| Abstract: | The role of vapor liquid equilibrium in the coal liquefaction process and its effect on the process kinetics were studied. Available experimental data were analyzed by inclusion of vapor-liquid equilibrium in an existing model to study its effect on the kinetics. The analysis showed that due to liquid vaporization, a significant increase in the slurry residence time occurs. In the range of operating variables investigated, the actual slurry residence time was observed to be higher by a factor of 1.14 to 1.41. Model simulations for some typical operating conditions (717-737 K, 13.8-20.7 MPa) showed the wt. fraction of liquid vaporized to be in the range of 0.1 to 0.3. This is seen to be in agreement with published data on the volatility of typical coal liquids. This study has shown that consideration of vapor-liquid equilibrium in the kinetics and design of coal liquefaction process can be of importance, especially at high temperatures, where vaporization would be significant. |
