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TheChemistryofCoalandTechnologyByDingMing-jieDepartmentofChemicalEngineeringInAugust2009Chapter1CoalasanOrganicSediment22009/08Review:CoalisakindofsedimentaryorganicrockCoalhadoriginatedfromancientplantremains.Verycomplicatedlybiochemicalandphysicochemicalactionshadworkedincoal-formingprocess.Coal-formationhadproceededundercertainclimatic,biological,environmentalandgeologicalconditions.AdefinitionofCoalCoalisakindofsedimentaryorganicrockoriginatingfromancientplantremainsundergonecomplicatedlybiochemicalandphysicochemicalchangesundercertainclimatic,biological,environmentalandgeologicalconditions.32009/08GuidetonewlecturePreludequestionstoCoalasanOrganicSedimentWhichplantremainscouldhavebeenconvertedintocoal?Andwhatprecursorshadbeenexperiencedbeforecoalhadbeenformed?Howistheprocesseslikefromtheoriginstocoal?Contents1Originsofcoal2Precursors(先驱，前体，母体)ofcoal3Coal-formingprocesses（成煤过程，成煤作用）42009/081.TheoriginsofcoalAbriefdescription(pleaserehearsethisparagraph)Coalwasformedfrompartiallydecomposed(已降解的，已腐烂的）(andsubsequently(后来，随后）metamorphosed(变质，变形）)plantdebris(碎片，残骸）whichcollectedinregionswherewaterlogged(浸满水的，涝的）orswampy(沼泽的，湿地的）conditionsprevailed(流行，盛行，占优势）.Theseconditionspreventedcompletedecay(腐烂，降解）ofthedebrisasitaccumulatedandeventually(最后的）ledtothematerialnowascoal.52009/08Ingeneralterms,thedebrisconsistedoftrees,ferns（蕨类植物）,rushes（灯芯草，灌木）,lycopods（石松属植物）,andseveralthousandplantspeciesthathavebeenidentifiedincoalbeds,butitappearsthatnoneofthespeciesidentifiedinmanydifferentcoalsoriginatedinbrackish-water（盐水）locales（区域）.Similartypesofplantremainsmaybefoundinalltypes(ranks（煤阶）)ofcoal，but,ofcourse,therelativeamounts（相对含量）varyconsiderably（相当地，非常地）.Onthisbasis（由此）,itisnotsurprisingthatcoaldiffersmarkedly（显著地）incompositionfromoneparticularseamarenotuncommon,duenotonlytothewidevarietyofplantdebristhatcouldhaveformedtheprecursors（母体，前体）butalsotothemanydifferentchemicalreactionsthatcanoccurduringthematuration（成熟）process.Bytheeyesofcoalchemistry:plants----higherandlowerplants.thelower:unicellular（单细胞的）ormulticellular（多细胞的）fungoids（菌类）andalgaes（藻类）withoutdistinction（区分，分化）ofroots,stemsandleavesthehigher:lichens（苔藓）,ferns（蕨类）,gymnosperm（裸子植物）andangiosperm（被子植物）,etc,andthereisdistinctionofroots,stemsandleaves62009/08Thus,onceplantdebrishasaccumulatedunderthe“correct”conditions,theformationofpeat（泥炭）graduallyoccurs（发生，出现）.Peatisnotactuallyclassifiedascoalbutitis,nevertheless（仍然，不过）,believedtobethatmaterialwhichisformedastheinitialstepintheprocess.However,tobecomecoal,peatmustprogress（前进，进展，经历）throughwhatislooselytermed“coalification”（煤化作用）process.Thecoalificationprocessis,inessence（本质）,theprogressive（渐进的，累进的）changeintheplantdebrisasitbecomestransformedfrompeattolignite（褐煤）andthenthroughthehigherranks（高阶）ofcoal（suchassubbituminous（次烟煤）andbituminous（烟煤）coals）toanthracite（无烟煤）.Thedegreeofcoalificationgenerallydeterminestherankofthecoal,buttheprocessisnotaseriesofstraightforward（简单的，直截了当的）chemicalchanges.Forexample,themetamorphism（变质作用）oftheplantdebrisnotonlyrelieson（＝dependon）geologicaltime（地质年代）butalsoontemperatureandpressure.72009/08Thus,whentheorganicdebris(whichmaybeidentifiedaspeat)isburiedbeneath（在之下）overburden（过载，重压）,variousphysicochemical（物理化学的）processesoccuraspartofthemetamorphosis（变质，变形）.Themajorinfluencesarebelievedtobetheresulting（由此引起的）heatandpressuredevelopedbecauseoftheoverlying（上面堆垛的）sedimentarycover(overburden).Thisleadstochangesintheconstituents（成分，组成）ofthedebrissuchasanincreaseinthecarboncontent,alteration（改变）ofthefunctionalgroups（官能团）,alterationofthevariousmolecularstructuresultimately（finally）resultinginthelossofwater,oxygen,andhydrogenwiththeincreasedresistance（阻力，阻抗，电阻）tosolvents,heat,andoxidation.82009/08Alltheoriesabouttheformationofcoalrequirethattheoriginalplantdebriseliminate（去除，减少，消除）oxygenandhydrogencontinuouslyundertheprevailing（优势的）conditions,ultimatelyleadingtoaproductcontainingapproximately（大约）90%w/wcarbon,i.e.,anthracite（无烟煤）.Inorderforthematuration（成熟）toproceed,chemicalprinciples（原理，法则）requirethatoxidationreactionsbecompletelyinhibited（禁止）.However,intheearlystages（早期阶段）ofcalcification,microorganisms（微生物）mayplayanimportantroleand,somewhatparadoxically（看似矛盾而实际地）,theymayinteractwiththeplantmaterialunderaerobic（需氧的）conditionsaswellasunderanaerobic（厌氧的）conditions.Theformationofcoalundertheslowconditionsgenerallyreferredto（指的是）asgeologicaltime（地质时期）may,nevertheless（不过，仍然）,beregardedas（被认为是）occurringintheabsenceof（缺少的）oxygen,thereby（因此）promoting（促进，提高，提升）theformationofhighlycarbonaceous（碳质的，高碳的）moleculesthroughlossesofoxygenandhydrogenfromtheoriginalorganicmolecules.92009/08SummaryPlantremains102009/082.PrecursorsofcoalLignins（木质素）Carbohydrates（碳水化合物）Proteins（蛋白质）Lipoids（类脂）:Oils,fats,andwaxesTheconstituents（组成，组分）oftheorganicportionoftheoriginalplants,whichultimately（最终，最后）transformed（转化）intocoal,hasgreatinfluenceon（对有极大影响）thefinishedcoalstructureanditscomposition.Soitisnecessarytomakecompleteunderstandingoftheconstituentsoftheorganicportionofplants.Themakeupoftheorganicportionofplan