Forest Products Laboratory (U.S.)

Schwartz, Sidney L.

Undetermined

ScholarsArchive@OSU

SD4 33U5-2-.1q“,	 THE VISCOSITY-TEMPERATURE-TOTAL SOLIDSRELATIONSHIP OF SULFATE BLACK LIQUORSOctober 1942No. 81416UNITED STATES DEPARTMENT OF AGRICULTUREFOREST SERVICEFOREST PRODUCTS LABORATORYMadison, WisconsinIn Cooperation with the University of WisconsinTEE VISCOSITY-TEMPERATURE-TOTAL SOLIDS RELATIONSHIP OF SULFATE' BLACK LIQUORS BySIDNEY L. SCHWARTZ,Assistant EngineerSYNOPSISSulfate black liquors increase in viscosity with increased concentration.Above a totall solids concentration of 40 percent, the viscosities of theliquors rise rapidly with increases in concentration, but are markedly de-creased by increases in temperature. At concentrations of less than 40percent the viscosities are, relatively sneaking, not much greater than thatof water, and the effect of temperature is relatively slight.INTRODUCTIONIn the evaporation step incident to recovery of chemicals from sulfate blackliquors, the liquors are usually concentrated in multiple-effect vacuumevaporators to total-solids contents ranging from 55 to 6o percent. Inthis evaporating process the flow of the liquor and the transfer of heat tothe liquor are two problems confronting both the equipment designer and theoperator. Since the viscosity of a liquid is an important factor (5) inboth of these considerations, the investigation reported here was undertakenwith the objective of measuring the viscosity changes which occur withchanges in temperature and concentration of several sulfate spent or blackliquors.MATERIALS AND PROCEDUREThree black liquor samples, designated as liquors A, B, and 0, were studied.Sample A was a commercial sulfate black liquor secured from a "Wisconsin mill.Sample B was a laboratory seMicommercial loblolly pine sulfate black liquor,and sample C was a laboratory semicemmercial jack pine sulfate -black liquor.As these black liquors resulted from various cooking conditions, they canbest be characterized by the„ data in table 1.Mimeo, No. R1416	 -1-Several samples of each were evaporated on a steam bath. Total solids ofthese samples were determined and several batches of each liquor of varioustotal solids content were prepared from the concentrated liquor. In caseswhere the concentrated samples were used prior to making more dilute solutions,the total solids co:Aent of the samples so obtained was determined. In nocase was the concentration of a liquor carried beyond 60 percent of totalsolids.,The total solids were determined by means of a modification of the Methoddescribed by 0-iffin (2): A sample of black liquor (20 to 50 cc. dependingon the approximate -..)Lcentrain of the liquor) was weighed, diluted to 500 cc.with water in a -vo,Llaatri: rusk; . and mixed thoroughly. A 50-cc. aliquotwas run into a weich'd IOC 'mil: porcelain evaporating dish, evaporated, andthen dried for 16 hoars (Over night) at 105 u C.The purpose of vary4.ng the size of the samples weighed out was to securecomparable reg idral sarples. A liquor con:,aiming slightly less than 20 per-cent of total :.ol:Os will yield a residual sample that approximates 1 gramwhen a 50-cc. weighed saml,e is taken. 	 :VThere is a tendency towards :polymerizationand carbonization of-the organicmaterial	 black liquor which - occurs cn eva-po2atnfT, especially at high.temppramrec., In ihe Dreoelice of alkali(6) . In reog y,it i_Jn of this fact asample of liquor L was concentrated by vascout	 ana usea as acontrol.The relative viscosities of the black liquors"were-deterthined by means ofan Engler vis ,..:Ometer	 This was accomplished b5 measuring the time of effluxof 200 ec. of each liquor through the orifice of the instrument. The timeof efflux for 200 cc—of water at 20° C. th•cugh a standard orifice on theEngler is,51 seconds (3). The relative vis-:o:,ity cf any liquid at ,anytemperature to that of water at 20° C. may bd comp:Lted by dividing its timeof efflux in secona': by 51. This is called the "Engler number" or "Englerratio," and all the viscosity data secured were so computed.The absolute viscosity may be approximated from the following formula (3)for an apparatus of normal dimensions: 	 -i 71(0.001435T _ 3.22/T)where 1 = coefficient of viscosity in C.G.S. units.T = time of effluxof'200	 .specific gravity a:t'the temperature in ,que-stion.For this reason the specific gravities of the various liquors , at the varioustemperatures encountered in this study were determined. A. sUitable tempera-ture control apparatus for determining specific gravities at various tempera-tures was provided by inserting a porcelain disc in the viscometer pan uponwhich to rest the small, 5- to 10-cc. pycnometers. Water in contact withMimeo. Do. R1416	 -2--the pycnometer in the viscometer pan was allowed to come to a equilibriumwith the temperature of the bath and kept there for 10 minutes. Thepycnometers, clean, dried, and desiccated, were weighed. The specificgravity was determined relative to water at 20° C.The range of total :solids .coVered was from a3.5 percent to 59.7- percent. Thetemperature range was from 20" to 960 0.:RESULTS AND DISCUSSIONThe vis cosity-temperature-specific gravity data for liquors.A, B, and 	 atvarious degrees of concentrations, are recorded in tables ,"2; 3, and 4, andplotted graphically in figure I. The data show that the viscosity of blackliquors at 20° C. increased with higher concentrations. The increase inviscosity was especially rapid for total-solids concentrations above 40 .percent. The viscosities of the liquors above 40-peroent total solids weremarkedly affected by increased temperature. ko concentrations-below 40-per-cent total solids the viscosities were, relatively ?peaking, not much greaterthan that of water, and the effect on viscosity , due to increase in temperaturewas comparatively slight.- Moore (4)--reported a similar viscosity-temperature-total solids relationship for sulfite waste liquor obtained with a Stormerviscometer.The viscosity-temperature-total solids relationships of the three liquorsstudied are characterized by the curves in figure 1.Differences in the viscosities of the three liquors are apparent. The vis-cosity of liquor C above 43 percent of total solids was definitely higherthan the corresponding viscosities of the other two, as shown in-table 2.The viscosity of liquor B for all degrees of concentration was comrarativelylow at 