Abstract:
Pyrolysis is an attractive thermochemical conversion technology that may be utilised as a safe disposal option for acid tar waste. The
kinetics of acid tar pyrolysis were investigated using thermogravimetry coupled with mass spectrometry under a nitrogen atmosphere
at different heating rates of 10, 15 and 20Kmin-1. The thermogravimetric analysis shows three major reaction peaks centred around
178°C, 258°C, and 336°C corresponding to the successive degradation of water soluble lower molecular mass sulphonic acids,
sulphonated high molecular mass hydrocarbons, and high molecular mass hydrocarbons. The kinetic parameters were evaluated
using the iso-conversional Kissinger–Akahira–Sunose method. A variation in the activation energy with conversion revealed that the
pyrolysis of the acid tar waste progresses through complex multi-step kinetics. Mass spectrometry results revealed a predominance
of gases such as hydrogen, methane and carbon monoxide, implying that the pyrolysis of acid tar waste is potentially an energy
source. Thus the pyrolysis of acid tar waste may present a viable option for its environmental treatment. There are however, some
limitations imposed by the co-evolution of corrosive gaseous components for which appropriate considerations must be provided in
both pyrolysis reactor design and selection of construction materials
