Effect of Different Chelating Agents on the Physicochemical Properties of Cu/ZnO Catalysts for Low-temperature Methanol Synthesis from Syngas Containing CO 2

Abstract

Methanol is the simplest primary alcohol manufactured worldwide in large quantities with an annual production of 40-60 million tons1). Methanol is a clean liquid fuel which can be used for fuel cells2). Methanol is extensively used for the production of dimethoxymethane (DMM), formic acid, dimethyl ether (DME), and other industrial chemicals3),4). More importantly, methanol is an intermediate for the synthesis of aromatics from syngas (CO+H2) or mixtures of carbon dioxide and hydrogen (CO2 +H2). These many applications emphasize the desirability of the development of highly active catalysts for methanol synthesis. The conventional high-temperature methanol synthesis process was developed by Imperial Chemical Industries Limited (ICI)2). However, the process achieves one-pass CO conversion of only 20-30 % because methanol synthesis is an exothermic reaction2). Therefore, recycling of unreacted feed gas is essential to increase conversion, leading to increased production costs. Consequently, methanol synthesis processes operating at low temperatures are very desirable. We previously proposed a novel reaction path of low-temperature methanol synthesis over Cu/ZnO catalyst using various alcohols as both promoters and solvents, which produced methanol at low temperatures (130-170 °C) in a slurry-phase reactor7),8). This new process can use syngas containing both CO2/H2O directly without further purification, since CO2 and H2O in the feed gas are both byproducts and reactants, so are recycled in-situ in [Regular Paper]