LO-NOx burner 4376793 219024492 2008-06-13T06:17:49Z 121.243.119.85 [[Image:low-nox-burner.gif|thumb|right|One of John Joyce's early sketches of the Low NOx burner ]] A '''LO NOx burner''' is a type of burners typically used in utilty boilers to produce steam and electricity. ==Background== [[Image:W201.gif|thumb|right|John Joyce the inventor of the LO-NOx burner at [[Australian Gas Association]] Conference in the early 1990's]] === The first discovery === Around 1986 John Joyce (of [[Bowin Cars]] fame), an influential Australian inventor, first learned about [[oxides of nitrogen]] (NO<sub>x</sub>) and their role in the production of [[smog]] and [[acid rain]]. His first introduction to the complexities of the subject was brought about by the work of Fred Barnes and Dr John Bromley from the state Energy Commission of Western Australia.<ref>J Joyce; ''In Search of The Low NO<sub>x</sub>'' Australian Gas Association Conference [[August 5[[[[1991]] Burner</ref> The vast majority of the research and development stretching back over twenty years was about large scale industrial burners and complex mechanisms which, in the end, did not produce what one would consider low NO<sub>x</sub> (2 ng/J or ~ 4 ppm at 0% O<sub>2</sub> on dry basis)<ref>Australian Patent Document No.: AU-B-16047/92</ref>. In fact at that time, 15 ng/J NO<sub>2</sub> appears to have been considered low NO<sub>2</sub>. The one clear message that did flow through all the mass of information he studied, was the effect of [[temperature]] on the formation of NO<sub>x</sub>. === Need is the "Mother of Invention" === In the late 1980s, Health and Environment Authorities in [[Australia]] raised concerns about the [[indoor air quality]] and the extent that particularly older style [[unflued gas heater]]s were contributing to higher than acceptable levels of [[nitrogen dioxide]] (NO<sub>2</sub>). Consequently in 1989 the [[New South Wales]] Department of School Education initiated an extensive investigation of nitrogen dioxide in schools throughout New South Wales. As an interim measure the Health Authorities advised that a level of 0.3 [[parts per million|ppm]] NO<sub>2</sub> should become the upper limit for classrooms<ref>S McPhail and A Betts; ''Flueless gas heaters in NSW Government Schools'' Proc 11th Clean Air Conf, Clean Air Soc Aust and New Zealand,5-10 July 1992,Brisbane</ref>. The [[Australian Gas Association]] in turn reduced the indoor [[emission]] rate of NO<sub>2</sub> for unflued gas heaters from 15 to 5 ng/J and this remains the current limit<ref>AS 4553-2000 (AG 103-2000) Gas space heating appliances</ref>. The New South Wales government, through the Public Works Department, also re-evaluated alternative methods of heating classrooms, to ensure a safe and healthy environment for students. It was in this context, that John Joyce's company [[Bowin Technology]] embarked on a major research & development program aimed at minimising nitrogen dioxide [[emissions]] from unflued gas heaters. Bowin Technology set itself the task of solving the emission problem at its source: the [[bunsen burner|gas burner]]. This was despite a generally long held belief by gas experts, that commercially warranted gas burner improvements could not deliver drastic nitrogen oxides (NO<sub>x</sub>) reductions. In 1989, an immediate call to reduce the indoor nitrogen dioxide (NO<sub>2</sub>) level, was triggered by widely publicised articles and media coverage in New South Wales, highlighting the effect this chemical has on [[respiratory]] sensitive people, such as [[asthma]]tics and those with [[bronchial]] problems. In the heat of the indoor air quality debate various State institutions in Australia were advised to switch to flued gas heaters and [[electric heating]]. New South Wales in contrast, through combined action by [[Australian Gas Light Company]], Health Authorities and the New South Wales Public Works Department, formulated initial indoor air quality guidelines. These guidelines formed the basis for Australian Gas Appliance Code restrictions for nitrogen dioxide NO<sub>2</sub>emissions from unflued heaters, now adopted Australia wide<ref>AS 4553-2000 (AG 103-2000) Gas space heating appliances</ref>. . John Joyce became aware that no other overseas regulatory body made a distinction between NO and NO<sub>2</sub> in their environmental guidelines or codes. Furthermore it appeared that total nitrogen oxides level requirements were in place irrespective of whether emissions were flued or not. Consequently John Joyce learned that a 'harmless' part of NO<sub>x</sub> emissions [[nitric oxide]] (NO), in the presence of [[hydrocarbon]]s (such as household [[aerosol spray|aerosol propellants]], possible gas leaks and ingress of vehicle exhaust fume), converts to NO<sub>2</sub>. This was found to be the case in the New South Wales school investigation.