Increasing the corrosion resistance of equipment due to the use of film-forming amines

Abstract

Results of a study of tube specimens cut from hot-water boilers show that film-forming octadecyl amine (ODA) used in the process of preservation removes deposition from the surface of the metal. An ODA film is preserved on the surface after repeated washing of the latter with hot water. The concentration of chlorides at the surface of the metal after treatment with ODA is lower than before the treatment.It is known that in the case of long-term standstill (over 7 days) of the power equipment of a cogeneration plant the equipment should be protected from standstill corrosion.The equipment with scale on the surfaces, under the layer of which corrosion processes intensify, requires protection especially urgently. In the presence of moisture standstill corrosion develops even in the absence of scale.Today the metal of power equipment is protected from standstill corrosion by various methods aimed at preventing contact between the metal and air and creating a protective film on the surface of the metal.One such method involves the use of film-forming amines, octadecylamine (ODA) in particular [1 -4]. This reagent forms a protective film on the surface of the metal, which prevents contact between the metal and aggressive media, for example, humid air. In addition, ODA possesses detergent properties [2, 3], which makes it suitable for preservation and washing-off of deposits (here and below we imply loose deposits) from power equipment stopped for a long period. At cogeneration plants this concerns hot-water boilers, which do not operate for virtually half a year.With allowance for the positive experience in the use of ODA for preservation of horizontal delivery preheaters PSG-1, -2 at power units with T-250/300-23.5 turbines, workers of TÉTs-22 of the Mosénergo Company decided to use the reagent for preservation of hot-water boilers PTVM-180. The problem with these boilers was that the deposits grew rapidly not only during service but also during dead time, when delivery water was passed through. It was expected that the use of ODA would not only reduce the corrosion rate of the tubes of hot-water boilers but also wash the surfaces from deposits (scale) for summer standstills of the heating surfaces of the boiler. In addition, the formation of a protective ODA film on the surface decreases the intensity of scale growth during operation and in the period of passage of delivery water. The positive result of preservation and washing at low amounts of deposits (up to 1000 g/m 2 ) was expected to prolong the service life of hot-water boilers and to increase the time of operation of convection bundles. This should prolong the individual lifetime of the boilers with allowance for the standstill time.In 2001 the PTVM-180 hot-water boilers of TÉTs-22 of the Mosénergo Company were preserved in a special way. The layout consisted of a batcher tank for preparing an aqueous emulsion of ODA, an intermediate vessel from which the ODA emulsion was pumped into the bottom headers of waterwall tubes of the hot-water boiler, and a pump fo...

Thermal stability of film forming amines‐based corrosion inhibitors in high temperature power plant water solutions

“…where n is an integer between 0 and 7, R1 is an unbranched aliphatic chain (such as alkyl or alkenyl) with 12-22 carbon atoms, and R2 is a short aliphatic chain (such as alkyl or alkenyl group) that usually contains 1-4 carbon atoms. The simplest FFA is ODA, n = 0, R1 = C 18 H 37 , which is also the most widespread in the energy sector 4,15,[28][29][30][31][32] and has the longest history of utilization. It belongs to the primary aliphatic amines with a saturated carbon chain.…”

“…The simplest FFA is ODA, n = 0, R1 = C 18 H 37 , which is also the most widespread in the energy sector 4,15,28–32 and has the longest history of utilization. It belongs to the primary aliphatic amines with a saturated carbon chain.…”

Stress Corrosion Cracking Behavior of TP 439 and 690 TT under Film-Forming Amine Environment

“…Presently, in the thermal power industry, the utilization of FAPs into implementing medium- and long-term boiler maintenance after shutdown has become one of the main maintenance methods [ 1 , 2 ]. The operating experiences of many thermal power plants showed that the shutdown protection of FAPs can effectively reduce the corrosion rate during the shutdown period.…”

Mass-Transfer Coefficient as an Indicator of Resin Performance: Impacts of Film-Forming Amines and Storage Time on Condensate Polishing Ion-Exchange Resins

“…Chernyshev et al 16 studied the standby corrosion prevention by ODA in a cogeneration plant. By analyzing eight hot water boiler stations, Chernyshev et al showed that an ODA layer preserved most surfaces after a long-term outage.…”