Passivating inhibitors cause a large anodic shift of the corrosion poten- tial, forcing the metallic surface into the ... such as phosphate, tungstate, and molybdate, that require the presence of oxygen to passivate steel. .... in metal-cleaning proc
Corrosion is controlled by anodic (passivating) inhibitors including nitrate and chromate as well as by cathodic (e.g., zinc salt) inhibitors. Organic inhibitors (e.g., benzotriazole) are sometimes used as secondary inhibitors, especially when excess
Natalya V. Likhanova. Additional information is available at the end of the chapter http://dx.doi.org/10.5772/57252. 1. Introduction. In most industries whose facilities are constituted by metallic structures, the phenomenon of corrosion is invariabl
resistance, corrosion inhibition, organic amines, marine environment, diffusion, migration ... This design allows variability in the type of concrete membrane, i.e., ...
facility can be catastrophic if proper methods of prevention are not utilized. ..... High-temperature corrosion on carburized steels that forms a porous scale of.
the performance of carbon dioxide corrosion inhibitors for oilfield pipelines in the West .... corrosion. The corrosion rate increased nearly 7-fold for both types of ...
Nov 20, 2007 - dependent on the structure and chemical properties of the species formed under the specific ... The synthesized triazo phosphonates are used as inhibitors ..... serves as the basis for all modern corrosion inhibitor formulations.
... 4% of the GDP. Corrosion not only has economic implications, but also social and these engage the safety and ...... synthesized under microwave irradiation and evaluated as CIs for acid environment. Weight loss and .... alcohols isolated from sug
Introduction. Acid treatments have been applied to wells in oil and gas bearing rock formations for many years. Acidizing is probably the most widely used work-over and stimulation practice in the oil industry. By dissolving acid soluble components w
organic and inorganic corrosion inhibitors to the environment has provoked the search .... Polarization studies indicated that inhibitors are acted as mixed type.
Jul 26, 2014 - Structure Under Simulated Field Service Environment. L. Shi, J. Ye ... To guide the scientific applications of organic corrosion inhibitors, China is carrying .... carbon steel were used in this study. ..... reinforcement rust efficien
and 85% corrosion inhibition efficiency (CIE) respectively while the other salts gave less than 40% ..... 93-97, 2005.  V. P. Persiantsava, (1987) âChemistry ...
Apr 21, 1982 - 'A multifunctional corrosion inhibitor consisting essen-. 18, 19; 106/14.12, ..... concentration upon the breakdown of passivity of type face active ...
Dec 1, 2017 - Figure 3a,b show much less corrosion product, but still show some local attack on the sample in the inhibitor .... Schematic summary of synthesis of thermosensitive ionic microgels via quaternized. Figure 6. ..... are those which are fr
Feb 25, 2013 - Most well-known acid inhibitors for steel corrosion are ... where, Icorr.add and Icorr.free are the corrosion rates in free and inhibited acid, ...
Aug 11, 2018 - Three organic environmentally friendly corrosion inhibitors were ..... metal, acting as a mixed type inhibitor by absorbing onto the metal surface ...
Jun 15, 1988 - phthalocyanines as corrosion inhibiting coatings - poyeriz by .... inhibitors of the phthalocyanine type show promise in a number of forms.
electromotive force (EMF) of iron oxidation reaction with oxygen in the neutral environment at the presence of water. Under real conditions of subterranean.
Feb 8, 2012 - Among the various methods to avoid or prevent destruction or degradation of metal surface, the corrosion .... When the concentrations of inhibitor becomes high enough, the cathodic current density at the ... Organic compounds used as in
In principle, any method to determine the corrosion rate can be used to test a corrosion inhibitor. The primary ... regarded as a screening test in a preliminary stage of inhibitor evaluation because it may discriminate poor inhibitors from ..... Fil
corrosion inhibition of mild steel in 1M H2SO4 solution are given in Table 3 ..... H[sub 2]SO[sub 4] Containing Benzotriazole, Journal of The Elec- trochemical ...
