1914
INDUSTRIAL A N D ENGINEERING CHEMISTRY
(242) Taylor, V. T., and Hebden, D., Gas Research Board, Copyright Pub. GRB 42 (1948); Gas World, 12.9, 799-802, 884-9 (1948); Ibid., 130, 126-7 (1949). (243) Teichert, W., and Hansson, O . , Ing. Vetensleaps Akad., Peat Lab. Communication, 4 (1948). (244) Tejnicky, B., Paliva a voda, 28, 105-12 (1948). (245) Terbeck, X., Glzdcicauf,84,327-30 (1948). (246) Thau, A., Gas- u. Wasserfach, 88, 97 (1947). (247) Ibid., pp. 136-40. (248) Thau, A., Oel u. Kohle, 37,217-29 (1941). (249) Thibaut, C. G., Rev. tech. Zuxembourg., 39, 144-66 (1947). (250) Toplin, J. G., Chem. Eng. News, 26, 3096 (1945). (251) Trifinov, I., Annuaire univ. S o f k . XI. Faeult6 phys.-math., Ldwre 2, 40, 173-6 (1943-4). (252) Van Meter, R. A . , Neel, J. C., Brodie, E. C., and Ball, J. S., preprint, Division of Petroleum Chemistry, 115th Meeting AMERICAN CHEMISTRY SOCIETY, San Francisco, Calif. (253) T'ian, A., and Blasco, E., Ion, 7 , 227-30 (1947). (254) \7ykoukal,J., Paliva avoda, 28,543 (1948). (255) Ward, S. G., Gas Rev., 2, 333-4,336-40,342-4 (1948). (256) Ward, 8. G., Gas Times, 14, 168-70 (1948). (257) Wardner, W. C., Am. Gas. Assoc. Monthly, 30, No. 10, 30-1, 36 (1948).
Vol. 41, No. 9
Wardner, W.C., Gas, 24, No. 7 , 60 (1948)). Weiss, J. M., Chem. Eng. News, 26, 238-40 (1948). Weiss, S., Dreprint, Joint Production Chem. Comm. Conf., Am. Gas Assoc. (1948). Westergardh, A. H., Sverigea Geol. Undersdkn., Ser. C , No. 483, Arabok 41 (1947).
Wethly, I?. (to Allied Chemical & Dye Gorp.), U. 9. Patent 2,460,324 (Feb. 1, 1949). Widell, T.,lva, 18, 178 (1947). Willcox, 0.W., World Petroleum, 18,88(1947). Wilson, P. J., Jr., and Wells, J. H., Blast Furnace Steel Plant, 36, 806-12, 961-4 (1948).
Wood, J. W., Gas Research Board, Commun. No. GRB 33 (1947). Young, E.W., Am. Gas Assoc., Proo. 29, 698-700 (1947). Young, E. W,, Ga8 World, 127, No. 3281, Coking Sec., 121 (1947). Zhunko, V, I., and Orochko, D. I., U.S.S.R. Patent 68,324 (April 30, 1947). (270) Zieseoke, B. H., U. 8. Dept. Commerce, OTS Re&, P B L 73874 (1939).
RECEKVED July 5 , 1949.
Pyrolytic and Catalytic Decomposition of Hydroca
mx
VLADlMlR HAENSEL and MELVIN J. STERBA UNIVERSAL
OIL PRODUCTS
OLLOWING the first literature review (44) on the subject
F
of hydrocarbon decomposition reactions, this summary includes an inspection and brief digest of material that has appeared in the literature during 1948 and the early part of 1949. The past year has noted the continuation of fundamental experimental work in both thermal and catalytic decomposition reactions. The refining industry has continued in its trend during the past year in increasing its capacity of catalytic cracking, for which several modifications and improvements have appeared.
THERMAL CRACKING Several publications have appeared concerning the thermal decomposition of pure compounds. These reactions have been studied mainly from the standpoint of product distribution, reaction kinetics, and reaction mechanism. The thermal decomposition of n-hexadecane a t 500" C. and atmospheric pressure has been shown by Voge and Good (106) to be in good agreement with the predictions of the Rice radical chain theory, as amplified by Kossiakoff and Rice, from the standp o h t of product distribution. Rice and Haynes (89) in their studies of the thermal decomposition of isobutylene (%methylpropene) report that under proper conditions the reaction occurs without the formation of carbonaceous and tarry material. At temperatures of 630" t o 945" C. they found allene and methylacetylene as major products of the reaction, although they did not determine whether the methylacetylene was produced by isomerization of allene or by decomposition of isobutylene. In their studies of the thermal decomposition of +hexane in a static system at 500" to 620" C., Partington and Danby (89) found that the relative probabilities of initial rupture of C C bonds in positions 1, 2, and 3 were in the ratio 3.9 to 2.5 to 1. They also found that when the chain b r e a b in position 2, the chances me more than 10 to 1 that ethane and 1-butene will be found rather than ethylene and butane. Vanas and Walters (103)studied the thermal decomposition of cyclopentene in a statio syatem a t temperaturm of 483"to 548' C.,
COMPANY, RIVERSIDE, ILL.
and a t pressures of 35 to 249 mm. of meroury. Under these conditions the principal reaction was found to be the dehydrogenation of cyclopentene to cyolopentadiene, a t least in its early stages, when i t was indicated t o be of first order. The thermal decomposition of Zpentene and trimethylethylene has been studied by Hepp and Frey (47) in quartz a t 778" t o 850" C. in the presence of varying amounts of steam. At the most favorable conditions, butadiene was the major product from 2pentene, although smaller amounts of pentadiene were also found. Trimethylethylene yielded isoprene and butylenes as the major products, along with smaller amounts of butadiene. Thermal cracking of propane-l-Cla a t temperatures of 500" to 550" C. (98) has given evidence of an 8% greater frequency of rupture of C1S-Cl2 than of C11-CP bonds. However, the C ' L H bonds appeared to be less stable than C'2-H bonds. Methane decomposition a t temperatures of 1000" to 1100" C. has been studied by Gordon (41), who observed that the first order rate constant increased with increasing decomposition. He showed a catalytic effect of acetylene on this reaction, and used this observation as an explanation for the increasing first-order rate constant, since the percentage of acetylene in the producte increased with conversion. A catalytic effect of porcelain surface on the decomposition of methane was reported, In a German process (6),methane was cracked in a regenerative type thermal reactor at 1400" t o 1600" C. and a t 0.1 atmosphere pressure to produce an ultimate recovery of 3670 acetylene. The necessity for low pressures was reported ae the main disadvantage of the process which involved 1-minute processing periods and 1-minute heating periods. A commercial unit was designed on the basis of pilot plant operation but was not built. During the processing period a certain amount of methane is decomposed t o carbon, which deposits on the reactor packing, and provides about 40% of the heat required during the reheating portion of the cycle. The ratio of acetylene t o carbon production was sa5d to depend critically on the operating pressure.
