Highly Effective Transformation of Methanol and RFCC Gas to Propylene and Paraxylene with Tungsten Hydride and Cerium Oxide Comodified HZSM-5 Zeolite

Abstract

HZSM-5 zeolite was comodified with tungsten hydride and cerium oxide. A fixed-bed reactor was used to investigate the performance of the resulting catalysts in the transformation of methanol and residual fluid catalytic cracking (RFCC) gas to propylene and paraxylene. The resultant samples were characterized using the XRD, SEM, and BET techniques. X-ray diffraction analysis indicated the coexistence of WH x and CeO2 in the catalysts. Only at suitable methanol/RFCC gas ratios could relatively good propylene and aromatics yields be obtained. Addition of RFCC gas to methanol inhibits dry gas production while promoting the production of propylene and paraxylene and decreases the consumption of water. The methanol conversion, the propylene yield, and the paraxylene yield reached 100%, 69.5%, and 20.0%, respectively, under suitable conditions of a silica/alumina ratio of 150, a reaction temperature of 743 K, a space velocity of 10 h–1, and an RFCC gas content of 9%.

Effect of Metal Active Sites on the Product Distribution over Composite Catalysts in the Direct Synthesis of Aromatics from Syngas

“…The ammonia peaks at about 220 and 440 °C were assigned to weak and strong acid sites, respectively. 44 The acid sites of parent HZSM-5 zeolites were in general derived from framework aluminum. 37,45 Compared with parent metal loading slightly widened the peak of weak acid sites and reduced the peak of strong acid sites on the order of Nb-Ni > Ni > Nb.…”

Integrated Catalyst of CuZnAl‐Zr and Nb‐HZSM‐5 for One‐Step Synthesis of Aromatics from Syngas

“…The desorption peaks at 130 and 350 °C were assigned to weak and strong acid sites, respectively. [ 25 ] Compared with the parent HZSM‐5 zeolite, the Nb modified HZSM‐5 zeolite's peaks were obviously wider at the weak acid position and the amount of weak acid sites were increased, and the result has been shown in Table 2. Nb loading also slightly shifted the strong acid sites to high temperature compared with parent HZSM‐5.…”

“…Similar results were also observed by other researchers. [ 8,25 ] As a result, the gaseous products of C 1 —C 4 decreased, which increased selectivity of aromatic hydrocarbons, especially the heavy aromatics C 10 and C 10+ .…”