[{"data":1,"prerenderedAt":1123},["ShallowReactive",2],{"site-footer-common":3,"glossary:catalyst-pluggage":45,"glossary-related:catalyst-pluggage":226},{"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":52,"category":205,"description":206,"extension":207,"meta":208,"navigation":209,"path":210,"relatedTerms":211,"seo":217,"sources":220,"stem":224,"term":47,"__hash__":225},"glossary\u002Fglossary\u002Fcatalyst-pluggage.md","Catalyst pluggage",[49,50,51],"catalyst plugging","catalyst channelling","SCR catalyst pluggage",{"type":53,"value":54,"toc":198},"minimark",[55,73,78,117,121,162,166],[56,57,58,61,62,67,68,72],"p",{},[59,60,47],"strong",{}," is the physical blockage of ",[63,64,66],"a",{"href":65},"\u002Fglossary\u002Fselective-catalytic-reduction","SCR catalyst"," channels by particulate material. Unlike ",[63,69,71],{"href":70},"\u002Fglossary\u002Fcatalyst-masking","catalyst masking"," (a thin surface blanket), pluggage fills the catalyst channels themselves, stopping gas flow through affected cells. The result is ΔP rise across the SCR, gas-flow maldistribution into the remaining open cells, and channelling effects that reduce overall NOx reduction.",[74,75,77],"h2",{"id":76},"sources-of-pluggage-material","Sources of pluggage material",[79,80,81,91,100,111],"ul",{},[82,83,84,90],"li",{},[59,85,86],{},[63,87,89],{"href":88},"\u002Fglossary\u002Flarge-particle-ash","Large-particle ash (LPA)"," — slag fragments and agglomerated ash carried over from the boiler",[82,92,93,99],{},[59,94,95],{},[63,96,98],{"href":97},"\u002Fglossary\u002Fpopcorn-ash","Popcorn ash"," — porous low-density ash particles that wedge into honeycomb cells",[82,101,102,105,106,110],{},[59,103,104],{},"Ammonium-salt deposits"," — ",[63,107,109],{"href":108},"\u002Fglossary\u002Fammonium-bisulphate","ammonium bisulphate"," on tail-end SCRs at lower temperatures",[82,112,113,116],{},[59,114,115],{},"Refractory debris"," — fragments from upstream furnace or duct repairs",[74,118,120],{"id":119},"prevention","Prevention",[79,122,123,129,135,141,152],{},[82,124,125,128],{},[59,126,127],{},"LPA screens"," — coarse mesh screens upstream of the catalyst trap large particles",[82,130,131,134],{},[59,132,133],{},"Guard layers"," — sacrificial top catalyst layer with larger pitch absorbs the initial particulate",[82,136,137,140],{},[59,138,139],{},"Larger pitch on the top layer"," — wider cell openings on the first catalyst layer pass LPA through to a removable screen below",[82,142,143,151],{},[59,144,145,146,150],{},"Periodic ",[63,147,149],{"href":148},"\u002Fglossary\u002Fsonic-horn","sonic-horn"," cleaning"," — dislodges accumulating ash before it cements",[82,153,154,161],{},[59,155,156,157],{},"Steam ",[63,158,160],{"href":159},"\u002Fglossary\u002Fsonic-sootblower","sootblowing"," — for harder deposits",[74,163,165],{"id":164},"related-terms","Related terms",[79,167,168,173,178,182,187,193],{},[82,169,170],{},[63,171,172],{"href":65},"Selective Catalytic Reduction (SCR)",[82,174,175],{},[63,176,177],{"href":88},"Large-particle ash",[82,179,180],{},[63,181,98],{"href":97},[82,183,184],{},[63,185,186],{"href":70},"Catalyst masking",[82,188,189],{},[63,190,192],{"href":191},"\u002Fglossary\u002Fhoneycomb-catalyst","Honeycomb catalyst",[82,194,195],{},[63,196,197],{"href":148},"Sonic horn",{"title":199,"searchDepth":200,"depth":200,"links":201},"",2,[202,203,204],{"id":76,"depth":200,"text":77},{"id":119,"depth":200,"text":120},{"id":164,"depth":200,"text":165},"scr-sncr","Catalyst pluggage is the physical blockage of SCR catalyst channels by particulate material. Unlike catalyst masking (a thin surface blanket), pluggage fills the