Why is Flue Gas Desulphurisation fitted at Rugeley?

The fuel burnt at all coal fired power station contains sulphur in varying quantities that, when burnt in the two boilers at the power station, reacts with oxygen in the air to produce sulphur dioxide, which is a major contributor to the production of acid rain.

As part of the Government’s drive to reduce the UK's contribution to acid rain, coal and oil-fired power stations in the UK were subject to much tougher sulphur dioxide emission targets from 2008 onwards. FGD is one of the techniques being used to control these emissions.

Installation of FGD allowed continued clean coal fired generation at Rugeley. This will increase fuel diversity in the UK.

How Does FGD Work?

FGD is a simple chemistry process that uses limestone slurry (powdered limestone mixed with water) sprayed into a tank called an absorber through which the boiler exhaust gasses pass. The limestone slurry reacts with the sulphur dioxide in the exhaust gas to produce first calcium sulphite and then, with air blown through it, forms calcium sulphate, which is better known as gypsum.

The gypsum is removed as slurry from the absorber, piped to a dewatering plant for drying and stored prior to being sold for use in plasterboard. The water removed from the gypsum is returned to the absorber for re-use. The small amount of wastewater is treated to meet standards set by the Environment Agency before being released from the site into the River Trent.

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