TEIE J O U R N A L O F 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
844
1914
1918
1920
Imports Collodion, and manufactures of, value. $569,763 $53,637 Explosives : Fulminates, gunpowder, etc., value.. $256 379 97,860,139 $437 010 All other value.. $600’958 Glass and ilassware, value.. $8 191’833 $1,723:014 Glue and glue size, lbs.. 22:714:877 2 048 543 $3:856:961 Matches, value.. $882,812 Oilcloth for 0oors: 3,724,086 38,584 Linoleum, sq. yds.. 340,288 5,060 Oilcloth, sq. yds.. $961,047 Paints, pigments, etc., value.. $2,325,222 PaDer and D U ~ D : Printing paprr NotoverSc.perlb., l b s . . 536,815,2881 1,203,762,1181 All other, lbs 6,053,429 278,367 6,925,505 380,153 Surface-coated paper, lbs.. 36,515,554 6,150,942 Wrapping paper, lbs.. Wood pulp Mechanical tons.. 177,484 189,599 296,465 Chemical, &bleached, tons 302,963 18,044 Chemical, bleached, tons... 88,917 Photographic goods: $33,857 Drv d a t e s . value.. (z) .. M-&Con-picture films 47 462 715 Not exposed lin. f t . . 44 717 3238 $713:363 Negatives, lih. f t .......... $402:7044 $3 374 497 Positives, lin. f t . , , , , , . , , $20 057 144 $2033719 Other films and plates, value $3243535 Soap: Castile lbs.. 4 622 082 1 016 399 All oth)er, value.. .......... $4601485 $2113149 Sugar and molasses: Molasses, gals,. 51,410,271 130,730,861 Sugar 750 2 367 708 Beet, lbs.. Cane, lbs.. 5,061),564’,621 4,898,277,025
..................
$82,940
................. .......... ... ....... .............
$2,369,250 $765 412 $3,582:377 1 4 1 0 104 $1 :096:982
......... ..........
..
.............. .. ...... .......
522,999 62,372 $1,975,769 1,322 890 825 1:371:576 4,dSi,i 17 194,119 442,844 89,587
.........
$25,808
.....
.
46,485,434 $1 417 774 $3’327’566 $1:355:832
...............
2 352 974 $192: 103
............
154,670,200
...............
1,219,834 7,590,911,767
..............
Exports Baking powder lbs.. . . . . . . . . . 2 725 964 Blacking and pblishes, value., $6491395 Candles, lbs.. 3,047,756 Celluloid and manufactures, value.. . . . . . . . . . . . . . . . . . $1 387 541 Chewing gum. value.. $1781630 ExplosiGes : Cartridges, loaded, value.. $3,521,533 14,464,601 Dynamite, lbs.. (2) Fuses, value. 989,385 Gunpowder, lbs..
................
.
6 046 455 $1:009:100 6,761,767
5 595 126 $2:845:110 7,691,420
........
$3 744 745 $1:896:135
$10 044 242 $2:617:483
.. ............ .............. ...........
$13,672,371 18 911 668 $19:346:554 340,516,883
$9,729,937 12 566 057 $709:662 1,721,991
a t not above 5 cents a Dound prior t o April 24, 1920. N o t stated separately. From Oct. 3, 1913, t o June 30, .1914. Stated as “All other” motion-picture films in 1914.
1 Valued 9 8 4
12,
No. 9
TRADE IN MISCELLANEOUS PRODUCTS (Concluded)
TRADE IN MISCELLANEOUS PRODUCTS ARTICLES
Vol.
ARTICLES
1914
1918
1920
Exports Explosives (Continued): Shells and projectiles, loaded, value. All other, value. Flavorinz extracts and fruit juices, value. Glass and glassware, value.. Glucose and grape sugar: Glucose, lbs.. Grape sugar, lbs., Glue lbs.. .................... Indii-rubber manufactures, value.. Ink: Printers’, value.. All other, value.. Matches, value. Metal polish, value.. Mucilage and paste, value., Oilcloth: For floors sq. yds.. ......... All other,’value. Paints, pigments, etc.: Dry colors Carbon bone and lampblack’ value). All qther, ’value.. Lead Red, lbs.. White,.lbs.. Ready-mixed paints, gal. Varnish, g a l . , Zinc oxide, lbs., All other. value.. Paper and pulp: Newsprint, lbs.. Other qrinting paper, lbs.. . . Wrappmg paper lbs.. Writing paper add envelopes, value.. Wood D U ~ D .tons.. Photozrabhk’eoods: Mo&o
................................. co.................................... ..................................... N, .....................................
