Inhibitors water systems

Ammonium dimolybdate corrosion inhibitor, vapor-phase Dicyclohexylamine nitrite 2-Dimethylamino-2-methyl-1-propanol corrosion inhibitor, waterfloods Cocodiamine acetate Etidronic acid corrosion inhibitor, water systems Acrylic resin Hydrazine corrosion inhibitor, water treatment Ammonium dimolybdate Calcium oxide Etidronic acid Lauramine 2-Mercaptobenzothiazole Myristamine Myristamine acetate PEG-8 dioleate PEG-3 tallow aminopropylamine PEG-8 tallow aminopropylamine Potassium phosphate Potassium thiocyanate Potassium tripolyphosphate Sodium chromate Sodium molybdate dihydrate... 

Cooling water systems are dosed with corrosion inhibitors, polymers to prevent solid deposition, and biocides to prevent the growth of microorganisms. 

Silicates. For many years, siUcates have been used to inhibit aqueous corrosion, particularly in potable water systems. Probably due to the complexity of siUcate chemistry, their mechanism of inhibition has not yet been firmly estabUshed. They are nonoxidizing and require oxygen to inhibit corrosion, so they are not passivators in the classical sense. Yet they do not form visible precipitates on the metal surface. They appear to inhibit by an adsorption mechanism. It is thought that siUca and iron corrosion products interact. However, recent work indicates that this interaction may not be necessary. SiUcates are slow-acting inhibitors in some cases, 2 or 3 weeks may be required to estabUsh protection fully. It is beheved that the polysiUcate ions or coUoidal siUca are the active species and these are formed slowly from monosilicic acid, which is the predorninant species in water at the pH levels maintained in cooling systems. 

Chromates are used to inhibit metal corrosion in recirculating water systems. When methanol was extensively used as an antifree2e, chromates could be successfully used as a corrosion inhibitor for cooling systems in locomotive diesels and automobiles (185). 

Petroleum greases and oils can be excellent corrosion inhibitors on a variety of alloys. The hydrophobic layer produced by oil or grease can prevent water from contacting surfaces and can, therefore, almost eliminate corrosion. Unfortunately, the addition of oil and grease cannot be recommended as a corrosion-reduction measure in cooling water systems for three basic reasons. 

Corrosion inhibitor 1 Bacterial control J Cooling-water system Consumption depends on make-up Chemicals are used to provide adequate reserve... 

Some salts, notably chromates, dichromates, silicates, borates and cinna-mates, have marked inhibitive power and are very effective in closed-circuit water systems. Care must be taken to ensure that a sufficient quantity of such anodic inhibitors as chromates is added, as otherwise attack, though occurring at fewer points, may be more severe at these points. Chromates and dichromates have little inhibitive power in strongly acid solutions. 

Contrary to the method of application of inhibitors to water systems, the... 

Industrial Cooling Water Systems Waters used for recirculating cooling systems can either be scaling or corrosive. Corrosive waters are treated with corrosion inhibitors which require monitoring for overall assessment of the treatment programme. 

Where low-toxicity, propylene glycol is employed (rather than the more common ethylene glycol), the inhibitor is more usually simply 30% dipotassium phosphate (K2HP04), so as to maintain the low-toxicity feature, and is then used at 3,000 ppm product. This same inhibitor is employed in the food industry in sweet water systems. 

Where glycols are added to both hot and cold water systems, it is common for the glycol to be supplied neat, preinhibited and buffered (although the glycol also may be supplied in a diluted and ready-to-use form). This formulation is an example of a type produced as an glycol inhibitor-pack concentrate ... 

BSI recommends in the table of water treatment for hot water systems that chromate inhibitors should not be used because of their undesirable impact on the environment. It should also be noted that some treatment chemicals are microbiologically degraded in storage. 

A type of waterside maintenance chemical treatment. Any of a very wide range of chemicals that prevent or reduce tendencies of deposition, fouling, scaling, corrosion, or other unwanted phenomena to occur in a water system. Typically for smaller boiler plants, individual inhibitors are blended together to produce various multifunctional formulations specific for particular water chemistry and/or operating conditions. Larger boiler plants tend to use individual active component inhibitors. 

Amine salts of ether carboxylates inhibit internal corrosion of oil storage tanks and pipelines [230]. Furthermore it is possible to use ether carboxylates as corrosion and scale inhibitors for industrial recirculating cooling water systems, metalworking fluids, and hydraulic fluids [28,231-233]. 

Evidence exists that the relative solubility of amines and inhibitors in heterogeneous oil-water systems could be decisive in formation of nitrosamines and blocking these reactions, Nitrosopyrrolidine formation in bacon predominates in the adipose tissue despite the fact that its precursor, proline, predominates in the lean tissue (5,6,7). Mottram and Patterson (8) partly attribute this phenomenon to the fact that the adipose tissue furnishes a medium in which nitrosation is favored, Massey, et al, (9) found that the presence of decane in a model heterogeneous system caused a 20-fold increase in rate of nitrosamine formation from lipophilic dihexylamine, but had no effect on nitrosation of hydrophilic pyrrolidine. Ascorbic acid in the presence of decane enhanced the synthesis of nitrosamines from lipophilic amines, but had no effect on nitrosation of pyrrolidine. The oil-soluble inhibitor ascorbyl palmitate had little influence on the formation of nitrosamines in the presence or absence of decane. 

Inhibitors may be classified according to their solution properties as either oil-soluble inhibitors, water-soluble inhibitors, or dispersible inhibitors. Chemical inhibitors act as film formers to protect the surface of the pipeline. Corrosion inhibitors, used for the protection of oil pipelines, are often complex mixtures. The majority of inhibitors used in oil production systems are nitrogenous and have been classified into the broad groupings given in Table 11-4. Typical corrosion inhibitors are shown in Table 11-5. For details, see also Chapter 6. 

