Process analysis sampling point

Process specifications will typically be set forth in the process technology package. However, a process hazard analysis (PHA) in preparation for startup may reveal additional useful measurements or sample points. These may be analyses or measurements for the startup period or for the life of the toll. 

Sampling points for analysis should be planned in order to give the whole record of analysis, e.g. in oil production from the well via processing facilities to the export facilities. Correlation with plant parameters such as temperatures, pressures, flow rates and, stream compositions can provide valuable records. Emphasis on chemical analysis should be incorporated in the design of process plant. Automatic analysis systems especially those using ion-sensitive electrodes with recording of data are recommended. 

As a consequence, good, safe, steam-sampling points are required, and automatic, real-time continuous analyzer systems for monitoring of steam and condensate quality are very useful. These requirements usually are not a problem in larger power and process HP boiler plants. Here, each facility tends to have a unique combination of operating conditions and waterside chemistry circumstances that necessitate the provision of a steady stream of reliable operational data, and this can be obtained realistically only from continuous, real-time analysis. 

Since both the direct and phased approaches offer, at least in principle, equal promise for ultimate success (i.e., comprehensiveness and complete characterization), it is worthwhile to examine their relative resource requirements. Several studies were conducted with the objective of comparing the costs of direct and phased (with elimination of low priority streams) sampling and analysis approaches. (2,3] A number of processes were evaluated during these studies and the results for two unit operations — a limestone wet scrubber and full-scale low-Btu coal gasifier — are taken as examples. The scrubber involved seven feed or waste stream sampling sites. The gasifier contained 70 identifiable stream sampling points. The total estimated costs for both processes by both approaches are shown in Table I. 

Sampling strategy is the first step in the analysis process, in which the analyst must make a number of decisions about location of sampling points, method of sampling, and the number and size of the samples. Concerning the former and, according to... 

Product quality is assured through the collection and analysis of samples taken from the process (see Sec. 6 on sampling) to establish the acceptability of the process. The optimal approach to validation considers process parameters and product attributes, as well as their relationship. The link between the defined independently established parameters (either variable or fixed process equipment set points) must be established during the developmental process. The PQ of a pharmaceutical process should demonstrate how conformance to the required... 

Fisher suggested to transform the multivariate observations x to another coordinate system that enhances the separation of the samples belonging to each class tt [74]. Fisher s discriminant analysis (FDA) is optimal in terms of maximizing the separation among the set of classes. Suppose that there is a set of n = ni + U2 + + rig) m-dimensional (number of process variables) samples xi, , x belonging to classes tt, i = 1, , g. The total scatter of data points (St) consists of two types of scatter, within-class scatter Sw and hetween-class scatter Sb- The objective of the transformation proposed by Fisher is to maximize S while minimizing Sw Fisher s approach does not require that the populations have Normal distributions, but it implicitly assumes that the population covariance matrices are equal, because a pooled estimate of the common covariance matrix (S ) is used (Eq. 3.45). 

Technique Total analysis time (min) Throughput Processing of assay points per day Cost per sample (US )... 

Process analysis means analysing samples from a process in real-time as distinct from waiting until the end of the process to take samples for subsequent analysis in a laboratory. In recent years, this has meant the migration of certain analytical testing from the laboratory into production and direct measurement at sampling points during manufacturing. The data obtained are used to control the process itself, and hence the quality of the products made. Process analysis is now a substantial area for use of analytical instruments. 

S-IO C above that of the experiment. The sampling point was 3-5 mm from the solution surface. About 3-5 sec before sampling the stirrer was stopped to avoid splashing of the syringe needle. The proposed technique [39] was tested on the reduction of some alkyl halides with sodium borohydride in dimethylformamide. It was shown that the kinetic curves derived as a result of chemical freezing of samples practically coincided with those obtained by analysis of an equilibrium vapour phase. The technique is recommended for studying processes with a half-time of transformation exceeding lOmin. 

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