) and Institut National des Sciences Appliquées de Lyon (France)</ref>
The [[World Bank]] estimates that 150 billion cubic meters of raw [[natural gas]] are flared.<ref>[http://web.worldbank.org/WBSITE/EXTERNAL/TOPICS/EXTOGMC/EXTGGFR/0,,menuPK:578075~pagePK:64168427~piPK:64168435~theSitePK:578069,00.html The World Bank]</ref>  This flaring is highly concentrated: 10 countries account for 75% of emissions, and twenty for 90%.<ref name=Lulea/> The largest flaring operations occur in the [[Niger Delta]] region of [[Nigeria]]. The leading contributors to gas flaring are (in declining order): [[Nigeria]], [[Russia]], [[Iran]], [[Iraq]],  [[Angola]], [[Qatar]], [[Algeria]], [[Venezuela]], [[Equatorial Guinea]] and  [[Indonesia]].<ref name=Lulea/>
== References ==
<references/>
==See also==
*[[Flue gas stacks]]
*[[Relief valve]]

Revision as of 01:30, 14 August 2008

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