Water-gas shift (WGS) Operation of Pre-combustion CO2 Capture Pilot Plant at the Buggenum IGCC

AbstractIn the Nuon/Vattenfall CO2 Catch-up project, a pre-combustion CO2 capture pilot plant was built and operated at the Buggenum IGCC power plant, the Netherlands. The pilot consist of sweet water-gas shift, physical CO2 absorption and CO2 compression. The technology performance was verified and validated models were obtained. This paper describes the validation of a WGS reactor model and the excellent catalyst resistance to carbiding at steam/CO=1.5 mol·mol-1 testing. Model-based optimization shows that compared to conventional operation at steam/CO=2.65, applying steam/CO=1.5 leads to a 10% lower CO2 capture of penalty of 1155 MJelectric·tCO2−1, albeit at a decreased optimum CO2 capture efficiency of 78.5% versus 87.5%

Coke formation in the oxidative dehydrogenation of ethylbenzene to styrene by TEOM

A packed bed microbalance reactor setup (TEOM-GC) is used to investigate the formation of coke as a function of time-on-stream on gamma-Al2O3 and 3P/SiO2 catalyst samples under different conditions for the ODH reaction of ethylbenzene to styrene. All samples show a linear correlation of the styrene selectivity and yield with the initial coverage of coke. The COX production increases with the coverage of coke. On the 3 wt% P/SiO2 sample, the initial coke build-up is slow and the coke deposition rate increases with time. On alumina-based catalyst samples, a fast initial coke build-up takes place, decreasing with time-on-stream, but the amount of coke does not stabilize. A higher O-2 : EB feed ratio results in more coke, and a higher temperature results in less coke. This coking behaviour of Al2O3 can be described by existing "monolayer-multilayer" models. Further, the coverage of coke on the catalyst varies with the position in the bed. For maximal styrene selectivity, the optimal coverage of coke should be sufficient to convert all O-2, but as low as possible to prevent selectivity loss by COX production. This is in favour of high temperature and low O-2 : EB feed ratios. The optimal coke coverage depends in a complex way on all the parameters: temperature, the O-2 : EB feed ratio, reactant concentrations, and the type of starting material.</p

Gold on titania : effect of preparation method in the liquid phase oxidation

The effect of prepn. method (deposition-pptn. vs. sol immobilization method) and redn. method (calcination vs. chem. redn.) on Au/TiO2 catalysts for the liq. phase oxidn. of glycerol has been studied. It was revealed that a different trend existed in terms of activity and distribution of products. The catalytic activity is shown to be dependent not only on the choice of the redn. method but also on the use of protective agent (PVA, THPC) for the stabilization of the gold colloids. In fact, the highest activity was found when a low temp. chem. redn. was employed on a Au/TiO2 sample synthesized by the deposition-pptn. method. The use of a higher pre-treatment temp. or of a protective agent resulted in a lower activity but could be used to direct selectivity in oxidn. reactions. The structural data (HRTEM and XPS) along with the catalytic results indicate that the combination of metallic Au0 species with small particle size (2-5 nm) are responsible for the high activity obsd. in the liq. phase oxidn. of glycerol

Combined action of Enzyme and Metal Catalyst, applied to the preparation of D-Mannitol

Applied Science

Adverse effects of potassium on NO_x reduction over Di-Air catalyst (Rh/La-Ce-Zr)

The influence of potassium in Rh on a lanthium promoted zirconia stablised ceria (CZ) catalysts was studied toward NOxreduction reactivity and selectivity. The results are compared with a Rh/CZ catalyst. The samples were characterised by N2 adsorption, XRD, SEM, ICP, and H2-TPR. The study highlighted the importance of stored NOx regeneration over potassium in determining the overall performance of the Rh/K/CZ catalyst. The NOx stored over Rh/K/CZ in the previous NO gas stream cannot be regenerated sufficiently during the C3H6 gas stream, and stored NOxgradually decreased from one cycle to the next, resulting in deteriorating performance of Rh/K/CZ. Besides, problem of NOx slip, the formation of both NH3 and N2O (selectivities up to 30% for each side product) were observed by the addition of potassium into the Rh/CZ catalyst system, depending on the reaction conditions applied and the severity of the catalyst deactivation.ChemE/Catalysis Engineerin