JUYE, 1935
INDUSTRIAL AND EXGINEERING CHEhlISTRY
formed" to improve its octane rating. Of the 206,486,000 ilarreli of straight-run gasoline produced in 1931, more than 50,000,000 barrels viere "reformed." The cracking process l)roducec1 182.4:33,000 \,arrels ( 2 ) of high-antiknock gasoline in 1934. The cracking proce= of today with its multiple heating coil operation ha. a degree uf flexibility undreamed u f a fern y e a r ago. C o n t i n u OII- cracking runs of over n i n e t y day5 a r e now coininon, as compared to cycles of o n l y a f e w days about twenty years ago. The widest variety of stocks are c r a c k e d to p r o d u c e highantiknock gasol i n e , g a s , and inetallu r g i c a 1 coke; and at the w n e time, when deiired, t r a c t or fuel, furnace o i l , D i e s e l oil, or fuel oil. Tenlperaturei iri niodern cracking unit.: range froni about 475' to OTW 600" Cy. (887" to 1112" F.:i and pressures from atmospheric t o over 1000 pound.< per square inch. The cracking procesi is the greateGt force for con>ervation that lias been developed iii tlie oil induqt'ry. C I refiner> had been forced to produce, vitliout crackinq, the lT.i85.000,000 gallons of gasoline needed to operate our 25,0ilO,000 inotor cars in 1934, about, double the volume of crude oil \rould have been required t,han Tyas actually refined. Axtell J. Byles, president of tlie -4mericnn lktroleuiii Institute, emphasized tliis point in a recent statement : "To have produced last year's gasoline requireiiients by the pro('esse5 in use in 1917, it xvould have been nece3sary to have run I,866,000,C00 barrels of crude oil. In 1931, tlie industry actually supplied t,lie gasoline requirements by running 893,000,000 liarrela of crude oil. T h a t is real conserv-atioit of a limited natural resource." This conservation n-as accoinplibhed largely through the use of the cracking process. \
I
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u
Antioxidants By systematic research it has been discovered that much of t'he refining of cracked gasoline can be eliminated by the use of chemicals called "inhibitors" or "antioxidants." Cracked gasoline contains certain unsaturated hydrocarlions xliich, in contact with air, oxidize to form gum. Former practice was to reniove these gum-forming coinponerits by treatment with sulfuric acid, clay, or catalytic processes. Such chemical treatmenti of cracked gasoline polymerize some of the unsaturated hydrocarbons to heavier oils, causing a volumetric loss of 1 to 5 per cent of gasoline and an octane rating loss of 1 to 2 nunibers. By reducing voluinetric losses, eliminating cost of chemicals, and preserving octane rat>ing of the cracked gasoline, the use of inhibitors is saving $15,000,000 a year to refiners.
651
High-Sulfur Gasoline Since the advent of the cracking process, it has been passible to produce motor fuel from high-sulfur oils which previoudy were not readily refinable. Cracking of wch oils produce5 ga soli n e bonietimes containing 0 5 per cent of sulfur or more. To b r i n g s u c h gasoline in line with federal specification. of 0.1 per cent .ulfur requires drastic refining with sulfuric acid. This results in d u n i e t ric loss aq high as 30 p e r c e n t and octane lo+ as h i g h a s t e n number5 in extreme cases. Extt3nbive rebearch, c a r r i e d on in laboratories and in m o t o r cars on t h e road, has showi that no liarni results from using gasoline containing inore than 0.1 per cent' of sulfur. Acting on this knowledge, a number of refiners are actually marketing every gear billions of gallons of gasoline containing u p to 0.25 per cent' sulfur or higher without corrojion of motor car engines. I t is estimated it would cost refiners S10,000,030 a year t o reduce the sulfur content of their gasoline from the harin1u.j~ 0.25 per cent point to the needlessly severe specificati:xi of 0.1 per cent.
