December, 1923
INDUSTRIAL A N D ENGINEERING CHEMISTRY
Internal Treatment of Boiler Water-Proper
1239
and Improper'
By D. I(. French D ~ A R B O CHEMICAL RN Co., CHICAGO, ILL
b o i 1e r problems involve scale formation, corrosion, and foaming-all serious and worthy of investigation and treatment for their control or elimination. Scale formation seemingly has attracted the most attention, possibly because its manifestations are most easily observed and its treatment follows more common chemical knowledge.
R
BUGHLY,
SCALEFORMATION
The use of lime and soda ash has been general for years, but knowledge of the defects of the process is eauallv general. Both carbonate of lime and carbonate of magnesia are soluble after even the best adjusted lime additions. Furthermore, in practice these reactions are far from theoretically complete, owing to the presence of other salts naturally in water. Stein2 and Sperry3 agree that ideal conditions rarely follow such treatment in practice, and stress the importance of certain assisting reactions. In the boiler, however, reactions take place rapidly and a t high pressures are very complete, as a result of which there is almost no water that will not form some scale, even after the best outside treatment, as most incrustants are pretty nearly insoluble at 100 pounds steam pressure. While outside treatment is clarifying the water, it is also removing certain impurities which in the boiler might react to decrease the very definite crystalline character in which these same incrustants will deposit and cement on the heating surfaces. Organic and vegetable matter will not react in the cold-in fact, it will hold back precipitation. In the boiler the results are quite different, and while its precipitating value is not high, it changes the boiler medium sufficiently to prevent crystalline separation and causes the deposition of the scaleforming salts in a largely amorphous condition. This amorphous precipitate is easily in%uenced by boiler currents, so that, instead of settling immediately, these impurities circulate under such conditions as to make possible the collection of a very large percentage, if not all, in mud drums or similar devices designed for just such purposes. From the mud drum the precipitation can be removed as easily and more completely than in the case of previous outside treatment. While this means complete precipitation in the boiler, it eliminates feed-line stoppage, pump troubles, etc., which invariably follow an incomplete or poorly adjusted outside treatment. With a carefully calculated concentration of organic materials in the boiler, crystalline separation can be prevented, and while the sludge may be objectionable, its removal is much easier than that of the crystalline deposits. -
I
1
Received July 31, 1923.
8
I b i d . , 6, 215 (1919).
Furthermore, economy in precipitating chemicals is possible if the balance between them and the controlling organic matter is properly adjusted. A case in mind is that of a large municipal plant using Missouri River water. The incrustants vary from 12 to 16 grains per gallon, including 2.5 to 5 grains of calcium sulfate. Treatment is adjusted so that the dosage per 1000gallons of water contains barely 25 per cent of the necessary reacting chemicals. These reagents are combined with organic materials, however, in such a wav as to result in the existence at all times of a water in the boilers from which calcium sulfate is completely absent, in which the carbonates are reduced to 1.5 grains or less, and which contains a 2 to 5-grain excess of originally added reactive alkali. When properly diluted in the feed water, the chemical reactions are retarded, while boiler temperature and pressure effect most of the precipitation, under such control, however, as to make possible the continuous and complete removal of the sludge long before it has been allowed to assume a crystalline condition. Organic matter, properly applied, also has the effect of slowly changing old crystalline deposits to a less compact and more easily disintegrated form so as to make possible its slow removal without discontinuing boiler operation. Such organic reactions as occur usually produce bulky precipitates relatively light for their bulk, which, while continuing to circulate, seem to have coagulating and clarifying properties. I n this way, finely divided suspended matter which might otherwise be found later in scale is removed. Other chemicals exist, not of an organic character, which have this same effect and can be used satisfactorily when conditions indicate the undesirability of adding organic matter to the boiler. Silicate of soda is such a material, and it is frequently sold as a boiler compound. Used alone, its efficiency is very low. Furthermore, its action is very little understood, as most silicate of soda compounds are claimed by their sellers to treat the metal and not the water. For internal treatment there exists an almost unlimited variety of combinations which can be adjusted either to react directly or, as is more apt to be the case, to take advantage of what the boiler is doing. By thus assisting and controlling precipitation it is possible with a small amount of material to bring about conditions which would require many times that quantity if added outside for visible purification.
