Carbon Blacks Produced by Thermal Plasma: the Influence of the Reactor Geometry on the Product Morphology

Abstract

Carbon black (CB) nanopowders were obtained by plasma decomposition of methane at various flow rates using inductively coupled thermal plasma torch system of 35 kW. Nitrogen was also introduced in some experiments along with the methane. Using a cylindrical shape reactor the obtained powders were composed mainly of spherical particles, non-uniform in terms of particles size with diameters between 30 and 150 nm. The shape and size of this reactor resulted in the presence of recirculation areas enabling the formation of large CB particles and other secondary volatile compounds. Changing the reactor to a conical geometry resulted in the production of CB powders showing a crystalline and flake-like morphology made of sheets having 6-16 graphitic planes. The conical shape avoids the presence of recirculation areas and promotes the formation of a uniform powder morphology throughout the reactor.

Carbon Nano-Flakes Produced by an Inductively Coupled Thermal Plasma System for Catalyst Applications

“…Close examination of TEM images (Fig. 7b,d) show a stacking with the same number of graphene planes (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16) as in the case of powders produced without nitrogen addition. It can be concluded that the addition of nitrogen along with methane during the production process does not affect the morphology of the material.…”

“…1. Such geometry provides a gradual gas expansion from the torch to the reactor minimizing both recirculation areas and sudden quenching of the gas [15,16]. A 4 mm annular gap between the ICP plasma torch body Fig.…”

“…The produced powders collected from different parts of the conical reactor show a uniform morphology [16], which was analyzed using scanning and transmission electron microscopy (SEM and TEM). The particles show a flake-like morphology (Figs.…”

“…The lower values were obtained for the samples in which the presence of organic volatile compounds was observed. It is believed that such organic compounds act as a glue causing the agglomeration of the carbon nanoflakes, and results in a decrease in the value of the specific surface area [16].…”

Design-Oriented Modelling of Different Quenching Solutions in Induction Plasma Synthesis of Copper Nanoparticles

“…The use of a reaction chamber with a conical top region has been investigated by Pristavita et al [30] and by Colombo et al [13], concluding that a finer control of the flow pattern (loss of nanoparticles to the walls) and nanoparticle properties (size) can be achieved thanks to its shape with respect to the cylindrical case. Furthermore, it was shown that the injection of a shroud gas in synergy with the chamber geometry allows to confine the nucleation region away from the walls and to reduce the nanoparticle deposition on them, resulting in higher process yield [13].…”