Remote non-thermal atmospheric plasma treatment of temperature sensitive particulate materials and apparatus therefore

A device for carrying out a process for the treatment of particulate materials, said device comprising:

• a plurality of high voltage electrodes and alternating parallel counter electrodes for the generation of a non-thermal plasma at atmospheric pressure in an interspace between said electrodes,
• wherein a treatment zone is provided along a central axis as one single through hole in said plurality of electrodes, said treatment zone being essentially in the form of a channel along said central axis, and wherein said central axis is essentially perpendicular to planes defined by said plurality of electrodes,
• wherein the interspace comprises a plurality of symmetrically arranged channels located in a plane perpendicular to said central axis or in a conical direction, a plurality of such planar arrangements of channels being arranged in several planes distanced from each other along said central axis, said process for the treatment of particulate materials comprising:
• a step of providing a process gas stream enriched by active species, in that an electrical as discharge is applied in said interspace to the process gas stream before entering the treatment zone 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;
• a step of superimposing high velocities upon the process gas stream enriched by active species in order to prolong the displacement distance of active species and thus, enlarge the afterglow region of the said atmospheric plasma;
• a step of providing a carrier gas stream loaded with substrate particles guided through said treatment zone along said central axis;
• and
• a step of mixing of said process gas stream enriched by active species and said carrier gas stream in said treatment zone,
• wherein the substrate particle treatment in the treatment zone is spatially and temporally separated from the production of said active species in said interspace such that the treatment zone is located in the afterglow of the non-thermal plasma or downstream of said interspace;
• 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 said central axis,
• wherein said process gas stream enriched with active species is guided to the treatment zone through said interspace from a direction essentially perpendicular to said central 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 central axis;
• wherein said process gas stream enriched with active species is guided to the treatment zone through said plurality of symmetrically arranged channels.