本文選題：生物柴油 + 化學(xué)動(dòng)力學(xué)��； 參考：《南昌大學(xué)》2015年碩士論文

【摘要】：生物柴油具有含氧10%~15%、動(dòng)力性和經(jīng)濟(jì)性好、可再生性等優(yōu)點(diǎn),柴油機(jī)燃用生物柴油,大大降低了柴油機(jī)排放,特別是碳煙的排放,可以很好的緩解日益嚴(yán)重的能源危機(jī)和環(huán)境危機(jī)�！熬|(zhì)壓燃、低溫燃燒”本質(zhì)上是湍流混合與化學(xué)動(dòng)力學(xué)耦合作用的有限反應(yīng)速率的化學(xué)動(dòng)力學(xué)理論。深入研究生物柴油燃燒化學(xué)動(dòng)力學(xué)對(duì)于發(fā)展這一新技術(shù)具有重大推進(jìn)作用。本文首先構(gòu)建了生物柴油替代物化學(xué)動(dòng)力學(xué)模型,利用CHEMKIN PRO射流反應(yīng)器模型對(duì)生物柴油替代物高低溫反應(yīng)動(dòng)力學(xué)進(jìn)行研究。替代物脂肪酸甲酯低溫階段主要通過OH自由基脫氫生成烷酯基,烷酯基發(fā)生一次加氧、異構(gòu)化、二次加氧、分解生成OH活性基和含氧組分的低溫鏈分支反應(yīng)。構(gòu)建了主要組分高低溫反應(yīng)路徑圖,從鍵能、環(huán)張力和反應(yīng)勢(shì)壘等角度分析了甲酯基及C=C對(duì)生物柴油燃燒氧化特性的影響,分析了脂肪酸甲酯氧原子遷移歷程。利用均質(zhì)密閉反應(yīng)器模型對(duì)生物柴油著火延遲進(jìn)行計(jì)算,分析了初始溫度、壓力、當(dāng)量比以及C=C對(duì)生物柴油滯燃特性影響的反應(yīng)動(dòng)力學(xué)機(jī)理。脂肪酸甲酯組分長達(dá)18~20個(gè)碳原子的直碳鏈結(jié)構(gòu)及含氧甲酯基特殊結(jié)構(gòu)使得生物柴油十六烷值要比石化柴油高,反應(yīng)系統(tǒng)OH活性組分濃度峰值提前出現(xiàn)致使著火提前。C=C的存在影響了鄰近碳原子處的C-H及C-O2鍵離解能,進(jìn)而影響其脫氫反應(yīng)、一次加氧有效性及低溫鏈分支反應(yīng),而且C=C數(shù)量越多以及C=C位置越靠近脂肪族碳鏈中心位置對(duì)低溫活性的抑制作用越大,滯燃期越長。最后構(gòu)建了生物柴油多環(huán)芳香烴PAHs生成與氧化動(dòng)力學(xué)模型,利用反射激波管模型對(duì)混合燃料PAHs生成進(jìn)行模擬。隨著生物柴油體積分?jǐn)?shù)的增加,燃燒過程O、OH自由基峰值濃度增大,促使更多的C2H2、C3H3被氧化形成穩(wěn)定的CO2。另外,甲酯基中非羰基與羰基氧使更多的碳原子在低溫階段轉(zhuǎn)化為穩(wěn)定的CO2,導(dǎo)致了C2H2、C3H3生成量減小,抑制了第一個(gè)苯環(huán)以及PAHs的形成。而C=C使生物柴油低溫燃燒過程小分子不飽和組分生成量增加,促進(jìn)C2H2、C3H3的生成,導(dǎo)致PAHs的生成量增加。
[Abstract]:Biodiesel has many advantages, such as high oxygen content, good power and economy, reproducibility, and so on. Diesel engines burn biodiesel, which greatly reduces diesel engine emissions, especially soot emissions. It can alleviate the increasingly serious energy crisis and environmental crisis. "homogeneous compression ignition, low temperature combustion" is essentially a theory of chemical kinetics of a finite reaction rate coupled with turbulent mixing and chemical dynamics. The further study on the combustion chemistry kinetics of biodiesel is very important for the development of this new technology. In this paper, the chemical kinetics model of biodiesel substitutes was constructed, and the kinetics of high and low temperature reaction of biodiesel substitutes was studied by using CHEMKIN PRO jet reactor model. In the low temperature stage of the substitute fatty acid methyl ester, the alkyl ester group is mainly formed by the dehydrogenation of OH radical, and the alkyl ester group is oxidized, isomerized, oxygenated twice, decomposed to form OH active group and oxygen containing components. The high and low temperature reaction path diagram of main components was constructed. The effects of methyl groups and C on the combustion and oxidation characteristics of biodiesel were analyzed from the point of view of bond energy, ring tension and reaction barrier, and the oxygen atom migration mechanism of fatty acid methyl ester was analyzed. The ignition delay of biodiesel was calculated by using a homogeneous airtight reactor model. The reaction kinetics mechanism of the effects of initial temperature, pressure, equivalent ratio and Con C on the retarded combustion characteristics of biodiesel was analyzed. The cetane number of biodiesel is higher than that of petrochemical diesel because of the straight carbon chain structure of 18 ~ 20 carbon atoms of fatty acid methyl ester and the special structure of oxygen methyl ester group. The early occurrence of peak concentration of OH active component in the reaction system resulted in the early ignition of .CnC, which affected the dissociation energy of C-H and C-O2 bond near the carbon atom, and further affected the dehydrogenation reaction, the primary oxygenation efficiency and the low-temperature chain branching reaction. Moreover, the higher the amount of C, and the closer the position of C ~ (2 +) to the center of aliphatic carbon chain, the greater the inhibition of low temperature activity and the longer the ignition delay. Finally, the PAHs generation and oxidation kinetics model of biodiesel polycyclic aromatic hydrocarbons was constructed, and the PAHs generation of mixed fuel was simulated by using the reflective shock tube model. With the increase of the volume fraction of biodiesel, the peak concentration of O _ (OH) radical increases during combustion, and more C _ 2H _ 2C _ 3H _ 3 is oxidized to form stable CO _ 2. In addition, methyl ester non-carbonyl group and carbonyl oxygen make more carbon atoms convert to stable CO _ 2 at low temperature, resulting in the decrease of C _ 2H _ 2C _ 3H _ 3 production and the inhibition of the formation of the first benzene ring and PAHs. However, CnC increased the amount of unsaturated fraction of small molecule in low temperature combustion of biodiesel, promoted the formation of C2H2C3H3, and increased the amount of PAHs.
【學(xué)位授予單位】：南昌大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TE667

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本文編號(hào)：1990968