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Development of a Small Scale Continuous Hydrolysis Process for Drop-In Biofuel Production.

机译：小型连续水解工艺的开发，用于直接生产生物燃料。

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摘要

Drop-in biofuel production for replacing traditional liquid transportation fuel can be accomplished by converting oils and fats, which are composed mostly triglycerides, into high quality free fatty acid (FFA) and then turning the hydrolyzed FFA into long-chain hydrocarbons through deoxygenation. A small scale thermal hydrolysis of fats and oils in continuous mode is presented in this study with high temperature (250°C∼270°C) and with high pressure in order to suppress the vaporization of liquid reactants. Countercurrent water and lipid flows provided mass transfer and enhanced mixing. Preheating water and oil inflow reduced heat exchange between the inflows and the reactants, and this offered 44% more FFA yield than non-preheating. Increasing reaction temperature improved water solubility in lipid phase and accelerated hydrolysis reaction. Higher excess water also provided better replacement for glycerol content in sweet water and resulted in a better FFA yield. The mass yield, calculated from the reactions with commercial off-shelf canola oil, camelina oil as well as algal oil, was approximately 89% ∼ 93%. Moreover, the energy conversion efficiency is determined to be 75.66%.;In order to minimize the energy input and reaction time, and refine the glycerol refinery for use as an energy source, sweet water formed from the continuous hydrolysis process was recovered. Superheated steam, generated by heating the sweet water above the boiling point of water at the reaction pressure, was injected into the hydrolysis system. This resulted in a high yield of FFA without preheating water and oil as well as at low reactor temperatures and low water-to-oil ratios. Within 300 minutes process time, glycerol was concentrated from 2∼3% (from the reactor) to 5.5% (from the glycerol concentrator), and was expected to increase with extended reaction time. The high enthalpy of the steam and refined glycerol gave 78.64% of energy conversion efficiency, which was 2.98% more than the normal water/oil injection method.;The experimental data allowed the use of two famous methods for determining thermochemical properties; Peng-Robinson departure functions and the Joback group contribution method gave the kinetic model of the continuous hydrolysis reaction, including four equilibrium constants and eight rate constants of the reaction steps. The results provided the activation energy for all forward and reverse reactions under a variety of reaction temperatures. In addition, the results indicated that diglycerides (DG) in the lipid feedstock reduce the induction period for hydrolysis. Moreover, mass balance was found to be conserved by observing uniform carbon distribution. The results from kinetic modeling of hydrolysis, coupled with thermophysical and thermochemical properties as well as liquid flow behavior, were used to develop a CFD model using ANSYS-CFX software. By showing good agreements with experimental data, the concentration distribution of every component of hydrolysis was predicted.;FFA product from continuous hydrolysis reaction, composed of palmitic, oleic, linoleic, linolenic, stearic, arachidic and behenic acids, was fed into a catalytic fed-batch deoxygenation process at an average rate of 15.5 mmoles/min. With a constant temperature of 300°C and a constant pressure of 19 bar and 100g of 5% Pd/C catalyst in H2 and He atmosphere, the liquid product, contained mostly heptadecane, was a drop-in replacement for petroleum diesel fuel.
机译：通过将主要由甘油三酸酯组成的油脂转化为高质量的游离脂肪酸（FFA），然后通过脱氧将水解后的FFA转化为长链烃，可以完成用于替代传统液体运输燃料的直接生物燃料生产。为了抑制液体反应物的汽化，本研究提出了在高温（250°C〜270°C）和高压下以连续模式进行的小规模的油脂热连续水解。逆流的水和脂质流提供了传质并增强了混合。预热水和油流入减少了流入物和反应物之间的热交换，与非预热相比，FFA的收率提高了44％。提高反应温度可改善脂质相中的水溶性，并加速水解反应。较高的过量水还可以更好地替代甜水中的甘油，从而提高FFA产量。由与现成的低芥酸菜子油，山茶油和藻油的反应计算得出的质量产率约为89％〜93％。此外，确定能量转化效率为75.66％。为了最小化能量输入和反应时间，并精制用作能量来源的甘油精制厂，回收了由连续水解过程形成的甜水。通过将甜水在反应压力下加热到水的沸点以上而产生的过热蒸汽被注入到水解系统中。这导致在不预热水和油的情况下以及在低反应器温度和低水油比的情况下实现了高FFA收率。在300分钟的处理时间内，甘油从2％至3％（从反应器中）浓缩至5.5％（从甘油浓缩器中），并有望随着反应时间的延长而增加。蒸汽和精制甘油的高焓提供了78.64％的能量转换效率，比普通的注水/注油方法高2.98％。实验数据允许使用两种著名的方法来测定热化学性质。 Peng-Robinson偏离函数和Joback基团贡献方法给出了连续水解反应的动力学模型，包括四个平衡常数和八个反应步骤速率常数。结果提供了在各种反应温度下所有正向和反向反应的活化能。另外，结果表明脂质原料中的甘油二酸酯（DG）减少了水解的诱导期。而且，发现通过观察均匀的碳分布可以保持质量平衡。水解动力学建模的结果，结合热物理和热化学性质以及液体流动行为，被用于使用ANSYS-CFX软件开发CFD模型。通过与实验数据的良好吻合，预测了水解各组分的浓度分布。连续水解反应的FFA产物由棕榈酸，油酸，亚油酸，亚麻酸，硬脂酸，花生酸和山hen酸组成，送入催化进料分批脱氧过程的平均速率为15.5 mmoles / min。在H2和He气氛中，在300°C的恒定温度和19 bar的恒定压力下以及100g的5％Pd / C催化剂中，主要包含庚烷的液态产物是石油柴油的直接替代品。

著录项

  • 作者

    Wang, Wei-Cheng.;

  • 作者单位

    North Carolina State University.;

  • 授予单位 North Carolina State University.;
  • 学科 Engineering Chemical.;Engineering Mechanical.;Engineering Petroleum.
  • 学位 Ph.D.
  • 年度 2011
  • 页码 185 p.
  • 总页数 185
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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