Open AccessDevelopment of a Gas-Promoted Oil Agglomeration Process
Author(s) -
Christian Nelson,
F. Zhang,
Jan Drzymała,
M. Shen,
R. Abbott,
T.D. Wheelock
Publication year - 1997
Language(s) - English
Resource type - Reports
DOI - 10.2172/1401
Subject(s) - agitator , economies of agglomeration , agglomerate , coal , mixing (physics) , suspension (topology) , materials science , particle size , impeller , chemical engineering , chemistry , waste management , composite material , engineering , mechanical engineering , physics , mathematics , quantum mechanics , homotopy , viscosity , pure mathematics
The preliminary laboratory-scale development of a gas-promoted, oil agglomeration process for cleaning coal was carried out with scale model mixing systems in which aqueous suspensions of ultrafine coal particles were treated with a liquid hydrocarbon and a small amount of air. The resulting agglomerates were recovered by screening. During a batch agglomeration test the progress of agglomeration was monitored by observing changes in agitator torque in the case of concentrated suspensions or by observing changes in turbidity in the case of dilute suspensions. Dilute suspensions were employed for investigating the kinetics of agglomeration, whereas concentrated suspensions were used for determining parameters that characterize the process of agglomeration. A key parameter turned out to be the minimum time te required to produce compact spherical agglomerates. Other important parameters included the projected area mean particle diameter of the agglomerates recovered at the end of a test as well as the ash content and yield of agglomerates. Batch agglomeration tests were conducted with geometrically similar mixing tanks which ranged in volume from 0.346 to 11.07 liters. Each tank was enclosed to control the amount of air present. A variable speed agitator fitted with a six blade turbine impeller was used for agitation. Tests were conducted with moderately hydrophobic Pittsburgh No. 8 coal and with more hydrophobic Upper Freeport coal using either n-heptane, i-octane, or hexadecane as an agglomerant