Study on heterogeneous reactions between tar and ash during coal gasification

[出版社版]In coal gasification, it is one of the problems to sub-generated tar. To solve this trouble, we focus attention on that major components of ash contain calcium oxide (CaO) that is known as catalyst can decompose tar, and thought whether the tar was able to be decreased by using the ash in gasification furnace. The purpose of this study is to demonstrate reactions between tar and ash during coal gasification, and to estimate effect of tar decrease by ash. In this study, toluene, CaO, and Carbide from phenol resin was selected as the model tar, model ash, and model carbon, respectively. Experiments were carried out by passing toluene to CaO in flow fixed-bed reactor under increasing temperature (25～900 ℃, 10 ℃/min), and under constant temperature (700 ℃ and 900 ℃) for 5 h. As a result, it is turn out that CaO is effective to decreasing toluene. The rate constant when toluene decompose with CaO is about 58 times as large as rate constant when toluene decompose without CaO at 700 ℃, is about 30 times at 900 ℃. Also, although model carbon didn’t affect toluene conversion, when toluene decompose with CaO combined model carbon, benzene yield is decreased from it when toluene decompose with nothing