July, 1928
4
INDUSTRIAL AND ENGINEERING CHEMISTRY
725
one application, but the mechanical removal of the material have been practiced, however, as no reference has been found by expansion of the growing parts prevented successful con- in the literature on chlorosis. trol for so prolonged a period on young, rapidly developing Application of Marcasite on Sugar Cane plants. However, application of about 8 pounds per acre of Certain small areas of sugar cane on highly calcareous marcasite to the leaves every 2 months has proved a fairly effective means of control in experiments. I n order to dis- soils in Hawaii show chlorosis of the leaves. Spraying of tribute this small quantity of powdered marcasite, it was sugar cane is not very practicable. Application of marmixed with about one-third its weight of infusorial earth. casite to the leaves or in the leaf axils produced a very striking This mixture overcame most of the objections to the handling effect, a perceptible greening being noticeable in less than of marcasite alone. The powdered marcasite itself is some- a week. The treated plants resumed normal growth while what deliquescent and tends to cake on long standing, but the the adjoining untreated rows remained yellow and stunted. mixture can be handled fairly well in a dusting machine. It Alexander and Nichols, a t Ewa Plantation, Hawaii, found an is doubtful, however, if any treatment will replace the spray- extremely pronounced increase in growth curves of chlorotic sugar cane when marcasite was applied. The untreated ing method with pineapples. Recently it has been learned that the treatment for chlo- plants in some cases even died. rosis with iron sulfides as described above has been largely For many plants the marcasite treatment appears the most anticipated by German Patent KO.109,104, granted in 1900 practical method of chlorosis control. A possible fungicidal to Cyprien Chateau. This treatment does not appear to effect of marcasite dust is also worthy of investigation.
Coke Tumbler Tests’ A. R. Powell and D. W. Gould THEKOPPERS COMPANY, CHICAGO, ILL.
ROM the standpoint of the production, distribution, and use of coke, s t r e n g t h and hardness are physical factors of prime importance. All coke is subjected to more or less handling between the ovens where it is manufactured and the blast furnace, cupola, watergas generator, or d o m e s t i c f u r n a c e , where it is used. This causes a degradation in size or the production of exc e s s i v e quantities of coke breeze, which are undesirable from the viewpoint of the user. Various tests have been d e s i g n e d to test coke for strength and hardness, which are the factors that largely determine the so-called handling qualities.
F
Tests for Strength and Hardness
A series of physical tests of coke have been made in a coke tumbler following a design suggested by W. A. Haven, and recently suggested for adoption by the American Society for Testing Materials. Duplicate tests in the coke tumbler give results which are concordant within 1.4 per cent for the stability factor (total per cent on 1 inch), and within 0.8 per cent for the hardness factor (total per cent on inch), the agreement being closer than duplicate results with the standard shatter test. Comparative results are given for twenty-six different cokes as to shatter test, tumbler test, and how these compare with actual plant yields of coke over 2 inches and coke over 1 inch. The stability factor, as determined by the tumbler test, correlates with plant yields of sized coke only as a general trend. The tumbler test does not imitate the type of handling coke receives in the plant as nearly as does the shatter test, but it is indicative of the ability of sized coke to withstand handling between the point of production and the point of use. The hardness factor, as determined by the tumbler test, has little practical significance. The effects due to certain variables, such as duration of test, possible sampling errors, and moisture content of coke, have been evaluated.
Tests for determining the crushing strength of coie have been devised, but the results are so irregular that they are practically worthless.2 Fortunately, coke resists crushing to such an extent that even poor grades will withstand the pressure imposed on it in blast
furnace^.^ Coke is much more liable to breakage by impact while being handled than to breakage by crushing. A standard test has been devised to measure this property-the shatter test.‘ f Presented before the Division of Gas and Fuel Chemistry at the 75th Meeting of the American Chemical Society, St. Louis, Mo., April 16 to 19, 1928. * Proc. Am. Soc. Testing Materials, 16, Pt. 1, 359 (1915). U. S. Geol. Survey, Bull. 886. 4 Am, SOC. Testing Materials, Standards, 1927, Pt. 11. D 141-23.