Up to the present time all discussions of the treatment of water supplies for industrial purposes have been limited to reactions which occur at atmospheric pressures and at temperatures below that of boiling water; yet no such discussion can be complete without consideration of what is known as internal freatment applied directly in the boiler for the correction of the dificulties encountered in steam production. The lack of discussion of this phase of water treatment has been caused largely by the confusion in the minds of fhose interested with regard to properly and thoughtfully applied treatment wifhproprietary compounds for which marvels are claimed. I n the boiler itself, where temperatures and pressures are much higher than those under which the ordinary water-softening processes operate, reactions occur which may or may not be the same as those occurring outside the boiler. These reactions have been given careful study by the author of this paper, and the observations gleaned from the practical application of this method of treatment are set forth in the accompanying article. I n addition to the principles on which such treatments act. the author discusses at some length the proprietary compounds which have done so much to discredit this method of treatment.
* Y. A m . Waler Works Assoc., 6, 202 (1919).
CORROSION Corrosion is a type of boiler trouble which is more easily controlled through internal treatment than is scale formation. Outside treatment increases, rather than decreases, the natural corrosive tendency of a water, through the re-
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I N D U S T R I A L A N D ENGINEERING CHEMISTRY
moval of certain protective i m p ~ r i t i e s . ~Frequently, outside treatment increases noticeably the soda salts, which, while not corrosive of themselves, will soon concentrate sufficiently to make possible distinct electrolytic corrosion. Dissolved gas is also an active cause of this type of trouble. While lime can remove dissolved carbon dioxide, none of the known inorganic treating chemicals seem to have any effect on dissolved oxygen. However, the alkaline tinnates, properly adjusted, have the property of combining with these gases, especially oxygen. Organic acid compounds added to high concentrations of alkali first cause a reduction of the excess alkali, retarding the possible tendency toward caustic embrittlement, and then in the alkaline combinations act both as an absorber of corrosive gas and an interfering agent in connection with probable electrolytic corrosion. Where organic materials cannot be applied, the chromates and dichromates are frequently used, though the amount necessary to get results in an operating boiler is usually too high for economy. Corrosion is frequently attributed to magnesium sulfate, magnesium chloride, calcium nitrate, etc., and as a rule when these salts exist in any material quantity the pH values are very noticeably below 7.0, and sometimes below 6.0, without any free acidity. Properly adjusted chemicals introduced into the boiler are much more effective and their neutralizing value is higher than when the same reactions are carried on outside at normal temperatures. The effect of alkaline tannates in reducing the corrosive value of concentrated soda salts can be demonstrated by measurement of the hydrogen-ion concentration, as well as by chemical examination. The composition of water from the boiler after varying periods of operation, when using organic types of treatment, cannot be even approximated volumetrically as the organic matter present interferes with ionization or produces less active addition products of salts which would cause trouble largely in proportion to their activity as inorganic impurities.
FOAMING A third type of trouble is foaming. Again internal treatment properly devised and applied has produced remarkable results, whereas outside treatment, aside from clarifying a water, has invariably stimulated, if not actually created, a tendency to foam. Foaming has been variously attributed to sodium and potassium compounds in concentrated solutions, suspended matter, organic impurities, boiler construction, and uneven load and pressure. The latter two factors no doubt stimulate the trouble, but the whole problem is one of surface tension, increased as the dissolved salts increase in concentration, and complicated by operating conditions and the physical character of the mater. A muddy water may steam quietly, and a clear supply may foam beyond control. However, anything which will lower surface tension without creating complications will reduce foaming. On the same basis, clarifying of the water is also a help. Suspended matter provides the nuclei for steam bubbles which, if not able to break easily through the surface film, will raise the water level to a dangerous degree. Soluble inorganic salts and some organic compounds toughen this surface film, and the most serious foaming follows a combination of the two conditions. Outside treatment offers absolutely nothing to control this trouble. On the other hand, any outside treatment using soda in any form tends to stimulate foaming through the 4 Clark and Gage, “Studies of the Relative Corrosion of Metal Pipes by Waters Especially before and after Purification,” 42nd Annual Report, Mass. State Board of Health, 1911. 6 Cushman and Gardner, “Corroslon and Preservation of Iron and Steel,” p. 100.