September 1949
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
The vapor phase cracking of Fischer-Tropsch waxes a t temperatures of 500" to 640" C. was studied (31) for t h e production of olefins. Although ethylene was the principal reaction product substantial amounts of a?-olehs could be recovered from t h e cracked material. Seymour (03) studied the stability of polyeth and polyisobutylene b y noting the lowest t e volatile hydrocarbons were formed and relative stability of these high polymers wa Polystyrene having a molecular weight of 230,000 was decomposed thermally by Madorsky and Straws (64)at 350" t o 420' C. in a vacuum of 10" mm, of mercury. Decomposition products included a solid residue, a waxlike fraction, styrene, toluene, . 4
times u p t o 4 hours.
r.
stated t h a t catalytic cycle oi
cracking (TCC) process, continuous contact with particles which flow by
*
t
air and gas in the solids bed. Several tures are presented for the pilot plant cracking of ethane, propane, and a variety of crudes for the production of ethylene a t temperatures of 1500" to 1800" F. In addition, aromatic yields are presented for t h e processing of crudes and two catalytic cycle etocks. It is claimed t h a t any carbon formed in the reactor is continuously removed by the solids and transferred to the heater where i t is burned to provide a part of the heat requirement of the process. Tighe (100)has related the yields of various products of thermal re-forming of naphthas to a re-forming number which i s computed as a function of temperature, time, reaction rates, and the paraftinicity of the feed stock. Such relationships are presented in graphical form for three straight-run naphthas, along with a plot of t h e increase in octane number against the re-forming number. His method is essentially one of plotting product distribution and octane number improvement against operating conditions, as compared with the conventional method of relating product distribution and quality to depth of reforming. Goldtrap and Jones (No)have presented a correlation for selfcontained naphtha polyforming which they define 813 the thermal treatment a t high pressures of naphtha in a coil in t h e presence of recycled gases, mostly CS hydrocarbons originating from t h e naphtha itself. The correlation shows that more gasoline of a higher octane number is obtainable from self-contained polyforming than from conventional thermal re-forming at the same pressure and cracking severity. This was expIained by stating t h a t higher yields and octane numbers resuIt from the formation of increments of high-octane polymers and alkylates from the recycled gases and the naphtha undergoing decomposition. Octane number sensitivities of the polyformed gasoline have been related t o the severity of treatment, operating pressure, and characterization factor of the feed stock.
1915
Offutt, Fogle, and Beuther (80) describe the utility of the polyform process in converting extraneous gas streams, and particularly highly olefinic G and C, fractions from catalytic cracking, into motor gasoline. They point out t h a t the highest gasoline production is assured by maintaining the charge rate of naphtha m and the olefin content of the circulating gas stream eve]. Numerous aharts are presented relating the ctane number of gasoline obtainable at various gas olefin contents for the polyforming of midcontinent naphthas Pilot plant and commercial thermal cracking of petroleum fractions from a given geographical source has been shown by Barron, Vander Ploeg, and McReynolds ( l e ) t o produce gasolines having sulfur contents that are directly proportional t o the sulfur content of the feed stock. However, the proportionality depending on the source of led the sulfur factor (ratio sulfur concentration in feed) abian stocks t o 0.34 for California stocks. for the thermal decomposition of petroleum enriching water gas has been of utilizing the heavier hydromaterials for chemical manuached b y a study of variables t o increase the ratio of liquid intermediates t o gas and tar, by a study of tar processing methods, and by a program of chemical research on product utilization. The authors indicate, however, mpany is not organized for procx chemical products, and suggest job better suited t o chemical in-
r producing chemicals from petroe process (11) was p u t into operation in e past year. It was stated t h a t this process liquids from which more than 70 different TALYTIC CRACKING CHEMICAL CONCEPTS The work on catalytic cracking in 1948 and the early part of 1949 can be divided into three parts: reactions and mechanism of cracking, structure of cracking catalysts, and methods of evaluation of catalysts. Ciapetta, Macuga, and Leum (86)reported a n investigation on the catalytic depolymerination of butylene polymers. The catalysts used were Attapulgus clay, synthetic silica-alumina, and solid phosphoric acid, AI1 three catalysts produced a gas fraction consisting almost entirely of CI hydrocarbons; however, Attapulgus clay produced a 94 t o 100% isobutylene concentration in the C, cut, while phosphoric acid and silica-alumba gave 87 t o 91% and 64 t o 85% isobutylene concentration in t h e C, cut, respectively. I n this particular case diisobutylene was used aa the charging stock. The lower selectivity of reaction in the presence of t h e synthetic silica-alumina catalyst is attributed t o t h e more pronounced hydrogen transfer ability of t h a t catalyst. The mechanism of depolymerination is explained in terms of the carbonium ion theory. According t o Funasaka and Horikawa (57), t h e decomposition of cetane occurs more effectively with alumina gel than with silica gel, tho former producing more aromatic compounds. Aromatic compounds are also formed with active charcoal. Ipatieff andschmerling (68) reported on the effect of hydrogen on action of aluminum chloride on alkanes. They found that autodestructive alkylation occurs when n-pentane reacts with aluminum chloride in the presence of nitrogen. At t h e same conditions, but in t h e presence of hydrogen, there is essentially no reaction. Similarly, under a hydrogen pressure but in the presence of hydrogen chloride and aluminum chloride, n-pentane undergoes isomerization to isopentane (2-methylbutane), whereas under a
8916
INDUSTRIAL AND ENGINEERING CHEMISTRY
Modern
Fluid Catalytic Cracking Unit
nitrogen pressure t h e reaction IS that of autodestructive alkylation. With higher molecular weight paraffins, such as n-heptane QF kogasin, hydrogen does not prevent t h e autodestructive alkylation reaction. Kemball and Taylor (67)investigated the catalytic decomposition of ethane and ethane-hydrogen mixtures using a 15% nickel on kieselguhr catalyst. It was found that ethane alone decomposes quantitatively a t 182' C. according t o the equation: 2CzHe --P 3CHd
Vol. 41, No. 9
+- C
The carbon formed on the catalyst can be removed by treatment with hydrogen at the same temperature without any progressive poisoning of the catalyst. Ethane-hydrogen mixtures having a n excess of hydrogen gave methane, the rate of reaction being dependent on pC2H&' X PH~-'.~, whereas, with ratiGs containing a deficiency of hydrogeri, there was an increase in the rate Jf reaction above that expected from the kinetic expression. The rate-determining step of methane formation must be the breaking of the carbon-carbon bond, and the authors postulate a mechanism wherein adsorbed ethylene is present on the surface in equilibrium with adsorbed ethyl radicals and hydrogen. Parravano, Hammel, and Taylor (81) studied the exchange reaction between methane and deuteromethanes on silica-alumina catalysts. The investigation was based on the idea that the cracking of petroleum hydrocarbons on silica-alumina catalysts cannot occur unless the carbon core of a hydrocarbon chain can come within the radius of chemical interaction with the catalyst surface, and, in order t o effect this contact, a t least one of the carbon-hydrogen bonds must bP hroken. The uuthors showed that
the exchange reaction between methane and deuteromethanes occurs readily a t 345' C . in the presence of a silic*alumina catalyst. Because the exchange occurs at temperatures much below the cracking temperatures, i t is reasonable to assume that a dehydrogenation reaction is the f i s t step in a cracking process, following which a catalyst-carbon linkage is established, and this is in turn followed by the carbon-carbon cleavage. Morton and Nicholls (88)investigated the decomposition of 1 , I-diphenylethane t o styrene according to the rea,ction:
The catalyst employed was Morden bentonite, a Canadian clay, which is essentially of the montmorillonite type characterized by a rather high percentage of combined water and low percentages of alkaline earth substituents. The clay was activated with a boiling 20% solution of sulfuric acid followed by washing. I t was found that a regenerated catalyst produced larger amounts of styrene than a partially carbonized catalyst, and this in turn produced more styrene than a fresh catalyst. In general, higher temperatures produce increased conversions as well as increased atyrene contents in the converted product. A maximum styrene content is reached a t about 600"C., the optimum conditions for 3tgrene production being rapid feed rates and the use of water ap diluent. The water serves t o cut down on the extent of side reactions as well as to remove the carbonaceous deposit.