5.0
9.2
6.5
17.1
10.3
20.13 2s. 0
21.6 28.6 32.5
30.0
36.U
18.2 21.6 24.8
10.0
1s.v
14.i
mater necessary decreases with an increase of the total gas pressure. However, thc energy reqjiiired for pumping this decreased water at the increased pressnre is not greatly altered. A t a given total gas pressure. the quantity of solvent water necessary is not greatly affected by variations in C O , concentrations, since as the CO, t o be dissolved decreascs, the solubility also decreases. Hence, CO? absorption should be completed in one stage rather than in a series of s t a p e s at decreasine concentrations.
2- 4 52- 52 17- 17
H,
-
TOTAL,100-100
x ( C I L , argon. etc.) C O O L I N G G,\S AND CO
The converted gas iss still at a somewhat elevated temperature, I t is cooled and the excess steam condcnsed in special condensers. The composition of the gas mixture issuing from the condensers is then as given in t h e preceding paragraph . Ill-PURIFICATION COMPRESSION
OF
GAS
AND
OF G A S REXOVAL
OF
CARBON
UroxIDE-The chief impurity in the gas at this stage is carbon dioxide, which is removed by scrubbing the gas mixture with water a t high pressnres.'~6,10 T h e dry gas is compressed in a multi-stage compressor up to the pressure at which it is to remain through the rest of the process, or perlraps t o some intermediate pressure. The optimum pressure ?vi11 depend on local operating conditions. For remora1 of the carbon dioxide the compressed gas is passed upward in a scrubber tower, countercurrent t o \rater flowing downward over suitable packing. The composition of t h e washed gas a t thc exit of t h e scrubber is given in Table 1.1. If desired the residual carbon dioxide (0.1 t o LO per cc,nti remaining after water scrubbing lay ii:islrin~tlie gas m-ith n cold caustic solutio:^.:'
ai; 4 - - I h u r ~ m W,nrsn
S c x i m i i ~ nToweu Siivwma Oriiea A i i i i n n i ~ i i s AN!, MAZE OF P I P ~ G
The scrubbing water with its dissolved carbon dioxide (and hydrogen sulfide). as ivell as sonic hydrogen and nitrogen. passes from the bottom d thc srrubiiing tower and discharges through a vat,ter \x-lieel." Here the dissolve,d g:;ise,s are liheratcii a n d nijiicli of t h e power TABLE V I I I - ~ O X ~ ~ Sor ~T Drs5o~viiu ~ ~ ~ N Grs
Per cent
..............
Rn?z.b
WnTilii
1'l.i cciit
i o...................................
>I?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Ir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . s !ll:S, cmi, erc.) ......................
ifj-
ni
1:-
11
4-
4
1
n r ~ , ~ . ;no-iiio .
; m c l i n pumping the water may 1.x rrgencr;iteil. The Iminpositioii of the gas escaping iron1 the dissolving water after pressure release will bc norinall)- a s sliown i n Table V I I I , the vsriation'_depenrii,,g u p o n opcra+,ii>Kconditioiis.
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 E E M I S T R Y
848
Vol.
