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Composition sensors

Composition sensors. Submitted to Dr – Ing Naveed Ramzan Submitted by Qamar Munir. Importance of composition sensors. These are much important because of the following reasons Production of pure compounds Qualitative analysis of compounds Prevent production of wrong material.

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Composition sensors

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  1. Composition sensors Submitted to Dr –IngNaveedRamzan Submitted by QamarMunir

  2. Importance of composition sensors • These are much important because of the following reasons • Production of pure compounds • Qualitative analysis of compounds • Prevent production of wrong material

  3. Types of testing • There are two basic types of measuring composition • On-line composition testing • Off-line composition testing

  4. Important composition sensors • There are large number of composition sensors used in the industry. A few of them are explained here. • Chromatographic composition sensors • Photometric composition sensors • Electrical composition sensors • Electro analytical composition sensors

  5. Chromatographic Instruments • It is a technique used to separate and analyze the mixtures for composition measurement. • It involves two phases, one mobile phase and other is stationary phase. • Chromatography is of two types i.e. preparative and analytical.

  6. Working principle • Separation occurs in the column based on varying affinities of the components to bind column packing. A detector measures some physical property that relates to concentration. • The smaller the affinity a molecule has for the stationary phase, the shorter the time spent in a column

  7. Classification of chromatography • There are many types of chromatographic sensors depending on different basis. • Basis :Mobile phase • Liquid chromatography • Gas chromatography • Supercritical chromatography

  8. Contd. • Basis : Bed shape • Column chromatography • Planar chromatography • Paper chromatography • Thin layer chromatography

  9. Contd. • Basis : Stationary phase • Ion exchange chromatography • Size-exclusion chromatography • Adsorption • Partition • Affinity

  10. Contd. • Special techniques: • Reversed-phase chromatography • Two-dimensional chromatography • Simulated moving-bed chromatography

  11. Advantages • This technique can be used to find chemical composition of almost every compound. • These are very precise and accurate. • It is very accurate method for the identification of the drugs and sometimes used for quantitative analysis.

  12. Disadvantages • Lag time • Off-line • Expensive • Only used for known mixtures

  13. Photometry • Photometric analysis is a technique used for measurement of the intensity of visible light and other electromagnetic (EM) waves. • There are many photometric devices available for composition measurement in the chemical industry.

  14. Classification of photometers • There are two main classes of photometry on the basis of the instruments used. • Spectrophotometers • Photometers using visible light

  15. Working principle • The degree of absorption /radiation reveals molecular structure and concentration of a sample. • Higher the absorption more will be concentration and vice versa.

  16. Advantages • These are highly sensitive and are very specific. • These are reliable. • These have large data bank for reference. • These are relatively inexpensive and can be used for a variety of substances.

  17. Disadvantages • Spectrophotometers are too specific for a given application. • Application is limited to certain electromagnetic range. • These photometers can only be used for transparent mixtures. • Photometer that uses visible light is less stable.

  18. Conductivity probes • These measure the composition by measuring the electrical conductivity. • It works on the following principle R=f (T) = f (k) = f (composition) Where T is the absolute temperature,k is thermal conductivity

  19. Advantages • These are very cheap and simple in construction. • Conductivity probes are stable in operation and are accurate. • These are corrosion resistant and are easily cleaned. • These are the online composition sensors

  20. Disadvantages • Only used for small scale operation and cannot be used on large scale. • As conductivity depends on many other factors like temperature, structure etc. so these may affect the reading. • The calculations are complicated if the components present are large.

  21. Electro analytical composition measuring techniques • These are as follows • pH sensors • Ion specific • polarography

  22. Physical composition sensors • Some of these are as follows • Displacement hydrometer • Direct mass measurement • Radiation density gauges

  23. Conclusion • There are no general rule for selection of the composition sensors. • Each composition sensor is specific for some specific application • So a thorough study is required to select composition sensors

  24. ANY QUESTIONS ?

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