Tanks and piping

Steel is an acceptable material of constmction for handling solutions of up to 50% NaOH below 40°C. Above 40°C the steel corrosion rate increases rapidly and iron is picked up in the solution. Materials for handling 50% NaOH are lined steel for tank cars and lined or unlined steel for tanks and piping. 

Spray. In spray-on appHcations the reactive iagredients are impingement mixed at the spray head. Thickness of the foam is controlled by the amount appHed per unit area and additional coats are used if greater than 2.5 cm (1.0 ia.) thickness is required. This method is commonly used for coating iadustrial roofs or iasulatiag tanks and pipes. 

Centrifugal casting is used to produce water softener tanks and pipe by saturating a reinforcement with thermosetting resin within a mold that is then rotated at high speed to consoHdate the laminate before curing. 

Water plays a primary role in corrosion of the metal walls of tanks and pipes (17), and increases the tendency for high speed pumps to produce wear particles and to exhibit shortened life. Formation of corrosion products can be controlled by addition of corrosion inhibitors, a mandatory additive in military fuels. However, corrosion inhibitors may also degrade other fuel properties and adversely affect ground filtration equipment. Thus they are not generally acceptable in commercial fuels where rigorous attention is given to clean and dry fuels upon aircraft fueling. 

Polyurethane. Polyurethanes (pu) are predominantly thermosets. The preparation processes for polyurethane foams have several steps (see Urethane polymers) and many variations that lead to products of widely differing properties. Polyurethane foams can have quite low thermal conductivity values, among the lowest of all types of thermal insulation, and have replaced polystyrene and glass fiber as insulation in refrigeration. The sprayed-on foam can be appHed to walls, roofs, tanks, and pipes, and between walls or surfacing materials directly. The slabs can be used as insulation in the usual ways. 

Carbon disulfide is normally stored and handled in mild steel equipment. Tanks and pipes are usually made from steel. Valves are typically cast-steel bodies with chrome steel trim. Lead is sometimes used, particularly for pressure reUef disks. Copper and copper alloys are attacked by carbon disulfide and must be avoided. Carbon disulfide Hquid and vapor become very corrosive to iron and steel at temperatures above about 250°C. High chromium stainless steels, glass, and ceramics maybe suitable at elevated temperatures. 

Bisphenol F epoxy resins are used in high-soHds-high-build systems such as tank and pipe linings, industrial floors, road and bridge deck toppings, stmctural adhesives, grouts, coatings, and electrical varnishes. Bisphenol F epoxy resins are manufactured in Europe and Japan. 

API RP 1632, Cathodic Protection of Underground Petroleum Storage Tanks and Piping Systems, 3rd ed.. May 1996. 

After adjustment, the tank and pipe/soil potentials have to be checked annually and recorded. The results of the measurements are the basis of the maintenance process. If the check measurements differ from the values established by the control, the cause must be determined and the defect remedied. 

Used mainly for building insulation and as a laminate. Also employed in cold water tanks and pipes. 

The effect of pH on the corrosion of zinc has already been mentioned (p. 4.170). In the range of pH values from 5 -5 to 12, zinc is quite stable, and since most natural waters come within this range little difficulty is encountered in respect of pH. The pH does, however, affect the scale-forming properties of hard water (see Section 2.3 for a discussion of the Langelier index). If the pH is below the value at which the water is in equilibrium with calcium carbonate, the calcium carbonate will tend to dissolve rather than form a scale. The same effect is produced in the presence of considerable amounts of carbon dioxide, which also favours the dissolution of calcium carbonate. In addition, it is important to note that small amounts of metallic impurities (particularly copper) in the water can cause quite severe corrosion, and as little as 0-05 p.p.m. of copper in a domestic water system can be a source of considerable trouble with galvanised tanks and pipes. 

Types of wood and their chemical resistance and physical characteristics are reviewed, including examples showing the manufacture of typical tank and pipe construction. In-service case histories are included. While this coverage takes you from the Forest to the plants making acetic acid, that is beyond the need for most users it is hoped that the reader becomes aware that this product family is the only MOC for several CPI applications and is a competitive choice over some quite exotic materials, e.g., titanium, in others. 

Rubber, particularly in the form of linings for tanks and pipes, has been extensively used in the chemical industry for many years. Natural rubber is most commonly used, because of its good resistance to acids (except concentrated nitric) and alkalies. It is unsuitable for use with most organic solvents. 

U.S. EPA, Straight Talk on Tanks Leak Detection Methods for Petroleum Underground Storage Tanks and Piping, EPA-510-B-05-001, U.S. EPA, Washington, 2005. 

Limited aperture releases are conceptualized in Figure 4-2. For these releases material is ejected from holes and cracks in tanks and pipes, leaks in flanges, valves, and pumps, and severed or ruptured pipes. Relief systems, designed to prevent the overpressuring of tanks and process vessels, are also potential sources of released material. 

Vessel, tank and piping supports in fire hazardous zones. 

Rigid polyurethane foams account for 80% of MDI use, especially for construction (about half of this use), refrigeration, packaging, and tank and pipe insulation. Other uses are reaction-injection molding (RIM) applications (13%) and cast elastomers (2%). 

Other factors are important, too, Zirconia has a nasty tendency to settle out rock-hard in tanks and pipes, and besides the material loss, clean-up costs are severe, Ceria will settle eventually, but always is soft and easy to re-suspend. Ferric oxide (red rouge) is an excellent, but slow polish, and a bad pollutant due to its irreversible staining quality. White rouge is a very slow polish, and is rarely seen in use today. 

Sulfur readily attacks copper and its alloys, bronze and brass, to form copper sulfide, CuS. Elemental sulfur, mercaptan sulfur, or hydrogen sulfide can all attack copper bearing parts. Fuel storage tanks and piping systems can contain copper heating coils, and cooling coils, as well as brass or bronze valves and fittings. These parts are all susceptible to sulfur-initiated corrosion. 

Compatibility of ethanol with tank and piping materials such as carbon steel, stainless steel, and Fiberglas is good. Zinc linings and epoxy linings are not stable in ethanol systems and are not recommended for use. Also, epoxy adhesives and resins are dissolved by ethanol. Teflon and nylon are compatible elastomers. In... 

Corrosion in metallic components occurs when pure metals and their alloys form stable compounds with the process fluid by chemical reaction or electrochemical processes resulting in surface wastage. Appreciable corrosion can be permitted for tanks and piping if anticipated and allowed for in design thickness, but essentially no corrosion can be permitted in fine mesh wire screens, orifice plates and other items in which small changes in dimensions are critical. Rates of corrosion can be heavily affected by temperature changes and whilst a material of construction may be suitable at one temperature, it may not be appropriate for use at a higher temperature with the same process fluid. 

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