September 1949
INDUSTRIAL AND ENGINEERING CHEMISTRY
Smith and Lo (96)investigated the behavior of various dialkyltetralins in the Jacobsen reaction. When 6-isopropyl-7-methyltetralin was heated with sulfuric acid to 95" C. for 15 minutes, the product obtained contained 6-methyltetralin, the isopropyl group having been eliminated. On the other hand, 6-n-propyl-7-methyltetralin yielded 54-propyl-6-methyltetralin in a 25% yield. In the last case, the tetramethylene ring undergoes migration rather than either alkyl group. The conversion of the montmorillonite to spinel by heating was investigated by Grenall(4a). X-ray diffraction analysis was used to follow the conversion of a commercial grade Filtrol catalyst, and the phases identified were correlated with catalytic activity. The fresh catalyst was found to contain montmorillonite as the major constituent, while quartz, gypsum, and anhydrite were minor components. Heating at 1050' F. produced a conversion of gypsum to anhydrite and caused a large decrease in the long spacing reflection of montmorillonite. From 1050' to 1475' F., the intensity of the montmorillonite pattern was reduced until this phase was completely destroyed a t 1560' F. At this point a faint pattern of a spinel-like structure was observed. Finally, after heating to 1830 O F. the composite conaists of spinel quartz, anhydrite, sillimanite, and mullite. Simultaneous with the disappearance of montmorillonite, there is a sharp reduction in catalytic activity. The author postulates a mechanism of deactivation based on the removal of combined oxygen and/or hydroxyl group from the lattice, so that the negative charge responsible for the ion adsorption properties is reduced. The relationship between catalytic activity and ion exchange ability of aluminosilicates was studied by Bitepazh ( $ I ) , who found B rough correlation between the cation exchange capacity of natural clays and kaolin and the catalytic cracking activity. The elementary structure of alumina catalysts was investigated by Oborin (78). The author ascribes the catalytic action of alumina to y-alumina which can contain doublets of aluminum atoms on adjacent molecules. The distance between these aluminum atoms is 2.56 A., which is very close to the value of 2.51 A. representing the distance between alternate carbon atoms in a hydrocarbon chain. The conversion to the cy-alumina form by heating produces greater interatomic distances and reduces catalyst activity. Silica as a carrier provides a large surface for the crystallization of alumina, and the author found that the best method of addition involves precipitation of aluminum hydroxide from aluminum sulfate, using sodium hydroxide, followed by addition in the wet state to silica gel. In a later article Oborin (79) expresses the opinion, on the basis of thermodynamic calculations, that oxygen atoms cannot possibly constitute active centers, and the role of oxygen is solely that of ionizing the metal atoms. Active double centers are believed to be constituted in silica-alumina catalysts by two aluminum ions, whereas in silica-zirconia-alumina the double centers are constituted possibly by one aluminum and one zirconium ion. A thorough discussion of methods for evaluating cracking catalysts is given by Rescorla, Ottenweller, and Freeman (87). The authors describe surface area measurements including potassium hydroxide adsorption, nitrogen adsorption, and aromatic adsorption, the adsorption data being roughly indicative of catalytic activity. The methods of actual measurement of catalyst activity as practiced in differentlaboratories are given. The authors also describe the methods for the determination of impurities in natural and synthetic catalysts. Mills (67)describes a method for predicting the activity of cracking catalysts from the determination of the heat of wetting. Excellent agreement is shown between the results of determining the heat of wetting of catalyst by methanol and actual activity measurements. The method is applicable to partially carbonized catalysts, but free water causes a decrease in heat of wetting, while water present as a hydrate oauses a high value. Some complications are encountered with contaminated catalysts.
1917
Davidson (30)gives results obtained on cracking sulfur stocks with natural catalysts. He points out that the natural catalyst undergoes sulfur poisoning due to simultaneous dehydration of the catalyst. Exposure to dry hydrogen sulfide produces severe poisoning, whereas in the presence of hydrogen sulfide saturated with water a t 200" F., the deactivation is slight. Dehydration factors and commercial application are thoroughly discussed. Mills (68) discusses the "abnormal aging" of cracking catalysts as evidenced by loss of ability to produce gasoline relative to coke and gas. The effect of metal contaminants is very pronounced in reducing the gasoline production, and even minute amounts of iron, nickel, vanadium, and copper are detrimental. These poisons are contained in the petroleum stocks and accumulate on the catalyst. I n line with the work of Davidson (80), Mills reports a loss of activity of natural catalysts due to the presence of iron which is made catalytically active and, therefore, detrimental; the sulfur compounds in the stock are the activating agents. INDUSTRIAL FEATURES
Dart and Oblad (28) determined the heats of cracking of an East Texas gas oil over a synthetic bead catalyst, using the difference between the heats of combustion of charge and products. They employed precision calorimetry for the measurement of the heats of combustion of the charge and synthetic crude, while those of the gas and catalyst deposit were computed. The endothermic heat of cracking varied from about 300 B.t.u. per pound of cracked product a t 30% conversion to 50 B.t.u. per pound at 80% conversion. The regeneration characteristics of pelleted clay cracking catalysts were studied by Kirkbride and associates (19),who found the instantaneous burning rate to be proportional to the partial pressure of oxygen and the square of the carbon concentration a t a given temperature. Specific burning rates obtained at temperatures ranging from 900' to 110OO F. indicated an energy of activation of 26,600 calories per gram mole. They found that specific burning rates were not affected by gas linear velocities over the range of 6 to 40 feet per second. Richardson, Johnson, and Robbins (90) give comparison of silica-magnesia, silica-alumina, and natural clay catalysts based on their performance in a 100 barrel-per-day pilot plant. The silica-magnesia catalyst was found to be superior t o the other two with respect to gasoline yield. At 8 conversion of 60%, the silicamagnesia catalyst gave the highest gasoline yield with the lowest octane number; the silica-alumina gave the lowest gasoline yield with the highest octane number; the gasoline yields and octane numbers from the clay were intermediate between those from the synthetic catalysts. The silica-magnesia catalyst proved to be superior to silica-alumina from the standpoint of catalyst activity maintenance. In general, the authors indicate that the use of silica-magnesia catalyst is warranted in cases where high liquid yields are desired, and where yields of light unsaturated hydrocarbons are not of importance. High concentrations of sulfur in catalytic cracking feed stocks have been found to cause rapid deactivation and loss of selectivity of natural clay catalysts. However, if the catalyst is continuously steamed a t proper points in the circulating system, these degrading effects of sulfur can be minimized. Conn and Brackin (47) report on the benefits of adding steam to the regenerated catalyst before it contacts oil. They indicate that dispersion steam (fed with the oil) has some beneficialeffect in retarding SUIfur poisoning, and that the use of intensive steam stripping of spent catalyst will rejuvenate sulfur-poisoned catalyst. Mills (66) has offered the hypothevis that the loss of selectivity as applied to clay catalysts is due to the iron, naturally present, being brought into active form by its combination with sulfur in the reactor. During regeneration the iron sulfide is converted to a harmful, active iron oxide. However, water vapor is said to hinder the combination of sulfur compounds with the iron in clay
1918
INDUSTRIAL AND ENGINEERING CHEMISTRY