Vol. 15, NO. 12
increased amount of soda available for concentration. Moreover, the acknowledged incomplete precipitation of the carbonates of lime and magnesia ultimately furnishes suspended matter to increase steam bubble formation in even the clearest water. I n the field of orgonic internal treatment it is possible to produce and use compounds that will not only destroy the tenacity of the surface film, but ‘supply a form of organic coagulant which will readily clarify the water and definitely retard foaming. It is a well-known fact that castor oil alone of all the animal and vegetable oils possesses properties which, released under proper conditions, have a marked effect in controlling this trouble. The result has erroneously led to the impression that the use of oils, mineral as well as saponifiable, would stop foaming. This is not the case, as oil of any kind, as such, will invariably increase, rather than decrease, surface tension. Castor oil alone, or with improperly selected materials added, is absolutely without value; properly combined, the results are immediate and effective. In one particularly recent case of an enormous plant where an antifoam preparation was used following preliminary treatment and filtration through a treating plapt, it was estimated that on the initial introduction of this material a t a time when the boilers were all consistently foaming, the water level in the boilers fell, on an average, three feet. I n several cases it was shown that there was so little water actually in the boilers in question that the fires had to be drawn to avoid the possible danger of explosion which would follow. In this connection it might be stated that, combining precipitation outside with an antifoam treatment inside, boilers can use even the poorest water with a fair degree of satisfaction. Organic acids, free or in combination, also have a distinct effect in controlling foaming, and there are many cases where they are more effective than the type of treatment already discussed. Sometimes the composition of the water indicates that coagulation alone will take care of the foaming tendency, and in such case the coagulant must be carefully selected to avoid hardening, or making the original supply more corrosive. Frequently, a water which shows no indication whatever will foam, and then operating conditions, possibly contaminated returns, or boiler construction must be investigated. Uneven load, forced boilers, and careless attention can be followed by unexpected difficulties along this line, and often these can be corrected and the boilers operated safely without the otherwise necessary treatment. Foaming is a trouble which it is impossible to control permanently in some cases, owing to the fact that inorganic concentration is faster than the treatment. Nevertheless, the use of a properly adjusted preparation to control foaming will almost invariably, even with indifferent attention, extend operating periods without trouble two or three times beyond what might previously have been the custom. Aside from indicating what has been done and what can be done, the discussion of interior treatment is a difficult one. In many cases results are being obtained for which the real reason, of theory, is still uncertain, and one of the greatest handicaps is the difficulty of even approximating boiler conditions for research in a laboratory. Experimental work a t atmospheric pressure is misleading, as well as work on one available supply only. Interior treatment, properly applied, calls for an enormous amount of data, experience, and imagination. Knowledge of the chemical composition of the supply or supplies in use represents only one of the necessary factors to be considered, and internal treatment, while flexible and easy of application,
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December, 1923
INDUSTRIAL A N D ENGINEERING CHEMIXTRY
1241
will not give the best results unless based upon thorough knowledge of each individual case. Disregard of this need for careful study of each case has resulted in the preserrt lack of consideration of this whole field by the scientists who might otherwise be working toward efficiency in the industrial world of power production. Probably more plants are operating with the assistance of some treatment or compound than with all the other types of water purification combined. Such a fact should stimulate research into the underlying theories involved. Unfortunately, it has not, probably because, while intelligent introduction of adjusted treatment can produce results of the highest type, this field is infested with a type of material which borders so closely upon the mysterious, impossible, and uiiscrupulous as to place it in the same category as the patent medicine in its particular field.
