Patent ID: 9699879
Date: 2017-07-04
CPC Classifications: H05H

Claim:
1. An apparatus for sintering green pellets to make proppant particles, the apparatus comprising: a vessel having an overflow disposed in a first end, an underflow disposed in a second end, a middle portion having a circular cross-section disposed between the first end and the second end, and a tangential inlet proximate to the first end such that a gas from the tangential inlet flows along a vortex path from the first end to the second end of the vessel; a first electrode extending through the overflow and a second electrode extending through the underflow, wherein both electrodes are at least partially disposed within the vessel, spaced apart from one another, and axially aligned with one another along a central axis of the vessel from the first end to the second end; one or more feed tubes extending through the overflow proximate to the first electrode; and wherein the electrodes are used to create an open electrical arc that sinters or partially sinters the green pellets from the one or more feed tubes in a selected temperature range to form the proppant particles as the green pellets pass between the electrical arc and the gas flowing in the vortex path and exit the underflow.