12,
No. 9
The hydrogen and nitrogen dissolved represent about I O per cent of the total of these gases being manufactured. This loss is theoretically independent of the pressure a t which the scrubbing is done and is unavoidable since the solubility of hydrogen and nitrogen is not negligible. The carbon dioxide in the liberated gases is a valuable by-product. In con,unction with the ammonia synthesized, it may be used for the manufacture of ammonium sulfate by the decomposition of gypsum in the presence of ammonia, according to the equation CaSOn zNH3 CO, H 2 0 = CaC03 (NHI)SOo, or it can be used in the ammonia soda process zNI& COS 2H90 = 2NaIICOa zhaC1 zNH+CI = NalC08 COX H,O 2N&CI. There are available about 45,000 cu. it. of carbon
+
+
+
+
+
+
+
+
+
+
+
Pic
S-AM~I(ONIA CATALYST BoMa WlTX H B l T INTBRCPAN~.BRS ON TXE RICNT
ditions is prohibitive unless improved methods of recovery are developed ADDITIONAL PURIFICAlIOX-~%fter the cuprous S bing, further purification may be necessary depending on the sensitiveness of the catalyst used for the am-
ADJGSTMENT
T A B L E 1x-IIIP"RITIBs
scnvaarrrc Per ceot
ZN G I s APT*= CUPROUS
H.0 x (C€I*, arKOn, e*c )
Attempts have been made commercially t o remove most of the carbon monoxide by a concentrated hot Laustic solution6," preliminary to the cuprous scrubbing. Carbon monoxide and hot caustic soda produce directly sodium formate. Chemically the carbon monoxide removal is satisfactory, reducing the 3 t o j per cent inlet carbon monoxide down t o under I per cent when the optimum caustic concentration of I O per cent'* is used a t temperatures around However, the residual carbon dioxide in the gas causes a precipitation of insoluble carbonate from the solution, and the mechanical difficulties are enormous. The consumption of caustic under operating con-
OF
Cold
consisting of about 3 par with 0.5 t o 1.0 per cent of inert gases, such as argon and methane, passes into the ammonia circulating system. This is a separate and complete system wherein the entering gas acts as "make-up" t o replace the gas synthesized and removed as ammonia. The uncombined gases after removal of ammonia repeat the cycle through ogether with the added "make-up." Th hydrogen and nitrogen to the circulat hould be in the average ratio of 3 : I t o umulation of the excess of either constituent. The chemical composltion of the supply can evidently be best controlled by analysis of the gases in the circulating system where the cumulative effect of any slight inaccuracy of adjustment can he detected. The adjustment, if small, may be made by the injection of pure nitrogen or hydrogen obtai to run toward high adjustment may be Methane and ar
Sept,
1920
T H E J O U R N A L OF I
GINEERING C H E M I S T R Y
per cent in the entering gases temperatures and. therefore, must be employed.
The simples
of gas equal to IO per cent o maintain a concentration
allow uld
em ves
gas involve decreased ammon' the amount of purge and conseq costs. H E A T INTERCHANGE AND CATA
for ammonia synthesis is: The extent t o which
favorably altered creased by a rise i
'remgernture
30 A
promoters added.4
reaction is exothermic t o
available for maintainin
ing dangerous
t o a nitrificatio combined with viate much o f t
849
T H E J O U R N A L OF I N D U S T R I A L A N D EIVGIIVEERI.VG C H R M I . S I R Y
It
IS
evident that very low tcmperaturec are es-
a t 100 atmospheres pressurc with on in the liquefier, nearly half the ammon’
at
100
I)
atnlosphercs and delivering Raw Gns (M
IO
Vo1
12,
ho 9
ton7 o i ilquld
EU i t j
water-cas Pmdueer-cbs
Total
ting system are required
130
__ Total
14)
15
Power (k w .Mom CDmprECiOrS
Water Scrubber P
FTIC 441MOXI4 PLAUT AT SIIEFFIELD, ALABAMA
If alisorption of the ammonia b for the ammonia reaction e designs for the construction
cess about 60,ow Ibs
ernment and
OPEXATIXG Q L A X T I T I E S
ton of ammonia for a Haber-Bosch praces
Sept.,
1920
T H E JOURNAL OF INDUSTRIAL A N D ENGINEERING CHEMISTRY
The total cost of Nitrate Plant No. I was about cost covered t h a t of t h e nitric acid plant, t h e concentrating plant, ammonium nitrate plant, and t h e permanent village for officers a n d employees. The expenditure was only partly from t h e funds allotted under t h e National Defense Act. There is chargeable t o synthetic ammonia manufacture only about $ 7 , 0 0 0 , 0 0 0 of t h e total. Perhaps an additional $I,OOO,OOO should be charged for completing parts of t h e plant and installation. Based on t h e rated capacity of 60,000 lbs. of ammonia daily, t h e investment would amount t o nearly $goo per annual ton of fixed nitrogen capacity. The ammonia synthesis portions of t h e plant as installed consisted of three units, entirely independent of each other, not interconnected, b u t all under one roof. Unit No. I , t h e only unit upon which operation was attempted, was rated a t 15,000lbs. of anhydrous ammonia per day. Unit No. 2 was a duplicate of No. I , while Unit No. 3 was rated at 30,000 lbs. anhydrous ammonia per day. The total rated daily capacity of t h e plant was 30 tons of ammonia. The process t o be used was in general t h a t discussed in t h e first p a r t of this paper.26 Operation was t o be a t I O O atmoshheres pressure, or somewhat less, with