Climate change and ultra-clean coal

A NEW chemical process for removing unwanted minerals from coal could lead to reductions in carbon dioxide emissions from coal-fired power stations.

Problems with cleaning


There is already a way of burning coal in a cleaner, more efficient fashion that would reduce carbon dioxide emissions: this is where the coal is turned into a gas and used to drive a turbine.

Generating electricity in this way very expensive, however, due to problems with cleaning the coal before it is burnt. This new chemical process could make it more commercially viable.

Under development by a University of Nottingham team, using chemicals to dissolve unwanted minerals in the coal and then regenerating the chemicals again for re-use is involved in the new approach.

This avoids the expense of using fresh chemicals each time, as well as the need to dispose of them, which can have an environmental impact according to a University of Nottingham press release.

Preventing corrosion


The new process helps protect the turbines from corrosive particles by removing unwanted minerals before the coal enters the power plant.

The aim is to cut unwanted minerals in coal from around 10 per cent to below 0.05 per cent, making the coal `ultra clean'.

Before using the coal to generate power removing these minerals prevents the formation of harmful particles during electricity production.

Specific chemicals are used to react with the minerals to form soluble products, which can be separated from the coal by filtration. Hydrofluoric acid is the main chemical being tested. The chemicals not only dissolve the minerals but are also easy to regenerate .



— OUR BUREAU



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