<ref>S McPhail and A Betts; ''Flueless gas heaters in NSW Government Schools'' Proc 11th Clean Air Conf, Clean Air Soc Aust and New Zealand,5-10 July 1992,Brisbane</ref> In a scientific sense it had become practice to calculate both NO + NO<sub>2</sub>, when measuring oxides of nitrogen levels in emissions. Hence the now commonly used reference to "total NO<sub>x</sub>". ===Greenhouse gas and photochemical smog=== [[Natural gas]] by composition has a distinct advantage over other [[fossil fuel]]s in terms of [[carbon dioxide]], [[particulate]] and [[sulfur dioxide]]s produced when converting to useful [[energy]]. In the early 1990s numerous countries were in the process of substituting oil and coal with natural gas for their energy and [[electric power]] needs. To maintain this advantage as an "environmentally friendly" fuel, Australian gas utilities are effectively reducing gas losses (methane emissions) in their deliveries, and impose strict codes on appliance manufacturers and installers against [[gas leak]]age. Nevertheless environmental experts see the production of oxides of nitrogen as a major menace in the formation of [[greenhouse gas|greenhouse gases]] and [[photochemical smog]]. The interaction of [[NOx]] with hydrocarbons from vehicle [[exhaust]]s and sunlight, can also form low level [[ozone]]. In the [[stratosphere]] (some 25 km up). Ozone is helpful by absorbing the fiercer part of the [[ultraviolet radiation]] of the sun, but at ground level it damages materials and vegetation. It irritates throat, lungs and eyes, and strenuous exercise or work can become painful. Furthermore, the effectiveness of [[nitrous oxide]] as a greenhouse gas is magnified by its longer life than [[carbon dioxide]], [[methane]] and CFC's. In essence the rate at which low level ozone is formed is determined by hydrocarbons, whilst the availability of oxides of nitrogen influences the amount it produces. At this point the environmental debate takes a surprising turn as individual industries tend to blame each other's emission as a probable cause. ===Best Available Control Technology (BACT)=== It is well established that conventional "[[bunsen burner|blue flame]]" or bunsen gas burners produce oxides of nitrogen at levels of 30-50 nanograms per joule<ref>''Ultra-Low NO<sub>2</sub> Unflued Gas Heater Study'', Dr Ibrahim Tas, 2004 </ref><ref>J Bromly and Dong-ke Zhang,''Comment on Published Paper Dealing with Unflued Gas Space Heaters in Schools by Louis S Pilotto and Co-authors'' Centre for Fuels and Energy, [[Curtin University of Technology]], Perth, WA, 2004</ref>and are as such not considered to have potential for NOx reduction. [[Surface combustion]] burners or radiant tile burners in comparison produce nitrogen oxides' levels 60-70% less<ref>J Bromly and Dong-ke Zhang,''Comment on Published Paper Dealing with Unflued Gas Space Heaters in Schools by Louis S Pilotto and Co-authors'' centre For Fuels and Energy Curtin University of Technology, Perth, WA,2004</ref>. Therefore John Joyce's research into low NO<sub>x</sub> burners revolved primarily around surface combustion techniques. Another issue was the effect combustion temperatures have on the formation of NO<sub>x</sub>. John Joyce's task became even more challenging when he decided not to direct his development towards radiant type surface combustion tiles. The use of radiant heating for most institutional purposes (other than spot heating) is considered impractical as is too hot close to the heater, while the loss of [[radiant heat]] over a distance to be reached is quite dramatic. Investigations into numerous developments of other types of "low NOx" burners showed that so far such burners were either too complex in design or operation, too expensive or unsuitable. John