Industrial and Engineering Chemistry : industrial edition, Vol. 37, No. 10

Industrial and

Engineering Chemistry

Volume 37 • Number 10 OCTOBER, 1945

R E P R IN T E D IT IO N

A D V E R T ISIN G O M IT T E D

E D IT O R : W ALTER J. M U R P H Y Assistant to Editor: N . A . PARKINSON M anaging Editor: F. J . V A N A N T W E R P E N

Associate Editor: J A M E S M . C R O W E

M idwest Editor: Ro b e r t F . Go u l d

Industrial Editor: H A R R Y W . S TE N ER SO N

Manuscript Editor: H E L E N K . N E W T O N

M ake-up Editor: B E R T H A R E Y N O LD S

Manuscript Assistant: S T E LL A A N D E R S O N

Contributing Editors Ch a r l e s Ow e n Br o w n

Ra l p h H . Mu n c h Ha r o l d R. Mu r d o c k Wa l t e r v o n Pe c h m a n n

Advisory Board

W . L B AD GER H . E B A R N A R D W . H . D O W G A S T O N D U B O IS G U S T A V U S J . ESSELEN PER 1C F R O L IC H C F. KETTERING O . L M A Y C S. M IN E R

H . R. M U R D O C K C . F. P R U TTO N A . S. R IC H A R D S O N W . A . S C H M ID T R. N . SHREVE L V . STECK C M . A . STINE E. C S U L L IV A N E. R. W E ID L E IN J . M . WEISS

The A m e ric a n C h em ical S o c ie ty assumes no re­

s p o n s ib ility f o r th e statements and o p in io n s ad­

vanced b y c o n trib u to rs to Its p u b lic a tio n s . C o p y r ig h t 1 9 4 5 b y A m e rica n Chem ical S ocie ty

3 2 ,2 0 0 co p ie s o f this Issue p rin te d

Fuel savings « * n i d e in th* plant of Texas Gulf Sulphur Company (s»a photograph above) b y passing Incoming water through economizers which extract h u t from the watte flue gases.

ISSUED OCTOBER 16, 1945 • VOL. 37, NO. 10 • CONSECUTIVE NO. 19 DEPARTMENTS

E d ito ria ls ... 911

H e a d lin e s ...1027

I. & E. C. Reports ... *5

A s W e See It . . . . ... *87

Equipment and Design. Charles O w e n B r o w n ... *99

Instrumentation. Ralph H . Munch ... *105

Waste Utilization. Harold R. M u r d o c k... *111

Plant Management. W alter von Pechmann... *117

Last-Minute Flashes... *164

TECHNICAL ARTICLES Application of Automatic Controllers to H eat Exchangers... J. L. M ore, F. J. Q u a il, and J. W . Bain 912 Corrosion of Lead by Oxidizing A gents and Laurie A cid in Hydrocarbon Solvents C. F. Prutton, David Turnbull, and D. R. Frey 917 Alkylation of Isoparaffins by Olefins in Presence of Hydrogen Fluoride . . . . Carl B. Linn and A ristid V. Grosse 924 Vapor-Liquid Equilibria for Natural Gas-Crude O il Mixtures. C. H . Roland . . 930

TNT Wastes from Shell-Loading P la n ts ... C. C. Rucnhoft, M . LeBosquet, Jr., and W illiam G . M eckler 937 Carboxymethylcellulose. Uses and A p p lic a tio n s ... C. B. Hollabaugh, Leland H. Burt, and Anna Peterson Walsh 943 Physical Testing of G lue Compositions. . . . . W . C. Griffin and E. G . Almy 948 Tall O il Esters as Plasticizers for GR-S. W . I. Harber and C. S’ Y o r a n... 953

Two-Component Equilibrium Curves for Multicomponent Fractionation... Frank J. Jenny and Michael J. Cicalese 956 Cellulose Compounds in Thermoplastic L a m i n a t e s ... C. W. Eurenius, R. H . Hecht, W illiam Koch, and H . C. Malpass 959 A conitic A cid from Citric A cid by Catalytic Dehydration ... Robert R. Umbdenstock and Paul F. Bruins 963 Estérification of Butanol and A cetic A cid. C. E. Leyes and D. F. Othmer . . . 968

Viscosity of Carbonated Aluminate Solutions. J. M . H a ll and S. J. Green . . 977

Peanut Protein Hydrates. R. S. Burnett, E. D. Parker, and E. J. Roberts . . . . 9 80 Catalytic Cracking of Pure Hydrocarbons. B. S. Greensfelder and H . H. Voge . 983 Redwood Products as Inhibitors of Oxidation in Petroleum Hydrocarbons. . . . H . F. Lewis, M . A . Buchanan, D. Fronmuller, and E. F. Kurth 988 Nomographs for Enthalpies of Pure Hydrocarbons and Their M ix tu re s ... Edward G . Scheibel and Frank J. Jenny 990 Production of Tyrothricin in Cultures of Bacillus b r e v i s ... J. C. Lewis, Keene P. Dimick, and I. C. Feustel 996 Factors Affecting Boiling in a Liquid. Reinhold F. Larson . ... 1004

Occurrence of Metastable States of Liquid and Vapor. Reinhold F. Larson . . 1010 Specific Gravity of Aluminum Sulfate Solutions. J. W . Silva and J. E. Chenevey 1016 Vapor Pressure of Water A dsorbed on Dehydrated Eggs. Benjamin M akow er . 1018 Solvent Extraction of Cottonseed and Peanut O i l s ...

E. F. Pollard, H . L. E. V ix, and E. A . Gastrock 1022

* Indicates page number In (he advertising section.

Published b y the A m e rica n Chem ical S o ciety at Easton, Pa. E d ito ria l H e a d ­ quarters: 1 1 5 5 1 6th S tree t, N . W . , W ashington 6 , D. C ./ te le p h o n e , R e pu b lic 5 3 0 1 , c a b le , Jiechem (W ash in gto n). N e w Y o rk E dito ria l B ranch, 6 0 East 4 2 n d S treet, N e w Y o rk 1 7 , N . Y .; te lep ho n e, M u rra y H il l 2 -4 6 6 2 . C h ica go E d ito ria l B ranch, 3 1 0 South M ic h ig a n A v e n u e , C h ica go 4 , 111., te le p h o n e , W abash 7 3 7 6 . Business O ffic e : A m e rica n Chem ical S ociety, 1 1 5 5 1 6th S treet, N . W . . W ashington 6 , D. C . A d v e rtis in g O ffic e : 3 3 2 W est 4 2 n d S treet, N e w Y o rk 1 8 , N . V ., tele p h o n e , Bryant 9 -4 4 3 0 .

Entered as second-class matter at the Post O ffic e at Easton, Pa., u nd er the A c t o f M a rc h 3 , 1 8 7 9 , as 2 4 times a year— Industrial E dition m onthly on the 1st, A n a ly tic a l E d itio n m onthly o n the 15th. A c c e p ta n c e f o r m ailing at special rate o f postage p r o ­ v id e d f o r in Section 1103, A c t o f O c to b e r 3 ,1 9 1 7 , auth orized J u ly 1 3 ,1 9 1 8 .

Remittances and o rd e rs fo r subscriptions and f o r single c o p ie s , notices o f changes o f address and n e w professional co n n e c tio n s , and claims f o r missing numbers should be sent to th e A m e rica n Chem ical S o c ie ty , 1 1 5 5 1 6th S tree t, N . w . , W ashington 6 ,

D. C . Changes o f address fo r the industrial E d ition must be received on o r b e fo re the 1 8th o f the p re c e d in g month and fo r the A n a ly tic a l E dition n ot la ter than the 3 0th o f the p re c e d in g month. Claims f o r missing numbers w i l l n o t be a llo w e d ( 1 ) i f re­

ceived more than 6 0 days from date o f issue ( o w in g to the hazards o f w artim e d e liv e ry , no claims can be h on ored from subscribers outside o f N o rth A m e ric a ), ( 2 ) i f loss was due to fa ilu re o f n o tic e o f change o f address to be rece ived b e fo re the dates specified in the p re c e d in g sentence, o r ( 3 ) if the reason f o r claim is "missing from file s ".

