Rehan T ariq O7-chem-64

1. Online Composition Measuring Sensors RehanTariq O7-chem-64

2. Outline • Introduction • Desireable sensor attributes • Why online sensors…? • Advantages • Methods of composition measurement • ORP Sensor • Gas Chromatography • Liquid Analyzer

3. Sensor/Analyzer A sensor is defined as a device that converts a physical stimulus into a readable output, and the definition is illustrated with several examples of engineered and biological senssors. Engineered sensors Biological sensors

4. Desirable Sensor Attributes All sensors, whether used individually or as part of a larger automatic control system, need to meet a set of specifications, i.e., performance features • Reliability • Safety (including intrinsic safety) • Accuracy • Fast response • Wide dynamic range • Low cost • Low power • Small size, compactness • Low cross-sensitivity • Ruggedness • Compatible output and display • Corrosion resistance • Cleanliness

5. Why Online Sensors…….? Recent trends and developments in sensor technology include • The increasing use of signal processing for compensation • Typically used for reducing cross-sensitivity to secondary variables • Multivariable inferential sensing Above points allow sensing solutions to be developed for parameters that are infeasible to directly measure online; and self-checking and self-compensating sensors that enhance reliability and reduce maintenance costs.

6. Advantages • On-line analysis include an immediate and continuous feedback responding to changes in process condition. • More efficient process guidance (e.g. increase in product quality) • Increased process safety • Transparency of the measuring data in realtime

7. Methods of Composition Measurement • Various physical property measurement(i.e density & specific gravity) • Photometric analysis • Mass spectrometry • Electrometric analysis • Chromatography • Thermal conductivity

8. ORP Sensors

9. ORP Sensor ORP stands for (oxidation-reduction potential), which is a measure of the tendency of a chemical substance to oxidize or reduce another chemical substance in mili-volts. • Reference electrode • Measuring electrode Constructional Parts

10. Difference of Reference & Measuring Electrodes Reference Electrode: The reference electrode, usually made of silver which is surrounded by salt (electrolyte) solution that produces a tiny voltage ORP electrode: The ORP electrode is made up of an inert metal electrode (platinum, sometimes gold), which, due to its low resistance, will give up electrons to an oxidant or accept electrons to from a reluctant.

11. Working Principle • The voltage that is produced by the reference electrode is constant and stable so it forms a reference against which the voltage generated by measuring electrodes and oxidizers in the water may be compared.

12. uses ORP meter is utilized worldwide in many industries and also for commercial purposes. Some of those are • Aquarium Monitoring • Chromate Reduction • Drinking Water • In multiple chemical systems • Swimming Pool Water • ORP measurement in cyanide destruction, dechlorination, chromate reduction Sometimes the exchange of electrons between the ORP electrode and certain chemical substances is disturbed by a low rate of electron exchange. In these cases, ORP may respond more strongly to a second redox couple in the solution (like dissolved oxygen). Limitations

13. Gas Chromatography

14. Gas chromatograph A gas chromatograph is a chemical analysis instrument for separating chemicals in a complex sample. Intrinsically, with the use of the flame ionization detector and the electron capture detector gas chromatography can quantitatively determine materials present at very low concentrations. Detectors

15. Instrumental components • Carrier gas • Sample injection port • Columns • Detectors Gas chromatography - specifically gas-liquid chromatography - involves a sample being vapourised and injected onto the head of the chromatographic column. The sample is transported through the column by the flow of inert, gaseous mobile phase. The column itself contains a liquid stationary phase which is adsorbed onto the surface of an inert solid. Working:

16. Uses Main application of gas chromatography is in gasoline industry. Because multi-components are involved there and there separation and detection is done there. • It is used for detection purposes of multi target chemicals. • Used for biological and bio-chemical processes. • Treats drug abuse detection, toxicological problems and the determination of heavy metals in blood plasma.

17. Liquid Analyzer

18. Liquid Analyzer Liquid analyzer provides a reliable and cost effective monitoring tool that is speciallydesigned to accurately monitor chemical composition of process streams. By reliably monitoringprocess streams it provides a vital tool to improve product quality and consistency, optimize productionyields, reduce raw materials, eliminates rejects and reduces time consuming and costlylab analysis.

19. construction It consist of following parts • Reactor portion and associated • measurement potion • Sample pump • Base pump for supply of base solution • Ozone generator • Optical detector

20. Working principle The principle of operation requires a continuous free flowing liquid sample into a heated oven where the sample Transfer Stripper (S.T.S) unit separates the liquids from the gas sample. An undesired free air or nitrogen carrier then sweeps the undesired gas sample to the analyzer for quantitative analysis in ppb, ppm, and up to saturation levels. The detection technology is based on chemically specific density changes. The sensing tape utilized in this analyzer is the only detection method that is absolutely specific to measured gas.

21. Applications Typical applications include • A variety of refining operations, ( S, V, Ni, Fe, Cl, Pb in fuels) • Blending operations (Ca, Zn, P, S, Cl and Ba) • Plating bath composition monitoring (Co, Ni, Zn, Cr, P etc.) • Fluid catalyst monitoring and recovery (Co, Mn, Br, Fe, Pt, Rh, Pd etc.) • Water treatment monitoring • Ca and Ti additive monitoring in Pulp and Paper industry • Monitoring of wood preservatives like As, Cu and Cr

22. Any Question?????