Process for removing dissolved oxygen from an aqueous system
This invention relates to a process for removing dissolved oxygen from an aqueous system, which comprises adding a composition comprising (a) piperazine, water soluble derivatives of thereof, and mixtures thereof, and (b) a hydroxybenzene, water soluble derivatives thereof, and mixtures thereof.
1 . A process for removing dissolved oxygen from an aqueous system, which comprises adding a composition comprising:
(a) piperazine and/or a water-soluble piperazine derivative thereof as represented by the following structural formula,
wherein R 1 and R 2 are the same or different, and are selected from hydrogen, lower alkyl chains, and lower alkyl groups terminating in polar groups that impart water solubility to said lower alkyl group, and
(b) a water-soluble hydroxybenzene and/or water-soluble derivative thereof,
such that the ratio of (a) to (b) is from about 1:1 to about 100:1, to the aqueous system in amount effective to remove dissolved oxygen from the aqueous system.
2 . The process of claim 1 wherein the composition comprises 1-(2-aminoethyl) piperazine and hydroquinone.
3 . The process of claim 1 wherein the composition is injected at ambient temperature.
4 . The process of claim 1 wherein the composition is injected into an aqueous stream of a steam generating system with an operating boiler.
5 . The process of claim 4 wherein the injection point for the composition is selected from the group consisting of the pre-boiler system of the steam generator, the boiler steam drum of the steam generator, the highest-temperature feedwater heater extraction steam of the lower pressure steam turbine, the main steam header prior to the turbine, the turbine crossover piping, and satellite feeds to stream condensate lines.
6 . The process of claim 5 wherein there is mechanical deaeration.
7 . The process of claim 1 , 2 , 3 , 4 , 5 , or 6 wherein the ratio of component (a) to component (b) is from about 10:1 to about 100:1
8 . The process of claim 7 wherein dosage of the composition is from of 5 ppb to 1000 ppb.
9 . The process of claim 4 wherein there is no provision for mechanical deaeration.
10 . The process of claim 9 wherein dosage of the composition is from 5 ppm to 500 ppm.
11 . The process of claim 1 wherein the composition is injected into the water contained in a boiler in lay-up.
12 . The process of claim 11 wherein the dosage of the composition is from 5 ppm to 500 ppm.