Hydrogen-rich gas production through supercritical water gasification of chicken manure over activated carbon/ceria-based nickel catalysts

摘要

In recent years, supercritical water gasification has attracted the attention of scientists and environmentalists not only as an alternative method for direct disposal of poultry manure, but also as an efficient hydrogen-rich gas generation process. In this study, by varying the temperature (375-450 degrees C), residence time (5-35 min), and feed concentration (2.5-3.5 wt%), some non-catalytic supercritical water gasification tests were designed and carried out in a stainless-steel U-type batch reactor to assess the optimum operational condition. To stimulate hydrogen production, catalytic experiments were conducted using the optimized condition (450 degrees C, 15 min, and 2.5 wt% of feedstock). The prepared catalyst supports and final nanocatalysts (Ni/Activated carbon, Ni/activated carbon-CeO2 nanorods) were then thoroughly characterized by various analytical instruments to verify the differences between the metal oxide-free and composite-like catalyst supports. Moreover, elemental analysis, gas and liquid chromatography were conducted to provide a deep understanding toward the impacts that composite-like catalyst support could have on diversity and quality of products. The experimental results revealed that, although in catalytic experiments the H-2 yields were higher than those recorded in non-catalytic experiments, highest hydrogen selectivity of 36.42 % could be achieved when Ni/activated carbon-CeO2 nanorods were employed.