A n n u a l subscriptions— Industrial E d itio n and A n a ly tic a l E d ition so ld o n ly as a u n it, members $ 3 .0 0 , nonmembers $ 4 .0 0 . Postage to countries n o t in the Pan-A m eri­

can U n io n $ 2 .2 5 , Canadian postage $ 0 .7 5 . S ingle copies— c u rre n t Issues, In­

d ustrial E dition $ 0 .7 5 , A n a ly tic a l E d ition $ 0 .5 0 , back numbers, Industrial E d ition

$ 0 .8 0 , A n a ly tic a l E dition prices on request, special rates to members.

The A m erican Chem ical S ociety also publishes Ch em ic a l a n d E ngin eerin g News, Chemical Abs tracts , and J o u r n a l o f the A m eric an Ch em ic a l Society. Rates on re ­ quest.

INDUSTRIAL ^{a n d} ENGINEERING CHEMISTRY

REPORTS

ON THE CHEMICAL W OILP TODAY

m iu u d x M jy

A to m I te m s . N o s o o n e r h a d th e a to m b o m b e x p lo sio n b e co m e n e w s t h a n p h o n e s b e g a n to r in g in t h e office of L ie u te n a n t C o lo n el C . C o n so d in e , C o rp s of E n g in e e rs in W a s h in g to n . F o r five d a y s a n d n ig h ts th e C o lo n el a n d h is s ta ff c o n tin u o u s ly r e m a in e d o n d u t y a n s w e rin g q u e s­

tio n s , c le a rin g sto rie s , a n d a rra n g in g in te rv ie w s a b o u t th e e v e n t. S le ep in g o n th e floor to a n s w e r in q u irie s c o m in g in a t a n y h o u r d o e s n o t im p ro v e o n e ’s d is p o s itio n , b u t so m e o f th e in c id e n ts p ro v id e d la u g h s w h ic h h e lp e d p u t th e d e v e lo p m e n t in a d iffe re n t lig h t. P h o n e calls a v e ra g e d fo u r h u n d r e d a n d fifty a d a y , a n d tw o e x tr a p h o n e s, in a d d itio n to th e m a n y a lr e a d y in th e office, h a d to b e in ­ sta lle d . T h e U n ite d S ta te s re a c te d a s o n ly she could.

F ir s t a ra d io s ta tio n re q u es te d th e W a r D e p a rtm e n t to re p e a t th e explosion so t h a t th e so u n d m ig h t b e p ick ed u p b y s tra te g ic a lly p laced m icro p h o n es. A le tte r w as receiv ed from a n ex-sailor w ho w a n te d to b e d ro p p e d w ith a n a to m ic b o m b a n d ra d io e q u ip m e n t in o rd e r to give a p la y -b y -p la y d escrip ­ tio n of w h a t h ap p en e d .

A n o th e r ta s k of C o n so d in e’s w as clearing c red its. A fer­

tilizer co m p a n y w hich h a d p u t m a te ria l o n th e law n of one h o sp ita l of th e p la n t in T en n essee w a n ted to te ll th e p u b lic of its im p o rta n t p a r t in m ak in g th e a to m b o m b . A n o th e r fertilizer co m p an y w a n ted clearan ce on a n a d v e rtise m e n t w hich p ro claim ed th a t, of th e th o u sa n d -o d d in d u s tria l com ­ p a n ie s in u p p e r N ew Y o rk s ta te w hich a ssisted in m ak in g th e b om b, th e y alone h a d n o th in g to do w ith it. A le tte r of con­

g ra tu la tio n a rriv e d w hich, in a d d itio n , p o in te d o u t tw o fu rth e r goals to b e reach ed b y th e a to m b o m b g ro u p — over­

com ing g ra v ity so t h a t a irp la n es could n o t fall, a n d m ak in g com m ercial th e cold lig h t of th e firefly.

T h e n ew sp ap ers re p o rte d on th e fa rm e r w ho w a n ted to p u rc h as e som e a to m b o m b s to disco u rag e in se cts fro m b o th e r­

ing h is crops, b u t th e y m issed th e p ro sp e c to r w ho claim ed to h a v e discovered a lode of v a lu a b le h ig h -g rad e ore 25 fe et b e­

low th e su rface of som e ro ck . W o u ld th e W ar D e p a rtm e n t p lease oblige b y d ro p p in g a b o m b to s trip off th e o v erb u rd en ?

D u rin g th e re c e n t h u rrica n e th e m a y o r of a F lo rid a c ity w a n ted a b o m b d ro p p e d in th e m id d le of th e s to rm to tu r n it a w a y fro m his m etro p o lis. W h ile on th e s u b je c t of w eath er, th e re w as th e m o th e r w ho h a d h e a rd t h a t th e c lim ate w ould b e affected b y all th ese a to m s ; w ould C o n so d in e’s office

p lease te ll h e r w h e th er i t w ould b eco m e colder, in o rd e r to give h e r a chance to m ak e s u ita b le clo th in g fo r h e r ch ild ren ?

W h ile we w ere in te rv iew in g th e C olonel, a S e n a to r called to a s k how h e could o b ta in p erm issio n for a c o n s titu e n t to v is it th e site of th e b o m b explosion in N ew M ex ico ; th e con­

s titu e n t, a d o c to r, w a n ted to cam p th e re w ith h is w ife an d c h ild ren fo r a tw o-w eek v a c a tio n .

C oncessionaires b e g an b e a tin g th e to m -to m . C o u ld th e y o b ta in th e concession to th e a to m ic b o m b c r a te r in N ew M exico so t h a t jew elery m ig h t b e m a d e of th e s to n e w hich fused in to green, h a rd p ellets w h en th e b o m b ex ploded?

T h e y ev en h a d a n a m e for it — “ a to m ic ja d e ” .

O v e rn ig h t th e office of C olonel C o n so d in e c h an g e d fro m a secrecy o rg an izatio n , b e n t on k e ep in g a to m s o u t of p u b lic in fo rm a tio n channels, in to a p u b lic ity office, h a n d lin g th e b ig g est s to ry ev er e n c o u n te re d a n d try in g to k eep sp ecu la­

tio n , en th u sia sm , a n d “ g u e sstim a tio n s” w ith in re as o n . O ne of th e officers of th e D e p a rtm e n t w as in S w itz erla n d w h en th e b o m b w as d ro p p e d . N o t b ein g ab le to re a d th e lan g u a g e b u t seeing u n m is ta k a b le h ead lin es a b o u t th e e v e n t, h e could o n ly guess t h a t th e w eap o n h a d b e e n u sed . W ith o u t th e d e ta ils h e d a re d n o t q u e stio n n a tiv e s fo r fe ar i t w as n o t w h a t h e th o u g h t a n d his in te re s t m ig h t p ro v id e a n unw elcom e leak .

A new sh o u ld er in sig n ia h a s b e en d esig n ed for th o se w ho w orked on th e p ro je c t. In sid e th e to p h a lf of th e shield, w hich h as a b lu e b a ck g ro u n d , is a n A rm y serv ice s ta r A ro u n d th e s ta r is th e loop of a q u e stio n m a rk , th e ta il cross­

ing th e b lu e field in th e form of a zigzag of lig h tn in g w hich tra v e ls to th e b o tto m of th e p a tc h w h ere i t strik e s a ro u n d golf b a ll (p re su m ab ly a n a to m ) a n d b re a k s i t in to th re e p a rts . T h is h a s becom e a co llecto r’s ite m , a n d a t th e tim e we w ere in th e office, a le tte r cam e fro m a “ fo u r-s ta r g e n e ra l” , aged eleven, a n d a d o p te d son of th e R a in b o w D iv isio n ; h e, w ith h is

“ d a d d y ” w as ru n n in g a ra ce w ith th e U .S .O . h o ste ss in h is to w n as to w ho w ould h a v e th e p a tc h first. W o u ld G en eral G roves please oblige, etc.?

