Development of a gas-promoted oil agglomeration process. Quarterly technical progress report, October 1--December 31, 1995

The overall purpose of this research project is to carry out the preliminary laboratory-scale development of a gas-promoted, oil agglomeration process for cleaning coal using model mixing systems. Specific objectives include determining the nature of the gas promotion mechanism, the effects of hydrodynamic factors and key parameters on process performance, and a suitable basis for size scale-up of the mixing system. An investigation of the phenomena which occur during the oil agglomeration of coal particle suspensions showed that the process of agglomeration involves several step which can be identified by changes in agitator torque and by application of optical microscopy. During one of these steps, aggregation of hydrophobic particles and microflocs takes place on the surface of gas bubbles dispersed in the suspension with the result that large flocs or flakes are produced which subsequently evolve into agglomerates. The time required to produce spherical agglomerates appears to be a function of the power input per unit volume with the time decreasing as the power input increases