[{"data":1,"prerenderedAt":768},["ShallowReactive",2],{"site-footer-common":3,"glossary:nox-sox-co":45,"glossary-related:nox-sox-co":266},{"id":4,"extension":5,"footer":6,"meta":40,"navbar":41,"stem":43,"__hash__":44},"common\u002Fcommon.yml","yml",{"tagline":7,"links":8,"sections":9},"Acoustic cleaning intelligence for industrial fouling, soot, ash, dust and build-up.",[],[10,19,31],{"title":11,"links":12},"Product",[13,16],{"label":14,"to":15},"How it works","\u002F#product",{"label":17,"to":18},"Cost assessment","\u002F#hero",{"title":20,"links":21},"Company",[22,25,28],{"label":23,"to":24},"What we build","\u002F#about",{"label":26,"to":27},"Careers","\u002F#careers",{"label":29,"to":30},"Contact","\u002F#contact",{"title":32,"links":33},"Resources",[34,37],{"label":35,"to":36},"Blog","\u002Fresources\u002Fblog",{"label":38,"to":39},"Glossary","\u002Fglossary",{},{"links":42},[],"common","YocmZRy1AYfBbpgGVms-zhdiABlF8VTxHx6h4rDmZBA",{"id":46,"title":47,"aliases":48,"body":56,"category":245,"description":246,"extension":247,"meta":248,"navigation":249,"path":250,"relatedTerms":251,"seo":256,"sources":259,"stem":263,"term":264,"__hash__":265},"glossary\u002Fglossary\u002Fnox-sox-co.md","NOx \u002F SOx \u002F CO",[49,50,51,52,53,54,55],"NOx","SOx","SO2","CO emissions","nitrogen oxides","sulphur oxides","carbon monoxide",{"type":57,"value":58,"toc":238},"minimark",[59,84,89,171,175,182,211,215],[60,61,62,65,66,68,69,72,73,78,79,83],"p",{},[63,64,49],"strong",{}," (nitrogen oxides — NO and NO₂), ",[63,67,50],{}," (sulphur oxides — primarily SO₂ with smaller SO₃), and ",[63,70,71],{},"CO"," (carbon monoxide) are the principal regulated gaseous emissions from combustion plants, alongside ",[74,75,77],"a",{"href":76},"\u002Fglossary\u002Fparticulate-matter","particulate matter",". All three are measured continuously by ",[74,80,82],{"href":81},"\u002Fglossary\u002Fcems","CEMS"," and permit-limited under most jurisdictions' emission codes.",[85,86,88],"h2",{"id":87},"sources-and-controls","Sources and controls",[90,91,92,108],"table",{},[93,94,95],"thead",{},[96,97,98,102,105],"tr",{},[99,100,101],"th",{},"Pollutant",[99,103,104],{},"Formation",[99,106,107],{},"Control",[109,110,111,133,146,159],"tbody",{},[96,112,113,118,121],{},[114,115,116],"td",{},[63,117,49],{},[114,119,120],{},"Thermal NOx (high flame temperature) + fuel NOx",[114,122,123,124,128,129],{},"Combustion control + ",[74,125,127],{"href":126},"\u002Fglossary\u002Fselective-catalytic-reduction","SCR"," \u002F ",[74,130,132],{"href":131},"\u002Fglossary\u002Fselective-non-catalytic-reduction","SNCR",[96,134,135,140,143],{},[114,136,137],{},[63,138,139],{},"SO₂",[114,141,142],{},"Fuel sulphur oxidation",[114,144,145],{},"Fuel selection + FGD (wet scrubber, dry sorbent injection)",[96,147,148,153,156],{},[114,149,150],{},[63,151,152],{},"SO₃",[114,154,155],{},"Catalytic oxidation of SO₂ over V₂O₅ in SCR",[114,157,158],{},"Catalyst formulation + temperature control",[96,160,161,165,168],{},[114,162,163],{},[63,164,71],{},[114,166,167],{},"Incomplete combustion",[114,169,170],{},"Combustion control (excess air, residence time, temperature)",[85,172,174],{"id":173},"how-cleaning-affects-gaseous-emissions","How cleaning affects gaseous emissions",[60,176,177,181],{},[74,178,180],{"href":179},"\u002Fglossary\u002Fsonic-horn","Sonic horns"," do not directly capture gaseous pollutants but support gaseous-emission control indirectly:",[183,184,185,195,206],"ul",{},[186,187,188,190,191,194],"li",{},[63,189,49],{}," — clean ",[74,192,193],{"href":126},"SCR catalysts"," achieve their rated NOx reduction; fouled catalysts under-perform",[186,196,197,200,201,205],{},[63,198,199],{},"SO₃ and downstream ABS"," — keeping the cold end clean reduces ",[74,202,204],{"href":203},"\u002Fglossary\u002Fammonium-bisulphate","ammonium-bisulphate"," accumulation",[186,207,208,210],{},[63,209,71],{}," — preserved boiler performance maintains stable combustion",[85,212,214],{"id":213},"related-terms","Related terms",[183,216,217,222,226,232],{},[186,218,219],{},[74,220,221],{"href":126},"Selective Catalytic Reduction (SCR)",[186,223,224],{},[74,225,82],{"href":81},[186,227,228],{},[74,229,231],{"href":230},"\u002Fglossary\u002Fopacity","Opacity",[186,233,234],{},[74,235,237],{"href":236},"\u002Fglossary\u002Findustrial-emissions-directive","Industrial Emissions Directive (IED)",{"title":239,"searchDepth":240,"depth":240,"links":241},"",2,[242,243,244],{"id":87,"depth":240,"text":88},{"id":173,"depth":240,"text":174},{"id":213,"depth":240,"text":214},"kpis-measurements","NOx (nitrogen oxides — NO and NO₂), SOx (sulphur oxides — primarily SO₂ with smaller SO₃), and CO (carbon monoxide) are the principal regulated gaseous emissions from combustion plants, alongside particulate matter. All three are measured continuously by CEMS and permit-limited under most jurisdictions' emission codes.","md",{},true,"\u002Fglossary\u002Fnox-sox-co",[252,253,254,255],"selective-catalytic-reduction","cems","opacity","industrial-emissions-directive",{"title":257,"description":258},"NOx, SOx and CO — the principal regulated gaseous combustion emissions","NOx (nitrogen oxides), SOx (sulphur oxides) and CO (carbon monoxide) are the principal regulated gaseous emissions from combustion plants. Continuously measured by CEMS.",[260],{"title":261,"url":262},"Wikipedia — NOx","https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FNOx","glossary\u002Fnox-sox-co","NOx, SOx and CO emissions","9pJ6fb01njwEN5SRakWsRmyc0WBaWxUnIeQ3cnLm7Xc",[267,436,552,657],{"id":268,"title":221,"aliases":269,"body":272,"category":411,"description":412,"extension":247,"meta":413,"navigation":249,"path":126,"relatedTerms":414,"seo":423,"sources":426,"stem":433,"term":434,"__hash__":435},"glossary\u002Fglossary\u002Fselective-catalytic-reduction.md",[127,270,271],"SCR system","SCR reactor",{"type":57,"value":273,"toc":406},[274,293,297,313,317,320,349,366,368],[60,275,276,278,279,283,284,288,289,292],{},[63,277,221],{}," is the dominant flue-gas NOx-control technology on coal-fired and gas-fired utility boilers, ",[74,280,282],{"href":281},"\u002Fglossary\u002Fheat-recovery-steam-generator","HRSGs"," in combined-cycle plants, ",[74,285,287],{"href":286},"\u002Fglossary\u002Fwaste-to-energy","waste-to-energy"," and ",[74,290,291],{"href":286},"biomass"," boilers, cement plants and major refining furnaces. Ammonia or aqueous urea is injected upstream of a catalyst bed; the catalyst lowers the activation energy for the reaction NOx + NH₃ → N₂ + H₂O, achieving 80–95% NOx reduction across the reactor.",[85,294,296],{"id":295},"reactor-layout","Reactor layout",[60,298,299,300,304,305,308,309,312],{},"A typical SCR reactor is a vertical or horizontal duct containing 2–4 layers of catalyst modules. Upstream of the catalyst sits the ",[74,301,303],{"href":302},"\u002Fglossary\u002Fammonia-injection-grid","ammonia injection grid (AIG)"," that distributes the ammonia evenly into the flue gas. Most installations operate in the ",[63,306,307],{},"high-dust"," position (between economiser and air heater) where catalyst temperature is around 300–400 °C; ",[63,310,311],{},"tail-end"," SCRs sit downstream of particulate control at lower temperatures, with the trade-off of needing flue-gas reheating.",[85,314,316],{"id":315},"fouling-and-cleaning","Fouling and cleaning",[60,318,319],{},"SCR catalysts foul in two ways:",[183,321,322,340],{},[186,323,324,330,331,288,335,339],{},[63,325,326],{},[74,327,329],{"href":328},"\u002Fglossary\u002Fcatalyst-pluggage","Pluggage"," — fly ash, ",[74,332,334],{"href":333},"\u002Fglossary\u002Fpopcorn-ash","popcorn ash",[74,336,338],{"href":337},"\u002Fglossary\u002Flarge-particle-ash","large-particle ash"," wedge into the catalyst cells, blocking the gas path",[186,341,342,348],{},[63,343,344],{},[74,345,347],{"href":346},"\u002Fglossary\u002Fcatalyst-masking","Masking"," — a thin layer of deposit covers the active sites; gas flow continues but catalytic activity falls",[60,350,351,352,356,357,361,362,365],{},"Both reduce NOx-reduction efficiency, raise ",[74,353,355],{"href":354},"\u002Fglossary\u002Fammonia-slip","ammonia slip",", and shorten catalyst life. Cleaning options include steam ",[74,358,360],{"href":359},"\u002Fglossary\u002Fsteam-sootblower","sootblowers",", ",[74,363,364],{"href":179},"sonic horns"," and offline campaigns (vacuum \u002F water wash \u002F regeneration). Sonic horns are increasingly favoured because they continuously dislodge ash before it cements onto the catalyst face, without the steam erosion of mechanical sootblowing.",[85,367,214],{"id":213},[183,369,370,375,380,385,390,395,401],{},[186,371,372],{},[74,373,374],{"href":131},"Selective Non-Catalytic Reduction (SNCR)",[186,376,377],{},[74,378,379],{"href":302},"Ammonia injection grid",[186,381,382],{},[74,383,384],{"href":354},"Ammonia slip",[186,386,387],{},[74,388,389],{"href":346},"Catalyst masking",[186,391,392],{},[74,393,394],{"href":328},"Catalyst pluggage",[186,396,397],{},[74,398,400],{"href":399},"\u002Fglossary\u002Fhoneycomb-catalyst","Honeycomb catalyst",[186,402,403],{},[74,404,405],{"href":179},"Sonic horn",{"title":239,"searchDepth":240,"depth":240,"links":407},[408,409,410],{"id":295,"depth":240,"text":296},{"id":315,"depth":240,"text":316},{"id":213,"depth":240,"text":214},"scr-sncr","Selective Catalytic Reduction (SCR) is the dominant flue-gas NOx-control technology on coal-fired and gas-fired utility boilers, HRSGs in combined-cycle plants, waste-to-energy and biomass boilers, cement plants and major refining furnaces. Ammonia or aqueous urea is injected upstream of a catalyst bed; the catalyst lowers the activation energy for the reaction NOx + NH₃ → N₂ + H₂O, achieving 80–95% NOx reduction across the reactor.",{},[415,416,417,418,419,420,421,422],"selective-non-catalytic-reduction","denox","ammonia-injection-grid","ammonia-slip","catalyst-masking","catalyst-pluggage","honeycomb-catalyst","sonic-horn",{"title":424,"description":425},"Selective Catalytic Reduction (SCR) — how the dominant NOx-control technology works","SCR is the dominant NOx-control technology on industrial combustion plant. Ammonia is injected upstream of a catalyst that converts NOx to nitrogen and water.",[427,430],{"title":428,"url":429},"Wikipedia — Selective catalytic reduction","https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FSelective_catalytic_reduction",{"title":431,"url":432},"Power Engineering — SCR Catalyst Cleaning: Sootblowers vs. Acoustic