Silicate of soda in its proper place in mater treatment has a very definite advantage, but to dodge the necessity of water examination and chemical adjustment by ignoring the boiler water, and to argue as in the three quotations above is to take the first step away from the legitimate use of this chemical and place it in the class of fakes. This type of compound was brought to the attention of the GovernEent several years ago, when it was operating the railroads, and a test was made, covering a period of several months, to determine to what extent the claims as to mechanical action, scale prevention, corrosion prevention, etc., were borne out in practice. A portion of a sentence from the Government’s conclusion, in a bulletin issued by the U. S. Railroad Administration, August 29, 1919, is quoted:
BOILERCOMPOUNDS The widespread use of inadequate or unfit boiler compounds is no doubt due to the fact that the salesmen of boiler compounds do not, as a rule, come in contact with the purchasing departments. Rather they visit the tired, discouraged, and sometimes not over-educated boiler operator, who would give a great deal if some of his boiler-room troubles could be overcome. That of scale formation and scale removal is one which bothers him the most frequently. The many varieties of compounds which are offered in this way vary all the way from preparations containing 98.5 to 99 per cent of water to others carrying 96 to 98 per cent of insoluble siliceous material. For these materials various claims have been put forth, playing upon the hope as well as the credulity of the engineer, or his ignorance of scientific facts, and it is the purpose of this paper to call attention to the types of unscrupulous compounds or some of the methods used to advertise them. M E r A L TREATMENT TYPE-& the present time probably one of the most common types of preparations is that of the so-called metal treatment which we will call “A.” This material is invariably of the same or similar composition; in other words, it is always a solution of silicate of soda in water, the greatest variety of dyes and chemicals being used to color and disguise the individual compound. All colors of the rainbow are used-even fluorescein, in one case--to give a two-colored product. The claims all read about the same:
beneficial results were concerned, it is recommended that the use of this product * * * be prohibited.
In view of the facts that none of the claims advanced in favor
of this preparation have been substantiated, and that the results obtained from the test were negative, in so far as any
IKSOLUBLE TwE-Leaving the metal treatment, possibly the next most interesting type to consider would be the “DD” compound. This preparation appears in several forms, with arguments especially interesting and amusing. This type of preparation is almost entirely insoluble in water. As one bulletin says: It is a nonvolatile and neutral combination of insoluble earthy salts.
Another bulletin says: The material is a combination of nonsoluble powders which are also nonvolatile.
One eminent chemist says: It is a dry powder and therefore you are selling 100 percent material.
Analysis shows this type of material to be either tricalcium phosphate, talc, aluminium phosphate, or some similar insoluble compound. As to its action, the theory in one bulletin is most amusing:
I n another booklet covering Metal Treatment “B” is a
Now the theory is this : In the case when scaling water is used and when “DD” is not used, the instant that water is transformed into steam the various salts held in solution are transformed into gases, and after flying apart seek to readjust themselves in combination, and look for an affinity or some other salt to amalgamate with. In so doing certain salts, part of which become gas, seek an oxide of iron and oxide of alumina salt or gas. Not finding this in the water and finding it in the steel and iron of the boiler sheets and tubes, it fastens to the sheets and tubes and pulls therefrom such oxide of iron and oxide of alumina that it craves, forming what i.; commonly known as scale, and leaving holes commonly called pitting. “DD” material furnishes to the water these required salts and the detrimental salts or gases amalgamate with, or eat them instead of the tubes and sheets. In other words, “DD” material is a “food.”
story, and in this story occurs the following statement: That soft lime and sulfate crust that I used to be fighting all the time is porous and has little heat cracks in it I put this stuff
In another article advertising the material recommended by the eminent eastern chemist, comparing compound with “DD,” there appears something as follows:
Boiler Metal Treatment “A” does not treat the water. Its action is mechanical, not chemical. When introduced into the boiler it immediately enters every pore and crevice in the scale and literally elbows it from the metal by its expansive quality, which is about 20 diameters.
in. The stuff warms up and heads straight for the hot iron in the tubes and shell. It seems to work right through the pores of the scale and when it gets next to the hot metal the stuff begins to swell like a “poisoned pup” and pries the scale off.
Wiih regard to Metal Treatment “C:” Remember this metal treatment does not treat the water; it has to insinuate itself through the cracks in the scale all over the boiler surface.
To a chemist this is a pretty clear fake. Silicate of soda is applied as a solution of a soluble alkali salt in water, and when added to any water the solution becomes more dilute, rather than acting as a gum-shoe artist. In the breaking down of the sodium silicate, the alkali (NasO) acts like a reduced quantity of caustic soda with the coagulating properties of the free silicic acid added.
“Compounds” depend largely upon tannates, caustic (or sal) soda, and other like ingredients to do the work. These various acid ingredients work behind the scale, often attacking the metal *. The action is too severe, for the scale breaks up in large, flint-like chunks.
