柴油的十六烷值

1、十六烷值(Cetanenumber):十六烷值是指與柴油自燃性相當(dāng)?shù)臉?biāo)準(zhǔn)燃料中所含正十六烷的體積百分?jǐn)?shù)。標(biāo)準(zhǔn)燃料是用正十六烷與2-甲基萘按不同體積百分?jǐn)?shù)配成的混合物。其中正十六烷自燃性好，設(shè)定其十六烷值為100，2-甲基萘自燃性差，設(shè)定其十六烷值為0。也有以2，2，4，4，6，8，8-七甲基壬烷代替2-甲基萘，設(shè)定其十六烷值為15。十六烷值測(cè)定是在實(shí)驗(yàn)室標(biāo)準(zhǔn)的單缸柴油機(jī)上按規(guī)定條件進(jìn)行的。十六烷值高的柴油容易起動(dòng)，燃燒均勻，輸出功率大；十六烷值低，則著火慢，工作不穩(wěn)定，容易發(fā)生爆震。一般用于高速柴油機(jī)的輕柴油，其十六烷值以40-55為宜；中、低速柴油機(jī)用的重柴油的十六烷值可低到35以下。柴油十

2、六烷值的高低與其化學(xué)組成有關(guān)，正構(gòu)烷烴的十六烷值最高，芳烴的十六烷值最低，異構(gòu)烷烴和環(huán)烷烴居中。當(dāng)十六烷值高于50后，再繼續(xù)提高對(duì)縮短柴油的滯燃期作用已不大；相反，當(dāng)十六烷值高于65時(shí)，會(huì)由于滯燃期太短，燃料未及與空氣均勻混合即著火自燃，以致燃燒不完全，部分烴類熱分解而產(chǎn)生游離碳粒，隨廢氣排出，造成發(fā)動(dòng)機(jī)冒黑煙及油耗增大，功率下降。加添加劑可提高柴油的十六烷值，常用的添加劑有硝酸戊酯或已酯。柴油十六烷值;cetanenumber(CN)ofdieselfuel：性質(zhì)：在標(biāo)準(zhǔn)化條件下，指明柴油著火性的約定數(shù)值。在標(biāo)準(zhǔn)試驗(yàn)機(jī)試驗(yàn)中，當(dāng)試驗(yàn)燃料與標(biāo)準(zhǔn)燃料比較具有相同的著火滯后期時(shí)，標(biāo)準(zhǔn)燃料混合物中正

3、十六烷所占的體積百分?jǐn)?shù)即十六烷值。十六烷值高的柴油，著火滯后期較短。其高低因柴油組分不同而異。烷烴十六烷值高，芳烴最低，環(huán)烷烴和烯烴介于兩者之間。當(dāng)十六烷值低于發(fā)動(dòng)機(jī)使用要求時(shí)，會(huì)出現(xiàn)燃燒延遲和燃燒不完全而導(dǎo)致發(fā)生爆震，降低發(fā)動(dòng)機(jī)功率，增大耗油量。十六烷值過高，會(huì)出現(xiàn)燃燒不完全，冒黑煙、增大耗油量。一般來說高速柴油機(jī)要求柴油十六烷值約在4056之間，普通柴油機(jī)在4045之間即可。為了提高十六烷值，可以加入少量十六烷值改進(jìn)劑(如硝酸異戊酯)。十六烷值是柴油規(guī)格的重要指標(biāo)。催化柴油MCI工藝技術(shù)應(yīng)用概況我國(guó)目前的柴汽比較低，柴油數(shù)量滿足不了市場(chǎng)的需求。柴油中的三分之一是催化裂化柴油。催化柴油中含有

