Methane conversion in the simulated countercurrent moving-bed chromatographic reactor.

摘要

As the world depletes its supply of fossil fuels such as oil and coal, making efficient use of vast, remote reserves of natural gas (mostly methane) has been extensively studied recently. Converting natural gas economically to valuable, liquid products would be highly beneficial. This work investigates the conversion of methane to ethane and ethylene (CA which are precursors to many valuable liquid fuels and chemicals, and the direct conversion of methane into methanol. Both of these reactions are low per pass conversion reactions, which makes them economically unattractive. A novel separative reactor, the Simulated Countercurrent Moving bed Chromatographic Reactor (SCMCR) has been found to increase the conversion of low conversion reactions. This reactor is applied to these methane conversion reactions to dramatically improve the conversion, and therefore the yield of the, desired products.; Phase I of this research concentrates on the further development and optimization of the SCMCR for the oxidative coupling of methane (OCM) to C ₂. Many improvements were made in the reactor design in order to improve (1) efficiency of design, (2) reliability of the data collected, and (3) performance of the OCM in the SCMCR. Experiments on the reaction section and separation section were conducted to determine the best catalyst and adsorbent to use in the SCMCR. Experiments verified the optimal operating parameters such as the switching time and CH₄/O₂ makeup ratio predicted in an SCMCR model. Experimentally, the SCMCR gave C₂ yields of 45%, approximately double the 20%–25% reported in traditional catalytic reactors, and in reasonable agreement with the model.; Phase II of the research investigates the application of the SCMCR to the direct partial oxidation of methane to methanol. A new system had to be designed and built to accommodate the high pressures necessary (~100 atmospheres) to achieve high methanol selectivity. Experiments were carried out to determine suitable reactor and adsorbent sections. Than a suitable combination of reactor and adsorbent sections was implemented in the SCMCR. Experiments again gave large improvements in methanol yield, from 5% in conventional reactors to near 25% in the SCMCR.