希臘火希臘火(flamethrower)+與石棉Asbestos3猛火油柜(flamethrower)

(c.a.1045AD)改變歷史的照片與改變歷史的發(fā)明HoytC.HottelPhanTh?KimPhúc潘金福改變歷史的橙劑（孟山都Mosanto）液體安全之提綱揮發(fā)(liquidfuelsafety)泄漏動力學(xué)(forensicscience)點火與蔓延(hazardcontrol)揚沸現(xiàn)象(boilover)液滴動力學(xué)（dropletdynamics）水滅火動力學(xué)(firepointtheory)7閃點什么是最低環(huán)境溫度，可以提供剛剛足夠的能量，讓液體表面的燃料濃度剛好可以達到支持閃燃的程度？由于液體表面的燃料濃度剛剛達到可燃限，所以點火過程會很快消耗那些位于可燃限附近的蒸汽，然后被高濃度的燃氣熄滅，這一短時間的一閃即滅的點燃過程，被稱作閃燃（flashfire）剛剛讓液體表面支持閃燃的環(huán)境溫度，稱作閃點（flashpoint）閃點是液體表面存在燃爆風(fēng)險的起點，因此對于液體燃料的存儲和運輸過程的風(fēng)險控制至關(guān)重要閃點必須用實驗方法來測定液體燃料的危險性隨溫度變化2025/6/269閃點的測量開杯與閉杯測量結(jié)果美國NFPA30液體安全性的分類FlammableIA–Flashpoint<73°F,boilingpoint<100°FFlammableIB–Flashpoint<73°F,boilingpoint>100°FFlammableIC–73°F<Flashpoint<100°FCombustibleII–100°F<Flashpoint<140°FCombustibleIIIA–140°F<Flashpoint<200°FCombustibleIIIB–Flashpoint>200°F在液體儲藏倉庫中的應(yīng)用燃料分類的地理要素由于地理位置的差異，英國采取不同的油品安全分類系統(tǒng).揮發(fā)公式的來源RudolphClausius德國物理學(xué)家和數(shù)學(xué)家熱力學(xué)科學(xué)最重要的貢獻者之一第一次引入了熵的概念顯著影響了氣體和電力動力學(xué)理論領(lǐng)域BenoitPaulémileClapeyron法國物理學(xué)家和工程師被認為是熱力學(xué)的創(chuàng)始人有助于研究完美的氣體和均質(zhì)固體的平衡Clausius-Clapeyron方程的多種形式Clausius-Clapeyron方程的微分形式Clausius-Clapeyron方程的積分形式Clausius-Clapeyron方程Additional/

complementaryequationsTrouton’sruleDalton’slawRaoult’slaw

HeatofvaporizationattemperatureTMolecularweightBoilingpoint液面上的蒸汽分布紅外相機注視下的揮發(fā)過程常規(guī)災(zāi)害計算程序1.計算表面濃度2.用Trouton’srule計算揮發(fā)的焓值3.用Raoult’slawandDalton’slaw計算蒸汽分壓力4.找到點火的環(huán)境溫度or蒸發(fā)率估算Quintiere,Fundamentalsoffirephenomena,Wiley&sons,2006,pp.148

20例題1:基于低燃限的

最小點火環(huán)境溫度（閃點）估算甲醇在標況（25Cand1atm）下的空氣中的最小點火溫度（閃點）:例題2：燃料的表面分布

學(xué)期結(jié)束，學(xué)生們希望喝點烈酒慶祝一下（ahottoddy）。他們有2inch高的烈酒杯，一半裝滿乙醇，放在微波爐內(nèi)。液體被加熱到50℃。假設(shè)蒸汽濃度在液體表面上方線性變化，乙醇的高低可燃限分別是3.3和19.0%（體積濃度）。計算酒杯中可以被點燃的區(qū)域。必要的數(shù)據(jù)，乙醇的汽化潛熱是840J/g，沸點是78C。hLhu例題03:從蒸氣壓到表面溫度SubstanceFormulaMWDhfkJmol-1