Cracked Gas Tlie cracking process is producing yearly about 303,000,000,000 cubic feet of gas mliich contain3 high percentage3 of olefin 1iydrocar~)ons. An olefin polymerization proceis has been developed n-liich will produce from this gas, motor fuel having 82 octane number or, on a blending basie, 120 octane number based upon tlie C. F. R. motor method. From 3 to 12 gallons of motor fuel are obtained per thousamridcubic feet of cracked gas, depending upon tlie percentage of olefin, present. It has lieen found p o d & t o produce 100-octane motor fuel by polymerizing the ijobutylene present in cracked gases into diisobutylene and then hydrogenating to isooctane. When 100-octane fuel n-as tejted in an army pursuit plane, it gave 35 miles an hour more speed than a motor fuel of 92 octane number. \Then 100-octane g a d i i i e is geiierally available (which may be soon), the rated horsepower of engines using it will be iiearly doubled. IS it, not probable that this accomplishment mill speed u p commercial airplane3 t o 500 miles per hour, instead of the 225 of today'? The chemical industry is ut,ilizing the olefins present in cracked gases to produce alcohols, glycols, alcohol ethers, ethers, oxides, aldehydes, ketones, est'ers, acids, anhydrides, chlorinated compounds, amines, and vinyl resins. It is also
652
INDUSTRIAL AND ENGINEERING CHEMISTRY
CRACKING U E I T (CAPICITY,
5000
B.4RREL.3 PER
finding uses for such hydrocarbons as methane, ethane, butane, isobutane, ethylene, propylene, and butylene. The Carbide and Carbon Chemicals Corporation recently started operating a $10,000,000 plant at Whiting, Ind., to utilize the cracked gases for chemical derivatives. The same company has had a similar plant operating for a number ot' years in the South.
Other Products from Cracking Furnace oil produced b y cracking has low viscosity and low cold t e d with high heating value. At seasons when it is more profitable to do so, the cracking unit is operated to produce more furnace oil and less gasoline. Excellent tractor fuel of high octane number can be readily produced by controlling the operating conditions of the cracking unit. Cracked fuel oil excels straight-run fuel in a number of rejpects. It has a low cold test, low viscosity, and about 10 per cent more B. t. u. per barrel. This last property i. particularly important in ships and locomotives where hunker space is a primary consideration. Over 200,000,000 barrelb of this high-quality cracked fuel oil are produced yearly in the United States. Over a million tons of coke are produced annually from the cracking process; much of it is used for metallurgical purpose, and for the manufacture of electrode.. Cracked road oils and asphalt are finding ever wider use. The quality of the asphalt can be controlled so as to make it suitable for uses- aside from road-making. Among these are roofing, shingle saturants, coating asphalts, floorings, and emulsions. Over 2,000,000,000 gallons a year of liquefied propane and butane are available from the gases of the cracking process and are being introduced to new markets. Propane and butane in pressure tanks are being used as fuel in motor busses and rail cars. One of the latest uses for propane is in dewaxing and deasphalting petroleum oils and also for solvent extraction of lubricating oil. Propane and butane also are being cracked and polymerized into high-antiknock motor fuels.
Natural Gas Gasoline The natural gasoline industry produced 36,217,000 barrels of gasoline in 1934, and important improvements have been made in its recovery. The chief of these is the development
D 4Y)
FOR
I-OL. 27, NO.6
REFORMING G.4s01,Il.H
of the stabilizer which removes the wild fractions, propane and butane, and leaves a stable motor fuel of any desired yapor pressure. By modern methods the gases processed in 1934 yielded about 12,000,000 barrels more gasoline than could have been obtained from the same volume of gas by the processes of twenty years ago.
