How To Measure False Air
How To Measure False Air
How To Measure False Air
Pyroprocessing
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Introduction
False air is any unwanted air entering the system between two points (see figure below). The exact
amount of false air is difficult to measure. An indicator of false air amount can be the oxygen increase
between two points (usable for gas stream containing less than 21% of oxygen).
point 1
point 2
gas
Objectives
Results
Prepare an action plan for reducing false air together with production and maintenance departments
Do measurement on a regular basis and follow-up on progress.
Safety aspects
Never make any measurement alone and without contact to the central control room operators.
Personal Protective Equipment is a requirement with special precaution in high temperature areas in the
lower pre-heater tower.
Prerequisites
Additional equipment: Sampling probes, coarse dust filter, fine dust filter and silica gel package for
drying.
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Sampling probes
Depending on the scope also installed oxygen analyzers can be used. ( take care about calibration)
Openings for measuring located with reference to false air critical parts (existing, accessible and open)
Time frame
Tools
Calculation formula:
Requirement: all values must be used on same basis, dry or wet. Recommendation is to do it on dry
basis. Be aware this is also valid for flow measurement.
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Action Steps
1.
2.
at the beginning (point 1) and at the end (point 2) of the inspected section (the shorter the section, the
easier it is to find leaks)
3.
4.
Simplified approach
5.
6.
Make sure that no chemical reaction influencing O2 content is taking place between point 1
and point 2 (decarbonisation, combustion)
Make sure that your measurement is not distorted by false air entering a measuring opening
(tighten free space around a measuring probe) Excel spreadsheet (check-list, calculation
sheet)
Reporting of false air on a wet basis is preferable. This requires the measurement or estimation of the
moisture content of the gases to make the conversion from dry to wet basis.