*
As applied to coke, “hardness” is a term that means the ability to resist abrasion. The method used for testing the resistance of coke to abrasion is the tumbler test. This test also indicates the resistance to impact, a l t h o u g h f r o m a somewhat different standpoint than the shatter test. Some of the limitations of the tumbler test have been pointed out by Kinney and Perrott.5 The Shatter Test
This test is made on a 50pound sample of coke, which consists of pieces which will not in any p o s i t i o n p a s s through a 2-inch square mesh screen. This coke is dropped a distance of 6 feet four times in succession onto a rigidly m o u n t e d steel plate. The percentage of coke remaining on a 2-inch s q u a r e m e s h screen after this treatment is considered to be the significant figure of the test. Generally the coke used for this test is picked from run-ofoven coke or coke which has received a minimum amount of handling before the sample is taken. Such coke has shrinkage cracks which would normally cause breakage b e fore the final sizing a t the plant. Under such conditions, the desired indication of the ability of the finally sized coke to withstand impact is masked somewhat. Another objection to the shatter test is its relative inaccuracy. Kinney and Perrott6state than an accuracy of within 1to 3 per cent is poasible. It has been the present writers’ experience that J. IND. END.CxSM., 14, 926 (1922).
4
Vol. 20, No. 7
1.1 IIUSTRIAL .IND ENGINEBRING CHEMISTRY
726
discrepancies between duplicate aamples may be as high as 5 per cent. The Tumbler Test
Unfortunately, the tumbler test has as yet not been o5cially standasdieed. A large number of modifications exist, but the apparatus used by The Koppers Company Laboratories is based on one designed by W. A. Haven, of the Republic Iron and Steel ComDanv.5 . . A DhotomaDh - . of this machine is shown in Figure 1. The t e t i n a arocedure used. as well BS the design of the coke tumbler; has been submitted to Committee 5-5 of the American Society for Testing Materials. The indications
position. In general, the pieces of coke shsll be sieved out without crushing the larger pieces in order to obtain pieces that will D ~ S Sthe 3-inch and remain on the 2 inch sieve. However, if many of the pieces are larger than 3 inches, i t will be necessary to break out representative smaller pieces of the desired size. This should be done without shattering the coke pieces and can often be done by means of a heavy screw driver by prying apart at fracture cracks. PRocEDuRE-Approximately 22 pounds (10 kg.) of the coke sample which has been previously dried, consisting of pieces which will pass a %inch and remain on a %inch square mesh sieve, shall be weighed and placed in the drum of the tumbler apparatus. The cover shall be rigidly fastened and the drum shall be rotated a t 24 r. p. m. for a total of 1400 revolutions. All of the coke is then removed from the drum and sieved, using the following square mesh sieves: 2-inch, l.5-inch. 1.050-inch, 0.525inch. and 0.2153-inch. Far coke larger than 2 inches, each piece shall be up-ended to determine whether i t passes through the 2-inch sieve in any position, while for coke smaller than 2 inches the coke sl1all be shaken rather vigorously in order t o up-end the pieces until vracticallv no mare coke will nass throigh the openings. The coke &mining on each s’reve and that which passes through shall be weighed separately. The entire sieve analysis after the tumbler test shall be reported as cumulative per cent to one decimal as follows:
__
Per /mi, T o t a l rctoiord on 2 inches
____ (EUbiIitY facror)
Totd retained on 1.5 inches Total retained OII 1.080 inches’ Total rrtdned on 0.323 inchR ‘htrl retained 0x1 0.263 io&* Quantity passing through 0.283 inchD 7-otri
........................
