Salts water

As an example of the effect that corrosion can have on connnercial industries, consider the corrosive effects of salt water on a seagoing vessel. Corrosion can drastically affect a ship s perfonnance and fiiel consumption over a period of time. As the hull of a steel boat becomes corroded and fouled by marine growths, the... 

At this point the system has throe phases (CUSO4 CuS04,Hj0 HjO vapour) and the number of components is two (anhydrous salt water). Hence by the phase rule, F + F = C + 2, t.e., 3+F = 2 + 2, or F=l. The system is consequently univariant, in other words, only one variable, e.g., temperature, need be fixed to define the system completely the pressure of water vapour in equilibrium with CUSO4 and CuS04,Hj0 should be constant at constant temperature. 

Silicon is important to plant and animal life. Diatoms in both fresh and salt water extract Silica from the water to build their cell walls. Silica is present in the ashes of plants and in the human skeleton. Silicon is an important ingredient in steel silicon carbide is one of the most important abrasives and has been used in lasers to produce coherent light of 4560 A. 

Pure vanadium is a bright white metal, and is soft and duchle. It has good corrosion resistance to alkalis, sulfuric and hydrochloric acid, and salt water, but the metal oxidizes readily above 660oC. 

Titanium has potential use in desalination plants for converting sea water into fresh water. The metal has excellent resistance to sea water and is used for propeller shafts, rigging, and other parts of ships exposed to salt water. A titanium anode coated with platinum has been used to provide cathodic protection from corrosion by salt water. 

NOTE In order to make this as painless as possible, please observe the following recommendations 1) Keep the mixing bowl temperature as close to OC or less as possible 2) Keep the Hypochlorite solution as it is being added as close to OC or less as possible 3) After half the Hypochlorite solution has been added, place a plastic bag with 50-1 OOg ice/salt/water mix into the bowl to help keep temperatures low (use this instead of directly adding ice to the reactants, which adds a considerable volume of water making the process less volumetric ally efficient) 4) Purchase an 81b bag of ice ahead of time ... 

The Bathythermograph. The thermistor sensing probe of a disposable bathythermograph is coated with parylene. This instmment is used to chart the ocean water temperature as a function of depth. Parylene provides the needed insulation resistance and is thin and uniform enough to permit a rapid and accurate response to the temperature of the surrounding salt water (64). 

Fig. 6. A comparison of k a values (51). Represented are 1, stirred bioreactor using water, = 0.02 m/s, kj a (eq. 16) 2, stirred bioreactor using water, t 3 = 0.04 m/s, kj a (eq. 16) 3, bubble column using water, kj a (eq. 18) 4, stirred bioreactor using salt water, = 0.02 m/s, kj a (eq. 17) 5, stirred bioreactor using salt water, = 0.04 m/s, kj a (eq. 17) and 6, bubble column using salt water (noncoalescing).

The chemical analysis of waste fuels also demonstrates that the wood-based fuels contain virtually no sulfur and Htde nitrogen. Unless the hog fuel contains bark from logs previously stored ia salt-water, the chlorine content is very modest to nonmeasurable. 

Corrosion occurs when the metallic iron in DRI is wetted with fresh or salt water and reacts with oxygen from air to form mst, Ee(OH)2- The corrosion reactions continue as long as water is present. Because water evaporates at approximately 100°C, corrosion reactions have a low temperature limit even though the reactions are exothermic. Small amounts of hydrogen may be generated when DRI reacts with water. However, this poses no safety problem as long as proper ventilation is provided. 

Allowing DRI to become wet does not necessatily cause it to overheat. When large pdes of DRI are wetted with rain, the corrosion reactions are limited to the outer surface area of the pde and the resultant heat from the corrosion reactions is dissipated into the atmosphere. However, if water penetrates into the pde from the bottom, or if wet DRI is covered with dry DRI, the heat from corrosion reactions can budd up inside the pde to the point where rapid reoxidation begins. Corrosion occurs significantly faster with salt water than with fresh water. DRI saturated with water can cause steam explosions if it is batch charged into an electric arc furnace. 

