Performance of combined cobalt—nickel—zirconia and HZSM‐5 catalyst systems for carbon monoxide hydrogenation

Abstract

The synthesis of hydrocarbons via hydrogenation of carbon monoxide was investigated over cobalt-nickel-zirconia catalysts of various compositions in combination with zeolite HZSM-5 in "mixed bed" and "follow bed" arrangements. These combinations resulted in the formation of aromatics in amounts as high as 30-35 wt% under relatively mild operating conditions (1 atm, 250-280°C). Although the olefinicity of Cr and C, fractions in the product stream was higher in the mixed bed compared to the follow bed arrangement, the selectivities to aromatics were comparable in the two bed arrangements. The aromatic selectivity was found to be sensitive to operating conditions. The formation of aromatics was favored at high HZSM-S/metal catalyst ratios, low space velocities and high reaction temperatures. The product distributions obtained using various metal/zeolite bifunctional catalysts have been discussed.

Conversion of Syngas to LPG and Aromatics Over Commercial Fischer-Tropsch Catalyst and HZSM-5 in a Dual Bed Reactor

“…Contrarily, Freitez et al (2011) reported a decrease in cracking activity with a ZSM-5 temperature increase. In addition, the observed effect of maximum selectivity of aromatics at 573 K is in agreement with the results obtained by Varma et al (1985), Varma and Bakhshi (1987), and Karre et al (2013), who also reported an increase of aromatization reactions with a HZSM-5 temperature increase up to 573 K. A negative effect of a HZSM-5 temperature increase was also observed for the selectivity toward CH 4 and C 2 , which increased up to 10.8% and 1.1%, correspondingly. Figure 1 shows the effect of HZSM-5 temperature on the individual product selectivities of DB reaction, C 3 -C 4 paraffins ( Figure 1a) and aromatics ( Figure 1b).…”

Selective Production of C4 Hydrocarbons from Syngas in a Dual Reactor Using Co−Ni/ZrO2 and SO42-/ZrO2 Catalysts

“…10,17 Effect of Reactor 2 Temperature. Experiments were performed in the dual-reactor setup wherein the first reactor containing a CNZ catalyst was kept at 523 K and WHSV of 15 h -1 , and the reactor 2 temperature was varied from 373 to 523 K and the catalyst ratio was maintained at 1:1.…”

Direct conversion of synthesis gas to aromatic hydrocarbons: Variation of product distribution with time‐on‐stream

“…It was chosen based on some recent studies (Bruce et al, 1982(Bruce et al, , 1983Varma et al, 1985b) over a variety of nickel-zirconia and cobaltnickel-zirconia preparations. As a result, the ageing characteristics of the catalyst as reflected in the timeon-stream variations of the product distribution have gained little attention.…”

“…As a result, the ageing characteristics of the catalyst as reflected in the timeon-stream variations of the product distribution have gained little attention. These catalysts mixed with an excess volume of HZSM-5 can give aromatic selectivities approaching 30 wt% under mild reaction conditions (Bruce et al, 1984;Varma et al, 1985b). A cobalt-nickel-zirconia catalyst was used as the FT component.…”

“…A cobalt-nickel-zirconia catalyst was used as the FT component. It was chosen based on some recent studies (Bruce et al, 1982(Bruce et al, , 1983Varma et al, 1985b) over a variety of nickel-zirconia and cobaltnickel-zirconia preparations. It has been reported that cobalt-nickel -zirconia catalysts prepared by impregnating cobalt and cobalt-nickel mixtures onto a co-precipitated nickel-zirconia support exhibit good activity and selectivity for Fischer-Tropsch reaction (Bruce et al, 1983).…”