LIBRARY OF THE UNIVERSITY OF CALIFORNIA. Class The D. Van Nostrand Company intend this book to be sold to the Public at the advertised price, and supply it to the Trade on terms which will not allow of reduction BOILER-WATERS SCALE, CORROSION, FOAMING B7 WILLIAM WALLACE QHRISTIE M. Am. Soc. N. E., Consulting Engineer AUTHOR OF "CHIMNEY FORMULAE AND TABLES," "CHIMNEY DESIGN AND " THEORY," AND FURNACE DRAFT : ITS PRODUCTION BY MECHANICAL METHODS" SEVENTY.SEVEN ILLUSTRATIONS NEW YORK D. VAN NOSTKAND COMPANY 23 MUERAY AND 27 WARRED STREETS 1906 Copyright, 1906 BY D. VAN NOSTRAND COMPANY ROBERT DRUMMOND, PRINTER, NEW TORK 21 steam-boiler id a steam-generator, not a kettle for chemical reaction. "(Set, if possible, a supply of clean, soft, natural water." "lje onlg componno to jmt into a boiler is jmre water." , tlje most useful element, is, toljen free in boilers, a most bestrnctitJe corrosive element. 161878 PEEFACE. THE relative value of one boiler to another may, in many cases, be measured by its scale-forming propensity with a given water. Purify this water and all boilers come much nearer a uniform value per unit of heating-surface. This work has for its object to furnish steam-users with in- formation regarding water, its use, and troubles arising from the use of water, and remedies that may be used or applied; the gain being more efficient generation of steam. It is due to the Railway Master Mechanics' Association that real progress has been made in the softening of water for loco- motives, along which line much work is being done, and the same line of work is now being taken up by manufacturers and indus- trial corporations. The author wishes to thank all who have aided him in his work; credit has been given, as far as possible, to those to whom credit is due, and he sends the book forth as a pioneer on the subject in this country, and he will be glad to receive suggestions, just criticisms, and new material looking toward a more perfect and rounded-out work in the near future. WILLIAM WALLACE CHRISTIE. PATERSON, N. J., Oct. 1st, 1906. v TABLE OF CONTENTS. CHAPTER I. PAQB WATER, ITS PROPERTIES, MATERIALS FOUND IN WATER, WATER ANALYSIS 1 CHAPTER II. BOILER-SCALE TRANSMISSION OF HEAT-CONDUCTIVITY OF SOLIDS 39 CHAPTER III. CORROSION 68 CHAPTER IV. FEED-WATER PIPES BLOW-OFF PIPES TUBES 103 CHAPTER V. PRIMING AND FOAMING 117 CHAPTER VI. OIL GREASE ZINC 128 CHAPTER VII. HARDNESS OF WATER 142 CHAPTER VIII. FEED-WATER HEATERS ECONOMIZERS 1 54 CHAPTER IX. WATER-SOFTENING 1 77 CHAPTER X. MISCELLANEOUS TABLES 217 vii OF THE UNIVERSITY OF BOILER-WATERS. CHAPTER I. WATER, ITS PROPERTIES, MATERIALS FOUND IN WATER, WATER ANALYSIS. STEAM-MAKING is the important thing in all steam-plants; next in importance to the boilers themselves is the water to be evaporated as steam. Water is a combination of the two very abundant elements, hydrogen and oxygen, in the proportion of two parts hydrogen by volume to one part oxygen (H 20); it is also one part by weight of hydrogen to eight parts of oxygen. All living things, plant and animal, contain a large proportion of water. Water as used in power-plants is seldom sent to the boiler in a proper condition of purity, as is evidenced by the large number of boilers in which scale or corrosion is found. Distilled water should not be used unless a certain amount of raw water be added to it at regular intervals to prevent entirely or lessen its corrosive action. The most desirable feed-water is soft water, either that natu- rally soft or water that has been treated by one of the many methods of water-softening now in use, which destroy scale-forming proper- ties. Rain-water, a water we should think would come to us pure, is never entirely so, frequently containing one to three parts of inorganic impurities per 100,000 parts of water. 2 BOILER-WATERS. Snow and rain always contain gases of atmospheric origin, among which are oxygen, nitrogen, and carbonic acid.* Water Falling at Paris. Grams per Cubic Meter. Nitrogen. 6.397 7.939 Ammonia. 3.334 2.769 Nitric acid. 14.069 21.800 Chlorine. 2.081 1.946 Lime. ..... 6.220 5.397 Magnesium. 2.100 2.300 In addition to gases, we find in water the salts of ammonium, sodium, and calcium. Rain-water we may say in a general way is the purest of all natural waters. From seventy-one samples of water collected at a farm at Rothamsted, England, we have for an average: Total dissolved solids 3 . 95 Organic carbon . 099 Organic nitrogen . 022 parts per Ammonia . .050 00 Nitrogen as nitrates and nitrites .007 ' Total combined nitrogen 0.071 Chlorine . 