COLLF.CTIONS IN ECONOMIC OKOLoOY AND M KIM, I, Tin; V. 2')! 

 TllK TKEATMKNT <»l I'K IHoLKT M. 



A very siiiiill aiiicMini dl jM'tiolciim linds tliicct application in ilu- 

 )>ivp:ii'ati(>n of special Inlnicalors. .Most petroleum is, liowever, siiU- 

 jected to tlistillation in order to olMain the vaiious products in a state 

 of jMirity snitaltle for particular uses. 



Fornu'rly it was the plan to subject tlie crude petr()leuin to i)lain «lis- 

 til!ati(»n l»y healin]Lj it to certain reijniated temperatures to separate the 

 constituents vohitile lit tliese teuipenitiires. By this operation (tnl\ 

 slij,dit chemical chan;;es took placo during the optMation, and there 

 always lemained a larj^e amount of darU, heavy oil, havin<; a stronj; 

 otlor, which found little or no apjdication. 



About 18(]5the process of destru(;tive distillation or "crackinj;" was 

 introduced. This was so successful that it was rapidly adoi>ted, and is 

 now uniformly used in this country. 



In this process the most volatile portions of the crudt; p»;troleum are 

 lirst removed by plain distillation at about 101)^ C. The residue is then 

 heated at once to a hi^^h temperature. Hy this operation the heavy oils 

 lire broken up "cracked" and a much lar^^er yield of li^Miteroils suita- 

 ble for illuminating purposes obtained ; at the same time a cotisiderable 

 amount of fjas is produced, which is utili/ed for lieatinj; juirpo.ses about 

 the works. The residue romainiui,' in the still constitutes oidy a small 

 per cent, of the orifjinal crude petroleum, and is further treated. 



The dirterent distillates are subjected to a further treatment to pre- 

 pare commercial juoducts. Sometimes chemicals are used in this re- 

 treatment. The fiind products are divided according; to their specilic 

 gravity Ity the HaumT' scale. 



Professor Peckham gives the following tables* of the pr«Hlucts trom 

 the process as ordinarily conducted. The first treatment at KHP C 

 gives oft" 12 to 15 per cent., whi(;h on retreatment yields : 



IVrcent. 



1. "Crude ga«ohue," to 80^, about i 



li. "C" naphtha, 80^ toG8^, ahout 10 



:!. " H " ii.ii)htha, «>s^ to (M-', alxmt *_' to 2| 



>. ' A " naphtlia. i'>\ to t»u^. ahuiit -J to 24 



The residiu' sultjected to crackiiii; \ ields : 



!• Ill 



1. ( "mile buruiu;; oil. from .'i-' to li) ,;iIm>iiI ... .">(i 



•J. •• 15" oil, from m to :sr> , altoul -JO 



'.i. KroiM 'M't-' ihiwuwanl, ahout Si 



4. CokiiifTS or n'.siiliiiMu ;{ 



r>. LOMH -J 



KM) 



These produ(;ts are treated in various ways to improve tiieir ipialify, 



to separate the oils of ditferent specilic gravity, ami to obtain tlie par- 



aftin. The parallin is separated b\ cmtlinL; the heavy oils containing it 



• Tenth CfiiHiiH Heport on I'drujciini, \ol. x, jij). U>4 nn<l U'».'>. 



