Patent ID: 8784949

Claim:
A remote plasma process for the treatment of particulate materials comprising: the step of providing a process gas stream enriched by active species, in that an electrical gas discharge is applied to the process gas stream for the creation of a non-thermal plasma at atmospheric pressure in a plasma zone, the electrons generated in the plasma being used to generate said active species in the process gas stream; the step of superimposing high velocities upon the process gas stream enriched by active species in order to prolong the displacement distance of the active species and thus, enlarge an afterglow region of the said non-thermal plasma; the step of providing a carrier gas stream loaded with substrate particles; and the step of mixing of said process gas stream enriched by active species and said carrier gas stream in a treatment zone, wherein the substrate particle treatment in the treatment zone is spatially and temporally separated from the production of said active species such that the treatment zone is located in the afterglow of the non-thermal plasma or downstream of the plasma zone; wherein a homogenous, chemical reaction of the active species on the surface of the substrate particles takes place in said treatment zone; wherein in said treatment zone the particle loaded carrier gas stream, optionally loaded with additional gases or gas admixtures introduced at different stages along the treatment zone, is guided along an axis of the treatment zone, wherein said process gas stream enriched with active species is guided to the treatment zone from a direction essentially perpendicular to said axis, or in a conical direction, in a converging manner, and is guided to the treatment zone in an essentially circumferential and circularly symmetric manner in several planes perpendicular to said axis; wherein said process gas stream enriched with active species is guided to the treatment zone through a plurality of symmetrically arranged channels located in a plane perpendicular to said axis or in a conical direction, in a converging manner, a plurality of such planar arrangements of channels being arranged in several planes distanced from each other along said axis; wherein said plurality of symmetrically arranged channels comprises a stack of alternating high voltage electrodes and counter electrodes, and wherein in the interspace between the electrodes the process gas stream travels; and wherein the treatment zone is provided as one single through hole in said electrodes, the central axis of said hole in the electrodes defining said axis of the treatment zone.