ammonia removed by liquefaction. The raw gas mixture was t o be made directly b y t h e combined producer- a n d water-gas reactions. The carbon monoxide conversion was a t atmospheric pressure with any necessary additional heat supply t o be furnished b y superheating t h e admixed steam, or b y a free flame burning in t h e catalyst chamber. After condensation of t h e excess steam, compression t o I O O atmospheres followed, which pressure was maintained through t h e rest of t h e system. The removal of carbon dioxide was t o be accomplished in three stages, in series for t h e gas, with fresh water being supplied in parallel t o each of t h e stages. The larger part of t h e carbon monoxide was t o be removed b y hot caustic solution, and t h e balance of t h a t impurity by an ammoniacal cuprous carbonate solution. Final drying was accomplished by refrigeration followed b y t h e use of desiccating material. I n t h e circulating system additional heat was t o be supplied t o t h e gases entering t h e catalyst b y a tubular heater similar t o a steam superheater, and gas fired. The catalyst used was especially sensitive, being “composed of iron, sodium, and nitrogen.”l,18 The ammonia formed was t o be removed by liquefaction, refrigeration being supplied by a standard ammonia expansion installation, and t h e liquefied synthetic ammonia being discharged t o storage tanks provided for t h a t purpose. At t h e start of operations many difficulties immediately developed, a n d changes in process and apparatus became necessary. Initial operation of t h e plant commenced in June 1918 and t h e first synthetic ammonia was produced in September. Continuous operation was, however, never realized, and t h e plant was definitely closed in January 1919, after having produced only a small amount of ammonia. The raw gas manufactured finally developed into a practically $13,000,000,which
851
straight blue water-gas, with most of t h e nitrogen added later as air for flame combustion in t h e carbon monoxide conkerter t o maintain temperature there, while t h e overtaxed and inefficient steam superheaters were discarded. The compressors were quite satisfactory although under capacity when allowance was made for t h e hydrogen and nitrogen loss in t h e water scrubbers, in t h e inert gas purge, and in unavoidable leakage. The three water scrubbers operating with water in parallel gave much trouble and were inefficient in scrubbing and in water consumption, which difficulties were obviated by changing t o a one-stage scrubbing. The removal of carbon monoxide with hot caustic involved many difficulties which were overcome only by t h e elimination of t h e caustic system with its towers, furnaces, pumps, etc. All t h e carbon monoxide was finally delivered t o the cuprous solution for removal there. The cuprous system caused some difficulties a n d for improved absorption and efficiency reduced temperatures on both gas and solution were maintained. The purity of gas desired in view of t h e sensitiveness of t h e catalyst chosen was never obtained. I n t h e circulating system t h e catalysis and heat interchange were not self-maintaining in temperature, a n d use of the high-pressure heating furnace installed for supplying additional heat was continually necessary, although i t could not withstand t h e service for more t h a n a few days a t a time. Under-capacity of t h e r e frigerating installation, excessive friction of gas circulation, and large unaccounted-for gas loss were some of t h e additional troubles in t h e circulating system. There were innumerable incidental mechanical difficulties with valves, with joints, with pressure gages, and with mechanical labor-saving devices. Experimenting and development stopped in January 1919) and negotiations looking toward an arrangement whereby the General Chemical Company should continue with this work for t h e Government were not successful. As indicated above, many of t h e difficulties a t U. S. Nitrate Plant No. I had been overcome by changes in t h e process or development of apparatus; many others can now be overcome in view of t h e past experience; and t h e balance can be overcome by additional experimenting and development. T h a t final success can be hoped for is evident from t h e fact t h a t in Germany there are two plants-one a t Oppau with IOO,OOO tons of ammonia annual capacity, and one a t Mercersburg with 200,ooo tons rated capacity t h a t were in regular operation during t h e war. The former was started just before t h e war, and extensive additions soon followed. The latter was built mainly during t h e war and three-fourths of t h e rated capacity was in operation before t h e armistice was signed. The success of t h e German plants has shown t h a t a process of this type may be successfully operated under war conditions. It has not yet been proved, although i t seems probable, t h a t i t will be a commercial success under t h e post-war conditions t h a t have arisen. All reports from Germany point t o an optimistic feeling on t h e part of those connected with t h e industry there. N o doubt t h e government has a very
852
T H E J O V R N A L OF I N D U S T R I A L A N D ENGINEERING CHEMISTRY
Vol.