Regarding the use of the material the following is quoted: This powder is put into the boiler and is carried in rapid circulation to every part of it, bringing the scale down in soft particles. It catches up the oil, so that when the boiler is blown most of the impurities are blown out in the form of a soft sludge. It is possible with the naked eye to distinguish the various elements forming this sludge.
The truth of the matter is that nothing whatever can be expected of a chemical nature from this material. Where it has given results-and it does give results in isolated
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INDUSTRIAL AND ENGINEERING CHEMISTRY
cases-it has probably been because the insoluble inert material, by mixing with the scale-forming salts which are constantly crystallizing in the boiler, may prevent the compact formation of an all-crystalline scale, thereby rendering its removal with a turbine somewhat less difficult. However, it is a thoroughly good insulating ingredient, and it can do no more than increase the bulk of the scale in which it is incorporated, and, unless the scale does come off for some reason or other, it must of necessity increase its insulating properties. With this particular type of compound must be classed graphite. This material is what its name indicates, nothing more than commercial graphite. Very frequently some additional geographical term precedes graphite, evidently to increase the value of the material. The same claims are made for graphite as are made for all boiler compounds, and frequently following its use conditions develop which seem t o indicate some possible efficiency. However, in an article on boiler compounds appearing in the Journal of the American. Society of Naval Engineers in 1911, this material is classed under a special heading of “Dangerous Compounds,” owing to its distinct corrosive action on the metal. Iron is very definitely electropositive to graphite. This results in the solution of the iron without any action on the graphite, and it is possible that this corrosive action is responsible for the scale removal which frequently follows the introduction of this material. As the article just referred to says: Graphite is a scale remover for the same reason that hydrochloric acid is. That is, it corrodes the metal underneath the scale and frees the scale from the metallic surfaces.
Obviously, being insoluble in water, it can have no other effect than a possible mechanical action in keeping apart or interfering with the crystallization of other deposited impurities into a compact scale. It will, however, add itself t o the bulk of scale formed, retaining a t all times its electronegative effect to the iron as long as the boiler is in operation. Possibly, the next type of material would be the so-called “X” liquid treatment. This is a sort of homeopathic remedy and contains more water than anything else. It is named usually with interesting foreign scientific names, and its introduction is frequently preceded by a newspaper article (advertisement). For instance, in a New York paper some years ago appeared a special dispatch from Vera Cruz regarding a remarkable discovery by a young Spaniard after much study and experimenting, ending with the statement that the discovery is patented in “seventeen different countries.” The analysis of a sample of this material reaching this laboratory showed 98.5 per cent of water. The solution was slightly acid and a faint test for tannin was detected. There seemed to be some gelatinous material present and little or nothing of any value could be detected. Another preparation was heralded by a booklet explaining the remarkable properties of a colloidal jelly which was embodied in this solution. The analysis showed 88.5 per cent of water, 6 per cent of soda ash, and 6 per cent of a gelatinous material like agar. On standing in the laboratory the material soured rapidly and fermented. Newspaper articles almost invariably credit the discovery of this material and similar preparations t o some point in Mexico or Central America. It stands to reason that, used in small quantities in the boiler, no possible improvement could be expected. Furthermore, the expense would not permit a larger dosage, as the material just referred to is quoted a t about $1.25 a gallon. Granting some colloidal action from the 6 per cent, or less, of organic material, this would only apply to an infinitesimal portion of the scale-forming impurities carried into the average boiler.
