[{"data":1,"prerenderedAt":1191},["ShallowReactive",2],{"site-footer-common":3,"glossary:convective-pass-backpass":45,"glossary-related:convective-pass-backpass":209},{"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":53,"category":190,"description":191,"extension":192,"meta":193,"navigation":194,"path":195,"relatedTerms":196,"seo":199,"sources":202,"stem":206,"term":207,"__hash__":208},"glossary\u002Fglossary\u002Fconvective-pass-backpass.md","Convective pass \u002F backpass",[49,50,51,52],"convective pass","backpass","boiler backpass","back pass",{"type":54,"value":55,"toc":183},"minimark",[56,88,93,96,118,133,137,145,149],[57,58,59,60,63,64,66,67,72,73,77,78,82,83,87],"p",{},"The ",[61,62,49],"strong",{}," (also ",[61,65,50],{},") is the downstream section of a boiler where heat transfer is by conduction across tube banks rather than radiation from a flame. The convective pass contains, in order of decreasing gas temperature: the finishing ",[68,69,71],"a",{"href":70},"\u002Fglossary\u002Fsuperheater","superheater",", the ",[68,74,76],{"href":75},"\u002Fglossary\u002Freheater","reheater",", the primary superheater, the ",[68,79,81],{"href":80},"\u002Fglossary\u002Feconomiser","economiser",", and finally the ",[68,84,86],{"href":85},"\u002Fglossary\u002Fair-heater","air heater",".",[89,90,92],"h2",{"id":91},"why-the-convective-pass-is-the-prime-sonic-horn-zone","Why the convective pass is the prime sonic-horn zone",[57,94,95],{},"Three reasons:",[97,98,99,106,112],"ol",{},[100,101,102,105],"li",{},[61,103,104],{},"Deposits are dry",", not molten. Ash arriving at convective surfaces has cooled below its sticking temperature; it deposits as a friable layer that acoustic energy can lift.",[100,107,108,111],{},[61,109,110],{},"Surfaces are extensive"," and partly inaccessible to retract sootblowers — perfect for non-contact cleaning.",[100,113,114,117],{},[61,115,116],{},"Heat-rate sensitivity"," is high. Every degree of approach temperature loss in the economiser or air heater translates directly into fuel cost.",[57,119,120,121,128,129,87],{},"A typical large utility boiler benefits from ",[61,122,123,124],{},"8–20 ",[68,125,127],{"href":126},"\u002Fglossary\u002Fsonic-horn","sonic horns"," distributed across the convective pass, complementing existing steam ",[68,130,132],{"href":131},"\u002Fglossary\u002Fsteam-sootblower","sootblowers",[89,134,136],{"id":135},"sequencing","Sequencing",[57,138,139,140,144],{},"Horns are fired in a programmed sequence that respects ",[68,141,143],{"href":142},"\u002Fglossary\u002Fcompressed-air","compressed-air"," supply, avoids overlapping firing on adjacent fields, and times their action between sootblower cycles to maintain continuous low-level dust release.",[89,146,148],{"id":147},"related-terms","Related terms",[150,151,152,158,163,168,173,178],"ul",{},[100,153,154],{},[68,155,157],{"href":156},"\u002Fglossary\u002Fboiler","Boiler",[100,159,160],{},[68,161,162],{"href":80},"Economiser",[100,164,165],{},[68,166,167],{"href":70},"Superheater",[100,169,170],{},[68,171,172],{"href":75},"Reheater",[100,174,175],{},[68,176,177],{"href":85},"Air heater",[100,179,180],{},[68,181,182],{"href":126},"Sonic horn",{"title":184,"searchDepth":185,"depth":185,"links":186},"",2,[187,188,189],{"id":91,"depth":185,"text":92},{"id":135,"depth":185,"text":136},{"id":147,"depth":185,"text":148},"boiler","The convective pass (also backpass) is the downstream section of a boiler where heat transfer is by conduction across tube banks rather than radiation from a flame. The convective pass contains, in order of decreasing gas temperature: the finishing superheater, the