12,
NO. 9
8-Harries, J. Gasbel., 1894, 82; Luggin, I b i d , 1898, 713; Boudouard, considerable interest in the German plants,*’ and probAnn. chim. phys., 24 (1901), 1; Hahn, 2 physik. Chem., 44 (1900). 510; ably a large amount of t h e capital cost and all of the Ibid., 48 (19041, 735; Farup, I b d , 50 (1906), 276; Meyer and Jacobi. experimental cost has been written off as a war ex- J . Gasbel., 62 (1909), 282, 305; Clement, Bureau of Mines, Bulletin 7 (191 1) ; Haber, “Thermodynamics of Technical Gas-Reactions” (Longpenditure. mans, Green & Co., 1908). Conditions in America are somewhat less favorable 9-B. A. S. F., Brit, Patent 27,955 (1912); D. R. P. 292,615 (1912); for the private operation of a Haber-Bosch plant t h a n D. R. P. 293,943 (1913); Fr. Patent 469,907 (1913); Brit. Patent 16,494. Brit. Patent 11,878 (1910); General Chemical Co. (deJahn), in Germany because of higher labor costs and greater Brit. 10-Lane, Patent 124,761 (1918); Greenwood, “Industrial Gases.” installation charges. The determining factors may ll-Soci6t6 1’Air Liquide, Brit. Patent 15 053 (1914). Compt. rend., 94 (1882), 1355; Bohr and Bock, 12-Wroblewski, depend on the development of methods of utilization . Ann. P h y s . [2], 44 (1891), 318. of the ammonia and by-products, which in t u r n may W i d13-C. Bosch, 2. Electrochem., 24 (1918), 361. involve combinations with other known processes. 14-B. A. S. F., Brit. Patent 1,759 (1912); U. S . Patents 1,126,371 I n the German plants the combination of the ammonia- (1915); 1,333,087 (1915); D. R. P. 254,043 (1911); D. R. P. 279,954 (1913). 15-F. A. Weber, “The Action of Carbon Monoxide on Caustic Soda,” soda with t h e direct synthetic ammonia process has Dissertation, Karlsruhe, 1908; G. R. Fonda, “The Action of Carbon Monbeen accomplished with much success. This combina- oxide on Alkalies,” Dissertation, Karlsruhe, 1910. 16-B. A. S. F..D. R. P. 265,295 (1912); 1,075,085 (1913). tion may be of far-reaching importance in the develop17-Greenwood, LOC.cit., Patents by deJahn, Haber and LeRossignoI, ment of direct synthetic ammonia manufacture. I n Bosch and Mittasch. l&General Chemical Co. (deJabn), U. S. Patents 1,141,947 (1915); the United States, during the past year, t h e Solvay (19 15). Process Company and the General Chemical Company 1,143,366 19-B. A. S. F.,D. R. P. 259,870 (1911); 268,929 (1912) have together formed the “Atmospheric Nitrogen 2-B. A. S. F., D. R. P. 254.571 (1911): D. R. P 256.296 (1911): Corporation,” capitalized a t $j,ooo,ooo, for the pur- D. R. P . 275,156 (1911); U.S. Patent 1,188,530 (1916). A. S. F., D. R . P. 235,421 (1908); D. R. P. 259,996 (1911). pose Of nitrogen fixation in this country’ D. R.21-B. p, 270,192 (1912); U. s, Patent 1,202,995 (1916). I n Great Britain a corporation has been formed in 22-G. A Goodenough, “Properties of Steam and Ammonia” (3. which the Brunner-Mond Company (ammonia-soda Wiley & Sons,Inc., 1915). 23-Perman, J . Chem. Soc., 83 (1903), 1169; M. J. Eichhorn, in process) is financially interested, and which has S5,000,- “Ice and Refrigeration,” Chicago (August 1918). 24-“National Defense Act,” approved June 3, 1916, Public Docu-000 available capital t o design, build, and develop ment, War Department, Bulletin 16, June 22, 1916. the direct synthetic ammonia process. 25-”Statement of Action Taken and Contemplated Looking t o t h e The situation with regard t o private operation of Fixation of Nitrogen,” by Division T, Ordnance Office, War Department, a plant in this country does not apply t o the govern- Aug. 21, 1917, THIS JOURNAL, 9 (1917), 829. 