Direct desulfurization

The desulfurization in the high temperature range of 900 - 1,100°C by adding chalk granulations is state of the art.

1. CaCO₃ -> CaO + CO₂
2. CaO + SO₂ + 1/2 O₂ -> CaSO₄

In the first step at temperatures > 850°C, chalk is converted into calciumoxide with a high specific surface. In the second step, the actual reaction with sulfur dioxide (SO₂) to produce gypsum takes place

The most eco friendly combustion of coal takes place in the fluidized bed, because at low combustion temperatures the NOx emissions are kept very low here, and because due to the direct addition of grained chalk into the firing place, a technically simple and efficient desulfurization is carried out.

In comparison with other limestone granulations of older genesis, chalk used for the desulfurization process shows the following advantages:
 

• High porosity
• Low reaction time for neutralization and generation of CaO
• High specific surface of CaO
• Low stoichiometry

The products Calciumcarbonat 5, Calciumcarbonat 15, Calciumcarbonat 45, Calciumcarbonat 90 and Calciumcarbonat Perlkalk can be used.