catalysts, and in this way the beneficial effects of prehydrstion are accounted for. Kerosene has been cracked at 525" to 575" C. over activated bauxite, activated alumina, and alumina impregnated with compounds of magnesium, boron, silicon, and fluorine, as reported by Stowc, Marshal, Nickel, and Greenwood (90). Iron compounds in natural bauxite were found to be deleterious because they promoted the formation of carbon and gas, and retarded the formation of aromatics. Among the impregnated aluminas, best results were obtained with a preparation containing about 3% silica. The investigators madc the unfortunate choice of using kerosene as a feed stock for their tests, which make interpretation rather difficult. A certain amount of small scale work has been reported by Leva and associates (69-61) and Wilhelm (108) on the fundamentals of fluidization of fine solid particles. Correlations have been developed to permit the estimation of the fluid rate a t which bed expansion begins. However, there has not yet appeared in the literature a generalized correlation which will cnable the prediction of fluidized bed densities irom the physical characteristics of the fluid and solid, and the rate of flow of the fluid. During the past year, the Thermofor catalytic cracking process has been modified and n a n d Houdriflow (3,3, 8, 10, ZB, 102). 8pecific design changes which have resulted in the new system are: replacement of the mechanical catalyst elevators with a gas lift for the vertical transportation of catalyst, elimination or reduction in size of the vapor charge superheater, reduction in size of the kiln and its cooling coils, and placing the reactor directly above the kiln in one integral vessel. By superimposing the reactor directly above the regenerator it is necessary to lift the catalysi, only once to complete a cycle of flow through the system. Economic comparisons are presented for five design cases, among which the principal variation is in the catalyst-oil ratio. The most favorable case is shown to be the one best described as a heatbalanced operation in which no feed preheater is employed, no steam is generated in the kiln, and the catalyst-oil ratio is a t the highest level of 7.3. Confronted with drastic decreases in residual fuel oil prices during the past year, the petroleum industry is finding its stocks of these fuels in storage rising sharply. Consideration of the ecunomics of various refinery processing schemes has led to the conclusion that catalytic cracliing is the best available tool for bringing the production of residual fuel oil into balance, and that a t market conditions prevalent in the spring of 1949 coking or viscosity breaking is the best method of preparing catalytic cracking feed stocks (51). Kimball and Scott (68) present a detailed comparison, based on a particular refiner's experience, of operating costs of fluid, Thermofor, and Houdry catalytic cracking processes along with those for conventional thermal cracking. These authors conclude that the cost of operating thermal cracking is lower than that of any of the catalytic processes. Pfarr (85),on the other hand, presents a comparison of thermal and catalytic cracking operating costs in a small refinery, and concludes that the cost per barrel of charge to the catalytic process is less than that for the thermal method. Purvin (85) has reviewed the conimercial operation of suspensoid catalytic cracking as practiced during the past eight years, and has considered the economics of converting thermal cracking equipment to suspensoid cracking in small refineries. A correlation of Thermofor catalytic cracking pilot plant data has been presented by Bednars, Luntz, and Bland (80) to show the effects of reactor temperature, space velocity, and catalyst activity on product distribution when a mid-continent gas oil is cracked over clay catalysts. These authors conclude that maximum gasoline yields are realized with a combination of high catalyst activity, low temperatures, and low space velocity. However, an increase in reactor temperature was shown to improve gasoline octane numbers.
Vol. 41, No. 9
A method of varying and controlling space velocity in reactors of the moving bed type by a mechanical arrangement which provides for varying the height of the catalyst bed by use of externally operated telescoping catalyst feed pipes is credited to S i m p aon ( 7 ) . The development of catalytic cracking processes has been used by Nelson (71) as an example of a complex solution to a complex refining problem, followed by simpler solutions as the problem was further investigated. The history of fluid catalytic cracking plant design was out'lined by flow diagrams, showing the evolution of a simplified design from its more complex predecessors. Read (86) presents experimental results for pilot plant re-forming of Pennsylvania naphthas, and for thermal and catalytic cracking of gas oils from the same source. It i s shown how replacing thermal cracking by catalytic cracking in a typical refining scheme will improve both the yield and octane rating of the total gasoline, and a t the same time minimize the production of residual fuel oil. Yields and octane numbers of gasolines produced by various combinations of thermal and catalytic cracking of Pennsyivania crude oil fractions have been presented by No11 and Luntz (75). A record-breaking run of 610.5 days of continuous operation was established by the Tide Water Associated Oil Company with its fluid catalytic cracking unit, a t Avon, Calif. ( 6 ) . Tne processing of heavy va,cuum distillates from California crudes over natural clay catalyst io this unit is described by W a n d and Seth (104),who report an interesting test in which the normal level of dense phase catalyst was dropped from the reactor into the stripping section. A ieduct'ion in coke yield and an improvement in liquid product yields were noted. This improvement in product distribut,ion was attributed in part to tne elimination of catalyst circulation between the cracking and stripping sections of the unit. It was reported that losses of catalyst fines from the Cottrell stack were reduced markedly, and that catalyst circulation was improved by raising the fines (less than 20 microns) content of the catalyst in the unit from 5% t o about 20% by the use of a he-grind Filtrol as make-up catalyst. I n the design of two fluid catalytic cracking units of the balanced pressure type (9, 106) the reactor and regenerator are placed side by side a t t,he same elevation. Other features which make these units different from earlier designs are the use of an external spent catalyst stripper and a cylindrical pressure type of electrical precipitator, and the inclusion of the slurry settler in the base of the main fract'ionator. The modernization of one of the original Thermofor catalytic cracking units, described by Hoge and Tiernan (60), includes the addition of two burning zmes to the kiln, and conversion of the reactor to concurrent flow by the installation of a cup type vaporcatalyst tiisengager. These changes are claimed t o permit operat,ion a t higher reactor temperature8 and higher conversions, prcducing greater quantities of gasoline having higher octane numbers. After its initial 176-day run using microspherical catalyst the inspecti0.n of the first simplified single-vessel fluid catalytic cracking unit showed negligible erosion of critical parts such as cyclones, slide valves, slurry pumps, and vessels according to Foster (96). Only 4500 man-hours were required for the 10-day turnaround. After the second run of 324 days on stream, this unit was shut down for only 79 hours for inspection. During this second run, for which the average feed rate was 4340 barrels per day, the catalyst, replacement amounted to only 0.207 pound per barrel of feed, according to Fisher (94). The design and early operat,ions of a small postwar Thermofor catalytic craclcing unit were presented by Kelso, Peavy, Myers, and Eoge (56), along with typical product yields from oncethrough and recycle operations on two Michigan gas oils. The first turnaround for this unit required 4557 man-hours after an initial run of 222 days (4). Carney, Noll, and Hoge ( 2 4 ) have described the processing of
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
September 1949
a n Arkansas gas oil containing 1.7% sulfur in a Thermofor catalytic cracking unit using synthetic bead catalyst. A gasoline containing 0.1% sulfur is obtained from this operation after caustic washing. It was reported that in this operation, 65'% of the sulfur in the feed appears in gas streams, 42% in the cycle stock, and about 3% in the gasoline. The sulfur content of catalytically cracked gasolines was shown by Sterba (97) t o be determined largely by the sulfur content of the feed stock and its source, and to a smaller extent by reaction temperature, conversion, gasoline end point, and catalyst type. A fluid catalytic cracking pilot plant having a nominal capacity of 3 barrels per day was described by Trainer, Alexander, and Kunreuther (101) as being useful for piloting commercial operations and for the study of process variables related t o the cracking and regeneration reactions. The flow diagram, plot plan, and several mechanical details are shown. Kelso and Snyder (66) describe a pilot plant which can be adapted to research investigations of either thermal or fixed bed catalytic conversions of hydrocarbons. A pilot plant having a nominal capacity of 3 gallons per hour, described by Flanagan (%), can be used t o predict yields and product quality for suspensoid catalytic cracking. I n an extensive summary Sittig (96) has reviewed recent technological advances in catalysts, kinetics, thermodynamics, fluid mechanics, and chemistry as applied to the various catalytic cracking processes.
