Catalyst monitoring

G. B. Fisher and co-workers. The Kole of Ceria in Automotive Exhaust Catalysis and OBD-II Catalyst Monitoring, SAE 931034, Society of Automotive Engineers, Warrendale, Pa., 1993. 

El Fallah, J., Boujani, S., Dexpert, H., Kiennemann, A., Majerus, J., Touret, O., Villain, F., and Le Normand, F. 1994. Redox processes on pure ceria and on Rh/ Ce02 catalyst monitored by x-ray absorption (fast acquisition mode)../. Phys. Chem. 98 5522-33. 

Special Feature I. Ethylene-Styrene Interpolymers Technologies, Products and Markets . The Metallocene and Single Site Catalyst Monitor, The Catalyst Group, Spring House, PA (December 2000). 

Rupprechter G (2001) Surface vibrational spectroscopy from ultrahigh vacuum to atmospheric pressure Adsorption and reactions on single crystals and nanoparticle model catalysts monitored by sum frequency generation spectroscopy. Phys Chem Chem Phys 3 4621... 

Figure 7. Impact of sulfur on the OBD-II catalyst monitor in a production Transitional Lx)w Emission Vehicle (TLEV).

Figure 10.16. Schematic representation of the operating principle of an on-board catalyst monitoring system.

Figure 10.18. Stepwise reversibility experiments (i.e. effect on catalyst monitor switch ratio) on the same...

A second sensor downstream of the catalyst, first introduced to meet the OBD diagnostic requirement such as catalyst monitoring (Section 7.15.1.7), is now also used to correct the aging behavior of the front sensor (Fig. 17.15.4). Protected by the catalyst against poisoning and high amounts of unreacted gas mixture, this rear sensor features a very stable signal characteristic over life. All new lambda control systems of recent years are based on this two-sensor concept. 

Since the equipment used in XRF technique including radioisotope source is portable, the energy dispersive XRF spectrometers are used in various divergent fields like that in the metal industry, in gold mines, in oilfields for oil analysis (to determine sulfur in petroleum products and residual catalysts, monitor additives in lubricating oils, analyze regular wear metal in lubricants... 

Industrial applications of tracers are also numerous. The fate of a catalyst in a chemical plant can be followed by incorporating a radioactive tracer in the catalyst, such as Ir in a Pt-Ir catalyst. Monitoring the activity of the Ir makes it possible to determine the rate at which the catalyst is being carried away and to which parts of the plant it is being carried. 

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