Model Selection Guide

Type of Process or Appliance

Usual Process Conditions

Sensor Location(s)

Measuring Range

Models Used

Comments

Boilers 

Package 

Combusted gas or fuel oil 

Flue 

0.1 to 5% O2 

1732 & 1231 

Probe insertion length is usually 250mm 

Power Generation 

Combusted Coal, dusty fly-ash 

Economiser Outlet 

0.1 to 5% O2 

1732, 1231 & FIL-2 

If the probe can be mounted vertically downwards then filters are not required but the purge should still be used. Some fly-ash is abrasive. 

Combusted Oil 

Economiser Outlet 

0.1 to 5% O2 

1732 & 1231 

Don’t use filters with oil fired appliances 

Combusted Wood Chips, ash 

Economiser Outlet 

0.1 to 5% O2 

1732, 1231 & FIL-2 

Vertically down for the probe or else use filters; purge required 

Black Liquor Recovery 

Combusted Black Liquor, dusty 

Economiser Outlet 

0.1 to 5% O2 

1732, 1231 & FIL-2 

Large amounts of hydrated sodium sulphate & water vapour, use filters and purge (Na2SO4 =90%; Na2CO3 =10%) Dust Loading 5 to 15 g/Nm3 

Iron & Steel 

Heating Furnace 

Combusted Gas 

Preheat, Heating & Soaking Zones 

0.1 to 5% O2 

1732, 1231 & S/Chamber 

Gas flow ˜ 5 lpm, back-purge required 

Annealling Furnace 

H2Nx (indirect fired) 

Base of Furnace 

1 x 10-26 to 1 x 10-20% O2 

1738 & 1231 

4 – 5 years life at BlueScope Steel, Westernport works 

Coke Oven 

Combusted Gas 

Flue 

0.1 to 5% O2 

1732 & 1231 

Use filters if gas contains particulate 

Soaking Pit 

Combusted Gas 

Before Recuperator 

0.1 to 5% O2 

1732 & 1231 

Minimise ingot surface oxidation 

Aluminium 

Potlines & Holding Furnace 

Hostile component – fluoride 

Sampling point from hood 

< 1% O2 

1732, 1231 & S/Chamber 

Alco, Pt Henry, ˜ 5 year sensor life 

Incinerators 

PVC 

Combusted Gas & HCl 

Sample point from after-burner outlet 

0.1 to 5% O2 

1732, 1231 & S/Chamber 

High HCl use condensate / acid trap before sample chamber 

Medical or Toxic Waste 

Combusted Gas & hostile compounds 

Sample point at the final combustion chamber outlet 

0.1 to 5% O2 

1732, 1231 & S/Chamber 

Keep distance between sample point & chamber to a minimum to minimise transport lag time 

High Temp Kilns / Furnaces 

Rotary Lime 

Combusted Gas 

Kiln end 

0.1 to 5% O2 

1732, 1231 & FIL-2 

Probe location is critical; large amounts of abrasive dust and tramp air 

Cement 

Combusted Gas (and sometimes rubber) 

Cyclone outlet 

0.1 to 5% O2 

1732, 1231 & FIL-2 

Often used to incinerate rubber from spent vehicle tyres 

Glass 

Combusted Gas (high silica) 

Sample point from kiln roof 

0.1 to 5% O2 

1732, 1231 & S/Chamber 

High silica destroys zirconia catalyst >800°C 

Ceramic 

Combusted Gas (high glazing flux) 

Sample point from reduction firing zone 

< 1000ppm O2 

1732, 1231 & S/Chamber 

Glazing salts are hostile to the sensor >800°C, sample tube between sample point & chamber require periodic replacement due to salts condensing in tube 

Brick 

Combusted Gas (high glazing flux) 

Sample point from reduction firing zone(s) 

< 1000ppm O2 

1732, 1231 & S/Chamber 

Same as ceramic kilns 

Heat Treatment 

Sealed Quench Furnace 

CO / CO2 (reducing) 

Side mount 

0 to 1.5% Carbon 

1734 & 1232 253MA 

Use purge to burn-out carbon build-up around the sensor 

Rotary Furnace 

CO / CO2 (reducing) 

End mount 

0 to 1.5% Carbon 

1734 & 1232 253MA 

These are usually “dirty” furnaces, use purge to burn-out carbon build-up around the sensor 

Mesh Belt Furnace 

CO / CO2 (reducing) 

Side mount 

0 to 1.5% Carbon 

1734 & 1232 253MA 

These are also usually “dirty” furnaces, use purge to burn-out carbon build-up around the sensor 

Nitrogen Purity 

Generator 

Clean nitrogen 

Sample drawn from outlet 

< 100ppm O2 

1732 & 1234 

Use MOZ-1 for OEMs 

Oxygen Enrichment 

Generator 

Oxygen & Nitrogen 

Sample drawn from outlet 

90 to 95% O2 

1732 & 1234 

1234 must be degreased for pure oxygen service 

Drying Ovens 

Direct Fired 

Water Vapour 

Side mount probe and sample tube 

20 to 40% water vapour 

1735, 1231 & RGS-17 

Used in textile industry, gypsum dryers, paper machine drying hoods 

Indirect Fired 

Water Vapour 

Side mount probe 

20 to 40% water vapour 

1735 & 1231 

Baking Ovens 

Indirect Fired 

Water Vapour & fat 

Side mount probe 

10 to 99% water vapour 

1735 & 1231 

Avoid direct jets of water on probe during wash-down 

Food Packaging 

Food Packs – Spot Checks 

Clean gas 

Hypodermic with septum to sample package gas level 

1 ppm to 5% O2; 0-100% CO2 

1637 Mk-II 

Use the white particulate filters if dust is present, use the blue filter to block water if droplets are in the work area or food pack, use septum to seal the hypodermic through the food pack. 

Continuous Monitoring 

Clean gas 

Gas drawn from the packaging machine sample point 

1 ppm to 5% O2 

1732 & 1234 

Use the activated carbon filter if hydrocarbons are present in the gas stream 

Laboratory Use 

Clean gas 

Analyse take-up rate of CO2 and O2 permeation of package film 

1 ppm to 5% O2; 0-100% CO2 

1637 Mk-II 

The instruments are well looked after in most of these facilities