2020 Volume 63 Issue 2 Pages 62-69
Gasification technology converts a solid fuel to syngas, and it has wide utility for power generation and hydrogen production. In a dual fluidized bed gasifier, the fuel is gasified with steam. As the gasifier operates at 1073-1173 K, tar is generated in the syngas, and a tar reformer such as a catalytic reforming tower is normally required. To ensure optimal reformer design, it is important to clarify the components of the tar. In this study, the components of tar were investigated using a laboratory-scale fluidized bed gasifier to gasify lignite at 1123 K, employing wide variations in the amount of supplied steam. As the steam supply increased, the tar concentration decreased. In addition, a prediction method in real time of the tar concentration in the syngas which is varied by the amount of steam supplied to the gasifier from the analysis of the hydrogen and carbon monoxide produced was proposed. The tar components were analyzed using various hyphenated techniques such as gas chromatograph mass spectrometry (GC/MS) and field desorption mass spectrometry (FD-MS). The main components detected were polycyclic aromatic hydrocarbons (PAHs) without any substituent groups. It was shown that even if the steam was supplied at triple the required stoichiometric ratio, the tar composition was unchanged.
