[{"data":1,"prerenderedAt":713},["ShallowReactive",2],{"site-footer-common":3,"glossary:tubular-air-preheater":45,"glossary-related:tubular-air-preheater":188},{"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":51,"category":169,"description":170,"extension":171,"meta":172,"navigation":173,"path":174,"relatedTerms":175,"seo":179,"sources":182,"stem":186,"term":47,"__hash__":187},"glossary\u002Fglossary\u002Ftubular-air-preheater.md","Tubular air preheater",[49,50],"tubular APH","TAPH",{"type":52,"value":53,"toc":162},"minimark",[54,74,79,107,111,119,141,145],[55,56,57,58,62,63,68,69,73],"p",{},"A ",[59,60,61],"strong",{},"tubular air preheater (TAPH)"," is a fixed shell-and-tube ",[64,65,67],"a",{"href":66},"\u002Fglossary\u002Fair-heater","air heater"," in which flue gas flows inside vertical tubes and combustion air flows around the outside in cross-flow or counter-flow. The construction is mechanically simpler than the rotating ",[64,70,72],{"href":71},"\u002Fglossary\u002Fljungstrom-air-preheater","Ljungström"," design but offers less surface area per unit volume.",[75,76,78],"h2",{"id":77},"where-taphs-are-used","Where TAPHs are used",[80,81,82,86,93,104],"ul",{},[83,84,85],"li",{},"Smaller industrial boilers",[83,87,88,92],{},[64,89,91],{"href":90},"\u002Fglossary\u002Frecovery-boiler","Recovery boilers"," at pulp mills",[83,94,95,99,100,103],{},[64,96,98],{"href":97},"\u002Fglossary\u002Fwaste-to-energy","WtE"," and ",[64,101,102],{"href":97},"biomass"," duty where rotating-basket Ljungströms are vulnerable to sticky-ash agglomerates",[83,105,106],{},"Some retrofit installations where the existing Ljungström has reached end of life",[75,108,110],{"id":109},"fouling","Fouling",[55,112,113,114,118],{},"Tubular APH tubes plug from the inside if flue gas carries sticky ash or ",[64,115,117],{"href":116},"\u002Fglossary\u002Fammonium-bisulphate","ammonium bisulphate",". Cleaning options:",[80,120,121,128,135,138],{},[83,122,123,124],{},"Steam ",[64,125,127],{"href":126},"\u002Fglossary\u002Fsteam-sootblower","sootblowing",[83,129,130,134],{},[64,131,133],{"href":132},"\u002Fglossary\u002Fsonic-horn","Sonic horns"," mounted at the tube-bundle gas inlet",[83,136,137],{},"Off-line high-pressure water washing",[83,139,140],{},"Manual rodding during major outages",[75,142,144],{"id":143},"related-terms","Related terms",[80,146,147,152,157],{},[83,148,149],{},[64,150,151],{"href":66},"Air heater",[83,153,154],{},[64,155,156],{"href":71},"Ljungström air preheater",[83,158,159],{},[64,160,161],{"href":132},"Sonic horn",{"title":163,"searchDepth":164,"depth":164,"links":165},"",2,[166,167,168],{"id":77,"depth":164,"text":78},{"id":109,"depth":164,"text":110},{"id":143,"depth":164,"text":144},"boiler","A tubular air preheater (TAPH) is a fixed shell-and-tube air heater in which flue gas flows inside vertical tubes and combustion air flows around the outside in cross-flow or counter-flow. The construction is mechanically simpler than the rotating Ljungström design but offers less surface area per unit volume.","md",{},true,"\u002Fglossary\u002Ftubular-air-preheater",[176,177,178],"air-heater","ljungstrom-air-preheater","sonic-horn",{"title":180,"description":181},"Tubular air preheater — fixed-tube alternative to Ljungström APH","A tubular air preheater is a fixed tube bundle with flue gas through the tubes and combustion air around them. Common on smaller industrial boilers and on retrofit duty.",[183],{"title":184,"url":185},"Wikipedia — Air preheater","https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FAir_preheater","glossary\u002Ftubular-air-preheater","fiT3hi_aRSHyGbj0N07lIgp2BLoesBLQdXq4KbK_7sQ",[189,372,482],{"id":190,"title":191,"aliases":192,"body":196,"category":169,"description":359,"extension":171,"meta":360,"navigation":173,"path":66,"relatedTerms":361,"seo":365,"sources":368,"stem":370,"term":151,"__hash__":371},"glossary\u002Fglossary\u002Fair-heater.md","Air heater (APH)",[193,194,195],"air