CATALYTIC RE-FORMING CHEMICAL CONCEPTS
A considerable amount of work has been reported on various aspects of dehydrogenation of naphthenes as well as cyclization of parafEns. Herington and Rideal (48) investigated the kinetics of the dehydrogenation of cyclohexane and methylcyclohexane using a chromia-alumina catalyst. The authors show that the loss of the first pair of hydrogen atoms is the slow step in the reaction, the activation energy of this step being 36 kg.-cal. per gram-mole. In a later article ( 4 9 ) the same authors report the results obtained on competitive dehydrogenation of two naphthenes, a naphthene and a cyclic mono-olefin, and two cyclic mono-olefins. It is shown that either the groups of active sites on the catalyst surface are widely separated or any set of active sites is available for the reaction of any available naphthene. Thus there is no interference between naphthene molecules adsorbed on adjacent sites. When different mixtures of cyclohexene and trans-1,4dimethylcyclohexane are permitted to compete for the surface, the same extent of dehydrogenation is obtained for each compound regardless of concentration, which indicates that a naphthene and a cyclic mono-olefin can be dehydrogenated on the same active sites. Balandin ( l a ) has calculated the thermodynamic properties of adsorption complexes in dehydrogenation of naphthenic hydrocarbons using platinum, palladium, and nickel catalysts. These calculations show that a higher temperature favors the displacement of hydrogen by methylcyclohexane in a system involving methylcyclohexane, toluene, and hydrogen on a nickel catalyst surface. Balandin and Isagulyants (19) have determined the adsorption coefficients of naphthenes and aromatics relative to hydrogen. It was shown that the naphthenes are more readily adsorbed by the active sites than the products of dehydrogenation. The adsorption coefficients increase with the number of methyl groups attached t o the cyclohexane ring. I n a later article (14) the authors calculate the rate of dehydrogenation for a number of naphthenic hydrocarbons using the adsorption coefficients and feed rates of the naphthene and aromatic along with dimensions of the reaction tube. Obolenstev and Usov (77) studied the aromatization of paraffinic and olefinic compounds over a chromia catalyst a t 480' C. n-Heptane a t 0.5 liquid hourly space velocity gave about 13%
1919
aromatics as compared to 6 % from 2,2,4trimethylpentane, while 1-heptene produced 45% aromatics, 2-methyl-2-hexene 30%, and 3-methyl-3-heptene 32q0. When mixtures of olefins and paraffin8 were processed over the same catalyst the yields of aromatics were additive. I n general, the olefins produced more coke. Further work on the cyclization of pure compounds has been reported by Nametkin, Khotimskaya, and Rozenberg (69) who processed butylbenaene and butylcyclohexane over a chromiaalumina catalyst a t 520' C. and 0.25 liquid hourly space velocity. Both compounds gave approximately 40% naphthalene, the other products being toluene, ethylbenzene, and propylbenzene; no benzene or xylenes were isolated in either case. No products of partial dehydrogenation were obtained, indicating that cyclization is accompanied by complete dehydrogenation. Balandin and Raik (16) have attempted to explain the mechanism of cyclization of substituted n-pentanes and gem-substituted n-hexanes t o produce aromatics. According t o the authors, both types of compounds form a five-membered ring followed by isomerization to a six-membered ring. This isomerization occurs in a specific manner, so that p-xylene is produced from 2,2,4trimethylpentane whereas 2,2-dimethylhexane yields mxylene. The actual results agreed with the postulate in seven examples; one example was widely divergent. The dehydrogenation of the isomers of 1,2,3-trimethylcyclohexene, l-ethyl-3-methylcyclohexene,and 2,Pdimethyl-1-cyclohexene waB studied by Reynolds, Ebersole, Lamberti, Chanan, and Ordin (88). The authors employed a commercial chromiaalumina catalyst at 450" t o 470" C. and obtained the corresponding aromatics in yields of 7 9 , 8 2 , and 88%, respectively. I n later work by KazanskiI, Liberman, and Batuev (54),i t was shown in processing 3,3-dimethylhexane at 290" to 300" C. over platinized carbon that 1,1-dimethylcyclohexane is one of the products of reaction. This provides some substantiation t o the postulate that the aromatization proceeds through the formation of the gem-substituted cyclohexane. The naphthene itself was dehydrogenated in earlier work (69) to produce primarily toluene and 0- and rn-xylenes. No ring opening was observed to take place. Considerable additional work with platinum containing catalysts has been reported, Pines, Olberg, and Ipatieff (84) dehydrogenated pinane and p-menthane in the presence of platinum alumina, platinum pumice, and platinum charcoal catalysts a t 240' and 300' C. The authors found that pinane produces 1,2,4 and 1,2,3-trimethylbenzenes in addition to the previously reported pand o-cymene. p-Menthane yields p-cymene with conversions of 95 to 100% at 300" C. in the absence of a solvent or in the presence of pentane or benzene. The use of pentene as a solvent does not interfere with the dehydrogenation reaction at 1 t o 1 ratio of pentene t o p-menthane; however, a t a 4 to 1 ratio the dehydrogenation is reduced to 8%. A deactivating effect of some olefins was also observed by Shuikin, Novikov, and Tulupova (QC),who dehydrogenated mixtures of a narrow cut of a previously dearomatized gasoline with unsaturated hydrocarbons in the presence of a 5% platinum on activated carbon catalyst. The ratio of gasoline t o the unsaturated hydrocarbon was 10 t o 1 and the experiments were carried out at 300" to 305" C. and about 0.5 space velocity. The deactivating effect was characterized by the ability of the catalyst to dehydrogenate cyclohexane before, during, and after the experiments with the mixtures, There was only a very slight inactivating effect of 1-octene, 1-heptene, and 1-hexene, whereas l-ethyl-lcyclopentene lowered the catalyst activity to about one half of its original value. When this compound was processed alone the activity of the catalyst was reduced to about 15% of the original. Allylcyclopentane and cyclopentadiene also caused a lowering in catalyst activity. According to Novikov, Rubinstein, and Shuikin (76) there is practically no change in the crystal lattice or grain size of the platinum in a 20% platinum on activated carbon catalyst, when the latter is subjected to prolonged heat treatment a t 300" C.
1920
INDUSTRIAL AND ENGINEERING CHEMISTRY
A catalyst of the above-mentioned composition was heat-treated for 639 hours a t 300" C. followed by dehydrogenation of cyclohexane for 120 hours a t the same temperature, followed by regeneration a t temperatures well above 300" C. The crystal size was not changed by this treatment, whereas in the absence of a carrier platinum undergoes recrystallization a t much lower teniperatures. The authors conclude that on a carrier the platinum grains are localized and isolated from one another. The dehydrogenation of tetrahydronaphthalene and other liydrogenated aromatics was investigated by Shishido and Nozaki (93). The procedure used involved the addition of iodine in small portions to the heated compounds; the products were the corresponding aromatics. A secondary reaction of condensation was also observed. The conversion of dicyclohexyl t o diphenyl using benzene as a hydrogen acceptor was investigated by Adlrins, Rae, Davis, Hager, and Hoyle (I), who found that in the presence of a nickel catalyst a t 350" C. in a steel reaction vessel the yields of diphenyl varied from 1 to 90%. When benzene containing traces of thiophene was employed good yields of diphenyl were obtained. This led t o a thorough investigation of sulfur compounds as promoters for this type of dehydrogenation, and it was found that diphenyl sulfide was even more satisfactory than thiophene in promoting the nickel catalyst. Limiting amounts of sulfur compound were determined; the presence of l part of sulfur in 30 parts of reduced nickel appears to be optimum while 1 part in 20 shows a deactivating effect. The addition of small amounts of sulfur or nickel sulfide had a small promoting effect as compared to thiophene or diphenyl sulfide. This promoting effect was not observed with Raney nickel or platinum or palladium catalysts. A number of investigators have studied the structure and physical properties of re-forming catalysts. Thus, Eischens and Selwood (33)have correlated the activities of a number of chromiaalumina catalysts with magnetic susceptibilities. They point out that dispersion of the chromia is the underlying factor in producing a close relationship between activity and magnetic susceptibility. The postulate is made that chromia is scattered over the surface of the alumina in small piles about three atom layers thick. MaslyanskiI and Bursian (66) studied the effect of regeneration temperature of a chromia-alumina catalyst upon the ratio of chromium trioxide to chromic oxide and the activity for dehydrogenation of cyclohexane. The 20% Cr20a-80% A1203 catalyst was regenerated a t 450°, 550°, and 650" C. for 6 hours, following which the activity was increased from 20.8% conversion to benzene to 25.1 and 28.8%, respectively. The ratio of chromium trioxide to chromic oxide after regeneration a t 500" C. was 0.078, whereas after regeneration a t 600 O C. it was 0.092. The effect of a higher regeneration temperature is retained even after reduction, as indicated by a higher activity of such a catalyst. Russell and Stokes (91)investigated the heat stability of molybdena-alumina dehydrocyclization catalysts. The dehydrocyclization of n-heptane t o toluene is increased as the catalysts are calcined a t temperatures from 600" to 700' C., while a t higher calcination temperatures the activity is lowered. A more uniform distribution of molybdena on alumina is believed t o be responsible, at least in part, for the increased activity attained with higher calcination temperatures. The stability of the composite decreases with increasing amounts of molybdena. The activity increases with added molybdena up to the formation of the monolayer on alumina, and there appears t o be no advantage in using larger amounts. When molybdena is present in an insufficient amount for the monolayer, the catalyst will maintain its activity with loss in area until sufficient area remains for the monolayer. This indicates that molybdena either can rediffuse to the surface, or is not covered up during the loss of area. INDUSTRIAL FEATURES
A new catalytic re-forming process called PIatforming was announced by Nelson of Universal Oil Products Company (70, %?).