Vol. 15, No. 12
Before leaving this “X” type, the writer recalls a preparation of several years ago. The advertising matter pertaining contained the picture of a very exuberant goat, and the preparation, upon analysis, turned out to be a diluted, blue-black, iron-tannin ink, there being about 0.75 per cent of tannate of iron with a little chrome alum and over 98 per cent of water. These two types of compound, all insoluble and mostly all water, represent the extreme cases of fraudulent compounds. The materials present could have no value under the very best of conditions, and their cost has no relationship whatever to their value. There is a large intermediate class, as well, some of which, under certain conditions and if intelligently used, might give results, but in most cases, where used hit or miss, the same material in the same quantity with all waters, the results cannot help but be discouraging and tend t o upset any faith in the intelligent internal use of chemicals for boiler treatment. RESULTSOF LABORATORY ANALYsIs-This laboratory, since the first of the year, has analyzed eighty-six entirely different boiler compounds which represent the average of what is now being marketed. Twenty-two represent the metal treatment type and three the insoluble type. I n the all-water group are included such compounds as contained 75 per cent or more of water, and of this particular type fourteen samples were received. These fourteen samples might be classified as follows: those containing soda ash as the other ingredient totaled seven, from 10 to 13 per cent soda ash being present, the balance being usually coloring matter, as a rule organic extract, although amorphous carbon was used in one case; those containing organic matter only, usually a very dilute tannin extract, totaled five; a suspension of graphite in water, containing nearly 25 per cent of graphite and 75 per cent of water; and one containing 4 per cent of organic matter and 5 per cent of trisodium phosphate. These preparations are manifestly worthless and yet in no case were they marketed for less than 15 cents per pound. The other extreme is the preparation containing mostly soda ash. Soda ash, being cheap and reacting quickly with sulfate of lime, has always been a favorite with the compound quack. It can be bought with or without water of crystallization, and costs very nearly the same in either condition. Of the samples analyzed, nine of the eighty-six were of this character, containing 80 per cent or more of soda ash, the difference being coloring material, sometimes with a little caustic soda, and the ordinary impurities of a commercial product. These preparations are all guaranteed t o prevent scale and eliminate corrosion under all conditions. I n one case a company handling an almost pure soda ash, save for a slight color, advertised that this compound was a by-product of a very intricate method of organic manufacture, and later advertising matter states they have been compelled to greatly enlarge their plant to cover several additional acres, owing to the demand for this remarkable product. I n addition to the straight soda ash is the preparation which masquerades as soda ash but which is not. I n other words, the washing soda, preparation containing 45 t o 52 per cent of water of crystallization, the balance being carbonate of soda with natural manufacturing impurities. Here for the same price one gets but half such efficiency as might be had from soda ash. Trisodium phosphate, commonly used many years ago, does not seem to be so generally marketed as it was, although two samples of this material were analyzed. While this is an efficient chemical if properly used, its 50 per cent water of crystallization must not be overlooked, nor the fact that its reactive value is less than that of soda ash.
December, 1923
INDUSTRIAL A N D ENGINEERING CHEiMISTRY
Next .worthy of consideration comes the compound supplied in brick form. I n this form the intention is evidently to give the impression of solidity. I n this case advantage is taken of the fact that carbonate of soda can exist in a dry (?) form, both with water of crystallization and without. Consequently, by bringing together soda ash and tannin extract and allowing a portion of the materials to become pretty well mixed, the resultant compound can be left alone with perfect confidence that, when cold, its physical condition will be that of a hard, brown-colored brick, in which the original soda ash exists partly as such and partly as the carbonate of soda containing more water of crystallization. A great many samples of this sort of material come into the laboratory. Since the first of the year out of fourteen samples received, all but one contained soda ash as the reacting chemical and tannin extract. The soda ash content ran all the p a y from 34.5 to 75 per cent, the water content varying from 35 per cent down to about 14 per cent. The balance was usually organic matter, although some of the bricks contained graphite. I n addition, one contained 17 per cent of sulfate of soda; one, 30 per cent of sulfate of soda; one, 4 per cent of metallic mercury; two, less than 10 per cent of sodium phosphate; one, castor oil; and one contained silicate of soda, trisodium phosphate, and caustic soda in addition t o the soda ash and organic matter. One of the most typical, which we will call “OU,” was described in a booklet containing some of the most remarkable arguments ever advanced in handling a boiler compound. Quotations from this booklet are illuminating :
\
The secret process by which “OU” compound is made lies with the inventor, and that secret will not be detected by any chemist or school chemistry. Chemists are like all other human beings. They know a great deal, but they do not know everything. They know what they have been taught in school, but the teachers of the school in which they received their educations learned everything they knew from their predecessors and from experiments with what had already been invented. When different kinds of chemicals, which are required to neutraliz,e minerals in water, are mixed together, they will neutralize each other and therefore become ineffective and will not neutralize the minerals which are contained in water, and for that reason those who have attempted to make a boiler compound from the knowledge they received in chemical schools have made a failure, and for that reason also, we were compelled, in order to make good boiler compounds, to invent and create chemicals or certain kinds of material which are not known to chemistry.