20° C. Anomalous-'results are evident, however, and may be attributedto errors in total solids determinations, irregularities in temperaturecontrol, and changes in total solids resulting from the variations in timenecessary to bring the temperatures of the various solutions into equilibriumwith the temperature-control bath. The latter is an important factor at highconcentrations, for a slight change in total solids in a solution containingapproximately 60 percent of solids will bring about a marked change in vis-cosity.It is difficult to attribute the individual viscosity characteristics toindividual characteristics of the liquors. Though differences in the freealkali content, the heat value of the residue., and the ratio of ash to totalsolids, as shown in table 1, existed in the original liquors, the trend ofthese variations cannot be correlated with viscosity.An attempt was made to duplicate results obtained for several concentrationsof liquor A. A sample was concentrated by evaporation on a-steam bath and,upon being tested, showed a total solids content of 57.0 percent. Thissample was designated as sample No. 11, from which samples No. 12, 13, and 14,corresponding to 54. g-, 51.0-, and 47.3-percent total solids were prepared.Mimeo. No. 81416	 -3-Viscosities were determined and the results, as plotted in figure 1, did notCorrespond with previous results. Total solids determinations on all,samplesrevealed that they did not check with the calculated values. Further testsshowed that variations of ± 1.0 percent in total solids could be obtained..A4 these determinations were run in batches which included all the samplesin question, the variations may be definitely attributed to day-to-dayvariations in the temperature of the drying oven, which was set for 105° C.Temperatures as high as 108° C. were observed. Furthermore, the errorsProduced by the variations of temperature in the oven would be greater atthe higher concentrations because of the method of sampling.Sample No. 4, liquor A (47.3-percent total solids), which was prepared_ byvacuum distillation at 36° C., was found to have practically the same vis-cosity as sample No. 10, which was prepared from a concentrated steam-bathSample. Further rork on vacuum-distilled samples was discontinued becauseprior work at the Laboratory indicated that the viscosity of sample Yo. 4was in the range of viscosities of samples obtained by other means of evap-fration (table 3). Furthermore, viscosity data made available to the Lab-oratory by Babcock-Wilcox and Company (table 4), determined by the Saybolt-furol viscometer, are not, though similar in character, comparable to thedata obtained. In view of the above considerations, further work on vacuum-distilled samples. does :lot apicedt.Warranted.Moreover, in regard f6 technical Viscometers such as Saybolt, Savbolt-furol,Engler, and others; Bingham (1) had little to recoMtend. They are inaccurateand have many sources of error, , In the case of the tnglet when calibratedwith Water at 20 6 di% the kinetic-energy correction amounts to 90 percentof energy expended% The viscosity in. this particular cast has but littlepart in determining the rate of flow.BIBLIOGRAPHY(1) Bingham, E. C. "Fluidity and Plasticity." 