Abstract: An apparatus for injecting a treatment chemical into an oil well produced using a subsurface pump, preferably a subsurface rotary pump, is described. Crude oil is pumped upward from a subsurface oil production zone through a central production pipe in the well. A small portion of produced fluid is diverted through a by-pass line interconnecting the production pipe and the annular space of the well between the production pipe and the well casing. A venturi nozzle comprising a throat of reduced diameter is mounted in the by-pass pipe. A suction pipe interconnects a chemical storage container containing a treatment chemical with the nozzle throat. Under the action of the venturi nozzle a suction pressure is created in the nozzle throat whereby the treatment chemical is drawn through the suction pipe and mixes with the fluid in the by-pass line thereby delivering the chemical to the well annulus.

Abstract: A process for the rapid generation of chlorine dioxide under reduced pressure. A reaction column having a venturi therein and a reaction chamber in fluid communication with the nozzle of the venturi is provided. An aqueous chlorate solution and a gaseous stream of acid are introduced into the reaction chamber to react and form chlorine dioxide. A driving medium is introduced into the venturi, and the chlorine dioxide from the reaction chamber is mixed with the driving medium at the outlet of the venturi. The chlorine dioxide/driving medium mixture is passed through a reaction column. In an alternate embodiment, a chlorite solution is introduced into the reaction chamber together with the chlorate solution and the gaseous stream of acid. In a further embodiment, a chlorite solution is introduced into the reaction column after mixing of the driving medium with the chlorine dioxide.