Continuous analyzers

The continuous methods combine sample collection and the measurement technique in one automated process. The measurement methods used for continuous analyzers include conductometric, colorimetric, coulometric, and amperometric techniques for the determination of SO2 collected in a liquid medium (7). Other continuous methods utilize physicochemical techniques for detection of SO2 in a gas stream. These include flame photometric detection (described earlier) and fluorescence spectroscopy (8). Instruments based on all of these principles are available which meet standard performance specifications. 

Where-high purity MU is provided for higher pressure WT boiler plant FW, some form of continuous analyzers for measuring treated water pH and conductivity are almost always installed, as are sodium (Na) ion-selective electrodes for detection of sodium leakage. Automatic online silica analyzers also may be installed, but they measure only reactive (ionizable) silica (Si02), not colloidal or total silica, so caution is required where unforeseen silica leakage may present a problem. 

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. 

Specific surface areas of the catalysts used were determined by nitrogen adsorption (77.4 K) employing BET method via Sorptomatic 1900 (Carlo-Erba). X-ray difiraction (XRD) patterns of powdered catalysts were carried out on a Siemens D500 (0 / 20) dififactometer with Cu K monochromatic radiation. For the temperature-programmed desorption (TPD) experiments the catalyst (0.3 g) was pre-treated at diflferent temperatures (100-700 °C) under helium flow (5-20 Nml min ) in a micro-catalytic tubular reactor for 3 hours. The treated sample was exposed to methanol vapor (0.01-0.10 kPa) for 2 hours at 260 °C. The system was cooled at room temperature under helium for 30 minutes and then heated at the rate of 4 °C min . Effluents were continuously analyzed using a quadruple mass spectrometer (type QMG420, Balzers AG). 

The product gases were continuously analyzed for NO and NO2 using a chemiluminescent analyzer, and discontinuously for N2O, N2, CO, CO2 and O2 by GC equipped with a thermal conductivity detector and an electron capture detector, specifically for the N2O analysis, using a Poraplot Q column and a molsieve 5A column for separation. 

The reactor outflow was continuously analyzed by a set of detectors (Figure 5.4) ... 

Continuously analyze the value cycle of each product... 

FIGURE 10.1 Contrast between GCxGC and GC-MS. In the former, solutes are continuously analyzed in the second dimension, to ideally provide separation on D. In the latter, the MS will simply record all ions that arise from ionization processes in the source, regardless of... 

Miller, D. F., and C. W. Spicer. A Continuous Analyzer for Detecting Nitric Acid. Paper 74-17, Presented at 67th Annual Meeting of the Air Pollution Control Association, Denver, Colorado, June 1974. 

The analytic principles that have been applied to accumulate air quality data are colorimetry, amperometry, chemiluminescence, and ultraviolet absorption. Calorimetric and amperometric continuous analyzers that use wet chemical techniques (reagent solutions) have been in use as ambient-air monitors for many years. Chemiluminescent analyzers, which measure the amount of chemiluminescence produced when ozone reacts with a gas or solid, were developed to provide a specific and sensitive analysis for ozone and have also been field-tested. Ultraviolet-absorption analyzers are based on a physical detection principle, the absorption of ultraviolet radiation by a substance. They do not use chemical reagents, gases, or solids in their operation and have only recently been field-tested. Ultraviolet-absorption analyzers are ideal as transfer standards, but, as discussed earlier, they have limitations as air monitors, because aerosols, mercury vapor, and some hydrocarbons could, interfere with the accuracy of ozone measurements made in polluted air. 

In common industrial and laboratory continuous analyzers, the requirements on the magnitude of the cell are not as rigorous as with chromatographic, CFA and FIA detectors and thus the construction of the detector can be quite simple. The principal requirements are a sufficiently high and reproducible flow-rate in the vicinity of the ISE membrane, good electrical connection between the ISE and the reference electrode by the flowing liquid and, when a differential circuit is not used, placement of the reference electrode after the ISE to avoid possible interference from solution leaking from the reference electrode. 

Since taking samples of adsorbent from various positions in the bed for analysis is difficult, it is usual to deduce the shape of the adsorption front and the width of the MTZ from the effluent concentration profile which may be monitored with a continuous analyzer-recorder or by sampling. The overall width of the MTZ, for instance, is given in terms of the exhaustion and breakthrough times and the superficial velocity as... 

Replenishment should be done with care. Massive additions can cause decomposition. Maximum stability of electroless baths is obtained when continuous replenishment is practiced. Colorimetric analyzers are commonly used to control the addition of replenisher solutions in a set ratio based on the nickel or copper content of the bath. A number of machines are available that continuously analyze plating baths and make additions based on each separately analyzed component. 

Dead time. Probably the best example of a measurement device that exhibits pure dead time (time delay) is the chromatograph, because the analysis is not available for some time after a sample is injected. Additional dead time results from the transportation lag within the sample system. Even continuous analyzer installations can exhibit dead time from the sample system. 

An important advance in continuous analyzers uses both particle size data and single-particle chemical composition. These instruments employ a method of rapid depressurization of the aerosol that produces a particle beam and irradiation of particles to generate ions that are analyzed by mass spectroscopy. The single particle analyzers have been employed in atmospheric research recently but have not reached the stage where they are used routinely in air monitoring. 

We will continuously analyze and improve our practices, processes and products to reduce their risk and impact through the product life cycle. We will develop new products and processes that have increasing margins of safety for both human health and the environment... 

The ET is suitable for on-line monitoring of the raw milk sterilization process. Here, immobilized catalase is inserted into the ET, raw milk samples with H202 are automatically diluted within a FIA-system and continuously analyzed. Figure 19 shows on-line data of a H202 decomposition experiment. After addition of 0.1% H202 to raw milk, the ET signal increases tremendously whereas addition of catalase obviously causes H202 decomposition. Thus, raw milk s own catalase seems to have a too low activity. 

Flue Gas, Incineration flue gas was continuously analyzed by an automatic analyzer. The average value of analysis are shown in Table-VI. From oxygen concentration it is clear that char incineration can be made under the condition of very low excess air. 

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