One of the most popular liquid preparations contains from 17 to 19 per cent of caustic soda in water colored brown. This is sold in huge drums, and even tank cars, a t a price all out of proportion to its caustic content. Its popularity is largely due to a personal financial rebate made the purchaser. Paste preparations appear on the market containing sometimes 85 per cent of water with enough starch to thoroughly gelatinize the mixture and make it seem very hard, heavy, and honest. Ordinary common salt is a frequent adulterant. Two samples analyzed showed 41 and 45 per cent of common table salt. Powdered mixtures sometimes contain, in addition to soda ash and other chemicals already referred to, sodium sulfate. Probably this is to keep the preparation dry. I n connection with all these preparations, it must be remembered that each one is a specific recommended for virtually all sorts and conditions of water. OTHER“TREATMENTS”-One or two other methods of treatment, fortunately not now in general use, must not be overlooked. Several years ago, through Germany and Great Britain came an equipment known as “Luminator.” Chemical Abstracts at that time summarized the theory and operation as follows:
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Water allowed to run down a bright corrugated AI plate induces an electric current, which causes ionization of the scaleforming salts so that they become amorphous. The apparatus must be exposed to light and air and preferably t o a north or south light for best results. Water treated by this process should be used within seven days.
Strange to say, this equipment was actually sold and installed in a great many American plants, one large eastern railroad putting up a unit 15 to 20 feet in height. Needless to say, the flow of the water down the corrugated plate in the bright sunlight was never followed by anything more than profanity. Another type along the same line is entirely mechanical. It is: Done without the introduction of chemicals within the water or boiler. * * * It is a machine of an extremely sensitive alloy of pure metals. This machine is attached to the feed water line of a boiler, or battery of boilers, and all of the water must pass through the machine before entering the boiler. The action of the machine causes a liberation of fine particles of the metal to enter the water through the abrasion of its parts. These fine particles a t once attack the scale forming minerals and salts, thereby preventing them from cementing themselves together or to the iron of the boiler. The principle involved is very simple and is readily understood. * * * The iron of a boiler is a metal, made up for durability. “Our machine” is a very pure, soft metal. * * * It has a greater affinity for the scale-forming elements, which will naturally attach themselves to the pure and more sensitive metal rather than to the iron of the boiler. No analysis is required, as “our machine” treats all waters.
The equipment consisted of a metal chamber containing a number of white metal balls, seven or more, around which the water flowed. Chemical analysis indicated the balls to be nothing more than Babbitt metal, practically all of the same general composition. Needless to say, these arguments are not borne out. The water does not do what the claims indicate, and mental depression only follows the use of this material.
THETRUTH ABOUT BOILERCOMPOUNDS A consistent and earnest reading of the patents on compounds registered a t the various patent offices is amusing. There is no specific that can handle all conditions. It is only the ignorant demand for the millennium that makes possible the life of such preparations. A moment’s thought should be enough to convince one of the impossibility of getting something for almost nothing, although very frequently a great deal is paid for trouble. The fact should never be overlooked that these various chemicals, when used, all do something when brought in contact with the salts naturally present in the water. In certain cases some of these combinations unquestionably would represent the proper material for use. Many of them, used with intelligence, would produce satisfaction. I n no case, however, is there shown any effort on the part of the manufacturer to adjust chemical treatment to any individual water, and the advertising matter and arguments show such ignorance of chemical facts as to suggest the impossibility of the average compound manufacturer even knowing what he is doing. The firms which are treating water thoughtfully by this method do not give their materials fancy names, nor call them compounds or specifics. They refer to them as “treatment,” and recommend a treatment with discretion. The success and magnitude of the results obtained through internal treatment indicate the efficiency of a properly recommended and manufactured chemical treatment used inside the steam boiler. The United States Government in its Water Supply Papers has been in the habit of indicating this fact, but always with the qualification that only when intelligently recommended and compounded should confidence be placed in the boiler compound.