23]. GokhanGece (2011) review from literatures the use of many types of drugs as corrosion inhibitors of various metals. . Some drugs (such as ampicillin, ...
potentials and statistical mechanical methods to answer many application .... Fresh sour brine was prepared every day for the testing period. Inhibitor Solutions. A 10000 ..... TABLE 6: MC Simulation Results for Adsorption: Number of Occupied ...
Apr 1, 2014 - ACI Committees 130, Sustainability of Concrete; 222, Corrosion of Metals in Concrete;. 224, Cracking; 318-B, ... Code); and Joint ACI-ASCE Committees 408, Development and Splicing of Deformed. Bars; 445, Shear and Torsion; ..... Table 8
1&135683 z-v/a v,
A.'von KOEPPEN, A. F. PASOWICZ, and B. A. METZ, Wright Chemical Corp.
Non-Chromate Corrosion Inhibitors Different types of nitrogen-containing, organic non-chromate corrosion inhibitors were developed that provide excellent protection against corrosion of heated steel tubes and coupons in aqueous media, using a 100 ppm dosage, and applied in a pH range as low 5.0 and as high as 9.0. Chromates and phosphates, both typical inorganic anodic inhibitors, have been used separately or in combination for corrosion prevention in cooling tower recirculation systems. When used alone the chromates required concentrations above 200 ppm as Na2Cr0,. In combination with poly. phosphates the total level of treatment is reduced to only 40-60ppm. Chromates owe their protective action to their ability to form a thin, passivating film directly on the anodic portion of metal. Besides chromates and phosphates (or their combinations) silicates, nitrites and ferrocyanides are also used. Salts of zinc, nickel, manganese and trivalent chromium are typical examples of cathodic inhibitors. These materials have the ability to form adherent, insoluble hydroxides at the cathodic area and thus cause cathodic polarization. But the use of polyphosphates has drawbacks. They tend to hydrolyze and lose their sequestering ability. Besides this, they act as nutrients and accelerate the growth of slime or algae. The US. Public Health Service recommends reduction of hexavalent chromium level to 0.05 ppm. Above this level it may have some toxic effect on humans, fish and marine life. New and more stringent pollution control laws aie being adopted by the states as a result of the Water Quality Act of 1965, and therefore, most of the major treatment suppliers have non-chromic material on the market, Summarizing, we can say that all of the commonly used corrosion inhibitor treatments based on chromates and phosphates at the present time can contribute t o the pollutiok load, if the cooling water effluent is not diluate or treated properly before discharge. The economics of establishing waste treatment systems for treatment of chromates and phosphates may rule out their use. Therefore, it was decided to start on an extensive R&D program with the aim of producing a group of non-chromate corrosion inhibitors. Nitrogen-containing, organic formulations Ovet forty different nitrogen-containiug organic-zinc formulations were screened, using a simplified version of cooling tower (see figure). Of this group only three materials showed promise which subsequently were formulated and tested in the experimental cooling tower. These materials will henceforth be identified as Inhibitor A, Inhibitor B and Inhibitor C. Inhibitors A and C consist of a blend of aroma. tic monocyclic nitrogen compounds with phosphonate and zinc. The difference between A and C lies in the percentage of the constituents. Inhibitor B consists of aromatic hetero-
cyclic nitrogen compounds wiht phosphonate and zinc. For make-up Chicago tap water fortified with sodium chloride was used. Experimental cooling tower There are a wide variety of laboratory tests designed to evaluate .the performance of corrosion inhibitors. The relative merits of some commonly known laboratory test methods used in the industry were studied by NACE Task Group T-5C-I. Their findings showed that only results obtained in dynamic tests correlated reasonably well with the results obtained from the pilot plant tests. Our corrosion tests were obtained in bench-scale test units designed by the staff of Wright Chemical. These units allow a close study of the variables such as temperature and pH, quality