Fouling and Corrosion

Cooling Wa.ter. The primary rehabihty concern is that water chemistry must be maintained in a low fouling, noncorroding regime. In addition, water flow velocity must be maintained above a certain threshold (ca 0.5 m/s in tubeside flow) to avoid fouling and corrosion. 

Silvestrini, R, Heat Exchanger Fouling and Corrosion, Chem. Eng. Prog, Dec. (1979) p. 29. 

Sneddon, A. D. and Kirkwood, D., Marine Fouling and Corrosion Interactions on Steels and Copper-Nickel Alloys, Proc. UK Corrosion 88 Conf., Inst. Corr. Sci. Tech. NACE (1988)... 

Magnesium-based additives are commonly employed to treat boiler furnace area fouling and corrosion conditions. They are injected into heavy fuel oil or other combustible material. Cerium is superior in action to magnesium salts, however, because an equivalent weight of cerium increases the melting point of the deposit more than that of magnesium. 

M. Knickrehm, E. Caballero, P. Romualdo, and J. Sandidge. Use of chlorine dioxide in a secondary recovery process to inhibit bacterial fouling and corrosion. In Proceedings Volume. NACE Corrosion 87 (San Francisco, CA, 3/9-3/13), 1987. 

As discussed under boiler feedwater treatment, boiler blowdown is required to prevent the build up of solids in the boiler that would otherwise cause fouling and corrosion in the boiler. Carry over of solids from the boiler to the steam system via tiny water droplets should also be avoided. Total dissolved solids (TDS) and silica (SiC>2), as measured by the conductivity of water, are both important to be controlled in the boiler3. Dissolved solids carried over from the boiler will be a problem to all components of the steam system. Silica is a particular problem because of its damaging effect on steam turbines, particularly the low-pressure section of steam turbines where some condensation can occur. Blowdown... 

Product treatment has also been improved (17). Bauxite treating, hot water washing, and electrostatic precipitation are some of the significant developments which have improved product quality and reduced fouling and corrosion in downstream equipment. 

High fouling and corrosion potential (2) High fouling and corrosion potential turndown is important... 

Main applications Most columns when turndown is not critical 1. Moat columns, 2. Services where tura-down is important 1. Extremely low flow conditions 2, Where leakage must be minimized 1. Capacity re-vampe where efficiency and turndown can be sacrificed 2. Highly fouling and corrosive eervices... 

Knowledge of the composition of coal ash is useful for estimating and predicting coal performance in coke making and, to a limited extent, the fouling and corrosion of heat-exchange surfaces in pulverized-coal-fired furnaces. 

Removal of EDC emulsions. A commonly occurring alkaline (pH of 12-13) process waste stream in VCM plants contains emulsions of EDC, water and inorganic solids such as calcium/iron hydroxides. The emulsion which settles between the heavier (bottom) EDC layer and the lighter (top) water layer in a tank can create deficiency in the stripping and distillation towers by causing fouling and corrosion. As indicated in Table 6.12, the amount of emulsified EDC varies from 2 to 4% and that of metal hydroxides from I to 15% by volume. 

The initial visual SEM examination of the bed sample clearly indicated agglomerated material. In this case the automated EDS-analysis could be restricted to determine the ten elements in the adhesive material of the agglomerate and the bed particles could easily be excluded from the analysis. Since it is known that high chlorine content in straw causes fouling and corrosion during normal operation of the boiler, a few point analyses were carried out in the initial examination to explore the chlorine content in the agglomerate. It turned out that there is no or very little chlorine in the adhesive material. 

Reactivity and instability of fluid can disrupt customer production by system fouling and corrosion. 

Bryers, R.W. Walchuk, O.R., "The Influence of Pyrites on Slagging in Steam Generators", International VGB Conference on Slagging, Fouling and Corrosion on Thermal Power Plants, VGB Technical Association of Large Power Plant Operators, Essen, West Germany, February 1984. 

Savlc, D. Oplk, I. Fouling and Corrosion In Steam Generators, Beograd 1980. 

Additives for high-temperature oil and coal-ash fouling and corrosion can be applied as powders or slurries. The form of the additive determines the... 

Throughout this whole process, manufacturing methods and materials requirements may be overriding considerations. Can the enhancement be produced in the material that will survive any fouling and corrosion inherent in the environment Much work needs to be done to define the fouling/corrosion characteristics of enhanced surfaces [385], Particularly, antifouling surfaces need to be developed. 

The advantages of successful lining of heat exchangers subject to fouling and corrosion may be listed as follows ... 

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