Antisolvent-Induced Agglomeration of Mineral Matter in Coal-Derived Liquids. Final Report

摘要

The influence of many of the variables associated with anti-solvent induced agglomeration of mineral matter in coal derived liquids was observed by an indirect x-ray photographic measurement of sedimentation. The primary variables were anti-solvent type, dose, combinations of anti-solvent and gas, anti-solvent addition rate, and mixing properties. Also, the properties of the coal derived liquids have a great influence on the ash agglomeration and sedimentation. A correlation is proposed which relates the effectiveness of various anti-solvents, as evidenced by an increase in the initial settling rate, with their carbon/hydrogen ratio and solubility parameter. The advantage of this correlation over those proposed earlier is that it involves more fundamental and readily available properties of the anti-solvent. Anti-solvent mixture effects can be predicted by using molar weighted averages of the carbon/hydrogen ratio and solubility parameter. Mixing speed is a more important variable than mixing time. Sequential mixing, i.e., a short period of high speed followed by a longer period of low speed mixing produces an increase in the initial settling rate. Mathematical models are proposed to explain the effects of mixing. It was found that increased preasphaltene content of the coal derived liquids greatly increased the efficiency of the anti-solvents for agglomeration and sedimentation. In addition to using the x-ray technique to evaluate vertical sedimentation of ash particles, the experimental apparatus was modified to permit inclined batch sedimentation experiments. As expected, the sedimentation rate greatly increased in the inclined settler. The experimental data compared well with existing theories. (ERA citation 06:019672)