Fiaure I-Coke
Tumbler
are that the method will be adopted as a standard. This proposed A. S. T. M. tentative method for tumbler test of coke is as follows: APPARATUS-...-TUlllbll.I Mackichine. The tumbler machine shall consist of a steel drum of a t least 0.25-inch plate, 36 inches inside diameter, and 18 inches inside length. Two equally spaced 2 by 2 by 0.25 inch angles are to be riveted longitudinally inside the drum. These angles are to be sa riveted to the shell that the attached leg points away from the direction of rotation, thus giving a clear unobstructed shelf for lifting the coke. The drum is t o be mounted on a horizontal shaft and rotated a t 24 I. p. m. (tolerance i l 1. p. m.). An opening should be provided. preferably in the shell, for introducing and removing the sample. Diiring the test the cover shall be rigidly fastened to the sliell and shall be so constructed as to fit into tlrc shell in order to have a smooth inner surface. Sicscs. For sizing the sample for t a t , square mesh sievcs having 2- and 3-in& actual openings between the wires shall be used. For sieving the coke after the tumbler test, square mesh sievcs having %inch, 1.5-inch, 1.050-inch, 0.525-inch and 0.263inch actual opening between the wires shall be used. Sieves of heavv duuhle crimmd wire about 24 inches in diameter are satisfactory. SAMPLING-TII~ sample of coke collected slid1 be of sufficient quantity to obtain approximately 25 pounds of coke pieces which will DBSS a %inch and remain on a 2 inch souare mesh sieve. This is best accomplished by placing a container or scoop in the coke stream and eollecting small increments at regular intervals so as to represent the entire quantity of coke under considcration. In sizing the sample for test each piece of coke shall be “upended”-that is, tested to see if it will pass the screen in any ~~
~~
*Yearboak el American Iron and Steel Institute. 1928. P. 171.
1.0. 0.5, and 0.29 inch.
___
(hardness l‘acfoiJ
~
........,
** I’or convenirilce, these sizes WIIIbe reirrred
ai
-__
100.0per cent i n this report
to herealter
Names have been assigned t o two values in the sicve analysis after the tumbler test, as indicated in the report of the sieve analysis. The tumbler causes the coke to undergo a combination of dropping and rubbing. To facilitate this, angle irons are set on the inside of the periphery of the drum. The destructive action is much less for each blow the coke receives in the tumbler as compared with a single drop of the coke in a shatter test, but it is repeated many times. The abrading action of the coke lumps colliding with other lumps and against the walls of the tumbler machine more nearly approximates the forces of attrition to which a coke is subject in handling and in piling. Each tumbler test furnishes two significant figures. which have been chosen more or less arbitrarily. The first is the “stability factor,” which is the percentage of the original coke weight remaining on the 1-inch sieve. This is intended t o serve as a measure of the ability of the coke t o resist breaking up into small pieces. The other is the “hardness lactor,” which is the total percentage of the original coke weight remaining on the 0.25-inch sicvc. This is intended as a measure of the ability of the coke to resist abrasion, with consequent production of breeze and dust. Comparison of T u m b l e r Tests, Shatter Tests, and Plant Coke Yields
Figure 2 gives a graphic comparison between the results of tumbler tests, shatter tests, and actual yields of coke over certain sises as obtained from full-scale coke-oven tests. The data together with the entire screen analyses of the cokes after tumbler test are also shown in Table I. Each of the twenty-six cokes w&s made from an entirely different coal mix, so that these results do not represent simply routine daily plant pract.ice. These cokes represent a gradation in physical coke quality from poor up to the highest grade. The plant yield of coke orer 2-inch represents the percentage of the total coke which would remain on a 2-inch screen, after undergoing the usual handling in the plant. For convenience, the cokes have been arranged in order depending on these figures. The plant yield on 1-inch is the percentage of the total coke on a 1-incl: screen. ‘The general trend of both the shatter test and the stability factor curves is in the same direction as the plant yields of sined coke, and this was the general result to be expected. Ilon-ever, both of these curves are decidedly irregular. Since
INDUSTRIAL AND ENGINEERING CHEMISTRY
July, 1928
Table I-Data
I
for Cokes Used in T u m b l e r T e s t s
COALCHARV,M, Pulverization through 1/a in.
8i:d (
1 2 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 2s
HATTER
TUMBLER TEST(CUMULATIVE)
ACTERISTICS
COALMIXTURE
COKE
727
On 2 in.
On !.5 in.
On 1 in.
On 0.5 In.
