Date of Award

7-17-1991

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Chemical Engineering

Abstract

This thesis reports the equilibrium characteristics of the vapor and liquid phases of hydro-treated anthracene oil under conditions commonly used in coal liquefaction. These data should be useful in coal liquefaction studies and pro cess designs.

The experiments were performed using the UND EERC's Hot Charge, Time Sample, Batch Autoclave System. Samples could be taken at desired temperatures and pressures with minimal disturbance to the system. The automated system allowed samples to be taken in a consistent manner.

Tests were conducted in temperature and pressure ranges of 300 to 440 °C and 2000 to 4000 psia, respectively. Sam pling intervals were 20 °C for temperature and 500 psi for pressure.

Samples were analyzed to determine the fraction of the solvent present in the vapor state. The fraction of sol vent in the vapor phase increased with increasing tempera ture. This is the expected effect of temperature, since increased temperature typically increases the vapor pres sure of a solvent. The fraction of solvent in the vapor phase remained nearly constant as pressure was increased through the addition of nitrogen gas. The solvent behaved as could be expected, since changing the total pressure in this manner should have very little effect on the vapor pressure of a solvent.

The percentages of light, middle, and heavy oils pres ent in the samples were also determined. The data show that the percentage of heavy oils in the liquid phase was nearly constant over the range of conditions tested. These data did not follow the expected trend for an increase in temperature and therefore vapor fraction. The liquid phase of the system would be expected to become richer in heavy oils as the vapor fraction increases, since the lighter, more volatile oils are the first to vaporize.

The results suggest, instead, that thermal cracking of the heavier organics may have occurred, since an increase in the percent heavy oils in the liquid phase did not coin cide with increased vapor fraction. Additional analyses showed that for all of the autoclave runs, the mass per centage of heavy oils in the solvent decreased during test ing. This provides further evidence that cracking of the solvent occurred.

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