T h en , too, th e re w as th e p e rso n w ho closed h is le tte r w ith

“Y o u rs for th e c o n q u est of sp a c e ” ; a s y o u c an guess, i t h a d to do w ith ro c k e tin g to th e m oon. C o u ld h e g e t th e first p e rm it to u se a to m ic po w er for th is p u rp o se? C o n so d in e an sw ered th is q u e stio n easily b y re fe rrin g th e w rite r to th e I n te r s ta te C o m m erce C om m ission. (Continued on page 8 )

/J n in U *f**ta U u e . n to tU ltb f cUtf&U fa * c U e m iiU , c U e m ia a l e *u fin eefu i, a n d in th e. c h e m ic a l p H o d u cin y and. o U am io al co *U u m i*u f i nduAbumA.

« S & & & *•*«•**• " ¿ a " a s a * - 4- 4«.

Today Today

Lactic Acid Secret. T h e u se of la c tic a c id in n o rm a l tim e s fo r th e m a n u f a c tu r e of su c h e sse n tia ls a s le a th e r, te x tile s , foods, a n d liq u o rs d o es n o t e x p la in th e larg e in ­ crease in la c tic p ro d u c tio n w h ich to o k p lac e d u rin g th e w a r. T h e c u r ta in on th is m y s te ry h a s n o w b e en p a r tia lly lifte d b y m ilita r y a u th o r itie s , a n d we fin d t h a t la c tic p e r­

fo rm e d one of th e w a r’s sm a ll b u t im p o r ta n t jo b s. I t w as u se d in a fire-q u e n c h in g s o lu tio n to p r e v e n t ex p lo sio n an d d e a th in t a n k in te rio rs .

M a n y tra g e d ie s h a d ta k e n p lac e in sid e of ta n k s w hen e n em y sh ells p ie rc e d th e a rm o r a n d s e t fire to a m m u n itio n su p p lies. A n u m b e r of re m e d ies h a d b e en tr ie d u n su c c ess­

fu lly u n til so m eo n e th o u g h t of th e h ig h su rfa c e a c tiv ity a n d w e ttin g p ro p e rtie s of a s o lu tio n of a la c tic a c id com ­ p o u n d . I n a c tu a l p ra c tic e , th e s o lu tio n , A m m u d a m p , w as ja c k e te d a ro u n d th e t a n k ’s m ag a z in e , sides, a n d b o tto m , as w ell as in th e sp a c es b e tw e e n th e sh e ll ra c k s . A n in v a d ­ in g sh ell re le a s e d th e fire-q u e n c h in g m ed iu m , a n d e v e n if th e a m m u n itio n w as s e t a b la z e, th e re s u ltin g fire co u ld be q u ic k ly b r o u g h t u n d e r c o n tro l.

I n th is m a n n e r a p r o d u c t n o rm a lly u se d in th e p r e p a r a ­ tio n of s a u e r k ra u t, p ick les, a n d essen ces m a d e o n e of c h e m is try ’s v a lu a b le c o n trib u tio n s to w a rfa re . T h e first sh ip m en t of th is fire-eater w as m ad e on O cto b er 30,1944, th ree m o n th s a fte r th e m a n u fa ctu re rs h a d b een ask ed b y A rm y O rdnance to w ork w ith th e G o v e rn m en t on th e problem .

Swords and Plowshares. T h e sm oke g e n era to rs w hich so effectively concealed U . S. tro o p m o v em en ts m a y find a good p o stw a r m a rk e t. T h e S ta n d a rd Oil C o m p an y of N ew Jersey is co n d u ctin g exp erim en ts o n th e use of th is g e n era to r in th e citru s a rea . A t p re se n t sm oke p o ts a re n o t efficient in p re ­ v e n tin g fro st losses, b u t th e sm oke g e n era to r can crea te a dense b la n k e t of sm oke w hich m ig h t m ore fully p ro te c t th e trees. T h is m ach in e m ig h t also be used to disperse insecticides as a fine m is t over larg e areas of o rch ard s.

Absorbable Sponge. I n I . & E . C . R e p o r ts fo r M a y , 1945 (p a g e 5), w e s p o k e of a b s o rb a b le cellu lo se. A n o th e r p h y sio lo g ic a lly a b s o rb a b le p r o d u c t h a s n o w m a d e its a p ­ p e a ra n c e , w ith th e h e lp of th e U p jo h n C o m p a n y . I t w as re p o r te d b y J o h n T . C o rre ll, H a z e l R . P re n tic e , a n d E . C . W ise on th e p ro g ra m of th e D iv isio n of M e d icin a l C h e m is try of th e Am e r ic a n Ch e m i c a l So c i e t y’s 1945 M e e tin g -in -P rin t. T h e n ew p r o d u c t, G e lfo am , is a sp o n g e of p a r tia lly d e n a tu r e d p r o te in m a te ria l. A lth o u g h i t was d e v e lo p e d sp e c ific ally as a m e d iu m fo r th ro m b in , th e b lo o d -c lo ttin g e n zy m e , i t w ill p r o b a b ly h a v e g e n e ra l a p ­ p lic a tio n in s u rg e ry w h e re a sp o n g e t h a t c a n b e le f t in th e b o d y w ill b e u se fu l.

T h e effectiveness of th ro m b in w as lim ited b y th e fa c t th a t i t w as a p p lie d as a fluid. A sponge t h a t co u ld b e so ak ed in th ro m b in , squeezed o u t, a n d p laced on th e h em o rrh ag e to a b so rb b lo o d a n d h o ld th e c lo t w ould fa c ilita te its use.

Sponges

w ere trie d , b u t th e g elatin sponge a p p ea red to b e th e m o st sa tis fa c to ry in re g ard to b o th p h y sical p ro p erties a n d ab so rp ­ tio n . T h e g e la tin sponge is p re p are d b y a ir-d ry in g a foam m ad e from a specially p re p are d g elatin so lution, a n d is lig h t, to u g h , nonelastic, a n d porous. A fte r th e sponge h as d ried , it is p ack ag ed a n d sterilized b y d ry h e a t since a u to c lav in g re ­ su lts in a com plete loss of desired p ro p e rtie s. I t is n o t re ad ily w et b y w a te r u n til it is k n ead e d to b re a k th e a ir cells, w here­

u p o n i t will im b ib e u p to fifty tim es its w eig h t a n d c an b e used re p ea te d ly . I t is n o t soluble in w ater, b u t a 1% so lu tio n of U .S .P . X I I p ep sin will d ig est a 100-mg. sponge in vitro in a b o u t 30 m in u tes a t 37° C. E x te n siv e clinical in v estig a tio n s on la b o ra to ry an im als h av e d e m o n s tra te d t h a t i t is ab so rb ed in th e b o d y a n d t h a t i t d isap p ears, -w ith no a n tig e n ic m a n i­

festatio n s, in 30 to 90 d ays.

Plastics b y the M ile. T h e w o rld w as a s to u n d e d w h en th e la te T h o m a s A . E d is o n su c c ee d ed in se n d in g fo u r M o rse te le g ra p h ic tra n s m is s io n s o v e r one lin e w ith o u t in te r f e r ­ ence. T o d a y , th a n k s to c o n tin u e d sc ien tific d e v e lo p m e n t of c o m m u n ic a tio n s e q u ip m e n t, i t is p o ssib le t o u se a sin g le lin e fo r a s m a n y a s 1440 tw o -w a y c o n v e rs a tio n s . T h e co ax ial c ab le is re sp o n sib le a n d its su ccess is a s c rib e d to its h ig h in s u la tio n p ro p e rtie s . T h e in s u la tin g re sin is p o ly ­ e th y le n e , a s tr a ig h t- c h a in th e r m o p la s tic p o ly m e r of liq u id e th y le n e . I t s low e le c tric a l losses a n d c h em ica l a n d p h y s i­

cal p ro p e rtie s a re id e a l fo r th is p u rp o se .

