Batch process monitoring using on-line MIR spectroscopy

Many high quality products are produced in a batch wise manner. One of the characteristics of a batch process is the recipe driven nature. By repeating the recipe in an identical manner a desired end-product is obtained. However, in spite of repeating the recipe in an identical manner, process differences occur. These differences can be caused by a change of feed stock supplier or impurities in the process. Because of this, differences might occur in the end-product quality or unsafe process situations arise. Therefore, the need to monitor an industrial batch process exists. An industrial process is usually monitored by process measurements such as pressures and temperatures. Nowadays, due to technical developments, spectroscopy is more and more used for process monitoring. Spectroscopic measurements have the advantage of giving a direct chemical insight in the process. Multivariate statistical process control (MSPC) is a statistical way of monitoring the behaviour of a process. Combining spectroscopic measurements with MSPC will notice process perturbations or process deviations from normal operating conditions in a very simple manner. In the following an application is given of batch process monitoring. It is shown how a calibration model is developed and used with the principles of MSPC. Statistical control charts are developed and used to detect batches with a process upset.     

化学计量学在过程分析中的应用及进展

评述了化学计量学方法在生产过程分析中各个方面 ,如过程优化、过程模拟、仪器及仪器校正、过程监测等方面的应用 ,并展望了化学计量学在过程分析中的应用前景     

Unusual relaxation process in polybutadiene: Resolving the controversy

We report the observation of an unusual relaxation process in depolarized light scattering spectra of polybutadiene (PBD) with two different vinyl contents. The process showed up in the gigahertz frequency range with relatively mild temperature dependence and was similar to a secondary relaxation process. The most surprising observation was that the process exists even at high temperatures and does not merge with the segmental relaxation up to a temperature of 400 K (T > 2T_g). Possible mechanisms of this particular relaxation in PBD are discussed. The process is compared to the so‐called E process, double‐bond hopping process, and dielectric β process. We emphasize that this process differs from the dielectric β process, is unique for 1,4‐PBD, and has not been observed in other polymers. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 994–999, 2004     

Optimization of Saccharification and Fermentation Process in Bioethanol Production from Oil Palm Fronds

Oil Palm Frond (OPF) is one of lignocellulosic biomass, which can be utilized as raw material for bioethanol production. Bioethanol is produced as alternative energy to substitute gasoline. There are four steps in bioethanol production from OPF, i.e pretreatement, saccharification, fermentation and purification process. In this study, optimization of saccharification and fermentation process for OPF was investigated. Two methods and the variations of enzyme concentration were carried out in the saccharification and fermentation process. Separate hydrolysis and fermentation process (SHF) and simultaneous saccharification and fermentation process (SSF) were conducted to produce ethanol optimally. Variations of enzyme concentration used in this process were 10, 20, 30 and 40 FPU/g substrate. The result shows that the highest ethanol concentration can be obtained in SSF process with 30 FPU/g substrate of enzyme concentration. The process produced 59.20 g/L ethanol (95.95% yield ethanol) at 96 h of SSF process.     

稀土萃取分离过程自动控制研究现状及发展趋势

在简要描述稀土萃取分离生产过程的基础上,综述了目前国内外稀土萃取分离过程中稀土元素成分在线检测的方法、装置及其应用现状;稀土串级萃取分离生产过程的计算机流程模拟以及稀土萃取生产过程的自动控制方法、技术及其应用现状.指出了稀土元素组分含量的软测量方法,以综合生产指标为目标的稀土萃取分离生产过程优化控制方法以及由生产过程管理系统和过程控制系统两层结构组成的稀土萃取分离生产过程综合自动化系统已成为稀土萃取分离生产过程自动化未来发展的方向.     

氟碳铈矿提取稀土的绿色化学进展

氟碳铈矿是稀土工业的重要原材料，目前从氟碳铈矿提取稀土主要采用酸法工艺，该工艺虽然稀土回收高，但流程长，试剂消耗长，成本较高，同时酸法产生ＨＦ及废酸碱污染环境。因此寻找低成本，低污染的绿色化学处理工艺是近几十年中人们一直努力的方向。本文系统介绍了氟碳铈矿分解工艺的发展，并着重介绍邓氯化铵法提取氟碳铈矿稀土的的新工艺。该工艺采用盐类分解并氯化氟碳铈矿，直接用水浸取回收稀土，不引入酸和碱，提高了反应选择性，减轻了稀土在稀土杂质分负荷，降低了化工材料消耗，简化了工艺，提高了回收率，是符合绿色化学要求的工艺。     

煤化工工艺技术评述与展望Ⅳ．煤间接液化技术

评述了国内外煤间接液化合成液体燃料开发趋势和工业化状况,从催化剂研制,F－T合成反应器开发,合成油工艺路线,工艺软件开发,工艺集成优化和技术经济分析等方面进行了讨论,指出发展洁净高效煤基合成液体燃料工业过程是解决我国燃油短缺的根本途径,并对我国煤制油工业化开发工作和示范厂建立提出一些建议和展望。     

