Briquetted carbon sorbents based on the fir bark and the wood pitch

Coal tar pitch is used as a traditional binder for the production of granulated and briquetted active charcoal. Currently, there is a growing shortage of coal pitch. Hence the search for a cheaper and more available binder for briquetted active charcoal is an urgent task. In this paper, the study of the process of obtaining briquetted sorbents from the bark of Siberian fir, pyrolyzed at 450 °C, with wood pitch as a binder was carried out. The conditions for obtaining strong briquetted active wood coal with good sorption characteristics were found. The influence of preliminary steam-gas activation offir bark carbonizate on the properties of briquetted coals was investigated. It was showed that the best mass fraction of wood pitch in the initial mixture is 50 wt. %. The highest briquettes abrasion strength (up to 91 %) and good sorption characteristics were achieved at higher pressure than 20 MPa. It was shown that briquettes based on pyrolyzed bark have good adsorption characteristics for benzene (static capacity for benzene reaches 148 g/l, dynamic capacity reaches 135 g/l) and its properties were the same as the technical requirements for recovery coals ART, ART-2 and AR-3 and they can be used for solvent recovery, extraction of gasoline from natural gas and air purification from organic solvents. Isotherms of benzene adsorption were experimentally obtained. The type of isotherms is typical for porous carbon materials with a developed mesoporous structure. Briquettes obtained from pyrolyzed activated fir bark have a bulk density of560 g / dm³, a specific adsorption activity for iodine of 42 %, and the absolute adsorption capacity for iodine is slightly higher than industrial active coals of the BAU-A, BAU, DAK (bulk density 220-240 g/dm³, iodine activity - 60, 45, 30 %). Pyrolyzed activated fir bark briquettes can replace industrial active coal BAU-A in a fixed bed adsorption processes.

Keywords

Authors

References