On 0,25 in.
TEST
Througl 0;25 in.
On 2 in.
PLANT YIELDS
On 2 in.
On 1 in.
%
70
%
75
%
%
%
70
%
%
%
31.0 32.6 29.6 28.4 27.9 28.6 33.7 30.9 30.7 29.4 30.6 29.0 29.5 34.4 31.4 29.9 29.5 30.9 28.3 31.3 27.5 29.0 28.2 28.6 25.5 25.8
66.3 78.7 81.0 86.0 86.0 84.7 84.7 83.3 82.3 81.3 81.7 81.7 81.4 79.0 80.0 81.0 80.3 78.3 80.4 78.0 77.0 77.2 76.0 73.6 80.3 51 5
0.0
9.1 10.0 17.7 15.9 15.0 15.0 5.9 11.0 11.4 15.0 15.9 10.0 17.3 14.5 28.1 15.9 14.6 16.6 31.9 19.1 32.2 30.0 28.8 15.9 25.2 28.7
41.8 36.5 47.3 50.9 46.4 42.7 35.5 44.2 45.5 42.7 43.2 40.9 44.2 44.1 53.6 48.6 45.5 45.5 58.3 43.2 59.5 57.3 55.2 50.0 50.2 54.2
62.7 60.5 65.5 68.2 68.3 62.7 64.6 65.6 66.0 62.7 64.5 65.9 61.5 64.1 64.9 64.8 63.2 66.1 68.3 61.4 67.7 66.8 65.6 59.1 60.5 62.8
69.1 65.5 68.2 70.0 70.6 65.4 69.6 68.8 69.6 65.4 67.2 68.6 67.4 69.5 67.2 67.1 67.7 70.0 70.1 65.0 70.0 68.2 66.9 66.8 62.0 64.2
30.9 34.5 31.8 30.0 29.4 34.6 30.4 31.2 30.4 34.6 32.8 31.4 32.6 30.5 32.8 32.9 32.3 30.0 29.9 35.0 30.0 31.8 33.1 33.2 38.0 35,s
62.8 59.8 67.4 66.4 71.8 75.6 56.3 66.6 65.2 70.5 66.4 70.8 69.3 58.7 65.0 73.4 63.6 58.4 76.4 66.1 73.5 74.8 73.2 66.5 71.1 64.6
65.2 65.5 67.3 70.1 65.6 76.2 53.4 67.9 63.3 74.5 72.5 69.7 68.0 68.9 75.8 71.7 71.1 67.7 77.6 72.4 77.4 76.0 78.4 76.0 72.1 66.5
91.2 90.1 91.6 93.2 90.2 92.9 88.4 92.2 91.1 93.5 92.8 92.8 92.4 90.7 93.5 92.7 92.0 92.5 93.8 92.5 94.2 92.7 95.3 94.2 93.6 91.1
0.0 3.6 1.4 2.3 2.7 0.0 1.4 0.0 2.7 0.0 0.0 0.0 0.0 0.0 2.3 0.0
0.0
1.0 0.0 4.5 4.1 5.6 0.0 0.0 1 4
The low volatile (L.V.) coal in all mixtures was from West Virginia
the shatter test imitates more or less the handling which the coke receives while in the plant, it should to some extent indicate the yield of sized coke which might be expected. The irregularity is due, in some measure a t least, to the inaccuracy of the shatter test. In the case of the stability factor, as determined by the tumbler test, the irregularities cannot be explained in this manner. The limit of accuracy of the tumbler test was determined by making sixteen tests in duplicate. The following gives the mean deviation between duplicate tests : Screen size, inches 2.0 Mean deviation between duplicates, per cent 1.1
1.5
1.0
0 5
2.3
1.4
1 0
0 . 2 8 -0 25 0.8
0 5
Maximum variations are slightly higher than these figures but when tumbler tests are made i n d u p l i c a t e by the s a m e o p e r a t o r the average can be expected to be concordant within 1.4 per c e n t f o r t h e s t a b i l i t y factor and within 0.8 per cent for the hardness factor. Inaccuracies in t h e test method, therefore, will not e x p l a i n t h e i r r e g u l a r i t i e s shown. As a matter of fact, the tumbler test does not imitate very closely the type of handling that c o k e r e c e i v e s in the w/"
to an exaggerated degree. the degradation to which sized coke is subjected after it is properly screened and during the various handlings which it undergoes to the point of use. The stability factor curve shows that this physical property of coke cannot be definitely predicted, either from the shatter test or from the percentage yield of sized coke a t the plant. ZS%SOF COTE
PLANT
Figure 2
WELDS
Both Haven6 and Kinney and Perrottj have pointed out the relative inaccuracy of the hardness factor. For instance, a coke might shatter badly a t first, and the smaller pieces then would not be subject to the abrasive action that coke in large pieces would. In these tests the hardness factor is quite variable and follows no definite trend. The writers agree with the previous investigators that the hardness factor is of much less significance than the stability factor. Effect of Duration of Tumbler Test
