Water-based fluids

The largest volume of hydrauHc fluids are mineral oils containing additives to meet specific requirements. These fluids comprise over 80% of the world demand (ca 3.6 x 10 L (944 x 10 gal))- In contrast world demand for fire-resistant fluids is only about 5% of the total industrial fluid market. Fire-resistant fluids are classified as high water-base fluids, water-in-oil emulsions, glycols, and phosphate esters. Polyolesters having shear-stable mist suppressant also meet some fire-resistant tests. 

High Water-Base Fluids. These water-base fluids have very high fire resistance because as Httle as 5% of the fluid is combustible. Water alone, however, lacks several important quaUties as a hydrauHc fluid. The viscosity is so low that it has Httle value as a sealing fluid water has Httle or no abiHty to prevent wear or reduce friction under boundary-lubrication conditions and water cannot prevent mst. These shortcomings can be alleviated in part by use of suitable additives. Several types of high water-based fluids commercially available are soluble oils, ie, od-in-water emulsions microemulsions tme water solutions, called synthetics and thickened microemulsions. These last have viscosity and performance characteristics similar to other types of hydrauHc fluids. 

Clear Brines. Brine solutions are made from formation saltwater, seawater, or bay water, as well as from prepared saltwater. They do not contain viscosifers or weighting materials. Formation water-base fluids should be treated for emulsion formation and for wettability problems. They should be checked on location to ensure that they do not form a stable emulsion with the reservoir... 

When a water-based fluid makes contact with a flame or a hot surface its water component evaporates and forms a steam blanket that displaces oxygen from around the hot area, and this obviates the risk of fire. Water-based products all contain at least 35% water. Because water can be lost by evaporation, they should not be subjected to operating temperatures above about 60°C (140°F). Table 52.8 shows a comparison of oil and FR fluids. 

Some of the recently developed high-performance EP soluble oils have a cutting performance that almost matches that of additive-type neat oils, and they are particularly suitable for demanding operations in machine tools whose design allows the use of water-based fluids. 

Two factors militate against the universal use of water-based fluids. Very severe machining operations call for a lubrication performance that is beyond the capacity of such fluids, and the design of some machine tools means that water cannot be used because of the risk of cross-contamination with machine lubricants. In these instances, neat cutting oil is the only fluid that can provide the required performance. 

Neutralized sulfonated asphalt (i.e., salts of sulfonated asphalt and their blends with materials such as Gilsonite, blown asphalt, lignite, and mixtures of the latter compounds) are commonly used as additives in drilling fluids. These additives, however, cause some foaming in water or water-based fluids. Furthermore, these additives are only partially soluble in the fluids. Therefore, liquid additives have been developed to overcome some of the problems associated with the use of dry additives. On the other hand, with liquid compositions containing polyglycols, stability problems can arise. Stable compositions can be obtained by special methods of preparation [1407]. In particular first the viscosifier is mixed with water, then the polyglycol, and finally the sulfonated asphalt is added. 

Clays or shales have the ability to absorb water, thus causing the instability of wells either because of the swelling of some mineral species or because the supporting pressure is suppressed by modification of the pore pressure. The response of a shale to a water-based fluid depends on its initial water activity and on the composition of the fluid. The behavior of shales can be classified into either deformation mechanisms or transport mechanisms [1765]. Optimization of mud salinity, density, and filter-cake properties is important in achieving optimal shale stability and drilling efficiency with water-based mud. 

An antifreeze is defined as an additive that, when added to a water-based fluid, will reduce the freezing point of the mixture [1671]. Antifreezes are used in mechanical equipment in environments below the freezing point to prevent the freezing of heat-transfer fluids. Another field of application is in cementing jobs to allow operation below the freezing point. 

Fracturing fluids are often classified into water-based fluids, oil-based fluids, alcohol-based fluids, emulsion fluids, and foam-based fluids. 

A. Audibert and J. F. Argillier. Process and water-based fluid utilizing hydrophobically modified guar gums as filtrate (loss) reducer (procede et fluide a base d eau utilisant des guars modifiees hydrophobiquement comme reducteur de filtrat). Patent EP 722036, 1996. 

A. Audibert, J. F. Argillier, L. Bailey, and P. I. Reid. Procedure and water-based fluid utilizing hydrophobically modified cellulose derivatives as filtrate reducer. Patent EP 670359, 1995. 

Hatton RE. 1962. Water-base Fluids. In Hydraulic Fluids. New York Reinhold Publishing Corporation 13 273-287. 

The majority of hydraulic fracturing treatments are performed using water-based fluids foams (with nitrogen or carbon dioxide as the gas phase) have been used extensively in recent years to reduce formation damage. Oil-external emulsions have also been used for... 