of water flow conditions, growth of scale, slime, and algae, inhibitors residual, amount of dissolved gases, etc. The system consists of a basin, a feed water tank, a centrifugal pump, glass jackets, a Plexiglas tower and a mild steel heat exchanger. Chemical treatment and make-up water are fed continuously from chemical and feed water-tanks. In this system heated tap water at 120 + 3 F, was circulated at a velocity of one foot per second (approx). The temperature was obtained by the use of cartridge heaters. The desired number of cycles of concentration is obtained by adjusting the blowdown valve. The corrosion teg specimens were C-1018 steel coupons 3 in. in length and 3/8 in. in diameter. These coupons were weighed before and after treatment. The loss in weight divided by duration of exposure was then extrapolated to give weight loss in mils/ year. A C-1018 mild steel condenser tube, half inch O.D., used as heat exchanger, was also inserted. Corrosion of the tube was measured by visual and microscopic observation. The severity of corrosion was facilitated by adding sodium chloride to the circulating water. Performance under acid conditions Laboratory tests performed in experimental cooling towers at 120 F and pH 5.0 to 6.5, exposed for 20 to 30 days, produced the following results on test coupons.
Corrosion Inhibitor A corrosion Inhibitor
Corrosion Rate miUs pH perye=
250 to 290 250 to 300 520 to 580
Shock Treat- Conc. ments Cycles
Mechanism of Inhibitive Action of Organic Corrosion Inhibitors According to Wig(’)the protection of iron against cor- zinc ion should give protection to steel and iron and nonrosion by chromates is due to the formation of a surface ferrous metals at a lower treatment level, to make this compound. He believes that the bonding between : application feasible for cooling water treatment. There was a disagreement on whether, in the case of acid chromate and metal is chemical, but the metal lattice IS intact, and no stoichiometric compound forms. attack, the inhibitors (e.g., amines and thioureas) act by retarding the anodic or the cathodic reaction, or whether they coat the surface generally and prevent replenishment of acid. Extensive work by Hoar and Holiday(io) has shown that there is interference with both cathodic and anodic reaction. The quinolines are primary anodic inhibitors, but at the high concentration they act as cathodic inhibitors. The thioureas inhibit both reactions the cathodic reaction mainly at low concentration and the anodic reaction mainly at high concentration. ~
surface compound formed by chromates. A similar point of view was advocated by Rosenfeld and Akimov.(*) The alkali phosphates are considered to be less efficient inhibitors than chromates. The use of sodium hexametha hosphate has been described in detail by Hatch and R i ~ e . ( ~Hatch(4) f explains the protective action of phosphates towards steel is due to deposition of phosphate on the microcathode regions of the surface. This raises the cathodic polarization and simultaneously reduces the strength of the current involved in the corrosion processes. According to Hatch the formation of the protective fdm is a self-retarding process; the deposition of protective fdm reduces the current which causes its formation on the metal surface. It was found by Raistrick(s) that sodium tetrametaphosphate is not a corrosion inhibitor, and that trimetaphosphate is a weak inhibitor.
Adsorption theory One of the first published works on organic nitrogencontaining corrosion inhibitors could be traced to the work of Sieverts and Lueg(”) who proposed the adsorption theory of rotective activity. This theory was supported by KreuzfeldK’) in his work on coal tar distillates as inhibitors for steel in sulphuric acid and Hoar(i3) who studied the action of heterocyclic nitrogen bases, namely quinoline a n d acridine derivates. Hackerman and Markides(I4) in their paper criticize the “overvoltage” theory and propose that inhibitor action results from the increased resistance to current flow caused by a barrier of physically adsorbed inhibitor and by reduction in metal reactivity by a chemi-sorbed inhibitor. A considerable amount of work was done on nitrogen-containing organic compounds by George and Hackerman,(”) Kohler and p f o y ~ p (and ~ ~ Jones ) and Barett(”).
