Date of Award
Master of Science (MS)
A rheological study was made of a liquefaction startup- feed slurry. The slurry consisted of North Dakota lignite sized to 70% less then 200 mesh and a carrier solvent of an thracene oil. The rheological behavior of the slurries, o with coal concentrations of 0 to 40% at 40 C, was shown to be Newtonian, allowing Bernoulli's equation to be used for direct calculation of pressure drop. Calculated values pre dicted the measured data within 10% for the test conditions.
The investigation used an experimental slurry loop, con sisting of a bank of pipes with nominal sizes ranging from 1 inch (2.54 cm) to 3/8 inch (0.95 cm), to determine the actu al pressure drops for the slurries. The pressure drops were found to range from 0.064 psi (4.43xlOJ dynes/cm ) for an thracene oil pumped through the 2.54 cm pipe to 11.71 psi (8.07xl05 dynes/cm2) for the 40% coal slurry pumped through a 0.95 cm pipe.
A Brookfield Rheolog viscometer was used to determine viscous behavior of samples taken from the runs. Using lin ear regression analysis, a straight line through zero was obtained for torque vs. angular velocity for each sample with correlation coefficients greater then 0.98. Viscosities of the samples ranged from 23.3 centipoise for anthra cene oil to 286.6 centipoise for the 40% coal slurry. A statistical comparision indicated that calculated and exper imentally measured pressure drops were not significantly different at the 95% confidence level.
Laudal, Dennis L., "Rheological Study of a Direct Liquefaction Feed Slurry" (1984). Theses and Dissertations. 1150.