Fundamentals of the Removal of Trace Sulfur Compounds from Natural Gas Derived Streams Via Reactive Sorption with Copper Oxide

摘要

Hydrocarbon streams derived from natural gas and oil processing are often contaminated by sulfur containing compounds, such as hydrogen sulfide and alkyl-mercaptans, which affect the quality and specifications of the product streams, pose a corrosion hazard in transfer pipelines and equipment, and conflict with health and environmental regulations. Several removal techniques have been studied and implemented in industrial purification processes ranging from gas-alkaline liquid absorption and physisorption on molecular sieve materials. Chemical reaction of sulfur molecules with copper oxide is an attractive purification strategy (especially for dilute concentrations) because the reactions are thermodynamically favorable at low temperature and the sulfur is sequestered as solid Cu-sulfur products. This study aims to elucidate the fundamentals and mechanistic details of these gas-solid reactions. Specifically, the results from this study led to semi-empirical correlations between reaction conditions (contaminant concentration, temperature, and presence of other contaminants) and the reaction rates and saturation capacities of the solid phase. Moreover, the effect of structural differences resulting from different preparation methods and starting precursors on the performance of copper oxide adsorbents in reactive sorption experiments was investigated to develop a structure-function relationship that can help in future design and tuning of adsorbent properties. A combination of thermodynamic calculations, fixed bed sorption experiments, and advanced characterization techniques are used to achieve this goal.