Heynderickx, Philippe

Marin, Guy

Poelman, Dirk

Poelman, Hilde

Thybaut, Joris

English

Ghent University Academic Bibliography

The experimental data are regressed by a Mars-van Krevelen (MVK) model. This model corresponds to a reduction step inwhich propane reacts with a single oxidized site and with a reoxidation step by gas phase oxygen, involving a singlereduced surface site.A CuO-CeO2/γ-Al2O3 catalyst synthesized by impregnation with nitrate precursorsis the best catalyst for the oxidation of propane from a series of four copperoxide and ceria-based catalysts. Whereas the reduction step seems to be themost critical step in the reaction mechanism on Cu-based catalysts, it is thereoxidation that is critical on a CeO2 based catalyst. A mixed oxide CuO-CeO2/γ-Al2O3 allows combining the good characteristics of both types of oxides in asynergetic way. A precursor effect is observed by using two copper oxidecatalysts, made by impregnation of Cu(NO3)2 and CuCO3 on θ-Al2O3. The lattercatalyst shows higher propane conversion as well as TOF.Acquisition of experimental dataIntroductionVolatile organic compounds (VOC’s) exhibit a significantly high vapour pressureat ambient conditions. These VOC’s are responsible for increased levels of ozonein the troposphere and for_ozone depletion in the stratosphere. According toTheloke and Friedrich, one third of all emitted VOC’s are alkanes [1]. Emissionsfrom both stationary and non-stationary sources are subjected to an ever stricterlegislation, due to an increasing environmental awareness. Catalytic oxidationoffers the advantage over thermal incineration that these VOC’s can be removedfrom effluent streams in low concentrations and at relatively low temperatures[2]. This paper describes the total oxidation of propane as model reaction overCu- and Ce-based catalysts by means of steady-state experiments.pC3H8,0 = 0.58 kPapO2,0 = 3.51 kPaT = 621 K(■) CuCe-N(○) Cu-N(□) Cu-C(●) Ce-N* Corresponding author: joris.thybaut@ugent.be *OAcknowledgementsConclusionsFACULTY OF ENGINEERINGSynergetic and precursor effects in propane total oxidation over Cu- and Ce-based catalystsPhilippe M. Heynderickxa, Joris W. Thybauta,*, Hilde Poelmana, Dirk Poelmanb, Guy B. Marinaa Laboratory for chemical Technology, department of Chemical Engineering, Ghent University, Ghent, B-9000, Belgiumb Department of Solid State Sciences, LumiLab, Ghent University, Ghent, B-9000, BelgiumFour catalysts are used: a CuO-CeO2/γ-Al2O3, catalyst, formally denoted as CuCe-N, synthesized by impregnation of a γ-Al2O3 carrier with precursors Cu(NO3)2 andCe(NO3)4; catalysts Cu-N and Cu-C are made by impregnation of θ-Al2O3 withCu(NO3)2 and CuCO3; a Ce-N catalyst is obtained by impregnation of a γ-Al2O3carrier with Ce(NO3)4.These four catalysts are tested in the total oxidation of propane using aconventional plug flow reactor with a propane and oxygen inlet partial pressureof 0.58 kPa and 3.51 kPa at three temperatures: 595, 621 and 648 K. For sampleCe-N, an extra temperature level of 634 K is applied. The space time is varied upto 570 kgcat s mol-1.pC3H8,0 = 0.58 kPapO2,0 = 3.51 kPa(■) CuCe-N(○) Cu-N(□) Cu-C(●) Ce-N[1] J. Theloke, R. Friedrich, Atmos. Environ. 41 (2007) 4148. [2] J.J. Spivey, Ind. Eng. Chem. Res. 26 (1987) 2165.[3] P.M. Heynderickx et al., Appl. Catal. B 90 (2009) 295.ResultsThis work was performed in the framework of a Concerted Research Action(GOA), financed by Ghent University. The project 1.5.201.07 sponsored bythe FWO-Vlaanderen is also gratefully acknowledged. This work has alsopartly been performed within the IAP-PAI framework sponsored by theBelgian Science Policy.catalyst kO2,0 / mol molO-1 s-1 Pa-1 EO2 / kJ mol-1 kC3H8,0 / mol molO-1 s-1 Pa-1 EC3H8 / kJ mol-1 θO* / -CuCe-N (2.01 ± 0.65) 10-1 47.2 ± 3.5 (3.29 ± 1.07) 10+0 74.9 ± 5.5 0.45 ± 0.32Cu-N (2.46 ± 0.72) 10-1 50.8 ± 2.4 (1.39 ± 0.41) 10+0 78.5 ± 3.7 1.11 ± 0.20Cu-C (1.14 ± 0.17) 10+1 72.4 ± 2.9 (6.27 ± 0.91) 10+1 95.3 ± 3.8 0.75 ± 0.28Ce-N (2.11 ± 0.62) 10+0 77.9 ± 4.4 (2.97 ± 0.87) 10+2 102.5 ± 5.9 0.17 ± 0.23obtained from regression of experimental data with power law model [3]lines are calculated with MVK modelLines and points are calculated with MVK model

Synergetic and precursor effects in propane total oxidation over Cu- and Ce-based catalysts

https://biblio.ugent.be/publication/787766/file/813708.pdf

Synergetic and precursor effects in propane total oxidation over Cu- and Ce-based catalysts

Abstract

Similar works

Full text

Available Versions

Ghent University Academic Bibliography