THE CHEMICAL WORLD THIS WEEK
Revivification of W i t h Superhe
one i-nar Steam Reported
C & E N REPORTS: Second Bone C h a r C o n f e r e n c e
W A S H I N C T O N . 1). ('. — Spent bone char has been succr.vstui y reactivated on an e\periment.il scale 1: y treatment with sup< iliratrd .steam. In the investigation rcported !>> K. C. L. Hosworth ot Colonial Snuar Refining Co. oi Sxdney, Australia, it w.is loiind that superheated steam acts as an effective oxidizing agent capable ol reinoN ing organic impurities. Steam treatment has the effect ol h> cholyzing the calcium sulfide present in the char, which means that this undesirable constituent is progrcssivelx removed. When char is revivified in this maimer, the product compares favorably with that prepared by standard treatment. There is no significant cumulative change in the physical or chemical properties- ot steam-treated char—apart from a slight loss of carbon and a small apparent increase in the char's adsorptive capacity, possibly associated with the selective oxidation of carbonaceous constituents ot low adsorptive power. boswmlh's icpoit was piesenled at the Second Technical Conference on Bone Char, held here at the National Bureau ot Standards, Max- o and 4. More than 20 papers on bone; char research were presented at the conference, which was attended by representatives of sugar refiners in the United States, Cuba, Canada, England. Scotland, Belgium, South Africa, and Australia,
During the two-day meeting, a scroll honoring the 50-year-old National Bureau of Standards tor its scientifie^achievements and "its in\ estimations ind publications in the field of sugar chemistry and technology which have been unique and invaluable contributions to the sugar industry on a world-wide basis," was presented to E. I*. Condon, director ot NBS, bx J. W. Lowe, president of the board of directors, Bone Char Research Project, Inc. Charred animal b o n e is used in enormous quantities in the sugar refining industry for the purification a n d decolorizing of raw sugar. Improvements in the rexixifuation process, the standardization of test procedures, and the development of new filtration processes were among C & E N REPORTS:
Rotary C h a r Kiln E. W i n g and R. S. Patterson of t h e Canada and Dominion Sugar Co. reported on experiments xvhich have been conducted over the past fexv years with a rotary-type kiln xvhich xvas originally a Weinrich decarbonizer. Changes xvere made in the decarbonizer to adapt it to the revivification of char. Experiments on the kiln are still in progress, b u t indications are that rotary revivifying units are practical and economical. C. W . Muller, Jr., of National S u g a r Refining Co. presented a report on t h e use of recording and controlling p y r o m eters in connection xvith char kilns. T h e double char filtration of high-purity liquors was discussed by E. D. Gillette of Refined Syrups & Sugars, Inc., while t h e continuous counter-current "sweeteningofi" and "washing" of bone char w e r e described by G. C. Conrad and Leon Codchaux of Godchaux Sugars, Inc.
Symposium on F i l t r a t i o n , N e w J e r s e y Section A l C h E
Filtration A p p r o a c h i n g Status of Exact Science Filter selection on theoretical basis will soon be possible, speaker feels NEWARK.—Filtration, of all the unit operations xvith the exception or heat transfer, is most rapidly approaching the status or an exact science and should soon reach a point at xvhich it xvill be possible to prescribe filter design, media, and cycles for a specificfiltration problem purely from theoretical considerations. Thus spoke S. A. Miller of the University ot Kansas here at the second annual all-day meeting of the New Jersey Section of the American Institute of Chemical Engineers. Miller opened the meeting xvith a review of recent advances in filtration theory.
Representing the British refining industry, Geoffrey Fairrie of T a t e & Lyle, Ltd., Liverpool, E n g l a n d , addresses dinner meeting at Shoreham H o t e l • during bone char conference. Listening are J. W . Loxve, president of Bone C h a r Research Project, Inc., and Mrs. Loxve
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the main topics covered at the recent conference.
CHEMICAL
I Ic defined filtration as a p h e n o m e n o n ot unsteady-state fluid dynamics in w h i c h the resistance is x'ariable and the fioxv rate need not be constant. T h e flow pattern is complex and the t e m p e r a t u r e gradient is influenced by a large n u m b e r of factors. Because of these complex conditions a successful general and rigorous description of filtration still d o r s not exist but Miller pointed out some ot the major advances which have resulted from the concentration of effort xvhich has been applied to this operation in the last 10 years. This period has seen t h e d e v e l o p ment of the direct relationship b e t w e e n the pressure on the filter cake a n d its resistance to the passage of t h e filtrate. The mechanism of filtration has been divided into the trapping of single particles in a capillary orifice a n d the absorption oJt particles on the capillary walls. T h e s e two> mechanisms stand at opposite ends, of ai filtration spectrum and all cases of filtration can be located betxveen t h e txvo. Another approach has been m a d e from the study of frictional losses in filter cakes. Some theses for these studies have b e e n borrowed from studies of granular beds*. Although the results have been only a p proximate they do give an estimation ofc the amount of air required for the b l o w ing of the cake and t h e moisture content; ol the cake after blowing.
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ENGINEERING
NEWS