4、較多的雜原子化合物、烯烴和芳烴，顏色不好，安定性較差，尤其是十六烷值很低。隨著重油催化裂化技術(shù)的發(fā)展和摻渣量的增加，催化柴油的質(zhì)量問題變得更為突出。當(dāng)前國(guó)內(nèi)外普遍采用的劣質(zhì)催化柴油改質(zhì)手段是加氫精制和加氫裂化。催化柴油加氫精制，是在中、低壓的條件下，進(jìn)行烯烴加氫飽和、脫硫、脫氮及芳烴部分飽和反應(yīng)，可改善其顏色和安定性，而十六烷值提高幅度較小，尤其是加工劣質(zhì)原料的催化裝置，其催化柴油通過加氫精制遠(yuǎn)不能滿足產(chǎn)品對(duì)十六烷值的要求。近幾年開發(fā)的劣質(zhì)柴油中壓加氫改質(zhì)工藝，是中壓下的一種加氫裂化過程，轉(zhuǎn)化率一般為40%60%，雖然其柴油產(chǎn)品的十六烷值較原料可提高1020個(gè)單位，但柴油收率低，化學(xué)氫耗高，不

5、適應(yīng)國(guó)內(nèi)市場(chǎng)的需求。因此，開發(fā)一種既能最大限度提高柴油十六烷值，又能得到較高的柴油收率的劣質(zhì)催化柴油改質(zhì)技術(shù)，是人們普遍關(guān)注的課題。撫順石油化工研究院新開發(fā)的一種提高催化柴油十六烷值的加氫改質(zhì)工藝技術(shù)(MaximumCetanenumberImprovement，簡(jiǎn)稱MCI)。該技術(shù)在吉林化學(xué)工業(yè)公司煉油廠20萬噸/年加氫裝置應(yīng)用成功后，先后有7家煉廠采用該技術(shù)。該技術(shù)不僅能大幅度提高催柴的十六烷值，同時(shí)還能獲得較高的柴油收率，獲得2001年度國(guó)家科技發(fā)明二等獎(jiǎng)，具有顯著的經(jīng)濟(jì)效益和社會(huì)效益，有可觀推廣應(yīng)用前景。催化柴油MCI工藝的理論基礎(chǔ)眾所周知，石油產(chǎn)品的烴類族組成直接影響產(chǎn)品的性質(zhì)。十六

6、烷值是柴油燃燒性能的重要指標(biāo)。柴油餾分中，鏈烷烴的十六烷值最高，環(huán)烷烴次之，芳香烴的十六烷值最低。同類烴中，同碳數(shù)異構(gòu)程度低的烴類化合物具有較高的十六烷值，芳環(huán)數(shù)多的烴類具有較低的十六烷值。因此，環(huán)狀烴含量低，鏈狀烴含量多的柴油具有較高的十六烷值。要提高柴油的十六烷值，必須提高柴油中高十六烷值組分的相對(duì)含量，或采用添加劑。采用十六烷值添加劑，將十六烷值提高23個(gè)單位的成本不太高，但繼續(xù)增加添加劑用量不僅效果不顯著(加到一定比例后十六烷值不再增加)，并且也不經(jīng)濟(jì)。從根本上解決柴油十六烷值低的方法是提高十六烷值較高的烴類組分的相對(duì)含量，方法之一是除去十六烷值較低的芳烴組分(抽提工藝)。這種方法的優(yōu)

7、點(diǎn)是投資低、操作簡(jiǎn)單，但柴油收率低，抽出的芳烴沒有直接的經(jīng)濟(jì)價(jià)值；另一種方法是采用加氫手段，將雙環(huán)和多環(huán)芳烴中的芳環(huán)部分地轉(zhuǎn)化成環(huán)烷烴或進(jìn)而轉(zhuǎn)化成較小分子的芳烴，這種方法中的前者稱為加氫精制，后者稱為加氫裂化。由于催化裂化反應(yīng)的特點(diǎn)，催化柴油中所含的芳烴主要是萘系芳烴。下面以萘在加氫過程的反應(yīng)為例，來說明加氫精制(HT)、加氫裂化(HC)和MCI過程的主要反應(yīng)。在加氫精制條件下，萘只進(jìn)行上述反應(yīng)歷程中的第(1)步，即萘加氫變成四氫萘，四氫萘仍在柴油餾分中，它的十六烷值與萘相比提高不大。因此，加氫精制對(duì)十六烷值改進(jìn)不大。上式中的（1）、（2）、（3）步反應(yīng)為萘在中壓加氫裂化條件下的主要反應(yīng)歷程，

