Coal liquefaction process streams characterization and evaluation. Solid-state NMR characterization of coal liquefaction products

摘要

This study clearly demonstrated the usefulness of liquid- and solid-state (sup 13)C- and (sup 1)H-NMR for the examination of process-derived materials from direct coal liquefaction. The techniques can provide data not directly obtainable by other methods to examine the saturation of aromatic rings and to determine the modes of hydrogen utilization during coal liquefaction. In addition, these methods can be used to infer the extent of condensation and retrograde reactions occurring in the direct coal liquefaction process. Five NMR techniques were employed. Solid-state (sup 13)C-NMR measurements were made using the Cross Polarization Magic Angle Spinning (CP/MAS) and Single Pulse (SP) techniques. Solid-state (sup 1)H-NMR measurements were made using the technique of Combined Rotation and Multiple-Pulse spectroscopy (CRAMPS). Conventional liquid-state (sup 12)C- and (sup 1)H-NMR techniques were employed as appropriate. Interpretation of the NMR data, once obtained, is relatively straightforward. Combined with other information, such as elemental analyses and process conversion data, the NMR data prove to be a powerful tool for the examination of direct coal liquefaction process-derived material. Further development and more wide-spread application of this analytical method as a process development tool is justified on the basis of these results.