Abstract: The invention relates to the field of mixing plants, in particular, to devices for mixing a powder reagent with a flow of a liquid medium. The specified technical result is produced due to the development of an apparatus for injection of a powder reagent into the flow of a petroleum product, which comprises: a cylindrical mixing chamber, an inlet for feeding a powder reagent, an outlet to remove the powder reagent mixed with the petroleum product; a powder reagent introducer with an outlet connected to the inlet of the mixing chamber through a flow restriction device; a pump for feeding the mixture from the mixing chamber to the oil pipeline, in which the specified at least one inlet for feeding petroleum products are tangential, an inlet for feeding the reagent and the outlet to remove the mixture are axial.