Scale, boiler

Phosphorus is also important in the production of steels, phosphor bronze, and many other products. Trisodium phosphate is important as a cleaning agent, as a water softener, and for preventing boiler scale and corrosion of pipes and boiler tubes. 

Prevention of Soil Crusting. Acid-based fertilizers such as Unocal s N/Furic (a mixture of urea with sulfuric acid), acidic polymers such as FMC s Spersal (a poly(maleic acid) derivative originally developed to treat boiler scale) (58), the anionic polyacrylamides described previously, as weU as lower molecular weight analogues such as Cytec s Aerotil L Soil Conditioner, have all been used successfully in at least some circumstances to prevent the formation of soil cmsts. It is difficult to prove benefits in the laboratory, and field tests may give variable results depending on local weather conditions. 

Note 1 B. Kamp [Z. tech. Fhysik, 12, 30 (1931)] skews tke effect of increased porosity in decreasing tkermal conductivity of boiler scale. Partridge [University of Michigan, Eng. Research Bull., 15, 1930] has published a 170-page treatise on Formation and Properties of Boiler Scale. 

Erosion can be caused by small particles not visible to the human eye, like dissolved minerals in hard water. Larger solids like sand, boiler scale, and rust can also cause serious erosion inside the pump. 

Kesselstein, m. boiler scale compass brick, -ablagerung, /. deposit(ion) of boiler scale, -beseitigung, /. removal of boiler scale, -be-seitigungsmittel, n, (boiler) scale remover, disincrustant. -bilder, -bildner, m. (boiler) scale former, -bildung, /. (boiler) scale formation, incrustation. -gegenmittel, n. boiler compound, disincrustant. -kruste, /. incrustation of boiler scale. -losemittel, -losungamittel, n. (boiler) scale solvent, dis ... 

Pfannen-probe,/. Metal.) ladle teat, -stein, m. pan scale boiler scale, -werk, m. salt works, -ziegel, m. pantile. 

Salz-schicht, /. layer of salt, -schmelze,/. salt melt, fused salt, -see, /. salt lake, -siede-pfanne, /. salt pan. -sieder, m. salt boiler, salt maker, -siederei, /. salt making salt works, -sole, -soole, f. brine, salt water salt spring, -speck, m. bacon, -stein, m. boiler scale rock salt, -stoffwechsel, m. salt metabolism, -ton, m. salt clay, saliferous clay. -wa(a)ge,/. brine gage, salinometer. 

This is primarily engaged in analysis of boiler water treatment matters and involves on-site studies of various problems and the chemical examination of corrosion products, boiler scales, etc. It can also carry out certain types of metallurgical, fuel and inorganic analysis. Normal wet methods of analysis coupled with a visible ultraviolet and atomic absorption spectrophotometer are used for a wide range of analytical applications. Equipment in use by the engineering insurers providing these services can include an ion chromatograph, spectrometer equipment, atomic... 

The thermal conductivity of an average boiler scale is 2.2 (W/m K) and that of complex silicate scales is 0.2-0.23 (W/m K). Since the furnace peak wall flux can be over 300,000 (W/m ) it may readily be seen that a small thickness of scale can raise the metal temperature into the creep region, resulting in very expensive repairs. 

After the temporary hardness has been removed, any calcium and magnesium which remains is still capable of forming a scum with soap, and can also react to form boiler scale. This is called the permanent hardness. 

Localized pre-boiler scale and corrosion debris deposits. Combination of New phosphate, iron, copper, and silica deposition Old re-deposited debris Transport of Fe, Cu, Ni, Zn, Cr oxides to HP boiler section, leading to deposition, fouling, and possible tube failures Transport of minerals and debris including malachite, ammonium carbamate, basic ferric ammonium carbonate Precipitation in FW line of phosphates, iron, and silicates... 

Apart from calcium and magnesium bicarbonates, most natural sources of MU water commonly contain some small amounts of silica and other dissolved minerals, salts, and contaminants. Under a wide variety of operational circumstances, every one of these common materials may contribute to complex boiler scales and deposits, especially the silicates. Thus, it is necessary to ensure that water chemistries are properly balanced and controlled. 

Sulfate, chlorides, and phosphates are common contaminants and contribute to boiler scales and deposits. 

Boiler scales and corrosion product deposits also may form from the thermal breakdown of treatment chemicals. Breakdown products of chemicals such as sulfite, amines, hydrazine, and chelants often are steam-volatile, and subsequent reactions may produce corrosion debris that forms deposits and causes blockages. This problem typically occurs when chemical treatments selected for use are applied under unsuitable operating conditions (as when the boilers are highly rated or raise steam at particularly high operating pressure or temperature). 

A laboratory analysis of most boiler scales and other types of deposits typically shows the presence of a mixture of several minerals and other... 

The example of chicken breath was inspired by the article, From chicken breath to the killer lakes of Cameroon uniting seven interesting phenomena with a single chemical underpinning by Ron DeLorenzo, Journal of Chemical Education, 2001, 78(2), 191. The article also discusses boiler scale, the way that carbon dioxide partitions between hzzy drink and the supernatant gases (see p. 165), and stalactites and stalagmites. 

Sources. From manufacture of refractory crucibles, fire bricks, magnesia cements, boiler scale compounds... 

J. D. Dana showed that fluorine occurs in the lime of corals (162). Dr. G. Wilson of Edinburgh and J. G. Forchhammer both detected it directly in sea water from the Sound near Copenhagen, and the latter demonstrated it still more easily in the boiler scale from Transatlantic steamers (98). 

In addition to the ability of polyphosphates to bond cations they also possess the important property of hindering the formation of large crystallites of CaCO i and of solid boiler scale, even when present at very small concentrations (239). This property, which is used in the threshold or in-noculation process, is based on the bonding or adsorption of polyphosphate chains on the surface of the crystal nucleus. These then hinder its further growth or aggregation. The effectiveness of detergents to which polyphosphates have been added must also be related to their adsorption on the... 

The thin-section methods of the petrologist may be used for artificial specimens which are in the form of large aggregates—specimens of such materials as refractories, bricks, and boiler scales. Instead of powdering them and using immersion methods, it is possible to grind thin sections and examine them. When it is simply a question of distinguishing between a few possible constituents of known characteristics, this is a useful method. But in unfamiliar systems the powder method is likely to be more useful for identification purposes the principal function of the thin-section method in such circumstances is to provide information on the distribution, orientation, or size of the crystals of the different constituents. 

Boiler scale, consisting of insoluble metal carbonates, such as CaC03 and MgC03, forms when hard water is heated. 

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