As w ith m a n y o th e r re c e n t d isco v eries, p o ly e th y le n e d e m o n s tr a te d its v a lu e on a la rg e scale in m ilita r y e q u ip ­ m e n t. A lth o u g h m a n u f a c tu r e d in B r ita in o n a m o d e s t scale, i t is s a id t h a t th e I . G . F a r b e n in d u s tr ie o b ta in e d th e p la s tic fo r u se in u n d e rs e a cab les. W h e n th e w a r b e g a n in S e p te m b e r, 1939, th e B r itis h e x p a n d e d p o ly e th y le n e p ro d u c tio n fo r in s u la tio n in r a d a r a s w ell a s in c ab le s. I n th is c o u n tr y o u tp u t of th e re sin w as u n d e r ta k e n b y tw o le a d in g c h em ica l m a n u fa c tu re rs fo r s u c h m ilita ry a p p lic a ­ tio n s as ra d a r a n d sh ip b o a rd com m unications.

P ro d u c tiv e c a p a c ity c r e a te d d u rin g th e w a r fo r p o ly ­ e th y le n e is n o w a v a ila b le fo r m a n y u se s b esid es co ax ia l cab les, a lth o u g h t h a t field a p p e a rs to b e th e m o s t p ro m is ­ in g . C a b le s of th is s o r t a re n e c e s s a ry fo r lin k in g to g e th e r te le v is io n s ta tio n s , a n d th e f u tu r e m a y w itn e s s a w id e use of p o ly e th y le n e fo r th is a p p lic a tio n a lo n e . A s in s u la tio n fo r u ltr a h ig h fre q u e n c ie s i t w ill p la y a n im p o r ta n t p a r t in lin k in g to g e th e r a n a tio n w id e te le v is io n n e tw o rk . A s s h u n t lo sses a re b u t o n e tw e lf th of th o s e e x p e rie n c e d w ith h a r d r u b b e r, th e te le p h o n e , also, is e x p e c te d to m a k e e x te n ­ siv e u se of th is m a te ria l.

Our Error. P lu to n iu m c h a n g e s to U -235 th r o u g h em is­

sion of a n a lp h a p a rtic le . L a s t m o n th we b k m e d th is tra n s ­ fo rm atio n o n th e n e u tro n in o u r re p o rt “ A tom ic A ge” . Y ou will be glad to lea rn t h a t th e n e u tro n does n o t h av e to w o rry a b o u t d e g rad in g p lu to n iu m a n d can d e v o te all of its energies to sp littin g ato m s. (Continued on page 12)

I. & E. C.

Report on the .

Chemical World ¿' ca'* ° " wc4 Today

I. & E. C.

Reports on the Chemical World

Today

G o m m e te e

a t t d

O tu lu & b u f

Fertilizer Goes W est. F if te e n y e a r s ag o th e w e s te rn s t a te s a c c o u n te d fo r a v e r y s m a ll p a r t of a n n u a l U n ite d S t a te s fe rtiliz e r c o n s u m p tio n . S in ce 1930 t h e u se of fe r­

tiliz e r s in th e W e s t a n d M id w e st h a s ex p an d ed considerably.

T h e to n n a g e in creases in fe rtiliz e r c o n su m p tio n since 1930, b y area s, a re sh o w n in th e follow ing co m p ilatio n p re p a re d by th e N a tio n a l F e rtiliz e r A sso ciatio n :

% of U. S. C o n s u m p tio n % Increase

1930 1944 in T o n n a g e

N o r th A tla n tic 14 .3 1 3 .9 33

E a s t N o r th C e n tra l 9 . 9 1 4 .8 105

W e s t N o r th C e n tr a l . 1 .3 2 . 7 172

S o u th A tla n tic 5 0 .2 4 3 .3 18

S o u th C e n tr a l 2 2 .0 1 9 .9 23

W e stern 2 . 3 5 .4 222

U n ite d S ta te s 1 0 0 .0 1 0 0 .0 37

T h u s, th e u se of fe rtiliz e r h a s g ain ed m o st ra p id ly in th e W est, E a s t N o r th C e n tra l, a n d W e s t N o r th C e n tra l areas. N a tio n a l fe rtiliz e r co n su m p tio n to ta le d 8,222,000 to n s in 1930 and 12,072,000 to n s in 1944.

T h e fa c t w hich p a r tly ex p lain s th is new tre n d is t h a t corn h a s re p la ce d c o tto n as th e p rin cip a l fertilized crop. One fa c to r in th is re v ersa l is th e w ide a d o p tio n in th e M id w e st of h y b rid co rn w hich is b ein g given generous to n n ag e s of p la n t food.

F ig u re s for ta g sales d u rin g th e p re w ar y e a r 1939-40, com ­ p a re d w ith sim ilar d a ta for th e fiscal y e a r 1944-45, show th a t fe rtiliz e r sales in th e M id w e st rose fro m 561,000 to 1,208,700 to n s. V ery strik in g in creases h a v e ta k e n p lace also in th e use of fe rtiliz e r fo r fru its , v eg etab les, a n d g rasslan d s. P a stu re s in sev eral w estern sectio n s are still in n eed of fertilizer.

A r e p o rt fro m Io w a sa y s t h a t m a n y so-called fe rtile soils in th e W e s t m a y n o t c o n ta in en o u g h a v ailab le p h o sp h o ru s to p ro d u c e m ax im u m cro p yield s o r good feed. A n o th e r from th e U n iv e rs ity of Illin o is show s t h a t each to n of alfalfa h a y re p re se n ts a n e t rem o v al fro m th e soil of 18 p o u n d s of n itro ­ gen, 3.6 of p h o sp h o ru s, 2.5 of p o tassiu m , a n d a b o u t 125 p o u n d s of lim esto n e. T h e sam e re p o rt co n ten d s t h a t th ese elem en ts m ig h t b e re p la ce d a t a co st of a b o u t fo u r dollars.

I t is n o t su rp risin g , th e n , t h a t o u r fertilizer m an u fa ctu rin g in d u s tr y 'is “ going W e s t” to su p p le m e n t insufficient soil ele­

m e n ts in th o se s ta te s . P ro b a b ly for th e first tim e in h isto ry , a m a n u fa c tu rin g p la n t fo r fertilizers is b ein g e rec te d in Io w a to se rv e th e Io w a a n d M in n e so ta sectio n s. I t is u n d e r con­

s tru c tio n b y th e I n te r n a tio n a l M in e rals & C hem ical C o rp o ra ­ tio n a t M a so n C ity , a n d sh o u ld b e in o p e ratio n in 1946.