G lv nic Corrosion. Galvanic corrosion is an electrochemical process with four fundamental requirements (/) an anode (magnesium), 2) a cathode (steel, brass, or graphite component), (J) direct anode to cathode electrical contact, and (4) an electrolyte bridge at the anode and cathode interface, eg, salt water bridging the adjacent surfaces of steel and magnesium components. If any one of these is lacking, the process does not occur (133,134). 

K. N. Reichek, K. J. Clark, and J. E. HiUis, Controlling the Salt Water Corrosion Peformance of Magnesium AZ91 Alloy, paper 850417, Society of Automotive Engineers, Detroit, Mich., 1985. 

These concentrations are vaUd only if salt water pH is between 6.5—8.5. 

Although numerous mud additives aid in obtaining the desired drilling fluid properties, water-based muds have three basic components water, reactive soHds, and inert soHds. The water forming the continuous phase may be fresh water, seawater, or salt water. The reactive soHds are composed of commercial clays, incorporated hydratable clays and shales from drilled formations, and polymeric materials, which may be suspended or dissolved in the water phase. SoHds, such as barite and hematite, are chemically inactive in most mud systems. Oil and synthetic muds contain, in addition, an organic Hquid as the continuous phase plus water as the discontinuous phase. 

Guar gum is a nonionic, branched-chain polysaccharide, a galactomaiman that is usually hydroxypropylated for use in drilling (52). It produces viscous solutions in fresh or salt water at concentrations of ca 3—6 kg/m (1—2 lb /bbl). It is used in soHds-free and low soflds muds and degrades rapidly above 80°C, limiting its use to shallow wells. 

Hydrating bentonite in fresh water before adding it to the mud greatly increases its efficiency when the makeup water is contaminated with salt and/or hardness. Prehydrated bentonite can be protected from dehydration by flgnosulfonate (70) or sulfomethylated tannin when used in saturated salt water. Salt water clays, such as sepioflte and attapulgite, provide no filtration control and are normally used with suitable filtration control agents. 

Acrylate and acrylamide polymers have several uses in drilling fluids, one of which is for filtration control. Sodium polyacrylates [9003-04-7] having molecular weights near 250,000 are exceUent temperature-stable filtration control agents for both fresh- and salt water muds, provided the concentration of water-soluble calcium is <400 mg/L (83). The calcium ions are precipitated using a carbonate such as soda ash, before adding the polyacrylate at concentrations up to ca 6 kg/m (3 Ib/bbl). 

A = 4.05 X lO " cm/(s-kPa)(4.1 X 10 cm/(s-atm)) and = 1.3 x 10 cm/s (4)//= 1 mPa-s(=cP), NaCl diffusivity in water = 1.6 x 10 cm /s, and solution density = 1 g/cm . Figure 4 shows typical results of this type of simulation of salt water permeation through an RO membrane. Increasing the Reynolds number in Figure 4a decreases the effect of concentration polarization. The effect of feed flow rate on NaCl rejection is shown in Figure 4b. Because the intrinsic rejection, R = 1 — Cp / defined in terms of the wall concentration, theoretically R should be independent of the Reynolds... 

Magnesium oxide is a typical acid scavenger for chlorinated mbbers. Compounds containing zinc oxide or magnesium oxide may tend to swell upon immersion in water. These inorganic salts have some water solubiHty and osmotic pressure causes the vulcanizates to imbibe water to equalize pressure (8,9). As such, vulcanizates tend to sweU more in fresh (distilled) water than in salt water. To minimize water sweU, insoluble salts such as lead oxides can be substituted. Because of the health concerns associated with lead, there is much mbber industry interest in other acid acceptors, such as synthetic... 

As of the 1990s, the EPA recommends that the dissolved form of silver be used as a better estimate of the bioavailable fraction and recommends using 85% of the total recoverable quantity. Thus, in fresh water at hardnesses of 50, 100, and 200 mg/L CaCO, the concentration of dissolved silver should not exceed 1.0, 3.5, and 11 Fg/L, respectively. The concentration of dissolved silver in salt water should not exceed 1.9 Fg/L (46). 

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