136 4 results and discussion catalytic partial

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Unformatted text preview: ] O2 100 C3H8 99 800°C 100 99 95 92 90 82 80 Ni10C800 Ni10C900 Ni10C1000 catalyst Fig. 43 Conversion at 600, 700 and 800°C over Ni10 calcined at 800, 900 and 1000°C, 25% O2 surplus, GHSV 900dm3·h-1·g-1, TOS 240min 137 4. Results and discussion - catalytic partial oxidation of propane CO 100 H2 H2O CO2 600°C CH4 yield [%] 80 60 40 37 46 28 20 17 9 0 55 41 15 11 1 Ni10C800 CO 100 yield [%] 80 60 H2O CO2 76 61 13 10 2 Ni10C900 H2 49 4 Ni10C1000 700°C CH4 78 68 67 50 40 15 20 6 11 3 6 13 5 5 4 0 Ni10C800 CO 100 yield [%] 80 76 Ni10C900 H2 H2O CO2 90 Ni10C1000 800°C CH4 86 73 68 66 60 40 20 10 22 15 4 2 2 3 3 0 Ni10C800 Ni10C900 Ni10C1000 catalyst Fig. 44 Yield at 600, 700 and 800°C over Ni10 calcined at 800, 900 and 1000°C, 25% O2 surplus, GHSV 900dm3·h-1·g-1, TOS 240min 2 138 4. Results and discussion - catalytic partial oxidation of propane relative deactivation rate / h 15 600 700 800 5.79 9.45 4.62 3.46 1.69 1.03 0 0.06 -0.22 -3.19 -15 wt% coke / g(catalyst) 600 200 700 800 170 150 93 100 50 39 31 42 49 47 15 20 0 Ni10C800 Ni10C900 Ni10C1000 catalyst Fig. 45 Coking and deactivation at 600, 700 and 800°C over Ni10 calcined at 800, 900 and 1000°C, 25% O2 surplus, GHSV 900dm3·h-1·g-1, TOS 240 min 4. Results and discussion - catalytic partial oxidation of propane 139 The results show that under the reaction conditions the catalysts with a well crystallised structure have a superior catalytic behaviour compared to the catalyst with a poorly crystallised structure, regardless the reaction temperature. They further show that the increase in the calcination temperature from 900 to 1000°C has no significant effect on the catalytic behaviour although the catalyst calcined at 900°C is slightly more effective at 800°C and less effective at 600°C compared to the one calcined at 1000°C. Furthermore the increase in the reaction temperature from 800 to 900°C over Ni10C1000 did not result in an higher yield of CO or H2, or a better stability or coke resistance as compared to Ni10C900 at 800°C. At 900°C typical cracking products were observed, which could mean that cracking took place, possibly by homogeneous reactions. This suggestion is supp...
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This document was uploaded on 10/07/2013.

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