preheater","APH","air heaters",{"type":52,"value":197,"toc":353},[198,212,216,264,268,281,310,314,321,323],[55,199,200,201,203,204,206,207,211],{},"An ",[59,202,67],{}," — also called an ",[59,205,193],{}," (APH) — is the final heat-recovery device in a boiler's ",[64,208,210],{"href":209},"\u002Fglossary\u002Fconvective-pass-backpass","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.",[75,213,215],{"id":214},"aph-types","APH types",[217,218,219,232],"table",{},[220,221,222],"thead",{},[223,224,225,229],"tr",{},[226,227,228],"th",{},"Type",[226,230,231],{},"Description",[233,234,235,246,256],"tbody",{},[223,236,237,243],{},[238,239,240],"td",{},[64,241,242],{"href":71},"Ljungström \u002F regenerative",[238,244,245],{},"Rotating matrix of heat-exchange baskets cycling between gas and air sides",[223,247,248,253],{},[238,249,250],{},[64,251,252],{"href":174},"Tubular",[238,254,255],{},"Fixed tube bundle with flue gas through tubes, air around them",[223,257,258,261],{},[238,259,260],{},"Plate-type",[238,262,263],{},"Cross-flow plate exchanger; smaller industrial duty",[75,265,267],{"id":266},"the-cold-end-problem","The cold-end problem",[55,269,270,271,275,276,280],{},"The APH cold end is the coolest point in the flue-gas path before the ",[64,272,274],{"href":273},"\u002Fglossary\u002Felectrostatic-precipitator","ESP"," \u002F ",[64,277,279],{"href":278},"\u002Fglossary\u002Fbaghouse","baghouse",". Two related failure modes dominate:",[80,282,283,296],{},[83,284,285,290,291,295],{},[59,286,287],{},[64,288,289],{"href":116},"Ammonium bisulphate (ABS)"," fouling on boilers with upstream ",[64,292,294],{"href":293},"\u002Fglossary\u002Fselective-catalytic-reduction","SCR",": sticky deposits plug Ljungström baskets and tubular APH tubes",[83,297,298,304,305,309],{},[59,299,300],{},[64,301,303],{"href":302},"\u002Fglossary\u002Fcold-end-corrosion-dew-point-corrosion","Cold-end corrosion"," below the ",[64,306,308],{"href":307},"\u002Fglossary\u002Facid-dew-point","acid dew point"," — sulphuric acid condenses and attacks baskets and tubes",[75,311,313],{"id":312},"why-sonic-horns-are-routinely-specified-on-aphs","Why sonic horns are routinely specified on APHs",[55,315,316,317,320],{},"ABS fouling is the single most common reason plants install ",[64,318,319],{"href":132},"sonic horns"," 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.",[75,322,144],{"id":143},[80,324,325,331,335,339,344,349],{},[83,326,327],{},[64,328,330],{"href":329},"\u002Fglossary\u002Fboiler","Boiler",[83,332,333],{},[64,334,156],{"href":71},[83,336,337],{},[64,338,47],{"href":174},[83,340,341],{},[64,342,343],{"href":116},"Ammonium bisulphate",[83,345,346],{},[64,347,348],{"href":302},"Cold-end corrosion \u002F dew-point corrosion",[83,350,351],{},[64,352,161],{"href":132},{"title":163,"searchDepth":164,"depth":164,"links":354},[355,356,357,358],{"id":214,"depth":164,"text":215},{"id":266,"depth":164,"text":267},{"id":312,"depth":164,"text":313},{"id":143,"depth":164,"text":144},"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.",{},[169,177,362,363,364,178],"tubular-air-preheater","ammonium-bisulphate","cold-end-corrosion-dew-point-corrosion",{"title":366,"description":367},"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.",[369],{"title":184,"url":185},"glossary\u002Fair-heater","3pBQ2ZyiQ7VOKuf9rxsx43EFarkhgykVhd2amXg0TMY",{"id":373,"title":156,"aliases":374,"body":378,"category":169,"description":470,"extension":171,"meta":471,"navigation":173,"path":71,"relatedTerms":472,"seo":473,"sources":476,"stem":480,"term":156,"__hash__":481},"glossary\u002Fglossary\u002Fljungstrom-air-preheater.md",[375,376,377],"Ljungstrom APH","regenerative air preheater","rotary APH",{"type":52,"value":379,"toc":464},[380,389,393,396,420,424,435,439,444,446],[55,381,382,383,385,386,388],{},"The ",[59,384,156],{}," is a regenerative-type ",[64,387,67],{"href":66}," using a rotating matrix of heat-exchange baskets that cycle between the flue-gas