T H E J O U R N A L O F I , V D C S T R I A L A-VD ENGIAVEERI,VG C H E M I S T R Y
516
TABLEI ORIFICE ACTUAL HEAD Diam. READING TEMPERATURES A 5 READ(b) R u n Inches(a) Inches Volts Amperes TI Ta T3 T4 T6 ” 6 1 0 0 68 8 5.22 14 327 675 673 14 2 0.083 3/32 68 5.0 7 348 656 586 7 3 0 0 72 10 345 i l l / 1 1 5.5 10 4 0 . 18 3/32 73 6 378 680 591 5.4 6 5 0.08 3/32 72 6 376 693 616 5.4 6 0 0 i3 11 349 719 718 5.5 0.035 3/32 73 7 378 708 650 5.4 0.035 3/32 63 7 311 586 535 4.75 9 0 0 63 4.75 14 293 596 592 10 0.085 3/32 63 7 315 576 507 4.8 11 0.18 3/32 62 6 297 530 455 4.7 12 0 0 4.38 10 257 528 522 13 0.180 3/32 4.38 7 262 465 401 14 56 1.0 4.38 I 210 322 257 1/4 15 0 0 49 3.75 15 208 420 416 15 1/4 1.18 3.75 6 161 247 190 48 7 0 0 3.75 49 205 412 410 12 ‘ 2 160 238 187 18 0.3 47 3.75 ;/8 7 19 60 0 4.7s 13 284 563 564 13 20 0.6 3/8 :5 21 0.6 ... .-. 22 0.6 8s 8 376 546 ,is 6.38 iii 8 23 3/8 0.6 6.9 91.5 11 444 644 517 276 11 24 3/8 0 3 95 11 480 718 599 316 11 6.95 25 0.75 60 5.0 10 139 146 112 92 10 3/8 26 0.75 53 4.42 19 122 127 98 82 19 3/8 2i 0.75 68 5.5 22 I 7 7 188 142 120 22 3/8 96 28 0.75 .~ 7.5 I5 306 347 255 201 15 3/8 29 0.83 59 13 117 120 5.0 91 90 13 1/2 30 70 5.75 12 148 151 116 114 12 0.83 1/2 31 99 0.83 7.9 15 260 270 214 196 15 32 86.5 12 212 216 160 I59 12 0.83 6.95 1/2 33 0.15 85 6.75 13 279 317 242 188 13 112 34 13 144 159 118 102 13 57.5 0.15 4.i5 35 1/2 103 0.15 7.95 13 3;; 424 309 253 13 36 0 21 0 1.88 14 104 104 55 14 3; 0 35.5 I5 124 236 236 122 15 2.83 0 ( a ) Runs 1 to 24 in inches of Liquid; Runs 25 to 37 in in ches of Mercury. ( b ) Tz t o Ts, a s read b y thermal-couples; T i and T6,temperatures of water b a t h a t opposite ends of the furnace.
6
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k
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hv. Temp. of Furnace 111 161 211 26 1 311 361
Input Net Watts 253 380 523 662 804 925
TABLE111. Temp. Exit Gas 80.7 108.7 140,O 171.0 202.0 229 . 0
Vol. 8 . No. 6
Average Temp. Value Difference of “ K ” 53.3 3.84 87.5 3.52 119.0 3.56 151.0 3.54 183.0 3.56 218.0 3.44
of this film, t h e shearing eEect upon this film should be determined b y t h e mass of gas passing t h e heating. surface in unit time rather t h a n b y its linear velocity, and t h e use of t h e above unit of velocity is rational. The constancy of t h e results of our calculations by this method are, however, its best justification. TTe believe t h a t t h e above equation represents the best figure which is a t present available t o employ
ti;
through each square foot of section, t h e section being taken a t right angles * t o both heating surface and direction of flow of the air. The expression is apparently independent of temperature u p t o 7 j o o F. I n t h e derivation of this formula we have expressed velocities as lbs. of air per sq. f t . of section of p a t h per second. Our reason is t h a t otherwise velocity past various points in the p a t h of flow is a variable TABLEI1 Group Run A1 . . . . . . . . . A*. . . . . . . .
BI. . . . . . . . .
E*. . . . . . . . .
2 10 5 29 30 31 32 20 21
22 23 CI . . . . . . . . . 25 26 27 28 C2 . . . . . . . . . 1 8 24 Di . .’ DZ. . . . . . . . . 4 11 13 Blanks.....