8、由此可見柴油餾分中的萘，在中壓加氫裂化條件下最終轉(zhuǎn)化為苯和丁烷，而從柴油餾分中消失。萘的轉(zhuǎn)化無疑有助于增加柴油的十六烷值，但導(dǎo)致柴油收率下降。從萘的加氫精制和加氫裂化反應(yīng)歷程可看出，這兩種加氫過程對(duì)柴油十六烷值影響的差別。萘在MCI過程的主要反應(yīng)歷程是萘加氫飽和成為四氫萘，然后再開環(huán)。即只進(jìn)行萘加氫裂化反應(yīng)歷程中的（1）、（2）兩步，生成的丁基苯（十六烷值20）仍保留在柴油餾分中，其十六烷值與萘（十六烷值接近于0）相比有較大的提高。MCI反應(yīng)歷程中，由于四氫萘的環(huán)烷開環(huán)打破了加氫精制反應(yīng)中萘加氫生成四氫萘的熱力學(xué)平衡，有利于萘系烴的轉(zhuǎn)化。因此，該過程不僅十六烷值提高幅度較大，而且柴油收率較高。

9、催化柴油（LCO）中雙環(huán)和三環(huán)芳烴，在MCI過程中的反應(yīng)歷程類似于萘，雙環(huán)以上的芳烴只進(jìn)行芳環(huán)飽和和環(huán)烷開環(huán)，其分子碳數(shù)不變。由于雙環(huán)和三環(huán)芳烴轉(zhuǎn)化為烷基苯，柴油中的高十六烷值組分增加，故柴油的十六烷值可得到較大幅度的提高。催化柴油MCI技術(shù)對(duì)催化劑的要求MCI過程的關(guān)鍵是要開發(fā)出一種具有良好芳烴加氫飽和性能和開環(huán)選擇性較高的催化劑。該過程的催化劑應(yīng)具有較高的催化活性，保證有較高的芳烴轉(zhuǎn)化深度，具備較高的選擇性使環(huán)烷開環(huán)而不斷鏈，保證十六烷值提高幅度較大和有較高的柴油收率。此外，還應(yīng)具有較高的抗雜質(zhì)能力和較好的穩(wěn)定性，使之能夠適應(yīng)劣質(zhì)原料和保證長(zhǎng)周期穩(wěn)定運(yùn)轉(zhuǎn)。MCI催化劑理化性質(zhì)牌號(hào)3963形

10、狀三葉草直徑mm1.21.4長(zhǎng)度mm38耐壓強(qiáng)度N/mm13孔容ml/g0.28比表面m2/g200堆積密度g/ml0.820.92將MCI催化劑與一種性能較好的加氫精制催化劑，用同一種原料油，在完全相同的反應(yīng)條件下進(jìn)行了對(duì)比試驗(yàn)，試驗(yàn)結(jié)果見下表。一組典型原料MCI與HT產(chǎn)品性質(zhì)項(xiàng)目原料油MCI產(chǎn)品HT產(chǎn)品密度(20C)g/cm30.91230.86830.8758餾程C50%28426226790%34434133895%357360350運(yùn)動(dòng)粘度（20C）mm2/s3.84.8凝固點(diǎn)C0-4-2硫含量m%0.3210.0200.020氮含量m%0.0800.0035.02.52.0十六烷值

11、（實(shí)測(cè)）25.037.533.6十六烷值增值12.58.6MCI產(chǎn)品與HT產(chǎn)品的雜質(zhì)含量和顏色基本相同，十六烷值的提高幅度有較大的差別，HT過程柴油的十六烷值由25.0提高至33.6，提高了8.6個(gè)單位。而MCI過程由25.0提高至37.5，提高了12.5個(gè)單位，較HT過程提高近4個(gè)單位。催化柴油MCI技術(shù)對(duì)不同原料的適應(yīng)性選用了我國(guó)幾種主要原油的重催柴油，考察了MCI過程對(duì)這幾種原料的改質(zhì)效果。試驗(yàn)原料油主要性質(zhì)原料油大慶催柴大港催柴管輸催柴遼河催柴密度(20C)g/cm30.86800.88820.91230.8949餾程CASTM-D86ASTM-D86ASTM-D86ASTM-D86I

