JUNE, 1939
INDUSTRIAL AND ENGINEERING CHEMISTRY
that observations in suitable testing boilers show the absence of mists. He assumes that salt dusts resulting from the evaporation of droplets of boiler water are in the steam. Apparently the presence of mist in the steam is determined by the experimental conditions. That the mists observed in the present investigation were not always salt dust is proved by their being present when distilled water was in the boiler. No attempt a t measuring the effect of these mists on carryover was made. Such effect must, however, be very small.
Conclusions The results of this investigation show that in every case gross carry-over was caused by foam that reached and covered the steam outlet. Since the two boilers differed so widely in design and were operated a t different pressures, this fact seems significant and suggests that more emphasis should be put on the study of foaming conditions. Since the maxima observed occurred a t concentrations of dissolved salt above that in commercial boilers, no estimate of the practical value of this property of boiler water can be made a t the present time. Some observations are also recorded on the appearance of the foams on the boiler waters, and on the presence of mist or fog in the steam space in the boilers. No conclusions can be drawn from these observations, however, because no connection between them and the extent of carry-over could be noted. The old question also comes up as to whether the behavior of the water in a commercial boiler is the same as that of the
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water in these experimental boilers, and again the old answer will be given. Only a long series of experiments with commercial boilers could determine whether the behaviors are the same, but it does not matter; because the main object of work with experimental boilers is to suggest newaideas to the operators of commercial boilers.
Acknowledgment Grateful acknowledgment is made of the many courtesies of The Ohio State University Research Foundation, of The Ohio State University Engineering Experiment Station, and especially of the generous financial aid from the National Aluminate Corporation.
Literature Cited (1) Cassidy, paper presented at joint meeting of the Engrs.’ SOC. West. Pennsylvania and Pittsburgh Section of Am. SOC. Mech. Engrs., Pittsburgh, Oct. 15, 1935. (2) Christman, Holmes, and Thompson, IND. ENQ.CHEM.,23, 637 (1931). (3) Eberle, Arch. WiZrmewirt., 10, 329 (1929). (4) Foulk, IND. ENG.CHEM., 16, 1121 (1924). (5) Foulk, J . Am. Water Works Assoc., 17, 160 (1927). (6) Foulk, Trans. Am. SOC.Mech. Engrs., RP-54-5, 105 (1932). (7) Foulk and Groves, IND. ENQ.CHEM., 25,800 (1933). (8) Foulk and Miller, Ibid., 23, 1283 (1931). (9) Foulk and Ulmer, Ibid., 30, 158 (1938). (10) Foulk and Whirl, Ibid., 26, 263 (1934). (11) Hancock, personal communication. (12) Jakob, Max, Mech. Eng., 58, 643 (1936). (13) Joseph and Hancock, J . SOC.Chem.Ind., 46, 315T (1927). (14) Stumper, Wtlrme, 59,478 (1936). ENG.CHEM.,Anal. Ed., 9, 172 (1937). (15) Ulmer, IND.
Electrodeposition of Lubricants from Aqueous Dispersions Electrodeposition is effective as a means of forming or depositing lubricant films on wire or other metallic surfaces. Whether or not enhanced lubricant results from electrodeposition depends largely on the physical nature of the deposited film.
T
HE field of lubrication as applied to metal-forming operations affords examples where the application of relatively thick films of solid lubricants is advantageous (1). Thick films of lubricant are commonly applied to metal sheets, rods, or other shapes by spraying, brushing, or dipping p r e paratory to drawing. The investigation of drawing lubricants for such forming operations also involved the study of various factors concerned with the use of soap solutions and fat emulsions (8). It was shown that adsorption, broadly, was responsible for the lubricating action of a soap solution when wire was drawn through a die immersed in or bathed by the solution. It appeared that film formation by adsorption of the dispersed lubricant phase might be aided by setting up an electric field where the wire would be the anode in the case of negatively charged lubricant “particles.” A preIiminary report on electrodeposition has already been published (3).
ROBERT C. WILLIAMS The Ironsides Company, Columbus, Ohio
Apparatus and Procedure Measurement of the pull on the wire-drawing die provided a means for the evaluation of the factors involved in lubrication as influenced by electrodeposition. The apparatus consisted of a glass tube, 11.4 X 2.2 cm., which was clamped horizontally against the die holder (Figure 1). The tube acted as an electrodeposition cell. The wire passed through the lubricant solution contained in the cell prior to being drawn through the die. A carbon electrode was inserted through the rubber stopper. The distance between the carbon electrode and the wire was 0.9 cm. Storage batteries supplied d. c. voltage up to 30 volts. A resistance placed in parallel provided a meens for varying the voltage. Contact with the wire was made by clamping onto the steel dynamometer plate. An ammeter registered the current flow. The lowest current density calculated was of the order of 0.019 ampere per sq. cm. (0.003 ampere per square inch); the highest was 1.05 amperes er sq. cm. (0.16 ampere per square inch). The polarity o?the wire could be changed at will, depending upon the charge possessed by the dispersed lubricant. In the experiments reported here, the wire was the anode.
