317,047. Soc. de Recherches et d'Exploitations PetrolifÞres. Aug. 9, 1928, [Convention date]. Carbon. - In the activation of carbonaceous materials suspended in gases, the gases are circulated in counter-flow so that the activation gases emerge relatively cold from the activation retorts. The retorts may be heated internally or externally or both, and the operation may be continuous or discontinuous according as the activation and heating are carried out simultaneously or alternately. The activating gases employed include water vapour, carbon dioxide, chlorine and combustion gases; they may be diluted with neutral gases or gases having no activating action such as nitrogen, hydrogen, water gas, carbon monoxide and used activation gases. The retorts may be heated by producer gas, gases from the activation, mazout, crude oil, pulverized coal, or by electricity. The carbonaceous material reduced to the desired size is fed through a funnel 1, Fig. 1, to a mixer A supplied with activating gas through a pipe 2 and with neutral gas through a pipe 3. The gaseous suspension passes through a pipe 4 to the activating retort 3 and thence to separators C', C<2> through a pipe 5. The separators may consist of centritugal apparatus followed if desired by apparatus for filtration or for liquid or electrostatic precipitation. The separated active carbon is collected at points 6, 7.. The gases leave through a pipe. 8 and may be returned to the mixer A through a pipe 3<1> by a fan 9. The excess gas, when combustible, is led through pipe 10 to the retort for use in heating, or is rejected through pipe 11 to the chimney. The activation apparatus consists, in one form, Figs. 2 and 3, of a heat insulated furnace 12 containing four activation retorts, each formed of an outer tube 16 closed at its upper end and an inner tube 17. The gaseous suspension is fed through pipe 4 to the outer annular spaces of the retorts up which it passes and is withdrawn through the tube 17 to pipe 5, heat exchange taking place between the entering and leaving gases. The retorts are heated externally by combustion gases from burners 13, the gases escaping through flue 15. Baffles may be provided within the furnace to provide a more effective circulation of the heating gases. The tubes 16, 17 may be of steel or cast iron in the lower zone of the furnace and of refractory material in the upper zone. The tube 17 may be provided with inner and outer ribs 19. The retorts may alternatively be externally heated electrically, the combustible gases from the activation being then used for other purposes. In a further form, Fig. 4, adapted for internal heating, the retort comprises a cylindrical thick-walled heat insulated body 20 of refractory material provided with an inner tube 21. The gaseous suspension enters through tube 4 and passes up outside tube 21, through a combustion chamber 23 when activation takes place, the activation being completed in the upper annular space 24. The material leaves through tube 21, giving up its heat, and passes through tube 5 to the separators. Heating is obtained by burners 22 provided in chamber 23. Heating may alternatively . be effected by burning part of the material to be activated by introducing a small amount of air through orifices arranged in the same manner as the burners 22. The operation may also be discontinuous, the retort being first heated to high temperature by gases produced in chamber 23 and withdrawn through a pipe 26. The air for the combustion may be introduced through a pipe 27 opening into pipe 4 so that it is preheated. The mixture of activating gases and carbonaceous material is then introduced through pipe 4 until the temperature of the walls is sufficiently lowered, the heating step being then resumed. Simultaneous internal and external heating may be obtained by providing the retorts with suitable outer walls and disposing a number of them in a furnace of the kind employed in the previous form, or by employing supplementary electric or other external heating. In other forms, the retorts may be vertically or obliquely arranged, and several retorts may be connected together so as to carry out the treatment in several phases.