二甲醚合成催化剂失活原因的研究

采用胶体沉积法制备了Cu-ZnO-ZrO2／HZSM-5二甲醚合成催化剂．对二甲醚合成过程中催化剂的失活原因进行了初步研究．采用BET，NH3TPD，TPD，TP0和N2O脉冲实验对催化剂使用前后比表面积，表面酸性，表面吸附物种，表面积碳和活性组分Cu比表面积的变化进行了研究．发现，在二甲醚合成过程中，催化剂表面酸性，催化剂表面吸附物种和表面积碳变化较小，不是导致催化剂失活的主要原因．而催化剂在使用过程中活性组分Cu烧结使Cu比表面积降低是催化剂失活的主要原因．

The Study on Catalyst Deactivation for Direct Synthesis of DME

Dimethyl Ether (DME) is an important chemical and has potential to be an ideal substitute for diesel or liquefied petroleum gas. In recent years, DME direct synthesis from synthesis gas has attracted much attention in research fields and industrial fields for its low cost and low energy consumption. The published papers focused mainly on the studies about catalysts preparation and characterization, the influence of promoters and supports on the catalysts performance, the effects of reaction condition and feed gas composition on the catalysts activity, kinetics and mechanism for DME synthesis. However, the study of catalyst deactivation during the DME synthesis was seldom mentioned in the literature. In this paper, BET, NH_3-TPD, TPD, TPO and N_2O Pulse Flow Experiments were carried out to investigate the deactivation of DME synthesis catalyst Cu-ZnO-ZrO_2/HZSM-5 derived from colloid sedimentation method. The results indicated that the catalyst deactivation did not result from the change in specific area, the acidity, the absorption species and carbon deposition on the catalyst during the DME synthesis process. The main reason for DME catalyst deactivation is the Cu sintering, which results in the decrease of specific surface area and dispersion of the active Cu species. Moreover, the results showed that it is useful for inhibiting the Cu sintering to synthesize DME using the syngas containing N_2 obtained by air partial oxidation of natural gas.