膜蒸馏过程的CFD模拟

文章基于膜蒸馏热质传递机理建立了二维CFD模型。利用商用CFD软件FLUENT模拟了平板膜组件中的膜蒸馏过程,模拟结果与文献实验值较吻合,相对平均偏差为6.0%。利用所建CFD模型,模拟了不同料液温度、浓度及流速下的膜蒸馏过程。通过分析不同操作条件下的渗透通量变化、膜组件内的温度场和浓度场分布及过饱和度分布,确定了膜蒸馏过程的适宜操作条件:对于较低浓度进料(即料液侧进口Na Cl质量分数为0.15),可采用低流速(0.02~0.06 m/s)操作条件;而较高浓度料液的浓缩(即Na Cl质量分数为0.25)时,应采取高料液侧流速操作(≥0.07 m/s)以避免膜表面Na Cl过饱和结晶析出影响膜蒸馏正常进行。     

Aspen Hysys在油田净化商品油蒸馏装置的应用

针对让那若尔油田油气处理厂自用油需求及气候条件等特点,采用Aspen Hysys流程模拟软件对净化商品油蒸馏工艺进行模拟,考察了塔板数、侧线抽出位置、进料温度、回流比、塔操作压力、塔底汽提蒸汽用量及侧线汽提蒸汽用量等因素对蒸馏效果的影响,并得到了相应的影响规律。又通过进料温度和回流比的正交模拟试验结合现场的实际条件优化了工艺条件,确定了冬、夏两季的加工方案工艺条件。     

原油蒸馏过程的模拟与分析

采用ASPENPLUS软件的PetroFRAC模块对原油蒸馏过程进行模拟,模拟得到的总物料平衡、操作条件和产品质量等结果与工厂生产装置数据较为一致。通过灵敏度分析发现初馏塔和常压塔塔顶馏出量、常压塔塔底蒸汽量和侧线汽提蒸汽量这几个显著影响拔出率的因素,为原油蒸馏操作优化方案的制定奠定基础。     

分子蒸馏过程数学建模及模拟验证

建立了分子蒸馏过程径向和轴向的二维数学模型,采用CFD方法对DBP-DBS混合物系的分离过程进行模拟计算,分析了蒸馏温度和进料速率等操作条件对蒸馏过程的影响。将模拟结果与文献中采用BGK模型计算得到的结果进行对比,两者具有较好的吻合性,验证了模型的合理性。     

蒸馏过程中进料情况的选择

一、前言蒸馏过程受许多因素的影响,诸如流程、设备、操作条件(压力;温度;进料、馏液及釜液的成分;进料情况;回流比等)、控制方法等。同时这些因素又大都互相于扰,因此在生产实践中很难掌握。本文就这些因素之—,即进料情况的选择问题加以讨论。     

应用分子蒸馏技术提纯α-亚麻酸

本文应用刮膜式分子蒸馏装置对亚麻酸的提纯进行了研究.考察了蒸馏温度、系统压力、进料速率、进料温度等操作因素对亚麻酸产品纯度与收率的影响.得到了分子蒸馏技术提纯亚麻酸的工艺条件.     

减压膜蒸馏热量回收过程研究

减压膜蒸馏作为一种新型的脱盐技术在海水淡化和高盐废水处理等方面具有广泛的应用价值。针对解决减压膜蒸馏过程中热量消耗大的问题展开了探索性研究,研制出了1套三级热量回收式减压膜蒸馏组件, 考察了不同操作条件对热量回收利用率的影响。研究结果表明,所设计的热量回收式组件能够有效回收利用减压膜蒸馏过程中的蒸汽潜热,而进料液温度、进料液流速和蒸汽透过侧真空度等操作条件都对其热量回收利用率具有一定程度的影响。为进一步提升减压膜蒸馏热量回收效率的研究和降低运行成本工艺技术的开发奠定了基础。     

酒精蒸馏中杂醇油的分离过程模拟与优化

以酒精五塔蒸馏工艺为依据,利用流程模拟软件Aspen Plus建立对酒精蒸馏中杂醇油分离回收过程的模型,模拟结果与实际工业过程数据相符。针对工艺中关于杂醇油的操作参数做出分析和优化,模拟结果可为生产实践中调节各操作参数对杂醇油分离回收效率的影响提供参考和借鉴。     

