【摘要】：隨著全球能源發(fā)展戰(zhàn)略的調(diào)整,綠色可再生能源在能源產(chǎn)業(yè)發(fā)展中占有越來越重要的地位,并將逐漸代替?zhèn)鹘y(tǒng)石化能源。作為典型的綠色能源,生物柴油近年來備受各個國家和地區(qū)的重視。超臨界低碳醇酯交換反應(yīng)是制備生物柴油的新型工藝,具有綠色、快速、高產(chǎn)、高效等優(yōu)勢。相較間歇型制備工藝,連續(xù)型制備工藝能夠降低生產(chǎn)成本與能源消耗,有利于實(shí)現(xiàn)工業(yè)化生產(chǎn)。為此,本文以超臨界甲醇酯交換反應(yīng)制備生物柴油為研究背景,探討不同反應(yīng)器對連續(xù)過程的影響,優(yōu)化反應(yīng)工藝,并把超臨界萃取技術(shù)與超臨界甲醇酯交換反應(yīng)耦合起來,直接以大豆片為原料,一步法制備生物柴油,確定耦合工藝控制步驟和最佳耦合條件。同時,從理論上計算連續(xù)反應(yīng)動力學(xué)和熱力學(xué)行為,為工藝生產(chǎn)推廣提供理論基礎(chǔ)。主要研究內(nèi)容如下：1.為了縮短系統(tǒng)穩(wěn)定時間,提高酯交換反應(yīng)產(chǎn)率,首先以大豆油為原料分別在盤管式反應(yīng)器、直管式填料床反應(yīng)器內(nèi)進(jìn)行超臨界連續(xù)酯交換反應(yīng)的實(shí)驗研究�？疾炝朔�(wěn)定時間、溫度、壓力、醇油摩爾比、進(jìn)料流量等影響參數(shù)。研究結(jié)果發(fā)現(xiàn),直管式填料床反應(yīng)器的反應(yīng)效果優(yōu)于盤管式反應(yīng)器,穩(wěn)定時間短,產(chǎn)物產(chǎn)率高。在直管式填料床反應(yīng)器內(nèi),當(dāng)條件滿足300℃、22MPa、醇油摩爾比42：1時,系統(tǒng)穩(wěn)定時間為30mmin,甲酯產(chǎn)率為80.26%,鐵絲網(wǎng)填料可連續(xù)重復(fù)使用11次。2.對超臨界萃取耦合酯交換過程進(jìn)行系統(tǒng)研究發(fā)現(xiàn),反應(yīng)達(dá)到穩(wěn)定之前,反應(yīng)過程是耦合工藝的控制步驟,反應(yīng)穩(wěn)定之后,則萃取過程是控制步驟。因此,在研究反應(yīng)器和反應(yīng)過程的基礎(chǔ)上,對萃取過程進(jìn)行優(yōu)化。發(fā)現(xiàn)在超臨界CO2中添加適量夾帶劑正己烷可以顯著提高大豆片出油率,具體條件為20g分層填料0.4mmm厚大豆片、40℃、20MPa、CO2與正己烷質(zhì)量比21：1,120mmin后萃取率可達(dá)到99.99%。3.發(fā)現(xiàn)超臨界萃取夾帶劑正己烷對超臨界酯交換反應(yīng)起到強(qiáng)化作用。綜合考慮操作參數(shù)對甲酯產(chǎn)量和產(chǎn)率的影響情況,優(yōu)化匹配萃取動力學(xué)和反應(yīng)動力學(xué),得到最佳耦合反應(yīng)條件為：萃取溫度40℃、反應(yīng)溫度300℃、壓力18MPa～20MPa、CO2與正己烷質(zhì)量流量比14：1、CO2流量2L/mmin,正己烷流量0.4ml/min。4.為了深入探討在超臨界環(huán)境下連續(xù)酯交換工藝的過程機(jī)理,為未考察的實(shí)驗過程提供推斷依據(jù),有益于擴(kuò)大生產(chǎn)和工業(yè)應(yīng)用,從反應(yīng)動力學(xué)和熱力學(xué)行為方面進(jìn)行研究計算。確定了反應(yīng)速率常數(shù)、平衡常數(shù)、大豆油-甲醇臨界參數(shù)和溶解度參數(shù)。
[Abstract]:With the adjustment of global energy development strategy, green renewable energy plays an increasingly important role in the development of energy industry, and will gradually replace the traditional fossil energy. As a typical green energy, biodiesel has been paid much attention by many countries and regions in recent years. Supercritical low carbon alcohol transesterification is a new technology for the preparation of biodiesel, which has the advantages of green, fast, high yield and high efficiency. Compared with batch preparation process, continuous preparation process can reduce production cost and energy consumption, and is conducive to industrial production. Therefore, under the background of supercritical methanol transesterification to prepare biodiesel, the effects of different reactors on the continuous process were discussed, the reaction process was optimized, and the supercritical extraction technology was coupled with the supercritical methanol transesterification reaction. Biodiesel was prepared directly from soybean slices by one step method, and the control steps and the optimum coupling conditions were determined. At the same time, the kinetic and thermodynamic behaviors of continuous reaction are calculated theoretically, which provides a theoretical basis for the popularization of process production. The main contents are as follows: 1. In order to shorten the time of system stabilization and improve the yield of transesterification, the supercritical continuous transesterification was studied in a coil reactor and a straight tube packed bed reactor using soybean oil as raw material. The influences of time, temperature, pressure, molar ratio of alcohol to oil, feed flow rate and so on were investigated. The results show that the reaction effect of the straight tube packed bed reactor is better than that of the coil reactor, the stabilization time is short and the yield of the product is high. In a straight tube packed bed reactor, when the conditions are 300 鈩，

本文編號：2429082