Über die Vergasung von Reaktorgraphit mit Kohlendioxid und Wasserdampf

Abstract

The gasification of nuclear graphite with CO 2 in the pressure range of 0·1 to 1 atm CO 2 and 0 to 0·7 atm CO at temperatures between 980 and 1120°C was investigated in a batch operated recirculation reactor. A rate equation of the Langmuir-Hinshelwood type was not suited to represent the experimental results, because small CO pressures were found to have a relatively stronger inhibiting effect than high CO pressures. The same graphite was used to study the CO 2-C reaction with small partial pressures of CO 2 ranging from 0·4 to 2 mm Hg in the presence of 0–2 mm Hg CO in helium as a carrier in a continuously operated recirculation reactor at a total pressure of 1 atm. The CO inhibition was considerably stronger than calculated from the rate equation which was determined in the high pressure range. Moreover, the inhibition of a definite CO content decreased with increasing partial pressure of CO 2. The measurements of the rates of the H 2O-graphite reaction covered a pressure range of 0·2 to 0·8 mm Hg H 2O in helium as a carrier at temperatures of 940–1030°C. H 2O was found to be 17 times more reactive than CO 2 at 1000°C. Both products H 2 and CO (0–0·8 mm Hg) inhibit the reaction. In agreement with the results of the CO 2-graphite reaction the extent of the observed inhibiting effect was much stronger than it could be expected from studies of other authors at H 2O pressures of about 1 atm.