12、BP18414822213410%22520324623230%24523026325950%26625628429170%29328931132190%32532334434495%337332357352EBP343340360361凝點(diǎn)C-11-80-4運(yùn)動(dòng)粘度(20C)mm2/s3.8603.4276.403酸度mgK0H/100ml0.161.45實(shí)際膠質(zhì)mg/100ml83.288.8248.0344.4硫含量|Jg/g1200160032101400氮含量Mg/g8628508001921殘?zhí)?0.090.67顏色色號(hào)5.05.5十六烷值（實(shí)測(cè)）36.724.225.025.1重

13、油催化柴油MCI試驗(yàn)主要工藝條件原料油大慶催柴大港催柴管輸催柴遼河催柴氫分壓MPa6.0平均反應(yīng)溫度C346.7350380350空速h-1(v)1.0氫油體積比500:1700:1800:1800:1柴油收率%98.4197.249597C+液收%100.5999.469899MCI試驗(yàn)產(chǎn)品性質(zhì)原料油大慶催柴大港催柴管輸催柴遼河催柴新標(biāo)準(zhǔn)密度(20C)g/cm30.84640.85350.86830.8719實(shí)測(cè)餾程CASTM-D86ASTM-D86ASTM-D86ASTM-D86GB/T653650%25823926228230090%318310341

14、34335595%330326360352365凝點(diǎn)C-16-14-4-4冷濾點(diǎn)C-5-7運(yùn)動(dòng)粘度(20C)mm?/s3.83.03.85.8酸度mgK0H/100ml81.707實(shí)際膠質(zhì)mg/100ml23.013.440.848.4銅片腐蝕級(jí)11111閃點(diǎn)C766755碘值克碘/100ml0.700.23硫含量Mg/g10034.8502000殘?zhí)?0.3色度號(hào)1.01.0乙酸法殘余物%0.2十六烷值（實(shí)測(cè)）46.236.637.538.145十六烷值增值9.512.212.513.0在中等壓力下，大慶催柴油，大港重催柴油，管輸重催

15、柴油和遼河催柴，經(jīng)過MCI過程均具有較顯著的改質(zhì)效果。有較高的脫雜質(zhì)深度。十六烷值有較大幅度的提高，大慶催柴可提高9.5個(gè)單位，而其余三種原料油均提高十個(gè)單位以上。MCI柴油的其它質(zhì)量指標(biāo)能夠滿足柴油標(biāo)準(zhǔn)。催化柴油MCI工業(yè)應(yīng)用效果MCI技術(shù)的首次工業(yè)應(yīng)用試驗(yàn)是在吉林化學(xué)工業(yè)公司煉油廠20萬噸/年加氫裝置上進(jìn)行。該裝置用FH-5加氫精制催化劑和3963MCI過程專用催化劑。典型工業(yè)原料油性質(zhì)項(xiàng)目工況-1工況-2密度(20C)g/cm30.88240.8798餾程CIBP19320310%21922230%23824150%26026370%28629390%32233195%335346EBP

16、348353凝點(diǎn)C-32-28運(yùn)動(dòng)粘度（20C）mm2/s3.6683.972酸度mgK0H/100ml0.140.14實(shí)際膠質(zhì)mg/100ml83.287.2硫含量|Jg/g941928氮含量Mg/g839936殘?zhí)?0.150.09顏色色號(hào)2.5180C柴油收率%99.7898.60C+液收%5100.8899.58化學(xué)耗氫+漏損氫%1.381.10產(chǎn)品主要性質(zhì)：密度（20C）g/cm30.85840.8604十六烷值39.039.9十六烷值增值12.111.3工業(yè)裝置典型產(chǎn)品性質(zhì)試驗(yàn)編號(hào)工況-1工況-2新標(biāo)準(zhǔn)密度(20C)g/cm30.85840.8604實(shí)測(cè)餾程CASTM-D86AST

