[{"data":1,"prerenderedAt":838},["ShallowReactive",2],{"site-footer-common":3,"glossary:rotary-kiln":45,"glossary-related:rotary-kiln":213},{"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":193,"description":194,"extension":195,"meta":196,"navigation":197,"path":198,"relatedTerms":199,"seo":204,"sources":207,"stem":211,"term":47,"__hash__":212},"glossary\u002Fglossary\u002Frotary-kiln.md","Rotary kiln",[49,50],"cement kiln","rotary cement kiln",{"type":52,"value":53,"toc":185},"minimark",[54,69,74,92,96,99,103,106,145,152,156],[55,56,57,58,62,63,68],"p",{},"A ",[59,60,61],"strong",{},"rotary kiln"," is a long (typically 50–100 m), large-diameter (typically 4–6 m), gently inclined rotating steel cylinder lined with refractory brick where preheated raw meal is burned at flame temperatures of ~2,000 °C and material temperatures of ~1,450 °C to form ",[64,65,67],"a",{"href":66},"\u002Fglossary\u002Fclinker","clinker",". The rotary kiln is the heart of every cement plant.",[70,71,73],"h2",{"id":72},"layout","Layout",[55,75,76,77,81,82,86,87,91],{},"The kiln is fed at its upper end by raw meal pre-calcined in the ",[64,78,80],{"href":79},"\u002Fglossary\u002Fpreheater-tower","preheater tower"," and ",[64,83,85],{"href":84},"\u002Fglossary\u002Fcalciner","calciner",". The main burner fires at the lower (clinker discharge) end, opposing the gas flow direction. Discharged clinker falls into the ",[64,88,90],{"href":89},"\u002Fglossary\u002Fclinker-cooler","clinker cooler"," below.",[70,93,95],{"id":94},"why-kiln-stops-are-catastrophic","Why kiln stops are catastrophic",[55,97,98],{},"A cement kiln is designed for continuous operation. Stopping and restarting the kiln means cooling and re-heating massive refractory mass, which damages the lining and incurs substantial fuel cost. A typical unplanned kiln stop loses 24–72 hours of clinker production, equivalent to thousands of tonnes of lost output.",[70,100,102],{"id":101},"what-stops-the-kiln","What stops the kiln",[55,104,105],{},"Most unplanned kiln stops trace to upstream or downstream problems rather than the kiln itself:",[107,108,109,118,127,133,139],"ul",{},[110,111,112,115,116],"li",{},[59,113,114],{},"Preheater pluggage"," — see ",[64,117,80],{"href":79},[110,119,120,126],{},[59,121,122],{},[64,123,125],{"href":124},"\u002Fglossary\u002Fkiln-inlet-ring-snowman","Kiln-inlet ring \u002F snowman"," formation",[110,128,129,132],{},[59,130,131],{},"Clinker cooler upset"," — bridging in the cooler hopper",[110,134,135,138],{},[59,136,137],{},"Calciner pluggage"," — accreted build-up from AFR firing",[110,140,141,144],{},[59,142,143],{},"ID-fan trip"," — fouled blades causing vibration",[55,146,147,151],{},[64,148,150],{"href":149},"\u002Fglossary\u002Fsonic-horn","Sonic horns"," installed across the preheater, calciner and kiln-inlet area address several of these directly.",[70,153,155],{"id":154},"related-terms","Related terms",[107,157,158,163,168,174,179],{},[110,159,160],{},[64,161,162],{"href":66},"Clinker",[110,164,165],{},[64,166,167],{"href":89},"Clinker cooler",[110,169,170],{},[64,171,173],{"href":172},"\u002Fglossary\u002Fkiln-inlet-riser-duct","Kiln inlet \u002F riser duct",[110,175,176],{},[64,177,178],{"href":79},"Preheater tower",[110,180,181],{},[64,182,184],{"href":183},"\u002Fglossary\u002Falternative-fuel","Alternative fuel",{"title":186,"searchDepth":187,"depth":187,"links":188},"",2,[189,190,191,192],{"id":72,"depth":187,"text":73},{"id":94,"depth":187,"text":95},{"id":101,"depth":187,"text":102},{"id":154,"depth":187,"text":155},"cement","A rotary kiln is a long (typically 50–100 m), large-diameter (typically 4–6 m), gently inclined rotating steel cylinder lined with refractory brick where preheated raw meal is burned at flame temperatures of ~2,000 °C and material temperatures of ~1,450 °C to form clinker. The rotary kiln is the heart of every cement plant.","md",{},true,"\u002Fglossary\u002Frotary-kiln",[67,200,201,202,203],"clinker-cooler","kiln-inlet-riser-duct","preheater-tower","alternative-fuel",{"title":205,"description":206},"Rotary kiln — the heart of the cement plant","A rotary kiln is a long inclined rotating cylinder where preheated raw meal is burned at 1,450 °C to form clinker. The heart of every cement plant.",[208],{"title":209,"url":210},"Wikipedia — Cement kiln","https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FCement_kiln","glossary\u002Frotary-kiln","MIYT9G3DCofPYVl4SqD8erG8mcl6gg4VWmUXfvLV0fc",[214,288,395,513,655],{"id":215,"title":162,"aliases":216,"body":219,"category":193,"description":274,"extension":195,"meta":275,"navigation":197,"path":66,"relatedTerms":276,"seo":279,"sources":282,"stem":286,"term":162,"__hash__":287},"glossary\u002Fglossary\u002Fclinker.md",[217,218],"cement clinker","clinker nodules",{"type":52,"value":220,"toc":270},[221,232,236,239,252,254],[55,222,223,225,226,228,229,231],{},[59,224,162],{}," is the dark, hard nodular intermediate product of cement manufacture. Raw meal — a mixture of limestone, clay, sand and iron — is burned at material temperatures of ~1,450 °C in the ",[64,227,61],{"href":198}," to drive the sequence of reactions that form the calcium-silicate minerals (alite, belite) that give cement its hydraulic properties. The resulting nodules — typically 3–25 mm in size — are then cooled in the ",[64,230,90],{"href":89}," and ground with gypsum to produce finished cement powder.",[70,233,235],{"id":234},"why-clinker-matters-operationally","Why clinker matters operationally",[55,237,238],{},"Clinker is the value-bearing intermediate in cement manufacture. Lost clinker production from an unplanned kiln stop directly maps to lost revenue: a 5,000 t\u002Fday kiln stopped for 24 hours destroys ~5,000 t of clinker output, equivalent to ~$300,000 in selling-price-equivalent product.",[55,240,241,242,245,246,81,248,251],{},"Every operational improvement that protects kiln availability — including ",[64,243,244],{"href":149},"sonic-horn"," installation on the ",[64,247,80],{"href":79},[64,249,250],{"href":172},"kiln inlet"," — defends clinker output. This is the underlying economic logic for acoustic cleaning in the cement industry.",[70,253,155],{"id":154},[107,255,256,260,264],{},[110,257,258],{},[64,259,47],{"href":198},[110,261,262],{},[64,263,167],{"href":89},[110,265,266],{},[64,267,269],{"href":268},"\u002Fglossary\u002Fraw-mill-cement-mill-coal-mill","Raw mill \u002F cement mill \u002F coal mill",{"title":186,"searchDepth":187,"depth":187,"links":271},[272,273],{"id":234,"depth":187,"text":235},{"id":154,"depth":187,"text":155},"Clinker is the dark, hard nodular intermediate product of cement manufacture. Raw meal — a mixture of limestone, clay, sand and iron — is burned at material temperatures of ~1,450 °C in the rotary kiln to drive the sequence of reactions that form the calcium-silicate minerals (alite, belite) that give cement its hydraulic properties. The resulting nodules — typically 3–25 mm in size — are then cooled in the clinker cooler and ground with gypsum to produce finished cement powder.",{},[277,200,278],"rotary-kiln","raw-mill-cement-mill-coal-mill",{"title":280,"description":281},"Clinker — the intermediate product of cement manufacture","Clinker is the dark, hard nodular intermediate product of cement manufacture, formed by burning raw meal at 1,450 °C in the rotary kiln before grinding to cement powder.",[283],{"title":284,"url":285},"Wikipedia — Cement