INDUSTRIAL AND ENGINEERING CHEMISTRY
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lubricant must melt or be trmsformed to a fairly mobile liquid between the surfaces while shearing takes place. Copper soap made from CARBIDE DIE a fatty acid of 40.8 titer satisfies these conditions. The above experiments were repeated but the pH of the 0.225 per cent sodium soap solution was varied by adding hydrochloric acid to decrease it and sodium hydroxide to raise it. These results are shown in Table 11. It is not difficult to exdain the rather remarkable results in Table I1 i n the basis of previous work done on the admixing of fatty acids and copper oleate where the waxlike copper oleate lost adhesion and consequently enhanced lubrication was not obtained. In fact, precipitated copper oleate heated to 100" C. for 15 minutes decomposed to form sufficient fatty acid to prevent good adhesion of the copper oleate to the wire. The sweating out of an oily phase from an otherwise waxy solid does not permit enhanced lubrication, since adhesion to the wire is lost. In the experiments (Table 11) it is believed that simultaneous deposition of fatty acid as such (by electrophoresis) a t the lower pH values likewise adversely affects lubrication by the copper soap. At pH 11.8 the evolution of oxygen gas a t the wire, as a result of relatively high hydroxyl ion concentration, caused a disruption of the film of copper soap and probably accounted for erratic results. The study of the effect of pH on the lubricating effectiveness of soap solutions (%')showed a gradual decline in lubricating effectiveness as the pH was raised to the vicinity of pH 12; a t this point there was a sharp decline which resulted in no lubrication whatsoever as the pH was still further increased. As pH was increased, in these experiments, there was a beneficial effect until gassing (oxygen) was pronounced. This would be expected with the repression of hydrolysis as pH was increased and a consequent reduction in free fatty acid. No substantial effect on the repression of ionization of the sodium soap was experienced, judging by the deposition of copper soap which presumably requires the existence of fatty acid radical ions. As a control experiment a sodium hydroxide solution of pH 12 was electrolyzed. The wire was drawn with great difficulty, seizure occurring spasmodically.
. --TUNGSTEN
COLLAR ./
FIGURE1. APPARATUS FOR EVALUATING FACTORS INVOLVED IN LUBRICATION
ctf
4 /-
The die holder was mounted in the calibrated dynamometer, previously described in detail (W), and consisted merely of a rigidly mounted, deflectable steel plate. Deflections measured in thousandths of an inch registered the entire pull on the die. A given deflection represented a pull of so many kilograms or pounds. The speed of draGing was $0 em. (approximately 1 foot) per minute, unless otherwise indicated. Die pull in these experiments was independent of the speed of drawing from 1 t o 100 feet per minute. The back pull necessary t o keep the wire taut was slightly less than one pound and was also kept constant in the experiments reported here. Fresh solutions were used for each reading, because the capacity of the cell was so small that impoverishment would result in prolonged runs. The percentage reduction in pull on the die refers to the ratio of the pull with the applied potential to the pull, using the lubricant bath with no potential applied. The percentage reduction would be much greater if the pull with the applied potential were compared t o the pull with no lubricant.
1
Electrodeposited Films The effect of the electrodeposition of lubricant from a 0.225 per cent solution of sodium soap with a pH of 9.5 (from fatty acid of 40.8 titer) on the drawing of 0.0253-inch soft copper wire, through a 0.0225-inch tungsten carbide die is shown in Table I. OF LUBRICANT FILMS TABLEI. ELECTRODEPOSITION
Volts
Ampere
o/ Reduction in gull on the Die
1.0 1.9 3.75 7.5 15.0 22.5 30.0
TABLE11. EFFECTOF PH O N LUBRICATION BY SOAPSOLUTION SUBJECTED TO ELECTRODEPOSITION % Reduction in Pull on Die
When the voltage was impressed sufficiently to cause an appreciable current to pass through the cell, a pronounced reduction in pull was effected. Simultaneous with current flow, a greenish coating, visible to the naked eye, was deposited on the wire. At higher voltages the pull on the die decreased further. It is believed that the lubricating film, deposited on the wire in these experiments and primarily responsible for the enhanced lubrication, was copper soap formed by the union of the fatty acid radical ions and copper ions from the wire. I n the earlier paper (1) dealing with waxlike lubricants, copper oleate was also effective; it was pointed out that three conditions relative to the unusual effectiveness of wire drawing lubricants must be satisfied: (a) The lubricant must adhere strongly to a t least one of the surfaces-the wire or the die; (b) the lubricant must be solid prior to being subjected to the relative'shearing of the surfaces to be lubricated; (c) the
5
Volts 1.0 1.9 3.75 7.5 15.0 22.5 30.0 Erratic.
pH 7.5 6 8 10 100 105
..
0
pH 9.5 0 29 29 33 36 38 40
pH 10.2
pH 11.8
ii
ii
30 46 46 46a 46a
41 44 44 44 445
TABLE 111. EFFECTON LUBRICATION OF THP ELECTRODEPOSIBEESWAX FROM EMULSION CONTAINING 0.9 PER CENT WAXAND 0.15 PERCENTSODIUM SOAP(PH 9 PLUS)"
TION OF
a
Volts Ampere 0,001 1.9 0,004 3.75 0.009 7.5 15.0 0.024 0.054 30.0 All tests drawing 0.0253-inch soft copper wire.
