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题名	溶剂萃取法回收发酵废水中的丙酸
作者	王康
学位类别	博士
答辩日期	2009-06-05
授予单位	中国科学院过程工程研究所
授予地点	过程工程研究所
导师	刘会洲
关键词	溶剂萃取 丙酸 磷酸三丁酯 N1923 废水 萃取平衡常数
其他题名	Solvent Extraction for Recovery of Propionic Acid from Fermentation Wastewater
学位专业	化学工艺
中文摘要	厌氧法发酵生产维生素B12的过程中会产生副产物丙酸，回收这部分丙酸既能实现资源的有效回收利用，又能降低废水的处理难度，因此，研究从发酵废水中有效回收丙酸的工艺是十分重要的工作。 络合萃取法是一种基于可逆络合反应的溶剂萃取分离方法，它具有高效性、高选择性、二次污染小、操作成本低、溶剂再生简单等一系列优点。利用络合萃取法可能为极性有机物稀溶液的分离提供一条新的分离路径。 论文首先以模拟体系下的丙酸溶液为研究对象，选用了伯胺(N1923)和磷酸三丁酯( tributyl phosphate, TBP)为萃取剂，研究了有机相中萃取剂的含量、温度、水相初始pH值对两种萃取剂萃取丙酸性能的影响，优化了萃取操作的工艺条件。测定了N1923和TBP萃取丙酸的萃取反应平衡常数，并研究了稀释剂、温度对萃取平衡常数的影响，实验结果表明两种萃取剂萃取丙酸的反应都为放热反应。在N1923萃取丙酸的过程中，稀释剂通过其溶解能力以及给质子能力影响着萃合物稳定性，从而影响了萃取反应平衡常数。而在TBP萃取丙酸过程中，由于给质子型溶剂与TBP之间的氢键作用，使得TBP萃取丙酸的萃取反应平衡常数降低，而以其他类型溶剂为稀释剂时，丙酸的萃取反应平衡常数保持不变。 考察了无机酸根的存在对萃取剂萃取性能的影响，研究发现以TBP为萃取剂，当溶液中存在无机酸根时，TBP对丙酸的萃取性能有所提高，而且有机相中不会萃入无机酸根。而以N1923为萃取剂时，无机酸根的存在会降低丙酸的萃取率，而且有机相中萃入无机酸根，通过傅立叶变换红外光谱以及冷冻蚀刻透射电镜表征发现，无机酸根是通过氢键作用进入有机相，而且在有机相内部形成了反胶团的结构。 研究了碱水反萃取以及减压蒸馏两种溶剂再生的方式，考察了两种再生方式的操作参数，通过溶剂的循环套用实验以及傅立叶变换红外光谱表征证实了两种溶剂再生方式的可行性，在此基础上提出了萃取-碱水反萃和萃取-减压蒸馏两种工艺路线。 研究了实际发酵废水的性质，其成分复杂，具有低的表面张力、稍高的黏度。采用调低pH的方式对发酵废水进行预处理，从而去除其中易于产生乳化的蛋白质、培养基残渣、高分子表面活性剂等，考察了N1923和TBP在实际体系中的萃取性能，以及它们再生后的萃取性能，并且在实际体系了测试了两种工艺路线，实验结果表明：萃取-碱水反萃路线最终得到的产品是钠盐的形式，进一步的分离纯化困难；萃取-减压蒸馏路线流程短，最终产品是纯度较高的丙酸。 在放大实验中，选用TBP为萃取剂，以振动筛板塔为萃取设备，考察了振动筛板塔的结构参数，如孔径、开孔率，以及操作参数，如比负荷、振幅、振动频率等对其流动传质性能的影响。在此基础上，采用双振动筛板塔联用以及振动筛板塔和精馏塔联用分别考察了萃取-反萃路线和萃取-减压蒸馏路线。
英文摘要	Together with anaerobic fermentation producing Vitamin B12, propionic acid is also produced as a byproduct. The propionic acid should be recovered to get the resources recycled and to reduce the difficulty of the wastewater treatment. So it is necessary to develop an effective separation process to recover propionic acid from wastewater. Reactive reaction is an extraction separation method based on reversible chemical complexation reaction. It is a new attractive method to recover organics from aqueous solution, which has a number of advantages such as high effectiveness, high selectivity, low secondary pollution, low running cost, good regenerability and so on. In the dissertation, primary amine (N1923) and tributyl phosphate (TBP) were selected as extractants to recover propionic acid in the simulated aqueous propionic acid solution, the influence of the operation parameters, such as the concentration of extractant in the organic phase, temperature and initial pH of aqueous solution on the extraction behavior was investigated, and the operating parameters were optimized. The reactive extraction equilibrium constants for extracting propionic acid with N1923 and TBP were determined, and the influence of diluent and temperature on the reactive extraction equilibrium constants was investigated. The extractive extractions of both extractants are exothermic. During the extraction process of N1923 towrds propionic acid, the diluent affects the stability of the complex through its solvation ability and specific hydrogen bonding with the complex, furthermore the reactive extraction equilibrium constants were influenced. When TBP was used as extractant, because of the hydrogen bond between protogenic solvent and TBP, the reactive extraction equilibrium constants of TBP decreased in the protogenic solvent, when other types of solvents were used as diluent, the reactive extraction equilibrium constants kept unchanged. The influence of the presence of inorganic acid radical in the aqueous phase on the extraction behavior was also investigated. The addition of inorganic acid radical in the aqueous phase can enhance the extraction of TBP towards propionic acid, without importing the inorganic acid radical into the organic phase. When N1923 was used as extractant, the addition of inorganic acid radical decreased the extraction yield of propionic acid. Besides, the inorganic acid radical was extracted into the organic phase. The study of FTIR spectra and freeze fracture transmission electron microscopy (FFTEM) indicated that reversed micelles were formed in the organic phase, and the inorganic acid radical was extracted into organic phase by the interaction of hydrogen bond. Two approaches for regeneration of extractant, back-extraction using NaOH and vacuum distillation, were studied. The FTIR characterization and extraction behavior of the regenerated extractant confirmed the feasibility of the two methods. As a result, two process routes, extraction-backextraction and extraction-distillation, were proposed. Properties of the wastewater were investigated. The composition of the wastewater is very complex. It has low surface tension and high viscosity. The wastewater was pretreated by acidification to remove the protein, residue of culture medium, polymer surfactants, which is easily to cause emulsion. The extraction behaviors of N1923 and TBP were investigated by the real wastewater, and the two methods for the regeneration of the extractant were also examined, at last the two proposed process routes were tested. In the extraction-backextraction process, the final product was in the form of salt, which is difficult for the further purification. In the extraction-distillation process, propionic acid with high purity was obtained as the final product. In the scale-up test, TBP was chosen as extractant, and reciprocating plate column was used as extraction equipment. The influences of the structure and operation parameters, such as pore size of plate, packing free ratio, loading ratio, amplitude, frequency, on the mass transfer were studied. Finally, the two process route was achieved successfully with reciprocating plate column and distillation tower.
语种	中文
公开日期	2013-09-16
页码	143
内容类型	学位论文
源URL	[http://ir.ipe.ac.cn/handle/122111/1311]
专题	过程工程研究所_研究所（批量导入）
推荐引用方式 GB/T 7714	王康. 溶剂萃取法回收发酵废水中的丙酸[D]. 过程工程研究所. 中国科学院过程工程研究所. 2009.

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