reheater, the primary superheater, the economiser, and finally the air heater.","md",{},true,"\u002Fglossary\u002Fconvective-pass-backpass",[190,81,71,76,197,198],"air-heater","sonic-horn",{"title":200,"description":201},"Convective pass (backpass) — where sonic horns earn most of their cleaning work","The convective pass is the downstream section of a boiler where heat transfer is by conduction across tube banks: superheater, reheater, economiser. The primary zone for sonic-horn cleaning.",[203],{"title":204,"url":205},"Wikipedia — Water-tube boiler","https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FWater-tube_boiler","glossary\u002Fconvective-pass-backpass","Convective pass and backpass","RDd0-n-v3frmmPFQ6GEIJ8gl1FK8dl11Q9pHezUj0Tk",[210,450,570,711,789,967],{"id":211,"title":157,"aliases":212,"body":216,"category":190,"description":430,"extension":192,"meta":431,"navigation":194,"path":156,"relatedTerms":432,"seo":438,"sources":441,"stem":448,"term":157,"__hash__":449},"glossary\u002Fglossary\u002Fboiler.md",[213,214,215],"industrial boiler","utility boiler","steam generator",{"type":54,"value":217,"toc":425},[218,245,249,367,371,395,397],[57,219,220,221,223,224,228,229,232,233,237,238,232,242,87],{},"A ",[61,222,190],{}," is a closed vessel in which fuel chemical energy is converted to steam by transferring heat into water flowing through tube banks. Industrial and utility boilers serve electricity generation, district heating, process steam, ",[68,225,227],{"href":226},"\u002Fglossary\u002Fwaste-to-energy","WtE",", ",[68,230,231],{"href":226},"biomass"," and ",[68,234,236],{"href":235},"\u002Fglossary\u002Frecovery-boiler","pulp-and-paper"," operations. All of them foul; the only variables are ",[239,240,241],"em",{},"how much",[239,243,244],{},"with what",[89,246,248],{"id":247},"boiler-families","Boiler families",[250,251,252,268],"table",{},[253,254,255],"thead",{},[256,257,258,262,265],"tr",{},[259,260,261],"th",{},"Type",[259,263,264],{},"Fuel",[259,266,267],{},"Notes",[269,270,271,286,300,314,327,341,352],"tbody",{},[256,272,273,280,283],{},[274,275,276],"td",{},[68,277,279],{"href":278},"\u002Fglossary\u002Fpc-boiler","PC boiler",[274,281,282],{},"Pulverised coal",[274,284,285],{},"Dominant utility design",[256,287,288,294,297],{},[274,289,290],{},[68,291,293],{"href":292},"\u002Fglossary\u002Fcfb-boiler","CFB boiler",[274,295,296],{},"Coal, biomass, RDF, lignite",[274,298,299],{},"Tolerates wider fuel range; lower NOx",[256,301,302,308,311],{},[274,303,304],{},[68,305,307],{"href":306},"\u002Fglossary\u002Fbfb-boiler","BFB boiler",[274,309,310],{},"Biomass, sludge, low-grade fuels",[274,312,313],{},"Bubbling fluidised bed",[256,315,316,321,324],{},[274,317,318],{},[68,319,320],{"href":235},"Recovery boiler",[274,322,323],{},"Black liquor (kraft pulp mills)",[274,325,326],{},"Combines chemicals recovery with steam",[256,328,329,335,338],{},[274,330,331],{},[68,332,334],{"href":333},"\u002Fglossary\u002Fhog-fuel-boiler-bark-boiler","Hog-fuel boiler",[274,336,337],{},"Wood waste, bark",[274,339,340],{},"Common at pulp mills as side boilers",[256,342,343,346,349],{},[274,344,345],{},"Gas \u002F oil boiler",[274,347,348],{},"Natural gas, fuel oil",[274,350,351],{},"Lower particulate, less fouling",[256,353,354,357,360],{},[274,355,356],{},"HRSG",[274,358,359],{},"Gas-turbine exhaust",[274,361,362,363],{},"See ",[68,364,366],{"href":365},"\u002Fglossary\u002Fheat-recovery-steam-generator","heat-recovery steam generator",[89,368,370],{"id":369},"where-sonic-horns-sit","Where sonic horns sit",[57,372,373,376,377,228,379,228,382,232,384,386,387,389,390,394],{},[68,374,375],{"href":126},"Sonic