17、M-D86GB/T653650%25125730090%31232135595%327336365凝點(diǎn)C-39-29-10冷濾點(diǎn)C-18-10-5運(yùn)動(dòng)粘度(20C)mm?/s3.4853.8273.08.0銅片腐蝕級(jí)111閃點(diǎn)C808155硫含量Mg/g29.629.22000殘?zhí)?0.030.020.3色度號(hào)十六烷值（實(shí)測(cè)）39.039.945十六烷值增值12.111.3工況-1柴油收率為99.78%，C+液體收率為100.88%，工況-1的化學(xué)氫耗與5漏損氫耗共計(jì)1.38%。工況-2柴油收率為98.60%，C+液體收率為99.58%，工5況-1的化學(xué)氫耗與漏損氫耗共計(jì)1.

18、10%（對(duì)原料油）。兩種工況下柴油產(chǎn)品的十六烷值分別為39.0和39.9，但十六烷值提高幅度分別為12.1和11.3，已超過試驗(yàn)研究的9.5和8.5,達(dá)到了MCI預(yù)期的改質(zhì)效果。說明了MCI技術(shù)能夠大幅度提高催化柴油的十六烷值，同時(shí)又能獲得較高的柴油收率，具有加氫精制和中壓加氫改質(zhì)的雙重優(yōu)點(diǎn),有廣泛推廣應(yīng)用前景。BIODIESELWHATISBIODIESEL?Biodiesel(orbiofuel)isthenameforavarietyofester-basedfuels(fattyesters)generallydefinedasthemonoalkylestersmadefromveg

19、etableoils,suchassoybeanoil,canolaorhempoil,orsometimesfromanimalfatsthroughasimpletransesterificationprocess.Thisrenewablesourceisasefficientaspetroleumdieselinpoweringunmodifieddieselengine.HISTORYTheconceptofusingvegetaloilasanenginefuellikelydateswhenRudolfDiesel(1858-1913)developedthefirstengin

20、etorunonpeanutoil,ashedemonstratedattheWorldExhibitioninParisin1900.Unfortunately,R.Dieseldied1913beforehisvisionofavegetableoilpoweredenginewasfullyrealized.RudolfDieselRudolfDieselfirmlybelievedtheutilizationofabiomassfueltobetherealfutureofhisengine.Hewantedtoprovidefarmerstheopportunitytoproduce

21、theirownfuel.In1911,hesaidThedieselenginecanbefedwithvegetableoilsandwouldhelpconsiderablyinthedevelopmentofagricultureofthecountrieswhichuseit.Theuseofvegetableoilsforenginefuelsmayseeminsignificanttoday.Butsuchoilsmaybecomeinthecourseoftimeasimportantasthepetroleumandcoaltarproductsofthepresenttim

22、eRudolfDiesel,1912AfterR.Dieseldeaththepetroleumindustrywasrapidlydevelopingandproducedacheapby-productdieselfuelpoweringamodifieddiesel-engine.Thus,cleanvegetableoilwasforgottenasarenewablesourceofpower.Moderndieselsarenowdesignedtorunonalessviscousfuelthanvegetableoilbut,intimesoffuelshortages,car

23、sandtrucksweresuccessfullyrunonpreheatedpeanutoilandanimalfat.Itseemsthattheupperrateforinclusionofrapeseedoilwithdieselfuelisabout25%butcrudevegetaloilasadieselfuelextenderinducespoorercold-startingperformancecomparedwithdieselfuelorbiodieselmadewithfattyesters(McDonnelKetal.JAOCS1999,76,539).Today

24、sdieselenginesrequireaclean-burning,stablefueloperatingunderavarietyofconditions.Inthemid1970s,fuelshortagesspurredinterestindiversifyingfuelresources,andthusbiodieselasfattyesterswasdevelopedasanalternativetopetroleumdiesel.Later,inthe1990s,interestwasrisingduetothelargepollutionreductionbenefitsco

25、mingfromtheuseofbiodiesel.Theuseofbiodieselisaffectedbylegislationandregulationsinallcountries(KnotheG,Inform2002,13,900).OnFebruary9,2004,theGovernmentofthePhilippinesdirectedallofitsdepartmentstoincorporateonepercentbyvolumecoconutbiodieselindieselfuelforuseingovernmentvehicles.TheEUCouncilofMinis