% Reduction in Pull on Die 35 37 39 40 36
INDUSTRIAL AND ENGINEERING CHEMISTRY
JUNE, 1939
Table I11 presents the results with a beeswax emulsion in the cell. Favorable reductions in pull were observed. When 15 volts were used, the actual pull in pounds was the lowest observed in any experiment reported here. Beeswax was the most effective waxlike lubricant tried under the similar conditions reported previously (1). Unlike fatty acid which was also simultaneously deposited (Table 11), beeswax augmented efficiency because of its adhesive nature and typical waxy properties. Beeswax stably emulsified with soap is not particularly effective in reducing die pull. It is apparently not adsorbed readily. Electrodeposition of tallow from an emulsion containing 1.4 per cent tallow and 0.2 per cent potassium soap (pH 8.6 to 10) gave no enhanced effect under conditions identical to those in Table I. Here, as in the case of the soap solution containing appreciable quantities of free fatty acid, the waxlike nature of the copper soap was changed by the tallow. A rather heavy coating of tallow admixed with the greenish copper soap was readily observed, however. Emulsions of tallow in soap solutions have never shown any
727
advantage over soap solutions alone in this experimental device without the electrodeposition procedure. With 0.1 per cent sodium stearate (pH 9.9) no enhanced lubrication was observed and no visible deposition of green copper soap was noted a t room temperature when currents up to 30 volts were used. When the temperature of the solution was raised to 75” C. so that the sodium stearate “dissolved” and subsequently ionized, enhanced lubrication did result and copper stearate was formed in visible quantities. Regarding the time required to deposit an effective film from a soap solution such as is described in Table I, 0.1 second is sufficient. Thus commercial drawing speeds should offer no particular difficulty, if we take into consideration an electrodeposition “cell” of reasonable size. The original electrodeposited film is carried through three to four dies with a measurable lessening of die pull.
Literature Cited (1) Williams, R.C.,IND.ENQ.CHEM.,27, 64 (1935). (2) Williams, R.C., J.Phus. Chem., 36,3108 (1932). (3) Williams, R.C . , Wire & Wire Products, 12,754 (1937).
Reaction of Carbonic Acid with
the Zeolite in a Water Softener ROY E. KING
0. M. SMITH
Panhandle Power and Light Company, Borger, Texas
Oklahoma Agricultural and Mechanical College, Stillwater, Okla.
S
INCE the commercial introduction of the zeolite method or base exchange of water softening, it has usually been
considered that the only exchange reactions occurring were those involving the basic ions. Although Riedel (2) in 1909 described the reaction of dissolved carbon dioxide on zeolites, comparatively little consideration has been given to the basic properties of the hydrogen ion. I n this paper we show, as softening proceeds, that there is a gradual decrease in alkalinity with the formation of hydrogen zeolite, which subsequently exchanges its hydrogen ion with basic ions and thus forms free carbon dioxide and lowers the p H of the efluent water. Two stations of the Panhandle Power and Light Company are supplied by deep well water having an analysis similar to that shown in Table I. The only significant difference is STATION TABLEI. ANALYSISOF WELLWATERAT JOWETT P. p .
m.
Total solids a t 103” C. Total hardness as CaCO3 Total alkalinity
319 206 190
Silica FetOs and AlzOa Calcium Magnesium Sodium Bicarbonate Carbonate Chloride Sulfate Nitrate Carbon dioxide
24.8 1.2 73.0 6.0 26.2 232.0 0.018.0 33.0C 17.7 15.0
Grains/gal, 18.7 12.0 11.1 1.45 0.07 4.27 0.35 1.53 13.55 0.00 1.05 1.93 1.03 0.88
that the water a t Jowett Station, near Mobeetie, Texas, contains 15 p. p. m. of carbon dioxide, whereas the water used at Riverview Station, near Borger, Texas, contains 7 p. p. m. Because of the low sulfate-carbonate ratio the boiler feed water was treated a t Jowett Station with sulfuric acid prior to softening, and a t River view Station with acid following the softening. The total alkalinity of the water was reduced from 190 to 25 * 5 p. p. m. At Jowett Station it was observed that no matter how narrow the range of alkalinity in the influent to the softener, there was always a wide variation in the total alkalinity of the effluent.
Cause of Variation in Alkalinity of Effluent investigationwas made to determine the extentand the cause of these variations. The usual methods of operating the water softener were followed. The total alkalinity of the influent and effluent during the softening period is shown in Figures 1 and 2. I n the beginning the total alkalinity of the effluent was much higher than that of the influent but gradually decreased as the softener became exhausted, until it was less than that of the influent. In following the idea that dissolved carbon dioxide in the water might be responsible for the observed changes, tests were made in which the quantity of free carbon dioxide was compared to the total alkalinity in the influent and effluent waters. Typical data from one of these tests are shown in Figure 1. The influent was untreated Jowett Station water with a free carbon dioxide content of 15 p. p. m. Similar