horns"," installed across the convective pass — between ",[68,378,81],{"href":80},[68,380,381],{"href":70},"superheaters",[68,383,76],{"href":75},[68,385,86],{"href":85}," — dislodge ash and soot continuously, supplementing or partially replacing steam ",[68,388,132],{"href":131},". The benefit shows up as ",[68,391,393],{"href":392},"\u002Fglossary\u002Fheat-rate","heat rate"," recovery, deferred outages and longer intervals between water washes.",[89,396,148],{"id":147},[150,398,399,403,407,411,417,421],{},[100,400,401],{},[68,402,279],{"href":278},[100,404,405],{},[68,406,293],{"href":292},[100,408,409],{},[68,410,320],{"href":235},[100,412,413],{},[68,414,416],{"href":415},"\u002Fglossary\u002Fwaterwall","Waterwall",[100,418,419],{},[68,420,162],{"href":80},[100,422,423],{},[68,424,182],{"href":126},{"title":184,"searchDepth":185,"depth":185,"links":426},[427,428,429],{"id":247,"depth":185,"text":248},{"id":369,"depth":185,"text":370},{"id":147,"depth":185,"text":148},"A boiler is a closed vessel in which fuel chemical energy is converted to steam by transferring heat into water flowing through tube banks. Industrial and utility boilers serve electricity generation, district heating, process steam, WtE, biomass and pulp-and-paper operations. All of them foul; the only variables are how much and with what.",{},[433,434,435,436,437,81,71,197,198],"pc-boiler","cfb-boiler","bfb-boiler","recovery-boiler","waterwall",{"title":439,"description":440},"Boiler — industrial steam generator types and acoustic-cleaning needs","A boiler is a vessel that converts fuel chemical energy into steam by heating water. Coal-fired, biomass, oil, gas and recovery boilers all foul; sonic horns clean heat-transfer surfaces.",[442,445],{"title":443,"url":444},"Wikipedia — Boiler","https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FBoiler",{"title":446,"url":447},"Babcock & Wilcox — Sootblower and Boiler Cleaning Terminology","https:\u002F\u002Fwww.babcock.com\u002Fhome\u002Fabout\u002Fresources\u002Flearning-center\u002Fsootblower-and-boiler-cleaning-terminology-principles-and-applications","glossary\u002Fboiler","pamAnZGo_UeIedDHhYrfv0nP3GCXkNTGi0a197n4b5Q",{"id":451,"title":162,"aliases":452,"body":455,"category":190,"description":556,"extension":192,"meta":557,"navigation":194,"path":80,"relatedTerms":558,"seo":561,"sources":564,"stem":568,"term":162,"__hash__":569},"glossary\u002Fglossary\u002Feconomiser.md",[453,454],"economizer","feedwater economiser",{"type":54,"value":456,"toc":550},[457,474,478,481,498,501,505,510,514,522,524],[57,458,459,460,462,463,465,466,468,469,471,472,87],{},"An ",[61,461,81],{}," is the tube bank in a boiler's ",[68,464,49],{"href":195}," that recovers residual heat from the flue gas by preheating boiler feedwater. It sits downstream of the ",[68,467,76],{"href":75}," and upstream of the ",[68,470,86],{"href":85},"; economiser performance directly affects boiler ",[68,473,393],{"href":392},[89,475,477],{"id":476},"fouling","Fouling",[57,479,480],{},"Two failure modes dominate:",[150,482,483,489],{},[100,484,485,488],{},[61,486,487],{},"Ash bridging"," between tubes — gas can no longer pass freely; ΔP across the economiser rises",[100,490,491,497],{},[61,492,493],{},[68,494,496],{"href":495},"\u002Fglossary\u002Flarge-particle-ash","Large-particle ash"," dropping out of the gas stream onto economiser hoppers — bridges and pluggage in the hopper itself",[57,499,500],{},"The first reduces gas-side heat transfer and forces gas channelling around the blocked area; the second causes hopper extraction to fail and back-pressures the gas path.",[89,502,504],{"id":503},"sonic-horn-duty","Sonic-horn