Sampling process stream

Sampling Process Streams. The most critical step in testing process-stream emulsions is to procure a representative sample from the total produced fluids. Test results will otherwise be meaningless. A good sample therefore must be (2) ... 

The variety of AES techniques requires careful evaluation for selecting the proper approach to an analytical problem. Table 4 only suggests the various characteristics. More detailed treatment of detection limits must include consideration of spectral interferences (191). AES is the primary technique for metals analysis in ferrous and other alloys geological, environmental, and biological samples water analysis and process streams (192). 

Lovelace, B. G. 1979. Safe Sampling of Liquid Process Streams. Chemical Engineering Progress [Nov]. Also published in Vol. 13, C.E.P. Technical Manual. 

Continuous and detailed knowledge of process conditions is necessary for the control and optimization of bioprocessing operations. Because of containment and contamination problems, this knowledge must often be obtained without sampling the process stream. At present, conditions such as temperatme, pressure, and acidity (pH) can be measured rapidly and accurately. It is more difficult to monitor the concentrations of the chemical species in the reaction medium, to say nothing of monitoring the cell density and intracellular concentrations of hundreds of compounds. 

Material balance or weight distribution sheets the laboratory process flow diagrams with material balance or weight distribution sheets for each test system sample are summarized from the raw data process data records. Material balance refers to the balance of a particular component of the food, usually solids, throughout a process. If moisture or total solids are not analyzed for each process stream and only the weights of each process stream are recorded, then the term weight distribution is more properly used. 

In this article, sampling methods for sediments of both paddy field and adjacent water bodies, and also for water from paddy surface and drainage sources, streams, and other bodies, are described. Proper sample processing, residue analysis, and mathematical models of dissipation patterns are also overviewed. 

Drawing samples at certain points of the process, taking them to a laboratory and measuring the shear viscosity over a range of shear rates with a conventional rheometer has been the main method of monitoring the viscosity of process streams. This method is labor and time intensive and in many systems laboratory... 

SPME-IR has been applied to VOCs in soil samples [547], Industrial applications to in-process streams can well be envisaged. SPME has not yet extensively been explored for polymers, but the determination of residual volatiles, semi-volatiles and degradation products in polymers has been reported [548]. It is equally well possible to use SPME for plasticiser analysis in various matrices (water, milk, blood, processed food, etc.). 

The above system of directly sensing a process stream without more is often not sufficiently accurate for process control so, robot titration is preferred in that case by means of for instance the microcomputerized (64K) Titro-Analyzer ADI 2015 (see Fig. 5.28) or its more flexible type ADI 2020 (handling even four sample streams) recently developed by Applikon Dependable Instruments20. These analyzers take a sample directly from process line(s), size it, run the complete analysis and transmit the calculated result(s) to process operation (or control) they allow for a wide range of analyses (potentiometric, amperometric and colorimetric) by means of titrations to a fixed end-point or to a full curve with either single or multiple equivalent points direct measurements with or without (standard) addition of auxiliary reagents can be presented in any units (pH, mV, temperature, etc.) required. 

Petty et al. [293] used flow injection sample processing with fluorescence detection for the determination of total primary amines in sea water. The effects of carrier stream flow rate and dispersion tube length on sensitivity and sampling rates were studied. Relative selective responses of several amino acids and other primary amines were determined using two dispersion tube lengths. Linear calibration curves were obtained over the ranges 0-10 6 M and... 

Chemical analysis finds important applications in the quality control of industrial processes. In an ideal situation a continuous analysis of the process stream is made and some aspects of this are discussed in Chapter 12. However, such continuous analysis is by no means always possible, and it is common to find a process being monitored by the analysis of separate samples taken at regular intervals. The analytical data thus obtained need to be capable of quick and simple interpretation, so that rapid warning is available if a process is going out of control and effective corrective action can be taken. 

It is obvious that the simpler a method of analysis, the easier it will be to automate. Non-destructive methods which involve a minimum of sample treatment are the most attractive. X-ray fluorescence, for example, has been successfully applied to the continuous monitoring and control of process streams. However, the scope of automated analysis is wide and methods have been designed with a basis in nonspecific properties (pH, conductance, viscosity, density) as well as those characteristic of the che-... 

Flow injection analysis is a fast-developing technique with many potentialities. Particular attractions are the relative simplicity of operation and automation, together with sample throughputs which may exceed 100 per hour. Thus routine monitoring of process streams and pollution control are obvious areas for application. 

Newer techniques for measuring the refractive index allow for instantaneous, real-time measurement in process streams, or alternatively, a special continuous-flow sample well can be installed on bench top instruments. Small, pocket-sized refractometers also make held measurement very simple and reliable. Fiber optic sensors find uses in biomedical applications. 

This measurement is actually one of pH. The principle involves the measurement of the pH of a bicarbonate solution separated from the sample by a CCh-permeable membrane. CO2 diffuses in (or out) and changes the bicarbonate solution pH in proportion to the pCCh in the sample. This method has all the drawbacks of pH measurement with a glass electrode. The problems associated with this method perhaps explain why it is not widely used in biochemical engineering laboratories and process streams despite its considerable metabolic significance 5 ... 

Yeung et al. addressed the question of whether or not pull samples gave as good equations as samples measured on-line.47 The so-called add-back and process-stream samples were compared for statistical robustness in the equations they produced and their performance in predicting values in an on-line reaction. Materials such as biomass (optical density), protein, and RNA were measured by both techniques. 

It was found that fewer PLS factors were needed for process stream samples to yield a decent model. The correlation coefficients were stronger and the SEPs lower in every case. One example is protein add-back r2 = 0.891 using four PLS factors, whereas the process-stream samples enabled a three-factor PLS model to be generated with an r2 = 0.915. The respective SEP for each model was add-back = 4.351 process = 2.343. This paper seems to confirm the idea that samples taken during a process are more representative of that process. 

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