Online analyse

The use of chemically informative online analysers in the early stages of route development enable identification of critical processing parameters. 

On the basis of the deconvolution method and the developed software, SECOMAM Company commercializes two spectrophotometers, a portable instrument (PASTEL UV) and an online analyser (STAC), presented in Figure 2.4.1. 

Concerning the STAC, this online analyser is composed of three main boxes (sampling system, a Diode Array polychromator, a control box) allowing to isolate the major fluidic circuits from the electronic one. 

For natural water, STAC can provide water quality monitoring with continuous multi-parametric determination and nitrate measurements. This online analyser could be also very efficient in case of accidental pollution detection in particular for organic contaminants or in case of urban WWTP dysfunction investigation. 

Most online systems, when used in the capacity of control rather than monitoring, establish a set-point for entrained air at a particular place in the papermaking system and allow the defoamer addition rates to change. In other words, the entrained air levels as measured by the online analyser are used to adjust the dose rates of the defoamer/deaerator additives. 

Exit flue gas composition can indicate excess or low feed of fuel oil (or combustible reactants such as sulphur, ammonia). Provide online analyser for C02 %, free oxygen %, etc. or check gas analysis by Orsat apparatus. Test exit gases for sooty particles by clean filter paper for any excess oil feed. 

Multistage absorber NO2 is absorbed into DM water to achieve the maximum yield If the multistage system fails, production of acid will be less Install online analyser for NO and NO2... 

Multielement analytical techniques - atomic absorption spectrometry, inductively coupled plasma mass spectrometry. X-ray fluorescence, neutron activation analysis, etc. - are used. The experimentation can be done directly on the mineral matter of the coal sample after the removal of the organic matter by a prolonged treatment of activation with oxygen plasma (low-temperature ashing). Neutron activation is also applied to online analyses of coal and fly-ashes on feeding-belts in order to provide information on a continuous basis. 

Looking first at the online analyses, extrudate API concentration (< Capi >) is generally considered a CQA, and the API standard deviation (oapi) is an indicator of process control. When PAT enables online measurement of API concentration, both measurements can be quickly captured as a function of operating conditions and equipment scales. PAT also enables straightforward measurement of the residence time distribution (RTD Bigert and Smith-Goettler 2011). If the RTD and product... 

In addition to the online analyses described, offline tests are also required. Specifically, standard release tests such as a product s dissolution profile and any degradation products must be assessed. If not obtained online via PAT, the assay and content uniformity of extrudate must be measured via off-line lab tests. Any residual solvents (including water) should be measured as they can have a plasticizing effect potentially influencing both extrudate physical and chemical stability. Finally, tests such as differential scaling calorimetry (DSC), X-ray diffraction (XRD), or others must be conducted before and after holding the product at controlled environmental conditions, to ensure that the phase state of the extrudate is understood and controlled over time. 

With the rise of NIR reflection instrumentation and chemometric data treatments for rapid, direct control measurements, the interest in NIR for industrial applications became greater again. Process control applications, either rapid laboratory measurements or real-time online analyses, benefited the most from the new technologies. Older applications, such as hydroxyl number, polymer properties, water measurement, and fuel analyses have been revisited. 

In laboratory with constant measurements conditions (laser intensity, laser spot diameter and so on) the line intensity (Ij) of the certain element is proportional only to its concentration (N,) in sample. Thus having number of the reference samples with known concentrations of desired elements one can cOTistruct the calibration dependence (liOcNi). For online analyses of materials on moving belt conveyer the measurement conditions are constantly changing and it is obligatory to construct the calibration dependence for each element as relation (Ij/IoOcNi) where (Iq) is the line intensity of the element, which concentration is constant during the measurements, thus (li/Io) will depends only on Ni and not on experimental conditions. 

A detailed cost/benefit analysis of expensive sensors, like online analysers, is available early in the project. 

The component fraction C3 in the bottoms mimics an online analyser controller. 

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