duty",[57,506,507,509],{},[68,508,375],{"href":126}," mounted on the economiser shell and hopper are particularly effective because economiser deposits are dry, friable and respond well to acoustic dislodging. Plants commonly report 1–2% boiler-efficiency recovery after horn installation on heavily-fouled economisers.",[89,511,513],{"id":512},"economiser-scr-adjacency","Economiser-SCR adjacency",[57,515,516,517,521],{},"On units with an upstream ",[68,518,520],{"href":519},"\u002Fglossary\u002Fhigh-dust-low-dust-tail-end-scr","high-dust SCR",", the economiser receives the same large-particle ash that the SCR is designed against. LPA screens between SCR and economiser are common; sonic horns help keep both surfaces clean.",[89,523,148],{"id":147},[150,525,526,530,534,538,542,546],{},[100,527,528],{},[68,529,157],{"href":156},[100,531,532],{},[68,533,47],{"href":195},[100,535,536],{},[68,537,167],{"href":70},[100,539,540],{},[68,541,177],{"href":85},[100,543,544],{},[68,545,496],{"href":495},[100,547,548],{},[68,549,182],{"href":126},{"title":184,"searchDepth":185,"depth":185,"links":551},[552,553,554,555],{"id":476,"depth":185,"text":477},{"id":503,"depth":185,"text":504},{"id":512,"depth":185,"text":513},{"id":147,"depth":185,"text":148},"An economiser is the tube bank in a boiler's convective pass that recovers residual heat from the flue gas by preheating boiler feedwater. It sits downstream of the reheater and upstream of the air heater; economiser performance directly affects boiler heat rate.",{},[190,559,71,197,560,198],"convective-pass-backpass","large-particle-ash",{"title":562,"description":563},"Economiser — final tube bank that preheats feedwater with flue-gas heat","An economiser is the final tube bank in a boiler's convective pass that recovers heat from the flue gas by preheating feedwater. Ash bridging in the economiser is a routine cleaning challenge.",[565],{"title":566,"url":567},"Wikipedia — Economizer","https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FEconomizer","glossary\u002Feconomiser","kh4Q3Eo9CNl35_b843VUXSI8fDZuiLZqLyB__NSzVH4",{"id":571,"title":167,"aliases":572,"body":576,"category":190,"description":697,"extension":192,"meta":698,"navigation":194,"path":70,"relatedTerms":699,"seo":702,"sources":705,"stem":709,"term":167,"__hash__":710},"glossary\u002Fglossary\u002Fsuperheater.md",[381,573,574,575],"primary superheater","secondary superheater","finishing superheater",{"type":54,"value":577,"toc":692},[578,586,588,624,628,636,659,662,664],[57,579,220,580,582,583,585],{},[61,581,71],{}," is a tube bank in a boiler's ",[68,584,49],{"href":195}," that raises the steam temperature beyond its saturation point using residual heat from the flue gas. Most utility boilers have at least two superheater stages: a primary superheater (cooler gas) and a secondary or finishing superheater (closest to the furnace, hottest gas).",[89,587,477],{"id":476},[150,589,590,604,610],{},[100,591,592,598,599,603],{},[61,593,594],{},[68,595,597],{"href":596},"\u002Fglossary\u002Fslagging","Slagging"," on the finishing superheater — semi-molten ash from the ",[68,600,602],{"href":601},"\u002Fglossary\u002Ffurnace","furnace"," deposits on the hottest tubes",[100,605,606,609],{},[61,607,608],{},"Bonded ash"," on the primary superheater — drier deposits that sinter under sustained temperature",[100,611,612,615,616,228,618,232,620,623],{},[61,613,614],{},"Sodium \u002F potassium-rich deposits"," on ",[68,617,231],{"href":226},[68,619,227],{"href":226},[68,621,622],{"href":235},"recovery boilers"," — sticky, low-melting, aggressive",[89,625,627],{"id":626},"cleaning","Cleaning",[57,629,630,631,232,633,635],{},"Steam ",[68,632,132],{"href":131},[68,634,127],{"href":126}," work together:",[150,637,638,641,649],{},[100,639,640],{},"Sootblowers attack hard slag on the finishing superheater",[100,642,643,644,648],{},"Sonic horns (",[68,645,647],{"href":646},"\u002Fglossary\u002Flow-frequency-acoustic-cleaner","60–125 Hz",") keep dry ash from consolidating on the primary superheater and convective superheater",[100,650,651,655,656,658],{},[68,652,654],{"href":653},"\u002Fglossary\u002Finfrasonic-cleaner","Infrasonic cleaners"," below 30 Hz are used on deep ",[68,657,436],{"href":235}," superheater cavities",[57,660,661],{},"The combination extends the interval between major water-washes and reduces steam-attemperation requirements that mask deteriorating heat transfer.",[89,663,148],{"id":147},[150,665,666,670,674,678,682,686],{},[100,667,668],{},[68,669,157],{"href":156},[100,671,672],{},[68,673,47],{"href":195},[100,675,676],{},[68,677,172],{"href":75},[100,679,680],{},[68,681,597],{"href":596},[100,683,684],{},[68,685,182],{"href":126},[100,687,688],{},[68,689,691],{"href":690},"\u002Fglossary\u002Fsonic-sootblower","Sonic sootblower",{"title":184,"searchDepth":185,"depth":185,"links":693},[694,695,696],{"id":476,"depth":185,"text":477},{"id":626,"depth":185,"text":627},{"id":147,"depth":185,"text":148},"A superheater is a tube bank in a boiler's convective pass that raises the steam temperature beyond its saturation point using residual heat from the flue gas. Most utility boilers have at least two superheater stages: a primary superheater (cooler gas) and a secondary or finishing superheater (closest to the furnace, hottest gas).",{},[190,559,76,700,198,701],"slagging","sonic-sootblower",{"title":703,"description":704},"Superheater — boiler tube bank that raises steam temperature beyond saturation","A superheater is a tube bank that raises steam temperature beyond the saturation point using flue-gas heat. Sticky alkali ash and slag deposits are the dominant fouling concerns.",[706],{"title":707,"url":708},"Wikipedia — Superheater","https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FSuperheater","glossary\u002Fsuperheater","hYVXyyVmlWCU3AXfAl0l3YAhHpWty_akkDsBJGC_NDs",{"id":712,"title":172,"aliases":713,"body":716,"category":190,"description":779,"extension":192,"meta":780,"navigation":194,"path":75,"relatedTerms":781,"seo":782,"sources":785,"stem":787,"term":172,"__hash__":788},"glossary\u002Fglossary\u002Freheater.md",[714,715],"reheaters","reheat section",{"type":54,"value":717,"toc":773},[718,725,729,735,737,740,742,753,755],[57,719,220,720,582,722,724],{},[61,721,76],{},[68,723,49],{"href":195}," that re-superheats steam returning from the high-pressure (HP) turbine before it enters the intermediate-pressure (IP) turbine. Reheat improves overall plant efficiency and reduces steam moisture content in the LP turbine stages.",[89,726,728],{"id":727},"where-it-sits","Where it sits",[57,730,731,732,734],{},"In a typical utility-boiler convective pass, the reheater sits between the secondary ",[68,733,71],{"href":70}," and the primary superheater, in a temperature range that recovers heat efficiently without exceeding tube-metal limits. Some boilers have two reheat stages.",[89,736,477],{"id":476},[57,738,739],{},"Reheater fouling follows the same pattern as the convective superheater: bonded ash on tube surfaces, occasional slag bridging in extreme cases. Outlet steam-temperature deviation is a leading symptom — falling reheat outlet temperature signals fouling reducing heat absorption.",[89,741,627],{"id":626},[57,743,744,746,747,750,751,87],{},[68,745,375],{"href":126}," are