catalyst channels themselves, stopping gas flow through affected cells. The result is ΔP rise across the SCR, gas-flow maldistribution into the remaining open cells, and channelling effects that reduce overall NOx reduction.","md",{},true,"\u002Fglossary\u002Fcatalyst-pluggage",[212,213,214,215,216,149],"selective-catalytic-reduction","large-particle-ash","popcorn-ash","catalyst-masking","honeycomb-catalyst",{"title":218,"description":219},"Catalyst pluggage — channel blockage that reduces SCR gas flow","Catalyst pluggage is the physical blockage of SCR catalyst channels by large-particle ash, popcorn ash or ammonium-salt deposits. It causes ΔP rise and gas-flow maldistribution.",[221],{"title":222,"url":223},"Airflow Sciences — SCR Catalyst Pluggage Reduction at Roxboro Unit 3","https:\u002F\u002Fwww.airflowsciences.com\u002Fsites\u002Fdefault\u002Ffiles\u002Fdocs\u002F2010_MEGA_Symposium_Roxboro_U3.pdf","glossary\u002Fcatalyst-pluggage","m2viiLe19KKcTBiDWhyUc38xPIzoOiMpL15r0i_ayHg",[227,385,490,580,739,894],{"id":228,"title":172,"aliases":229,"body":233,"category":205,"description":364,"extension":207,"meta":365,"navigation":209,"path":65,"relatedTerms":366,"seo":372,"sources":375,"stem":382,"term":383,"__hash__":384},"glossary\u002Fglossary\u002Fselective-catalytic-reduction.md",[230,231,232],"SCR","SCR system","SCR reactor",{"type":53,"value":234,"toc":359},[235,254,258,274,278,281,306,323,325],[56,236,237,239,240,244,245,249,250,253],{},[59,238,172],{}," is the dominant flue-gas NOx-control technology on coal-fired and gas-fired utility boilers, ",[63,241,243],{"href":242},"\u002Fglossary\u002Fheat-recovery-steam-generator","HRSGs"," in combined-cycle plants, ",[63,246,248],{"href":247},"\u002Fglossary\u002Fwaste-to-energy","waste-to-energy"," and ",[63,251,252],{"href":247},"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.",[74,255,257],{"id":256},"reactor-layout","Reactor layout",[56,259,260,261,265,266,269,270,273],{},"A typical SCR reactor is a vertical or horizontal duct containing 2–4 layers of catalyst modules. Upstream of the catalyst sits the ",[63,262,264],{"href":263},"\u002Fglossary\u002Fammonia-injection-grid","ammonia injection grid (AIG)"," that distributes the ammonia evenly into the flue gas. Most installations operate in the ",[59,267,268],{},"high-dust"," position (between economiser and air heater) where catalyst temperature is around 300–400 °C; ",[59,271,272],{},"tail-end"," SCRs sit downstream of particulate control at lower temperatures, with the trade-off of needing flue-gas reheating.",[74,275,277],{"id":276},"fouling-and-cleaning","Fouling and cleaning",[56,279,280],{},"SCR catalysts foul in two ways:",[79,282,283,298],{},[82,284,285,290,291,249,294,297],{},[59,286,287],{},[63,288,289],{"href":210},"Pluggage"," — fly ash, ",[63,292,293],{"href":97},"popcorn ash",[63,295,296],{"href":88},"large-particle ash"," wedge into the catalyst cells, blocking the gas path",[82,299,300,305],{},[59,301,302],{},[63,303,304],{"href":70},"Masking"," — a thin layer of deposit covers the active sites; gas flow continues but catalytic activity falls",[56,307,308,309,313,314,318,319,322],{},"Both reduce NOx-reduction efficiency, raise ",[63,310,312],{"href":311},"\u002Fglossary\u002Fammonia-slip","ammonia slip",", and shorten catalyst life. Cleaning options include steam ",[63,315,317],{"href":316},"\u002Fglossary\u002Fsteam-sootblower","sootblowers",", ",[63,320,321],{"href":148},"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.",[74,324,165],{"id":164},[79,326,327,333,338,343,347,351,355],{},[82,328,329],{},[63,330,332],{"href":331},"\u002Fglossary\u002Fselective-non-catalytic-reduction","Selective