clinker","https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FCement_clinker","glossary\u002Fclinker","vLdWVe6SN8tpgSfToU5mXX1uao0_LXdP9UfQi_knTLg",{"id":289,"title":167,"aliases":290,"body":293,"category":193,"description":384,"extension":195,"meta":385,"navigation":197,"path":89,"relatedTerms":386,"seo":388,"sources":391,"stem":393,"term":167,"__hash__":394},"glossary\u002Fglossary\u002Fclinker-cooler.md",[291,292],"grate cooler","cement cooler",{"type":52,"value":294,"toc":379},[295,317,321,328,348,352,357,359],[55,296,57,297,299,300,302,303,305,306,308,309,311,312,316],{},[59,298,90],{}," (most commonly a ",[59,301,291],{},") quenches hot ",[64,304,67],{"href":66}," discharged from the ",[64,307,61],{"href":198}," at ~1,400 °C down to ~100 °C using forced ambient air blown upward through a perforated grate. Hot air recovered from the cooler is used as secondary combustion air at the main kiln burner and as tertiary air at the ",[64,310,85],{"href":84}," via the ",[64,313,315],{"href":314},"\u002Fglossary\u002Ftertiary-air-duct","tertiary air duct (TAD)",".",[70,318,320],{"id":319},"cooler-related-fouling","Cooler-related fouling",[55,322,323,324,327],{},"The cooler itself rarely fouls but generates substantial fines that drop out into hoppers below and along the ",[64,325,326],{"href":314},"TAD",":",[107,329,330,336,342],{},[110,331,332,335],{},[59,333,334],{},"Cooler dust hopper bridging"," — hopper outlets clog with fine clinker dust",[110,337,338,341],{},[59,339,340],{},"Pulse-jet filter pluggage"," on cooler vent baghouses",[110,343,344,347],{},[59,345,346],{},"TAD bottom dropout"," along the air route to the calciner",[70,349,351],{"id":350},"sonic-horn-duty","Sonic-horn duty",[55,353,354,356],{},[64,355,150],{"href":149}," installed on the cooler dust hoppers prevent bridging and maintain dust extraction. The horns must tolerate the high-temperature environment immediately below the kiln-discharge zone; stainless-steel construction is standard.",[70,358,155],{"id":154},[107,360,361,365,369,374],{},[110,362,363],{},[64,364,162],{"href":66},[110,366,367],{},[64,368,47],{"href":198},[110,370,371],{},[64,372,373],{"href":314},"Tertiary air duct (TAD)",[110,375,376],{},[64,377,378],{"href":149},"Sonic horn",{"title":186,"searchDepth":187,"depth":187,"links":380},[381,382,383],{"id":319,"depth":187,"text":320},{"id":350,"depth":187,"text":351},{"id":154,"depth":187,"text":155},"A clinker cooler (most commonly a grate cooler) quenches hot clinker discharged from the rotary kiln at ~1,400 °C down to ~100 °C using forced ambient air blown upward through a perforated grate. Hot air recovered from the cooler is used as secondary combustion air at the main kiln burner and as tertiary air at the calciner via the tertiary air duct (TAD).",{},[67,277,387,244],"tertiary-air-duct",{"title":389,"description":390},"Clinker cooler — quench cooler at the rotary kiln discharge","A clinker cooler quenches hot clinker discharged from the rotary kiln using forced ambient air. Hot air recovered is sent to the calciner via the TAD; cooler dust hoppers benefit from sonic horns.",[392],{"title":209,"url":210},"glossary\u002Fclinker-cooler","QXNM4UlwGH82bX8us1X5_raAfNpFEkzmyhE_Rx9WnQs",{"id":396,"title":173,"aliases":397,"body":400,"category":193,"description":501,"extension":195,"meta":502,"navigation":197,"path":172,"relatedTerms":503,"seo":505,"sources":508,"stem":510,"term":511,"__hash__":512},"glossary\u002Fglossary\u002Fkiln-inlet-riser-duct.md",[250,398,399],"riser duct","kiln riser",{"type":52,"value":401,"toc":496},[402,418,422,441,448,452,471,473],[55,403,404,405,408,409,411,412,414,415,417],{},"The ",[59,406,407],{},"kiln inlet \u002F riser duct"," is the connection between the upper end of the ",[64,410,61],{"href":198}," and the ",[64,413,85],{"href":84}," \u002F ",[64,416,80],{"href":79}," above. Hot kiln gas rises through the inlet into