and combustion-air sides of the boiler. As the matrix rotates (typically at 1–3 rpm), each basket alternately absorbs heat from the hot flue gas and releases it to the cold combustion air. Patented by Frederik Ljungström in 1920, it is the dominant utility-scale APH design worldwide.",[75,390,392],{"id":391},"basket-arrangement","Basket arrangement",[55,394,395],{},"A typical Ljungström has hot-end, intermediate and cold-end basket layers, each chosen for its operating-temperature band:",[80,397,398,404,410],{},[83,399,400,403],{},[59,401,402],{},"Hot end"," — flat, robust, large-pitch baskets",[83,405,406,409],{},[59,407,408],{},"Intermediate"," — moderate-pitch",[83,411,412,415,416],{},[59,413,414],{},"Cold end"," — small-pitch, high-surface-area baskets — ",[417,418,419],"em",{},"and the most fouling-prone",[75,421,423],{"id":422},"cold-end-fouling","Cold-end fouling",[55,425,426,427,430,431,434],{},"The cold-end baskets are the smallest and most easily plugged. Two failure modes dominate: ",[64,428,429],{"href":116},"ammonium-bisulphate (ABS)"," deposition on SCR-equipped units, and ",[64,432,433],{"href":302},"cold-end corrosion"," below the acid dew point. Fouled cold-end baskets raise APH ΔP, derate the ID fan, and ultimately force a full water-wash campaign.",[75,436,438],{"id":437},"cleaning","Cleaning",[55,440,441,443],{},[64,442,133],{"href":132}," mounted on the cold-end gas side keep baskets clear between periodic steam-sootblower passes, extending the interval to full water-wash from quarterly to annual on many units.",[75,445,144],{"id":143},[80,447,448,452,456,460],{},[83,449,450],{},[64,451,151],{"href":66},[83,453,454],{},[64,455,47],{"href":174},[83,457,458],{},[64,459,343],{"href":116},[83,461,462],{},[64,463,161],{"href":132},{"title":163,"searchDepth":164,"depth":164,"links":465},[466,467,468,469],{"id":391,"depth":164,"text":392},{"id":422,"depth":164,"text":423},{"id":437,"depth":164,"text":438},{"id":143,"depth":164,"text":144},"The Ljungström air preheater is a regenerative-type air heater using a rotating matrix of heat-exchange baskets that cycle between the flue-gas and combustion-air sides of the boiler. As the matrix rotates (typically at 1–3 rpm), each basket alternately absorbs heat from the hot flue gas and releases it to the cold combustion air. Patented by Frederik Ljungström in 1920, it is the dominant utility-scale APH design worldwide.",{},[176,362,363,178],{"title":474,"description":475},"Ljungström air preheater — rotating-basket regenerative APH design","A Ljungström air preheater uses a rotating matrix of heat-exchange baskets that cycle between the flue-gas and combustion-air sides. The dominant utility APH design worldwide.",[477],{"title":478,"url":479},"Wikipedia — Ljungström air preheater","https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FLjungstr%C3%B6m_air_preheater","glossary\u002Fljungstrom-air-preheater","GkwHkh96PaXY9tkG7lFEJIaZkCSSagWSxoQsQnFXtBE",{"id":483,"title":161,"aliases":484,"body":487,"category":688,"description":689,"extension":171,"meta":690,"navigation":173,"path":132,"relatedTerms":691,"seo":698,"sources":701,"stem":711,"term":161,"__hash__":712},"glossary\u002Fglossary\u002Fsonic-horn.md",[319,485,486],"sonic cleaning horn","industrial sonic horn",{"type":52,"value":488,"toc":681},[489,520,524,532,536,598,602,638,642,649,651],[55,490,57,491,494,495,499,500,503,504,503,508,503,511,99,515,519],{},[59,492,493],{},"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 ",[64,496,498],{"href":497},"\u002Fglossary\u002Facoustic-cleaner","acoustic cleaner"," and the default specification for cleaning ",[64,501,502],{"href":273},"ESPs",", ",[64,505,507],{"href":506},"\u002Fglossary\u002Ffabric-filter","baghouses",[64,509,510],{"href":293},"SCR catalysts",[64,512,514],{"href":513},"\u002Fglossary\u002Fsuperheater","boiler heat-transfer surfaces",[64,516,518],{"href":517},"\u002Fglossary\u002Fhopper","hoppers and