The Study Of Methane Partial Oxidation To Syngas Over Monolithic Foam Nickel Catalyst

The catalytic partial oxidation of methane(POM) to syngas has the advantages of low energy consumption, high selectivities of CO and H2 and with a H2/CO ratio close to 2, which can be directly used as the feed of methanol or Fischer-Tropsch synthesis. As POM is a reaction under high temperature and high space velocity, sintering and losing of Ni and carbon deposition are obvious. The key factor of realizing industrialization is to design and prepare the catalyst with high catalytic activity, high stability and long life.In this thesis, the effects of CH4/O2 ratio, space velocity, reaction temperature, and H/D ratio on monolithic foam nickel catalyst activity were measured. The catalysts were characterized to provide useful information for catalyst modification.The results indicate that CH4/O2 ratio affects catalyst capability in evidence, higher CH4/O2 ratios are in favor of CH4 conversions and selectivities of CO and H2, but CO2 selectivities drops. Bed temperature affects catalyst capability obviously, higher reaction temperature is in favor of CH4 conversions and selectivities of CO and H2, but CO2 selectivities falls. Higher space velocities affect catalyst capability slightly, higher space velocities benefit CH4 conversions and selectivities of CO and H2, but CO2 falls, as space velocity increase to some extent, the methane conversions and selectivities of CO and H2 decline to steady. Higher H/D ratios help to increase the conversions of CH4 and to improve selectivities of CO and H2, while CO2 selectivities drops, as H/D ratios increase to some extent, CH4 conversions and CO selectivities decline to steady. Process conditions being optimized are as follows: reaction temperature is 950℃, space velocity is 1.35×105h-1, CH4/O2 ratio is 1.5, H/D ratio is 0.75. After reacting 8 hours in theses conditions, CH4 conversions is 90%, CO selectivities is 90%, H2 selectivity is 69%, CO2 selectivity is 11%.In order to examine perspective of partial oxidation of nature gas to syngas, this research tested the capability of nature gas partial oxidation over monolithic foam nickel catalyst. The results point out that C2H6 and C3H8 in nature gas slightly reduce CH4 conversion, but selectivities of H2, CO and CO2 are almost the same, therefore the catalyst has a good future of partial oxidation of nature gas to syngas. Under the same condition as methane partial oxidation, the reaction results are as follows: CH4 conversions is 88%, CO selectivity is 90%, H2 selectivity is 68%, CO2 selectivity is 12%.H2-TPD indicates that it is difficult for H2 to desorb from catalyst. It is estimated that the reaction between hydrogen and oxygen being absorbed is the primary approach to produce H2O, and it maybe lead to the lower H2 selectivity.