Instrumentation process flow change

The XRT method is better suited than XRF for the process control of sulfur in crude oil. Future work is required to determine the response time of the instrument to step changes in sulfur concentration and to test flowing conditions of the sample. 

Data collection, organization, and analysis are equally important parts of troubleshooting process problems. Process flow diagrams (PFDs) are used to quickly identify the primary flow path and the control instrumentation being used in the process. Checksheets are used to collect data that can be graphically organized or charted to show trends and reveal process variation or changes. Data analysis utilizes a variety of quality techniques to pinpoint process problems and potential issues. 

The main objectives in calibrating the SEC detection system in absolute refractive index and absorption units are the estimation of v and E at the normal flow conditions and the standardization of the measurement errors. The first step in the calibration process is the estimation of the instrument s constants to transform the computer units into absorbances and refractive index units. The Waters AAO UV spectrophotometer displays absorbance units. Therefore, step changes in the instrument s balance and sampling of the signal provide the necessary data for the calibration. The equations obtained are ... 

The need for more complicated considerations in conversion of instrument response to mixing ratios usually arises when instruments that are based on mass-sensitive detectors are used. Common reasons are either that the mass flow is not held constant or that the process whereby the flow of analyte molecules is converted to an electrical signal changes as the pressure changes. These effects are illustrated by a discussion of the pressure response of two instruments commonly used to measure atmospheric trace gases, both based on detection schemes that are inherently mass sensitive. 

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