Polar organic compounds A literature study of local and foreign publications revealed that there exist a number qf polar organic compounds wfiich can be used as corrosion inhibitors. According to Mann and his associates(b a group of nitrogen---_--------------containing materials especially aliphatic and aromatic -------Metal Metal amines give a good corrosion protection to metal in acid A protective layer of amine cations, media. Mann, et al, believe that amine cations are absorbed Kuznetsow and Jofa(”) stated that the ions of nitroon the cathodic regions of the metal surface, undergoing dissolution in such a way that a nitrogen atom is directly gen-containing inhibitors are capable of being adsorbed prelinked to the metal. A layer of amine cations, similar to the dominantly on the most active regions of the dissolving monomolecular layer, is formed on the metal surface, metal, e.g., on the anodic areas. They propose that surfacescreening the metal surface and preventing the corrosion active ions of the inhibitors change the adsorption potential of the metal, and that this leads to a change in the process from taking place. In his book on the theory of corrosion protection, hydrogen overvoltage. T o m a ~ h o w ( ~stated ) that a group of nitrogen containing organic materials gives a good corrosion inhibition in acid Overvoltage theory media. These materials act as principally anodic inhibitors. In their investigation Kuznetsow and Jofa are supporting They shield the iron surface from the corrosive media. This the “Overvoltage theory” called also the “Theory of group includes quaternary ammonium bases and their Cathodic Action”. This is actually not a new theory but derivatives, Enaphthylamine, pyridine, quinoline, naphtha- was originated at a much earlier date by Warner(’’), Tile *) and others. The essenquinoline, naphthylquinoline, ortho-tolyl thiourea, aniline, and Kaiser(*’), Mann, et al(h ethylamine, diethylamine, acridine, acriflavin, etc. These tial of the overvoltage theory may be summarized as folmaterials are used for combating acid corrosion, as additives lows: Molecules, ions, or colloidal particles block the for pickling iron and steel in acids, and also for protection cathodic regions on the metal surface and raise the hydroof vessels in storace and transportation of acids. It was gen overvoltage to such an extent that discharge of hydroanticipated that the addition of ;Ither organic materials and gen ions can lake pl3c.c only very slowly. Ket&lng of the
INDUSTRIAL WATER ENGINEERING
cathodic process leads, of course, to the same extent to retardation of the anodic process. This anodic retardation, however, is entirely due to the slower discharge of hydro gen ions and there exists no direct action of the inhibitors on the anodic reactions. The theory of overvoltage (or cathodic activity) has been recently overthrown by the discovery that all organic inhibitors, without exception, act to a greater degree as polarizers of the anodic process than of the cathodic process. No direct relationship between the effectiveness of inhibitors and the rise in hydrogen overvoltage could be found. The fdm or chemisorption theory of inhibitive action was active1 supported b Hackerman and Markides(I4), Shdov, ~), and Hackeret id(”), Lepin(’4, D t ~ b i n i n ( ~ George man(”), Cox, et al(z4) and others. Chemisorption theory The proponents of the fdm theory believe that the effective protection of metals by inhibitors is due to the formation of a layer of products of reaction between the metal, the inhibitor, and the ions of the corrosive medium on the metal surface. Experiments have shown that all substances which are active corrosion inhibitors are capable of reacting with metal or its ions, forming insoluble or only slightl soluble compounds. Several investigators(14, ’2 ’1 classified this process as “chemisorption” namely a process of adsorption on the surface by means of an heterogeneous reaction which gradually spreads over the whole surface. This means that the molecules of the surrounding medium react in this process with the molecules or atoms of the solid phase, producing a new substance in the form of an independent phase. (Example - oxygen reaction with copper turnings, formation of magnesium sulfate on MgO particles in a fluidized bed