Document L95OMv1JXGZJyzG55DzynNwz

FILE NAME: Oil Industry and American Petroleum Institute (API) DATE: 1947 Oct DOC#: API083 DOCUMENT DESCRIPTION: Trade Journal Article - What the Power Engineer Needs to Know about Heat Insulation ! I < Y. 110 EDITORIAL STAFF RALPH E. TURNER Editer ANDREW W . KRAMER Managing Editor CHESTER R. EARLE Associai* Editor THOMAS E. HANSON Sew s Editor GEORGE V. TEAL Associate Editor i * Pult'liilird Monthly by TECHNICAL PUBLISHING CO* 53 W . JACKSON BLVD. CHICAGO 4, ILL. KINGSLEV L. RICE, President EDWIN C. PROUTY, Vice President WALTER PAINTER, Vice President ARTHUR L. RICE, JR., Treasurer CHARLES S. CLARKE, Secretary JO H N O. AARVOLD, Prod. Mgr. i i DISTRICT MANAGERS CHICAGO: Charles S. Clarke Arthur L. Rice, Jr. $3 W . Jackson Blvd., Chicago 4, 111. Harrison 0824 PHILADELPHIA. PA, Charles A. Loncy 437 Riverbank Delanco, N. J. Riverside 4-0380M NEW YORK: Oscar Wilds Graybar Bldg., New York 17. N. Y. Caledonia 53779 CLEVELAND: A. H. Van Duyn 681 Union Commerce Bldg. Cleveland 14. Ohio Cherry 1377 PACIFIC COAST REPRESENTATIVES Roy M. McDonald & Co. San Francisco: Roy M. McDonald. Mgr. 564 Market St. San Francisco 4, Calif. Yukon 6-0503 Los Angeles ; Robert Aland, Mgr. 639 S. Wilton Place Los Angeles 5, Calif. Drexel 2590 Seattle: Harry Abney Terminal Sales Bldg. Seattle 1. Wash. Main 3860 WASHINGTON OFFICE Business Press News Bureau 1007 National Press Bldg. Washington, D. C. Subscription Information--Published Month ly. Prices: United States and Possessions * one year $10.00, Canada one year $11.00. Other countries one year $12.00. Single copies $1.00. Changes ol address should giv6 both old and new address and reach us by 15th of month to be effective wllh following month's issues. The Annual In dex is furnished as a part of the December issue. . ; ENGINEERING , October 1947 VOLUME 51--NUMBER 10 Engineer's Preview .......................................................................................................... 7 Helpful Bulletins ............................................................................................................. 35 N ew Equipment N ew s. .................................................................................................. 56 What Leaders Say............................................................................................................ 67 Power for Detroit Sulphite Pulp & Paper Co......................................................... 68 N ew Overcurrent Tripping Device for Low-Voltage Grcuit Breakers............ 71 By H. L. Rawlins and Jerome Sandin Corrosion in Boiler Feedwater Treating Systems-- 1............................................. 74 By Leo F. Collins Heat Insulation .............................................................................................................. 77 N ew Substations at Investment Savings..................... 80 By Marvin R, Kimbrell, Jr. Practical Engineer and Electrician.......................................................................... 83 Geiger Counter . ............................................................................. Atomics ........................................................................ Radioactive Isotopes as Tracers By Andrew IF. Kramer Stack Dust Collection and D isposal............................................................................ 108 By P. W . Thompson Aids for Small Business................................................................................................. 110 By Ralph E. Turner W hat Coal Fluidization May D o for the Power Plant of Tomorrow................112 By A. D. Singh How to Store and Handle Fuel O il..........................................................................118 By R. J. Bender Coming Events ............................................................................................................... 146 Obituaries ........................................................................................................................... 148 N ew s from the F ield ......................................................................................................148 Manufacturers' N e w s ......................................................................................................158 Manufacturers' Personal ................................................................................... , . . . . 1 7 2 N ew Engineering B ooks.............................................................................................. . 