Film-Forming Amines in Steam/Water Cycles: structure, properties, and influence on corrosion and deposition processes

This work evaluates the effect of film-forming amines (FFA) on the acidic stress-corrosion cracking (SCC) resistance of NiCrMoV turbine steel. Contact angle measurements show an increased hydrophobicity of the surface when coating the steel with oleyl propylene diamine (OLDA). According to potentiodynamic measurements and post-mortem scanning electron microscopy (SEM) analysis, anodic dissolution and hydrogen embrittlement still occur when the steel is FFA coated. In situ constant extension rate testing (CERT) in acidic aqueous environment at elevated temperature of FFA-coated steel shows a ductility gain compared to non-coated steel, explained by a decrease in both corrosion rate and hydrogen uptake.

Effect of Film-Forming Amines on the Acidic Stress-Corrosion Cracking Resistance of Steam Turbine Steel

Principles used in the development of modern computation codes for calculating erosion-corrosion of power equipment are considered. Specific features of their practical applications aimed at preventing, revealing, and eliminating erosion-corrosion thinning of the metal of elements used in the units of power stations are analyzed. Results obtained from using the domestically developed computation code RAMEK for operating power units are presented and prospects for implementing it in designing new power units of nuclear power stations are determined.

Principles of Development and Specific Features Relating to Practical Application of Software for Solving Problems Connected with Erosion-Corrosion of Metal in Power Engineering

Damageability of heat transfer surfaces of waste heat recovery steam generators (HRSG) of combined- cycle plants (CCP) can be reduced due to an increase in the quality of make-up and feed water, the use of phosphate-alkaline or amino compound water chemistry (WC), and improved chemical quality control of the heat carrier and make-up water preparation techniques Temporary quality standards for the heat medium developed by the All-Russia Thermal Engineering institute (VTI) for CCP power units are presented in comparison with the IAPWS standards; preferences for the choice of a WC type for some power units commissioned in Russia in the first decade of this century are shown; and operational data on the quality of feed, boiler water, and steam for two large CCP-450 and CCP-425 power units are given The state and prospects for the development of chemical-technological monitoring systems and CCP water treatment plants are noted Estimability of some CCP diagnostic parameters by measuring specific electric conductivity and pH is shown An extensive bibliography on this topic is given

Water-Chemistry and Its Utility Systems in CCP Power Units (Review)

The reliability and effectiveness of the operation of combined-cycle power plants (CCPP) depend largely on the erosion-corrosion resistance of the power system equipment, including heat recovery steam generators (HRSG). Foreign and domestic experience shows that one of the most widespread failure modes is wear of the low-pressure evaporator tube system (LPETS), resulting in premature reduction of metal thickness and sudden fracture of low-pressure evaporator (LPE) components of CCPP heat recovery steam generators. A lists of the primary factors that affect the occurrence and development of flow-accelerated corrosion is provided. Data is presented on the dependence of the erosion-corrosion rate of various metals in water on the temperature and a velocity of the working medium. Problems that arise in the LPEs of the heat recovery steam generators Kirishi State District Power Plant and paths for resolution are examined.

Methods to Combat the Causes of Damage to the Steam-Forming Pipes of the Low-Pressure Circuit in CCPP Heat Recovery Steam Generators

We present the results from an analysis of damageability and determination of dominating mechanisms through which thinning occurs to the metal of elements used in the tube system of heat recovery boilers used as part of combined-cycle plants during operation and during their outages. Results obtained from putting in use a technology for making the tubes of such boilers more resistant to erosion-corrosion wear with the aid of film-forming amines are also presented. Measures are proposed on extending the service life of the tube system of heat recovery boilers used as part of combined-cycle plants and operating under the conditions of single- and two-phase flows.

A. V. Mikhailov

Papers

Extending the erosion-corrosion service life of the tube system of heat-recovery boilers used as part of combined-cycle plants