色谱模拟蒸馏方法测定蒽油的馏程和初馏点

针对蒽油馏程和初馏点测定所采用的传统手工蒸馏法污染大、周期长、操作复杂的缺点,选择合适的色谱条件,通过将色谱数据与手工蒸馏数据进行统计分析,成功得出了两者间的关联公式,利用该公式将色谱检验数据推算成馏程和初馏点,计算数据与实际手工蒸馏结果十分吻合,实现了色谱检验模拟手工蒸馏。     

膜蒸馏技术最新研究应用进展

膜蒸馏是一种热驱动的新型分离技术,可使蒸汽分子在膜两侧的压力梯度作用下通过膜孔迁移至膜外侧并冷凝下来。本文简要介绍了膜蒸馏的热质传递原理以及直接接触式、气隙式、气扫式、真空式等几种主要膜蒸馏装置的特点。综述分析了膜蒸馏的相关研究进展,包括:膜蒸馏的操作及膜特性参数的影响机理研究;更多高性能的膜材料的研制;对膜污染在工艺与操作参数方面的改进;通过能源利用与组件优化强化膜蒸馏过程等。概述了膜蒸馏在海水脱盐制备纯水、食品工业中果汁浓缩及酒精发酵、化学可挥发性物质的分离以及有毒有害废水处理方面的最新应用。最后,进一步指出过程参数的综合影响、膜材料的商业化、膜组件设计以及过程热效率是目前阻碍膜蒸馏工业化应用的主要问题。展望了加强能源研究、专注于商业用膜的研发、较多关注于其他膜蒸馏过程以及系统角度的优化分析是膜蒸馏技术未来的发展方向。     

Evidence for a compound in Comstock-Kellog glands modulating premating behavior in male desert locust,Schistocerca gregaria

The Comstock-Kellog glands in adult females of certain acridid species, including the desert locust, Schistocerca gregaria have been implicated as a source of volatiles that play a role in mating behavior. A dichloromethane extract of the glands was analyzed for metabolites by gas chromatography, coupled gas chromatography–electroantennographic detection, and mass spectrometry. Coupled gas chromatography–electroantennographic detector (GC-EAD) analysis revealed a component that elicited an electroantennogram response from the antenna of adult male S. gregaria. The compound was identified by GC-MS as pentanoic acid. The levels of the compound in the gland extract varied with age of female locust; it was present in detectable amounts only in 14- to 16-day-old females. In bioassays, pentanoic acid significantly stimulated pre-mating behavior in male desert locust. These results are discussed in relation to the biology of the locust.     

GC-MS法检测车用汽油中的甲缩醛、碳酸二甲酯和N-甲基苯胺

车用汽油检测存在多种方式,GC-MS法是较为常见的一种,该方式具有检测精确率高、操作简单等优势。对GC-MS法检测车用汽油中的甲缩醛、碳酸二甲酯和N-甲基苯胺进行了研究。首先简单介绍了GC-MS法,继而设计了实验方案,最后通过对实验结果分析的方式,提出了文章研究结论。     

Gas chromatographic quantification of fatty acid methyl esters: Flame ionization detection vs. Electron impact mass spectrometry

The determination of FAME by GC is among the most commonplace analyses in lipid research. Quantification of FAME by GC with FID has been effectively performed for some time, whereas detection with MS has been used chiefly for qualitative analysis of FAME. Nonetheless, the sensitivity and selectivity of MS methods advocate a quantitative role for GC-MS in FAME analysis—an approach that would be particularly advantageous for FAME determination in complex biological samples, where spectrometric confirmation of analytes is advisable. To assess the utility of GC-MS methods for FAME quantification, a comparative study of GC-FID and GC-MS methods has been conducted. FAME in prepared solutions as well as a biological standard reference material were analyzed by GC-FID and GC-MS methods using both ion trap and quadrupole MS systems. Quantification by MS, based on total ion counts and processing of selected ions, was investigated for FAME ionized by electron impact. Instrument precision, detection limits, calibration behavior, and response factors were investigated for each approach, and quantitative results obtained by each technique were compared. Although there were a number of characteristic differences between the MS methods and FID with respect to FAME analysis, the quantitative performance of GC-MS compared satisfactorily with that of GC-FID. The capacity to combine spectrometric examination and quantitative determination advances GC-MS as a powerful alternative to GC-FID for FAME analysis.     