Dhc(lower)kJmol-1Dhc(lower)MJkg-1Cst(vol%)LFL(vol%)UFL(vol%)AIT(oC)inairFlashpoint(oC)Boilingpoint(oC)PvapatFP(atm)acetoneC3H6O58.08-249.41656.628.524.982.612.8465-18560.03622計算丙酮（acetone）的蒸氣壓達到0.036atm的環(huán)境溫度;;例題04:從表面濃度到表面溫度=>=>混合物的閃點液體燃料已知的一定是質(zhì)量濃度，首先需要轉(zhuǎn)換成摩爾濃度或體積濃度，這需要分子量和密度信息；在臨界溫度下，計算其飽和蒸氣壓；根據(jù)飽和蒸氣壓與摩爾濃度之乘積，就是蒸汽的分壓力；蒸汽分壓與環(huán)境壓力之比，就是蒸汽體積濃度；針對多種燃料，運用勒夏特列定理，可以得到表面濃度是否達到低燃限的結(jié)果。如果表面濃度可燃，說明液體閃點低于環(huán)境溫度，燃料屬于高風(fēng)險的易燃燃料，需要特殊的安全處理措施。混合物的安全性估算（1/2）混合物的安全性估算（2/2）燃料表面的蒸汽濃度（實驗結(jié)果）27總結(jié)閃點是定義液體燃料點火潛力的單一重要的參數(shù)。閃點對應(yīng)于液體表面濃度達到LFL的環(huán)境溫度。閃點依賴于揮發(fā)過程，后者是克勞修斯-克拉佩龍方程決定的結(jié)果。28美國航空燃料簡史萊特兄弟的發(fā)明為什么會成功？為什么他們的飛機會上天？通過活動環(huán)節(jié)的天才組合增加了飛機的可控性（他們是自行車生產(chǎn)商）新發(fā)明的內(nèi)燃機具有緊湊高效的特征。利用了下列成果EtinenneLenoir,1860年發(fā)明第一款內(nèi)燃機N.A.Otto,KarlBenz,1876年發(fā)明四沖程內(nèi)燃機SamuelLangley,1896年發(fā)明蒸汽機馬達CharlesManley,1901年發(fā)明內(nèi)燃機馬達TWA800爆炸事件讓美國重新回顧燃料的安全性汽油的妙用DistilledproductfromtheprocessofmakingKeroseneforillumination.(economyandavailability)Distillant(gasoline)isusedtobedampedintoseaforsafetyreasons.Duringthefirstworldwar,theengineknock(Pinking)becameaproblemToavoidthisproblem,engineersusefuelsoflightspecificgravity.(Evaporability)燃料研究ChemicalcompositionsoffuelshadaprofoundeffectuponengineperformanceAtasinglecompressionratio,differencesinpowerdevelopmentwereminorThemoredetonationresistantthefuel,thehigherthecompressionratiothatcouldbeused,andtherefore,themoreefficientandpowerfultheenginecouldbe.32裂化問題In1792,crackingwasusedinUKformakingilluminatinggas.1912,Burtonprocesscanmake35%gasolineoutofcrudeoil.Thecrackedfuelsgenerateresinousandgummymaterialinpipelines,causingcorrosionproblem.Theanti-knockpropertiesofcrackedfuelisnotappreciatedinthebeginning.Tetraethylleadisfoundtobegoodatresistingdetonationandoverheatingproblems.NavyintroducedTELin1926.1935,100octaneaviationgasolineintroducedinKleinpaper.33噴氣燃料MostofjetenginesdevelopedbeforetheendofworldwarIIutilizedordinarykeroseneasafuel.(Duetoavailability.Gasolineismilitarygoodsundercontrol.)Whittlehadconsidereddieselfuel,butkerosenewaschosenforflighttestingbecauseitslowfreezepoint.JP-1,aconventionallampburningkerosenewith-40Ffreezepoint.(1944)(Blowoutandreignitiondifficulties)JP-2,awide-cutfueltoexpandsupplies.(itsviscosityisunstable,riskofflammabilitybetween20and80Fatsealevel).JP-3andJP-41946,NACAevaluateFuelAandFuel-BFuelAislabeledasJP-3,withavailabilityof48%.FuelBisa100FflashpointkerosenesimilartoJP-1.Highvolatilityisabigproblemforenginesrunningat30,000feethigh.Finally,itisdecidedtolowerthevaporpressurefrom7psiato3psia,reducingevaporationlossesathighaltitudetoaverylowlevel.Thiswide-cutfuelisJP-4.35JP-4andJP-5JP-4istypicallycontains50to60%gasoline,andtheremainderiskerosene.Theprimaryadvantageofthewidecutisthegreatlyincreasedavailabilityoftheresultingfuel.USnavyuseaviationgasoline(JP-4)forturbojetaircraft.Soon,itlearnedthattheleadinthefuelwasattackingtheenginehotsectioncomponents.1952,“jetmix”,JP-5isdesignedwithahighflashpointkerosene.JP-5hasaminimumflashpointof140F,forship-boardsafetyreasons.Tomaximizeavailabilityofthisfuel,theNavyselectedamaximumfreezepointof-50F.Becausemissionisshort,whiletheseahasalargethermalmass(reservoir).JP-6Forsupersonicflight,JP-6wasdevelopedin1956.ItisakerosenebasedfuelsimilartoJP-5,butwithalowerfreezepointandimprovedthermalstability.JP-6’svaporpressureof0.5psiat100Fwasconsiderablylowerthanthe3psiofJP-4.JP-6’savailabilityis30%ofJP-4.U2JPTS(Thermallystablejetfuel)1956,withJFA-5(jetfueladditive5)37JP-7andJP-8SR-71,Mach-3speed,highheatofcombustion,paraffinsandcycloparaffins,JP-7,high-freezepoint(-46F)becauseofaerodynamicheating.CombatexperienceobservedduringtheVietnamwar,revealedthattheUSAFaircraft,usehighlightvolatileJP4hashighercombatlossesthanUSNaircraft,uselowervolatilityJP5.CrashdataindicatedthattheprobabilityofapostcrashfireforJP4isnearly100%,muchhigherthanwithakerosenefuelsuchasJP5orcommercialJetA.Ground-handlingdevice.JP-8wasdevelopedtoprovideasafer,kerosenebasedjetfuel(similartocommercialjetA-1)forAirForce.Itwasdevelopedtohaveadequateavailabilityandanacceptablefreezepoint(-47C).USAFuseJP-8forbattlefielduse.USNretainsJP-5astheshipboardfuelofchoice.JP-8+100Athightemperaturesthefueltendstobecomeunstableandprecipitatescarbonaceousmaterials.Oxygendissolvedinthefuelreactswithotherfuelcomponentstoformadditionalcarbonadoesmaterial.Fuelsystemandenginedesignersgenerallytrytorestrictthetemperatureoft