Experimental and Discussion

After coating, the titer-plates are inserted into the reactor to test their activity. The reaction conditions were held constant in the following experiments. The reactor was heated to 475 °C and held at a pressure of 0.2 bar (g). The heat exchanger was operated at 50 °C, and the throughput for a single well was adjusted to 1 ml min-1, resulting in a total space velocity of 9000 h 1. The residence time in the wells was 0.4 s. 

An under-stoichiometric mixture of methane and oxygen (2 1) was diluted with 70% nitrogen, preheated and distributed within the distribution module and continuously delivered to the single wells. For the catalytic combustion of methane, a number of parallel and consecutive reactions occur [57]. During the tests mostly carbon dioxide was obtained according to the formula  

Cullis and Keene [83] have also found that under low-temperature conditions the conversion of methane is nearly completely due to the formation of these total oxidation products. 

Catalysts prepared by the wash-coating method were first used to check the reproduction of the measured values. For this reason, six elementary metal salts (platinum, zirconium, molybdenum, nickel, silver, and rhodium) were dissolved and impregnated onto a titer-plate. The catalysts were pre-reduced inside the reactor with 5% hydrogen in 95% nitrogen at 250 °C. The results were recorded first before the pre-reduction and then after the pre-reduction. The repeated measurements indicated good reproducibility in both cases. The conversion of methane with the rhodium catalyst is better after the pre-reduction. Methane conversion after 18 h runtime was still stable. 

To check if fluidic or thermal cross-talk exists, the same six metal catalysts were coated in six rows on one titer-plate. Active catalysts were positioned on neighboring wells with less active catalysts (Fig. 4.15). The result was that the two active rows (platinum and rhodium) did not influence the neighbouring less-active rows (zirconium and silver). Thus, cross-talk was not observed. In the next test, elementary, binary and ternary mixtures of the same metal catalysts were examined. Every mixture was deposited on four different wells to check for reproducibility (Fig. 4.16). Except for some of the ternary mixtures, the results were well-reproduced and were consistent with the known well activity of rhodium (row 1) and the mixture of rhodium and platinum (row 5) that had the highest activity. 

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The alkyl radicals initially generated will usually react exclusively with oxygen. Other reactions such as decomposition, disproportionation, isomerization, recombination and reaction with the fuel will only compete when the partial pressure of oxygen is low or the temperature high (ca. 450 °C). The nature of their reaction with oxygen, particularly in the temperature range 250—400 °C, has led to considerable experimentation and discussion. 

This method is widely used to measure the distance between sites on a macromolecule, and has been the subject of considerable experimentation and discussion [17-19],... 

The result of a long process of experimentation and discussion was the remarkable but inescapable conclusion that in the nature of things no composition of another velocity with the velocity of... 

In a conformational analysis, chemists want to know which conformations are significantly populated, but beyond that there are various facts they can hope to learn experimentally and discuss about each conformation ... 

To sum up, we may say that two types of departures from the normal behavior of a viscous liquid have been observed experimentally and discussed theoretically. Neither relate, as a rule, to pure liquids, which exhibit Newtonian behavior predominately, but to solutions or sols. The departures may be described as follows ... 

Examples of 2PS spectra measured experimentally and discussion on the vibrational and rotational temperatures... 

When the heat transfer is less than the maximum, there are two possible modes of steady state flame propagation—one corresponds to a low value of the flame velocity and the other to a high value. Spalding has studied these modes experimentally and discussed them from a quasi-theoretical point of view. 

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