October, 1928
I&-D USTRl.4L AND ENGINEERING CHEXISTRY Summary
1-The aging properties of compounded rubber stocks are affected by the carbon black which is used. 2-The order of increasing superiority for the blacks tried is Super Spectra, Micronex, Charlton, Goodwin, and Thermatomic. &The order of increasing superiority of accelerators is diplienylyanidine, hexamethylenetetramine, ethylidene-ani-
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line, mercaptobenzothiazole. The last two are put in this order mainly because of the inferior original properties of ethylidene-aniline. 4-Results of tensile, abrasion, and weight increase tests are in reasonably good agreement. 5--The effect of acidity in any compounding material is neutralized in a stock containing zinc oxide. 6-Stearic acid is without effect upon aging properties of cured rubber.
Manufacture of Carbon Dioxide H. E. Howe
HIRTY tons per day of solid carbon d i o x i d e t h a t is one measure of the recently completed plant of the DryIce Corporation, erected near the line where the cities of Elizabeth and Newark, N. J., meet. Another indication of the size of ihis plant is that it consists of three units, whereas the largest previous installation has but two. It is therefore believed to be the largest plant at present in existence devoted t,o the mnnufacture of carbon dioxide.
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Elizabsfh. N. S., Plant of DryIce Corporafion. Absorption Towers in Foreground
for the production of carbon dioxide, clinker badly and at intervals the fire must be well cleaned. The admission of excess air a t such times reduces the carbon dioxide of the exit gases to 7 or 8 per cent, but this is for only a brief period. The high heat of the fires is also detrimental to the boiler setting and linings, even carhorundum brick requiring replacement about every 12 months. These conditions answer in part the question why carbon dioxide is not liquefied by power plants utilizing their stack gases. The remainder of the answer is found in the relation of power to liquefaction of gas mentioned above. The boilers used in this plant were manufactured by Urunswick-Kroeschel and are maintained at 150 pounds pressure. There is a damper in the stack which is open when the fires arc just started. It is then closed and a11 stack gases are conducted to the scrubbers, through which they are pulled by a Root blower and forced on to the hottom of the first absorber. The scrubbers are steel t,anks with limestone packing held on grids and under a distributing plate. These tanks are 7 feet in diameter by 25 feet ~ I Iheight, and about 25 per cent of limestone of the scrubber charge must be added annually to replace that consumed in the scrubbing process. Water is the principal scrubbing reagent, but some of the carbonate of the limestone is broken down, exchanging carbon dioxide for sulfur dioxide, which is thus removed from the passing gases. From the top of the first scrubber the gases are conducted to the bottom of the second. The water is circulated and there
Gas
Process of )Manufacture
The process adopted for the manufacture of the gas is the familiar one in which a low-sulfur metallurgical coke is the raw material. The coke in the process of combustion s u p plies the gas, while the heat generates the steam necessary for the operation of the plant. I n an installation of this kind it is always an economic question whether additional power can be used to advantage to liquefy gas beyond that which can be reduced to a liquid using only the power generated by the bnrning of the coke. Under careful control the stack gases can be made to contain from 16 to 18 per cent carbon dioxide. Theoretically 21 per cent is possible, but unless an excess of oxygen is present the sulfur becomes hydrogen sulfide and much carbon monoxide is formed. Both of these gases are wsstes in this process. Coke fires, managed to best advantage
“Snow Tanks” and Ice Molds
are the usual by-passes and connections to maintain the proper balance of the Worthington centrifugal pumps employed. The scrubbed gases now pass to the first of two absorber towers, these being of steel 10 feet in diameter and 105 feet in
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INDUSTRIAL A S D ENGINEERING CHEMISTRY
Vol. 20, No.10
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