Sonic injection into a PGM Peirce-Smith converter: CFD modelling and industrial trials
DK Chibwe, G Akdogan, GA Bezuidenhout, JPT Kapusta, S Bradshaw, JJ Eksteen
Peirce-Smith converters (PSCs) are extensively used in the copper, nickel,
and platinum group metals industries. The typical converting operation
involves lateral purging of air into molten matte through a bank of
tuyeres. This blowing operation occurs at low pressure from the blowers,
resulting in a bubbling regime that is considered inefficient from both a
process and an energy utilization perspective. Inherent drawbacks also
include recurrent tuyere blockage, tuyere punching, and low oxygen
efficiency.
Western Platinum embarked on a full-scale industrial evaluation of
generating a jetting regime by using sonic injection. Prior to industrialscale
tests, a numerical assessment to ascertain the feasibility of
implementing sonic injection into a PSC was conducted. The work included
flow characterization at high-pressure injection achieving sonic velocity at
the tuyere exit. The 2D and 3D simulations of the three-phase system were
carried out using the volume of fluid method together with the RKE
turbulence model to account for the multiphase and turbulent nature of
the flow.
This paper discusses the key findings in understanding plume
extension, velocity distribution, shear wall stress analysis, and phase
distribution characteristics in the system. Plant trials are also discussed
with reference to the commercial aspects of a full-scale implementation of
sonic injection in the smelter.
Keywords: Peirce-Smith converter, sonic injection, CFD modelling.