a37
INDUSTRIAL AND ENGINEERING CHEMISTRY
July 1947
CONCLUSIONS
Total Incubation a t 550 c . Days
dtyrene. 1\11.
. ..,.
4 4
1u
0 L'
U 0; g. dry
... ...
1
0 07 g . ? d r o p
1
2 n i l . of 2Cc aqueous .oln.
4
4
1111.
nater
'
4
1
,..
11 em arks
1
Conipletely popped
> >340
Completely popped Styrene fluid
> 104
Styrene fluid
Irion strip
> 135
Styrene slightly viscous 60 days Styrene fluid
Iron strip
>113
...
>113
of lC; aqueou..
ioln. '%(I
2 i I r n l . of 2',
aqueouy
ioln. 10 4
...
>I21
Iron strip
20 1 i i 1 . of 2'3 aqueous silln.
>I21
Styrene slightly v i s cous 100 days Styrene -lightly v i s cous 100 days
2 n i l . uf 1';
>121
Styrene fluid
>151
squeous
iOl11.
Iron strip 1IJ
0 2
4
41111.uf O.jL; soh
Ill
0 2
4
8 riil. of 0.2jc;
aqueous
Iron s t r i p aque-
ous < o h
4
Styrene fluid Styrene fluid
,
2 1111.of 0.5'& aqueou3 aoln.
i r o n .trip
7
t a n k , a n d t h e styrene elid of t h e decanters. Tlie concentratioria of sodium nitrite in each location follow: booster condenser (decanter water), 500 p.p.m. on t h e v-ater; butadiene condenser (recycle butadiene), 500 p.p.m. on t h e butadiene; decanters (recycle styrene), 500 p.p.m. on t h e styrene; vacuum flash tank, 600 p.p.rn. on t h e monomers in t h e latex. % . 21% solution of sodium nitrite is pumped t o t h e recovery buildings n-here it is measured by rotameters t o t h e varioup addition points. T h e decanter Ii-ater from t h e recovery units.. containing 500 p.p.m. eodiuni nitrite, is used in making soap wlution for reactor charging. T h e use of this 11-ater has had no detrimental effects on t h e polymerization. T o date there has been no increase in t h e peroxide content c i f recycle butadiene. T h e peroxide content a t present is approsimately 5 p.p.m, If there should b e a n increase in peroxide content above 10 p.p.ni., we plan t o add teri-butylcatechol t o t h e recycle butadiene a t t h e t a n k farin. .4t present tert-butylcatechol is being added only t o ~ h i p n i e n t sof recycle butadiene and styrene. Tlie t w t s described iridicate t h a t sodium nitrite solutioiia :ire iluite effective as inhihitor> of popcorn seed growth in many piirth of ropnlymer pl:ints.
The growth of popcorn ~iolymer can be prevented either by seed deactivation with nitrogen dioside or by inliibitioii with aqueous sodium nitrite. The best procedure for effective industrial control i-. prohably a combination of both methods-that is, deactivation with nitrogen dioside followed by the continuous addition of sodium nitrite to prevent the formation and growth of n m seeds. ICKNOWLEDGRI EST
The work reported iii this > 121 Styrene viscous 100 paper was done in connection daw >113 Styrene fluid with the Governnient Research Program on s:!-iitlietic >113 Styrene >-iscous 11:3 days lubber under contract with the >I13 Styrene fluid O R c e of Rubber Reserve, Re>113 Styrene visroua 15 construction Finance Corporndays tion. The authors wish to Styrene par:ly 17 popped iicknoa-ledge their indebted17 Styrene partly riess t o J . J. Cunningham, popped of the Office of Rubber Reserve, for his encouragement and interest and for liaison work n i t h the iiidu.tries;. Thry also wish t o express appreciiition t o James Ie P-L7-7' behavior roiiicidec with tlizt of tlie niisture in tlie ..iil)ri~he:ited region. Thr. priidocriticnl point does not, i n gene-
1x1,coiiicide with tlir tiuv criticd puint of the niisture. I%:i;.ed on the pseudocriticnl point, thtr compresqibilities of tlw g:i> inistiire mny he c:tlcul:itrd from p-charts ( p = Z'l. ' t i K 7 ' ) \vllich linve been tieveloped irum measuremerib oii purr g:iws, I ii.tcd of :I p-chart, it- :indytic:il ~qiiiviileiit--:i genernlized eqwtioit of >t:ite-ninl- he w e d , n s piiiiitcvl out 11y Su, Hu:ing, :iii(l ('11:iirg (10).
Kay >ugge?ted that, at k i s t iiir niiztures (JI' tlie loiver llytiroc~:irboii., the pseudocritical teniprr:iture, T,, arid the p ~ i i d o rritical pressure, P,, of the niisturr may l i e ohtnined n-itli y i i f f i -
cient accuracy from the i ~ ~ I : i t i ~ i i i ~ ,
a38
INDUSTRIAL AND ENGINEERING CHEMISTRY
:ire the critical temperatures, and P,, P,, etc., are rhe critical pressures of the components. This proc d u r e for calculating the pseudocritical constmts i s designated as method I.
(7 ) 50 7 1 221 21-121 70
I .i
10 5 5
io
(8'1 60 0 200 55-90 45
18)
191 100-300
"72 :38 2 R X 70
.50 48 250 25-125 00
P.6i
.> 63
2 07
3.03
1 83
,I
~~,U~~~~~~~lsatt%olllp"lirlli 5 0 44
M a x . pressure, atni Temp. range, ' C
so.of oointa
l l e t h o d I. 4v.
