Storage tanks corrosion rate

Corrosion. Copper-base alloys are seriously corroded by sodium thiosulfate (22) and ammonium thiosulfate [7783-18-8] (23). Corrosion rates exceed 10 kg/(m yr) at 100°C. High siUcon cast iron has reasonable corrosion resistance to thiosulfates, with a corrosion rate <4.4 kg/(m yr)) at 100°C. The preferred material of constmction for pumps, piping, reactors, and storage tanks is austenitic stainless steels such as 304, 316, or Alloy 20. The corrosion rate for stainless steels is <440 g/(m yr) at 100°C (see also Corrosion and corrosion control). 

The V-03 is the equipment number. The type of equipment is a horizontal storage tank. It is used to store methanoi. The capacity is 20,000 gal (76 m3) and the size is 11 ft (3.35 m) in diameter by 31 ft (9.5 m) long. The tank is to be made of carbon steel and will not be insulated. It should be built to withstand a pressure of 10 psig (1.8 kg / cm2). Any vessel with a rating of under 15 psig (2 kg / cm2) is not considered a pressure vessel. No information is given on temperature or corrosion allowances because neither of these factors presents any special problem. The rate of corrosion... 

Many attempts to control corrosion in sulfuric acid vessels are made to preserve product purity. As an example, electrolytic-grade sulfuric acid must not have over 50 ppm of iron. It is almost impossible to store acid for any reasonable time in a bare or unprotected steel tank and maintain this level. Iron pick-up in a storage vessel containing 94% sulfuric acid increased from 110 to 280 ppm during 28 days storage [16]. It can be said that the iron content may increase at rates of 5 to 20 ppm day of unprotected storage tanks. In order to maintain a low iron content in acid, it is necessary to use some sort of corrosion control in storage vessels. 

The most common use of anodic protection has been to control corrosion of sulfuric acid storage tanks made of carbon steel, with a particular emphasis to reduce iron pick-up. Table 2 shows that anodic protection drastically decreased the amount of iron pick-up, as compared to that in the unprotected tank [17]. In addition to the iron content, the corrosion rate of anodically protected steel in 94% acid with a mean temperature of 10 °C was 10.5 times lower than that of unprotected steel. These data (Table 3) [17] indicate that anodic protection is an efficient means of controlling the corrosion of steel storage... 

Storage of contaminated ethyl acetate in mild steel containers is likely to result in corrosion of the tank and some acceleration in the rate of hydrolysis. 

C. Storage and Transfer. Concentrated sulfuric acid up to about 99% H2SO4 can be handled in ordinary ferrous-metal equipment. The rate of corrosion reaches a minimum at about 96%. In 93% acid at about 50°C, the rate is 0.6-0.65 mm yr For a 10-year life, a corrosion allowance of 6.5 mm should be specified. Anodic protection can cut the rate of corrosion approximately in half and extend tank life, but it is not often used by chlor-alkali producers. Above 99% and 50°C, the corrosion rate of carbon steel is greater than 1.5mmyr , and stainless steel is often specified. 

Weast, R. C. (1954). A study of. some variables which influence the corrosion rate of galvanized steel hot water storage tanks. Proc. Am. Gas. Assoc. 34, 863-867. 

The principal feed to the HLW concentrator is the HLW stream from the contamination solvent extraction cycle. This typically contains about 2.5 M HNO3, 3-9 g FPs L L and 400-1200 Ci L"k and generates heat at the rate of 2.6 W L"L Additional feed may be intermediate-level waste concentrate and nitric acid evaporator bottoms. The HLW concentrator is usually operated at subatmospheric pressure and made of corrosion-resistant material such as titanium to extend life and minimize maintenance. Wastes are concentrated as far as possible without appreciable solid formation. If solids other than FPs are absent, a concentration of about 90 g FPs per liter can be obtained. Products are contaminated nitric acid overhead, slightly under 2.5 M, and evaporator bottoms, about 7 M in HNO3. Because evaporator bottoms self-heat at a rate up to 1 °C mn", the evaporator and the bottoms storage tanks must be provided with reliable cooling (Benedict, Pigford, and Levi, 1981,489). 

In large storage tanks (30 x 10 x 10 m) used for spent fuel rods from nuclear power plants, which are lined with stainless steel (no further details given) and filled with demineralised water, the corrosion rate after many years of service was determined [130]. Under the conditions 20°C 5 °C, pH 5 1, 0.1 mg/1 oxygen as well as 0.1 mg/1 chloride ions a total container weight loss of 150 mg/a was found by spectral analysis, which corresponds to a corrosion rate of 0.01 pm/a. This means absolutely negligible corrosion attack. Information since only Fe, Cr and Ni, and no Mo were found in the spectral analytical data, the described stainless steel involved was assumed to be an 18/8 CrNi steel. 

The corrosion rates for uniform surface corrosion are always less than 0.002 mm/a (0,08 mpy), so that this type of corrosion can be neglected. However, for molybdenum-free steel grades, there is a risk of crevice corrosion in most cases. Both types of steel are also insensitive to damp gases containing H2S that occur in some parts of the plant. Damp chlorine vapors, which arise if there is insufficient ventilation in the vicinity of chlorine storage tanks, can also lead to pitting corrosion of the 316-type steels at locations where such vapors can collect. 

Corrosion-resistant resins for construction are experiencing an annual growth rate greater than 18%, due to environmental rules and regulations. These resins are used in process equipment and pollution control apparatus, such as ducts, storage tanks, tubing, pipes, hoods, and related items for industrial applications. In the corrosion-resistant equipment area... 

The liquid storage tank shown in Fig. E2.13 has two inlet streams with mass flow rates w and W2 and an exit stream with flow rate 1V3. The cylindrical tank is 2.5 m tall and 2 m in diameter. The liquid has a density of 800 kg/m. Normal operating procedure is to All the tank until the liquid level reaches a nominal value of 1.75 m using constant flow rates w = 120 kg/min, W2 = 100 kg/min, and wn, = 200 kg/min. At that point, inlet flow rate wi is adjusted so that the level remains constant. However, on this particular day, corrosion of the tank has opened up a hole in the wall at a height of 1 m, producing... 

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