Open AccessSurface modified coals for enhanced catalyst dispersion and liquefaction. Quarterly report, 1996
Author(s) -
G.M.K. Abotsi
Publication year - 1996
Language(s) - English
Resource type - Reports
DOI - 10.2172/436448
Subject(s) - coal , adsorption , pulmonary surfactant , dispersion (optics) , chemistry , molybdenum , catalysis , ammonium bromide , chemical engineering , inorganic chemistry , liquefaction , dispersant , organic chemistry , biochemistry , physics , optics , engineering
The aim of this work is to enhance catalyst loading and dispersion in coal for improved liquefaction by preadsorption of surfactants onto coal. The application of surfactants to coal beneficiation and coal-water slurry preparation is well known. However, the effects of surfactants on catalyst loading and dispersion prior to coal conversion processes have not been investigated. The current work is focused on the influence of the cationic surfactant dodecyl dimethyl ethyl ammonium bromide (DDAB) and sodium dodecyl sulfate (SDS, anionic) on the surface properties of a bituminous coal and its molybdenum and iron uptake from solution. In the previous report, it was shown that molybdenum loading onto the coal was enhanced by preadsorption of DDAB. The optimum concentration of this surfactant for effective adsorption of molybdenum at the natural pH of the coal slurry has been determined to be in the 0.1 to 0.25 M range. Preadsorption of SDS onto the coal was found to increase the uptake of iron by the coal; iron loading increased with increase in the concentration of the catalyst precursor. This observation is attributed to the increase in the negative surface charge properties of the coal with increase in the concentration of the surfactant. The results of the study show that DDAB enhances the adsorption of molybdenum whereas SDS is more effective for iron loading onto Illinois No. 6 (DECS-24) coal