Helical Screw Rheometer: An Advance in Instrumentation for Direct Coal Liquefaction

摘要

Sandia has developed and tested the novel Helical Screw Rheometer to study gelling and vacuum bottoms in direct liquefaction processes. This device, which is essentially an extruder, has inherent advantages over conventional rheometers because it eliminates flow rate and torque measurements. Theory and representative data are presented. Although the HSR was conceived to study slurry gelling, it has widespread applications - primarily because conventional rheometers are not well-suited for high-pressure and high-temperature uses. In particular, a suitable rheometer is lacking for on-line applications in petro-chemical and polymer processing plants, where viscosities are very sensitive to slight variations in composition and process conditions. The HSR is suitable for on-line uses because it has the simplicity of a rotational rheometer and the range of a capillary rheometer. Also, the HSR can handle yield stress fluids; because the flight forces the fluid to flow, the fluid cannot set and plug the rheometer. 11 references, 7 figures. (ERA citation 09:047295)