F e rtiliz e rs, esp ecially p h o sp h a tes, a re likew ise needed on th e W e s t C o a st. T o m e e t th is new d e m a n d a n o th e r m a n u ­ fa c tu re r, th e S ta u ffer C h em ical C o m p an y , is e n te rin g in to a d d itio n a l lo n g -te rm c o n tra c ts for p h o sp h a te ro ck w hich will d o u b le its p ro d u c tio n of s u p e rp h o sp h a te in 1946. I n th is m a n n e r th e fe rtiliz e r in d u s try is co rrectin g a su p p ly s itu a tio n w h ich h as b e e n cau sed in th e p a s t b y d istrib u tio n in ad e ­ q u acies r a th e r th a n b y la c k of sufficient c ap a c ity . T ra n s ­ p o r ta tio n a n d its co sts h a v e b e en m o re of a p ro b lem to ag ri­

c u ltu re in th e W e s t t h a n to fa rm e rs in th e A tla n tic a n d s o u th ­

e rn s ta te s . (Continued on page 14)

12

Laboratory Rubber Goods. S oon a fte r th e s t a r t of th e w ar, th e c o m p o sitio n of la b o ra to ry ru b b e r goods w as c u t fro m 98 to 4 2 % p u re g u m , w ith g o o d -g rad e re claim m ak in g u p th e d ifference; b u t i t w as n o t long before n a tu r a l w as e lim in a ted a lto g e th e r e x cep t in p ro d u c ts fox su rg ical u se. F o r tu b in g , th e first s y n th e tic w as n e o p ren e w h ich h a d com e in to use b efore th e w a r; la te r G R -S w as a d d e d , th e n th e B u n a N ’s, an d finally B u ty l ru b b e r. S p ecial-p u rp o se s y n th e tic s a re a c tu a lly im p ro v e m en ts o v e r n a tu r a l ru b b e r. G R -S , th e g en eral- p u rp o se ru b b e r, h o w ev er, is s tr ic tly a s u b s titu te t h a t is tid in g u s o v er a c ritica l p e rio d . T h e u se of n eo p ren e a n d B u ty l in p a rtic u la r, a n d p ro b a b ly of th e B u n a N ’s, w ill c o n tin u e re g a rd ­ less of th e p rice of n a tu r a l ru b b e r. N eo p ren e is u se d w h ere its oil- a n d o zo n e-re sistan t a n d n o n c rac k in g p ro p e rtie s a re de­

sired. I t can also b e m a d e so t h a t i t will n o t s u p p o rt com ­ b u stio n . T h e B u n a N ’s a re c h ara c te riz e d b y e x tre m ely low sw elling in oils. B u ty l is in e r t to m o s t chem icals, a n d its im p e rm ea b ility to a ir, w hich is fo u r tim es t h a t of n a tu r a l ru b ­ b er, recom m ends i t esp ecially for v a c u u m tu b in g . M o s t h a n d -w rap p e d tu b in g now b ein g m a d e is B u ty l.

A ll ru b b e r tu b in g is e x tru d e d , b u t a b e tte r p ro d u c t is ob ­ ta in e d if i t is h a n d -w rap p e d w ith c lo th o n a m a n d re l fo r cu r­

ing. T h is acc o u n ts fo r th e fa b ric p a tte r n o n m o s t ty p e s of p rew ar tu b in g . Sw elling is p re v e n te d a n d a d e n se r tu b in g is o b tain e d , b u t th e d e m a n d fo r h a n d -w ra p p e d tu b in g fo r a ir­

c ra ft use h a d c re a te d a m an p o w er s h o rta g e in th is ite m . E x ­ tru d e d tu b in g is sim p ly d u s te d w ith ta lc b efo re c u rin g so i t can b e tu rn e d o u t w ith less lab o r. G R -S is b e in g u se d for m o st e x tru d e d tu b in g .

Soybeans and the Future. T h e th ree fo ld in crease in soy­

b e an p ro d u c tio n , fro m 62 m illion b u sh els in 1938-39 to n e arly 200 m illion for e v e ry season since 1942, solved tw o p roblem s.

I t p ro v id ed edible oils fo r in creased w a rtim e n e ed s a n d to fill th e g a p c rea te d b y loss of im p o rte d oils, a n d i t c o n trib u te d to alle v ia tin g sh o rta g es in sto c k feeds. I n d u s tr ia l uses of soy­

b e an p ro d u c ts h a v e n o t p lay e d a sig n ifican t p a r t in th is ex­

pan sio n , n o r h a v e th e y e v er serio u sly affected th e size of the crop.

A s a re s u lt of w a rtim e p ressu res a n d g o v e rn m e n t subsidies, th e so y b ean cro p h a s b e en fo rced b e y o n d its n o rm al level.

So y b ean is k n o w n to b e a n ero d in g cro p o n ro llin g g ro u n d , a n d m a n y p ro d u cers a re grow ing i t o n la n d w h ich c a n n o t su p ­ p o r t it. M a n y fa rm e rs h a v e d isc ard e d th e ir cro p ro ta tio n pro g ram s to m e e t g o v e rn m e n t re q u e s ts fo r o il-p ro d u cin g crops. A lth o u g h h ig h p rices a id e d in stim u la tin g th e s e in­

creases, th e p a trio tic a p p e a l to serv e th e w a r effo rt b y grow ing so y b ean s affected m a n y farm ers a n d c o n trib u te d to in creases in a w ay t h a t prices alo n e could n e v er h a v e d o n e. T h erefo re, declines m ay b e ex p ec ted fro m b o th th es e so u rces.

A lth o u g h i t d id n o t figure larg e ly in to ta l p ro d u c tio n , soy­

b e an flour c a p a c ity w as ex p an d e d som e th ir t y fold d u rin g th e w ar to 1.5 b illio n p o u n d s in 1943. U ltim a te p ro d u c tio n , how ever, n e v e r exceeded 400 m illion p o u n d s, b ecau se n e ith e r L en d -L ease sh ip m en ts, n eed s fo r re h a b ilita tio n feed in g of o ccupied c o u n tries, n o r d o m estic c o n su m p tio n to a lle v ia te a n tic ip a te d p ro te in sh o rta g e s (Continued on page 22)

14

I. & E. C. Com m ence Report on the

Chemical World Today

assum ed expected p ro p o rtio n s. P o stw ar volum e will p ro b ab ly b e so m ew h at low er th a n th e in flated p ro d u ctio n .

In d u strially , soy is n o t a “w onder b e an ” , no m a tte r how useful th is te rm m ay b e in p ro m o tin g its p ro d u cts. I t is p rim a rily a source of food p ro d u c ts. A m o u n tin g to a m eager

•3% of to ta l p rew ar o u tp u t, th e in d u stria l uses of soybean p ro d u c ts a re n o t im p o rta n t in th e over-all p ictu re. P a in t uses of soybean oil h av e declined because of g re ater dem ands for it as a n edible oil. S oybean sy n th e tic ru b b e r w as an in te re stin g w ar-b o rn developm ent, b u t i t h a d no special a d ­ v a n ta g e s to w a rra n t th e use of a n edible oil for th is purpose S o y b ean plastics are on th e decline. T h e y h av e w ater- sensitive ch aracteristics a n d o th e r shortcom ings w hich cannot b e offset b y price a d v an ta g es in c ertain applications. B y now , p lastics h av e gone b e y o n d th e so y b ean p ro te in stage.

N ew in d u stria l p ro sp ects for soybean p ro d u c ts include iso lated p ro tein s for p ap erm ak in g a n d o th e r in d u stria l uses a n d fra ctio n ated oils on w hich in te re stin g w ork is now being done. S oybeans, how ever, will p ro b a b ly n ev er figure p ro m i­

n e n tly as a n in d u stria l raw m aterial, sim p ly because th e farm er gets too m u ch for his crop for it to com pete against w ood, coal, a n d petro leu m . S o y b ean p ro d u c ts are n o t b y ­ p ro d u cts. Oil a n d m eal will h av e to b e codeveloped because th e in d u s try is n o t in a p osition to o p erate on a b y -product basis. T h e p o stw a r fu tu re of so y b ean p ro d u c ts, th erefore, will co n tin u e to be in edible p ro d u c ts.

I ta lia n R e n a is s a n c e . V ita liz a tio n of th e I t a l i a n ch em i­

cal in d u s tr y is o n e of th e m o s t i m p o r ta n t p ro b le m s facin g th e A llied M ilita r y G o v e rn m e n t. O v er 4 0 % of th e in d u s ­ tr ia l p la n ts of I t a l y h a d b e e n d a m a g e d , m o s tly b y b o m b in g , b u t m a n y also b y G e rm a n sa b o ta g e . L a c k of co al h a s b e e n th e m o st se rio u s ra w m a te ria l s h o rta g e , a n d o n ly w ith g r e a t d iffic u lty h a v e m o st of th e p la n ts b e e n m a d e o p e r­

a b le.

