Reducing mercury emissions using lignite coke (HOK®)

Two versions of process: “dry” in continuous operation/ “wet”

The technology for mercury emission reduction which is in operation today has been tested in a demonstration unit in Niederaussem before.

The purpose of the demonstration system was to refine and perform long-term testing of innovative versions of procedures to reduce mercury emissions in flue gas from lignite/coal-fired power stations using lignite coke (HOK®) in continuous, automated operation
Full-scale system at a flue gas train at the BoA1 lignite power station in Niederaussem, volumetric flow of flue gas approx. 1.6 m³_N/h
HOK® supply for “wet” and “dry” versions from shared silo container
Expansion of mercury system to supply both flue gas trains at BoA1 in subsequent commercial operation
Project executed by the technical services of RWE Power and RWE Technology International
Contractor: ISS Schüttguttechnik GmbH
Demonstration operation since beginning of 2019

Dry version includes:

Dosing and simultaneous distribution to 16 nozzles via pneumatic delivery lines
Delivery supply and compressed air supply
Variation of injection speed for optimum penetration depth and even distribution of HOK®

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Dry version includes:

Wet version includes:

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Wet version includes:

R&D programme by RWE to reduce mercury emissions

Lignite coke or activated coke (HOK®) is produced from Rhenish lignite using the hearth refining process.
HOK® has a large specific surface area and a favourable pore radius distribution, with a large proportion of mesopores and macropores.
The pore diameter of 1 to > 50 nm enables easy access to the inner surface.