Steam gasification of carbonaceous fuels in a rotary kiln reactor exposed to solar radiation: thermal and chemical structures

Abstract

Within the framework of the ANID/FONDAP/15110019 Solar Energy Research Center project, an experimental and numerical investigation was performed on the thermal and chemical structures inside a porous packed bed reactor operating under auto- and allothermal conditions for the steam gasification of carbonaceous fuels. An up-to-date literature review on thermochemical processes inside auto- and allothermal reactors is presented. Experimental research was conducted on the interactions of different mixtures of solid and gaseous fuels under various gasifier agents in lean, rich, and ultra-rich conditions inside inert and hybrid porous media autothermal reactors. High temperatures (1,100 K - 1,700 K) and [H2]/[CO] ratios ranging from 0.3 to 3.8 were observed, and interactions between homogenous and heterogeneous reactions were recognized. A comprehensive study of the solar steam gasification of coal in a rotational hybrid porous media reactor was conducted to analyze the effect of volatiles released by solid fuels in the thermal and chemical structure of the reactor [1], as well as to understand the heat transfer behavior of irradiated packed beds composed of different particles. These numerical and experimental results provided the design parameters to develop an allothermal version of the reactor. A solar experimental test bench, consisting of a 1.5 kWth two-stage concentration system, an elevated experimental platform, and an indirectly irradiated rotary reactor, was designed, and manufactured to evaluate the feasibility of operating an allothermal reactor filled with inert and fuel solid particles to produce H2 and syngas. Finally, new research facilities for concentrated solar thermochemistry applications were incorporated to the Renewable Energy Laboratory at the Federico Santa Maria Technical University.