A Study of Dissolution Rate in Hydro-liquefaction of Coal

Abstract

For the analysis of dissolution rate in coal liquefaction, continuous flow perfect-mixing-type reactor was used. The experiments were carried out by using Morwell brown coal at temperatures, 393-450°C under the pressure of 150 kg/cm²·G. And the equation of dissolution rate was introduced in consideration of the effects of hydrogen in equilibrium with coal slurry and of hydrogen donor ability of solvent. The over-all dissolution rate constant is expressed by the following equation:
k =(C_Coal0 - C_Coal) / C_Coal · (C_Hydrogen + A) · θ
where C_Coal0 and C_Coal are the concentrations of feed and of remaining coal after the reaction, respectively; C_Hydrogen is the concentration of hydrogen in equilibrium with coal slurry, A is the term of hydrogen donor ability of the solvent and θ( h ) is the residence time. All concentrations are expressed by maf coal %.
The temperature dependence of k for Morwell brown coal was expressed as in k=-14.7 x 10³(1/T) + 20.9, and activation energy of dissolution was 29.3 kcal/g-mol. In these experiments, the value A was 9.90, and it was found that the effect of A was considerably large in comparison with CHydrogen.