Horns","https:\u002F\u002Fwww.power-eng.com\u002Foperations-maintenance\u002Fscr-catalyst-cleaningsootblowers-vs-acoustic-horns\u002F","glossary\u002Fselective-catalytic-reduction","Selective Catalytic Reduction","fmMCMd4NY3eZdSk_UYlbZ9ryi-9CR2Os6DivQjXEPCU",{"id":437,"title":438,"aliases":439,"body":441,"category":245,"description":536,"extension":247,"meta":537,"navigation":249,"path":81,"relatedTerms":538,"seo":542,"sources":545,"stem":549,"term":550,"__hash__":551},"glossary\u002Fglossary\u002Fcems.md","Continuous Emissions Monitoring System (CEMS)",[82,440],"continuous emissions monitor",{"type":57,"value":442,"toc":531},[443,457,461,464,489,493,509,511],[60,444,445,446,448,449,361,451,361,453,456],{},"A ",[63,447,438],{}," is the suite of instruments that measures stack emissions in real time. A typical industrial CEMS measures ",[74,450,254],{"href":230},[74,452,77],{"href":76},[74,454,455],{"href":250},"NOx, SOx, CO",", O₂, moisture and gas flow. CEMS data is the primary basis for environmental-compliance reporting under most jurisdictions' emission permits.",[85,458,460],{"id":459},"cems-quality-assurance","CEMS quality assurance",[60,462,463],{},"CEMS instruments are governed by quality-assurance frameworks:",[183,465,466,477,483],{},[186,467,468,471,472,476],{},[63,469,470],{},"EU"," — ",[74,473,475],{"href":474},"\u002Fglossary\u002Fen-14181-en-13284","EN 14181"," (QAL1, QAL2, QAL3 and AST)",[186,478,479,482],{},[63,480,481],{},"US"," — EPA Reference Method 6, 7, 19 etc. plus Part 75 CEMS requirements",[186,484,485,488],{},[63,486,487],{},"National regulators"," — various local specifics",[85,490,492],{"id":491},"how-cleaning-intersects-with-cems-data","How cleaning intersects with CEMS data",[60,494,495,496,500,501,505,506,508],{},"Operators see fouling-driven degradation of ",[74,497,499],{"href":498},"\u002Fglossary\u002Felectrostatic-precipitator","ESP"," or ",[74,502,504],{"href":503},"\u002Fglossary\u002Fbaghouse","baghouse"," performance in near-real-time on the CEMS trace. A rising opacity baseline, more frequent excursions, or trended particulate increase all indicate worsening collection. Active ",[74,507,422],{"href":179}," cleaning that defends collection efficiency shows up on CEMS as flatter, lower, more predictable traces.",[85,510,214],{"id":213},[183,512,513,517,522,526],{},[186,514,515],{},[74,516,231],{"href":230},[186,518,519],{},[74,520,521],{"href":76},"Particulate matter",[186,523,524],{},[74,525,47],{"href":250},[186,527,528],{},[74,529,530],{"href":474},"EN 14181 \u002F EN 13284",{"title":239,"searchDepth":240,"depth":240,"links":532},[533,534,535],{"id":459,"depth":240,"text":460},{"id":491,"depth":240,"text":492},{"id":213,"depth":240,"text":214},"A Continuous Emissions Monitoring System (CEMS) is the suite of instruments that measures stack emissions in real time. A typical industrial CEMS measures opacity, particulate matter, NOx, SOx, CO, O₂, moisture and gas flow. CEMS data is the primary basis for environmental-compliance reporting under most jurisdictions' emission permits.",{},[254,539,540,541],"particulate-matter","nox-sox-co","en-14181-en-13284",{"title":543,"description":544},"Continuous Emissions Monitoring System (CEMS) — real-time stack emissions measurement","CEMS instruments measure stack emissions in real time — opacity, PM, NOx, SOx, CO, O2, moisture — providing the data on which environmental compliance is judged.",[546],{"title":547,"url":548},"Wikipedia — Continuous emissions monitoring system","https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FContinuous_emissions_monitoring_system","glossary\u002Fcems","Continuous