Vol. 41, No. 9
As a method of improving straight-run gasolines, it combines the desirable features of large octane number gains, low volunietric losses, good desulfurization, and moderate plant and operating costs. The yield-octane number relationships for Platforming are compared with those for thermal re-forming, polyforming, and hydroforming of a mid-continent naphtha to produce a rc-formate having a clear motor method octane number of 75. Typicai yields and product properties are also given for Platforming of a variety of virgin naphthas and gasolines. At yields in excess of 90% the re-formates have clear F-2 octane numbers of 76 or more, and clear F-1 octane numbers of 81 to 85. The lead response is such that 10 to 12 octane number gains are obtained by the addition of 3 ml. of tetraethyllead per gallon. About 90% desulfurization was realized. The catalyst is of such nature, and operating conditions are so chosen that a proper balance among aromatization, hydrocracking, and isomerization reactions is obtained, while a t the same time carbon formation is suppressed to the extent that catalyst regeneration is not required. Although a flow diagram is not shown, the plant involves a preheating and reactor section, a recycle gas compressor, and conventional fractionation for feed preparation and product recovery. The successful application of the fluid catalyst technique to hydroforming requires that the alternate oxidation and reduction of the conventional molybdena-alumina catalysts be minimized or eliminated. I t has been claimed that by the inclusion of calcium oxide in the conventional catalyst in approximately 1 to 1 mole ratio of calcium to molybdenum, the alternate oxidation and reduction of the catalyst are essentially eliminated (38). Although all hydroforming units operated during the iecent war were basically similar, the unit a t the refinery of Standard Oil Company of California differed from the others in that its reactors were designed with ten multiple shallow beds arranged so that the vapor flow was in parallel through the beds (23). Thii design was employed to minimize pressure drop and cost of circulating regeneration gases. The selection of a molybdena-alumina gel type catalyst prepared by coprecipitation of the components was based on its superiority over other preparations becairsc. of its better stability a t high temperaturos and its activity for the production of toluene from C? naphthenes. It was stated that the plant has operated for more than two yeais on a single charge of catalyst of this type, In most other cases toluene was separated from the hydroformer effluent by extractive distillation or solvent extraction; however, this unit prepared ni tration-gr ade toluene by producing a toluene cut of 90% purity, recycling unchanged feed to extinction. This toluene concentrate was then passed through the unit again in blocked-out operation, and suhsequently acid-treated to produce nitration-grade toluene. biclaurin, McIntosh, and Knufman (62) present data on hydroforming and thermal re-forming of sweet and sour naphthas. Hydroforming shows a definite yield-octane number advantage over thermal re-forming, but up to 78 motor method octane numbers thermal re-forming was slightly more economical when only direct operating costs were computed for the two processes. Helmers and Brooner (46)have presented data for the re-folming of cracked and straight-run gasolines over bauxite catalgst, showing yields and product quality. A hydroforming pilot plant described by Yule and Bennett (109)has been operated as an aid in the study of various problem arising in conimercial operation, and to study fundamentals of the hydroforming process. It is shown that yield-octane number relationships from the pilot unit are in close agreement with cornmercial results.
DEHYDROGENATION CHEMICAL CONCEPTS
A substantial amount of work has been reported 011 the d e b drogenation of hydrocarbons. A good part of the effort has been devoted t o the conversion of alkylbenzenes, particularly ethylbenzene, t o the corresponding alkenylbenzenes.
September 1949
INDUSTRIAL A N D
ENGINEERING
Nickels, Webb, Heintzelman, and Corson (74) report the dehydrogenation of isopropylbenzene t o a-methylstyrene in the presence and absence of catalysts. A magnesium-iron-potassiumcopper oxide (72.4 t o 18.4 t o 4.6 t o 4.6) was found t o give the highest ultimate yield (84%) of the desired product at 600' C., 0.5 liquid hourly space velocity, and in the presence of 10 moles of steam per mole of isopropylbenzene. The conversion per pass was about 25%. I n the absence of catalysts a higher temperature was required to give the desired conversion per pass; however, the selectivity was impaired by temperatures in excess of 600' C. Balandin and Marukyan (16)investigated the dehydrogenation of polyethylbenzenes and found that the alkyl chains in mono-, di-, and trisubstituted benzenes are dehydrogenated a t the same rate. They conclude that in polyalkylbenzenes the dehydrogenation of all substituents occurs simultaneously. I n another study, Balandin and Tolstopyatova (17') investigated the relative adsorbabilities of ethylbenzene in admixture with styrene, toluene, and benzene in dehydrogenation, They found that styrene can displace ethylbenzene from the active centers, while ethylbenzene can displace toluene and benzene. The link between ethylbenzene and the catalyst surface is mainly through the alkyl group. Ghosh, Guha, and Roy (3.9) studied the dehydrogenation of ethylbenzene to styrene in the presence of the following catalysts: (85-15), Crs03-AlqOa-ZnO (25-25-50), Cr~Oa-A1~08iGr~Os-Al~Os FelOl (SO-5-15), and Crs03-AI20a-Cu (70-15-15). They calculated the equilibrium constants a t 480' to 600' C. using the equation K p =
U2 (p/760) where u is thedegree of dissooiation 1 - up
of ethylbenzene and p is the reaction pressure in millimeters of mercury. INDUSTRIAL FEATURES
I)
Rates of the primary and secondary reaction, both thermal and catalytic, for the dehydrogenation of n-butenes to butadiene in the presence of steam over catalyst 1707 were established by Beckberger and Watson (19) using small pilot plant equipment. Their analysis of the data obtained suggests that the kinetics of the primary dehydrogenation reaction corresponds to a mechanism which assumes the reaction of an adsorbed n-butene molecule with an adjacent vacant active center. By the integration of individual rate equations the authors obtained results which were claimed t o be in close agreement with the performance of commercial scale reactors. The pilot plant operated t o verify the practicability of butene dehydrogenation over catalyst 1707 to produce butadiene and to guide the operation of commercial unita has been described by Nicholson, Moise, and Segura (79). Having a nominal capacity of 10 tons per day of product, this plant provided information regarding catalyst life and handling, mechanical design of mixing nozzles, and operating procedures. Hackmuth and Hanson (49)report pilot plant investigations of the dehydrogenation of n-butane t o butylenes over several chromia-alumina catalysts. In addition t o studying the effects of the usual process variables on the dehydrogenation reaction and catalyst stability, they report the effects of variations of oxygen and water concentrations in the regeneration gas on the behavior of the catalyst during the processing period. A commercial installation of the Phillips butane dehydrogenation process for the production of butenes over pelleted chromiaalumina catalyst is described by Hanson and Hays (46). Improvements over initial operations were realized by the adoption of a higher chromia content catalyst, and by the replacement of 27 chrome steel (Type 446)reactor tubes with Type 310. A catalyst life of over 100 days was claimed, Whereas the ultimate yield of butenes was about 72% for the original catalyst, an ultimate yield of 80% was realized with the higher chromia content catalyst a t an equivalent age of 100 days. The dehydrogenation of ethylbenzene was studied by Wenner and Dybdal (107) in laboratory and pilot plant equipment, using
CHEMISTRY
1921
in one case a catalyst requiring periodic regeneration, and in another case a catalyst which was self-regenerating in the presence of substantial amounts of process steam. These data were correlated from a kinetic and thermodynamic standpoint in order to permit the analysis of various problems concerned with the design of commercial reactors.
