流動層ガス化炉における合成ガス中のタール成分の分析に関する研究

抄録

  Gasification is one of the methods for efficiently utilizing solid fuels such as biomass and coal. A fluidized bed gasifier usually operates at low temperature and can handle fuel more easily. For these reasons, construction cost is low and maintenance is easy. However, the high concentration tar is generated together with syngas. The tar discharged to outside the gasifier is processed by methods for instance, high temperature reformers, scrubbers, or adsorption by activated carbon. This brings about increase in running costs. The traditional evaluation index of the tar is concentration in the syngas, for example “g/m³_N”. It's necessary to elucidate the details of tar composition to optimize a gasification system. The purpose of this study is to analyze in detail the tar produced by using a laboratory-scale fluidized bed gasifier. The experimental condition is steam gasification of lignite at 1123K. The conventional methods for measuring the tar are gas chromatograph mass spectrometry (GC/MS) and gas chromatograph flame ionization detector (GC-FID). These methods are suitable for identification of low-molecular compounds in tar. Additionally, the new measuring methods, which are field desorption mass spectrometry (FD-MS) and matrix assisted laser desorption mass spectrometry (MALDI-MS), were adopted in this study. The molecular weight distribution of tar is clarified by these methods. As results, it was found that the tar, which was obtained by the gasification experiment, contains polycyclic aromatic hydrocarbon (PAH) with molecular weight range in 100-600 mainly. Therefore, details of tar in syngas, which is produced by steam gasification of lignite, was clarified by a number of analytical methods such as GC/MS and FD-MS.