航煤、柴油色谱模拟蒸馏的应用

介绍了采用气相色谱模拟蒸馏的原理快速测定航煤、柴油的馏程的方法。使用一条具有一定分离度的非极性毛细管色谱柱,将样品通过可程序升温进样口进入色谱柱,在线性程序升温条件下将样品按沸点次序分离,模拟经典实沸点蒸馏测定出馏程;并通过经典手工馏程分析数据,对每一类样品的结果进行修正,建立相对应的样品类型。试验表明,采用气相色谱模拟蒸馏可在8 min内准确、简便地测定出航煤和柴油的馏程。     

新型多组分连续制备色谱系统--阵列式柱色谱

本文介绍了一种新型多组分连续制备色谱系统———阵列式柱色谱。该系统是在综合了模拟移动床色谱和旋转环状色谱的工作原理的基础上开发出来的 ,主要由控制部分、流体输送部分、分离部分、检测部分和收集部分所组成。在分离部分中 ,本系统用色谱柱阵列代替了旋转环状色谱的环形填料层 ,即避免了溶质横向扩散和动密封问题 ,又可以根据实际生产需要增减色谱柱数目 ;在收集部分中 ,使用了专门为本系统设计的收集器实现了所有色谱柱流出液的集中收集 ;本系统采用将试验和生产一体化的设计 ,通过将单柱模式下的使用在线检测得出的优化分离条件应用到多柱模式中 ,实现了系统的柔性设计 ,降低了设备成本 ;用户可以通过使用装有系统控制软件的上位机与系统进行实时交互 ,大大提高了系统运行自动化程度 ,简化了操作。具有上述优点的本系统必将有着广泛的应用前景     

在线色谱分析仪柱箱温度控制系统的改造

色谱柱柱箱是在线色谱分析仪的关键部件,柱箱温度的变化直接影响在线色谱分析仪分析数据的准确性,因此,对色谱柱柱箱温度控制系统进行改造,以提高在线色谱分析仪的整体性能。     

模拟蒸馏测定常压直馏柴油馏程研究

利用气相色谱,使用微径毛细管色谱柱,自动进样器,对常压直馏柴油的馏程进行快速测定,并对其方法的重复性及模拟蒸馏中收率点的选取进行了研究和分析。结果表明:应用快速模拟蒸馏技术测定常压直馏柴油的馏程是可行的。利用模型计算值与恩氏蒸馏测定值之间的测量差异获得模型校正参数,对原始模型进行校正,校正模型已成功地应用于常压直馏柴油的恩氏蒸馏馏程预测。     

气相色谱模拟蒸馏在加氢尾油馏程分析中的应用

研究了气相色谱模拟蒸馏测定加氢尾油沸程分布的方法,通过使用正构烷烃校正样进行沸点一保留时间校正分析,用标准参考样进行准确性检查。从而测得样品的百分收率一沸点的馏程数据。同时,考察并探讨了沸点一保留时间校正、基线补偿、色谱柱性能、二硫化碳溶荆及样品洗提时间等主要因素对模拟蒸馏结果的影响。     

基于模拟蒸馏技术的油品质量在线分析系统

介绍了一种自主研发的基于气相色谱模拟蒸馏技术的新型油品质量在线分析系统.重点讨论在线分析系统的构成、在线色谱模拟蒸馏分析仪的结构和数据处理系统的设计.利用该在线分析系统,可共享在线色谱模拟蒸馏分析仪的硬件平台,实现油品馏程、闪点等多种质量参数的在线检测.该系统已经成功应用于炼油厂常减压装置.     