26、tersadoptednewpan-EUrulesforthedetaxationofbiodieselandbiofuelsonOctober27,2003.Large-volumeproductionoccursmainlyinEurope,withproductiontherenowexceeding1.4milliontonsperyear.WesternEuropeanbiodieselproductioncapacitywasestimatedatabout2millionmetrictonsperyearlargelyproducedthroughthetransesterifi

27、cationprocess,aboutone-halfthereofinGermany(440,000and350,000MTinFranceandItaly,respectively).IntheUnitedStates,by1995,10percentofallfederalvehiclesweretobeusingalternativefuelstosetanexamplefortheprivateautomotiveandfuelindustries.Severalstudiesarenowfundedtopromotetheuseofblendsofbiodieselandheati

28、ngoilinUSA.InUSAsoybeanoilistheprincipaloilbeingutilizedforbiodiesel(about80,000tonsin2003).Detailsmaybeviewedon-linethroughtheNationalBiodieselBoardwebsite.Severalreviewsonsources,production,compositionandpropertiesofbiodieselmaybeconsultedforfurtherinformation:-RamadhasASetal.,RenewableEnergy2004,

29、29,727-742-BajpaiDetal.,JOleoSci2006,55,487-DurrettTPetal.,ThePlantJ2008,54,593-607-JetterRetal.,ThePlantJ2008,54,670-683Asmanyalgalspecieshavebeenfoundtogrowrapidlyandproducesubstantialamountsoftriacylglycerols(oleaginousalgae),ithaslongbeenpostulatedthattheycouldbeemployedtoproduceoilsandotherlipi

30、dsforbiofuels(seereviewin:HuQetal.,ThePlantJ2008,54,621-639).Averyinformativereviewoftheprospectsofusingyeastsandmicroalgaeassourceofcheapoilsthatcouldbeusedforbiodieselmaybeconsulted(RatledgeCetal.,LipidTechnol2008,20,155).Asthemajorbyproductofbiodieselproductionisglycerol,usesforthatbyproducthaveb

31、eeninvestigated.Glycerolcanbethermochemicallyconvertedintopropyleneglycol(ChiuCWetal.,IndEngChemRes2006,45,791),1,3-propanediol(Gonzalez-PajueloMetal.,MetabEng2005,7,329),lipids(NarayanMetal.,IntJFoodSciNutr2005,56,521)andseveralotherchemicals.Amonglipids,itwasshownthatglycerolcanbeusedtoproducedoco

32、sahexaenoicacid(DHA)throughfermentationofthealgaSchizochytriumlimacinum(ChiZetal.,ProcessBiochem2007,42,1537;PyleDJetal.,JAgricFoodChem2008,56,3933).Areviewoftheuseofvegetableoilsasenginefuelsmaybeconsulted(RamadhasASetal.RenewEnergy2007,29,727).ThebookofNitskeWRetal.maybeconsultedforthehistoryofbio

33、diesel(NitskeWR,WilsonCM,RudolfDiesel:Pioneeroftheageofpower)MAKINGBIODIESELWhatisstillwidelyunknownisthatitiseasytomakebiodieselfordieselenginesusingvegetableoiloranimalfat.BiodieselissoldcommerciallyinEurope,AmericaandAustralia.Onasmallscale,vegetableoilisrelativelyexpensive,butusedproductsfromthe

34、cookingindustryisabundantandcaneasilyandcheaplybeconvertedintoabiodieselfuelthatwillmixinanyquantitywithconventionaldiesel.Duringheating,theamountofpolymersintheoilmayincreaseupto15wt%andthusmayhavenegativeinfluenceonfuelcharacteristics.Therefore,theamountofpolymersinwasteoilisagoodindicatorforbiodi

35、eselproduction(MittelbachMetal.JAOCS1999,76,545).Thetransesterificationprocessinvolvesmixingatroomtemperaturemethanol(50%excess)withNaOH(100%excess),thenmixingvigorouslywithvegetableoilandlettingtheglycerolsettle(about15%ofthebiodieselmix).Thesupernatantisbiodieselandcontainsamixtureofmethylatedfatt