Perhaps the key development that began to tip the balance in favor of water-base fluids was recognition that formation damage by water could be controlled. Control was first provided by inorganic salts dissolved in the water. Operators knew that native brine solutions (usually 6-37% NaCl) caused little or no damage to the formations they were produced from. 

With respect to the Agency, Section 5 of TSCA has made EPA more familiar with trends in the metalworking fluids industry, the chemical components of the fluids, and the interactions between the various components. Major trends in the industry are (1) a shift from the traditional oil-based to the rapidly growing water-based fluids (2) a shift from the use of the nitrosating agent nitrite as a rust inhibitor (3) the use of multifunctional additives and (4) the careful monitoring of various factors and additives associated with these fluids. 

Unfortunately, not all combinations of chemical additives in water-based fluids are completely compatible, and side reactions leading to various byproducts have been noted. The best known of these side reactions is the reaction between the corrosion inhibitor nitrite and the emulsifiers di- and triethanolamine (7) to form N-nitrosodiethanolamine (NDE1A), a nitrosamine reported to have carcinogenic activity (8, 9, 10). In fact, most nitrosamines are carcinogenic, and no animal species which has been tested is resistant to nitrosa mine-induced cancer. Although there is no direct evidence that firmly links human cancer to nitrosamines, it is unlikely that humans should be uniquely resistant. 

Because water-based fluids do not last as long as the more conventional oil-based fluids, careful monitoring of fluids is required. In addition to the standard analyses for pH, dirt and metal fines, dissolved iron, and tramp oil, the introduction of various chemical additives has required the additional monitoring of organic amines, ammonia, rust inhibitors, water hardness, and even nitrosamlnes in some cases. 

Microorganisms have been shown to catalyze the formation of nitrosamines from secondary amines in the presence of nitrite (26). The amount of nitrosamine formed, however, increased as the basicity of the parent amine decreased, presumably due to the increase in the amount of unprotonated amine present (27). This reaction is especially important with respect to metalworking fluids since water-based fluids are inevitably contaminated by microbes and fungi. Microbes are thought to catalyze nitrosamine formation by lowering the pH of the medium or catalysis by one or more unidentified metabolic products. 

Surfactants that form micelles have also been shown to accelerate the formation of nitrosamlnes from amines and nitrite (33.) A rate enhancement of up to 80 0-fold was observed for the nitrosation of dihexylamine by nitrite in the presence of the cationic surfactant decyltrimethylammonium bromide (DTAB) at pH 3.5. A critical micelle concentration (CMC) of 0.08% of DTAB was required to cause this effect, which was attributed to a micelle with the hydrocarbon chains buried in the interior of the micelle. The positively-charged ends of the micelle would then cause an aggregation of free nitrosatable amine relative to protonated amine and thus lead to rate enhancements. Since surfactants are commonly used in water-based fluids (25-50% lubricating agent or 10-2 0% emulsifier in concentrates), concentrations above the CMC of a micelle-forming surfactant could enhance the formation of nitrosamines. 

Abstract The biological effects of fullerenes and, in particular, of C60 have been recognized since long time. One of the problems which hindered the application of fullerenes in medicinal chemistry regards their insolubility in water and water-based fluids. In the present chapter it is reported that C60 and C70 fullerenes are soluble in vegetable oils, in general, in esters of fatty acids and in free fatty acids. These results pave the way in the utilization of vegetable oils as vehicles in the delivery of fullerenes for both topical applications and internal use (e.g., intramuscular injection). 

The gauge glass will normally be somewhat colder than the process vessel as a result of ambient-heat losses (an exception to this would be a refrigerated process). For every 100°F decrease in the gauge-glass temperature or level-trol temperature, the specific gravity of the liquid in the glass increases by 5%. This rule of thumb is typical for hydrocarbons only. Aqueous (water-based) fluids are totally different. 

The delivery of nanoparticles in the human body usually requires suspending the nanoparticles in a water-based fluid. In-vitro applications also usually require an aqueous environment. Magnetic nanoparticles must remain... 

Low-temperature HTFs are routinely used in various process cooling applications. Examples of these HTFs can be found in the literature. Some of these fluids are aqueous (or water based) and some are nonaqu-eous. In this category, the lowest operating temperature of the fluids is in the range of 0 to —50°C. Different chemistries that are utilized in this temperature range include mainly water-based fluids. 

When a freeze point suppressant is added to water, it loses its heat transfer characteristics to some extent, which depends on the concentration of the suppressant. However, water-based fluids still exhibit a very high heat transfer coefficient compared to nonaqueous fluids. Nonaqueous fluids such as aromatics, aliphatics, and silicones are used in such applications when an aqueous fluid exhibits very high viscosity (>50cP) at the lowest operating temperature or its freezing point is very close to the refrigerant temperature in the evaporator. 

Some examples of low-temperature water-based fluids are discussed below. 

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