T. M. McCullough. Emulsion minimizing corrosion inhibitor for naphtha/water systems. Patent US 5062992,1991. 

In this work we will focus on the use of the cubic phase as a delivery system for oligopeptides - Desmopressin, Lysine Vasopressin, Somatostatin and the Renin inhibitor H214/03. The amino acid sequences of these peptides are given in Table I. The work focuses on the cubic phase as a subcutaneous or intramuscular depot for extended release of peptide drugs, and as a vehicle for peptide uptake in the Gl-tract. Several examples of how the peptide drugs interact with this lipid-water system will be given in terms of phase behaviour, peptide self-diffusion, in vitro and in vivo release kinetics, and the ability of the cubic phase to protect peptides from enzymatic degradation in vitro. Part of this work has been described elsewhere (4-6). 

Although the use of inhibitors can mitigate corrosion to some extent in such hostile environments (15) designing systems with appropriate phase behaviour under bottom hole conditions is difficult. To date oil based inhibitor carrier systems have been employed but these require large volumes of fluid circulation and it is often difficult to maintain a continuous oil wet surface on the tubulars. A water-inhibitor system would overcome many of these problems since the sour gas fluid is already saturated with water in the reservoir. Such a system, however, remains to be designed. 

Since HtS dissolved in water is very corrosive to carbon 4 steel, a comprehensive corrosion-control program is being conducted. In the field, each well is treated once per month by displacing inhibitor down to the perfora-. tions with stock tank oil. Corrosion coupons in the flow-lines are inspected every 6 months Little corrosion has been detected in the field. In the plants, corrosion in-hibitor is added daily to the gas-sweetening solvent, the salt water system, and the stabilizer overhead. Inhibitor is -Jj also added to bulk chemicals as received. Numerous corrosion coupons and probes are installed in each facility and are pulled for inspection every 1 to 3 months Corrosion rates have been low (less than I mil/year) asY result of the inhibitor injection program. 

NOTE Many closed-loop cooling water systems are not, in fact, closed, as they contain open-top, return-water tanks. This provides a continuous source of oxygen from the air into the system, with the result that the risk of corrosion greatly increases. Adequate attention should be paid to countering this risk, perhaps by an improved corrosion-inhibitor treatment or a floating blanket or plastic balls in the water tank (which help to minimize the ingress of air). 

Despite some limitations, the wide range of inhibitor effects of O + P phosphates has meant that this inhibitor group, along with chromates, has been perhaps the most important formulation material employed in cooling water systems. 

Apart from sodium hypochlorite and sodium bromide solutions, almost all other liquid biocides (or biocide intermediates) are nonoxidizer types. Most nonoxidizers are manufactured by specialist chemical companies, who sell these branded products for scores of different sanitizing or disinfection applications, of which cooling water system treatment is only one. These chemicals may be merely renamed (according to subregistration permits) or they may be blended with other biocides or inhibitors to form new and different products with accordingly modified properties. Some biocides may only be available from the primary manufacturer, often as extremely concentrated and hazardous materials. These chemicals will then usually require some form of dilution, stabilization, and quality verification before being incorporated into a service company s product line. 

Downward, Brian L. Failon, Brian K. A New, All Organic High Performance Corrosion Inhibitor for Industrial Cooling Water Systems. Albright Wilson, 1996. 

FIGURE 4.2 Pressure-temperature diagrams, (a) Methane + water or nitrogen + water system in the hydrate region, (b) Hydrocarbon + water systems with upper quadruple points, (c) Multicomponent natural gas + water systems, (d) Hydrocarbon + water systems with upper quadruple points and inhibitors. 

Equation 4.7 was based on more than 100 experimental determinations of equilibrium temperature lowering in a given natural gas-water system in the inhibition concentration range of 5-25 wt% of the free water. The equation was used to correlate data for alcohols and ammonia inhibitors. Hammerschmidt (1939) provided for a modification of the molecular weight M when salts were used as inhibitors. Unfortunately, no information on the gas composition and no listing of the individual experimental data were provided. The assumption is normally made that the gases used by Hammerschmidt were methane-rich. 

With few exceptions (as indicated in the table), all structure H equilibria data were obtained with methane as the small component. Also because there were always four phases present (Lw-H-V-Lhc) with three components (including water) the Gibbs Phase Rule provides for only one composition of each phase which satisfies the equilibrium conditions. Consequently all data were taken without measurement of any phase composition, and only the equilibrium temperature and pressure of the four phases are reported. Due to the paucity of structure H data, included here are one binary including nitrogen and three structure H systems with inhibitor. Such systems clearly illustrate the need for more structure H data. 

Allen and Bevan (80) have applied the SMD technique to the study of reversible inhibitors of monoamine oxidase B, and this paper will be used as an example for discussion of the constant velocity SMD pulling method. They used the Gromacs suite of biomolecular simulation programs (18) with the united-atom Gromos 43al force field to parameterize the lipid bilayer, protein, and small-molecule inhibitors. The protein was inserted into their mixed bilayer composed of phosphatidyl choline (POPC) and phosphatidyl ethanolamine (POPE) lipids in a ratio known to be consistent for a mitochondrial membrane. Each inhibitor-bound system studied was preequilibrated in a periodic box of SPC water (20) with the simulations run using the NPT ensemble at 300 K and 1 atm pressure for 20 ns. Full atomic coordinates and velocities were saved in 200-ps increments giving five replicates for each inhibitor-bound system. A dummy atom was attached to an atom (the SMD atom shown in Fig. 7) of the inhibitor nearest to the... 

---