石炭からの揮発分生成挙動を表す初期熱分解モデル

抄録

Primary pyrolysis is the first step of coal combustion or gasification reactions. Char and volatile matters form during the primary pyrolysis. Their yields directly affect the following reactions, such as char combustion, char gasification or gas phase reactions. The volatile matter compositions are also important because they affect gas phase reaction and soot formation behavior. Two kinds of primary coal pyrolysis models to predict the volatile matter formation behavior were proposed in literature. One is assuming the primary pyrolysis as a global type reaction. The other is considering coal chemical structures. The former models are used only for predicting volatile matter yields. Several researchers analyzed assuming the reaction as a first order reaction, the results were not consistent with each other. The distributed activation energy model which assumes that countless first-order reactions having different rate parameters occur in parallel, is one of the effective alternatives. In latter, there are three famous models considering coal chemical structure; the FG-DVC model, FLASH-CHAIN model and CPD model. Progress of coal chemical structure analysis techniques, such as a NMR method helps increasing prediction accuracy of these kinds of model. Furthermore, these models are expected to be applied for predicting volatile matter compositions. For example, the CPD model was extended for predicting volatile matter compositions. In the extended CPD model, we considered nine reactions of functional groups and bridges, and also determined an aromatic nucleus cluster size distribution by NMR analysis data and pyrolysis experimental data. The polycyclic aromatic hydrocarbon (PAH) formation behaviors which were simulated by the extended CPD model, were consistent with the soot formation behaviors in coal gasification experiments.