1st edition, 2a impression,page 324 (1922)%(2) Griffin, R% C. "Technical Methods of Analysis." 2a edition, 2d im-pression, page 392 (1927).(3) Higgins, W. F. Jour, Soc. Chem. Ind., Vol; 32, page 572 (1913).(4) Moore, H. X% Trans-Am. Inst. of Chem. Eng., Vol: XV, part II, page 240.(5) Walker, tewis, and McAdams. "Principles of Chemical Engineering."2d edition, pages 73 to 192 (July 1927).(6) "The Manufacture of Pulp and Paper." 3d edition% volume III, part 5;page 99.Mimeo. No. R1416	 -4-.	 co0 W	 ri ,C:5	 LC1	.,-1 cd 0 0 ,--t	 4-I-)	 4-, -OA r---I	 *'A 8	 4-) En.	0 0	 0..	 ..	 ..	 ..	 .tri	 1 	 41 1	 r..-%Acd-i C..)	 r-1ti•• •• ••	 •• •• .• •• •• •• ••••iecd0-0•H+acdS.•04.)41.cti4-)c1:5rdF4a)4-)041=Icda)0rire•El00	 0,1,	 • •	 ••	 • •C) 0 s.-4CIr-I • k .1=1,-d . d1	 •• HFR 4-5','	 J	 ..t.'	 "'r.r)a)o0 c6.4 0 PI	 4.) 0 Fl41) 0 0 H	 Ca 0 .r-1P•	 it 0	 0P4••	 •	 ••• ••rcl	r-1 4-1	 1 4	O	 s=1) 1CI)• •	 ••	 ..	 ..	 ..1-1 0‘43 .1-1 ..--..a)	 $.4	 4-1 0 1-1O g 0	 I	 0 0 1-1k 4-6 C.) 0	 k 0 .1-1p o 0 cr, 	I	 a) o fEj,r2 H0	 r-1 .,-10pa 	 0 1• kP 0-1..	 ..	 ..•r-IPa .---I'2 gOu)Icgral H• Tiz0 ,--I-.. 0 9:10+d.;r--I to0 N .r-1	 P-6 0	 NQ-)1  g	 .#1 -PI 	Ol&I	 .--11..	 ..	 ..	 ..	 ..	 ..N-1:4)%...0Nti•LC-1.4- "v;)	b.)	 N	‘...0	 C.-.)rl	•• •• .• ••	 n 	 • •	 •• ••	 •• 71• 	 ••	 ••	 •.	•n 	 i	 L cri I OIrD 0 .6 4.1	a)	 H	 a)	 kr	 El El	4-5	-P	 -I-) fi	 +1.) ..	 4 '-';' ' g	0	 4.)	 All"	 C:1al	F.. 	 2	 A	Q	 Gads-4	 9 ,-1 0 -1	P.1	 1 C1.1 • CQ 010t	, a)	 a)	II	 - i4	$A)i	 •0 CV •H r-IO "	 a)	 0 • g •	.P	 0 Ei 0	 -P	 FI a) EI 09 d 0	4, fi	 N r.-; 0	 4-)4-) 4-) 0n 0	 d	 cd	 El 0	 d	 0	H L., 0 ;-I 0 fa	 • ri 0 0 k (1) f,r--	 0 La w	 >4 r-	0 	—4•IEI a) fil1 0cin 1-1 .	 p	,-1 PA -,1	 ,	 0 6-- -6-i PA .1- Pi..	 . • . •	E-4 .. E-I..	'..-,	 Ei	 El.. ..P40 0 N n i .r.",  F-1F-i g 1 0 01 0	a)	$.i 0 P.," \ r--1 inI	 4-'	 1	 -1-2 r"--.1 	 C.3za	 PI cl.4	co P4 0 tO 0-1 r---- a)N 04 4-Ir—i	 o -0	 r-i	 o rdcd k	 in	 0	 0 $4	 CO	 0	U 0 k	 0 en 	 C0k00 ‘.-...4--	 ) 40	-,-1 1.. 0	 0nzi k	 -r-1 p.. 0 •	 .	 • 0 'd $-1H0)	 ..-I• +)	 ,...?, 	 A	 1:1 . 40 ...- 	 0 A	A H01 r-I	1	co 0 0	 0), U) -H l'el rl in H pwi 0C r..D	 6,0 p,	 c..) C	 til fa,	-IP	 rd	0:1 up 	 C.) 0 o	 MI Cf)	 lb° 0 0	0 N • 0 0	 0 N • C.) 0	a3 al	 0 H	 0 al	 .4" ri ig	Z '.'s	 1/4..C) . .kJ)..	 ..	 . .	 . .	 . .	 ..•• .	 • •	 .•	 ••	 • •.11 A	 42H a) •H +)	 0 quri0 0 P4	 • (1)03 0	 0 •r4 0X) Pi	 F-6 k 0O CI)A 0)$4O telr.S4 110Cd 0 Ik 0 r-4O 0 tO,0	 -0	 (11.•F9	 ra4)04.,a)0cdO-p00	 •-et4-)cr)O0Pi0Ocd▪0fa4a)C)a)$40a),-0 •4-)0WdH a)OCT\•4-) C04-, 0-P4-)0 Pia) 014• rd•H.4- 0• u)Hc\Irlo• •• ••	 •n • • •	 • •	 • •	 ••   •• •• • ••• •• •• •• ••Mimeo. No. 81416Table 2.--A comparison of the viscosities of liquors A, 3, and C at comparable• degrees of concentration.Liquor samplesA	C:Temper-:Engler :Temper:Engler :Temper-:Englerature	 ature :	 : ature :00. :Number : °C. :Number : 00. :Num ►ber Total solids ....Percent :	 24.9	 25.0	 25.020	 :	 1.29 :	 20	 :	 1.31 :	 20	 :	 1.5190	 .96	 90	 1	 .9g : 90	 :	 .9g	Total solids ....Percent :	 37,5	 :	 35,0	 .	 35:0 .V	 i 		:	 20	 :	 2.12 :	 20	 :	 2.00 :	 20	 :	 2.41	. : .90	 :	 1.10 :	 90	 :	 1.0g :	 90	 :	 1.0g	Total solids ....Percent :	 47.3	 .	 