BRIEFS Summary of papers published in this month’s research quarterly, IG’EC Process Design and Deuelopmeni

THE COEFFICIENT OF KINETIC FRICTION FOR DOWEX 50 ION EXCHANGE RESIN MOVING DOWN A GLASS COLUMN. COMPACTED BED

For Dowex 50 ion exchange resin, coefficient of kinetic friction data were obtained from the movement of a compacted bed down a glass column through countercurrently flowing water. A variable- weight piston forced the resin down the column. Coefficient of friction values ranged from 0.011 to 0.048.

Daniel Hershey, University of Cincinnati, Cincinnati, Ohio, and Fred N. Peebles, University of Tennessee, Knoxville, Tenn. IND. ENG. CHEM., PROCESS DESIGN DEVELOP. 3,l-3 (1964)

THE COEFFICIENT OF KINETIC FRICTION FOR DOWEX 50 ION EXCHANGE RESIN MOVING DOWN A GLASS COLUMN. NONCOMPACTED BED

For Dowex 50 ion exchange resin, coefficient of kinetic friction values were obtained from measurements of the drag force on a thin-walled smooth metal cylinder supported from a spring scale. The noncompacted bed of resin moved downward, past the cylinder, and was subjected to a countercurrent water feed stream. The coefficient values ranged from 0.0026 at fluidization to 0.0068.

Daniel Hershey, University of Cincinnati, Cincinnati, Ohio, and Fred N. Peebles, University of Tennessee, Knoxville, Tenn. IND. ENG. CHEM., PROCESS DESIGN DEVELOP. 3,3-4 (1964)

MIXING TWO FLUIDS IN A CLOSED CONDUIT

The problem of mixing two fluids, such as gas and air or hot water and cold water, in a desired ratio in closed conduits is studied. An ejector-mixer of suitable geometry can be made to improve the stability of the mixture ratio under fluctuating supply pres- sures. Equations are developed, and verified experimentally, which enable the proportions of an ejector-mixer to be calculated for optimum performance under given conditions.

A . K. Johnston and D. B. Stewart, Newcastle University College, The University of New South Wales, Tighe’s Hill 2N, Australia IND. ENG. CHEM., PROCESS DESIGN DEVELOP. 3,5-7 (1964)

DECONTAMINATION OF THORIUM. DIRECT PRECIPITATION OF

BUTYL PHOSPHATE

Direct precipitation of thorium sulfate from thorium nitrate solu- tion in 46 vol. yo TBP-Varsol mixtures by means of dilute sulfuric acid allows exceptionally high decontamination of thorium from uranium. Decontamination factors are reported for Cu +2,

Crf3, Mo04-2, K+, Ni+2, Cdf2, C O + ~ , Zn+2, Tii4, Caf2, Na+, Fet3, Zrt4, and Pod-3.

K. J . Bril and P. G. de Sabdia Arazijn, Research Laboratory, Orquima S. A . , S& Paulo, Brazil IND. ENG. CHEM., PROCESS DESIGN DEVELOP. 3,8-10 (1964)

THORIUM SULFATE FROM THORIUM NITRATE SOLUTIONS IN TRI-

PRODUCTION OF URANIUM DIOXIDE BY FLAME DENITRATION

A continuous process has been developed for the direct conversion of uranyl nitrate solution to uranium dioxide. The solution is sprayed direcely into a reducing hydrocarbon-air flame in which dehydration, denitration, and reduction take place. The reactor temperature, normally at least 1800° F. at the exit end, is controlled by the uranyl nitrate flow and by excess hydrocarbon introduced around the spray nozzle. Powder build-up on the wall and residence time are controlled by a Venturi-shaped reaction chamber. Conversions to 8270 UOS have been achieved at production rates of 242 pounds of uranium per hour on a pilot

scale, while percentages as high as 96% have been produced in the laboratory. The product is a finely divided, low-density powder which is equally adaptable to oxide fuel element fabrica- tion or additional chemical processing. Additional work is needed to optimize the processing variables in order to provide conversion to UOz in excess of the 97% (assuming the remainder is U30,) necessary for the production of high-grade uranium metal.

W. H. Hedley, R. J . Roehrs, and W. T. Trask, Jr., Mallinckrodt Chemical Works, Saint Charles, Mo. IND. ENG. CHEM., PROCESS DESIGN DEVELOP. 3,ll-14 (1964)

TERMINAL AND AVERAGING CONTROL OF PYROLYSIS IN A TUBULAR REACTOR

A vapor-phase endothermic chemical reaction may be controlled to satisfy both a desired terminal conversion level and a desired average conversion level. Both control problems may be treated similarly by dynamic programming. The conversion, tempera- ture, and pressure profiles along the tubular reactor are generated. The computational procedure and difficulties are discussed.

Sanford M . Roberts, I B M Federal Systems Division, Houston, Tex. IND. END. CHEM., PROCESS DESIGN DEVELOP. 3,14-18 (1964)

KASCHIG SYNTHESIS OF HYDRAZINE. INVESTIGATION OF THE CHLORAMINE FORMATION REACTION

The chloramine formation stage of the Raschig synthesis of hydra- zine has been studied by reaction of ammonia and sodium hypo- chlorite in a glass apparatus. Two factorial experiments were carried out to study the effect of eight variables. In the first ex- periment the chloramine content of the reaction mixture was estimated by ultraviolet spectrophotometer; in the second, nitrogen evolution was measured in a specially designed gas collector. Ammonia and sodium hypochlorite concentration and mole ratio of NH3 to NaOCl exerted the greatest influence on chloramine yield. These have been further studied over a wide range of concentrations and the results expressed in the form of chloramine yield and concentration contours. In general, chloramine yield increases with decrease in ammonia and hypochlorite concentra- tions and increase in mole ratio ; increased yields are accompanied by decreased chloramine product concentrations,

S. R. M . Ellis, The University of Birmingham, Birmingham, England, G. V. Jeffreys, University of Manchester, Manchester, England, J . T. Wharton, E. I. du Pont de Nemours @ Go., Im., Wilmington, Del. IND. ENG. CHEM., PROCESS DESIGN DEVELOP. 3,18-22 (1964)

OXIDATIVE DEALKYLATION OF ALKYLAROMATIC HYDROCARBONS. SELECTIVE VAPOR-PHASE CATALYTIC OXIDATION OF ALKYLARO- MATIC HYDROCARBONS TO THEIR PARENT HOMOLOGS

Alkylaromatic hydrocarbons may be selectively dealkylated to lower homologs under conditions of controlled vapor-phase catalytic oxidation. Various metal oxides were screened as catalysts. Cadmia proved effective. Effects of temperature, oxygen concentration, and cadmia concentration were studied using a gas-liquid chromatographic microreactor and an experi- mental design. Yields and conversions were correlated with variables by least squares fitting of the data to second-degree polynomials. Best results for the oxidation of l-methylnaphtha- lene to naphthalene were obtained at 400 to 450 O C . over 2 to 8 weight yo cadmia with 5 to 25 weight % oxygen, yielding 30 to 62 i 5 weight yo naphthalene at conversion levels of 20 to 25 =k 3 weight %. Charles J. Norton and Thurle E. Moss, Denver Research Center, Marathon Oil Co., Littleton, Colo. IND. ENC. CHEM., PROCESS DESIGN DEVELOP. 3,23-32 (1964)

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