Batch process monitoring

In monitoring and evaluating the hazards of toxic substances, impurities are an area of concern. Industrial chemicals are likely to be a major source of mutagenic impurities. The Salmonella test can be used in the design of industrial syntheses and as a batch process monitor to minimize the introduction of mutagenic impurities. 

A short description of monitoring continuous processes for deviating behavior will be given, because some parts of batch process monitoring are taken from that area. Monitoring batch processes is discussed in detail as three-way analysis is heavily involved in that area. 

Some other applications in batch process monitoring... 

In the area of polymerization processes, case studies of batch process monitoring based on the Nomikos and MacGregor scheme were reported. In an emulsion batch polymerization, 46 batches were available each having 106 measurements taken during the batch run of 20... 

In this work, we describe an approach to integrate multivariate statistical process monitoring and online HAZOP analysis for abnormal event management of batch processes. The framework consists of three main parts process monitoring and fault detection, automated online HAZOP analysis module and a coordinator. Multiway PCA is used for batch process monitoring and fault detection. When abnormal event is detected, signal-to-symbol transformation technique based on variable contribution is used to transfer quantitative sensor readings to qualitative states. Online HAZOP analysis is based on PHASuite, an automated HAZOP analysis tool, to identify the potential causes, adverse consequences and potential operator options for the identified abnormal event. 

Multiway Principal Component Analysis (PCA) for Batch Process Monitoring... 

Basic process control system (BPCS) loops are needed to control operating parameters like reactor temperature and pressure. This involves monitoring and manipulation of process variables. The batch process, however, is discontinuous. This adds a new dimension to batch control because of frequent start-ups and shutdowns. During these transient states, control-tuning parameters such as controller gain may have to be adjusted for optimum dynamic response. 

Batch processes may require more monitoring in order to take supervisory action (e.g., put the system on hold if a particular manual valve is not closed). 

Selecting people with the appropriate capabilities and skills will result in fewer errors being made. Operator selection is important because the operator is a participant in batch processes whereas in continuous plants he/she performs more of a monitoring role. The most experienced and well qualified operators should be assigned to the more hazardous processes. Pair new operators (even experienced operators who are new to the process) with operators experienced in the process. 

Consider a process worker monitoring a control panel in a batch processing plant. The worker is executing a series of routine operations such as opening and closing valves and turning on agitators and heaters. 

Use semi-batch processes for exothermic reactions and monitor the consumption rate of the limiting reactant. 

Gurden et al. studied the monitoring of batch processes using spectroscopy. As a case study, they followed a pseudo first-order biochemical reaction with an intermediate using UV-vis spectroscopy. Following statistical process monitoring, process disturbances could be detected in a series of batches. 

The challenge of monitoring batch processes for deviations was addressed by Gabrielsson et aP" (also taken up by Wong et al. °) with the hydrogenation of nitrobenzene to aniline as a model reaction. The study followed a factorial design of experiments. Process deviations could only be detected when the UV spectroscopic data set and the process data set were used in a combined manner, not seperately. 

C. Cannizzaro, M. Rhiel, 1. Marison and U. von Stockar, On-line monitoring of Phaffia rhodozyma fed-batch process with in situ dispersive Raman spectroscopy, Biotechnol. Bioeng., 83, 668-680 (2003). 

Cost reductions usually arise out of improvements to the process control for both continuous and batch processes. Process analyzers enable chemical composition to be monitored essentially in real time. This in turn allows control of the process to be improved by shortening start-up and transition times (for continuous processes) or batch cycle times (for batch processes). This is accomplished by improving the ability to respond to process disturbances, by enabling process oscillations to be detected and corrected, and by reducing product variability. Real-time monitoring of chemical composition in a process allows a manufacturing plant to ... 

An example of CQV of the batch cultivation of a vaccine has been demonstrated, where univariate (temperature, dissolved oxygen, pH) as well as spectroscopic tools were used to develop process models. The measurements were used for a consistency analysis of the batch process, providing better process understanding which includes the understanding of the variations in the data. MSPC analysis of four batches of data was performed to monitor the batch trajectories, and indicated that one batch had a deviation in the pH. From the MSPC information, combined with calibration models for the composition of the process based on NIR spectral data, improved monitoring and control systems can be developed for the process, consistent with concept of CQV. The data from the univariate sensors and NIR were also fused for a global analysis of the process with a model comprised of all the measurements. 

The lead time, for incorporation of enzymes as an adjunct in whatever form into commercial food processes, appears to be far longer than equivalent innovation lead times m non-food, or even pharmaceutical processes. The exception to this finding is that there are enzymes which play an important role in many analytical and quality control procedures in the food industry, without the use of which, for batch or continuous process monitoring, many product lines would not be possible. 

Wang et al. [42,67,68] have developed innovative biological process and sequencing batch reactors (SBR) specifically for removal of volatile organic compounds (VOCs) and surfactants. Related analytical procedures [57-64,71-91] available for process monitoring and control are available in the literature. 

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