776
INDUSTRIAL AND ENGINEERING CHEMISTRY
Vol. 23, No. 7
combustion chamber accords well with the idea that the emission is by carbon dioxide heated by the increase in pressure brought about by combustion of the rest of the charge.
cules as those which give off light during the reaction between carbon monoxide and oxygen. At present it' appears probable that carbon dioxide molecules are the emitters.
Conclusions
Aclrnowledgments
The principal facts that have been established by this study are as follows: 1-The visible light emitted by the flame fronts of benzene and gasoline burning in an engine under non-knocking conditions comes largely from C H and Cz molecules. These spectra are similar to those of inner cones of flames of the same fuels burning in an ordinary blast burner. 2-When the engine is knocking, the C H and Swan Cz bands appear very feebly in the visible region of the spectra of flame fronts in the detonating zone. However, the spectra of the flame fronts prior to the beginning of knock exhibit both the C H and the Cz bands with intensities comparable to non-knocking explosions. 3-Addition of lead tetraethyl to the gasoline suppresses knock and reestablishes CH and Swan CZbands in the spectra of the flames in the detonating zone. &Lead is present in the flame fronts in the detonating zone as atomic lead and molecular lead oxide (PbO). &The afterglow spectrum is emitted by the same mole-
The writers take pleasure in expressing their appreciation to T. A. Boyd and E. J. Martin for active cooperation and helpful advice throughout the course of the investigation and during the preparation of this manuscript. Literature Cited (1) Bloomenthal, P h y s . Rev., 35, 34-45 (1930). (2) Clark, J . SOC.Automotive Eng., 23, 167-73 (1928). (3) Clark and Henne, I b i d . , 20, 264-9 (1927). (4) Clark and Thee, IND.ENG.CHBM.,18, 528-31 (1926). (5) Johnson and Asundi, Proc. R o y . SOC.(London), Al24, 668 (1929). (6) King and Birge, A s t r o p h y s . J., 72, 19 (1930). (7) Kondratjew, Z . 'Pltysik, 63, 322-33 (1930). (8) Maxwell and Wheeler, J . I n s t . Petroleum Tech., 14, 175 (1928): IND. ENG.CHEM.,20, 1041-4 (1928). (9) Pretty, Proc. P h y s . SOC.London, 40, 71 (1927). (10) Shea, P h y s . Rev., 30, 825 (1927). (11) Thee, J. SOC.Aulomoliwe Eng., 26, 388-92 (1929). (12) Weston, Pmc. Roy. Soc. (London), A109, 176 (1925). (13) Withrow and Boyd, IND. END. CHEM.,23, 539 (1931). (14) Withrow, Lovell, and Boyd, I b i d . , 22, 945 (1830).
Economies of Tank Insulation'
M
ANY industries use tanks containing hot liquids for process as well as for storage purposes. Because of excessive bare-shell heat losses such tanks are often inefficiently operated. Some of these tanks are in buildings, while others are out in the open, exposed to the weather. I n either case proper insulation will materially reduce heat losses and greatly improve the temperature control. This report describes an actual case where insulation on exposed steel tanks containing hot creosote has effected a fuel saving of 12.3 per cent. Insulation has reduced the coal consumption sufficiently to make the installation extremely interesting from the standpoint of the return on the investment. It is also possible to get better temperature control during cold weather. The operating data and information herein presented on the direct benefits of insulation were compiled in collaboration with the National Lumber and Creosoting Company a t their Finney, Ohio, creosoting plant, where about a million railroad cross ties are treated each year. Ties treated here are cut from native hardwoods. The firm, with headquarters in Texarkana, Ark., operates eight creosoting plants located in different parts of the country. The equipment a t Finney consists of a boiler house, three storage tanks, four working tanks, and two treating cylinders. Two SO-horsepower boilers supply steam a t 110-pound pressure for the entire plant. Steam is passed through heating coils in different parts of the creosoting process to control the creosote temperatures. Steps in Creosoting of Railroad Ties Creosote, received a t the plant by rail, is transferred to three large storage tanks, each 24 feet in diameter and 16 feet high, which stand on the ground out in the open. These This report was prepared by the Johns1 Received April 27, 1931. Mansville Corp. in collaboration with and approved by J. H. Bade, superintendent at the Finney, Ohio, plant of the National Lumber and Creosoting
co.
tanks act as a reservoir and supply the working tanks with creosote for treating the ties. Temperature control in the storage tanks is relatively unimportant. During the cold weather submerged steam coils heat the creosote to permit pumping from one tank to another. Cold creosote is pumped periodically from the storage to the working tanks to keep them filled to within about a foot of the top. There are four such exposed working tanks, each 16 feet in diameter and 24 feet high, supported off the ground by steel work. They are termed "working tanks" because hot creosote, heated by submerged steam coils, is pumped directly from them into the treating cylinders and back again. The two tanks most frequently used are the ones which are insulated. Continuous temperature recorders are employed to enable the men to maintain the creosote temperature a t about 200" F. a t all times. The ties are treated in two large horizontal treating cylinders, each 6 feet in diameter and 132 feet long. Narrowgage tracks located inside extend the entire length of the cylinders. Untreated ties are loaded on tram cars and are pushed into the cylinders, each of which, when fully loaded, holds about 500 ties. After they are loaded, large cover plates are placed over the open ends and firmly bolted t o the cylinders. Creosote is then pumped from a working tank, a t a temperature of 200' F., to fill the units completely. Steam is passed through coils in the cylinders to compensate for any temperature drop due to the cold charge of ties and radiation losses from the shells. After a treating cylinder is filled with creosote, a pressure ranging from 175 to 200 pounds per square inch is maintained for about 8 hours, At the end of this period, which of course varies somewhat for different woods, the creosote is pumped back into the working tanks and the treated ties are removed. To compensate for the creosote absorbed by the ties, each working tank requires a make-up from the storage tanks of approximately 6000 gallons of creosote per day.
'
Part of the Sforspo Yard s t Pinney, Ohio, Where Untreated 'Ties Are Slacked Prior to Creosotinp
Applicatiun of Insulation on Working Tanks
The sidcs and tops of the two working tanks were insnlated during tho latter part of 1925.2 A '/l-iuch layer of asbestos sir cell was first put over the top of the tanks, and a 3/&nch layer of hair-felt insulation wae then spot-mopped to the air cell. A waterproofing jacket, consisting of one layer of double-c.oat.ed Fiexstniie, was spotmopped to the hair-felt insulatinn and then the entire t.op was mopped with asphalt.
jacket was then spot-mopped to the hair-felt insulation. The vertical joirrts in the waterproofing jacket were covered with I/g X 2 inch iron batten strips held in place with nine '/,$ X 2 inch irori bauds running circumferentially around the tanks. The insulation on the sides of the tanks was supported with curved circumferential angles spot-nclded on 6-foot centers (vertically). At times creosote is spilled and nms down the outside of the Flexstone jacket, but this has no apparent effect upon the insulating material? wliich at the time of writing are (May, 1931) completing years of service and are still in excellent condition. Savings Effected by Insulation
Th