1 7 4 Catalog Library ............................................................................................................... 182 Construction N ew s ........................................................................................................ 200 Contenu of beck issues of Power Plant Engineering will be found in Industrial Arts Index on file in Public TJKwfi. Copyright, 1947, by Technical Publishing Company. E at*rod as ascend class m atter S eptem ber I, 1932 (original en try M ay 1, 1908L a t tb s Post fTffirt C hicago, HRnoia, m uU r aet of M arch t . 1879. October, 1947-- PO W ER P L A N T EN G IN EER IN G -C h lca go . III. 5 WHAT THE POW ER ENGINEER NEEDS TO KNOW ABOUT Heat Insulation Insulation a fairly modern problem . . . Even small boiler plants can show savings when insulation is intelligently applied . . . case study of a plant with one boiler given . . . Savings in one year amounted to $824.50 or nearly three times the total cost of the insulating job . . . Several suggestions given for retaining efficiency of insulation already applied . . . Moisture penetration one of prime enemies of insolation efficiency . . . Excessive vibration can quickly cause loss of efficiency K EEPING HOT things hot and cold things cold Is a problem which has plagued engineers only during the last few decades. Fuel costs have risen so tremendously and the cost of products produced by the heat have been subjected to such a terrific competitive struggle that tem perature has been turned into a pre cise tool--a tool that can be main tained only by the proper use of good insulation. Savings Not Conflnsd to Big Plants The savings, even in one-boiler plants, can be huge. One example, quoted by the Industrial Mineral Wool Institute, was found in a plant where the boiler was operating at a steani gage pressure of 120 psi and a temperature of 350 F. The boiler shell had an area of 400 sq ft. The particular plant in which this boiler was installed had been producing at capacity (it was thought) and it was obvious to everyone that new steam generating capacity would have to be installed if the new orders pouring in were to be taken care of. Someone had the idea that they might look into the possibility of i n - . sulating the boiler in order to provide just the additional amount of steam necessary to both take care of the new orders and also heat the build ing. A careful study revealed to the management that 2 in. of insulation on the boiler shell would increase to the amount necessary the quantity of steam availble. . Formala Used The method used to discover the approximate amount of insulation needed, the insulated heat loss and the savings in Btu was as follows. The formula for the heat loss of the pipe when bare was: the unit heat loss in Btu per sq ft per hour. (From Kent's pp 3-64) multiplied by the number of hours operated per year multiplied by the area in sq ft. In this particular case the formula looked like this: 798 Btu X 400 sq ft X 8,760 hr = 2.796.192.000 Btu per yr. For the heat loss from insulated pipe the fol lowing method was used: Unit heat loss in Btu per sq ft per hr through insulation of specified th ic k n e s s (Kent's, pp 3-67) multiplied by the number of hours operated per year multiplied by the area in sq f t This made the formula: 64 Btu X 400 sq ft X 8,760 hr = 224.256.000 Btu per yr. The savings in Btu were then cal culated by subtracting the number of Btu lost through insulated pipe from the number lost through bare pipe. This resulted in the following: 2,796,192,000 Btu minus 224,256,000 Btu = 2,571,936,000 Btu per yr. The conversion of Btu saved per year to fuel savings is made by di viding the number of Btu saved per year by the heat content of the fuel (estimated at 13,000 Btu per lb) mul tiplied by the operating efficiency. Or, as follows: 2^71,936,000 Btu _ 13.000 B tu/lb X 60% ~ 329,735 b 164.9 tons of coal saved per year. Similar calculations can be made for oil or gas. In this particular in stance, with coal at $5.00 per ton the saving amounted to $824.50. The total cost of insulating the boiler shell was $320.00, a cost of 80 cents per sq f t In other words, it took exactly 4.66 months to pay off the entire cost of insulating the unit ^Besides this not inconsiderable sav ing there Was also the added advan tage of having a boiler which was able to turn out the necessary addi tional heat without having to install new equipment The only question left for the management to ponder was why the