system, etc.) The process of chemisorption has often become much slower after a time, because such a compact layer of reaction product is formed on the surface that the molecules of the reacting media cannot penetrate. Hackerman, Hurd and Armand(") proved that inhibitot efficiencies within a series of cyclic imines and secondary amines show differences which are clearly related to differ. ences in their molecular structure. Finley and Hacker. m a d z 6 ) investigated the inhibitor effectiveness in 1N acid solution using different polymethylimines. Their study in. cluded compounds with four to seven-CH,-groups thal showed an increase in inhibitor effectiveness with increasing Strom ring size by about 20 percent per-CH,-group. berg(27) reported that in case of amino acids a slight differ. ence in molecular structure in a long alkyl chain (like addi. tional CH, group, etc.) does not affect the material to a great extent. Slight differences in the carbon chain between functional groups, however, result in more apparent differ. ences. Frenkhouser studied the inhibition with secondary acetylenic alcohols(z8). His study indicated that I-hexyn. 3-01 and other secondary acetylenic alcohols can be ef. ficiently used as acid corrosion inhibitors. We would like to emphasize that nearly all of these in. hibiting studies were done in acid solution and not in re circulating cooling systems where a much -greater amount ot oxygen a i d higher pli value prevail. ”3
It is evident that the new non-chromate inhibitors A and B provide an excellent protection against corrosion of heated steel tubes and coupons, using 100 ppm dosage and acid conditions. The same materials were tested at the pH as low with excellent results. as 4.5-5.0 Performance under alkaline conditions Laboratory tests performed at 120 F and pH between 8.0 to 9.0 in experimental cooling towers produced the following results on coupons exposed for 20 to 30 da Again, it is evident that Inhibitor C provides good protection against corrosion and scaling of heated steel tubes and coupons, using a 100 ppm dosage when applied under alkaline conditions. It was also found that a high dosage of chlorine (as high as 20 ppm) did not adversely affect the performance of Inhibitor C. Therefore, it is safe to assume that the addition Conosion Rate Inhibitor
Shock Treat. Cone. ments Cycles -
of chlorine does not increase corrosion. This is a very important point because of the susceptibility of most organic materials to chlorine. Because of the existing restrictions and limitations of conventional treatments a substantial demand for new nonchromate treatments is obvious. They should provide: 1. Effective corrosion inhibition. 2. Low toxicity of treatment combined with a low pollution load. 3. High stability. 4. Compatibility with chlorine and other biocides. 5. Preventive scale deposition in alkaline conditions. 6. Easy feed and control. Results of this laboratory study and evaluation in the field show that the newly developed organic non-chromate inhibitors provide excellent protection against corrosion of steel surfaces. These materials which are not subject to deposit formation from the inhibitor are low in toxicity and high in stability. They can be produced in ready to use liquid form, thus providing an ease of feed and control. They are also compatible with chlorine and other biocides. Some case histories 0 A chemical plant in Texas had operated their cooling towers successfully for years using a zinc-chromate-organic corrosion inhibitor. Corrosion rates of 0.5-0.8mpy were normally encountered. The make up of these towers was APRIWMAY
Lobomtory cooling tower used to evaluote the nom chromte corrosion inhibitors consists of a basin, o feed-
clarified river water. PH Total Alkalinity Calcium Hardness Magnesium Hardness Total Hardness Sodium Chloride Sodium Sulfate Silica Total Dissolved Solids
In early 1970 their engineering department decided to
use one of their towers to “test” non-chromate inhibitors. Their purpose was to anticipate and prepare for possible restriction against chrome in their area. The tower selected had a circulation rate of 4,000 gpm and operated, normally, at aAT of 1012 F. 28
INDUSTRIAL WATER ENGINEERING
water tonk. o centrifugal pump, gloss jockets, a plexigloss tower and o mild steel heat exchonger.