063 From Massachusetts we have this analysis of polluted river- water : Turbidity slight Color 1.5 f Albuminoid ammonia . 263 ammonia 0.664 as *"*. Nitrogen j I Nitrites 0.025 [Nitrates 0.800 Chlorine 24 . 1 Total residue 127.0 All in parts per million. The waters of many rivers are contaminated with much coloring- matter and other organic matter in suspension, which can be readily filtered out and save much trouble in the boiler. * De La Coux, p. 8. IMPURITIES IN WATER. The same remark will apply if we leave certain organic matter in the water, as we shall see later is the case with river-water at Pittsburg, Pa. ANALYSIS OF WELL-WATER.* (U. S. Government Wells, Sandy Hook, N. J.) BOILER-WATERS. Spring-water, like well-water, is frequently impregnated with carbonic-acid gas, which comes from the organic matter in the earth. The water obtained from the granitic rocks is purer than that from the secondary strata, which latter is calcareous in its make-up. Unfiltered and filtered water may contain certain of the chemi- cal such as elements, sodium, calcium, potassium, etc., which re- main in solution at the ordinary or lower temperatures, but which decompose when subjected to the high temperatures from furnace- fires, and which elements fall to the shells or tubes of boilers as a fine powder or, what is more frequent, adhere to the tubes and shell as scale. Some contain zinc * for spring-waters ; example, one in southern Missouri has this analysis: Parts Parts per Millon. per Million. PbSO4 trace CaSO 4 109.9 CuSO4 0.5 MgSO4 19.0 CdSO4 0.9 K2SO 4 5.6 ZnSO4 297.7 Na2SO4 5.9 FeSO4 1.6 NaCl 4.3 MnSO4 . 6.3 CaCO3 72.0 A1 2 (SO 4) 3 2.5 SiO 2 13.7 Compressibility of Water. Water is but slightly compressible: for each foot of pressure distilled water will be diminished .0000015 to .0000013 in volume. At a depth of half a mile, 2640 feet, a cubic foot weighs only about one quarter of a pound more than at the surface. The freezing-point of water is at 32 F. at the ordinary at- mospheric pressure sea-level and ice melts at the same tem- perature. Sea-water freezes at 27 F., and the ice is fresh. The usual sources of water are: 1. Rain or melted snow; 2. Lakes, rivers, or creeks; 3. Wells, driven or dug; 4. Mineral springs; 5. Ocean- or sea-water; * Hillebrand, Bui. 113, U S. Geol. Survey. GASES IN WATER. and the forms of water commonly known to us are (a) Solid form Ice; (6) Liquid form Water; (c) Gaseous form Steam. Though water is used for domestic purposes, and for washing in in its broad sense, and to sustain life, it is only its use steam- boilers steam-making that we shall consider in this book. Peaty water from woodlands has a solvent action on lead pipes due to its acidify, which varies in terms of a sulphuric acid equivalent from 1 to 4 parts in 100,000. Mr. Ackroyd says that the solvent action would not occur if the acidity did not exceed 0.5 part in 100,000. High velocity of steam-particles is considered favorable to both corrosion and incrustation. Oxygen Dissolved in Water. Nearly all waters contain oxygen in solution. Spenmath states that water absorbs oxygen as follows: At 32, F. it absorbs 4.9 per cent of its own bulk; At 50 F. it absorbs 3.8 per cent of its own bulk; At 68 F. it absorbs 3.1 per cent of its own bulk. Stromeyer states that under 150 pounds pressure cold feed- water absorbs 3.2 pounds of oxygen per ton of water. ABSORPTION OF GASES. BOILER-WATERS. Gases were expelled from unit volume of water. Gases previously absorbed from the atmosphere at 54 F, Composition of gases: Oxygen 31, nitrogen 69 per cent. Barometer, 29.9 in. .000 170 180 1'JO 210 F. TEMPERATURE FIG. la. Temperature-gas-emission Curve. increased Temperature of water raised from 54 F., and steadily to 212 F. in one hundred and fifty (150) minutes. First evolution of gas at 120. econo- Mr. Smith says that "known facts relating to feed-pipes, SEA-WATER. mizer tubes, and those parts of boilers near the inlet amply prove that marked oxidation may ensue when the gases are released by temperature increment and whilst they still continue in a con- fluid flow in stricted ; contact with relatively large bounding super- ficies." - Atmospheric air contains only of carbonic acid, whereas the air held in solution in water contains from 40 to 42 per cent of carbonic acid. The boiling-point of water depends on the substances it contains in solution, or, in other words, depends upon its purity, also upon the atmospheric pressure or pressure in vessels containing the water.