Non-Catalytic Reduction (SNCR)",[82,334,335],{},[63,336,337],{"href":263},"Ammonia injection grid",[82,339,340],{},[63,341,342],{"href":311},"Ammonia slip",[82,344,345],{},[63,346,186],{"href":70},[82,348,349],{},[63,350,47],{"href":210},[82,352,353],{},[63,354,192],{"href":191},[82,356,357],{},[63,358,197],{"href":148},{"title":199,"searchDepth":200,"depth":200,"links":360},[361,362,363],{"id":256,"depth":200,"text":257},{"id":276,"depth":200,"text":277},{"id":164,"depth":200,"text":165},"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.",{},[367,368,369,370,215,371,216,149],"selective-non-catalytic-reduction","denox","ammonia-injection-grid","ammonia-slip","catalyst-pluggage",{"title":373,"description":374},"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.",[376,379],{"title":377,"url":378},"Wikipedia — Selective catalytic reduction","https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FSelective_catalytic_reduction",{"title":380,"url":381},"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":386,"title":89,"aliases":387,"body":390,"category":205,"description":479,"extension":207,"meta":480,"navigation":209,"path":88,"relatedTerms":481,"seo":483,"sources":486,"stem":488,"term":177,"__hash__":489},"glossary\u002Fglossary\u002Flarge-particle-ash.md",[388,389],"LPA","large particle ash",{"type":53,"value":391,"toc":474},[392,404,408,415,419,452,454],[56,393,394,396,397,399,400,403],{},[59,395,89],{}," is fly ash significantly larger than typical particulate (above ~1 mm and sometimes up to 25 mm), produced by fragmentation of waterwall and superheater slag, agglomeration of finer ash, or thermal break-up of refractory. LPA is the dominant cause of ",[63,398,66],{"href":65}," channel ",[63,401,402],{"href":210},"pluggage"," on coal-fired utility boilers.",[74,405,407],{"id":406},"why-lpa-causes-pluggage","Why LPA causes pluggage",[56,409,410,411,414],{},"Normal fly-ash particles are smaller than typical honeycomb ",[63,412,413],{"href":191},"catalyst pitch"," (3.5–7.4 mm) and pass through. LPA particles match or exceed the pitch dimension, wedge into a channel mouth, and progressively block the cell. A single LPA particle can block one channel; clusters of LPA across the top of the catalyst face can block tens of percent of the open area.",[74,416,418],{"id":417},"mitigation","Mitigation",[79,420,421,430,436,442],{},[82,422,423,425,426,429],{},[59,424,127],{}," — coarse mesh installed upstream of the catalyst, ahead of the ",[63,427,428],{"href":263},"AIG"," or just below it, trapping particles above a set size",[82,431,432,435],{},[59,433,434],{},"Pop-up grids"," in the economiser hopper trap LPA before it reaches the SCR inlet",[82,437,438,441],{},[59,439,440],{},"Larger-pitch top guard layer"," — first catalyst layer with wider channels admits LPA which then drops through to a screen below",[82,443,444,451],{},[59,445,446,249,449],{},[63,447,448],{"href":148},"Sonic horns",[63,450,317],{"href":159}," — dislodge accumulating LPA-driven deposits between maintenance windows",[74,453,165],{"id":164},[79,455,456,460,464,468],{},[82,457,458],{},[63,459,172],{"href":65},[82,461,462],{},[63,463,98],{"href":97},[82,465,466],{},[63,467,47],{"href":210},[82,469,470],{},[63,471,473],{"href":472},"\u002Fglossary\u002Feconomiser","Economiser",{"title":199,"searchDepth":200,"depth":200,"links":475},[476,477,478],{"id":406,"depth":200,"text":407},{"id":417,"depth":200,"text":418},{"id":164,"depth":200,"text":165},"Large-particle ash (LPA) is fly ash significantly larger than typical particulate (above ~1 mm and sometimes up to 25 mm), produced by fragmentation of waterwall and superheater