The inhibitor chosen was a blend of silica, alkali and polyelectrolyte. Treatment was begun at a level of 150 ppm with no pH control (system pH averaged 8.1-8.2).Within a few days corrosion rates on a corrater began to give readings of 2030 mpy. Finally, after 3 months, the “test” was discontinued. Average corrosion rate was 29 myp as determined by a corrater. Next, Inhibitor A was tried. A treatment level of 100 ppm was maintained and pH control was enlisted to keep a range of 58-62 at a l l times. Treatment continued for six months. At no time did the corrater show rates higher than 1.8 mpy. At the end of the six month trial, the average corrosion rate from the corrater was 1.2 mpy. This was confirmed by coupons placed in the system at the initiation of the trial. The plant has returned to the use of the zinc-chromateorganic inhibitor since the use cost is lower. They are ready,
and, as a result of their testing, confident that they can go to the use of Inhibitor A, if and when it becomes necessary, due to pollution restrictions. 0 At a major defense contract facility on the west coast, the situation was one of urgency. They had just completed construction of a new plant in a suburban community when the community passed extremely rigid poUution control ordinances. To comply with these ordinances meant the elimination of the planned use of chromate inhibitors in the several medium sue cooling towers located at the facility. The community supplied a make up water of the following
quality: PH 8.3 Total Alkalinity 124 ppm Calcium Hardness 86 ppm Magnesium Hardness 20 PPm Total Hardness 106 ppm Sodium Chloride 1% ppm Sodium Sulfate 480 ppm Silica 9 ppm Total Dissolved Solids 819 ppm Since a limit was also placed on the dissolved solids content of the plant effluent, it was decided to use Inhibitor C as the corrosion and scale inhibitor, with no pH control. The average tower had a circulation rate of 2,000 gpm with a 15 F temperature drop. Treatment with Inhibitor C at 100 ppm has been in effect on a commercial basis for several months as of this writing. Corrosion rates have been as high as 2.3 mpy, but no higher. No scale is being encountered with the systems operating at 3 cycles of concentration. 0 Another example of awareness to possible future pollution restrictions involves a glass manufacturing plant in the south. This plant obtains all of its cooling water from a 500,000 gallon capacity spray pond. The water is circulated at a rate of approximately 3,000 gpm and is used in glass coolers to maintain the quality of the finished product. Corrosion and scale control are critical. The spray pond had been treated, for 8 years with a chromate inhibitor and pH control. In light of the increasing pollution awareness in the surrounding area, and because of occasional over-flowing of the pond, it was decided to embark on a program of non-chromate inhibition. With a make-up of the following quality: PH 7.5 Total Alkalinity 35 PPm Calcium Hardness 158 ppm Total Hardness 180 ppm Sodium Chloride 21 PPm Sodium Sulfate 255 ppm Silica 6 ppm 331 ppm Total Dissolved Solids It was decided to use Inhibitor C with muriatic acid for pH control. The muriatic acid was used rather than suifuric acid to be certain that no excess sulfates were encountered which might lead to calcium sulfate scale (as previously stated, scale control was essential). Treatment at 100.ppm at a pH level of 7.0-8.0 was
