PRODUCTION New Look at an Old Problem Pilot plant for "wet combustion" of sewage may show w a y around Chicago's disposal headaches J \ NEW WAY to solve the old problem of sewage disposal will get a trial in Chicago. A pilot plant t o study the Zimmermann "wet combustion" process will b e built for the Metropolitan Sani tary District of Greater Chicago by Sterling D r u g . The process was de veloped by Frederick J. Zimmermann, president of Salvo Chemical, Roths child, Wis., to reduce stream pollu tion caused by organic wastes. Salvo is a wholly owned subsidiary of Sterling, deals with the wood industry. In the Chicago pilot plant, the cost of burning sewage sludge in various concentrations—ranging from 2 to 6% or even more—will b e studied. These cost data, Sterling notes, should tell definitely how the Zimmermann proc ess stacks up against other sewage dis posal methods. H i e company has a research contract with the Sanitary District, which serves 104 cities and villages, including Chi cago, in a 900 square mile area. T h e r e are over 5 million people here; the industrial sewage load is equivalent to 3.5 million more. Under the contract, Sterling will take on all costs of con struction and installation and furnish operating personnel. This joint pilot-venture, says Ster ling, will show if the process can b e a d a p t e d to large scale sewage disposal. Until now, w e t combustion research has been devoted mainly t o eliminating stream pollution caused b y waste pulp
liquors and to converting the waste into steam or electric power. The Chieago study will not b e concerned with power generation. • How It W o r k s . T h e Zimmermann process is basically a burning in the presence of water. In Chicago's unit, sewage containing an average of 4% sludge (the remainder water) will be piped into a heat exchanger which warms the mixture. From t h e preheater, the h o t sludge flows into a pres sure vessel which acts as a reactor. H e r e , t h e sewage is raised t o about 6 0 0 ° F. while an air compressor pres surizes the reactor to 1000 t o 1500 p.s.i. T h e compressed air serves as an oxygen and heat source; sludge serves as t h e fuel. City engineers estimate that sludge can furnish from 7000 to 7 5 0 0 B.t.u. per lb. of dry s o l i d s enough, when the energy from the compressor is added, to make t h e proc ess close t o self-sustaining, Sterling feels. T h e process is continuous, and steam and ash are drawn off as they are formed. Part of the steam will be used to furnish heat to t h e preheater. T h e ash a n d remaining steam, after condensation, flow to a settling tank, from which the water can b e decanted into a lagoon. W a t e r disposal should offer no problem since it has an accept able biochemical oxygen d e m a n d . The small amount of nonoffensive ash can
f C0 2 AND NITROGEN OXIDES
AIR COMPRESSOR
UJ
PREHEATER
WATER
η f REACTOR FL·
SEWAGE SETTLING TANK
-™Ξ£ STEAM FOR PREHEATER
—
LAGOON ASH TO DISPOSAL
F r e d e r i c k J. Zimmermann's w e t combustion process for sewage disposal will get pilot plant trials starting this fall in Chicago. T h e process, which operates a t 6 0 0 e F . and 1000 t o 1500 p.s.i., is b e i n g developed b y Sterling Drug 68
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be d u m p e d at any waste disposal ground. Platinum reduces nitrogen connp o u n d s to oxides, w h i c h will b e vented into t h e atmosphere together with C 0 2 from t h e burning process. • Disposal E x p e n s i v e Now. Riglit now, the sanitary district uses t w o methods of sewage disposal. One is digestion. Sewage is piped into a tandc, where the solids settle and decay. R e sulting gases are vented. About o n e third of t h e district's sewage is treated this way, b u t t h e trouble here is that d i gestion destroys only about 30r/c of t h e objectionable material in sludge. T h e residue must be dumped, raising t h e problem of finding suitable dump ing grounds. The other m e t h o d used in the district consists of filtering t h e sludge by vac uum and flash drying the filter cake, T h e dry material is then shipped to southeastern states as a fertilizer. This gives complete disposal, but at a very high price. The money o b tained from sales of the dry sludge doesn't begin to pay for the operation itself, say district officials. But if tlie Zimmermann process proves successful, Chicago engineers feel that several units could be built around the county to supplement existing methods. The pilot unit will go into operation at the city's Southwest Works this fall. These are the key works in t h e treat ment system t h a t was acclaimed one of the "seven wonders of Amierican engineering" t w o years ago. A large commercial plant using the Zimmermann process is now going -up in Norway. H e r e , t h e process will con vert pulp liquors from Norway's largest p u l p p a p e r manufacturer into steam while eliminating pollution. T h e plant will b e completed next year, says Sterling.