45.0	 :	 43.2	: 20	 : 10.04. 20	 : 5.1g : 20	 : 7.30	: 90	 : 1.39: 90	 : 1.33: 90	 :	 1.41Total solids ....Percent :	 51.0	 50.0	 49.6	: 20	 : 25.90 : 20	 : 15.14 : 20	 : 36.40	90	 : 1.67: 90	 : 1.65: 90	 : 1.90Total solids ....Percent :	 52.3	52.2	 -20	 : 47.70.	 20	 : 25.20 :90	 :	 1.77 :	 90	 :	 1. g2 :        Total Solids ....Percent : 54. g	53.4	 53.940	 : 33. go : 40	 : 15.63 : 4o	 : 33.0o90	 :	 2.77 • 90	 :	 2.32 :	 90	 :	 3.37	Total solids ....Percent :	 57.4	 5s.5	:	 6o	 : 16.94 :	 6o	 : 12.39 :• .3.92	 95	 :	 3.02 :	 :	 ---Total solids ....Percent :	 59.5	 :	 :	 59.76o	 : 40.30 :	 : 6o	 : 29.9096	 :	 4.22 :	 :	 :	 95	 :	 6.ogMimeo. No. R1416Table 3.--Viscosity, temperature, density relationship for sulfate blackliquor available a Labortary'prVor to January 1, 1938.•	 .	 •	Total	 Temperature	 :	 Specific	 'Time of	solids	 :	 gravity :	 efflux for200 cc.•• 	Engler	Percent . :	 00..	. .	 .:	 Seconds	 Number].	 40	 :	 1.0560	 51	 1.02 :. : r-52	 1.0500	 :	 48	 .96.....370	 1.0400	 :	 47	 .9424	 34	 :	 1.1110	 56	 1.1251	 :	 1.1030	 49	 .9870	 :	 1.0935	 48	 .96: 1	 90	 :	 1.0835	 47	 ,9436	 31	 :	 1.1670	 7o	 1.4058	 1.1535	 56	 :	 1.12. 70	 :	 1.1475	 52.5	 :	 1.0590"	 1.1375	 49	 :	 .9848	 •:	 _s3	 1.2180	 276	 5,5258	 1.2055	 109	 2.18	:	 71	 1.1990	 87	 1.7489	 1.1900	 72	 1.466o	 59	 1.2580	 1,120	 :	 22.4071	 1.2520	 653	 :	 13.1090	 1.2430	 272	 :	 5.44Mimeo. No. R1416Table 4.--Evaluation of  data from Babcock and Wilcox Com,mny T s viscosity,temperature charts for  sulfate black liquor.'Total solids	 Temperature	 Saybolt furol	 EnglerPercent	 °C.	 Number	 Number	23.8	 :	 37,8	 9.0	 2.5	23.8	 .	 48.9	 8.o	 2.3	23.8	 6o.o	 7.3	 2.1	23.8	 71,1	 7.0	 2.1	23.8	 82.2	 7.0	 2.1	43.8	 37.8	 20.0	 .2	43.8	 48,9	 16.0	 4.2	43.5	 60.0	 13.0	 3.5	43,8	 71.1	 11.5	 3.1	43.8	 :	 g2.2	 10.0	 2.g	53.8	 :	 65.6	 72.0	 :	 19.0I	 53.8	 :	 71.1	 56.o	 14.5	53.8	 :	 76.7	 43.0	 11.0	53.8	 :	 82.2	 33.0	 8.5	53.8	 93.3	 27.o	 . 7.o	63.8	 .	 52.2	 350.0	 ..	 100.0	63,8	 :	 87.8	 230.0	 60.0	63.8	 :	 93.3	 16o.o	 41.o	63.8	 :	 98.9	 110.0	 PS.0	14.0	 98.9	 6.8	 2.0	23.5	 :	 98.9	 7.0	 2.1	3.8	 :	 98.9	 S.0	 2.3	3.8	 :	 98.9	 9.5	 2.6	53.5	 98.9	 25.0	 6.g	63.8	 98.9	 110.0	 20.01Conversion of Saybolt furol values to Engler values made accordirtI . tochart by H. G. Nevitt, Chem. and Met. Eng. June 23, 1920.Mimeo. /To. R1416Ma EMIMEMIrt,MEM=MUMa,mkrima•MEM'''25 30 35 40 45 50 55 60TOTAL SOLIDS (PERCENT)rco MERC/AL (IASCAA11111111111111111M11nom=nummit,isk,.:Q. ,	 -.:_	 '-/:., ''' P., 61-,r'• C=.44330220/5/035li  ._ ... 	h.	 ......4° . MIMI=ME	 MEMMOMEMEM 	 MEWLIIME MOM MMEMMM„;..,,, kLez„ 74-..., 11	 111Pr ''AINI____ iak.........0:  	i numwrageiiii..35.a X I: .MEMEMOgiI	 I 	 I SAMPLE C	 IEXPERIMENTAL (JACK FINE) SULFATE BLA CK LIQUOR -/0020 30 40 50 60 70 80 90 /00TEMPERATURE (DEGREES CENT/GRADE)FIG. 1VISCOS/ TY-TEMPERATURE-TOTAL SOL/DS RELATIONSHIPFOR. THREE KRAFT BLACK LIQUORSZ M 35152 w

The viscosity-temperature-total solids relationship of sulfate black liquors

https://ir.library.oregonstate.edu/downloads/kk91fq20w

The viscosity-temperature-total solids relationship of sulfate black liquors

Abstract

Similar works

Full text

Available Versions

ScholarsArchive@OSU