One of th e first to b e reopened w as a chlorine p la n t, for reasons of h e a lth . T h e h em p in d u s try h a s b een b ro u g h t to som e degree of usefulness, m o stly d u e to th e financial sta b ility g iven th e m a rk e t b y th e m ilita ry officials.

T h e a llied co m m issio n h a s s t a r te d six c e m e n t p la n ts c a p ­ a b le to g e th e r of tu r n in g o u t 10,000 to n s p e r m o n th . S u p e r­

p h o s p h a te p la n ts w ere b a d ly d a m a g e d , ow ing to th e fa c t t h a t th e cooling sh e d s w ere f a v o rite m ilita r y sto ra g e u n its a n d , c o n se q u e n tly , f a v o rite ta r g e ts fo r p la n e s. T o d a y th is in d u stry , v ita l to ag ricu ltu re, h as b een re h a b ilita te d to th e p o in t w here i t is tu rn in g o u t a b o u t 200,000 to n s p e r y ear.

M a n y of th e fu rn aces h a d b een d e stro y ed b y th e G erm ans a n d could n o t b e used u n til p la n ts m ak in g a c ertain re fra c to ry cem en t h a d b een re p aired a n d w ere pro d u cin g .

M e rc u ry m in es w ere la rg e ly u n d a m a g e d , a n d a s to re of 8000 flask s of m e rc u ry , h id d e n fro m th e G e rm a n s , w ere u n c o v e re d . C o p p e r s u lfa te fo r in se c tic id e s is b e in g m ad e a g a in a t a r a te of 3000 to n s p e r m o n th ; s a lv a g e d b ra s s is th e ra w m a te ria l.

M a k in g n itro g e n o u s fe rtiliz e r d id n o t y ie ld to a n easy s o lu tio n . T h e G e rm a n s h a d d e c a m p e d w ith a ll th e p la ti­

n u m c a ta ly s t fro m th e C ro to n e p la n t.

Q4kL

O tu b tiito f

22

I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y m

Controlled Exchange. T he application of controllers to chemi­

cal p la n t equipm ent is never easy, since th e m any factors affecting operation an d response yield only to complex analysis or to tria l an d error. D uring th e p a st few years, however, practical applica­

tions have been investigated w ith a view to applying complex theoretical analysis to th e problem s posed. A m ajor stum bling block has been difficulty in th e application of controls to h e at ex­

changers. M ore, Quail, an d B ain have, in th is issue, described some of th eir pioneering w ork in th is field. See “A pplication of A utom atic C ontrollers to H e a t Exchangers” .

O u t of H iding. Censorable articles w hich are finding th eir w ay in to th e lives of th e E d ito rs are being welcomed w ith open arm s because these contributions can now be p u t in p rin t instead of being hidden in .the safe. One article recently o u t of th e cen­

sored sta tu s is th a t of L inn and Grosse en titled “A lkylation of Isoparafim s by Olefins in Presence of H ydrogen Fluoride” . T his process is im p o rtan t in th e m anufacture of aviation gasoline, and we are pleased to m ake th e knowledge available. As inform ation becomes fu rth er declassified, m ore on th is subject will be spread before you.

Explosive Watte. D espite th e m odem techniques for elimi­

natin g all residual T N T from liquids em anating from shell-loading plants, it was found th a t 100 p a rts per million of T N T was n o t un­

common in th e discharged w aters. Since th is was a nuisance of considerable m agnitude for th e stream s in to w hich th e waste was dum ped, research was in stitu ted w ith th e hope of finding an adequate answ er. R uchhoft, LeB osquet, an d M eckler, of th e U n ited States Public H ealth Service, found th a t soil and activ ated carbon absorption bore m ost prom ise as a tem porary w ar measure.

Now, w ith th e ad v en t of peace, i t m ay seem th a t such an article is of little im m ediate value. H ow ever th e chemical plan ts of th e n atio n are going to be faced w ith analogous disposal problems, an d th e resu lts presented here will rem ain im p o rtan t long after th e plants, for w hich th e studies were m ade, are razed.

Bearing U p W ell. Corrosion of bearings b y chemical mecha­

nism s is a t p resen t undergoing interpretive and exhaustive re­

search. P ru tto n , T urnbull, an d F rey, specifically studying th e corrosion of lead b y peroxides, have added to our knowledge of th e basic corrosive reactions in lubrication system s. One of th e im p o rta n t considerations in th e evaluation of th e corrosivity of an oil, according to th e authors, is th e therm al sta b ility of th e oxidizing agent.

A nother Sell in Cellulose. Carboxym ethylcellulose, m ade by reacting m onochloroacetic acid on alkali cellulose, is now intro­

duced com m ercially an d has begun its career of usefulness to th e chem ical industry. H ollabaugh an d B u rt of th e Hercules Pow der C om pany, an ticip atin g a need for inform ation on this com pound, have compiled a com plete sum m ary of its history, properties, an d possible applications. A pparently research team s in m an y industries will spend m uch tim e on th is substance, for th e lis t of applications is lengthy.

Cracking O lefins. G reensfelder a n d Voge rep o rt again on th e cracking of hydrocarbons. T h is tu n e it is th e olefins, a n d th e work was done w ith a silica-zirconia-alum ina cata ly st. R esults are reported an d analyzed.

Bacillus brevis. Chemical Manufacturer. T h e efficient grow th of B re’r brevis is becom ing a first-class problem in chem ical eco­

nomics an d m anufacturing. Brevis is th e chem ical cow w hich gives th e m ilk containing ty ro th ricin . Lewis, D im ick, and F eustel are wondering w hether it can n o t be done b e tte r in shallow- layer grow th on a c u ltu re of juice m ade from asparagus b u tts — a w aste product of food canning. According to th is report, yields am ount to as m uch as 2 gram s per liter, which, th e y say, is g reater th a n any reported so far.

Boil and Bubble. Liquids, like hum ans, boil a t different degrees an d for different reasons. L arsonr in “F acto rs A ffecting Boiling in a L iquid” , investigates a phase of u n it operations t h a t has been som ew hat neglected, an d arrives a t conclusions t h a t will be help­

ful to th e designers of h e at exchangers. W orrying th e facts of nucleate an d film boiling, he b u ilt a n a p p ara tu s for testin g ebul- lators or bubble m akers an d found t h a t m etals of different com­

position seemingly produce different ebullition tem p eratu res.

One of his conclusions is th a t ebullition does depend upon a n aid whose p ro p erty determ ines th e a m o u n t of su p erh eat tolerated.

Following th e p ap er th e sam e a u th o r investigates a n d discusses therm odynam ically th e reasons for bubble form ation.

Design Data. N oting th e increasing p o p u larity of continuous solvent-extraction m ethods for vegetable oils, Pollard, Vix, and G astrock, of th e S outhern R egional R esearch L ab o rato ry , are publishing d a ta on boiling p oints a n d densities of cottonseed and pean u t oils m ixed w ith hexane. T h is is im p o rta n t to th e design­

ers of vacuum evaporators an d strip p ers used in th e extraction processes.

Plastic Intermediate. Aconitic a6id m ay be used in acrylic res­

ins as a modifier; its esters e n te r a v a rie ty of chem ical m aterials, and its decom position pro d u ct, itaconic acid, can, th ro u g h esters, be used as a plastic. W ith all these uses, aconitic acid should be popular w ith th e chem ical fra te rn ity ; U m bdenstock and B ruins report on th e cataly tic deh y d ratio n of citric acid to m ake th is interm ediate.

W ith the Departments. Von Pechm ann senses th e confusion which has existed in m an y p lan ts in th e swing to peacetim e p ro ­ duction and suggests th e planning of sound policies. M urdock exam ines th e th ree areas available for th e disposal of in d u strial wastes. B row n sees t h a t m an y new w artim e p ro d u cts will be im p o rtan t to in d u stry in th e postw ar. M unch w rites th e ch ap ter an d verse on th e application of s tra in gages to pressure measure»

m ent.