36、yacidsandmethanol,thecatalystremainingdissolvedintheglycerolfraction.Industrially,theestersaresenttotheclean-uporpurificationprocesswhichconsistsofwaterwashing,vacuumdrying,andfiltration.Aninsitualkalinetransesterificationwasshowntobeefficientinpreparingfattyacidesters,thesimpleanddirectprocesselimi

37、natingtheexpenseassociatedwithsolventextractionandoilcleanup(HaasMJetal.,JAOCS2004,81,83).Transesterificationmaybeprocessedusingmethanol,ethanol,isopropylalcohol,orbutanol,thecatalystbeingeithersodiumorpotassiumhydroxide.Itwasshownthatthemethanol/oilmolarratioinfluenceslargelytheefficiencyofthereact

38、ionandhasimportantimplicationsfortheoptimalsizeofmethylesterplants(BoocockDGBetal.JAOCS1998,75,1167).OptimizationofmethanolysisofBrassicacarinataoilhasbeenexaminedconsideringthecatalystconcentrationaswellasthereactiontemperature(VicenteGetal.,JAOCS2005,82,899).Variousreactionparametersforthesynthesi

39、sofbiodieselfromsaffloweroilwerestudiedtoimprovethefuelproductionwhichwaswithintherecommendedstandardswith96.8%yield(MekaPKetal.,JOleoSci2007,56,9).Freefattyacidsandtotalglycerol(freeandacylglycerols)caninitiateenginecorrosionandaffecthumanoranimalhealthbyemissionofhazardousacroleinintotheenvironmen

40、t.Accordingly,maximumallowableamountsoffreefattyacidsandacylglycerolsareincludedinthebiodieselspecificationofmostcountries.Forglycerol,amaximumpermissibleconcentrationof0.02wt-%issetbytheEuropeannormaswellasbytheASTMspecification.Therefore,itisnecessarytodeterminetheamountoffreeglycerolinbiodiesel.A

41、mongothers,asimpleandrapidmethodwasdescribedusingHPLCwithrefractometricdetection(HajekMetal.,EurJLipidSciTechnol2006,108,666).AsimpleHPLCmethodusingalight-diffusiondetectorwasproposedtomonitoracyglycerolsandfreefattyacidsconcentrationsinbiodiesel(KittirattanapiboonKetal.,EurJLipidSciTechnol2008,110,

42、422).InformationonthephysicalpropertiesdescribedbythestandardsanddetailsonthestandardreferencemethodsmaybefoundinthepaperbyKnotheG(JAOCS2008,83,823).Itwasexperiencedthat10lofsoybeansproducedabout1.9lofbiodiesel.Aliterofthisfuelcontainsabout35,000BTUs.Iffatsorsolidifiedoilareused,itwillneedtoheatupto

43、50Cthemixturepriortomixingwithmethanolandcatalyst.Iffreefattyacidsarepresent(usedcookingoils),specialpretreatmenttechnologiesarerequired(seewebsite).Amonglipid-richmaterialsoflowvalueissoapstock,aco-productoftherefiningofediblevegetaloils.Thismixtureisgeneratedatarateofabout6%ofthetreatedunrefinedoi

44、l(45MTperyearinUSA).Anefficientprocedureinvolvingacid-catalyzedesterificationofsoapstockhasbeendescribed(HaasMJetal.,JAmOilChemSoc2003,80,97).Theworldbiodieselsourceswerein2002:rapeseedoil(84%),sunflower(13%),soybeanoil(1%),palmoil(1%),andothers(1%).Informationonmakingbiodieselmaybefoundinspecificwe

45、bsites: HYPERLINK HYPERLINK /biodiesel/index.htm /biodiesel/index.htmhttp:/biodieselmake.htmlhttp:/group/Biodiesel/EuropeanBiofuelTechnologyPlatformGeneralbiodesielinformation: HYPERLINK /biodiesel/ /biodiesel/ HYPERLINK / /(thelatestinformationonbiodiesel)Otherresources(discussiongroups): HYPERLINK /group/Biodiesel /group/BiodieselEuropeanBiodieselBoard:Update