Direct synthesis of DME over nanostructured CuO-ZnO-Al2O3/HZSM-5 catalyst washcoated on high pressure microreactor: Effect of catalyst loading and process condition on reactor performance

Direct conversion of syngas to DME (STD) has been successfully implemented over CuO-ZnO-Al2O3/HZSM-5 catalyst coated over a micro-channel reactor. Effect of catalyst loading (0.02, 0.025 and 0.03 g) coated over the microchannels has been investigated and physiochemical properties of the coatings were examined by FESEM, EDX Dot-mapping, EDX Line-mapping and adherence sonication test. Although higher amounts of catalyst loading resulted in enhancement of active phase numbers but due to the thicker layer of catalyst, distance of diffusion was longer. Higher loadings of catalyst led to high coverage of top surface by copper and zinc but to weaker adherence of catalyst layer to the micro-channel plate. With increasing catalyst loading from 0.02 to 0.025 g, the CO conversion and DME yield significantly enhanced but with increasing catalyst loading from 0.025 to 0.03 g, the improvement in CO conversion and DME yield was not noticeable. The CO conversion and DME yield significantly decreased at high feed flow rates in the case of high loadings of catalyst. (C) 2014 Elsevier B.V. All rights reserved.