slag, agglomeration of finer ash, or thermal break-up of refractory. LPA is the dominant cause of SCR catalyst channel pluggage on coal-fired utility boilers.",{},[212,214,371,482],"economiser",{"title":484,"description":485},"Large-particle ash (LPA) — slag fragments that plug SCR catalysts","LPA is fly ash larger than typical (>1 mm), produced by slag fragmentation and agglomeration in the boiler. It is the leading cause of SCR catalyst channel pluggage.",[487],{"title":222,"url":223},"glossary\u002Flarge-particle-ash","uw9Bv-6YGw7P6wmfT-xY2LbAuysdWQd6SbJ-YshGDYA",{"id":491,"title":98,"aliases":492,"body":495,"category":205,"description":570,"extension":207,"meta":571,"navigation":209,"path":97,"relatedTerms":572,"seo":573,"sources":576,"stem":578,"term":98,"__hash__":579},"glossary\u002Fglossary\u002Fpopcorn-ash.md",[493,494],"popcorn fly ash","low-density ash",{"type":53,"value":496,"toc":565},[497,509,513,523,525,549,551],[56,498,499,501,502,505,506,508],{},[59,500,98],{}," is a category of ",[63,503,504],{"href":88},"large-particle ash (LPA)"," consisting of porous, low-density particles 5–25 mm in size that resemble a kernel of popped corn. The particles form during incomplete coal combustion or low-temperature slagging, particularly on sub-bituminous coal and on units operating at reduced load. The low density means the particles are easily carried by flue gas into the ",[63,507,230],{"href":65},".",[74,510,512],{"id":511},"why-popcorn-ash-matters","Why popcorn ash matters",[56,514,515,516,519,520,522],{},"Once a popcorn-ash particle enters a ",[63,517,518],{"href":191},"honeycomb catalyst"," channel, the channel is essentially blocked: the particle is too soft to break up under gas flow, too large to pass through, and too irregular to dislodge with typical ",[63,521,149],{"href":148}," energy. The result is a long-lived dead channel that reduces SCR efficiency.",[74,524,418],{"id":417},[79,526,527,533,539,544],{},[82,528,529,532],{},[59,530,531],{},"Coal blending or fuel switching"," to reduce popcorn-ash formation",[82,534,535,538],{},[59,536,537],{},"Combustion-tuning"," to raise furnace temperature and reduce porous-ash output",[82,540,541,543],{},[59,542,127],{}," upstream of the catalyst",[82,545,546,548],{},[59,547,133],{}," as first catalyst layer",[74,550,165],{"id":164},[79,552,553,557,561],{},[82,554,555],{},[63,556,177],{"href":88},[82,558,559],{},[63,560,47],{"href":210},[82,562,563],{},[63,564,172],{"href":65},{"title":199,"searchDepth":200,"depth":200,"links":566},[567,568,569],{"id":511,"depth":200,"text":512},{"id":417,"depth":200,"text":418},{"id":164,"depth":200,"text":165},"Popcorn ash is a category of large-particle ash (LPA) consisting of porous, low-density particles 5–25 mm in size that resemble a kernel of popped corn. The particles form during incomplete coal combustion or low-temperature slagging, particularly on sub-bituminous coal and on units operating at reduced load. The low density means the particles are easily carried by flue gas into the SCR.",{},[213,371,212],{"title":574,"description":575},"Popcorn ash — porous low-density particles that wedge into SCR cells","Popcorn ash is porous low-density fly-ash particles, typically 5–25 mm, formed during incomplete coal combustion. They wedge into SCR catalyst channels and resist cleaning.",[577],{"title":222,"url":223},"glossary\u002Fpopcorn-ash","ONIVUaDgbJ8YiIrW43GfjUbT3mh72uc3hfKFshfWiqg",{"id":581,"title":186,"aliases":582,"body":586,"category":205,"description":725,"extension":207,"meta":726,"navigation":209,"path":70,"relatedTerms":727,"seo":729,"sources":732,"stem":737,"term":186,"__hash__":738},"glossary\u002Fglossary\u002Fcatalyst-masking.md",[583,584,585],"SCR