boiler hadn't been In sulated many years before. Fig. 1. The insulation on the two companion flanges of this valve will permit maximum return on Investment. Insulating cem ent which is easily applicable on all irregular surface may be reclaimed for reapplication ' Rvtcrtalng E ittctoncr Simple suggestions for retaining the efficiency of insulation on pipes and flat surfaces, if followed, result not only in substantial savings but will Increase the life expectancy of October, 1947-- P O W ER P L A N T E N G IN E E R IN G -- Oiicago, III. 77 y: -.Th - TabU L Thi compilation ahow Um rscommsndsd Ihlcknsssss of minorai wool Insulation lor plp# coring ju se and is only recommended for ir regular surfaces where it is not prac ticable to apply formed materials. Steam Pressure or Condition Temperature Thickness of Insulation Pipes 5 in. and Larger Pipes 4 in. and 4% in. Pipes 2,2% , 3 and 3% in. The accompanying tables present information on recommended thick nesses of insulation for pipe covering and for flat surfaces and have been compiled by the Industrial Mineral Hot W a te r ................... 1 1 1 0 to 25 lb ...................... 212 to 267 F 1 ^1 1 25 to 100 lb ...................267 to 338 F 1 1 1 100 to 200 lb .................338 to 388 F 1% 1 1 Low S u p erh e at........... 388 to 500 F S u p erh e at..................... 500 to 600 F 1% 1% 1 2 _ 1% 1% High Superheat and Hot Oil Lines 600 to 700 F 700 to 800 F 800 to 1000 F 2 2 1% 2% 2 2 3 2% 2 Note: For outdoor piping increase thickness % in. For underground piping decrease thickness % in. Wool Institute. . : '. There are many places In the power plant where the advantages offered by properly applied insula tion will far outweigh the cost of material and application. One of the least spectacular of these and yet one which will pay the handsomest re turns are the many flanged joints which have been left bare in a good many plants. both insulation and equipment. A waterproof jacket properly applied on pipe lines which are exposed to the elements will protect both piping and insulation. This same jacket should be used on inside lines where they are exposed to splashing from process water or other forms of continuous wetting. Insulation also should be protected from moisture entering from the pipe side. Moisture penetration from pipe lines carrying low side refrigerant or cold water can be partially prevented, at least, by sealing the insulation on the pipe side. This requires a more thorough job of sealing than does outside wa ter and weather-proofing. Such lines, when once sealed, should be inspected regularly to make certain no cracks or openings have developed. When pipe repairs are made re place all covering as carefully as though the entire job were brand new. Make certain that the insula tion fits snugly around the pipe. Loose pipe covering will increase the heat loss and may be damaged much more easily than snugly fitting mate rials. In many processes insulated pipe lines may be exposed to strong add or alkali fumes. Jackets are avail able which will protect the pipe and In one instance reported by the painted with asbestos cement Re IMWI there were ten sets of 6 in place and paint the canvas. If can companion flanges with a bare sur vas Is not available apply asphalt- saturated felt jackets carefully wired and then cement the laps and joints with lap cement. face area of 1.82 sq ft each. Steam was passing through ' the lines at 350 F. Two inches of insulation was applied. The cost of insulation, in W ater hammer, remote as it may seem to some, may be caused by in sufficient or inefficient in s u la tio n . Even if the insulation is not the cause of the water hammer once the cause has been discovered and corrected cluding some outside weatherproof ing, came to $3.00 per flange or a total of $30.00 for all ten. It was later calculated that this seemingly trivial job was saving up to 7 tons of coal per year. inspect all insulation for damage. Duct Insolation The impact of the hammer may open Everyone recognizes that proper cracks in the covering. Another fruit ful source of trouble with insulation dyct insulation cuts fuel and energy can arise when leaks occur in steam costs, prevents heat from radiating or water lines. Steam impinging on into or being absorbed from work pipe covering may cause rapid dete areas, and makes possible greater rioration. W ater from a ,le a k may control over heating and cooling sys follow along a pipe for a consider tems. able distance, saturating the covering ' imBpuotrtannocte eovferfyoollnoewinregcopgrnoipzeers atnhde and thus destroying almost all of the insulating value. At times this has tested installation techniques. Time- been known to cause the insulation tested and approved steps are de to fall completely off the pipe. scribed to be followed in applying mineral wool insulation to ducts are When workmen or maintenance described in the following: crews are working about the plant The three general duct usages do not allow them to load the insu lated pipe lines in any manner. Scaf folding, walkways made of boards, etc., may distort the insulation even if it does not crack it outright Dis tortion will cause the air cell struc insulation by resisting these fumes. ture in the insulation to be icomSuch fumes may easily destroy can pressed thus materially reducing its vas and holding wires or bands and efficiency. The best way to discover allow the covering to fall from the pipes. Under some conditions the acid fumes may actually attack the insulating materials. for yourself, or to prove to some one else, the efficiency of air space as an insulator is to sit on a pipe carrying high temperature steam and which is Excssslvs Vibration Another thing which can bring about short-insulation life on pipe lines is excessive vibration. Elimi nate or minimize all vibration by proper hangers, springs, etc., as con stant shaking and jarring may cause joints to open or may reduce the effi ciency of the insulation by some other means such as packing. Signs of failure in canvas coverings are often times due to the pipe covering loos ening from the pipe. When this hap pens the covering should be carefully wired back in place and the joints insulated with a resilient insulation.' The hot seat is an effective convincer. Bedadng. Waste One means of reducing waste is to grind and mix broken pieces of magnesia pipe covering or blocks with water for use as a patching cement The resulting product is usable but, of course, will not compare in effi ciency with the material in its orig inal form. Do not, however, use ta bulating cement in place of blocks o r. pipe covering as it is nowheres near as efficient. Insulating cement has been developed for a particular pur- Tig. 2. This photo shows ths manner oi reinforcing tbs c o res oi ductwork InsulaHot by us# oi mstal angles 78 October, 1947-- P O W ER P L A N T E N G IN E E R IN G -- Chicago, III. Tabla IL Hecommanded thicknesi oi min erai wool insulation for flat surfaces are giren in this table Operating Temperature Degrees F 100 to 200 201 to 300 301 to 500 501 to 700 701 to 900 901 to 1100 1101 to 1200 Thickness inches 1 in. 1% in. 2 in. 2% in. 3 in. 3% in. 4 in. which require insulation are 1) car rying hot gases, 2) carrying air for room heating and air conditioning, and 3) carrying cool gases. Insula tion of ducts used in ordinary room heating is primarily valuable in pre venting heat from being dissipated before reaching its destination. When cool air or gases arc carried in in sulated ducts, the additional annoy ance of deteriorating condensation sweating prevented. Operating ex pense, of course, is a factor in every case. For inside installations, where the temperature gradient is not great, the following procedure is recom mended: 1) Clean the duct of all grease and dirt. 2) Cut mineral wool blocks to conform to the area to be insulated. 3) Wire the blocks to the ducts. Galvanized or expanded metal angles are recommended to keep the blocks in line at the corners, as shown in Fig. 2. When the temperature gradient is greater than that encountered in room heating and air conditioning ' additional steps are advised. As illus-' trated in Fig. 3 they are: 1) Trowel a xh in. coating of mineral wool in sulating cement over the surface of the blocks; 2) Follow this with a layer of 1 in. mesh poultry netting; Fig. 3. Tb* various l a r t n oi insulation material aro shown here. They are: in sulating cem ent 1 in. poultry mesh netting and a Vi in. coating oi WnUMng cement 3) Apply a Vi in. coating of finishing cement ,, . In cases where the contents of the duct are a t a lower temperature than the surroundings, an asphalt or other type of vapor b anter must be applied to the insulation exterior. The pur pose of the vapor barrier is to pre vent atmospheric moisture from per meating the mineral wool and con densing therein, thereby spoiling its insulating qualities. Asphalt, is also useful in cementing the mineral wool blocks to the duct before wiring them WHAT IS THE ANMB