[{"data":1,"prerenderedAt":441},["ShallowReactive",2],{"site-footer-common":3,"glossary:duct-burner":45,"glossary-related:duct-burner":155},{"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":136,"description":137,"extension":138,"meta":139,"navigation":140,"path":141,"relatedTerms":142,"seo":146,"sources":149,"stem":153,"term":47,"__hash__":154},"glossary\u002Fglossary\u002Fduct-burner.md","Duct burner",[49,50],"HRSG duct burner","supplementary firing",{"type":52,"value":53,"toc":129},"minimark",[54,69,82,87,95,99,107,111],[55,56,57,58,62,63,68],"p",{},"A ",[59,60,61],"strong",{},"duct burner"," is an auxiliary natural-gas or distillate-oil burner installed in the inlet duct of an ",[64,65,67],"a",{"href":66},"\u002Fglossary\u002Fheat-recovery-steam-generator","HRSG"," to add heat to the gas-turbine exhaust before it enters the first tube bank. Duct burners are used for:",[70,71,72,76,79],"ul",{},[73,74,75],"li",{},"Steam-flow boosting beyond the gas-turbine-only HRSG capacity",[73,77,78],{},"Cogeneration peak shaping where process steam demand exceeds nominal HRSG output",[73,80,81],{},"Cold-start steam-temperature ramp control",[83,84,86],"h2",{"id":85},"effect-on-fouling","Effect on fouling",[55,88,89,90,94],{},"Duct-burner firing raises the temperature and changes the gas composition entering the ",[64,91,93],{"href":92},"\u002Fglossary\u002Ffinned-tube-harp-tube","finned-tube"," banks. On natural-gas-only HRSGs, this adds little fouling; on duct burners firing oil or in any unit firing back-up fuel, particulate loading rises substantially and convective-pass fouling accelerates.",[83,96,98],{"id":97},"cleaning-implications","Cleaning implications",[55,100,101,102,106],{},"HRSGs that operate with regular duct-burner firing on liquid fuels usually need more aggressive ",[64,103,105],{"href":104},"\u002Fglossary\u002Fsonic-horn","sonic-horn"," coverage on the HRSG harps than gas-only HRSGs do.",[83,108,110],{"id":109},"related-terms","Related terms",[70,112,113,118,124],{},[73,114,115],{},[64,116,117],{"href":66},"Heat Recovery Steam Generator (HRSG)",[73,119,120],{},[64,121,123],{"href":122},"\u002Fglossary\u002Fcombined-cycle-gas-turbine","Combined-cycle gas turbine (CCGT)",[73,125,126],{},[64,127,128],{"href":92},"Finned tube \u002F harp tube",{"title":130,"searchDepth":131,"depth":131,"links":132},"",2,[133,134,135],{"id":85,"depth":131,"text":86},{"id":97,"depth":131,"text":98},{"id":109,"depth":131,"text":110},"hrsg-gas-path","A duct burner is an auxiliary natural-gas or distillate-oil burner installed in the inlet duct of an HRSG to add heat to the gas-turbine exhaust before it enters the first tube bank. Duct burners are used for:","md",{},true,"\u002Fglossary\u002Fduct-burner",[143,144,145],"heat-recovery-steam-generator","combined-cycle-gas-turbine","finned-tube-harp-tube",{"title":147,"description":148},"Duct burner — supplementary firing in the HRSG gas path","A duct burner is an auxiliary gas burner installed in the HRSG inlet duct to add heat to the gas-turbine exhaust. Used for steam-flow boosting and cogeneration peak shaping.",[150],{"title":151,"url":152},"Wikipedia — Heat recovery steam generator","https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FHeat_recovery_steam_generator","glossary\u002Fduct-burner","sPgINXKI3DVBZ9j_4oCwpk-x5CSkcumgPsjS_2-O9JA",[156,275,355],{"id":157,"title":117,"aliases":158,"body":160,"category":136,"description":259,"extension":138,"meta":260,"navigation":140,"path":66,"relatedTerms":261,"seo":264,"sources":267,"stem":272,"term":273,"__hash__":274},"glossary\u002Fglossary\u002Fheat-recovery-steam-generator.md",[67,159],"heat-recovery steam generator",{"type":52,"value":161,"toc":253},[162,171,175,181,185,188,217,221,227,229],[55,163,57,164,166,167,170],{},[59,165,117],{}," recovers heat from the exhaust of a gas turbine to generate steam — the second cycle of a ",[64,168,169],{"href":122},"combined-cycle gas turbine (CCGT)"," power plant. HRSGs raise overall plant efficiency from the ~38% of a simple-cycle gas turbine to 55–62% of a modern combined-cycle plant.",[83,172,174],{"id":173},"hrsg-layout","HRSG layout",[55,176,177,178,180],{},"A typical HRSG contains multiple ",[64,179,93],{"href":92}," tube banks arranged in series along the gas-path direction: superheaters, evaporators, economisers, and (on units with SCR) the catalyst layers. Modern HRSGs operate at three pressure levels (HP, IP, LP) to maximise energy recovery from the cooling exhaust gas.",[83,182,184],{"id":183},"fouling","Fouling",[55,186,187],{},"HRSG