catalyst masking","catalyst fouling","face plugging",{"type":53,"value":587,"toc":719},[588,596,600,661,664,668,682,686,694,696],[56,589,590,592,593,595],{},[59,591,186],{}," is the deposition of a thin blanket of fine ash on the face of an ",[63,594,66],{"href":65}," that physically blocks ammonia and NOx molecules from reaching the underlying active sites. Gas continues to flow through the catalyst cells, but the active surface area is shadowed and reaction efficiency falls.",[74,597,599],{"id":598},"how-masking-differs-from-related-failure-modes","How masking differs from related failure modes",[601,602,603,619],"table",{},[604,605,606],"thead",{},[607,608,609,613,616],"tr",{},[610,611,612],"th",{},"Failure mode",[610,614,615],{},"Mechanism",[610,617,618],{},"Reversible?",[620,621,622,635,647],"tbody",{},[607,623,624,629,632],{},[625,626,627],"td",{},[59,628,304],{},[625,630,631],{},"Ash blanket on the active surface",[625,633,634],{},"Yes — cleaning restores activity",[607,636,637,641,644],{},[625,638,639],{},[63,640,289],{"href":210},[625,642,643],{},"Particles physically block catalyst channels",[625,645,646],{},"Sometimes (depends on hardness)",[607,648,649,655,658],{},[625,650,651],{},[63,652,654],{"href":653},"\u002Fglossary\u002Fcatalyst-poisoning","Poisoning",[625,656,657],{},"Chemical species bind to active sites",[625,659,660],{},"Usually no — catalyst replacement",[56,662,663],{},"Masking is the most operationally manageable of the three because it responds to cleaning.",[74,665,667],{"id":666},"what-deposits-cause-masking","What deposits cause masking",[79,669,670,673,676,679],{},[82,671,672],{},"Calcium-rich fly ash (Western US sub-bituminous, biomass)",[82,674,675],{},"Ammonium-salt films on tail-end SCRs",[82,677,678],{},"Sub-micron silica from biomass fuels",[82,680,681],{},"Iron-oxide carry-over from blast-furnace or sinter-plant SCR applications",[74,683,685],{"id":684},"sonic-horns-and-masking-control","Sonic horns and masking control",[56,687,688,690,691,693],{},[63,689,448],{"href":148}," positioned upstream of each catalyst layer continuously dislodge the developing ash blanket before it consolidates. Combined with periodic steam ",[63,692,160],{"href":159},", this two-tier cleaning typically restores catalyst activity by 10–30% within months of installation.",[74,695,165],{"id":164},[79,697,698,702,706,711,715],{},[82,699,700],{},[63,701,172],{"href":65},[82,703,704],{},[63,705,47],{"href":210},[82,707,708],{},[63,709,710],{"href":653},"Catalyst poisoning",[82,712,713],{},[63,714,192],{"href":191},[82,716,717],{},[63,718,197],{"href":148},{"title":199,"searchDepth":200,"depth":200,"links":720},[721,722,723,724],{"id":598,"depth":200,"text":599},{"id":666,"depth":200,"text":667},{"id":684,"depth":200,"text":685},{"id":164,"depth":200,"text":165},"Catalyst masking is the deposition of a thin blanket of fine ash on the face of an SCR catalyst that physically blocks ammonia and NOx molecules from reaching the underlying active sites. Gas continues to flow through the catalyst cells, but the active surface area is shadowed and reaction efficiency falls.",{},[212,371,728,216,149],"catalyst-poisoning",{"title":730,"description":731},"Catalyst masking — fine-ash blanket that suppresses SCR activity","Catalyst masking is the deposition of a thin ash layer on the SCR catalyst face that blocks ammonia and NOx from reaching the active sites. Distinct from pluggage and poisoning.",[733,734],{"title":380,"url":381},{"title":735,"url":736},"Integrated Global Services — SCR Fouling