Power & Energy › Incineration & Waste-to-Energy
Temperature measurement for waste incineration and waste-to-energy
Corrosive flue gas, abrasive particles and constant high temperatures make incineration one of the hardest environments a sensor can work in. The answer is not one sensor — it is the right thermocouple type, protection tube and mounting for each zone of the plant.
KP incineration temperature sensors are custom-built thermocouple assemblies for waste-to-energy and biomass plants — type K and N thermocouples for combustion and flue gas zones, and noble-metal type S, R and B for the hottest measuring points, ceramic-protected up to 1700 °C. Designed and manufactured by Kjaerulf Pedersen a/s.
Which sensor where? Zone-by-zone selection guide
A waste-to-energy plant measures temperature from the grate to the stack — and each zone calls for a different construction.
| Zone | Typical conditions | Recommended construction | Products |
|---|---|---|---|
| Combustion chamber & grate | High temperature, corrosive gases, slag and particle abrasion | Type K or N thermocouple in heat-proof steel sheath; ceramic inner tube where gases attack the element | TC-AM/AMC, TC-BM/BMC |
| Hottest zones & long-term stability | Highest process temperatures; drift unacceptable between service intervals | Noble-metal type S, R or B thermocouple with gas-proof ceramic protection — up to 1700 °C | AC/ACC, BC/BCC |
| Flue gas ducts & exhaust channels | Falling temperatures, condensing corrosive media, large duct diameters | Thermocouple with adjustable flange or coupling for correct immersion length | TC-AM/AMC, AC/ACC |
| Boiler, steam & water circuit | High pressure, vibration, service without process stop required | Pt100 or thermocouple in DIN 43772 weld-in thermowell, boiler steels 13CrMo44 / C22.8 — sensor replaceable without emptying the process | D/DS/DDS, MA-PW D |
| Confined & built-in points | Limited space, fast response needed, vibration | Bendable mineral-insulated thermocouple, up to 1800 °C depending on type | TM2, TM3, TM4 |
All constructions are configured to order: thermocouple type, sheath and ceramic material, immersion length, process connection and transmitter output.
When the measurement calls for noble metal
Type S, R and B thermocouples use platinum-rhodium alloys. Three conditions call for them:
Base-metal thermocouples have an upper working limit. For the hottest zones, noble-metal types measure reliably up to 1700 °C in a gas-proof ceramic protection tube.
Noble-metal elements drift less in continuous high-temperature service — fewer recalibrations, fewer surprises between service intervals, better process documentation.
Platinum-rhodium elements are vulnerable to contamination from aggressive flue gas. A gas-proof ceramic protection tube keeps the process atmosphere off the element, so it holds its characteristic through continuous service.
Frequently asked questions
Which thermocouple type should I use for waste incineration?
For combustion zones and flue gas up to roughly 1100–1200 °C, type K or type N are the workhorses — type N offers better stability at sustained high temperatures. Above that, or where long-term stability is critical, noble-metal type S, R or B with ceramic protection is the right choice, measuring reliably up to 1700 °C.
What is the difference between type K, N, S, R and B?
K and N are base-metal thermocouples, suited to most combustion measurements. S and R use platinum-rhodium/platinum elements and B uses platinum-rhodium in both legs; they cover the highest temperature ranges with superior drift stability.
How do you protect a thermocouple against corrosive flue gas?
Three lines of defence: a heat-proof steel outer sheath (4C54 as standard, special materials available), a gas-proof ceramic inner tube (KER610 or KER799) that stops aggressive gases from contaminating the element, and correct zone-based selection so each sensor matches the conditions it measures in.
Can a sensor be replaced without stopping the process?
On the boiler, steam and water side, yes: D/DS/DDS sensors sit in DIN 43772 weld-in thermowells, so the sensor is exchanged without emptying or interrupting the process. In the combustion zones, sensors are direct-mounted and replaced as part of planned service.
Why are noble-metal thermocouples so expensive?
The elements contain platinum and rhodium — precious metals. They are specified where the measurement demands it: noble-metal thermocouples measure reliably up to 1700 °C and drift far less than base-metal types in continuous high-temperature service. A gas-proof ceramic protection tube keeps aggressive flue gas off the element, so it holds its characteristic through its working life.
Do you also cover the steam side of a waste-to-energy plant?
Yes — Pt100 sensors and high-pressure D/DS/DDS sensors in DIN 43772 weld-in thermowells, rated up to 500 bar and 650 °C depending on material, for boiler, steam and water circuits, plus bearing and surface sensors for turbines and fans. See the full Power & Energy programme.
Get a zone-by-zone sensor recommendation
Send us your measuring points — zones, temperatures, media and existing mountings — and our experts will configure the right assembly for each one.