改进层次分析法在污水处理工艺选择中的应用

采用传统的层次分析方法(Analytic Hierarchy Process,AHP)进行污水生化处理工艺的选择时,其科学性和可操作性均较低,而改进的AHP法采取三标度法,判定矩阵较易构造,且无需进行一致性检验。本研究采用改进的AHP法,建立了4层10指标4方案的污水处理工艺综合评价体系,分别对MBR、A~2/O、A/O和氧化沟工艺的经济效益、环境影响及技术性能进行分析。结果表明,MBR、A~2/O、A/O和氧化沟工艺的评价体系公式计算结果分别为0.3137、0.3379、0.2085和0.1552。因此,在我国东北地区,综合考虑经济效益、环境影响及技术性能,A~2/O工艺为最适宜的生化处理工艺,其次是MBR工艺和A/O工艺,而氧化沟工艺为最不推荐的工艺。改进的AHP法可对现有污水处理工艺的经济效益、环境影响及技术性能进行直观的评价,从而为现有工艺的运行管理以及新工艺的设计提供理论及实践依据。     

Monitoring of an industrial process by multivariate control charts based on principal component analysis

The control and monitoring of an industrial process is performed in this paper by the multivariate control charts. The process analysed consists of the bottling of the entire production of 1999 of the sparkling wine "Asti Spumante". This process is characterised by a great number of variables that can be treated with multivariate techniques. The monitoring of the process performed with classical Shewhart charts is very dangerous because they do not take into account the presence of functional relationships between the variables. The industrial process was firstly analysed by multivariate control charts based on Principal Component Analysis. This approach allowed the identification of problems in the process and of their causes. Successively, the SMART Charts (Simultaneous Scores Monitoring And Residual Tracking) were built in order to study the process in its whole. In spite of the successful identification of the presence of problems in the monitored process, the Smart chart did not allow an easy identification of the special causes of variation which casued the problems themselves.     

恒温过程的热量传递

目前,基于物化教材上对"恒温过程"和"热"的定义,初学者在理解恒温过程的热量传递时往往会产生很大困惑。对概念的孤立和片面理解是造成该结果的根本原因。本文借助数学上的极限思想,以理想气体的恒温可逆膨胀过程为例,对该过程的能量传递做出详细剖析,以消除物理化学初学者在入门期的学习障碍。     

Infrared multiphoton decomposition and the possibilities of laser-based heavy water processes

The selective multiphoton decomposition (MPD) process has the potential to provide a stand-alone heavy water process which is competitive with conventional processes. Twelve criteria are discussed for selecting a working molecule to give a process economically competitive with the Girdler-Sulphide process. The dependence of the MPD process on interacting parameters such as laser fluence, intensity and bandwidth as well as collisional effects are discussed. Finally, several potential working molecules are reviewed.     

Deacidification of citric acid solutions by electrodialysis

Electrodialysis is a useful process to deacidify citrus juices. Besides the known allanion exchange membrane process, two alternative electrodialysis processes were investigated: a three-stream process using cation and anion exchange membranes and a twostream process with alternately arranged bipolar and anion exchange membranes. The results taken from a laboratory electrodialysis cell show, that according to current efficiency, consumption of sodium hydroxide and by-production of sodium citrate or citric acid the alternative processes are favourable, especially the process using bipolar membranes.     

Identification of nitrate ester explosives by liquid chromatography-electrospray ionization and atmospheric pressure chemical ionization mass spectrometry

A new continuous chromatographic process (VARICOL) has been presented recently. The basic principle of the new VARICOL process consists of an asynchronous shift of the inlet/outlet lines in a multi-column system on a recycle loop. This process has been used to perform the separation of the optical isomers of the SB-553261 racemate. In this paper, we illustrate that for this specific separation, the VARICOL process is more efficient than the well-known SMB process.     

Using computer simulation to assist in the robustness analysis of an ion-exchange chromatography step

This paper presents a methodology to gain process knowledge and assist in the robustness analysis of an ion-exchange step in a protein purification process using a model-based approach. Factorial experimental design is common practice in industry today to obtain robustness characterization of unit operations with respect to variations in process parameters. This work aims at providing a better insight into what process variations affect quality and to further reduce the experimental work to the regions of process variation that are of most interest. This methodology also greatly increases the ability to predict process performance and promotes process understanding. The model calibration part of the methodology involves three consecutive steps to calibrate a steric mass action (SMA) ion-exchange chromatography model. Firstly, a number of gradient elution experiments are performed. Secondly, experimental breakthrough curves have to be generated for the proteins if the adsorption capacity of the medium for each component is not known. Thirdly, a multi-component loading experiment is performed to calibrate the multi-component effects that cannot be determined from the single-component experiments. The separation process studied in this work is the separation of polyclonal IgG from a mixture containing IgG, myoglobin and BSA. The calibrated model is used to simulate six process variations in a full factorial experiment. The results of the simulations provide information about the importance of the different process variations and the simulations are also used to determine the crucial points for the process parameter variations. The methodology can be used to assist in the robustness analysis normally performed in the pharmaceutical industry today as it is able to predict the impact on process performance resulting from variations in salt concentration, column load, protein concentration and flow rate.     

