Study of protective properties of DEFENDER corrosion inhibitors in the wastewater of oil fields
This post presents the results of research of protective properties of hydrocarbon-soluble polyfunctional corrosion inhibitors of DEFENDER series, developed and produced by the Himipex Oil Company. At present time these inhibitors are successfully used to protect against corrosion of equipment in the oil and gas industry and differ from a number of inhibitors of similar purpose by greater versatility.
For example, corrosion inhibitors DEFENDER besides high protective properties, also exhibit significant washing and detergent-dispersant effect, allowing not only to reliably protect the equipment, tanks and pipes against corrosion, but also to clear the working surfaces from asphaltene-resin-paraffin deposits (ARPD), mineral and mechanical deposition.
DEFENDER series corrosion inhibitors have been developed by us specifically, in order to increase the protective effect of oil and gas equipment, tanks and industrial pipelines, during their exploitation and conservation in downtime. We brought the protective film of our DEFENDER corrosion inhibitors on the inner surface of the pipeline section filling it with pre-prepared 3% solution of the inhibitor in the industrial oil. After the pipeline treatment with inhibitor solution for 20 hours, pipeline was freed from solution. During the contact with the inhibited industrial oil solution, protective layer of adsorbed inhibitor molecules and industrial oil was forming on the working surface of the pipeline. After mentioned actions, the section of the pipeline was put into operation for pumping waste water of oil fields with total mineralization of 170 g/dm3 and a concentration of hydrogen sulfide about 500 ppm. The flow rate of the process fluid in the pipeline was 1.2 m/sec.
Evaluation of the protective effect of inhibited oil films in static and dynamic conditions was carried out by polarization resistance method.
It is known that industrial oil without inhibitors poorly protects the steel from corrosion, which is particularly manifested in dynamic conditions, when the liquid flow violates the integrity of the adsorbed film of oil and quickly washes out it. With that the corrosion protection is actually absent. The opposite actions are observed in films of oil with the addition of 3% DEFENDER corrosion inhibitor.
These films have a stable high protective properties which do not diminish within 30 days, under static as well as dynamic conditions. Moreover, the protective effect of DEFENDER corrosioninhibitors under dynamic conditions even increases. Such kinetics of the corrosion process is typical for high-performance protective compositions, and explained by the formation on the metal surface protective layer of the solid colloidal structure of "sandwich" type.