the calciner, and pre-calcined meal descends from the calciner into the kiln. The geometry — narrow, hot, dust-laden — makes this the single most fouled location in any cement plant.",[70,419,421],{"id":420},"why-it-fouls-so-heavily","Why it fouls so heavily",[107,423,424,427,430,433,438],{},[110,425,426],{},"Temperature is in the alkali \u002F chloride condensation window (~800 °C at the inlet)",[110,428,429],{},"Gas-side velocity is high",[110,431,432],{},"Sticky pre-calcined meal contacts cooler steel and refractory",[110,434,435,437],{},[64,436,184],{"href":183}," firing in the calciner adds chlorine and sulphur to the gas",[110,439,440],{},"The bend geometry creates dead zones where build-up accelerates",[55,442,443,444,447],{},"The visible result is the ",[64,445,446],{"href":124},"kiln-inlet ring or \"snowman\""," — a massive accretion that can completely block the gas path if untreated.",[70,449,451],{"id":450},"cleaning-intensity","Cleaning intensity",[55,453,454,455,461,462,466,467,316],{},"Cement plants typically run ",[59,456,457,458],{},"multiple ",[64,459,460],{"href":149},"sonic horns"," concentrated on the kiln inlet, supplemented by ",[64,463,465],{"href":464},"\u002Fglossary\u002Fair-cannon-air-blaster","air cannons"," for periodic remediation and manual water-lancing during planned outages. The mix and intensity scale up sharply on plants running > 50% ",[64,468,470],{"href":469},"\u002Fglossary\u002Fthermal-substitution-rate","TSR",[70,472,155],{"id":154},[107,474,475,479,483,487,492],{},[110,476,477],{},[64,478,47],{"href":198},[110,480,481],{},[64,482,178],{"href":79},[110,484,485],{},[64,486,125],{"href":124},[110,488,489],{},[64,490,491],{"href":84},"Calciner",[110,493,494],{},[64,495,378],{"href":149},{"title":186,"searchDepth":187,"depth":187,"links":497},[498,499,500],{"id":420,"depth":187,"text":421},{"id":450,"depth":187,"text":451},{"id":154,"depth":187,"text":155},"The kiln inlet \u002F riser duct is the connection between the upper end of the rotary kiln and the calciner \u002F preheater tower above. Hot kiln gas rises through the inlet into the calciner, and pre-calcined meal descends from the calciner into the kiln. The geometry — narrow, hot, dust-laden — makes this the single most fouled location in any cement plant.",{},[277,202,504,85,244],"kiln-inlet-ring-snowman",{"title":506,"description":507},"Kiln inlet and riser duct — the most-fouled point in any cement plant","The kiln inlet \u002F riser duct is the connection between the rotary kiln and the calciner \u002F preheater. It is the most-fouled location in any cement plant, the focal point for sonic-horn cleaning.",[509],{"title":209,"url":210},"glossary\u002Fkiln-inlet-riser-duct","Kiln inlet and riser duct","mSo67H5oiYYmuvreXfG8RTQB2lyD_SYb0CEy4PCxPPk",{"id":514,"title":178,"aliases":515,"body":519,"category":193,"description":640,"extension":195,"meta":641,"navigation":197,"path":79,"relatedTerms":642,"seo":645,"sources":648,"stem":653,"term":178,"__hash__":654},"glossary\u002Fglossary\u002Fpreheater-tower.md",[516,517,518],"cement preheater","preheater tower cement","cyclone preheater",{"type":52,"value":520,"toc":635},[521,534,538,549,565,569,572,602,605,607],[55,522,57,523,525,526,530,531,533],{},[59,524,80],{}," is a vertical stack of ",[64,527,529],{"href":528},"\u002Fglossary\u002Fpreheater-cyclone","cyclone separators"," that pre-heats incoming raw meal with hot exhaust gas from the ",[64,532,61],{"href":198}," before the meal enters the kiln itself. Modern cement plants use 4-, 5- or 6-stage preheater towers, recovering enough heat from kiln exhaust to deliver raw meal to the kiln at 800–900 °C.",[70,535,537],{"id":536},"why-preheater-towers-are-fouling-prone","Why preheater towers are fouling-prone",[55,539,540,541,543,544,548],{},"The