Improved Chemical Treatment Program for Optimum Corrosion Control in a Combined Cycle Power Plant

摘要

The prevention of corrosion in steam generatingrnsystems is vital to efficient and long-term reliability.rnOxygen pitting can rapidly lead to failures while formationrnof metal oxides from corrosion results in deposition,rncausing reduced heat transfer rates and/orrnunder-deposit corrosion. The limited deposit tolerancernof high pressure boilers requires that a corrosion inhibitionrnprogram perform optimally.rnThe importance of corrosion mitigation in steamrngenerating systems is widely known and well documentedrnin numerous technical papers, articles, reportsrnand journals. Corrosion of system components cost thernutility industry millions of dollars in repair and maintenancernwhile reducing revenue due to down time.rnAdditionally, the transportation and eventual builduprnof metal oxide corrosion products on heat transfer surfacesrnreduces the heat rate and drives up the cost perrnmegawatt produced. Thermal stresses associated withrnthese deposits can compromise the integrity of boilerrntube metal affecting the micrograin structure and leadingrnto failure.rnHigh pressure boilers are extremely susceptible tornwaterside problems due to dissolved oxygen and internalrncorrosion and deposition. As boiler pressuresrnincrease, heat and mass transfer throughout the boilerrnbecome more critical even though the majority of thesernhigh pressure boiler systems are found in installationsrnthat employ sophisticated pretreatment equipment suchrnas demmeralization, desaiination/evaporation, RO,rnelectrodialysis and ultrafiltration - all designed tornproduce extremely high purity water for makeup to thernsteam generating system.rnMethyl ethyl ketoxime (MEKO) is a proprietaryrnpatented volatile oxygen scavenger/metal passivatorrnwhich was first used commercially to treat a 2600 psigrnutility boiler ir, 1988. Since then, it has been used successfullyrnin over 150 high pressure power and cogenerationrn(IPP) installations.rnMEKO has demonstrated its superiority in controllingrnoxygen corrosion, passivating metal surfaces,rnreducing metal oxide transport and actually removingrndeposit weight density loadings from boiler tubes,rneliminating the cost associated with chemical cleaning.rnThis paper will present information associatedrnwith the application of MEKO, a specific amine blend,rnand a formulated phosphate/polymer product in arnGulf Coast combined cycle power plant heat recoveryrnsteam generator (HRSC).