Cu/ZnO-based water–gas shift catalysts in shut-down/start-up operation

Impact of Daily Startup–Shutdown Conditions on the Production of Solar Methanol over a Commercial Cu–ZnO–Al2O3 Catalyst

“…In addition, the consequences of a DSS schedule on the kinetics and mechanism of catalyst deactivation vis‐a‐vis a typical continuous operation should be explored. In this respect, testing of such a ternary system in the water–gas shift reaction (CO+H 2 O⇄CO 2 +H 2 ) with DSS at atmospheric pressure and 473–523 K has evidenced activity loss as a result of the generation of mixed Zn–Al hydroxides and hydroxycarbonates during shutdown when a CO 2 ‐containing aqueous condensate forms over the catalyst . Whereas H 2 O is one of the main components in the gas feed upon the water–gas shift process, the extent to which the formation of H 2 O during MeOH synthesis affects the stability of the catalyst has not been demonstrated.…”

“…In this respect, testingo fs uch at ernary system in the water-gas shift reaction (CO + H 2 OQCO 2 + H 2 )w ith DSS at atmospheric pressure and 473-523 Kh as evidenced activityl oss as ar esult of the generation of mixed Zn-Al hydroxides and hydroxycarbonates during shutdown when aC O 2 -containing aqueousc ondensate forms over the catalyst. [11] Whereas H 2 Oi so ne of the main components in the gas feed upont he water-gas shift process,t he extent to Methanol production with the use of syngas derivedf rom solar-drivens plittingo fC O 2 and H 2 Oi sapromising route to sustainable liquid fuels.H erein,w ei nvestigated the effect of using aC O 2 -rich syngasw ith the same compositiona st hat obtained in as olar thermochemical reactor and of applying ad aily startup-shutdown( DSS) routinem atching the intermittents olar operation over ab enchmark Cu-ZnO-Al 2 O 3 catalyst.T he catalyst reached fast equilibration( 10 h) in the presenceo ft his syngasm ixture and reversibly responded to changes in the concentrations of CO and CO 2 by mimicking fluctuations in the feed composition. Remarkably,i ts deactivation was even less pronounced over 27 cyclesu nder aD SS regime than for ac orresponding time on stream under uninterrupted operation if the reactor was purged with H 2 -free syngas upons hutdown.…”

Ethanol steam reforming on Ni/Al2O3 catalysts: Effect of the addition of Zn and Pt

“…A clear decrease in the CO production due to Zn addition can be observed, and this may be explained by the ability of both nickel and zinc oxides to promote the water-gas shift reaction (CO + H 2 O ? -CO 2 + H 2 ) [38,39]. In fact, TPR results have shown that the reduction temperature at which the catalysts have been submitted before reaction is not as high as to reduce all Ni(II) species and all Zn(II) in ZnAl 2 O 4 , and these species can promote the watergas shift reaction.…”

Pt and/or Pd Supported/Incorporated Catalyst on Perovskite-Type Oxide for Water Gas Shift Reaction

“…So the reaction temperature should be lowed to achieve higher CO conversion, on the other hand the reaction rate is suppressed kinetically at low temperature. In industrial processes, WGS is performed with two catalytic processes; high temperature shift (HTS) and low temperature shift (LTS), HTS has high CO conversion near equilibrium with Fe 2 O 3 -Cr 2 O 3 catalyst at high temperature region (583-723 K) and LTS is performed with Cu/ZnO/Al 2 O 3 catalyst for decreasing CO level to less than 1% at low temperature region (483-523 K) [4][5][6][7][8][9][10][11][12]. Pt/CeO 2 catalyst also shows high conversion at low temperature.…”