Topsoe

H. Topsoe, B. S. Clausen, N. Topsoe, andj. Hyldtoft, Symposium on the Mechanism of HD S / HDN Reactions, Vol. 38, No. 3, Division of Petroleum Chemistry, Preprints, American Chemical Society, Chicago, lU., July 1993. 

Hafnium and Hafnium Compounds, 73 Haifa Chemical Co. Ltd., 251 Haifa Chemical Company Ltd., 177 Haldia Petrochemicals Ltd., 171 Haldor Topsoe A/S, 154 Hall Chemical Company, The, 231... 

A silver-gauze catalyst is still used in some older processes that operate at a relatively higher temperature (about 500°C). New processes use an iron-molyhdenum oxide catalyst. Chromium or cohalt oxides are sometimes used to dope the catalyst. The oxidation reaction is exothermic and occurs at approximately 400-425 °C and atmospheric pressure. Excess air is used to keep the methanol air ratio helow the explosion limits. Figure 5-6 shows the Haldor Topsoe iron-molyhdenum oxide catalyzed process. 

Figure 5-6. The Haldor Topsoe and Nippon Kasel process for producing formaldehyde (1) blower, (2) heat exchanger, (3) reactor, (4) steam boiler, (5) absorber, (6,7) coolers, (8) Incinerator, (9) heat recovery, (10) methanol evaporator, (11) boiler feed water.

Figure 10.10. Turnover frequency of the S02 catalytic oxidation [mol S02 (converted)/mol V2Os/s] vs. the working electrode polarization for the VK-58 catalyst (Haldor Topsoe A/S) at 400°C.12 Reproduced by permission of the Electrochemical Society.

A related approach is to interface an industrial promoted catalyst with a solid electrolyte (Fig. 12.2). In this case the bulk of the commercial catalyst must be conductive. This concept has been already demonstrated for the case of NH3 synthesis on Fe-based promoted commercial catalysts (BASF S6-10 RED)16 and for the case of SO2 oxidation on V2O5-K2S2O7 based catalysts (Haldor-Topsoe VK-58).17... 

The Cu/ZnO system is very dynamic. The morphology of the Cu particles responds immediately to a change in reduction potential of the gas mixture above it. EXAFS studies suggest that the change in morphology is associated vith the extent that the metal particles vet the underlying support [B.S. Clausen, J. Schiotz, L. Gr4-bffik, C.V. Ovesen, K.W. Jacobsen, J.K. Norskov and H. Topsoe, Top. Catal. 1 (1994)... 

The contribution of different crystal planes to the overall surface area of the particle can thus be calculated and is shown in Fig. 8.12(b). The results have been included in a dynamical micro-kinetic model of the methanol synthesis, yielding a better description of kinetic measurements on working catalysts [C.V. Ovesen, B.S. Clausen, J. Schiotz, P. Stoltze, H. Topsoe and J.K. Norskov, J. Catal. 168 (1997) 133]. 

Figure 8.20. An ammonia plant capable of producing totally 2x1350 tons ammonia per day over 2x150 tons of catalyst. The immense size of the reactors is illustrated by the size of the people indicated by the arrow. (Courtesy of Haldor Topsoe AS.)...

This procedure reflects today s technology where, typically, a two- or three-bed reactor is used. Recent investigations by Jacobsen et al. [C.J.H. Jacobsen, S. Dahl, A. Boisen, B.S. Clausen, H. Topsoe, A. Logadottir and J.K. Norskov, J. Catal. 205 (2002)... 

Owing largely to research over the last twenty years, the sulfided C0-M0/AI2O3 system is one of the best-characterized industrial catalysts [H. Topsoe, B.S. Clausen and F.E. Massoth, Hydrotreating Catalysis (1996), Springer-Verlag, Berlin]. A combination of methods, such as Mbssbauer spectroscopy, EXAFS, XPS, and infrared spectroscopy, has led to a picture in which the active site of such a catalyst is known in almost atomic detail. 

Table 10.S. Composition of flue gas from coal-fired power plants [from N.-Y. Topsoe, CaTTech 1 (1997) 125],...

The combined approach of removing both the sulfur and the NOx from the flue gas is called SNOX (Haldor Topsoe A/S) or DESONOX (Degussa). An example of the setup for this process is shown in Fig. 10.11, where 99% of the NOx is converted in the SCR reactor and the SO2 is converted into sulfuric acid. 

Figure lO.n. Schematic diagram of the SNOX process used to remove both SO2 and NOx from the flue gas. (Courtesy of Haldor Topsoe A/S.)... 

Figure 10.15. Catalytic cycle for the SCR process over acidic V -OH sites and redox V=0 sites. [Adapted from N.-Y. Topsoe, Science 26S (1994) 1217.]...

Figure 10.16. NO conversion and ammonia slip as a function of the NH3/NO ratio in the presence of O2 and H2O over a V203/Ti02 catalyst at 623 K. The lines represent the model based on reactions (9)-(14) and the parameters in Tab. 10.7. [Adapted from).A. Dumesic, N.-Y. Topsoe, H. Topsoe, Y. Chen, and T. Slabiak, J. Catal. 163 (1996) 409.]...

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