LITERATURE ClTEQ (1) Adliins, H., Rae, D. S., Davis, J. W., Hager, G. F., and Hoyle K., J . Am. Chem. SOC.,70,381 (1948). ( 2 ) Anon., Oil Gas J.,37, No. 37, 78 (1949). (3) Anon., Petroleum Engr., 21, No. 1, 23 (1949). (4) Anon., Petroluem Processing, 3, 111 (1948). (5) Ihid., 3, 216 (1948). (6) Ibid., 3,719 (1948). (7) Ibid., 3,998 (1948). ( 8 ) Ibid., 4, 137 (1949). (9) Anon., Petroleum Refiner, 27, No. 5, 121 (1948). (10) Ihid., 28, No. 1, 110 (1949). (11) Ibid., 28, No. 4, 120 (1949). 63, 33 (1948). (12) Balandin, A. A., Doklady Akad. N a u k S.S.S.R., (13) Balandin, A. A., and Isagulyants, G. V., Ihid., 63, 139 (1948). (14) Ibid., 63, 261 (1948). (15) Balandin, A. A., and Marukyan, G. M., Izvest. Akad. N a u k
S.S.S.R., 1948, 461.
(16) Balandin, A. A., and Raik, S. E., Cornpt. rend. acad. sei. U.R.S.S.,56, 161 (1947). (17) Balandin, A. A., and Tolstopyatova, A. A., J . Gen. Chem. (U.S.S.R.), 18, 865 (1948). (18) Barron, J. M., Vander Ploeg, A. R., and McReynolds, H., 115th Symposium on Organic Sulfur Compounds, Division of Petrolevm Chemistry, 115th Meeting, AM. CHEM.Soc., San Francisco, Calif., 1949. (19) Beckberger, L. H., and Watson, K. M., Chem. Eng. Progress, 44, 229 (1948). (20) Bednars, C., Lunta, D. M., and Bland, R. E., Ibid., 44, 293 (1948). (21) Bitepaah, Yu. A., J . Gen. C h a . (U.S.S.R.), 17,199-207 (1947). (22) Burtis, T. A,, Dart, J. C., Kirkbride, C. Cr., and Peavy, C . C., Chem. Eng. Progress, 45, 96 (1949). Burton, A. A., Chiswell, E. B., Clausen, W. H., Huey, C. S., and Senger, J. F., Ibid., 44, 195 (1948). Carney, W., Noll, H. D., and Hoge, A. W., Petroleum Refiner, 27, No. 12,625 (1948). Chaney, N. K., Hall, E. L., Skeen, J. R., and Smoker, E. H., Chem. Eng. Progress, 45, 71 (1949). Ciapetta, F. G., Macuga, S. J., and Leum, L. N., Im. ENQ. CHEM.,40, 2091 (1948). Conn, A. L., and Braokin, C . W., Symposium on Modern
Motor Fuels, Division of Petroleum Chemistry, 113th Meeting, AM. CHEM.SOC., Chioago, Ill., 1948. Dart, J. C . , and Ohlad, A. G., Chem. Eng. Progress, 45, 110 (1949).
Dart, J. C., Savage, R. T., and Kirkbride, C. G., Ibid., 45, 102 (1949).
Davidson, R.C., Petroleum Refiner, 26, No. 9, 663 (1947). Dazeley, G . H., and Hall, C. C., Fuel, 27, 50 (1948). Eastwood, 8. C., and Potas, A. E., Petroleum Processing, 3, 837 (1948).
Eisohens, R. P., and Selwood, P. W., J . Am. Chem. isoc., 70, 2271 (1948). Fisher, M. M., Oil Gas J., 47, No. 37,52 (1949). Flanagan, J. W., IND.ENG.CHEM.,41, 211 (1949). Foster, A. L., Oil Gas J., 46, No. 46, 101 (1948). Funasaka, Wataru, and Horikawa, Kihachiyo, J . SOC.Chem. I n d . Japan, 47,160-2 (1944).
Gaylor, P. J., Petroleum Processing, 3, 1218 (1948). Ghosh. J. C., Guha, 8. R. D., and Roy, A. N., Petroleum, 10, 236 (1947).
Goldtrap, W. A., and Jones, E. L., Petroleum Engr., 20, 269 (1948).
Gordon, A. S., J . Am. Chem. SOC.,70,395 (1948). Grenall, Alexander, IND.ENQ.CHEM.,40,2148 (1948). Hackmuth, K., and Hanson, G. H., Chem. Eng. Proogress, 44, 421 (1948).
Haensel, V., and Sterba, M . J.,
I N D . ENQ. &EM., 40, 1660 (1948). Hanson, G. H., and Hays, H. L., Chem. Eng. Progress, 44, 431 (1948). Helmers, C. J., and Brooner, G. M., Petroleum Processino, 3, 133 (1948). Hepp, H. J., and Frey, F. E . , IND.ENQ.CREM.,41, 827 (1949). Herington, E. F. G., and Rideal, E. K., Proc. Roy. SOC.,A190, 289 (1947).
INDUSTRIAL AND ENGINEERING CHEMISTRY Ibid., A190,309 (1947). Hoge, A. W., and Tiernan, W., Petroleum Engr., 21, No. 4, 7
Offutt, W. C., Fogle, M. C., and Beuther, H., Petroleum Processing, 3, 1083 (1948).
(1949).
Parravano, G., Hammel, E. F., and Taylor, H. S., J. Am.
Hornadav, G. F., Noll, H. D., Peavy, C. C., and Weinrich,
Chem. SOC.,70, 2269 (1948).
W., Oil Cas J . , 47, No. 49, 90 (1949).
Partington, R. G., and Danby, C. J., J . Chem. SOC.,1948,
Ipatieff, V. N., and Schmerling, L. S., IND.ENO. CHEM.,
2226.
40, 2354 (1948).