有机硅偶联剂填充气相色谱测定方法的研究

采用自制填充色谱柱，热导检测器，建立了有机硅偶联剂填充气相色谱测定方法，解决了毛细管色谱分析中存在的氢焰喷口易堵塞、对毛细柱的损害大及结果重复性差等问题。     

气相色谱馏程关联方法及工业应用

基于ASTM D2887与ASTM D86测试标准的馏程关联方法是气相色谱模拟蒸馏工程应用的一个重要技术研究方向,关联模型的泛化能力和鲁棒性是评价模型性能的主要指标。根据色谱模拟蒸馏技术的恩氏蒸馏馏程测定方法,以ASTM方法模型为基础,利用模型计算值与实验值之间的误差获得模型校正参数,对原始模型进行校正,提出了基于加权优化均方差及方差的关联建模方法。通过理论分析、数学计算及工程应用,验证该方法具有很好的鲁棒性和泛化性。工程应用结果表明：提出的色谱模拟蒸馏与恩氏蒸馏数据的关联方法,不仅能扩展模拟蒸馏的使用范围,而且为快速测定油品馏程提供一种可靠的分析手段。     

色谱理论数学模型的计算机模拟实现

根据色谱理论,建立了板高的数学模型,并对模型中的参数进行了初步的确定。通过使用面向对象语言对色谱柱进行编程,模拟绘制了多组分情况下的色谱图。通过色谱图分析,模拟柱温、柱长等参数的变化对色谱的影响与实际分析中色谱图改变是一致的。可以为色谱分析人员确定和优化实际样品的分离分析条件提供有效的参考意见。     

气相色谱固定相的演变

简要综述了半个世纪以来气相色谱固定相的发展,在气相色谱发展的初期主要是低分子化合物和工业用高聚物,主要用于填充柱气相色谱,有上千种固定液。到上世纪80年代以后毛细管柱气相色谱起主导作用,固定液数量减少、质量提高,最常用的有五六种。到上世纪90年代以后固定相的研究以手性固定相和提高常规固定相的性能为主。进入21世纪,各个制备色谱柱的公司不断推出高性能、低流失、重复性好和专用型毛细管柱色谱柱,以适应研究和实际需要。     

基于组态软件和PLC的反向在线色谱在PVC脱吸性能研究方面的应用

为了对PVC脱吸性能进行评价,系统用PVC树脂填充色谱柱,VCM作为探针分子,N2做载气,设计了一套基于组态软件IFIX和PLC的反向在线色谱控制系统。整个监控系统由上位计算机、Siemens S7-200 CN系列PLC、气相色谱、通讯模块和现场执行单元构成,并以VB6.0作为开发语言对生产过程进行控制。经过测试,系统运行稳定、安全可靠,达到了设计目标。     

A self tuning controller for multicomponent batch distillation with soft sensor inference based on a neural network

Multicomponent batch distillation is an operation difficult to control not only for its nonlinear and transient behaviour, but because the product quality cannot be measured rapidly and with reliability. In the present work, a computational system for direct digital control is developed for a pilot plant batch distillation column. The development of a self tuning regulator and a soft sensor of composition based on a neural network is described. Top and reboiler temperature measurements are the basis for the on-line composition inference. The computational system was experimentally tested in a computer operated pilot column. It could be seen that the neural network soft sensor is a feasible and a reliable tool to solve on-line operational problems of the control engineering systems. The developed control system permits to operate the batch distillation column efficiently and is easy to be implemented and operated.     

Design and control of butyl acrylate reactive distillation column system

In this study, the design and control of a reactive distillation column system for the production of butyl acrylate has been investigated. The proposed design is quite simple including only one reactive distillation column and an overhead decanter. The optimal design is selected based on the minimization of total annual cost (TAC) for the overall system. At this optimized flowsheet condition, output multiplicity was found with reboiler duty or feed ratio as the bifurcation parameter. The highest purity stable steady state was selected as the base case condition for the control study. The overall control of this system can be achieved with no on-line composition measurements. Simple single-point tray temperature control loop is designed to infer final product purity. From results of dynamic simulation, the proposed control strategy performs very well in rejecting various disturbances while maintaining butyl acrylate product at high purity. One of the important finding in this paper is that it is better to operate this reactive distillation column not at the exact feed stoichiometric balance point for better operability reason. The control performances of the proposed operating point and the operating condition right at the exact stoichiometric balance point will be compared.     

