Optimal solutions in environmental catalysis require a well-coordinated development of catalysts and of process design. This contribution is devoted to energy integrated design concepts for fuel reforming and for automotive exhaust purification. The examples presented demonstrate the importance of an innovative process design for optimal utilization of existing catalysts and show the potential of future developments.
New concepts for steam reforming through the efficient coupling of the endothermic reforming reaction with an exothermic combustion reaction are discussed in the first part. These concepts have been implemented for methanol steam reforming in a counter-current reactor with distributed side feed of burner gas and for methane steam reforming in a modular reactor with a co-current reaction section for the endothermic and the combustion reaction and attached counter-current heat exchangers. Both applications employ the so-called folded sheet reactor design, which ensures an excellent heat transfer between the reforming and combustion channels and efficient heat recovery.
A similar design solution is introduced for the apparently different case of automotive exhaust purification. The proposed concept aims at decoupling exhaust after-treatment from engine control. Its main component is a counter-current heat exchanger with integrated purification stages for HC-oxidation, NOX storage and reduction and soot filtering. A small catalytic burner at the hot end of the heat exchanger provides both heat and oxidizing or reducing agents on demand. A new soot filter design allows for safe soot filter regeneration. 相似文献
Numerical and experimental results of studying the formation of carbon clusters due to propagation of deflagration and detonation
waves in enriched acetylene-oxygen and acetylene-air mixtures are described. Experiments are performed in tubes of different
diameters (including tubes filled by a porous medium) with wide-range variations of the initial pressure and the fuel-to-oxidizer
ratio. A large variety of carbon clusters formed in different regimes of burning of the mixture is found. A typical size of
condensed carbon particles is 15–100 nm. In the case of detonation in a porous medium, the size of carbon particles is 15–45
nm; in some tests, large individual fullerene-type particles 150, 400, and 950 nm in size are formed. The fraction of condensed
carbon in the total amount of carbon in the initial mixture is found to depend on the wave type; detonation is characterized
by the minimum “yield” of condensed carbon. The amount of condensed carbon increases with increasing acetylene concentration
in the mixture and initial pressure. The size of carbon particles in the case of deflagration is greater than that in the
case of detonation. Cooling of reaction products decelerates condensation and interrupts the growth of carbon particles.
__________
Translated from Fizika Goreniya i Vzryva, Vol. 44, No. 3, pp. 81–94, May–June, 2008. 相似文献