Pfarr, J. S.,Petroleum Procesaing, 3, 666 (1948). Pines, H., Olberg, R. C., and Ipatieff, V. N., J . Am. Chem. SOC.,70, 536 (1948). Purvin, R. L., WorldPetrolezcm, 19, No. 4, 69 (1948). Read, Davis, Jr.. Petroleum Processing, 3, 329 (1948). Rescoria, A. R., Ottenweller, J. H., and Freeman, R. S., Anal. Chem., 20, 196 (1948). Reynolds, T. W., Ebersole, E. R.,Lamberti, J. M., Chanan, H. H., and Ordin, P. M.,IND.ENG.CHEM.,40, 1751 (1948). Rice, F. O., and Haynes, W. S.,J . A m . Chem. Soc., 70, 964
Kazanslai. 33. A., and Liberman, A. L., Bull. Acad. Sci. U.R.S.S., 1947,265.
Kazanskii, B. A., Liberman, A. L., and Batuev, M.I., Dokladi/ Akad. Naub S.S.S.R., 61, 67 (1948). Kelso, E. A., and Snyder, 5. A., IND. ENG.CHEM.,40, 1332 (1948).
Kelso, G., Peavy, C. C., Myers, G. D., and Hoge, -4.W., Petroleum Refiner, 20, No. 1,293 (1948).
Xeinball, C., and Taylor, H. S.,J . Am. Chem. Soc., 70, 345 (1948).
(1948).
Kimball, T. B., and Scott, J. A., Petroleum Refiner, 27, No. 6,
Richardson, R. W., Johnson, F. B., and Robbina, L. V., Symposium on LModern Motor Fuels, Division of Petroleum Chemistry, 113th Meeting, AM. CHEM.SOC., Chicago, Ill. Russell, A . S., and Stokes, J. J., Jr., IND. EXG.CHEM.,40, 520
326 (1948).
Leva, M., Grummer, M., Weintraub, M., and Pollchik, M., Chem. Eng. Progress, 44, 511 (1948). Ibid., 44, 619 (1948). Leva, M., Grunimer, M., Weintraub, M., and Storch, H. H., lbid., 44, 707 (1948). McLaurin, N. H., McIntosh, C. H., and Kaufman, 19. S., PetroEeum Refiner, 28, No. 4, 171 (1949). McReynolds, H., andBarron, J.M., Ibid., 28, No. 4, 111 (1949). Madorsky, S. L., and Strauss, S., TND. ENG. CHEM., 40,
(I 948).
Seymour, R. B., Ibid., 40, 524 (1948). Shishido, Keiichi, and Nozaki, Hajime, J. SOC.Chem. I n d . J a p a n , 47, 819 (1944).
Shuikin, N. I., Novikov, S. S., and Tulupova, E. D., Bull. Acad. Sci. V.R.S.S., 1947, 89.
Sittig, Marshall, Petroleum Processing, 4, 274 (1949). Smith, L. I., and Lo, Chien-Pen, J . Am. Chem. Sac., 70, 2209
848 (1948).
Maslyanskii, G. PIT., and Bursian, N. R., J . Gen. Chem.
(1948).
(U.S.S.K.), 17, 208 (1947). Mills, G. A,, presented before Symposium on Organic Sulfur Compounds, Division of Petroleum Chemistry, 115th
Sterba, M. J., Symposium on Organic Sulfur Compounds, Diviion of Pctroleuni Chemistry, 115th Meeting, AM. CHEM.SOC., San Francisco, Calif., 1949. Stevenson, D. E., Wagner, C. D., Beek, O., and Otvos, J. W.,
hleeting, Abf. CHEM.SOC. San Francisco, Calif., 1949. Mills, I. W., Oil Gas J . , 48, No. 28, 237 (1947). Morton, Maurice, and Nicholls, R. V. V., Can. J. Research, 26B,581-91 (1948). Nametkin, S. S., Khotimskaya, M. I., and Rozenberg, L. M., Bull Acad. Sei. U.R.S.S., 1947, 705. Nelson, E. F., Oil Gas J.,47, No. 49, 95 (1949). Ibid., 47, No. 50, 108 (1949). Nelson, E. F., Petroleum Engineer, 21, No. 4, C-22 (1949). Nicholson, E W., Moise, J. E., and Segura, M. A., IND. ENG.
J . Chsm. Phus., 16, 993 (1948).
Stowe, V. M., Marshal, E. E., Nickel, L. L., and Greenwood, R. S., Petroleum Processing, 3, 317 (1948). Tighe, 11. F., Ibid.. 3, 986 (1948). Trainer, R. P., Alexander, N. W., and Xunreuthcr, F., INU. E N G . CHEM., 40,
4035 (1948).
Viland, C. K., and Seth, J., Oil Gas J..47, No. 3, 186 (1948). Voge, H. H., and Good, G. M., J. Am. Chem. Soc., 71, 593 (1949).
Weber, G. H., Oil Gas J . , 47, No. 36, 81 (1949). Wenner, R. R., and Dybdal, E. C., Ch,em. Eng. Progress, 44, 275 (1948).
Wilhelm, R. H., and Kwauk, M., Ibid., 44, 201 (1948). Yule, L. T., and Bennett, R. B., IND.ENG.CHEW,40, 1995
17, 897 (1947).
*
175 (1948).
Uhl, W. C., Petroleum Processing, 3, 1163 (1948). Vanas, D. W.,and Waiters, W. I?., J . -4.m. Chem. SOC.,708
C H E M . , 646 ~ ~ ,(1949). Nickels, J. E., Webb, G. A., Heintzelman, W., and Corson, B. B., Ibid., 41, 563 (1949). Noll, N. D., and Luntz, D. M., Oil Gas J . , 46, No. 37,81 (1948). Novikov, S.S., Rubinstein, A. M., and Shuikin, N. I., Dokladg Acad. N a u k S.S.S.R.. 62. 345 (1948). Obolenstev, R. D., and Usov, Yu: N., J . Gen. Chem. (U.S.S.R.),
Oborin, V. I., Neftgunoe Khoz., 25, No. 11, 50-4 (19471. Oborin. V. I., Zhur. Obschel Khim. ( J . Gen. Chem.), 18, 612 (1948).
Vol. 41, No. 9
(1948). RECEIVBD June 21, 1949.
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The early issues of I.&E C. (1910-20) rrflect the technical and personality struggles of petroleum refiners and chemists to cope with the problem of “a waning supply of gasoline,” created by an undiminishing use of petrolENG.CHEM.,5, 514 (1913)] t o provide more driven motors. Suggestions proposed by technical groups [J.IND. fuel for automobiles (at a reasonable price) included the use of alcohol or benzol, production of gasoline from kerosene or natural gas, and lowering the specific gravity of commercial gasoline. A year later [J. IND.ENG CHEM.,6, 688 (1914)], one worker was firmly convinced that a thorough series of petroleum dlstillations begun on a factory scale and carried out t o the highest limit of efficiency would richly reward the immense labor involved, but he keenly felt his helplessness in the enormity of such an undertaking. The trend toward modern refining was clear by 1915-for example, “Gasoline from Heavier Petroleums” [J. IXD.ENG.CHEW,7, 1029 (1915)l described production of gasoline by still and tube cracking under normal and high pressures and the applicability of the products as fuel for motor vehicles. I n 1917 only 20% of the 70,000,000 barrels of gasoline produced was from cracking operations, but the method was established as the basic solution to the gasoline shortage; it was estimated that by 1920 more gasoline would be produced by crackENG.CHEM.,9, 530 (1917)l. In a review of the progress of petroleum ing than by any other method [J. IND. refining [J. IND. E m . CHEBI.,10, 484 (1918)], W. M. Burton discussed the differences between refiners and chemists and told of the mutual educational program which had been necessary before the first stills could be constructed and operated successfully. He expressed the hope that chemlsts who had been trained in the technical work would do their bit for the chemistry of petroleum. Modern “cat” crackers (page 1916) and today’s gasoline production, averaging 2,500,000 barrels per day, are indicative of the full cooperation which has since been achieved between these groups.