基于无线HART的智能仪表在线监控系统

为了充分利用传统HART仪表,提高控制系统的可靠性,减少现场仪表的维护量并降低维护费用,提出了一种基于无线HART协议的智能仪表在线监控系统,给出了系统的软、硬件设计思想和实现方法.     

换热器设计中常见问题分析

管壳式换热器是当前工业换热设备中的一种主要型式,其设计的质量直接决定了它在工业换热中的性能表现。对管壳式换热器的设计过程进行了跟踪分析,寻求可能对管壳式换热器的设计质量造成负面影响的主要问题,并且找到相应的解决途径。     

Gas liquid chromatographic analysis of hydroxy fatty acids,as their trimethylsilyl ether derivatives

A quantitative method is described for the rapid gas liquid chromatographic analysis of mono- and polyhydroxystearates as their trimethylsilyl (TMS) ether derivatives. The TMS derivatives of the hydroxy esters are formed rapidly and quantitatively at room temp. The retention times of ricinoleic acid as the methyl ester, acetylated derivative and the TMS derivative are compared. Purified diastereoisomers of di-, triand tetrahydroxystearates and their mixtures were analyzed on three different columns. Gas liquid chromatographic analysis of methyl mono-, di-, tri- and tetrahydroxysteartes were shown to give quantitative results as TMS derivatives. Analyses were carried out on a diethylene glycol succinate polyester (DEGS) packed column and on large-bore capillary columns of DEGS and Apiezon L. The elution order of the TMS derivatives of the hydroxy esters from the DEGS largebore capillary column was not the same as that obtained from the DEGS packed column. The unusual elution pattern of the large-bore capillary column is discussed. Presented at the AOCS Meeting in New Orleans, 1964.     

高纯度丙烯中烃类杂质分析方法的比较与优化

从柱温控制的角度对分析标准推荐的实验条件进行了优化和改进,从而保证了正常操作状态下各组分分析结果的准确度全部符合分析标准的规定;色谱运行时间由原来的40 min减少到20 min,而且达到了丙烯中烃类杂质组分完全分离的色谱效果,实现了一次进样分析。色谱仪的占用由原来的3台减少到1台,降低了分析成本。     

Variable measurement structures for the control of a tubular reactor

The feasibility of the variable measurements structure is investigated within the framework of controlling a tubular chemical reactor. An on-line sequential analysis of the temperature measurements along the length of the reactor, allows a fast and time-adaptive selection of the best measurements to be used in a low order, simple and robust control scheme. The approach has been developed for both static and dynamic cases. It is based on a recursive computation of the state estimate errors. Its theoretical and computational simplicity makes it attractive for on-line implementation. The procedure has been applied for the adaptive tubular reactor under pseudo-steady state and dynamic conditions with very encouraging results.     

Unsteady-State Model for Continuous Moving-Bed Chromatography

Abstract

Mathematical equations have been formulated to predict the longitudinal concentration distribution in the case of instantaneous behavior of a continuous chromatographic system. Partial differential equations are initially obtained from mass balance on the differential element of column height. The formulated equations are solved by Lap lace transformation and the contour integration method. Two equations are obtained, one for the column section above the feed point and the second for the column section below the feed. Both of these equations give the concentration distribution along the appropriate section of the column. The model predicts the instantaneous and steady-state behavior of the continuous moving-bed chromatographic system. The model can also be used as a tool for the design of new continuous chromatographic columns.     

A modification of the thiobarbituric acid reaction

A simple modification of the thiobarbituric acid reaction, which removes nonspecific chromogenic reaction products, involves incubation at room temperature for 16–20 hr and a column chromatographic step. The chromogen-concentrating capacity of the latter step is useful for determination of low concentrations of thiobarbituric acid-reactive materials in biological preparations.