Abstract
We have developed a new hydrogen production process "HyPr-RING" where high pressure steam thermochemically decomposes organic materials such as coal with a calcium-based CO2 sorbent. In this study, the comparison of behavior of trace elements between in a batch and in a continuous reactor was studied. In the experiment with a small batch reactor, a mixture of pulverized Taiheiyo-coal and water with Ca(OH)2 was charged into a micro reactor. The reactor was put into a fluidized sand bath and rapidly heated to a subcritical condition. In the experiment with a continuous reactor, Taiheiyo-coal was charged into the fixed bed reactor. After the pressure in the reactor system was increased, the reactor was heated to a high temperature by using an electric furnace, and high temperature steam was continuously injected into the reactor below. In both experiments, the residual solid and liquid collected were analyzed with ICP-AES. Consequently, in the batch experiment conversions of most of metals into liquid were increased with reaction temperature, while in the continuous experiment they were hardly increased with temperature. In both experiments, conversions of most of metals into liquid occurred during pyrolysis and gasification in the initial stage. As the result obtained at 973 K, 19.8 MPa and 10 minutes in the batch experiment, Al, Fe and Mo were almost in the solid, while Mg, Ti, Cu, Zn and Pb were recovered in the liquid. However, it seems that Cu, Zn and Pb were partially in gas phase during reaction because they are easier to be volatilized. As the result obtained at 973 K, 6.0 MPa and 160 minutes in the continuous experiment, most of metals were only in the solid, while Zn was detected in the liquid. These experimental results almost corresponded with results of thermodynamic equilibrium calculation.