Several Gases Will Do T h e nature of t h e working fluid has n o significant effect on efficiency of closed-cycle, gas turbine, nuclear power plants within t h e limits of our tests, reports S. T. Robinson of Ameri c a n Turbine Corp. Robinson tested helium, nitrogen, and carbon dioxide in comparable power plants t o check their effects on plant design. This means that any of t h e gases can b e used in nuclear power plants of this type. However, Robinson adds, the design of auxiliary e q u i p m e n t varies with the gas used—a helium plant, for example, would n e e d much less re cuperator surface t h a n a carbon di oxide plant, with other items sized accordingly. Robinson addressed the Gas Turb>ine Power Conference held b y AS Μ Ε in Detroit last week. ι
H^i&ft *•?**>-** ^?* jgff*-*g
α new Zow cosi infrared instrtiment
for the organic chemical lab oratory:
THE INFRACORD* DOUBLE BEAM SPECTROPHOTOMETER The new Infracord Spectrophotometer puts infrared analysis and its advantages within the reach of every laboratory. The result of a 4-year development program by Perkin-Elmer, the Infracord embodies the latest advances in optical, elec tronic, and mechanical design. A highly efficient double beam optical null system, previously available in only the most expensive spectrophotometers, provides the speed, energy, short path length and resolution so necessary for good qualitative and quantitative analysis. Rugged and compact, the Infracord as an every-day tool for the chemist gives him a fast answer and a permanent record of his work—at the bench. See the Infracord Spectrophotometer in Miami at the Hotel Fontainebleau, April 7 - 1 2 . Vincent Coates will be on h a n d to demonstrate the instrument at the ACS National M e e t i n g .
NOTE THESE FEATURES: • • • • • • • • • • •
d o u b l e b e a m measuring system atmospheric and solvent compensation differential analysis l i n e a r w a v e l e n g t h vs. transmittance recording b r o a d line o f sampling accessories single unit construction requires o n l y 120 volt, 6 0 cycle power source 2.5 t o 15 microns in 12 minutes instant w a v e l e n g t h reset d i r e c t recording on notebook size paper r e p r o d u c i b l e performance
PRICE: $ 3 8 5 0 . 0 0 f.o.b. Norwalk, Connecticut (in U. S. and Canada only) I N S T R
M E N T
Ο Ι V Ι S I ON
Pexrkin.-Hlxxi.er ύφvenation— Ν Ο R W A L Κ
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PRODUCTION
Briefs. . .
New Text
• Lion Oil, which recently brought in its first Canadian oil well (C&EN, Mar. 18, page* 9 6 ) , has brought in a dis covery well in Lafayette Parish, La. In its first tests, Tortue No. 1 produced 2.5 million cu. ft. of gas and 280 bbl. of 51.5° distillate per day through per forations nearly 11,500 ft. down. Lion Oil shares ownership in Tortue No. 1 with Texas Pacific Coal and Oil, Rowan Oil, and Rowan Drilling Co. • Quick freezes now come packaged in aerosols. Arco Electronics of Los Angeles has a new product, Jiffy Zero, which cools anything it is sprayed onto, is useful in checking faulty electronic circuits for the troublesome component. All you do, the manufacturer explains, is spray the svispected parts, one at a time until frost forms. If the circuit works when the part is frosted, you can be fairly sure that part is the faulty one. Chill ng agent is Du Pont's Freon. • Creslan, American Cvanamid's new
acrylic fiber scheduled for commercial production i n 1958, is readily dyed with a large number of dye classes, giving a n almost complete range of colors, the company claims. The dyed fiber is suitably fast to light, washing, perspiration, and crocking without loss of softness, strength, wrinkle resistance, and other properties, Cyanamid says. • Pressure b l o w e r installed at Liquid Carbonic by General Blower Co. has for five years handled 5000 to 10,000 cu. ft. per min. of 100° Ψ. flue gas containing SO._,, SO:{, N 0 2 , and water vapor, yet is still in perfect condition, according to General Blower. The blower shell is neoprene-coated steel; the outlet damper, Hastelloy C. • Force-length m e a s u r e m e n t s at a con stant rate of strain help to predict structural changes in plastics with time, according to I. J. Gruntfest of General Electric. One of the first uses pro posed by Gruntfest: get design data that could extend the use of plastics for structures.
Number 18 in ADVANCES IN CHEMISTRY SERIES edited by the staff of INDUSTRIAL AND ENGINEERING CHEMISTRY
THERMODYNAMIC PROPERTIES OF THE ELEMENTS Tabulated values of the heat capacity heat content, entropy, and free energy function of the solid, liquid, and gas states of the first 92 elements are given for the temperature 3 0 0 0 ° K.
range
298°
to
Auxiliary data include tem
peratures and heats of transition, melting and vaporization and vapor pressures. Published values analyzed and supple mented by estimates when experimental data are lacking.
Compiled by D. R.
Stull and G. C. Sinke, Dow Chemical Co. 234 pages - - - - hard bound
$ 5 . 0 0 per copy order from:
American Chemical Society 1 155 Sixteenth Street, N.W. Washington 6, D. C.
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Missiles by Chemical Milling More than 4 0 aircraft and aircraft parts companies are using North American Aviation's Chem-Mill process of etching metal. Large parts of stainless steel, titanium, and aluminum can b e chemically etclied to close tolerances, the company says. Now, what is reported to be the world's largest chemical milling plant for the manufacture of stainless and aluminum parts is in operation at North American's missile development division. T h e 36 X 130 ft. installation handles 4 X 12 ft. metal sheets formed to any shape and 30 ft. longerons to be tapered. Here, parts for Navaho guided missile are lo-wered into t h e etch bath.