RIAL ^{a n d} E N G I N E E R I N G CHEMISTRY

B L I S H E D BY T HE A M E R I C A N C H E M I C A L S O C I E T Y

W A L T E R J. M U R P H Y , E D I T O R

A S c ie n tific C redo

F OR years the editors of

have urged the chemists of the Nation to show an active and intelligent participation in the affairs of the world.

Decrying the ivory tower of science, and begging the chemist to assume responsibilities in our everyday world, we have pointed out many, many times th a t the course of civilization could be better directed if the ap­

proach of science were among those many arts and di­

verse forces th at today mold our public opinion.

Now we notice th a t the anthropologists, too, are be­

ginning to become interested in this aspect of living and Dr. Gene Weltfish, of the Departm ent of Anthro­

pology at Columbia University, in the September Scientific Monthly has written a stirring and moving plea for cooperation by scientists in our everyday af­

fairs. Miss Weltfish states th at some years ago, while attending commencement exercises, she heard the medical graduates recite the Hippocratic oath. She was impressed by its solemnity, but even more striking was to her the fact th at the only group of graduates th at was asked to express any public responsibility were the physicians.

She abhors the disinterestedness of the scientists, stating th at it amounts to a lack of evaluation of pur­

poses, and th at as a consequence the scientist can read­

ily become the creator of havoc and destruction. For our reconstructed world she thinks th at graduates should take cognizance of their responsibilities and the social consequences resulting from their use of scientific techniques. In order to make them conscious of their obligations she proposes a simple yet moving oath which she titles “The Scientist’s Oath” , and which we pass on to you because of its importance in the thought currents th at are stirring us today.

“I pledge th at I will use my knowledge for the good of humanity and against the destructive forces of the world and the ruthless intent of men; and th a t I will work together with my fellow scientists of whatever nation, creed, or color, for these, our common ends.”

This is an im portant suggestion. Perhaps what is needed is some simple impressive ceremony which will bring to our scientists a deep understanding of their responsibilities and their great potentialities.

M ankind has had a narrow squeak in the war th at has ju st ceased. Under the wrong sponsorship, science had become, in the totalitarian countries, something awful to behold. W ithout proper guidance from men of gen­

erous outlook, science can become, in any part of the globe, a force of evil.

Winston Churchill expressed it early in the war when he said, in speaking of the yearning need for victory,

“if we fail, then the whole world *** and all th at we have known and cared for will sink into the abyss of a new dark age made more sinister, and perhaps more pro­

longed by the lights of a perverted science". Vision is the need, for without it the people will surely perish.

Revising N a tio n a l Defense

t > EPRESENTATIVE Arends of the State of Illinois has introduced a bill in the House of Representatives, Resolution 4152, for the establishment of a “commis­

sion of national defense to study the technological revi­

sion of our national defense necessitated by atomic and other weapons” . To us, an appealing and admirable feature of the proposed act is that it makes provision for the commission to be staffed by “representatives of scientific and industrial research and other leading citi­

zens who are conversant with the problems of the na­

tional defense” . This group will be advised by military representatives who will give the commission full ac­

cess to the facts relating to technological revolution in warfare. The commission, in turn, will make interim quarterly reports to Congress so th at an adequate na­

tional defense program may be formulated. A fund of a half-million dollars is also recommended to enable the study to be carried out properly.

This proposal constitutes a step in the right direction.

Our Nation has had a long-unfilled need for the services of scientific men in the executive direction of national defense and other problems of government. At long last this may come about, provided the bill is passed;

but only because science has, with a new weapon of unsurpassed magnitude, contrived to impress upon the minds of the legislators the necessity of expert and ade­

quate advice in this field. We hope not only for the passage of the Arends bill but also th at many more proposals such as this one, providing for the cooperation of science, are introduced into the Congress of the United States. Science with its varied talents for research and investigation into the basic facts and laws underlying our civilization has much to offer, and we sincerely hope th at the time has come for the com­

plete recognition of this fact—and for its application, in a practical way, to this age and to its problems.

911

A n o u t lin e is p resented o f t h e m e t h o d s used by Ziegler an d N ic h o ls for fin d in g t h e o p t im u m s e t t in g s for t e m p e r a ­ tu r e c o n tro llers. Applied t o a h e a t e xch anger, c o efficien t u t o be used in t h e s e n s itiv ity e q u a tio n , 5 = u /R iL , w as d e te r m in e d b y t h e reaction or response curve m e th o d . T h e w ork w a s carried fu r th e r by c a lc u la tin g t h e va lu e of t h e c a p a c ita n c e s o f t h e e x ch a n g er w h ic h c o n tr ib u te t o t h e fo r m o f t h e resp on se curve and by gra p h ica lly r ec o n s tr u c t­

ing t h i s c u rve. C oefficien t u f o u n d by t h i s m e th o d c o m ­ pares favorably w it h t h e v a lu e d e te rm in e d e x p erim en ta lly .

T

teristics, h ave resulted in a m ore system atic stu d y of practical applications. T he object of th is stu d y was to devise m eans of determ ining optim um controller settings for th e various conditions of lag a n d capacitance w hich m ake u p a n in d u strial process.

T h e w ork of Ziegler an d N ichols (4) resulted in th e develop­

m en t of th ree m eans of determ ining optim um controller se ttin g s:

u ltim ate sensitivity, response curve, a n d analytical response curve m ethods. T h e w ork described here w as perform ed (a) to determ ine constants applicable to th e response curve m ethod w hen used to determ ine optim um settin g s for industrial h eat exchangers, an d (6) to ev alu ate effects of th e various design fac­

to rs of h e a t exchangers on th e controllability of th e process and th u s m ake possible th e application of th e an aly tical response curve m eth o d to problem s of in d u strial h e a t exchanger control.

T h e u ltim ate sen sitiv ity a n d response curve m ethods for de­

term ining au to m a tic controller settings a n d th eir application to a d istillatio n process were rep o rted b y Allen (1). T hey will,

therefore, be described only briefly in th is p aper. G enerally, the m o st desirable controller settin g for a given process is th a t a t which th e recovery curve o b tain ed a fte r a n y d istu rb an ce of th e equilibrium of th e process shows a n am p litu d e ra tio (ratio of m agnitude of each oscillation to t h a t of th e oscillation preceding it) of 25% . T herefore, th e th ree m ethods described below are in ten d ed to indicate th e proper controller se ttin g to give th is 25%

am p litu d e ratio.

U LTIM ATE SE N SIT IV ITY AND RESPONSE CURVE In m o st processes a controller sen sitiv ity (o u tp u t change per u n it of pen m ovem ent) of one h alf t h a t a t w hich a n am plitude ratio of 100% is obtained (u ltim ate sen sitiv ity ) gives a recovery curve having a n am p litu d e ra tio of approxim ately 25% . T here­

fore, to determ ine th e optim um se ttin g b y th is m ethod, it is necessary only to find a sen sitiv ity a t w hich su stain ed oscillation results from a process distu rb an ce a n d se t th e in stru m e n t a t half of th a t sensitivity. T h is m eth o d is applicable only to m ultiple- capacity processes, b u t as m o st in d u stria l processes come under this classification, no g re at d isad v an tag e is presented. T he only draw back to th e use of th e u ltim ate se n sitiv ity m eth o d lies in th e tim e required to m ake th e necessary tests. I n large-scale processes having large capacities, th e period of oscillation becomes very long, a n d determ inations are tim e consum ing.

T h e response curve for a process is o b tain ed b y suddenly changing th e flow of th e control a g en t a n d p lo ttin g th e resulting changes in th e controlled variable on a tim e base, in th e absence of a n y controlling action. I n p ractically all in d u stria l processes th e response curve is S-shaped (Figure 1). A ta n g e n t draw n th ro u g h th e p o in t of inflection gives a n in d icatio n of th e charac­

teristics of th e process a n d serves as a m eans for determ ining optim um settin g s for its control.