Cationic membranes for phenols production

Ionic Substitution by Electrodialysis is a good alternative to the industrial conversion of sodium salts of phenols into undissociated phenols, conventionally performed through acidification by strong acids. The acidification through electromembranes combines the possibility to achieve high conversion values with the advantage of keeping the process stream separated from the acid stream. The process is performed through cationic membranes; conversion can be obtained also in the absence of electric current, even if slightly better performances can be achieved by applying an electric field. Process feasibility as well as membrane resistance is tested, for the case of model solutions reproducing the main features of the real process streams. Maximum conversion and process rate are greatly affected by the ratio between protons in the acid solution and sodium ions in the process solution. Phenol losses into the acid stream and chloride contamination of the process stream can be reduced by working with diluted process and acid streams.     

Micronization of tolbutamide using rapid expansion of supercritical solution with solid co-solvent (RESS-SC) process

Micronization of a sulfonylurea antidiabetic agent, tolbutamide, using rapid expansion of supercritical solution with solid co-solvent (RESS-SC) process was investigated in this study. Menthol was selected as the solid co-solvent in the RESS-SC process owing to its high vapor pressure and ease of removal by sublimation. The tolbutamide particles were micronized successfully from its original mean size of 89.4 ??m to the smallest mean size of 2.1 ??m through the RESS-SC process. The use of solid co-solvent in this process enhanced the saturated solubility of tolbutamide in supercritical carbon dioxide and inhibited the particle growth during pressure expansion after the nozzle. In addition, polymorph conversion from form I to form II after the RESS-SC process was confirmed by XRD and DSC analyses. Measurements of the dissolution rate profiles before and after the RESS-SC process were also investigated. It is shown that the micronized tolbutamide by the RESS-SC process had novelty in dissolution behavior compared to that of the original compound. Its dissolution rate was enhanced by 8.8 times after the RESS-SC process.     

Release from or through a wax matrix system. VI. Analysis and prediction of the entire release process of the wax matrix tablet

Analysis of the entire release process of the wax matrix tablet was examined. Wax matrix tablet was prepared from a physical mixture of drug and wax powder to obtain basic or clear release properties. The release process began to deviate from Higuchi equation when the released amount reached at around the half of the initial drug amount. Simulated release amount increase infinitely when the Higuchi equation was applied. Then, the Higuchi equation was modified to estimate the release process of the wax matrix tablet. The modified Higuchi equation was named as the H-my equation. Release process was well treated by the H-my equation. Release process simulated by the H-my equation fitted well with the measured entire release process. Also, release properties from and through wax matrix well coincident each other. Furthermore, it is possible to predict an optional release process when the amount of matrix and composition of matrix system were defined.     

Broadband dielectric study of the glass transition in poly(ethyleneglycol)-water mixture

We performed broadband dielectric measurements of a polyethyleneglycol-water mixture in the frequency range between 10 GHz and 1 microHz and the temperature range between 300 and 133 K. One relaxation process is observed throughout the whole temperature range. The temperature dependence of the relaxation time clearly obeys the Vogel-Fulcher law above 183 K, and the Arrhenius law below 183 K. This observed relaxation process is the secondary process, and the primary process related to the glass transition is masked by the low-frequency ionic contribution below 183 K. The glass transition concerned with the masked primary process leads to the Vogel-Fulcher to Arrhenius transition of the secondary process.     

Analysis of Volatile Components of Jasmine and Jasmine Tea during Scenting Process

Jasmine tea is widely loved by the public because of its unique and pleasant aroma and taste. The new scenting process is different from the traditional scenting process, because the new scenting process has a thin pile height to reduce the high temperature and prolong the scenting time. We qualified and quantified volatiles in jasmine and jasmine tea during the scenting process by gas chromatography-mass spectrometry (GC-MS) with a headspace solid-phase microextraction (HS-SPME). There were 71 and 78 effective volatiles in jasmine and jasmine tea, respectively, including 24 terpenes, 9 alcohols, 24 esters, 6 hydrocarbons, 1 ketone, 3 aldehydes, 2 nitrogen compounds, and 2 oxygen-containing compounds in jasmine; 29 terpenes, 6 alcohols, 28 esters, 8 nitrogen compounds, 1 aldehyde, and 6 other compounds in jasmine tea. The amounts of terpenes, esters, alcohols, nitrogen compounds, and hydrocarbons in jasmine and tea rose and then fell. The amount of oxygenated compounds of tea in the new scenting process first rose and then fell, while it showed a continuous upward trend during the traditional process. The amount of volatiles in jasmine and tea produced by the new scenting process were higher than that of the traditional scenting process at the same time. This study indicated that jasmine tea produced by the new scenting process had better volatile quality, which can provide proof for the new scenting process.