Methanol synthesis from CO2 using a silicone rubber/ceramic composite membrane reactor

A one-dimensional isothermal pseudo-homogeneous parallel flow model was developed for the methanol synthesis from CO2 in a silicone rubber/ceramic composite membrane reactor. The fourth-order Runge-Kutta method was adopted to simulate the process behaviors in the membrane reactor. How those parameters affect the reaction behaviors in the membrane reactor, such as Damkohler number Da, pressure ratio p(r), reaction temperature T, membrane separation factor alpha, membrane permeation parameter phi , as well as the non-uniform parameter of membrane permeation L-1, were discussed in detail. Parts of the theoretical results were tested and verified; the experimental results showed that the conversion of the main reaction in the membrane reactor increased by 22% against traditional fixed bed reactor, and the optimal non-uniform parameter of membrane permeation rate, L-1.opt ,does exist. (C) 2003 Elsevier B.V All rights reserved.

Influence of composition of heteropolyphosphatotungstate catalyst on epoxidation of propylene

A series of heteropolyphosphatotungstate catalysts with different W/P ratio were prepared by different means. P-31 MAS NMR spectra show every heteropolyphosphatotungstate contains several species with different W/P ratio. Combined with propylene epoxidation results, it is shown that the band at chemical shift ca. delta = 5 ppm maybe corresponds to a catalyst precursor which can be the most efficiently converted to the structure {PO4 [WO(O-2)(2)](4)}(3-). Characterization results of ICP show, the catalysts with low W/P ratio show a good reactivity for propylene epoxidation. (C) 2004 Elsevier B.V. All rights reserved.