Determination of Solid Impurities in Mesophase Pitch by a Filtration Model of a Binary-Mixture Cake

The present study was conducted with the aim of optimizing the filtration of mesophase pitch by determining solid impurities which are several microns in particle diameter and in very low concentration. The concentration and mean size of solid impurities in mesophase pitch were estimated by an experiment using filter aids and a filtration model of a binary-mixture cake. The filtration model consists of a porosity and specific filtration resistance estimation equations for a binary mixture of solid particles. As a result, mean diameter of solid impurities of 9.2 μm and a concentration of 690 ppm were obtained. These values closely agreed with the values obtained by using various filter aids. It was confirmed that the model can be used to estimate the concentration and mean size of solid impurities contained in mesophase pitch. Though the present experiment was carried out to determine solid impurities in mesophase pitch, the filtration model of a binary-mixture cake employed in the present study is considered applicable widely to other operations involving body filtration.