Although 1400 revolutions of the tumbler drum has been arbitrarily chosen as the duration of the test, a series of tests was made of the same coke run for 350, 700, 1050, and 1400 revolutions. The results are shown in Figure 3. Although the results, as shown by screen test, are somewhat out of line a t 350 revolutions, the results a t 700 revolutions are of
Figure 3
the same relative character as a t 1400 revolutions. This suggests that the test might possibly be shortened somewhat. Effect of Certain Errors on Tumbler Test
The collection of strictly representatire samples of coke is of even greater importance for tumbler tests than for chemical analysis. To show this, coke samples were collected from three different parts of the same oven-the pusher end, the middle, and the coke end. The cumulative percentages of each size after the tumbler test follow:
INDUSTRIAL A N D ENGINEERING CHEMISTRY
728 Screen size, inches Pusher end, cumulative per cent Middle cumulative per cent Coke eAd, cumulative per cent
2.0 3.6 3.1 2.8
1.5 26.3 21.3 17.3
1.0
55.7 50.7 47.8
0.5 67.2 66.7 64.5
0.26 69.2 68.9 67.2
I n this case the stability factor varies 8 per cent between samples of coke from the same oven. Since the preliminary drying of the coke is an extra step in the procedure, some tests were made to determine the necessity of this. A typical test between coke with a moisture content of 9.5 per cent and the same coke subjected to the usual preliminary drying gave the following results : Screen size, inches Coke dry, cumulative per cent Coke: wet, cumulative per cent
2.0 3.9 6.8
1.5
1.0
0.5
0.25
52.0 65.6 68.2 57.0 75.1 7 8 . 1 Although the wet coke in this case has a moisture content considerably above normal, it indicates the necessity of drying all coke before it is submitted to the tumbler test. The effect of tumbling coke which has not been given preliminary #dryingis to cause abrasion of fine material which clings to $he larger pieces and cushions their fall. 24.3
19.9
Practical Value of Tumbler Test Judging by the results obtained from a great many tests, it is believed that the stability factor, as determined by the
Vol. 20, No. 7
tumbler test, has considerable value as an indicator of the extent to which size degradation will occur in the handling of coke. Unfortunately, it is impossible to give a quantitative comparison between tumbler test results and the actual degradation results occurring between point of production and point of use. I n the handling and transportation of coke, it is subjected to so many variables that it would be useless to try to compare such practice with the results from the closely controlled conditions of the tumbler test. However, there are many indications that tumbler test results correlate with actual practice. For instance, it is well known that the handling qualities of coke are usually greatly improved by the addition of low volatile (semi-bituminous) coal to the high volatile coal used in making the coke. I n several cases it has been possible to study series of cokes, ranging from that made from 100 per cent high-volatile coal, to that made with 30 per cent low-volatile coal in the mix. In such cases the addition of a small percentage of lowvolatile coal causes a decided increase in the stability factor of the coke, and each addition of low-volatile coal further increases the stability factor, but a t a decreasing rate. This corresponds to facts that are well known in coke technology.