912

J. u. MORE

| STE. ANNE PAPER COMPANY, BEAUPRE, QUEBEC, CANADA

F. J. QUAIL. AND J. W. BAH

u K iv e f t s ir y o ft o r o n t o, Ca n a d a

P h o to g ra p h s o f t h e E xperim ental H eat E x c h a n g e r S e t u p

W hen a u n it change in th e control ag en t is m ade— e.g., th a t caused by a change of 1 pound per square inch in a ir pressure on a diaphragm valve— th e pro d u ct of th e slope of the tan g en t to the point of inflection of th e response curve, R i, an d its in tercep t on th e horizontal axis, L, gives a direct reciprocal relation for the determ ination of optim um sensitivity of a controller applied to the process. L, th e lag, is approxim ately constant for th e proc­

ess, regardless of th e change m ade in th e flow of th e control agent; th e reaction ra te varies directly as th e change m ade in th e flow of th e control a g en t a n d m u st be converted to a u nit reaction ra te in optim um setting determ inations. T he product, RiL, for a process is represented by th e in tercep t of th e tan g en t through th e p oint of inflection w ith th e vertical axis.

Although th e response curve m ethod gives a direct reciprocal relation for determ ining optim um controller settings, m any industrial processes require a facto r to be applied to th e RJL, values. T he general form ula for obtaining optim um settings from response curve is:

£ = u /R iL

where it is a co n stan t w hich m u st be found experim entally for the various ty p es of processes. Values for u have been reported as high as 5.4 on pure tw o-capacity processes, although m ost industrial processes show a value nearer unity.

T he response curve m ethod has one disadvantage in practice:

I t frequently requires a relatively large disturbance in th e process, an d such disturbances cannot be m ade in m an y processes for practical an d economic reasons.

ANALYTICAL RESPONSE CURVE

Ma t h e m a t i c a l An a l y s i s. T his m ethod involves calculation of th e response curve from calculated values of capacitance, resistance, an d tran sp o rt lag w hich m ake up th e process. This determ ination m ay be either by purely analytical m eans or by graphical m ethods.

C alculation of analytical response curves m ay be illu strated by considering a pure tw o-capacity process. Figure 2 shows a process in w hich th e w ater in ta n k I is heated directly by a steam jet, an d th a t in tan k I I is heated by th e overflow from ta n k I.

Assuming perfect mixing in b o th tan k s and neglecting th e small resistance of th e th er­

m om eter bulb an d th e tran sp o rt lag be­

tw een th e two tanks, we have a sim ple two- capacity process.

If th e system is a t equilibrium a t a tem ­ perature, T 0, an d th e steam flow in to ta n k I is increased so as eventually to establish a new equilibrium a t a tem perature, T , the behavior of th e tem p eratu re in ta n k I I w ith respect to tim e betw een th e tw o sets of equi­

librium conditions constitutes th e response curve of th e process for th a t change in steam flow. A pplication of N ew ton’s law of cooling, which sta te s th a t th e ra te of tem perature change is proportional to th e difference betw een th e tem p eratu re a t any

913

in s ta n t a n d th e u ltim ate tem p eratu re, m akes it possible to cal­

culate th is curve.

L e t t = tem p eratu re a t an y in s ta n t in ta n k I T = u ltim ate tem p eratu re

To = in itial or d a tu m tem p eratu re Kx = tim e c o n stan t for ta n k I, m in.

K 3= tim e co n stan t for ta n k I I , m in.

9 = tim e

T h en for ta n k I, N ew to n ’s law m ay be expressed as follows:

dt/dd = ( T — t ) /K i

~ y _ ~ = do I K ,

In teg ratin g ,

- l n ( T - i) = e/K y + C,

w hen 0 = 0, 6 / K x = 0, an d t = To. Therefore Ci = —l n ( r - To) an d - I n (T - t) = e / K i - ln(5P - To), w hich becomes

ln ( T - To) (T - t) T - t

e / K x

e~0/K>

T - To

o r t = T - (T - To)e-e/Kt

L e t T — To = a; th en

t = T — ae~e/

(1)

w hich is th e equation for th e tem p eratu re of ta n k I a t an y in stan t.

C onsidering ta n k I I ,

de

t - t' K 2 w here t = tem p eratu re of ta n k I

t' = tem p eratu re of ta n k I I K t = co n stan t for ta n k I I

b u t

K id t' = tde - t'de t = T — ae->/Ki (from E q u atio n 1)

.'. K 2dt' = Td6 — ae~o/Kidß — t ’dO

K zdt' — (T — t')de — ae-0/Ku16

(

)

w here V a n d 0 are variable. L e t t ' — T = x, and e~e^Kl = y.

T h en ,

dt' = dx

an d

e~e/Ki d$ = —K idy de =

t h e n K 2dx = x K i — + aK idy ( f r o m E q u a t i o n 2 ) V

K

L e t K i / K i — b a n d m ultiply b y n y n_1; th en , bnyndx — n x y n~ ldy — n a ynd y = 0 L e t bn = — 1,

n = — 1/b and

In teg ra tin g ,

—d (ynx) -

n + l »«+i = 0

b u t

x y n H---~r"T vn+1 = Ci W T 1

~ na

■x = C , y - - ^ T 1 y x = t' - T y = e—

1 _ K i w --- 6 “ iC2

" ~ n = f i

n K i

(3)

71 + 1 -Kj ~ -^1 S u b stitu tin g in E q u atio n 3,

t' - T = C 2 „ g i a „ - e“ « /* »

ii.2 “ A 1

= c , (« - * /* ) + ' ^ T K l 6-6/Xl

and f ' = r + C2e - « / ^ + K \ d

K z - K i e~B/Ki (4)

Ct can be e v alu ated from th e fa ct th a t, w hen 6 = 0, t ' — To.

R a n d L can be calculated from E q u atio n 4, b u t th e m eth o d is cumbersome. T h e a d d itio n of a th ird cap acity fu rth e r com­

plicates th e final equation, a n d its usefulness disappears.

Gr a p h i c a l An a l y s i s. T h e su b s titu tio n of values in complex equations can be avoided b y graphically constructing response curves of processes whose tim e co n stan ts are know n. Such curves (Figure 3) are close enough approxim ations to th e tru e response curves for optim um settin g determ in atio n s a n d are m uch m ore convenient th a n th e pu rely m ath em atical analysis.

Figure 3 was draw n for a three-cap acity process w ith tim e con­

sta n ts of 4, 4, a n d 8 m inutes.

C urve I represents th e response of th e first capacitance (K i = 8 m inutes). If, a t a n y tim e during a change in tem p eratu re, th e tem p eratu re is allow ed to rise a t a co n stan t ra te ra th e r th a n a t a ra te proportional to th e tem p eratu re difference, th e tem p eratu re curve becomes linear. C urve I w as constructed b y im agining a series of co n stan t-rate tem p eratu re rises over sm all tim e in terv als;

i.e., A to B m ay be prolonged to C w here th e tim e betw een C a n d C ' (where C ' is th e average tim e during th e change A to B ) is 8 m in u tes ( = K i). T im e increm ent A to B is 1.0 m in u te.

T h e n ex t a d d itio n to th e curve s ta rts a t B a n d is aim ed tow ards E . T h is a d d itio n is represented b y BC , th e average tim e is rep­

resen ted b y p o in t E ', a n d th e tim e from E ' to E is a g ain eq u al to K i, th e tim e co n stan t for th e first capacity. E ach of these sh o rt lines approxim ates th e corresponding p o rtio n of th e ex­

p onential curve w hich w ould represent m ore tru ly th e response of a capacitance having a tim e c o n stan t of 8 m inutes.