fouling is generally lighter than coal-fired boiler fouling because gas-turbine exhaust contains far less particulate. The dominant fouling mechanisms are:",[70,189,190,199,205,211],{},[73,191,192,198],{},[59,193,194],{},[64,195,197],{"href":196},"\u002Fglossary\u002Fammonium-bisulphate","Ammonium bisulphate (ABS)"," on units with SCR — slipped ammonia + SO₃ from fuel sulphur condenses on finned tubes",[73,200,201,204],{},[59,202,203],{},"Fine ash deposition"," on finned-tube banks reducing heat transfer",[73,206,207,210],{},[59,208,209],{},"Duct-burner-driven"," particulate on units with supplementary firing",[73,212,213,216],{},[59,214,215],{},"Cold-end corrosion"," below the acid dew point on sulphur-bearing fuels",[83,218,220],{"id":219},"cleaning","Cleaning",[55,222,223,226],{},[64,224,225],{"href":104},"Sonic horns"," installed across the gas path are increasingly common on HRSG maintenance plans, particularly for keeping SCR catalyst layers and cold-end finned tubes clear of ABS without the need for offline water-wash campaigns.",[83,228,110],{"id":109},[70,230,231,235,239,243,248],{},[73,232,233],{},[64,234,123],{"href":122},[73,236,237],{},[64,238,128],{"href":92},[73,240,241],{},[64,242,47],{"href":141},[73,244,245],{},[64,246,247],{"href":196},"Ammonium bisulphate",[73,249,250],{},[64,251,252],{"href":104},"Sonic horn",{"title":130,"searchDepth":131,"depth":131,"links":254},[255,256,257,258],{"id":173,"depth":131,"text":174},{"id":183,"depth":131,"text":184},{"id":219,"depth":131,"text":220},{"id":109,"depth":131,"text":110},"A Heat Recovery Steam Generator (HRSG) recovers heat from the exhaust of a gas turbine to generate steam — the second cycle of a combined-cycle gas turbine (CCGT) power plant. HRSGs raise overall plant efficiency from the ~38% of a simple-cycle gas turbine to 55–62% of a modern combined-cycle plant.",{},[144,145,262,263,105],"duct-burner","ammonium-bisulphate",{"title":265,"description":266},"Heat Recovery Steam Generator (HRSG) — convert gas-turbine exhaust to steam","An HRSG recovers heat from a gas turbine's exhaust to generate steam, the second cycle of a combined-cycle plant. Finned-tube ash deposition and ABS fouling are the main cleaning concerns.",[268,269],{"title":151,"url":152},{"title":270,"url":271},"Combined Cycle Journal — Clean HRSG heat-transfer surfaces","https:\u002F\u002Fwww.ccj-online.com\u002Fclean-heat-transfer-surfaces-inside-and-out-to-keep-hrsgs-at-peak-efficiency\u002F","glossary\u002Fheat-recovery-steam-generator","Heat Recovery Steam Generator","2QpNZZDCPIfd-x3tx7w8wKqru7_s0rVDnW6E_FXNJVw",{"id":276,"title":123,"aliases":277,"body":281,"category":136,"description":340,"extension":138,"meta":341,"navigation":140,"path":122,"relatedTerms":342,"seo":345,"sources":348,"stem":352,"term":353,"__hash__":354},"glossary\u002Fglossary\u002Fcombined-cycle-gas-turbine.md",[278,279,280],"CCGT","combined cycle","combined-cycle plant",{"type":52,"value":282,"toc":335},[283,291,295,304,308,311,313],[55,284,57,285,287,288,290],{},[59,286,169],{}," plant combines a gas turbine with a steam turbine driven by an ",[64,289,67],{"href":66}," that recovers heat from the gas-turbine exhaust. The arrangement raises overall plant efficiency from ~38% LHV for a simple-cycle gas turbine to 55–62% LHV for modern CCGT, with the latest H-class machines pushing 64%+.",[83,292,294],{"id":293},"why-hrsg-cleanliness-matters","Why HRSG cleanliness matters",[55,296,297,298,300,301,303],{},"CCGT plants are economically dispatched ahead of coal in most markets, but margins per MWh are tight and competition from renewables intensifies the focus on heat rate. Every 0.5% efficiency loss from HRSG fouling translates directly to fuel cost. ",[64,299,225],{"href":104}," on the ",[64,302,67],{"href":66}," gas path are increasingly part of the standard maintenance toolkit on modern combined-cycle plants.",[83,305,307],{"id":306},"cycling-adds-complication","Cycling adds complication",[55,309,310],{},"Modern CCGT plants increasingly two-shift — running daytime and shutting overnight when renewable supply meets demand. Frequent start-stop cycling worsens HRSG fouling because cold metal surfaces during shutdowns condense moisture that bonds dust into a harder deposit. Continuous sonic-horn cleaning helps offset cycling-driven fouling acceleration.",[83,312,110],{"id":109},[70,314,315,319,323,329],{},[73,316,317],{},[64,318,117],{"href":66},[73,320,321],{},[64,322,47],{"href":141},[73,324,325],{},[64,326,328],{"href":327},"\u002Fglossary\u002Fselective-catalytic-reduction","Selective