well suited to reheater cleaning because the deposits are predominantly dry. Combined with periodic steam ",[68,748,749],{"href":690},"sootblowing",", they maintain reheater outlet temperature and protect the unit's ",[68,752,393],{"href":392},[89,754,148],{"id":147},[150,756,757,761,765,769],{},[100,758,759],{},[68,760,157],{"href":156},[100,762,763],{},[68,764,167],{"href":70},[100,766,767],{},[68,768,47],{"href":195},[100,770,771],{},[68,772,182],{"href":126},{"title":184,"searchDepth":185,"depth":185,"links":774},[775,776,777,778],{"id":727,"depth":185,"text":728},{"id":476,"depth":185,"text":477},{"id":626,"depth":185,"text":627},{"id":147,"depth":185,"text":148},"A reheater is a tube bank in a boiler's convective pass that re-superheats steam returning from the high-pressure (HP) turbine before it enters the intermediate-pressure (IP) turbine. Reheat improves overall plant efficiency and reduces steam moisture content in the LP turbine stages.",{},[190,71,559,198],{"title":783,"description":784},"Reheater — boiler tube bank that re-superheats partially-expanded steam","A reheater is a tube bank in the boiler's convective pass that re-superheats steam returning from the HP turbine before it enters the IP turbine.",[786],{"title":443,"url":444},"glossary\u002Freheater","XRFivXVrBNHuAf0pa3jm4fF6BiJP2Z3jS5gz0vyyDt0",{"id":790,"title":791,"aliases":792,"body":796,"category":190,"description":951,"extension":192,"meta":952,"navigation":194,"path":85,"relatedTerms":953,"seo":958,"sources":961,"stem":965,"term":177,"__hash__":966},"glossary\u002Fglossary\u002Fair-heater.md","Air heater (APH)",[793,794,795],"air preheater","APH","air heaters",{"type":54,"value":797,"toc":945},[798,809,813,856,860,873,903,907,913,915],[57,799,459,800,802,803,805,806,808],{},[61,801,86],{}," — also called an ",[61,804,793],{}," (APH) — is the final heat-recovery device in a boiler's ",[68,807,49],{"href":195},", recovering low-grade heat from cooling flue gas to preheat the combustion air. APHs lift overall boiler efficiency by 5–10 percentage points and are critical to heat-rate performance.",[89,810,812],{"id":811},"aph-types","APH types",[250,814,815,824],{},[253,816,817],{},[256,818,819,821],{},[259,820,261],{},[259,822,823],{},"Description",[269,825,826,837,848],{},[256,827,828,834],{},[274,829,830],{},[68,831,833],{"href":832},"\u002Fglossary\u002Fljungstrom-air-preheater","Ljungström \u002F regenerative",[274,835,836],{},"Rotating matrix of heat-exchange baskets cycling between gas and air sides",[256,838,839,845],{},[274,840,841],{},[68,842,844],{"href":843},"\u002Fglossary\u002Ftubular-air-preheater","Tubular",[274,846,847],{},"Fixed tube bundle with flue gas through tubes, air around them",[256,849,850,853],{},[274,851,852],{},"Plate-type",[274,854,855],{},"Cross-flow plate exchanger; smaller industrial duty",[89,857,859],{"id":858},"the-cold-end-problem","The cold-end problem",[57,861,862,863,867,868,872],{},"The APH cold end is the coolest point in the flue-gas path before the ",[68,864,866],{"href":865},"\u002Fglossary\u002Felectrostatic-precipitator","ESP"," \u002F ",[68,869,871],{"href":870},"\u002Fglossary\u002Fbaghouse","baghouse",". Two related failure modes dominate:",[150,874,875,889],{},[100,876,877,883,884,888],{},[61,878,879],{},[68,880,882],{"href":881},"\u002Fglossary\u002Fammonium-bisulphate","Ammonium bisulphate (ABS)"," fouling on boilers with upstream ",[68,885,887],{"href":886},"\u002Fglossary\u002Fselective-catalytic-reduction","SCR",": sticky deposits plug Ljungström baskets and tubular APH