Development of CNT reinforced Al2O3-TiO2 coatings for boiler tubes to improve hot corrosion resistance

This study examines the hot corrosion behaviour of plasma-coated T12 steel for 10 cycles of 100 h each in an industrial boiler. The coating contains CNT (carbon nanotubes) reinforced alumina-titania powders. The substrates were exposed to the boiler at 750 °C. A thermogravimetric examination was conducted to evaluate the kinetics of corrosion. Corroded samples were examined with scanning electron microscopy and x-ray diffraction analysis after the end of the corrosion cycle. This research study concludes that CNT-reinforced coatings provide better corrosion resistance than conventional alumina coatings in the boiler environment

Analysis of end crack in boiler tube

Boiler tube failures usually result in frequent forced outages, and ultimately in costly extended outages for major tubing replacement in a plant. There are several failure modes that may occur in a boiler tube, i.e. stress-corrosion cracking, pitting, water-side corrosion, fire-side corrosion, fatigue failure, overheating, dissimilar metal weld fatigue, mechanical fatigue and erosion. In this research the failure modes of boiler and its end cracks due to the dissimilar metal weld is analyzed. Hence data are collected and explored to determine the cause of failure and as a solution ceramic ferrule is suggested. The use of ceramic ferrule in boiler tube can eliminate the crack occurrence or delay the process due to thermal properties. The prevention of crack will reduce frequent maintenance and thus the cost of operation can be minimized

Power Plant Component Failures Investigation and Remedial Measures

The paper covers the reasons and remedial measures of various failed components of boiler, turbine and gene-rators in Utility Power plants of NTPC and SEB's. Boiler tube failures are mainly due to salt deposition leading to long term overheating, stress corrosion cracking and corrosion fatigue. The factors influencing the accumu-lation of salts into internal surfaces of water wall, super heater tubes have been discussed in detail. The steam turbine blades, generator retaining rings, feed water and condenser tubes have been found to suffer due to stress corrosion cracking, corrosion fatigue, pitting corrosion and crevice corrosion. Photographs of failed components and brief discussions have been given in the paper

Pencegahan Korosi Dengan Boiler Water Treatment (Bwt) Pada Ketel Uap Kapal.

This paper explained about a using of Boiler Water Treatment (BWT) as corrosion protection for boiler on ship. BWT used as addition on boiler water, which used destilat water. As experiment results, BWT used on destilat water and destilat - seawater mixed given not koagulan patch on. The simulation given not satisfied results, caused by good not equipment

Operation of a forced circulation, croloy 9 m, mercury loop to study corrosion product separation techniques

Forced circulation, Croloy 9M mercury loop designed to investigate corrosion product separation technique

SNAP-8 materials report for July - December 1965

Materials evaluation for components of SNAP-8 SYSTEM - design, development, fabrication, and testin

Investigation into high-temperature corrosion in a large-scale municipal waste-to-energy plant

High-temperature corrosion in the superheater of a large-scale waste-to-energy plant was investigated. A comparison of nickel-/iron-based alloys and austenitic stainless steel probes placed in the furnace demonstrated that temperature and particle deposition greatly influence corrosion. Nickel-based alloys performed better than the other metal alloys, though an aluminide coating further increased their corrosion resistance. Sacrificial baffles provided additional room for deposit accumulation, resulting in vigorous deposit-induced corrosion. Computational modelling (FLUENT code) was used to simulate flow characteristics and heat transfer. This study has shown that the use of aluminide coatings is a promising technique for minimising superheater corrosion in such facilities. (C) 2010 Elsevier Ltd. All rights reserved

T-111 Rankine system corrosion test loop, volume 2

For abstract, see N76-18258

Assessment of Coating Performance on Waterwalls and Superheaters in a Pulverised Fuel-Fired Power Station

Protective coatings offer one route to increase the lives of heat exchangers in pulverised fuel power plants. A range of candidate coatings have been exposed on the waterwall and superheaters of a 500 MWe UK power station unit for periods of up to ~4 years (24,880 operating hours), during which time this unit was fired on a mixture of UK and world-traded coals. Both nickel- and iron-based candidate coatings were included, applied using high velocity oxy-fuel or arc-wire process; a selection of these also had a surface sealant applied to investigate its effectiveness. Dimensional metrology was used to evaluate coating performances, with SEM/EDX examinations used to investigate the various degradation mechanisms found. Both the waterwall and superheater environments generated their characteristic corrosion damage morphologies which depended on the radial positions around the tube. Coating performances were found to depend on the initial coating quality rather than composition, and were not improved by the use of a sealant