lower preheater stages — and especially the ",[64,542,407],{"href":172}," — sit in a temperature window (700–900 °C) where alkali sulphates and chlorides condense from the gas onto cooler refractory and steel surfaces. The resulting ",[64,545,547],{"href":546},"\u002Fglossary\u002Fbuild-up-coating-accretion","build-up \u002F coating \u002F accretion"," grows progressively, narrows the gas path, and eventually causes a kiln stop for manual cleaning.",[55,550,551,552,555,556,560,561,316],{},"The fouling intensifies when ",[64,553,554],{"href":183},"alternative fuels (AFR)"," — ",[64,557,559],{"href":558},"\u002Fglossary\u002Frdf-srf-tdf","RDF \u002F SRF \u002F TDF"," — replace conventional fossil fuels, because waste fuels release more chlorine and sulphur into the ",[64,562,564],{"href":563},"\u002Fglossary\u002Fsulphur-cycle-chloride-cycle-alkali-cycle","sulphur and chloride cycles",[70,566,568],{"id":567},"cleaning-the-preheater","Cleaning the preheater",[55,570,571],{},"Acoustic cleaning is the dominant preventive technology on modern cement preheater towers:",[107,573,574,582,590,596],{},[110,575,576,581],{},[59,577,578,580],{},[64,579,150],{"href":149}," at 75–125 Hz"," mounted on the lower-stage cyclones and the kiln-inlet area",[110,583,584,589],{},[59,585,586],{},[64,587,588],{"href":464},"Air cannons"," as periodic remediation for the heaviest deposits",[110,591,592,595],{},[59,593,594],{},"Manual water-lancing"," during planned outages",[110,597,598,601],{},[59,599,600],{},"Operator monitoring"," of cyclone ΔP and meal-flow indicators as early warning",[55,603,604],{},"The Sylio value proposition on cement preheaters is preserving kiln availability — every avoided unplanned stop is worth 24–72 hours of clinker production.",[70,606,155],{"id":154},[107,608,609,614,618,622,626,631],{},[110,610,611],{},[64,612,613],{"href":528},"Preheater cyclone",[110,615,616],{},[64,617,491],{"href":84},[110,619,620],{},[64,621,47],{"href":198},[110,623,624],{},[64,625,173],{"href":172},[110,627,628],{},[64,629,630],{"href":469},"Thermal substitution rate",[110,632,633],{},[64,634,378],{"href":149},{"title":186,"searchDepth":187,"depth":187,"links":636},[637,638,639],{"id":536,"depth":187,"text":537},{"id":567,"depth":187,"text":568},{"id":154,"depth":187,"text":155},"A preheater tower is a vertical stack of cyclone separators that pre-heats incoming raw meal with hot exhaust gas from the rotary kiln before the meal enters the kiln itself. Modern cement plants use 4-, 5- or 6-stage preheater towers, recovering enough heat from kiln exhaust to deliver raw meal to the kiln at 800–900 °C.",{},[643,85,277,201,644,244],"preheater-cyclone","thermal-substitution-rate",{"title":646,"description":647},"Preheater tower — multi-stage cyclone heat exchanger feeding the cement kiln","A preheater tower is a vertical stack of cyclone separators that pre-heats raw meal with kiln exhaust gas before it enters the rotary kiln. The most fouling-prone section of any cement plant.",[649,650],{"title":209,"url":210},{"title":651,"url":652},"ECRA — Sulphur and Chloride Cycles","https:\u002F\u002Fwww.ecra-online.org\u002Fnewsletters\u002Fsulphur-and-chloride-cycles-and-the-use-of-alternative-fuels-or-raw-materials","glossary\u002Fpreheater-tower","nTZjuMnzN9vAh_OaO2iJWciYrv1LpKAM_yqg0BNl5TM",{"id":656,"title":657,"aliases":658,"body":663,"category":193,"description":825,"extension":195,"meta":826,"navigation":197,"path":183,"relatedTerms":827,"seo":831,"sources":834,"stem":836,"term":184,"__hash__":837},"glossary\u002Fglossary\u002Falternative-fuel.md","Alternative fuel (AFR)",[659,660,661,662],"AFR","alternative fuels","secondary fuel","waste-derived fuel",{"type":52,"value":664,"toc":819},[665,680,684,719,723,748,752,755,785,792,794],[55,666,667,669,670,673,674,676,677,679],{},[59,668,657],{}," — sometimes ",[671,672,661],"em",{}," or ",[671,675,662],{}," — refers to non-fossil energy sources used to replace coal, petcoke and natural gas in cement-kiln combustion. The cement industry is the largest single user of AFR worldwide because the high temperatures and long residence times in a ",[64,678,61],{"href":198}," destroy organic contaminants, and the alkaline raw materials neutralise acidic combustion products.",[70,681,683],{"id":682},"common-afr-streams","Common AFR streams",[107,685,686,692,698,704,707,710,713,716],{},[110,687,688,691],{},[64,689,690],{"href":558},"RDF"," — refuse-derived fuel",[110,693,694,697],{},[64,695,696],{"href":558},"SRF"," — solid recovered fuel (higher-spec RDF)",[110,699,700,703],{},[64,701,702],{"href":558},"TDF"," — tyre-derived fuel",[110,705,706],{},"Sewage sludge (dried)",[110,708,709],{},"Animal-meal residues",[110,711,712],{},"Agricultural residues",[110,714,715],{},"Used solvents and waste oils",[110,717,718],{},"Plastic and paper fractions",[70,720,722],{"id":721},"drivers","Drivers",[107,724,725,731,737,743],{},[110,726,727,730],{},[59,728,729],{},"CO₂ reduction"," — biomass fractions reduce net carbon emissions",[110,732,733,736],{},[59,734,735],{},"Waste-disposal economics"," — gate fees offset fuel cost",[110,738,739,742],{},[59,740,741],{},"EU ETS pressure"," — carbon prices punish fossil-fuel firing",[110,744,745],{},[59,746,747],{},"Regional waste-management policies",[70,749,751],{"id":750},"operational-consequences","Operational consequences",[55,753,754],{},"AFR firing typically intensifies several existing operational problems:",[107,756,757,762,771,779],{},[110,758,759,760],{},"More chlorine and sulphur in the ",[64,761,564],{"href":563},[110,763,764,765,81,768],{},"More ",[64,766,767],{"href":124},"kiln-inlet build-up",[64,769,770],{"href":546},"preheater coatings",[110,772,773,774,778],{},"More frequent ",[64,775,777],{"href":776},"\u002Fglossary\u002Fchloride-bypass","chloride bypass"," operation",[110,780,781,782,784],{},"More demanding ",[64,783,85],{"href":84}," burner control",[55,786,787,81,789,791],{},[64,788,150],{"href":149},[64,790,465],{"href":464}," on the preheater and kiln inlet become more important as TSR rises.",[70,793,155],{"id":154},[107,795,796,800,805,809,814],{},[110,797,798],{},[64,799,559],{"href":558},[110,801,802],{},[64,803,804],{"href":469},"Thermal substitution rate (TSR)",[110,806,807],{},[64,808,491],{"href":84},[110,810,811],{},[64,812,813],{"href":776},"Chloride bypass",[110,815,816],{},[64,817,818],{"href":563},"Sulphur \u002F chloride \u002F alkali cycles",{"title":186,"searchDepth":187,"depth":187,"links":820},[821,822,823,824],{"id":682,"depth":187,"text":683},{"id":721,"depth":187,"text":722},{"id":750,"depth":187,"text":751},{"id":154,"depth":187,"text":155},"Alternative fuel (AFR) — sometimes secondary fuel or waste-derived fuel — refers to non-fossil energy sources used to replace coal, petcoke and natural gas in cement-kiln combustion. The cement industry is the largest single user of AFR worldwide because the high temperatures and long residence times in a rotary kiln destroy organic contaminants, and the alkaline raw materials neutralise acidic combustion products.",{},[828,644,85,829,830],"rdf-srf-tdf","chloride-bypass","sulphur-cycle-chloride-cycle-alkali-cycle",{"title":832,"description":833},"Alternative fuel (AFR) — non-fossil fuels for cement kilns","Alternative fuels (AFR) replace fossil fuel in cement kilns. They cut CO2 emissions and waste-disposal cost but increase chlorine, sulphur and alkali loading in the kiln gas.",[835],{"title":209,"url":210},"glossary\u002Falternative-fuel","8a9Wktj3h9L0w-C7tMXKI-y1T31K4IsFiIBPj8b461Y",1782613729017]