It is now impossible to imagine industry without flue gas desulphurisation (German: “Rauchgas-Entschwefelungs-Anlagen” or REA). It uses a limestone solution to filter sulphur dioxide (SO2) from the flue gas of lignite power plants. Today, more than 95 percent of desulphurisation units in power plants and industrial facilities around the world operate reliably and successfully using this technology. RWE does not, however, see the current high level of effectiveness of flue gas cleaning as a reason to become complacent. Instead, it motivates the company to develop new processes to make coal-fired power generation even more environmentally friendly in the future. This is the background to the REAplus concept, which we have implemented in partnership with Austrian plant constructor Andritz Energy & Environment (AE&E) as a test facility at the RWE Innovation Centre.
REAplus makes pre-treatment of flue gas unnecessary and saves resources
This concept involves further optimising the chemical processes involved in desulphurisation. The innovation lies in the stage-by-stage scrubbing process and improved contact between the limestone suspension and CO2 from the flue gas via what is known as the “Plus module”. The test facility cleans 50,000 cubic metres of flue gas hourly from the lignite-fired power plant. The facility is testing the intended filtration targets and suitability for permanent operation. High-efficiency desulphurisation with REAplus also means that pre-treatment of the flue gas in the pilot CO2 scrubbing facility at the same unit is not necessary.
Pilot facility at Niederaussem power plant sets new standards over long term
The combination of REAplus and post-combustion capture at the Niederaussem site is creating conditions that are unique worldwide for testing modern, pioneering power plant technology. However, the technology could also be of interest to existing REA absorbers; after the successful operation of the pilot facility, a Plus module was integrated into an industrial REA absorber at Unit G of the Niederaussem power station in July 2014. The performance results for the Plus module, gathered over several months, were positive. At certain SO2 levels in the flue gas, the module is able to reduce the electricity consumption of the REA. Two further absorbers at Unit H were therefore equipped with this technology in 2015.