Solved","https:\u002F\u002Fintegratedglobal.com\u002Fen\u002Fcase_studies\u002Fscr-performance\u002F","glossary\u002Fcatalyst-masking","WbNY355NxnwGZ3FW-bDAalSFTSrruJrjYN-62Fgc5Ig",{"id":740,"title":192,"aliases":741,"body":744,"category":205,"description":881,"extension":207,"meta":882,"navigation":209,"path":191,"relatedTerms":883,"seo":887,"sources":890,"stem":892,"term":192,"__hash__":893},"glossary\u002Fglossary\u002Fhoneycomb-catalyst.md",[742,743],"honeycomb SCR catalyst","extruded catalyst",{"type":53,"value":745,"toc":875},[746,754,758,807,811,814,828,832,846,848],[56,747,748,749,751,752,508],{},"A ",[59,750,518],{}," is a monolithic extruded ceramic block containing a dense grid of parallel square channels through which flue gas flows. The active catalytic material — typically vanadium pentoxide and tungsten trioxide on a titanium-dioxide carrier — is incorporated into the bulk ceramic. Honeycomb is the most common form of ",[63,753,66],{"href":65},[74,755,757],{"id":756},"strengths-and-weaknesses","Strengths and weaknesses",[601,759,760,770],{},[604,761,762],{},[607,763,764,767],{},[610,765,766],{},"Strength",[610,768,769],{},"Weakness",[620,771,772,783,791,799],{},[607,773,774,777],{},[625,775,776],{},"Very high geometric surface area per unit volume",[625,778,779,780,782],{},"Channels susceptible to ",[63,781,402],{"href":210}," by ash",[607,784,785,788],{},[625,786,787],{},"Low pressure drop in clean condition",[625,789,790],{},"Brittle — handle with care during install \u002F replacement",[607,792,793,796],{},[625,794,795],{},"Mature, large supplier base",[625,797,798],{},"Channels are harder to clean than open structures",[607,800,801,804],{},[625,802,803],{},"Wide range of pitch options (3.5–7.4 mm typical)",[625,805,806],{},"Smaller pitch = more risk of pluggage",[74,808,810],{"id":809},"pitch-selection","Pitch selection",[56,812,813],{},"Pitch (centre-to-centre channel spacing) trades surface area against pluggage risk:",[79,815,816,822],{},[82,817,818,821],{},[59,819,820],{},"Smaller pitch (3.5–4.5 mm)"," — high surface area, used on clean gas streams (NGCC HRSGs, gas-fired duty)",[82,823,824,827],{},[59,825,826],{},"Larger pitch (6–7.4 mm)"," — used on dusty coal, biomass and WtE duty where pluggage risk dominates",[74,829,831],{"id":830},"layer-assembly","Layer assembly",[56,833,834,835,839,840,842,843,845],{},"Individual honeycomb blocks are loaded into a ",[63,836,838],{"href":837},"\u002Fglossary\u002Fcatalyst-layer-module","catalyst layer \u002F module"," and stacked 2–4 layers deep inside the SCR reactor. ",[63,841,448],{"href":148}," and steam ",[63,844,317],{"href":159}," are positioned between layers to keep channels clear.",[74,847,165],{"id":164},[79,849,850,854,860,866,871],{},[82,851,852],{},[63,853,172],{"href":65},[82,855,856],{},[63,857,859],{"href":858},"\u002Fglossary\u002Fplate-catalyst","Plate catalyst",[82,861,862],{},[63,863,865],{"href":864},"\u002Fglossary\u002Fcorrugated-catalyst","Corrugated catalyst",[82,867,868],{},[63,869,870],{"href":837},"Catalyst layer \u002F module",[82,872,873],{},[63,874,47],{"href":210},{"title":199,"searchDepth":200,"depth":200,"links":876},[877,878,879,880],{"id":756,"depth":200,"text":757},{"id":809,"depth":200,"text":810},{"id":830,"depth":200,"text":831},{"id":164,"depth":200,"text":165},"A honeycomb catalyst is a monolithic extruded ceramic block containing a dense grid of parallel square channels through which flue gas flows. The active catalytic material — typically vanadium pentoxide and tungsten trioxide on a titanium-dioxide carrier — is incorporated into the bulk ceramic. Honeycomb is the most common form of SCR catalyst.",{},[212,884,885,886,371],"plate-catalyst","corrugated-catalyst","catalyst-layer-module",{"title":888,"description":889},"Honeycomb