Unit 48 Analytical and Chemical Composition Measurement




Unit 48:

Analytical and Chemical

 

 

Composition Measurement


Unit code:
A/601/1432

QCF level:
4


Credit value:
15






Aim

This unit will develop learners’ understanding of the techniques used in the detection of variables in industrial processes.

Unit abstract

The unit seeks to develop an understanding of modern measurement principles and recognition of how these concepts are applied in the design of commercial instruments for the measurement of both analytical and chemical composition variables.

Learning outcome 1 develops the principles, techniques and equipment used in process sampling. In learning outcome 2, learners will become familiar with the analytical measuring instruments used with a range of process variables. The final learning outcome considers the measurement of chemical composition and introduces the learner to a range of instruments, their principles of operation, design, selection and calibration.

Learning outcomes

On successful completion of this unit a learner will:

1       Understand the principles of process sampling

2       Understand the principles, design and operation of analytical measurement instruments

3       Understand the principles, design, operation and developments of chemical composition measurement instruments.




Unit content


1      Understand the principles of process sampling

Representative sample: process parameter; physical/chemical properties; probe location; sample conditioning; average sample; lags; intrusive/non-intrusive measurement

System components: sensor; signal conditioning; transmission; display; probe; filters; coolers; dryers; pumps; traps

Design and maintenance: environmental factors; temperature; pressure; humidity; corrosion; mechanical shock; leakage; blockage and contamination; frequency of site checks; inspection; routine maintenance and calibration; safety considerations

Design: nature of measurand; choice of materials; layout; dimensional limits


2      Understand the principles, design and operation of analytical measurement instruments

Principle of operation: gas analysers; dumbell; zirconium cell; electro-chemical cell; cooled mirrors; wet and dry bulb

Measurement: density; differential pressure; magnetic wind; frequency of vibration; absorption considerations eg radiation, moisture, fibres; hydroscopicity; capacitance; electrical conductivity; infra-red; viscosity; Newtonian/non-Newtonian fluids; capillary; torque

Design features: shaped vane construction; fixed aperture; accuracy; response; cost; environmental factors; scales

Selection: transducer; measurand characteristics; manufacturers’ data sheets

Evaluation: evaluation of an analytical measurement system eg calibration; standards; traceability; standard samples; storage life; standard procedures; safety

3      Understand the principles, design, operation and developments of chemical composition measurement instruments

Principle of operation: pH; acid; alkaline; hydrogen ion concentration; buffer solutions; ion and design specific electrode; glass electrode; calomel reference electrode; isopotential; point; measuring circuits

Measurement: redox oxidation, redox potential; conductivity eg atoms, molecules, ions, electrolyte, ionic concentration, cell constant; chromatography eg chemical extraction, partition coefficient, elution, peak resolution, carrier gas

Design features: evaluation of design features such as detectors eg thermal conductivity detectors, flame ionisation detectors, electron capture detectors; data presentation; construction accuracy; response; cost; environmental factors; sensitivity; accuracy of measurement

Selection: transducer; measurand characteristics; use of manufacturers’ technical data sheets to select transducer for given application

Evaluation: evaluation of a chemical composition measurement system eg calibration, standards, traceability, standard samples, storage life, standard procedures, safety

Learning outcomes and assessment criteria




Learning outcomes
Assessment criteria for pass


On successful completion of
The learner can:


this unit a learner will:










LO1 Understand the principles of

1.1
explain the importance of sampling and explain the need


process sampling


for provision of a representative sample




1.2
describe essential sample components for continuous





measurements in typical process systems




1.3
explain general design, maintenance and safety





considerations for typical sampling systems




1.4
design a sampling system








LO2 Understand the principles,

2.1
explain the principle of operation of analytical


design and operation of


measurement methods


analytical measurement

2.2
describe the design features of a range of analytical


instruments





measurement instruments









2.3
select the transducer capable of making a specified





measurement, using manufacturers’ technical data





sheets




2.4
evaluate a measurement system which is relevant to the





learner’s place of work







LO3 Understand the principles,

3.1
explain the principle of operation of chemical


design, operation and


composition measurement methods


developments of chemical

3.2
evaluate design features of thermal conductivity


composition measurement





detectors, flame ionisation detectors and electron


instruments






capture detectors









3.3
select the transducer capable of making a specified





measurement, using manufacturers’ technical data





sheets




3.4
evaluate a measurement system which is relevant to the





learner’s place of work.








Guidance

Links

This unit is designed to be stand-alone, but it has links with Unit 55: Instrumentation and Control Principles.

Essential requirements

Centres delivering this unit will need to provide access to industrial standard process instrumentation systems. A variety of system components will also need be available for demonstration purposes and hands-on familiarisation.

Employer engagement and vocational contexts

Visits to industrial installations will be of value to supplement learning activities and provide learners with a perspective on scale and application of instrumentation technologies.

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