Catalyst CuZnAl

Table XII. Modelling the Methanol Synthesis in a bubble column slurry reactor (catalyst CuZnAl)...

S. Velu, K. Suzuki, M. Okazaki, M. P. K oor, T. Osaki, andF. Ohashi, Oxidative steam reforming of methanol over CuZnAl(Zr)-oxide catalysts for flie selective production of hydrogen for fuel cells Catalyst characterization and performance evaluation, J. Catal. 194,373 (2000). 

The catalyst bed was a coated wall reactor using commercial CuZnAl catalyst. An alumina sol was used to enhance the adhesion of the catalyst to the channel walls. After the shims were washed thoroughly, the alumina adhesion layer was deposited using an alumina sol (NYACOL AL20DW colloidal alumina, PQ Corporation) and then dried at 60 °C. To decrease the surface tension of the wash-coat solvent, small amounts of 2-propanol were added to a catalyst slurry of ICI Synetix 33—5 catalyst, with 20 wt % alumina sol and water. The catalyst was calcined at 350—400 °C for 2 h after air-drying. Before testing, the catalyst was reduced by flowing H2/N2 over it at 280 °C. 

To process the methanol and water mix, a CuZnAl catalyst was wash-coated onto the microchannel walls. The alumina was deposited by dipping the plates into a 20% alumina suspension, which also included a stabilizer and a binder. After any excess was wiped off, the plates were calcined at 600 °C for 1 h in air. Air was removed from the pores by placing the calcined plate in a vacuum. The alumina wash-... 

Velu S, Suzuki K. Selective production of hydrogen for fuel cells via oxidative steam reforming of methanol over CuZnAl oxide catalysts effect of substitution of zirconium and cerium on the catalytic performance. Top Catal. 2003 22(3-4) 235-44. 

Table 2.24. Physicochemical Properties of CuZnAl(Zr) Oxide Catalysts Tested in the Oxidative Steam Reforming of Methanol177...

Murcia-Mascaros, S., Navarro, R.M., Gomez-Sainero, L., Costantino, U., Nocchetti, M., and Fierro, J.L.G. Oxidative methanol reforming reactions on CuZnAl catalysts derived from hydrotalcite-like precursors. Journal of Catalysis, 2001, 198 (2), 338. 

Velu, S., Suzuki, K., and Osaki, T. Selective production of hydrogen by partial oxidation of methanol over catalysts derived from CuZnAl-layered double hydroxides. Catalysis Letters, 1999, 62 (2), 159. 

Figure 2 shows the behavior of the catalysts as a function of time on stream at 310 °C. Some of the samples were tested for more than 60 h because 40-50 hours were necessary for the CuZnAl s ple to obtain pseudo steady-state conditions. The sudden decreases in the conversion curves are caused by instability of the feed. The conversion obtained with the CuZnAl sample, dropped from an initial value of about 10 % to 5.5 % after 60 h on stream. However, even after 60 h on stream a slight deactivation could be observed. 

The commercial catalyst discussed above was also studied as a function of time on stream. The conversion decreased at about the same rate as for the CuZnAl sample prepared by flame spray pyrolysis. After 25 hours on stream the commercial sample and the CuZnCeAl have almost the same conversion level. 

M. J. L. Gines, N. Amadeo, M. Laborde, C. R.Apesteguia, Activity and structure-sensitivity of the water-gas shift reaction over CuZnAl mixed oxide catalysts, Appl. Catal. A Gen. 131 (1995) 283-296. 

Figure 26.2 CuZnAl catalyst washcoatings prepared with a poly(vinyl alcohol) binder (left micrograph) and a Tylose binder (right micrograph).

ZnCr- and CuZnAl-LDOs. LDO catalysts generally give rise to high selectivity for methanol, while surface doping with Cs on mixed oxides increases catalyst stability (162,610-612). Higher alcohols can be also obtained with similar catalysts but at higher temperature and with a lower CO/H2 ratio (610,611). The doping of alkali, such as Cs, promotes the formation of branched alcohols (613). In addition, Ru supported on LDH-derived oxides, exhibits substantial selectivity toward alcohols, mainly methanol, at moderately low pressures (614). 

Garcia-Trenco, A. Martinez, A. Direct Synthesis of DME from Syngas on Hybrid CuZnAl/ZSM-5 Catalysts New Insights into the Role of Zeolite Acidity. Appl Catal A Gen. 2012,411 12, 170-179. 

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