27 February 2009 – RWE Power has officially commissioned the prototype plant for pre-drying lignite (WTA) at its coal innovation centre at the Niederaussem power plant location.
WTA technology reduces the water content of run-of-mine lignite from over 50 percent to 12 per cent. The decisive advance: In contrast to the previous drying process using 1000 degree Celsius flue gas, drying is carried out by WTA using significantly less energy at a temperature of 110 degrees.
In addition, the heat used for drying the coal is now largely recovered and used again. In the prototype plant, the peripheral combustion conditions during the firing of dry lignite on a large scale can now be investigated.
A licence has already been sold to Australia and discussions are being held with other countries. By using WTA, the efficiency of future lignite generation plants is to be increased by a further ten percent to 47 per cent.
Thus, at the same level of electricity production, a CO2 reduction of up to one million tonnes per annum will be possible in a power plant with a 1000 MW output.
110 tonnes of dry lignite is produced per hour by means of WTA. This represents up to 30 per cent of the total coal requirement of the BoA unit, currently the most modern lignite power plant in the world with an efficiency of over 43 per cent.
The result is a CO2 reduction of over 250 000 tonnes annually. RWE Power has invested €50m ($63.32m) in the project.
Fluidised bed drying is also an indispensable element of the IGCC power plant, which RWE Power intents to construct in Hürth by the beginning of 2015. In this plant, coal is to be gasified, separating the CO2 for subsequent storage.
The cost of this project (power plant plus pipeline and storage facility) is over €2bn – RWE is providing €1bn for this.