Emissions Monitoring System","d4nlsLBIEd3NGEvGY4Qyqp_PhX2UOjgAnwxx__vQ_V4",{"id":553,"title":231,"aliases":554,"body":557,"category":245,"description":643,"extension":247,"meta":644,"navigation":249,"path":230,"relatedTerms":645,"seo":647,"sources":650,"stem":654,"term":655,"__hash__":656},"glossary\u002Fglossary\u002Fopacity.md",[555,556],"stack opacity","opacity excursion",{"type":57,"value":558,"toc":638},[559,567,571,574,607,611,616,618],[60,560,561,563,564,566],{},[63,562,231],{}," is the percentage of light obscured by particulate matter in stack flue gas, measured continuously by a transmissometer (opacity monitor) installed in the stack. Opacity is the headline visual KPI for ",[74,565,499],{"href":498}," performance and is permit-limited in most jurisdictions — typically 20–40% on a 6-minute rolling average, with absolute peaks limited to 60% for shorter periods.",[85,568,570],{"id":569},"opacity-excursions","Opacity excursions",[60,572,573],{},"Opacity excursions are typically driven by:",[183,575,576,588,594,601,604],{},[186,577,578,582,583,587],{},[74,579,581],{"href":580},"\u002Fglossary\u002Fesp-rapper","ESP rapping"," ",[74,584,586],{"href":585},"\u002Fglossary\u002Fre-entrainment","re-entrainment"," puffs",[186,589,590,593],{},[74,591,592],{"href":503},"Baghouse"," bag failure (sudden particulate breakthrough)",[186,595,596,600],{},[74,597,599],{"href":598},"\u002Fglossary\u002Fback-corona","ESP back-corona"," collapse",[186,602,603],{},"Combustion upsets producing unusually high inlet particulate",[186,605,606],{},"Soot-blower-triggered re-entrainment",[85,608,610],{"id":609},"how-sonic-horns-reduce-opacity","How sonic horns reduce opacity",[60,612,613,615],{},[74,614,180],{"href":179}," deliver continuous gentle dust release rather than periodic aggressive rapping puffs. Plants retrofitting horns on opacity-limited ESPs commonly see 20–40% opacity-peak reduction without other changes — the headline business case for many sonic-horn ESP installations.",[85,617,214],{"id":213},[183,619,620,624,629,634],{},[186,621,622],{},[74,623,82],{"href":81},[186,625,626],{},[74,627,628],{"href":498},"Electrostatic precipitator",[186,630,631],{},[74,632,633],{"href":585},"Re-entrainment",[186,635,636],{},[74,637,405],{"href":179},{"title":239,"searchDepth":240,"depth":240,"links":639},[640,641,642],{"id":569,"depth":240,"text":570},{"id":609,"depth":240,"text":610},{"id":213,"depth":240,"text":214},"Opacity is the percentage of light obscured by particulate matter in stack flue gas, measured continuously by a transmissometer (opacity monitor) installed in the stack. Opacity is the headline visual KPI for ESP performance and is permit-limited in most jurisdictions — typically 20–40% on a 6-minute rolling average, with absolute peaks limited to 60% for shorter periods.",{},[253,646,586,422],"electrostatic-precipitator",{"title":648,"description":649},"Opacity — visual stack-emission KPI measured by continuous monitor","Opacity is the percentage of light obscured by particulate in stack flue gas. The headline visual KPI for ESP performance; continuously monitored and permit-limited.",[651],{"title":652,"url":653},"Wikipedia — Opacity","https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FOpacity_(optics)","glossary\u002Fopacity","Opacity (stack)","-4RIuJbd3zg7kip6GHWTZ5efGSK8D9bOiK_nb9oMGWo",{"id":658,"title":237,"aliases":659,"body":662,"category":750,"description":751,"extension":247,"meta":752,"navigation":249,"path":236,"relatedTerms":753,"seo":758,"sources":761,"stem":765,"term":766,"__hash__":767},"glossary\u002Fglossary\u002Findustrial-emissions-directive.md",[660,661],"IED","2010\u002F75\u002FEU",{"type":57,"value":663,"toc":745},[664,675,679,703,707,720,722],[60,665,666,667,670,671,674],{},"The ",[63,668,669],{},"Industrial Emissions Directive (IED, 2010\u002F75\u002FEU)"," is the umbrella EU directive on industrial pollution control. It establishes Best Available Techniques (BAT) as the basis for emission-limit-value setting across major industrial sectors — large combustion plants, ",[74,672,673],{"href":286},"WtE",", cement and lime, glass, iron and steel, refining, chemicals, food processing, and many others.",[85,676,678],{"id":677},"how-ied-works-in-practice","How IED works in practice",[183,680,681,684,692,695],{},[186,682,683],{},"IED requires Member States to issue integrated environmental permits to covered installations",[186,685,686,687,691],{},"Each sector has its own ",[74,688,690],{"href":689},"\u002Fglossary\u002Fbat-ael-bref","BREF"," document defining BAT",[186,693,694],{},"Permits must set emission limits within the BAT-AEL ranges",[186,696,697,698,702],{},"Compliance is enforced by Member State authorities (e.g. ",[74,699,701],{"href":700},"\u002Fglossary\u002Fbimschv","BImSchV"," in Germany, the Environment Agency in England)",[85,704,706],{"id":705},"implications-for-sonic-horn-business","Implications for sonic-horn business",[60,708,709,710,361,712,288,714,716,717,719],{},"IED's BAT framework increasingly recognises continuous performance preservation of pollution-control equipment as part of best practice. Active cleaning that prevents ",[74,711,499],{"href":498},[74,713,504],{"href":503},[74,715,127],{"href":126}," performance from drifting over the operating cycle has implicit regulatory support — though no BREF mandates ",[74,718,364],{"href":179}," by name.",[85,721,214],{"id":213},[183,723,724,729,733,739],{},[186,725,726],{},[74,727,728],{"href":689},"BAT-AEL \u002F BREF",[186,730,731],{},[74,732,701],{"href":700},[186,734,735],{},[74,736,738],{"href":737},"\u002Fglossary\u002Fta-luft-2021","TA Luft 2021",[186,740,741],{},[74,742,744],{"href":743},"\u002Fglossary\u002Feu-ets","EU ETS",{"title":239,"searchDepth":240,"depth":240,"links":746},[747,748,749],{"id":677,"depth":240,"text":678},{"id":705,"depth":240,"text":706},{"id":213,"depth":240,"text":214},"standards-regulations","The Industrial Emissions Directive (IED, 2010\u002F75\u002FEU) is the umbrella EU directive on industrial pollution control. It establishes Best Available Techniques (BAT) as the basis for emission-limit-value setting across major industrial sectors — large combustion plants, WtE, cement and lime, glass, iron and steel, refining, chemicals, food processing, and many others.",{},[754,755,756,757],"bat-ael-bref","bimschv","ta-luft-2021","eu-ets",{"title":759,"description":760},"Industrial Emissions Directive (IED) — EU framework for industrial pollution control","The IED (2010\u002F75\u002FEU) is the umbrella EU directive on industrial pollution control. Sets BAT (Best Available Techniques) as the basis for emission limits across major industrial sectors.",[762],{"title":763,"url":764},"Wikipedia — Industrial Emissions Directive","https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FIndustrial_Emissions_Directive","glossary\u002Findustrial-emissions-directive","Industrial Emissions Directive","MNARNMHkPCkJoQ6cvwepPa9PKodFxAzHonMaCpka1_c",1782613746078]