Catalytic Reduction (SCR)",[73,330,331],{},[64,332,334],{"href":333},"\u002Fglossary\u002Fheat-rate","Heat rate",{"title":130,"searchDepth":131,"depth":131,"links":336},[337,338,339],{"id":293,"depth":131,"text":294},{"id":306,"depth":131,"text":307},{"id":109,"depth":131,"text":110},"A combined-cycle gas turbine (CCGT) plant combines a gas turbine with a steam turbine driven by an HRSG that recovers heat from the gas-turbine exhaust. The arrangement raises overall plant efficiency from ~38% LHV for a simple-cycle gas turbine to 55–62% LHV for modern CCGT, with the latest H-class machines pushing 64%+.",{},[143,262,343,344],"selective-catalytic-reduction","heat-rate",{"title":346,"description":347},"Combined-cycle gas turbine (CCGT) — gas turbine plus HRSG and steam turbine","A CCGT plant combines a gas turbine with a steam turbine driven by an HRSG recovering exhaust heat. Plant efficiency reaches 55–62% LHV; HRSG cleanliness is critical.",[349],{"title":350,"url":351},"Wikipedia — Combined cycle power plant","https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FCombined_cycle_power_plant","glossary\u002Fcombined-cycle-gas-turbine","Combined-cycle gas turbine","by8SpjeEI8ON6lFVMPJSYZgoB4OvOKZUqmCtbhUvCds",{"id":356,"title":128,"aliases":357,"body":362,"category":136,"description":430,"extension":138,"meta":431,"navigation":140,"path":92,"relatedTerms":432,"seo":433,"sources":436,"stem":438,"term":439,"__hash__":440},"glossary\u002Fglossary\u002Ffinned-tube-harp-tube.md",[358,359,360,361],"finned tubes","harp tube","extended-surface tube","HRSG harp",{"type":52,"value":363,"toc":425},[364,374,389,393,396,398,403,405],[55,365,57,366,369,370,373],{},[59,367,368],{},"finned tube"," carries helically-wound (or stud-welded) metal fins on its outside surface, multiplying the gas-side heat-transfer area by 5–10× compared with a bare tube. Finned tubes are universal in ",[64,371,372],{"href":66},"HRSGs"," because gas-side heat transfer (low-pressure exhaust gas) is the limiting factor — adding fins is the standard way to compensate.",[55,375,57,376,378,379,383,384,388],{},[59,377,359],{}," is the assembled vertical bundle of finned tubes that forms one tube bank inside the HRSG, named for its resemblance to a harp string array. Multiple harps in series make up the ",[64,380,382],{"href":381},"\u002Fglossary\u002Feconomiser","economiser",", evaporator and ",[64,385,387],{"href":386},"\u002Fglossary\u002Fsuperheater","superheater"," sections.",[83,390,392],{"id":391},"why-finned-surfaces-foul-easily","Why finned surfaces foul easily",[55,394,395],{},"The narrow gap between fins (3–10 mm typical pitch) is geometrically sensitive: even a thin deposit on the fin face significantly restricts the gas flow path between fins. Particulate that would pass through a bare-tube bank settles between fins and consolidates over time.",[83,397,220],{"id":219},[55,399,400,402],{},[64,401,225],{"href":104}," installed across HRSG harps keep the fin gaps clear. Sound waves penetrate between fins more effectively than steam-jet sootblowers, which struggle to project energy into the narrow inter-fin space. Combined sonic-and-sootblower cleaning regimes maintain HRSG heat transfer through the operating campaign.",[83,404,110],{"id":109},[70,406,407,411,416,421],{},[73,408,409],{},[64,410,117],{"href":66},[73,412,413],{},[64,414,415],{"href":381},"Economiser",[73,417,418],{},[64,419,420],{"href":386},"Superheater",[73,422,423],{},[64,424,252],{"href":104},{"title":130,"searchDepth":131,"depth":131,"links":426},[427,428,429],{"id":391,"depth":131,"text":392},{"id":219,"depth":131,"text":220},{"id":109,"depth":131,"text":110},"A finned tube carries helically-wound (or stud-welded) metal fins on its outside surface, multiplying the gas-side heat-transfer area by 5–10× compared with a bare tube. Finned tubes are universal in HRSGs because gas-side heat transfer (low-pressure exhaust gas) is the limiting factor — adding fins is the standard way to compensate.",{},[143,382,387,105],{"title":434,"description":435},"Finned tube and harp tube — extended-surface tubes for HRSG heat transfer","Finned tubes carry helically-wound fins to multiply gas-side surface area in HRSGs. Harp tubes are the vertical bundle configuration. Fin geometry is particularly fouling-sensitive.",[437],{"title":151,"url":152},"glossary\u002Ffinned-tube-harp-tube","Finned tube and harp tube","FPHrkmT6ywb1eMnRbmeu0wDTvbn2kby9DVOqaObqYZU",1782613742679]