Greenbank Terotech Ltd - the development of an in-line real time density independent microwave sensor to measure moisture content of falling bulk materials used for coal fired power stations

Optimising the moisture content of pulverised coal fuel entering the boilers of coal fired
power stations provides significant boiler efficiency improvements. Moisture content in the
coal is managed by pre-heating the coal in the pulverising mill. The heat input is set based on
assumptions of the moisture content of the fuel typically from laboratory based checks
performed on a daily basis. This does not provide the opportunity to optimise the heat input
based on the real time variations in moisture content experienced in a modern operation.
Every 1 degree of unnecessary heat is estimated to waste £100k per hour. Existing microwave
moisture sensors are principally used in conveyor systems with single density materials and
are calibrated based on the assumed density and again do not provide the flexibility to cope
with the variation in density of a dynamic operation. The aim of the project is to develop the
first density independent in line real time microwave moisture sensor for falling bulk
materials intended to be installed in the coal feed chute of pulverising mills at coal fired
power stations. The project will apply novel microwave measurement processes in
challenging operational and environmental conditions. To deliver the project effectively
Greenbank Terotech will draw on the significant operational experience and microwave
sensor development knowledge within the group. The project will encompass a lab based
prototype development and will actively engage with a power station operator to trial a full
scale prototype in operation. The project is focused on coal for power stations but exciting
additional opportunities exist for the technology in a wide range of bulk material processing
industries such as cement, aggregates, and food processing