Temperature sensors monitor biomass energy production

Allerod, Denmark – Energi Randers Production of Denmark is employing specially develoiped thermocouple assembly sensors for use in its production of electricity and heat by burning 100 tonnes/day of biomass.

The Danish company commissioned Ametek Calibration Instruments to manufacture six-metre-long versions of its AMK thermocouple assembly sensors. The units, which have a steel protective tube and an interchangeable ceramic inner tube, are used to monitor temperatures of around 1200 – 1300 degrees C in two boilers as part of a new flux firing system.

Temperature control is critical in the process since the biomass -- olive cores, and meat and bone meal -- must be ignited so that it burns at once, to avoid possible gas explosions. The high temperature also ensure that any spores or bacteria from the fuel mass are destroyed and dioxins from the process are completely burned.

The sensor is mounted through the top of the furnace to a depth of approximately 700 mm. The fuel enters the two boilers on a conveyor belt to ensure continuous combustion.

Each boiler is equipped with two of the special sensors, and a spare was supplied for use when a sensor is re-calibrated. In view of the length of the sensors, Ametek developed a new system to allow recalibration while the boiler continues to operate.