Intro to Analyzers and Terminology Flashcards
What is analysis?
Quantitative or qualitative determination of constituent parts. The determination of chemical components or intrinsic physical properties of a mixture
Define qualitative Analysis
The determination of WHAT is in the sample e.g. a gas chromatograph determines there is propane present in a gas
Define quantitative analysis
The determination of HOW MUCH is in a certain sample e.g. a gas chromatograph determines that propane represents 19% of a gas in the sample volume
What is an analyzer
An instrumentation device that the continuously monitors a process stream unattended.
A measurement system can determine:
a) Chemical composition; provide one or more quantitative analysis of component
b) Physical properties; boiling point, vapor pressure, and pour point
What is a process analyzer
Analyzers for process fluids that generally have a higher expected concentration
What is a compliance analyzer
An analyzer for low values of concentration.
This can be:
An emission monitor; does not measure process but rather monitors smoke stacks, wastewater or ambient air
Safety monitor; gives warnings about hazardous conditions in the workplace such as presence of H2S
Define grab sample
A process sample that is manually taken out of the process and is transferred to an analyzer.
What are the three characteristics of an on-line analyzer?
1) Connected to a process in order to obtain a sample
2) Actively measuring
3) Actively sending data
State five ways that analyzers can have a positive impact on plant operations.
1) Ensure product quality
2) Reduce downtime
3) warn of hazardous atmospheres
4) Reduce emissions
5) Lower operating costs
What is the main disadvantage of having a sensor installed at a distance away from the process?
The ambient temperature can greatly effect the sample during transport
_________ is also another way to describe a sensor that is “in-line”.
in-situ
While in use, is a personal safety monitor considered on-line?
Yes as it’s:
1) Is constantly monitoring the ambient air
2) Actively measuring
3) Actively sending quantitative data about the atmosphere
Briefly describe calibration of an analyzer by use of the standard sample method.
Standard sample method involves taking the analyzer offline, taking a gas mixture with known concentration (standard) and then adjusting the zero and the span of the analyzer (two point calibration).
Describe calibration of an analyzer by use of the paired sample method.
A grab sample is analyzed offline in a lab and the results are then used to calibrate the analyzer online. The time of grab sample needs to be taken into account as process can change over time.
Describe the characteristics of an ideal zero gas for setting an analyzer to zero.
An ideal zero gas will be devoid of the substance that trips the analyzer in order to get a zero reading.
Can IAS be used as zero gas for a CO2 analyzer?
Since IAS contains some CO2 ppm it would need to be passed through an activated charcoal filter.
What is absolute standardization method?
The analyzer calibrates itself by simulating zero and span properties.
After the lab result, it is determined that the online fluoride ion
analyzer should be calibrated using calibration solution. This
is _________.
Standard Sample Method
How are gas mixtures that offer the highest level of accuracy prepared and what are they
called?
Primary Standard gas mixtures are prepared gravimetrically meaning that every component is weighed on a special analytical balance.
Why can’t some gasses be mixed no matter what the cylinder pressure is?
1) Reactivity with other components
2) Reactivity with the container
3) Flammability
Mixtures of flammable gas and air to be stored in high pressure cylinders may be
prepared if what condition is followed?
50% or less of the flammable gas LEL
List 3 sample conditions that are needed to calibrate a composition analyzer.
1) Temperature
2) Pressure
3) Flow rate
4) Phase
What makes an ideal span gas?
A gas made of the same concentrations as expected in the process but all components and concentrations are known exactly.