silos",".",[75,521,523],{"id":522},"how-a-sonic-horn-works","How a sonic horn works",[55,525,526,527,531],{},"Compressed plant air admitted through a ",[64,528,530],{"href":529},"\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.",[75,533,535],{"id":534},"key-parameters","Key parameters",[217,537,538,548],{},[220,539,540],{},[223,541,542,545],{},[226,543,544],{},"Parameter",[226,546,547],{},"Typical range",[233,549,550,558,566,574,582,590],{},[223,551,552,555],{},[238,553,554],{},"Fundamental frequency",[238,556,557],{},"60–400 Hz",[223,559,560,563],{},[238,561,562],{},"Sound pressure level",[238,564,565],{},"140–180 dB",[223,567,568,571],{},[238,569,570],{},"Compressed-air consumption",[238,572,573],{},"8–14 Nm³\u002Fmin at 4–7 bar",[223,575,576,579],{},[238,577,578],{},"Operating temperature (with appropriate materials)",[238,580,581],{},"−40 °C to +500 °C",[223,583,584,587],{},[238,585,586],{},"Firing cycle",[238,588,589],{},"5–15 s burst, repeated every 3–15 minutes",[223,591,592,595],{},[238,593,594],{},"Mass",[238,596,597],{},"15–60 kg depending on horn size",[75,599,601],{"id":600},"frequency-selection","Frequency selection",[55,603,604,605,503,609,612,613,503,617,621,622,503,625,629,630,99,634,519],{},"Lower frequencies (60–125 Hz) project longer wavelengths and penetrate further into large open vessels — ",[64,606,608],{"href":607},"\u002Fglossary\u002Fpreheater-cyclone","preheater cyclones",[64,610,611],{"href":90},"recovery-boiler superheaters",", large ",[64,614,616],{"href":615},"\u002Fglossary\u002Fesp-field-bus-section","ESP fields",[64,618,620],{"href":619},"\u002Fglossary\u002Fsilo","silos",". Higher frequencies (230–400 Hz) carry more energy per unit volume and suit finer dust loads in ",[64,623,624],{"href":506},"fabric-filter compartments",[64,626,628],{"href":627},"\u002Fglossary\u002Fhoneycomb-catalyst","catalyst layers"," and smaller hopper geometries. See ",[64,631,633],{"href":632},"\u002Fglossary\u002Flow-frequency-acoustic-cleaner","low-frequency acoustic cleaner",[64,635,637],{"href":636},"\u002Fglossary\u002Fhigh-frequency-acoustic-cleaner","high-frequency acoustic cleaner",[75,639,641],{"id":640},"sonic-horn-vs-steam-sootblower","Sonic horn vs steam sootblower",[55,643,644,645,648],{},"Sonic horns are increasingly specified alongside or in place of ",[64,646,647],{"href":126},"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.",[75,650,144],{"id":143},[80,652,653,658,664,670,676],{},[83,654,655],{},[64,656,657],{"href":497},"Acoustic cleaner",[83,659,660],{},[64,661,663],{"href":662},"\u002Fglossary\u002Fsonic-sootblower","Sonic sootblower",[83,665,666],{},[64,667,669],{"href":668},"\u002Fglossary\u002Fbell-horn","Bell horn",[83,671,672],{},[64,673,675],{"href":674},"\u002Fglossary\u002Fdiaphragm-horn","Diaphragm horn",[83,677,678],{},[64,679,680],{"href":632},"Low-frequency acoustic cleaner",{"title":163,"searchDepth":164,"depth":164,"links":682},[683,684,685,686,687],{"id":522,"depth":164,"text":523},{"id":534,"depth":164,"text":535},{"id":600,"depth":164,"text":601},{"id":640,"depth":164,"text":641},{"id":143,"depth":164,"text":144},"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.",{},[692,693,694,695,696,697],"acoustic-cleaner","acoustic-cleaning-system","sonic-sootblower","bell-horn","diaphragm-horn","low-frequency-acoustic-cleaner",{"title":699,"description":700},"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.",[702,705,708],{"title":703,"url":704},"Power Engineering — Sonic Horns: A User's Introduction","https:\u002F\u002Fwww.power-eng.com\u002Fcoal\u002Fsonic-horns-a-userrsquos-introduction\u002F",{"title":706,"url":707},"Power Engineering — Tuning in to Acoustic Cleaning","https:\u002F\u002Fwww.power-eng.com\u002Fcoal\u002Ftuning-in-to-acoustic-cleaning\u002F",{"title":709,"url":710},"Wikipedia — Sonic soot blowers","https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FSonic_soot_blowers","glossary\u002Fsonic-horn","YzrhN0kKzqSaQo0wfn0rueNZ-V43mcg5zahqeWi3lnU",1782613727215]