未知涂料中化学成分的分析

采用红外光谱、气质联用仪对一种未知涂料的化学成分进行检测分析,对涂料的红外光谱进行解析、综合定性,并用气质联用数据进行验证,确定出涂料的溶剂及基料.     

水杨酸对气相色谱-质谱法检测化妆品中苯酚的影响

2007版《化妆品卫生规范》规定,使用HPLC-DAD法检测化妆品中的苯酚,如有阳性结果,必须用GC-MS法进行验证。采用GC-MS法对含有水杨酸的化妆品进行检测,考察水杨酸对苯酚测定的影响。结果表明,水杨酸对热不稳定,在GC-MS检测条件下会高温分解并释放出苯酚,且热降解程度随着进样口温度的升高而显著增强。用GC-MS法检测含有水杨酸的化妆品时,会得到苯酚含量偏高或假阳性的检测结果。     

GC-MS 法分析生物柴油中脂肪酸甲酯成分的研究

通过利用不同气相色谱-质谱条件对生物柴油中的脂肪酸甲酯成分的分析研究,优选一个 GC-MS 条件,选用PEG-20M的色谱柱,柱温用 150℃ 恒温,进样量为 0.2 μL,分析时间仅用了 12 min,能很好地分离和鉴定生物柴油中主要的10个脂肪酸甲酯,该方法可用于不同植物油制备的生物柴油样品中的脂肪酸甲酯成分的 GC-MS 分析。     

HAPSITE便携式气质谱联用仪使用及维护

介绍了HAPSITE便携式气质谱联用仪在环境污染事故应急监测与处置工作中的作用,并根据日常使用和维护情况,总结了便携式气质谱联用仪性能特点,为相关单位对HAPSITE便携式气质谱联用仪的使用和维护,提供了技术支持。     

气-质联用法快速定性17种农药有效成分

建立了杀虫剂农药中17种可能添加的未经登记农药成分的筛选方法。可疑成分首先通过气相色谱法保留时间进行初筛定性,再经过气相色谱质谱联用仪进行质谱解析确证。同时分析了影响保留时间的主要因子及提高定性准确性的方法,通过选择合适的定性碎片降低相互干扰。为管理部门监管农药生产企业擅自添加未经登记成分提供技术支持。     

Analysis of autoxidized fats by gas chromatography-mass spectrometry: I. Methyl oleate

A structural investigation of autoxidation products of methyl oleate was carried out by gas chromatography-mass spectrometry (GC-MS) of trimethylsilyl (TMS) ether derivatives. GC-MS using computer plots of selected masses afforded structural assignments of GC peaks due to incompletely resolved mixtures. This method provided evidence of epoxy and keto esters which are not completely separated from the main components consisting of the TMS derivatives of the allylic hydroxy esters. Use of an MS-computer system also showed that the hydroxyoctadecanoate TMS ethers were partially separated by GC. The use of synthetic hydroxyoctadecanoates for the first time enabled us to demonstrate the quantitative reliability of a GC-MS computer summation approach to analyze the isomeric composition of oleate hydroperoxides (as the saturated TMS ether derivatives). Consistently higher concentrations were found of the 8- and 11-hydroperoxides than of the 9- and 10-hydroperoxides. Minor products of autoxidation identified by GC-MS include allylic enones, isomeric epoxyoctadecanoates, dihydroxyctadecenoates, and dihydroxyoctadecanoates. Presented at the AOCS Meeting, Chicago, September 1976.     

乳及乳制品中三聚氰胺的检测方法

参照国家质量监督检验检疫总局2008年9月发布的关于乳及乳制品中三聚氰胺的检测标准,介绍国家标准采用的方法的原理。这些方法主要是高效液相色谱、高效液相色谱串级质谱联用法、气相色谱质谱联用法、气相色谱串级质谱联用法。