Area Av. Ht. Av. Temp. --CORRECTED-Sq. in. In. ‘ C. Volts Amperes WATTS 2.43 83.3 I , 16 55.5 3.24 101.3 37.48 4.99 66.0 4.87 4.37 61.5 4.65 32.80 5.30 70.0 5 28 39.75 6.64 57.3 8.71 68.0 16.07 97.3 84,) 12.67 17.65 2.35 235 59.0 4.60 271 5.40 3j8 24.00 3.20 320
39g 481 111 Xi3 134 258 173 549
58,0 51.0 66.0 94.3 45.0 93.3
:ii
2;:; i::::zi
38.79 29.84 26.07
5.17 3.98 3.48
517 398 348
71.0 60.0 55.0
5.28 4.55 4.23
43.59 35,4j 31.58 24.78 24.46 33.95 5.41 14.3i
5.81 4,j3 4.21 3.31 3.26 4.53 0.72 1.91
z;:;
2;4:.;2 3 ii: 233
i2 :::ti 6
12 15 ii 19 36 37
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4.8 3 91 9 1.11 8.73 1.3-1 2.58 1.13 5.49
2 96 . 9025 3 8.33 6.55 10.05 19.38 12.96 41.19
::::: 2:;
;;581 2 li3 421 331 326 423 ‘2 191
4.87 4.30 5.40 7.42 3.55 6.85
282 218 356 700 160 639 375 273 233
2:;
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18.9
3.54 3.55 4.60 1.65
166 167 267 31
33.5
2.63
88
65.0 47.5 47.0 58.0
quantity om-ing t o t h e expansion of t h e gas in heating. On t h e assumption t h a t t h e resistance t o flow of heat from a solid t o air is due t o a surface film of gas around t h e solid and t h a t t h e increase in heat conductivity with increasing velocity is caused b y t h e ripping off
1
402
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8
,
d54
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I d56
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,058
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for t h e value of K from solids t o air and feel t h a t i t is decidedly preferable t o t h e figure of Richards, t h e one hitherto most frequently employed, because Richards’ formula indicates indefinitely high values at high velocities. whereas our formula indicates, as the experimental results shov-, t h a t a t high velocities the value of K reaches a limiting value beyond which it cannot rise. RESEARCHLABORATORY O F PLIED CHEMISTRY MASSACHUSETTS IKSTITUTE OF TECHXOLOGY
LABORATORY PROBLEMS IN INDUSTRIAL CHEMISTRY By H. K. BGKSON Received March 23, 1916
The field of industrial chemistry is so large t h a t t h e Dlanning of courses in this subject involves many factors. I t has been t h e experience of t h e writer t h a t instructors in industrial chemistry formulate their courses largely from the standpoint of their previous personal experience. I t is believed t h a t a n exchange of views detailing t h e practice followed b y various instructors would prove of great value t o individuals as well as be an aid in standardizing the subject matter and in working towards some degree of uniformity. With this end in view a series of problems are here outlined showing the character of training furnished b y such problems. Such a course is not t o be regarded as ideal b u t rather is proposed as an aid t o a discussion t h a t might be of value t o those who are feeling their m-ay along paths t h a t are not as yet well defined. The problems were assigned t o chemistry students of Junior standing. They had completed courses in general inorganic chemistry, qualitative analysis, quantitative analysis, and were taking organic chemistry coincident with industrial chemistry. The general plan followed was the statement of t h e problem by
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June, 1916
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
t h e instructor after which t h e student was expected t o devise his own methods for solution. T h e instructor answered specific questions b u t refused t o suggest an outline or general plan of procedure, requiring t h e student t o work out his own methods from t h e literat u r e . A full discussion a n d exchange of methods among t h e students in t h e laboratory was, however, encouraged. Experience has shown t h a t students a t t a c k such problems in a wide variety of ways a n d frequently with varying results. These are criticized a n d amended in class discussions a t t h e end of each semester. PROBLEM given a sample of crude California petroleum, obtain t h e yield of kerosene oil which complies with t h e requirements of t h e s t a t e law. Requiijements: An examination of t h e s t a t e law, reference t o t h e literature of petroleum refining a n d familiarity of the student with t h e varying effects of t h e r a t e of distillation, t h e design of distilling apparatus, t h e effects of acid a n d alkali t r e a t m e n t , t h e removal of water from oily distillates, a n d t h e various forms of oil testing apparatus. P R O B L E M 11-Given a sample of coal-gas t a r a t a local cost of 6 cents per gallon. determine t h e yield of creosote complying with t h e specifications of the city of Seattle 2nd t h e cost per gallon. f . 