Превращений метана по принципу химического циклирования. Обзор приложений и измерения кислородной емкости

Abstract

Oxidative transformations of methane using a chemical looping (CL) principle are a novel method for valuable chemicals (syngas H[2]+CO, etc.) production. This method is based on the transfer of oxygen to methane by means of a cycling process using solid oxides as oxygen carrier materials (OCMs) to avoid direct contact between CH4 and gaseous O[2]. Syngas can be obtained through the heterogeneous reaction between methane and solid oxides (OCMs, or catalysts), and then OCMs in the reduced state can be regenerated by a gaseous oxidant, such as air or steam. The design and elaboration of suitable OCMs is a key issue in the optimization of CL-type processes. Here is presented a brief overview of the applications of supported metaloxide catalysts as OCMs, followed by the examples of Ni-containing samples used for the autothermal reforming (ATR) of CH[4], which is a combination of several reactions, mainly partial oxidation and steam reforming of methane (POM and SRM). Structural and electronic characteristics of the samples allow to estimate and experimentally check the oxygen carrying capacity (OCC), which is an important characteristic of OCMs.