26-General Chemical Co. (deJahn), Brit. Patents 120,546 (1918); ment plant a t Sheffield, Alabama, built as a war 124,76&1-2 (1918). emergency measure. There the United States o w m 27-N. Caro, Chem. I n d . , 42 (1919), 877. a complete plant designed t o produce ammonia by a direct synthetic process. It had not reached an GASOLINE FROM NATURAL GAS. 111-HEATING VALUE, operative stage a t t h e close of the war, and conSPECIFIC GRAVITY, AND SPECIFIC HEAT siderable alterations will have t o be made before it By R. P. Anderson can be considered operative. The Nitrate Division UNITEDNA TURAI, GAS COMPANY, OIL CITY PENNSYLVANIA of the Ordnance Department, U. S. A., now has under Received May 12, 1920 way plans and redesigns for t h e modification of U. S. ’ T h e present paper of this series on natural-gas Nitrate Plant No. I t o bring t h a t plant t o successful gasoline problems is devoted t o a discussion of t h e operation. This should by all means be done as a following topics : military preparedness measure. It will be recalled ( I ) Relationship between heating value and numbyr t h a t Germany did not embark upon the World War of carbon atoms per molecule of hydrocarbon. until she had two independent nitrogen fixation pro( 2 ) Relationship between heating value and specific cesses-the cyanamide and the Haber-commercially gravity of gasoline. developed. This country should not, after the lessons (3) Effect of removing gasoline upon heating value of the war, permit itselffto be in a less favorable posiand specific gravity of natural gas. tion than was Germany six years ago. (4) Specific heat of natural gas a n d gasoline vapor. REFERENCES 1-F. Haher and R. LeRossignol, Ber., 40 (1907), 2144; 2. Elektrochem., 14 (1908), 181; Ibid., 19 (1913), 53; F. Haber, Chem.-Ztg., 34 (1910), 345; 2. Elektrochem., 16 (1910), 244; F. Haber, et a l , Ibid., 20 (1914), 597; Ibid., 2 1 (1915), 191. 2-Haber, D. R. P. 229,126 (1909); 238,450 (1909); Haber and LeRossignol, u. S. Patents 971,501 (1910); 999,025 (1911); 1,006,206 (1911); 1,202,995 (1916); Badische Anilin und Soda Fabrik, D. R. P. 235,421 (1908); 259,996 (1911). 3-B. A. S. F. (C. Boseh), U. S. Patent 1,102,716 (1914); Brit Patent 26,770 (1912); Fr. Patent 459,918 (1913); General Chemical Co. (deJahn), Brit. Patent 124,760 (1918). 4-H. C. Greenwood, “Industrial Gases,” (Ballisre, Tindall & Cox, 1920). 5-B. A. S. F., Brit. Patent 27,117 (1912); (C. Bosch) U. S. Patent 1,115,776 (1914); (C.Bosch) U. S. Patent 1,200,805 (1916). &General Chemical Co. (deJahn), Brit. Patent 120,546 (1918). 7-Vignon, Fr. Patent 389,671 (1908); B. A. S. F., D. R . P. 282,505 (1913); Brit. Patents 8,030 (1914); 9,271 (1914); U. S. Patent 1,196,101 (1916); D. R. P 289,106 (1914); General Chemical Co. (deJahn), Brit. Patent 120,546 (1918).
(I) RELATIONSHIP B E T W E E N HEATING VALUE AND NUMBER OF CARBON ATOMS P E R MOLECULE
If the assumption be made t h a t the relationship between t h e heating value of normal paraffin hydrocarbons, expressed in calories per gram-molecule, and the number of carbon atoms per molecule is a linear one, it becomes a simple matter to compute tables of heating values t h a t are valuable in the natural-gas gasoline industry. Such computations have been made for t h e heating values per lb., per gal., and per cu. f t . of vapor of the normal paraffin hydrocarbons, pentane to undecane, inclusive, and the results are incorporated in Table I. Thornsen’s figures for the heating value of methane, ethane, and propane form the basis of t h e table and have been included in it.