Joyce's plan was to use high temperature steel mesh, and went on to produce scores of [[prototype]] burners until one showed "potential". The scientific innovative nature of John Joyce's LO-NO<sub>x</sub> technologies are confirmed by full [[patent]] protection in [[Australia]], [[United States]], [[United Kingdom]], [[Japan]], [[Italy]] and [[France]]. In 1993 John Joyce received an Australian Design Award and Powerhouse Museum Selection status for his "SLE" heater range, which incorporate LO-NO<sub>x</sub> burners. The Australian Academy of Design selected the SLE [[unflued gas heater]] range to be featured in the Design Showcase during the "Innovation by Design" National Conference in October 1994 In the United States, John Joyce's LO-NO <sub>x</sub>[[water heater]] burners have successfully undergone a series of exhaustive tests to prove that these particular burners do not act as an ignition source in the presence of flammable vapours, resulting from accidental fuel spillage. They have also been extensive tests carried out to verify its reduction of NO<sub>2</sub>. ===Energy efficiencies=== More tangible cost savings are defined when comparing the energy efficiencies of gas heaters with low NO<sub>x</sub> emissions with conventional flued types. Gas heaters with emission problems are flued and inherently lose substantial energies in the form of hot flue gases to the atmosphere. In addition, the choice of placement of flued heaters is greatly impaired due to flue installation restrictions. In contrast, dedicated low emission gas heaters do not require a flue system. Furthermore, with the introduction of [[oxygen depletion pilot|oxygen depletion sensors]] and thermostatic controls, they do not place critical reliance on ventilation as previously was the case. These heaters can be positioned more conveniently and centralised to affect optimum warm air distribution. By definition unflued low NO<sub>x</sub> gas heaters are 100% efficient as all heat energy released from the flame is converted to useful heat. ==Applications of technology== * Gas-fired unflued gas heaters * Gas-fired flued gas heaters * Gas-fired storage water heaters <!-- Deleted image removed: [[Image:sle pic.gif|thumb|left|Bowin Low NOx unflued convection gas appliance]] --> <!-- Deleted image removed: [[Image:Lb90 pic.gif|thumb|left|Bowin Low NOx commercial unflued convection gas appliance]] --> [[Image:Pic pf.gif|thumb|left|Bowin PF25/35 Low NOx Power Commercial Flued gas appliance]] <!-- Unsourced image removed: [[Image:xle_pic.gif|thumb|left|Bowin XLE25/35 Low NOx Power Flued gas appliance]] --> <br clear=all> ==References== <references/> ==External links== * [http://www.deh.gov.au/atmosphere/airquality/publications/residential/index.html Nitrogen oxides emissions standards for domestic gas appliances a background study - Features Bowin LOx NOx Burner] * [http://www.gamaa.asn.au/fieldstudy.htm Ultra-Low NO2 Unflued Gas Heater Study] * [http://www.ixc.com.au/resource/detail.html?returnuri=%2Fcontent.php%2F12.html%3Fform_page%3D7&form_resourceid=5698 Australian Technology Showcase - Bowin Ultra Low Nox Gas Burner System] * [http://www.designawards.com.au/ADA/INFO/DIRECTORY/DIRECTORY.HTM Australian Design Award Winner Ranking (Bowin Listed)] * [http://www.designawards.com.au/ADA/99-00/INDUSTRIAL%20DESIGN/032/032.HTM Bowin Power Flue Gas Heater Awarded Australian Design Award] * [http://www.ausindustry.gov.au/content/content.cfm?ObjectID=F35FB7A0-5B22-4524-B7BE81D7FA532484&L3Keyword=spatial Australia’s Best Technology on Display (Bowin Technology listed) - AusIndustry] * [http://www.consensus.com.au/ManufacturingAwards/CMAarchive/CMA2002/insidemanufacturing2002.htm Design and manufacturing article featuring Bowin products] * [http://www.jidpo.or.jp/worlddesign/backnumber/australia/consumer/products03-e.html Japanese Industrial Design Promotional Organisation Featuring Bowin Products] * [http://www.bowin.com.au Bowin Company website] * [http://www.pcc-sterling.com. Process Combustion Low NOx Burners] * [http://www.burnercombustion.com/miura_emissions.htm Low NOx burners using quenched flames] * [http://www.bloomeng.com. Bloom Engineering Low NOx Burners & Baffle Burners] [[Category:Pollution control technologies]] [[Category:Air pollution control systems]] [[Category:NOx control]]