| abstract |
Non-gas fluid (45), such as a cellulose pulp slurry (e.g. kraft pulp), a liquid containing dissolved solids, etc. is treated with electromagnetic radiation, such as ultraviolet light from a mercury arc lamp, or a laser UV light source. The fluid to be treated (45) is introduced into the first end of a vortex, and the electromagnetic radiation (26) is introduced into the fluid from the central axis of the vortex. A reactive fluid, such as bleaching gas or liquid (21), is typically also introduced into the fluid within the vortex from the exterior of the vortex. The treatment is effected with a large surface area to volume ratio, and with a large surface renewal rate, and with the UV light passing in the opposite direction of the reactant fluid, resulting in highly efficient treatment. |