0. b. plant, of t h e creosote. Requirements: The specifications of t h e city for creosote, t h e distillation of t h e coal t a r . computation of fractions a n d t h e derivation of the process of distillation, t h e analysis of t h e creosote by t h e official method. a s t u d y of t h e uses a n d values of t h e by-products such as light oil 2nd pitch, t h e selection of a unit charge for commercial operation, a field s t u d y of a Barrett plant, a n d itemization of costs of production. P R O B L E M 111-Prepare a bituminous enamel containing 2 0 - 3 j per cent carbonaceous matter insoluble a n d j j-6 j per cent ash. with physical properties specified by t h e United States War Department. Requirements: A study. of t h e commercial pitches, methods of analysis of bituminous materials a n d selection of a paint filler. P R O B L E ~ Z I Iv-Determine which one of two commercial boiler compounds shall be selected t o prevent scale formation in t h e University Power Station. Requirements: Analysis of scale, of feed water a n d of t h e boiler compounds; a s t u d y of t h e causes a n d prevention of scale formation a n d t h e application of t h e d a t a t o t h e given case. A description of t h e problem has already been published in THIS J O U R X A L , 8 (19161, 435. P R O B L E X v-Determine t h e effect of blending Portland cement with Washington tufa. Requirements: Reference t o t h e literature of blended cement products; testing of cement b y standard methods; a n d a s t u d y of cement specifications. P R O B L E X v-Determine t h e proportion of cement, sand a n d gravel in concrete. Requirements: Method of mechanical analysis; grading of aggregate; specific gravity determinations; chemical analysis of cement; 2nd computations.
517
P R O B L E X vII-Determine t h e effect of a d d i n g lime a n d sand t o a plastic red burning clay. Requirements: Methods of clay testing; s t u d y of range of vitrification; grinding a n d mixing operations. P R O B L E M vm-Classify t h e oil obtained from samples of Philippine nuts. Requirements: Extraction of oil from n u t s ; comparison with t h e known constants of f a t t y oils; a n d t h e relation of constants t o uses of t h e oil. P R O B L E M Ix-Determine t h e yield of rosin in western yellow pine. Requirements: Methods of sampling; extraction b y various solvents; a n d efficiency of commercial solvents. P R O B L E M x-Determine t h e efficiency of t h e recovery of ammonia in t h e extraction of rosin from Douglas fir. Requirements: Separation of rosin a n d humus; Kjeldahl determinations; removal of ammonia from wood; a n d computations. P R O B L E M XI-Devise a method for t h e extraction of cedar oil from t h e destructive distillation of P o r t Orford cedar and determine t h e nature a n d probable uses of t h e residues of t h e distillate. Requirements: Methods of d a m distillation a n d of vacuum distillation; s t u d y of literature relating t o Port Orford cedar oil; determination of constants of oil; s t u d y of mood t a r s a n d their uses. P R O B L E M xII-Prepare a rosin paint drier soluble in raw linseed oil. Requirements: Preparation of metallic resinates; methods of paint testing; a n d cbmmercial requirements of driers. During t h e present year similar problems dealing with t h e s t u d y of cactus, wood humus, potash salts, recovery of iodine, cost of manufacture of hypochlorites, etc., have been undertaken. I t is apparent t h a t t h e problems are capable of great diversification, which adds t o t h e interest. T h e chief objects in view are t o throw t h e student upon his own resources, make him acquainted with chemical literature a n d force him t o make use of t h e tools of knowledge already in his possession. LABORATORY OF INDUSTRI 4~ CHEMISTRY OF WASHIRGTON, SEATTLE UNIVERSITY
AN UNUSUAL EXPLOSION IN CONNECTION WITH POTASSIUM CHLORATE By FLOYD E ROWLAND
Received May 3 , 1916
There was nothing unusual about t h e explosion itself, b u t t h e manner in which it occurred is well worth mentioning 2nd bringing t o t h e attention of all who ha1-e occasion t o use pestles which have wooden handles. Everyone knows t h a t disaster is sure t o follow when potassium chlorate a n d sulfur are ground together; b u t t o have 2 perfectly clean mortar a n d pestle suddenly explode with great violence, when one is grinding a n inert substance like pumice stone, makes one pause a n d wonder why. A pestle a n d a n 8-inch mortar were thoroughly cleaned a n d about fifteen pounds of potassium chlorate were ground with no disastrous results. The mortar
