Useful experimental technique for the study of heterogeneous reactions

The heterogeneous CaO/SO₂ reaction has been thoroughly investigated by developing a series of new experimental techniques including the TGA reactor, the volulmetric reactor and the entrained flow reactor. The heterogeneous system is designed in such a way that most of the gas film and pore diffusion resistances are reduced. The modelling of each step related to the reaction is discussed while the chemical reaction and product layer diffusion are emphasized as the main influences on the SO₂removal. The unchanging size shrinking core model is used to describe the reaction progress with a two stage assumption which has been confirmed in the TGA reactor: first, a very fast surface reaction, followed by a product layer diffusion controlled reaction. It was found from the experiments that the SO₂-partial pressure aat the very beginning is very important for a high removal efficiency during the initial reaction period.