tubes",[100,890,891,897,898,902],{},[61,892,893],{},[68,894,896],{"href":895},"\u002Fglossary\u002Fcold-end-corrosion-dew-point-corrosion","Cold-end corrosion"," below the ",[68,899,901],{"href":900},"\u002Fglossary\u002Facid-dew-point","acid dew point"," — sulphuric acid condenses and attacks baskets and tubes",[89,904,906],{"id":905},"why-sonic-horns-are-routinely-specified-on-aphs","Why sonic horns are routinely specified on APHs",[57,908,909,910,912],{},"ABS fouling is the single most common reason plants install ",[68,911,127],{"href":126}," on the cold end. Continuous low-amplitude vibration prevents ABS from consolidating between water-wash campaigns, extending the campaign interval from quarterly to annual and avoiding capacity-derate excursions.",[89,914,148],{"id":147},[150,916,917,921,926,931,936,941],{},[100,918,919],{},[68,920,157],{"href":156},[100,922,923],{},[68,924,925],{"href":832},"Ljungström air preheater",[100,927,928],{},[68,929,930],{"href":843},"Tubular air preheater",[100,932,933],{},[68,934,935],{"href":881},"Ammonium bisulphate",[100,937,938],{},[68,939,940],{"href":895},"Cold-end corrosion \u002F dew-point corrosion",[100,942,943],{},[68,944,182],{"href":126},{"title":184,"searchDepth":185,"depth":185,"links":946},[947,948,949,950],{"id":811,"depth":185,"text":812},{"id":858,"depth":185,"text":859},{"id":905,"depth":185,"text":906},{"id":147,"depth":185,"text":148},"An air heater — also called an air preheater (APH) — is the final heat-recovery device in a boiler's convective pass, recovering low-grade heat from cooling flue gas to preheat the combustion air. APHs lift overall boiler efficiency by 5–10 percentage points and are critical to heat-rate performance.",{},[190,954,955,956,957,198],"ljungstrom-air-preheater","tubular-air-preheater","ammonium-bisulphate","cold-end-corrosion-dew-point-corrosion",{"title":959,"description":960},"Air heater (APH) — final flue-gas heat-recovery device before the stack","An air heater (also air preheater, APH) recovers low-grade heat from flue gas to preheat combustion air. Cold-end fouling and corrosion are the dominant operational challenges.",[962],{"title":963,"url":964},"Wikipedia — Air preheater","https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FAir_preheater","glossary\u002Fair-heater","3pBQ2ZyiQ7VOKuf9rxsx43EFarkhgykVhd2amXg0TMY",{"id":968,"title":182,"aliases":969,"body":972,"category":1167,"description":1168,"extension":192,"meta":1169,"navigation":194,"path":126,"relatedTerms":1170,"seo":1176,"sources":1179,"stem":1189,"term":182,"__hash__":1190},"glossary\u002Fglossary\u002Fsonic-horn.md",[127,970,971],"sonic cleaning horn","industrial sonic horn",{"type":54,"value":973,"toc":1160},[974,1002,1006,1014,1018,1080,1084,1119,1123,1130,1132],[57,975,220,976,979,980,984,985,228,988,228,992,228,995,232,998,87],{},[61,977,978],{},"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 ",[68,981,983],{"href":982},"\u002Fglossary\u002Facoustic-cleaner","acoustic cleaner"," and the default specification for cleaning ",[68,986,987],{"href":865},"ESPs",[68,989,991],{"href":990},"\u002Fglossary\u002Ffabric-filter","baghouses",[68,993,994],{"href":886},"SCR catalysts",[68,996,997],{"href":70},"boiler heat-transfer surfaces",[68,999,1001],{"href":1000},"\u002Fglossary\u002Fhopper","hoppers and silos",[89,1003,1005],{"id":1004},"how-a-sonic-horn-works","How a sonic horn works",[57,1007,1008,1009,1013],{},"Compressed plant air admitted through a ",[68,1010,1012],{"href":1011},"\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.",[89,1015,1017],{"id":1016},"key-parameters","Key parameters",[250,1019,1020,1030],{},[253,1021,1022],{},[256,1023,1024,1027],{},[259,1025,1026],{},"Parameter",[259,1028,1029],{},"Typical