A Novel Multiple Plasma Jet Tangentially Mixed Reactor: Design and Carbon Black Production

In this paper, a new multiple plasma jet tangentially mixed reactor (MPJ-TMR) is proposed. The impact of varying tangent circle diameters on the mixing process is investigated through CFD simulation. The MPJ-TMR has been preliminarily applied to high-conductive carbon black (HCCB) preparation. The results show that the MPJ-TMR with a tangent circle diameter d_c/d_in = 0 is directed to form the "counter-flow recirculation zone", which impedes mixing between plasma jets and cold fluids. For the MPJ-TMR with a tangent circle diameter d_c/d_in > 0, the intensity of the "counter-flow recirculation zone" weakens and disappears as the tangent circle diameter increases. The eccentric impact flow drives the fluid to spiral around the central axis. So that a spiral vortex structure is formed to enhance the mixing. Among them, the MPJ-TMR with a tangent circle diameter d_c/d_in = 0.5 exhibits the best mixing efficiency due to its highest local circumferential velocity and axial vortex flux, resulting in good entrainment between plasma jets and cold fluids. Therefore, the MPJ-TMR with a tangent circle diameter d_c/d_in = 0.5 is applied to prepare carbon black. The resulting products show a rich branched chain structure with over 90% of the primary particle size distributed within the range of 10–20 nm. The physicochemical indices DBP Absorption, IAN and resistivity of HCCB are very close to that of acetylene carbon black. The reactor demonstrates excellent product uniformity.