begun. After a period of five months operation, coupons showed a corrosion rate of 1.1 mpy, and no scaling was encountered. The plant was advised that, should they wish, the use of acid could be discontinued. Since there was no automated pH control of acid addition, this suggestion was accepted readily. To date, the system has operated with the same 100 ppm level of Inhibitor C and at a pH range of 8.1-8.8. Corrosion rates are being maintained at a level of around 1 mpy and no scaling problems are being encountered. Additional formulations are presently under development and undergoing field testing to expand the capability to meet all pollution restrictions. 0
References (1) H. H. Uhlig. Corrosion, 3, 1, 173 (1947) ( 2 ) 1. L. Rosenfeld and G. V. Akimov, “Investigations in the Cor-
rosion of Metals” Izd. Akad. Nauk. S.S.S.R. vol. 1 p. 203 (1951) (3) G. BlHatch and 0.Rice, Ind. Eng. Chem. 37,710715 (1945) (4) B. B. Hatch, Ind. Eng. Chem. 44, 8, 17801786 (1952) (5) B. Raistrick, Chem. Ind. 19,408-414 (1952) (6) C. A. MaM, Trans. Electrochem. SOC. 69, 115 (1936) ( I ) C. A. Mann, B. E. Lauer and C. T. Hultm, Ind. Eng. Chem. 28, 2, 159-163 (1936) (8) C. A. Mann, B. E. Lauer and C. T. Hultin, Ind. Eng. Chem. 28, 9,1048-1051 (1936) (9) N. D. Tomashow, “Theory of Corrosion and Protection of Metals” Book, p. 306. McMillan Company, New York, London (1966) (10) T. P. Hoar and R. D. HoUiday, I. Appl. Chem. 3, 502-513 (1953) (11) Sieverts and Lueg, Zeitschrift anorg. Chem. 126, 193 (1923) (12) W.Kreutzfeld, Korrosion und Metallschutz 4, 104 (1928) (13) T. Hoar, “Proceedings of Pittsburgh Internat. Conference on Surface Reactions,” Pittsburgh, Pa. Corrosion Publishing Co. D. 121-134 ~.(19410 . ~, (14) ‘N. Hackerman and B. Markides, Ind. Eng. Chem. 46, 3, 523-527 (1954) (15) R. A. George and N. Hackermann, Corrosion, 11,6, 249t-254(1955) (16) H. L. Kahler and J. K. Brown, Combustion, 25, 7, pp, 55-58 (1954) (17) W. E.’Jones and I. P. Barrett, Corrosion, 11, 5 , 217t-220t (1955) (18) V. A. Kuznetsov and 2. A. Jofa, Zhurnal fiz. Khim. 21, 201 (1947) (19) 1. Worner, Trans. Amer. Electrochem. Sac. 55, 287 (1929) (20) A. Tile and C. Kayser, J. Phys. Chem. 170, 516,407 (1934) (21) N. Shilov, E. Shatunovskaia and K. Chmutov, Zhurnal phys. Chem. 149.211 (1930) , .~~., ( 2 2 ) L. K. Lepin, Usp. Khim. 9.5 (194) (23) M. M. Dubinin, Usp. Khim. 24, 5 (1955) (24) P. F. Cox, R. L. Every and 0.L. Riggs, Corrosion 20, 9, p. 299t-302t (1964) ( 2 5 ) N. Hackerman. R. M. Hurd and R. R. Annand. Corrosion 18. 1, 37t-42 (1962) (26) H. F. Finley and N. Hackerman, I. Electrochem. SOC. 107, 4, 259-263 (1960) (27) V. L. Stromberg, Materials Protection 4,4,6&64 (1965) (28) 3. G . Funkhouser,Corrosion 17, 6, 283t-287t (1961) ~~
This article is based on a paper that was presented at the 32nd Annual Meeting of the Intemational Water Conference of the Engineers’ Sociery of Western Pennsylvania, Pittsburgh, P a , Nov. 2-4, 19 71. APRILIMAY
KENNETH JURIS, Consolidated Edison of New York, lnc.
Simplified Meqod for Determining Tbwer Drift Rate \ A simplified method is outlined for determinin6 down flow is shut off, the concentration of dissolved solids increases; hut contrary drift rates kom cooling towers - both mechanical, and natural-draft - and spray ponds. The only'; to what one is reached at which the rate of msurements required me the dissolved solids con- '\,, drift equals the rate of discentration of the makeup water and hot water re- '.,,,dissolveds circulating back into the tower.
Closed-cycle cooling system. The blowdown flow is shutoff to determine the drift-rate from the tower, which is why the blowdown is shown here as a dotted line. When the blowdown is shut off, the dissolved solids concentration of 30
INDUSTRIAL WATER ENGINEERING
the recirculating water in the tower increases till it reaches a value C , at which point it levels off A t this point, the rate at which dissolved solids leave the tower iS equal to the rate at which dissolved solids enter the tower.