range",[269,1031,1032,1040,1048,1056,1064,1072],{},[256,1033,1034,1037],{},[274,1035,1036],{},"Fundamental frequency",[274,1038,1039],{},"60–400 Hz",[256,1041,1042,1045],{},[274,1043,1044],{},"Sound pressure level",[274,1046,1047],{},"140–180 dB",[256,1049,1050,1053],{},[274,1051,1052],{},"Compressed-air consumption",[274,1054,1055],{},"8–14 Nm³\u002Fmin at 4–7 bar",[256,1057,1058,1061],{},[274,1059,1060],{},"Operating temperature (with appropriate materials)",[274,1062,1063],{},"−40 °C to +500 °C",[256,1065,1066,1069],{},[274,1067,1068],{},"Firing cycle",[274,1070,1071],{},"5–15 s burst, repeated every 3–15 minutes",[256,1073,1074,1077],{},[274,1075,1076],{},"Mass",[274,1078,1079],{},"15–60 kg depending on horn size",[89,1081,1083],{"id":1082},"frequency-selection","Frequency selection",[57,1085,1086,1087,228,1091,1094,1095,228,1099,1103,1104,228,1107,1111,1112,232,1115,87],{},"Lower frequencies (60–125 Hz) project longer wavelengths and penetrate further into large open vessels — ",[68,1088,1090],{"href":1089},"\u002Fglossary\u002Fpreheater-cyclone","preheater cyclones",[68,1092,1093],{"href":235},"recovery-boiler superheaters",", large ",[68,1096,1098],{"href":1097},"\u002Fglossary\u002Fesp-field-bus-section","ESP fields",[68,1100,1102],{"href":1101},"\u002Fglossary\u002Fsilo","silos",". Higher frequencies (230–400 Hz) carry more energy per unit volume and suit finer dust loads in ",[68,1105,1106],{"href":990},"fabric-filter compartments",[68,1108,1110],{"href":1109},"\u002Fglossary\u002Fhoneycomb-catalyst","catalyst layers"," and smaller hopper geometries. See ",[68,1113,1114],{"href":646},"low-frequency acoustic cleaner",[68,1116,1118],{"href":1117},"\u002Fglossary\u002Fhigh-frequency-acoustic-cleaner","high-frequency acoustic cleaner",[89,1120,1122],{"id":1121},"sonic-horn-vs-steam-sootblower","Sonic horn vs steam sootblower",[57,1124,1125,1126,1129],{},"Sonic horns are increasingly specified alongside or in place of ",[68,1127,1128],{"href":131},"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.",[89,1131,148],{"id":147},[150,1133,1134,1139,1143,1149,1155],{},[100,1135,1136],{},[68,1137,1138],{"href":982},"Acoustic cleaner",[100,1140,1141],{},[68,1142,691],{"href":690},[100,1144,1145],{},[68,1146,1148],{"href":1147},"\u002Fglossary\u002Fbell-horn","Bell horn",[100,1150,1151],{},[68,1152,1154],{"href":1153},"\u002Fglossary\u002Fdiaphragm-horn","Diaphragm horn",[100,1156,1157],{},[68,1158,1159],{"href":646},"Low-frequency acoustic cleaner",{"title":184,"searchDepth":185,"depth":185,"links":1161},[1162,1163,1164,1165,1166],{"id":1004,"depth":185,"text":1005},{"id":1016,"depth":185,"text":1017},{"id":1082,"depth":185,"text":1083},{"id":1121,"depth":185,"text":1122},{"id":147,"depth":185,"text":148},"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.",{},[1171,1172,701,1173,1174,1175],"acoustic-cleaner","acoustic-cleaning-system","bell-horn","diaphragm-horn","low-frequency-acoustic-cleaner",{"title":1177,"description":1178},"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.",[1180,1183,1186],{"title":1181,"url":1182},"Power Engineering — Sonic Horns: A User's Introduction","https:\u002F\u002Fwww.power-eng.com\u002Fcoal\u002Fsonic-horns-a-userrsquos-introduction\u002F",{"title":1184,"url":1185},"Power Engineering — Tuning in to Acoustic Cleaning","https:\u002F\u002Fwww.power-eng.com\u002Fcoal\u002Ftuning-in-to-acoustic-cleaning\u002F",{"title":1187,"url":1188},"Wikipedia — Sonic soot blowers","https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FSonic_soot_blowers","glossary\u002Fsonic-horn","YzrhN0kKzqSaQo0wfn0rueNZ-V43mcg5zahqeWi3lnU",1782613724464]