Lubricating Oil The great increase in average driving speeds has led to the development of oil of improved quality for motor car lubrication. Eight years ago the low-priced cars ranged between 20 and 30 horsepower, with corresponding speed limits. The 1935 models of these same makers have 80- to 90-horsepoffer engines, capable of sustained speed of 80 miles a n hour. Xodern speeds call for low oil consumption, which is based upon the properties of high \-iscosity index, low carbon content, high resistance to oxidation and sludging. T o produce such motor oils, the industry is rapidly eliminating the old costly chemical treatment in favor of solvent extraction, propane dewaxing, acetone-benzene dewaxing, or addition of substances to lower the pour point and improve the viscosity of the oil. Solvent extraction is a physical separation of the molecules which have high lubricity or oiliness and tough film strength from those poor in these properties. Most refiners today are operating, installing, or contemplating the installation of one of the solvent extraction processes, such as Chlorex (dichloroethyl ether produced synthetically from cracked gases), phenol; mixtures of d f u r dioxide and benzene; nitrolienzene, aniline; propane and cresol, furfural, acrolein, crotonaldehyde, or a mixture of nitrobenzene and sulfuric acid. When all the lubricating oil is produced by solvent refining, the savings to the motorist \-,-ill bs enormous because he mill obtain more miles to the gallon and his engine will suffer h i s wear. The cracking process is playing its part in the development of new lubricating oils, as well as superior motor fuels. One of the latest developments of cracking is the catalytic polymerization of certain fractions of cracked gasoline into motor oil. The oil thus produced has high viscosity index, low Conradson carbon, and high resistance to oxidation. One company has made this oil by cracking wax distillate and then polymerizing the unsaturated fraction by aluminum chloride.
t,lievertical. Soinctiiires drilling (wokad holes serves i i useful purpose. More tliltii one oil well fire 1ia.s heen extingnislrr.d by drilling a slnrrting liole t.hmugIr wliioli \miter coiild be piitiiped into the oil sand which was feeding fuel to the fire. 0 t h iniprovenicnts in the nietliodb i l i quenclririg oil fire. have aeeoiiiplished large savings. The ability ti, drill straiglit,er a i d deeper has brought to light oil sands in many field,? which \%-ereunsuspected before. For iiistanc.e, oil has heen in tire Carber field of Okinhor~~a, produced from twenty-three separate sands. Another important accornplishrnent of pro(luetion engineers has been in recovering great qirantities of oil which \\.ere left in the sand when the naturnl g a s preriiure s u b s i d e d . 1 he siniglest of these methods is tlic improveIT
iririit of the t,ecliiiic of d e e p w e l l pumping. Oil is now heirrg hrought t o the surface froin :idepth pievioiisly helieved to l i e beyond the rr:srli of the purrrp. Another xirctlii,d is the restoratioii atid maintenance of pressure on oil sands. This is aecoml~lished io several ways. Pumping Ilark into the sard stripped rratirral gns, or air, is probably the most important. This niethod is particularly effective in unit operntiinis, where a fieldie closely held by a liuinbcr of companies wlio couperate on conrervntion rneasiires. The p r a c t i c e is t o pass the gas tlrrwgli natural gasoline plants tu extrnct tlic gasoline and then to pump the residue gas Imek into thi. sands. Flimdirig oil sards xit,ii water is also effeetive in sonic fields, increasing oil produetiun more than tenfold. Somewhat older r n o t l i ~ i sfor increasing oil
7 4”
FLOW CH4RT
OF SHELL-STILL
D~STILLVITO\ O F P i R 4 F F I N - B 4SE
O I L TO P R O D U C E L I G H T O I L S 4\L) LLBHIC.4NTS
recoyeq- are bliooting nit11 nitroglycerin and the application of x-acuiiiii tn tlie ~ ~ 1 Sometimes 1 ~ . a dry hole is converted into an oil producer liy shootiiig -1new nietliod is tlie use of li-drochloric acid, especially in
linrestoiie formatioils. The a7-erage increase in oil production on three thousand atidized n-ell. oii ~ d i i c hrecords were kept, was 448 per cent. ;1n~nnI)erof dry holes l i a i e lieen tiirnetl into eonniiercial producer^ hy acidizing. It is estiiirated that over 200,000,000 lmrrel. of eniulsified oil are produced yearly. \-ear. ago, tlii.: eniul4fied oil n-as riin into sunips, rewlting in heavy loss. Howe.,-er, diligent re*earcli dereloped coniniercial mean.: for recovering cleaii oil fr(in1 these emul.ioiiIiiies, .llorithiy Pefroietcm S f n l e n ? t n f128 ( F e h . 5 , I!) RECEIVED.\pril 1, 11135. Presented before the Ilivision of Petroleum Chemistry a t the 8 9 t h Xeeting of t h e ;\meri
