At all temperatures over these two catalysts the o2

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Unformatted text preview: 00. Here complete O2 conversion was only observed at 800°C and it decreased with decreasing reaction temperature. The C3H8 conversion was always lower than those observed for the other catalysts and decreased also with ppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppp 4. Results and discussion - catalytic partial oxidation of propane 135 ppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppp decreasing reaction temperature (Fig. 43). Over all catalysts the yield of CO decreased with decreasing reaction temperature (Fig. 44). The lowest yield of CO was always observed for the catalyst calcined at 800°C. Over Ni10C900 as well as Ni10C1000 the yield of H2 was almost the same at 700°C and 800°C (around 70%), but decreased at 600°C (around 45%). Over Ni10C800 a similar behaviour was observed but at lower H2 yield. The yield of CO2 increased over all catalysts with decreasing reaction temperature. No clear trends of the yield of H2O could be noticed, its value was relatively high for the catalyst Ni10C1000 at 800°C (22%). The yield of CO, H2, H2O, CH4 and CO2 over Ni10C1000 at 900°C (not depicted), were 90, 72, 13, 8% and 2%, respectively. C2H4, C2H6 and C3H6 were only observed at 800 and 900°C over the catalysts Ni10C800 and Ni10C1000 with yields ≤ 1% of each compound. For the catalysts Ni10C900 and Ni10C1000 catalyst deactivation and coking generally decreased with the increasing reaction temperature and was higher for Ni10C1000 than for Ni10C900 (Fig. 45). No deactivation and lower coking (15%) was observed for Ni10C1000 at 900°C. Ni10C800 showed an increasing catalyst deactivation with increasing reaction temperature and higher coking than the other catalysts. The apparent catalyst activation at 600°C should have the same reason as discussed in more detail above. 136 4. Results and discussion - catalytic partial oxidation of propane conversion [%] O2 C3H8 99 100 600°C 99 79 80 69 59 60 46 40 Ni10C800 O2 C3H8 conversion [%] 100 Ni10C900 700°C 100 98 91 Ni10C1000 87 88 Ni10C900 Ni10C1000 80 70 60 Ni10C800 conversion [%...
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This document was uploaded on 10/07/2013.

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