Vol. 39, No. 7
' 2 deiiutiiiit
Iiay's method xas studied by Su, H u n g , aiid Nax. 10.2 i:A8* 6.14 , .a4 :1 7 5 ( ' h n g ( I O ) wit,h the aid of compressibility data on A\Iethod I L , , 2 26 2.66 2 04 Av. 4s different gas mixtures, and gave results of mfNax. 8 80 4.66 .i 20 ficient accuracy for many engineering pur~poses. Method I l l , L i d p \ i a r i u u The restriction of the method to 1iydroc:whon misAV. 1.OY 1.62 1.44 2 26 1 07 hlax. 8 19 4 17 4 OR 4.59 i3.17 tiires appears t o be removed hy the Lvork of Su, Hiinrig, and Chang. Furthermore, they pointed out t Iiat there is a similarity hetween Bay's method and ,.I C /'e = x:7'1,'1'1 -t .r"'?''P? + ' 4 . 1 7 ' 1 11' 1 1'1'2 1'2)' J j , j J l & ttle usual method of combination of equation (if state constarlts. i 7B) The purpose of this paper is t o show that the assignment of :t liseiidocritical temperature and pressure t o the mixture is entirely 'rhe calculatioll pseeudocritical corlstallts ill L,ccol,ci:ill(Lt~ ,viti, iwii&tent with the method of combination of equation of state nlptllod 111, ~ q u a t i o l l s7 and 7~ is desigllated ccinst:ints, and t o develop a n e x method for calculating the .iltliough the vtin der Waals equation was u i e d tu derive 1:quapseudocritical constants of a gas mixture. For the sake o f 7R, the same equation> mny he obtained from the tions 7 , 7-4, ~11d 4mplicity a binary mixture will be considered. The results :ire, B!,ill the BeattielIpuLL]nleth& o f coi~it)initigcoIlst:LIlto '.I,, however, easily extended t o a mixtire of any Iiumber of rc~niif these constarits elidHiidgeIn:ir, equ:+tioll state ( 1 , Tionents. iiated in t,erms o f the generalized 1~r:ittir-Rridgem:in coristants The van der Waals equation of state Rill lie assumed as the .4; aIl(i~d (9) wllcl tile critical teInl)er:iture;. lLlldpreRsilrea. equation of state for the individual components and for the gasTo determine whether, in the ciilculatioii of pseudocritical ~ O U Smixture. T h e usual method for computing the van der n l ~ ~ t h111 o ~would ~ yield resu]& constants, either niethod 11 Waals constant, a, for the mixture from constants and u.2 nf 1,f greater accur:icy than method I, tlir three methods n-ere tested the t,wo components is in accordance with the relation, against P-T'-T d a t a on five diffclreiit 1)in:iry g ~ q mix-tiirea. For mixtures in which the T , ' P cratios of t h component gt*.es do not a"a = ala:" xnn:'2 l 21 differ grehtly, methods I1 and I11 >+id : h o s t identical results. T'wo different methods have been in general use for evaluating For t,his reason method 11 war not tested separately in t]le cme constant b of the mixture ( 1 ) . One, suggested hy van der 'A-aals, of the methane-.c;+rboll dioxide and the carhorl (lioxide riit)rogeII leads t.0 the relation, tems, The pseudocritical conatanb of the misturp and the tahulated experimental values of temperature and pressure were b = ~ i b l x2bz wed iii each case to compute the reduced t,emperatures :ind pres-l'tie other method, derived with tlie :lid of kinetic theory I)?. ~urefi. T h e compppsihility factor!: ryere then obtained from a imrentz (6)1involves the relation, @-chart (11) and their valuer compared with the ohserved values of the compressibility factor. Table I shows t h e results of this ,4, b = x:bi xiby ' j , ( b f ' 3 f b: ' ' ) ' ~ i t , : iriveatig:Iti(iii, :itid indicates that,, for all mixtures inveatig:tted, VXII der JVaals constants for the individual components may he metilod I I r i. Inure :iccur:ite than Kay's original method vxpressed in terms of their critical temperatures and pressurw in (methl,tl I ) . 111:ill c:+~e*5vher.e method 11 yielded results signifi:iccordance with the well known relations, cauntly different from those of method 111, the latter v-w found to the more accurate of the two. ai = 27R2T,2/A41', :dl 1Iett111tiI11 may be used to evrtliurte the pseudocritic:il conbi = KTiI8Pi *taiits of :I g:iti misture of :my number of components.. For a inisturr lit' rt components, Equations 7 and 7B may tw conl$y analogy with Equation 5 , ~ v e:i.*s1inie For (*orlst:Ints (I :1titl i, veriientl>. w i t t e n i n the form, tf' the mixture the relat,ions,
..
+
I
z),
+
+
+
+
t)cA
1
a = 27K27'1/641',
b
=
ti1
7 7 ,
.1.,
(Ah'
KT,/8Pc
E:yu:ctions 6 and 6A define t h e pseudocritical constaiits of :I yus mixture. On substituting Equations 5, 6, and 6-4 into Equ:itiuw 2 arid 3, tlie following relations are obtained:
Equations 7 and 7A may he used like Kay's Equations 1 to conipute the pseudocritical constants of the gas mixture. The calculation of pseudocritical constants in accordance with Equation. 7 and 7 8 is designated as method 11. If, however, Equations 5, 6, and 6A are substituted into Equations 2 and 4,the following relations are obtained:
7', 'P!' 2
=
.rl7', 1':
-
i
'Pi
'
-, '
f',
I
,I>; 1
,
=
,., z,y-i
'/>I
i ?
i
-A
8 ~ . \ ~ . r . T ( ~ l ~ 3 ' f 1> l dt-1. I L 3
,
+
7.;
8;p;:3,'