DOING? (Continued from page 67j parts required both in the actual fab rication o i the products and the tool ing necessary to produce the products. Naturally the standby facilities which were operated in World War n form an important consideration in this phase of the planning. It has been determined that approximately 100 plants should, if enabling legisla tion is enacted by Congress, continue to be government-owned. There should also be a number of govern ment-owned plants released for sale with what is termed the "National Security Clause," a clause inserted in the lease which provides for a claim upon the plant on the part of the Secretary of W ar and/or the Secre tary of the Navy in case of an emer gency. . In addition to the industrial pro duction required, there is the prob lem of setting up certain agencies necessary to handle production of goods that might be utilized by the armed services and production of goods that are absolutely necessary for the civilian economy. In addition to this, we are emphasizing over everything we have, the need for a constant revision not only of this phase of the industrial mobilization plan but of all phases. We have a saying in our shop that we will write the 1947 Industrial Mobilization Plan and the minute it is finished we will start on the 1948 Plan; and it is our hope that this will be <jone every year of our country's life. The eco nomic situation changes and the po litical situation changes, the weapons change, and any plan of this sort must be written with these changes in mind. The Industrial Mobilization Plan will be revised in the light of a changing situation as weapons be come obsolete and new ones will take their place. To illustrate, if the future plane is going to use a fuel entirely different from octane gas, our plants making such gas become obsolete and plants capable of producing the new fuel become all-important. We would like to have such a plan each year read and noted as pro duced and would welcome comments from the President of the United in place, and for preventing corro sion. Commandai Standards Good practice in the installation and use of insulating materials has been published in Commercial Stand ard CS117--44 issued by the U. S. Department of Commerce nd avail able for 10 cents from the Superin tendent of Documents, Washington, D. C. This standard has been volun tarily accepted by a large number of the leading associations and com panies in the country. States, the Secretaries of the serv ices, heads of important departments of the country, such as Commerce, In terior, etc., and by the heads of the military committees of the Senate and Congress, To us, this seems very Important in keeping the responsible administrators of our country familiar with what is going on and with the opportunity, as the plans are formu lated, of making whatever comments seem best to them in light of current conditions. Our schedule or "time table" of preparations may be divided into three different phases:. (1) The work that should be done in peacetime pre paring the plan to meet an emer gency; (2) the actions and steps that will be necessary from the time trouble might appear until it actually descends upon us; (3) the setting into action of all the necessary agencies, bureaus, production, etc., when trou ble has actually descended upon us. As I have previously stated, an effec tive industrial mobilization plan must be a plan by representatives of all Americans. Thus the Board has de veloped a program of industry ad visory committees to assist in the dis cussions and preparation of the plan. The Board is trying to visualize a set of conditions that may be ahead of us. No one can possibly write a master plan today which would be effective 25 years from now, but we do believe it possible to write a plan today that could go into effect next year. I emphasize the importance for men of industry, men of science, and the administrators of our country to realize that any Industrial Mobiliza tion Plan must be a changing one, reviewed and revised in the light of current thinking. I ngots of m etal that take pictures of themselves are produced by West inghouse scientists who inject doses of radio-active atoms into steel, and other alloys. The tagegd atoms shoot out rays and particles at a photo graphic film. The resulting pictures showing the the position of the atoms are helping determine the causes of rust and brittleness. . October. 1 9 4 7 -P O W E R P L A N T E N C IN E E R IN G -C h ic a g o , III. 79