catalyst — extruded SCR catalyst form factor","A honeycomb catalyst is an extruded ceramic block with parallel square channels, the most common SCR catalyst form. High surface area but susceptible to channel pluggage.",[891],{"title":377,"url":378},"glossary\u002Fhoneycomb-catalyst","_YfmRO7jrh-yc8ZLI7n3Nr5QKYo9e0uBw4yWiXy1uho",{"id":895,"title":197,"aliases":896,"body":899,"category":1098,"description":1099,"extension":207,"meta":1100,"navigation":209,"path":148,"relatedTerms":1101,"seo":1108,"sources":1111,"stem":1121,"term":197,"__hash__":1122},"glossary\u002Fglossary\u002Fsonic-horn.md",[321,897,898],"sonic cleaning horn","industrial sonic horn",{"type":53,"value":900,"toc":1091},[901,931,935,943,947,1009,1013,1049,1053,1060,1062],[56,902,748,903,906,907,911,912,318,916,318,920,318,923,249,927,508],{},[59,904,905],{},"sonic horn"," is a pneumatically-driven sound emitter that produces high-intensity, low-frequency sound waves — typically between 60 and 400 Hz at sound pressure levels of 140 to 180 dB — used to dislodge particulate fouling from inside industrial process equipment. Sonic horns are the most common form of ",[63,908,910],{"href":909},"\u002Fglossary\u002Facoustic-cleaner","acoustic cleaner"," and the default specification for cleaning ",[63,913,915],{"href":914},"\u002Fglossary\u002Felectrostatic-precipitator","ESPs",[63,917,919],{"href":918},"\u002Fglossary\u002Ffabric-filter","baghouses",[63,921,922],{"href":65},"SCR catalysts",[63,924,926],{"href":925},"\u002Fglossary\u002Fsuperheater","boiler heat-transfer surfaces",[63,928,930],{"href":929},"\u002Fglossary\u002Fhopper","hoppers and silos",[74,932,934],{"id":933},"how-a-sonic-horn-works","How a sonic horn works",[56,936,937,938,942],{},"Compressed plant air admitted through a ",[63,939,941],{"href":940},"\u002Fglossary\u002Fsolenoid-valve","solenoid valve"," drives a metal diaphragm — typically titanium or 316 stainless — into resonant oscillation at the horn's fundamental frequency. The oscillating pressure field is amplified by an exponential bell horn and projected into the vessel as a near-spherical sound wave. Particulate already deposited on internal surfaces receives an oscillating acceleration that overcomes adhesion; loosened material is then carried out with the gas flow before it can sinter, bridge or bond. Because the cleaning is acoustic and non-contact, the horn can fire while the plant is online without tube erosion, refractory damage or thermal shock.",[74,944,946],{"id":945},"key-parameters","Key parameters",[601,948,949,959],{},[604,950,951],{},[607,952,953,956],{},[610,954,955],{},"Parameter",[610,957,958],{},"Typical range",[620,960,961,969,977,985,993,1001],{},[607,962,963,966],{},[625,964,965],{},"Fundamental frequency",[625,967,968],{},"60–400 Hz",[607,970,971,974],{},[625,972,973],{},"Sound pressure level",[625,975,976],{},"140–180 dB",[607,978,979,982],{},[625,980,981],{},"Compressed-air consumption",[625,983,984],{},"8–14 Nm³\u002Fmin at 4–7 bar",[607,986,987,990],{},[625,988,989],{},"Operating temperature (with appropriate materials)",[625,991,992],{},"−40 °C to +500 °C",[607,994,995,998],{},[625,996,997],{},"Firing cycle",[625,999,1000],{},"5–15 s burst, repeated every 3–15 minutes",[607,1002,1003,1006],{},[625,1004,1005],{},"Mass",[625,1007,1008],{},"15–60 kg depending on horn size",[74,1010,1012],{"id":1011},"frequency-selection","Frequency selection",[56,1014,1015,1016,318,1020,1024,1025,318,1029,1033,1034,318,1037,1040,1041,249,1045,508],{},"Lower frequencies (60–125 Hz) project longer wavelengths and penetrate further into large open vessels — ",[63,1017,1019],{"href":1018},"\u002Fglossary\u002Fpreheater-cyclone","preheater cyclones",[63,1021,1023],{"href":1022},"\u002Fglossary\u002Frecovery-boiler","recovery-boiler superheaters",", large ",[63,1026,1028],{"href":1027},"\u002Fglossary\u002Fesp-field-bus-section","ESP fields",[63,1030,1032],{"href":1031},"\u002Fglossary\u002Fsilo","silos",". Higher frequencies (230–400 Hz) carry more energy per unit volume and suit finer dust loads in ",[63,1035,1036],{"href":918},"fabric-filter compartments",[63,1038,1039],{"href":191},"catalyst layers"," and smaller hopper geometries. See ",[63,1042,1044],{"href":1043},"\u002Fglossary\u002Flow-frequency-acoustic-cleaner","low-frequency acoustic cleaner",[63,1046,1048],{"href":1047},"\u002Fglossary\u002Fhigh-frequency-acoustic-cleaner","high-frequency acoustic cleaner",[74,1050,1052],{"id":1051},"sonic-horn-vs-steam-sootblower","Sonic horn vs steam sootblower",[56,1054,1055,1056,1059],{},"Sonic horns are increasingly specified alongside or in place of ",[63,1057,1058],{"href":316},"steam sootblowers"," because they consume no boiler-grade steam, cause no tube erosion, require almost no moving parts and can fire every few minutes without operator intervention. They are less effective on hard, fused slag than retractable steam lances, so on furnace waterwalls and high-temperature superheaters they typically complement rather than replace mechanical cleaning.",[74,1061,165],{"id":164},[79,1063,1064,1069,1074,1080,1086],{},[82,1065,1066],{},[63,1067,1068],{"href":909},"Acoustic cleaner",[82,1070,1071],{},[63,1072,1073],{"href":159},"Sonic sootblower",[82,1075,1076],{},[63,1077,1079],{"href":1078},"\u002Fglossary\u002Fbell-horn","Bell horn",[82,1081,1082],{},[63,1083,1085],{"href":1084},"\u002Fglossary\u002Fdiaphragm-horn","Diaphragm horn",[82,1087,1088],{},[63,1089,1090],{"href":1043},"Low-frequency acoustic cleaner",{"title":199,"searchDepth":200,"depth":200,"links":1092},[1093,1094,1095,1096,1097],{"id":933,"depth":200,"text":934},{"id":945,"depth":200,"text":946},{"id":1011,"depth":200,"text":1012},{"id":1051,"depth":200,"text":1052},{"id":164,"depth":200,"text":165},"core-technology","A sonic horn is a pneumatically-driven sound emitter that produces high-intensity, low-frequency sound waves — typically between 60 and 400 Hz at sound pressure levels of 140 to 180 dB — used to dislodge particulate fouling from inside industrial process equipment. Sonic horns are the most common form of acoustic cleaner and the default specification for cleaning ESPs, baghouses, SCR catalysts, boiler heat-transfer surfaces and hoppers and silos.",{},[1102,1103,1104,1105,1106,1107],"acoustic-cleaner","acoustic-cleaning-system","sonic-sootblower","bell-horn","diaphragm-horn","low-frequency-acoustic-cleaner",{"title":1109,"description":1110},"Sonic horn — definition, frequency, SPL and industrial applications","A sonic horn is a pneumatically-driven low-frequency sound emitter (typically 60–400 Hz at 140–180 dB SPL) used to dislodge particulate fouling from boilers, ESPs, baghouses and process vessels.",[1112,1115,1118],{"title":1113,"url":1114},"Power Engineering — Sonic Horns: A User's Introduction","https:\u002F\u002Fwww.power-eng.com\u002Fcoal\u002Fsonic-horns-a-userrsquos-introduction\u002F",{"title":1116,"url":1117},"Power Engineering — Tuning in to Acoustic Cleaning","https:\u002F\u002Fwww.power-eng.com\u002Fcoal\u002Ftuning-in-to-acoustic-cleaning\u002F",{"title":1119,"url":1120},"Wikipedia — Sonic soot blowers","https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FSonic_soot_blowers","glossary\u002Fsonic-horn","YzrhN0kKzqSaQo0wfn0rueNZ-V43mcg5zahqeWi3lnU",1782613751002]