Line corrosion

Reaction of iron containing a discontinuous magnetite scale with oxygenated water, crevice corrosion, water-line attack, long-line corrosion of buried iron pipes, etc. — separable A/C type. 

Parker, N. E., Pipe Line Corrosion and Cathodic Protection A Field Manual, Gulf, Houston (1954)... 

Fig. 19.49 Overhead line corrosion detector (courtesy Corinon Ltd.)...

Where steam is used for sterilization, hospital duty, food and drug manufacturing processes, or steam humidification purposes, there generally is a reluctance (or mandated prohibition) to employ amines as a treatment for steam-condensate line corrosion protection. Clean-steam... 

Also, no specific amine-based inhibitor is generally provided to protect LP steam condensate pipework against the ravages of carbonic acid (H2C03)-induced condensate line corrosion. 

Lack of dealkalization with high alkalinity MU water NOTE Anion dealkalizers do not use acid, but also do not reduce MU water TDS and introduce additional chlorides (risk of pitting). Excessive CR line corrosion BW carryover Low cycles of concentration higher operating costs... 

Where problems develop, there is always a cause-and-effect process. In this case, as oxygen infiltrates the CR system, enhanced condensate line corrosion results (i.e., corrosion over and above the level that may be caused by the carbonic acid formed during steam condensation). This enhanced corrosion, in turn, creates the potential for further downstream corrosion debris pickup by the returning condensate and transporting this material back to the FW system. 

Today, in an era of water reuse and higher costs for premium-quality water, condensate line corrosion may be an inevitable and serious drawback when using naturally high-alkalinity water as a MU supply source. Some form of dealkalization pretreatment process generally is provided to high MU demand boiler plants but unfortunately not so often to smaller facilities. 

Oxygen infiltration coupled with (steam volatile) carbon dioxide produces enhanced condensate line corrosion. The corrosion rate of steel in the system is particularly high when both gases are present. 

Where pressure drops and oxygen infiltration can occur, the presence of both gases leads to a reaction that produces enhanced condensate line corrosion, which generates more carbon dioxide and becomes self-perpetuating ... 

The pickup, transport, and redeposition of corrosion debris and deposits can happen anywhere in steam distribution and condensate return systems and are not confined to any particular boiler plant size or pressure rating. For example, deposit pickup may occur in a superheater with redeposition taking place perhaps in a pressure reducing station, steam trap, or condensate line. The starting point for transport mechanisms is often a combination of BW carryover and condensate line corrosion. 

Steam/condensate line corrosion control. Control over steam and condensate line corrosion requires the control of oxygen, carbon dioxide (carbonic acid), and ammonia. 

Alkalinity boosters, which are vitally necessary to enable carbonate, phosphate, balanced polymer (polymer plus phosphate or chelant), and some other program types to function, are perhaps best described as conjunctional treatments, whereas oxygen scavengers, antifoams, and condensate line corrosion inhibitors are adjuncts. Programs such as phosphate-tannin mixtures are sometimes described as adjunct treatments. The chemistries and applications of various types of conjunctional treatments and adjuncts are described in this chapter. 

Low iron levels in the feed are essential to avoid damage to the electrode from iron deposition. This is achieved only by correct condensate line corrosion treatment. Polymer dispersants should be fed direct to the feed line and boiler to ensure particulate iron is effectively removed with the BD. 

It is difficult to manage the problem of high sludge production in lower pressure boilers where precipitation programs, especially carbonate conditioning, are used because it has a knock-on effect resulting in condensate line corrosion. The answer is always to install a water softener. The payback time is very short because of the reduced BD necessary as a result of decreased sludge production. 

A long-chain amine usually fed to the steam header and employed to prevent steam and condensate line corrosion by a surface-filming... 

Obrecht, Malvern F. PhD. Steam and Condensate Return Line Corrosion. Factors That Accelerate It, Retard Tt, with Emphasis on Oxygen. Heating, Piping Air Conditioning, USA, August 1964. 

ENA was recently used for remote on-line corrosion monitoring of carbon steel electrodes in a test loop of a surge water tank at a gas storage field. An experimental design and system for remote ENA and collection of electrochemical impedance spectroscopy (EIS) data (Fig. 13) have been presented elsewhere. In the gas storage field, noise measurements were compared with electrode weight loss measurements. Noise resistance (R ) was defined as... 

Electrochemical On-Line Corrosion Monitoring On-line corrosion monitoring is used to evaluate the status of equipment and piping in chemical process industries (CPI) plants. These monitoring methods are based on electrochemical techniques. To use on-line monitoring effectively, the engineer needs to understand the underlying electrochemical test methods to be employed. This section covers many of these test methods and their applications as well as a review of potential problems encountered with such test instruments and how to overcome or avoid these difficulties. 

Figures 21a and 21b are SEM micrographs of metal line corrosion defects from the top view and from the cross-sectional view. The cause was...

Fig. 21. SEM micrographs for metal line corrosion defects post-CMP cleaning from (a) a top view and (b) a cross-sectional view.

Infrared thermographic techniques can be used to identify hot spots on process equipment The camera works on the theory that the hotter the object, the higher the frequency of radiation. For off-line corrosion monitoring, horoscopes for inspecting tubes, pumps, compressors, and other equipment may be used. Spot chemical testing can indicate the... 

MORE THAN Liquid Carryover 13. The entrainment device ineffective. Condensation in down- stream lines (corrosion). Replace entrainment device. ... 

You just performed ADC on a sample of 100 defects on one lot that has been split on two CMP tools with two different copper CMP processes The first split shows about 200 defects with just one evidence of copper line corrosion. The second split shows about 2000 defects with no evidence of corrosion What process do you like better at that point What action should you take to confirm that your initial opinion is correct ... 

Keleher J, Tyre E, Her R, Babu SV, Li Y. Hydroxyl radical formation and copper line corrosion in Cu-CMP. Proceedings of the Fifth International CMP for ULSI Multilevel Interconnection Conference (CMP-MIC) Santa Clara, CA 2000 Mar 2-3.66-72. 

Corrosion rates for live brines containing CO2 or HgS are expected to be higher than those measured on dead brines in pilot-plant testing. On-line corrosion monitoring in the fleld is indicated on a case-by-case basis. Corrosion rates for emulsions are not expected to be any worse than those for crude oils containing brine. 

Flux-line corrosion, 368 Foamed glass, 218 Forming,... 

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