Physical Properties of o-Dichlorobenzene' T. S. Carswell MONSANTO CHEMICAL
HE data for common organic compounds given in the literature often show marked discrepancies, particularly in the case of compounds which may contain as impurities isomers of very similar properties. o-Dichlorobenzene is an excellent example of such a compound, because the para and mpta isomers are so closely related in physical and chemical properties that it is practically impossible to prepare pure ortho from a mixkure of the isomers. Other authors have overcome this difficulty by synthesizing the o-dichlorobenzene in such a way that no other isomers can be formed. However, even then great care must be taken to use purified reagents throughout the synthesis, in order to avoid contamination of the product.
T
Schmidt and Ladner2 heated o-bromonitrobenzene with ammonium chloride, and obtained o-dichlorobenzene, boiling a t 179" to 180" C. under 755 mm. Holleman3 reduced o-nitrochlorobenzene, of crystallizing point 29.0' C., with tin and acid to o-chloroaniline, and fractionated the latter. The fraction boiling below 225" C. was purified by crystallization of the picrate and the purified o-chloroaniline was transformed to o-chlorobenzene through the diazonium compound. The product boiled a t 178" C. under, 762.5 mm., and a t 86" C. under 18 mm., and had a specific gravity a t 19.1" C. of 1.3039. Holleman and Van der Linden4 reduced o-nitrochlorobenzene, the purity of which is not stated, with iron and acid to o-chloroaniline, diazotized the hydrochloride of the latter, and added the diazonium chloride to boiling cuprous chloride. The product was steamdistilled and redistilled under vacuum and atmospheric pressure, after which it boiled a t 179' C. under atmospheric pressure, at 65.8" C. under 14 mm., and had crystallizing point -17.6" C., n: 1.5532, and specific gravity 1.3039 a t 19.1' C. Narbutt5 fractionated o-CsHaC12 from Kahlbaum twice a t 49 mm.; the product was partially crystallized and the liquid drained off. The crystals then had crystallizing point -17.5" C., n: 1.5524, Presented before the Division of Dye Chemistry a t the 75th Meeting of the American Chemical Society, St. Louis, Mo., April 16 to 19, 1928. 2 Ber., 37, 4402 (1904). 3 Rec. trav. chim., 23, 358 (1904). 4 Ibid., 90, 305 (1911). 5 Ber., 62B, 1028 (1919).
WORXS, S T .
LOUIS,MO.
1.3104, and dno 1.3048. The International Critical Tables (1926) give for o-CBH4C11 a melting point of -17.6" C., boiling point 179" C., density 1.298, and TZ? 1.549. dla
The writer followed essentially the same method as that of Holleman, with certain modifications. The o-nitrochlorobenzene used to start with had a crystallizing point of 32" C. This was reduced in the usual way with iron and hydrochloric acid. Reduction with iron is better than with tin, since chlorinated by-products are liable to be formed with the tin. The chloroaniline was fractionated in vacuum, and the distillate was dissolved in hot, dilute hydrochloric acid. On cooling, crystals of the hydrochloride separated, and were filtered off and washed. The purified hydrochloride was diazotized, and was added at 0" C. to a solution of cuprous chloride in hydrochloric acid. Decomposition in the cold rather than at the boiling temperature minimizes the chance of by-product formation. The decomposition was complete in a few minutes at 0-10" C., and the product was removed by steam distillation. The oil was washed with dilute sodium hydroxide to remove any phenols, and the washed oil was fractionated first under vacuum and then under atmospheric pressure. The product so obtained had the following properties: Density Crystallizing 18°/150 point, C. C. Density' 20°/200 C. Boiling boint, 757.4 mm., Boiling point, 745.2 mm., Refractive index,
%?
0
c.
c.
-16.7 1.3112 1.3088 180.2 179.5 1.5818
From the two boiling-point readings, the barometric correction for the boiling point at atmospheric pressure is 0.058" C. per millimeter. Applying this correction, the boiling point at 760 mm. is 180.3' C. All temperatures were taken with thermometers standardized by the Bureau of Standards. The densities were taken in a bottle-type pycnometer, and the refractive index was determined with an Abbe type refractometer.
