RECENT ADVANCES IN PETROLEUM
0
B. H. SHOEMAKER, E. L. drOUVILLE, and ROBERT F. MARSCHNER Standsrd Oil Company (Indiana), Whiting, Indiana
R E n N I N G of petroleum consists of making it into gasoline, heavier fuels, lubricants, and many other products. Gasolines and solvent naphthas roughly comprise the lower-boiling half of all refined petroleum. Heavier fuels for heating and diesel engines make up about one-quarter. Lubricants of many kinds represent nearly one-eighth. Lesser products like chemicals, waxes, asphalts, and coke together make up a little over one-sixteenth. Most of the remaining sixteenthis burned iu the refinery to provide the energy needed to process the rest. Thus, more than three-fourths of petroleum goes into fuels that are burned. Gasoline bums under exacting conditions and deserves by far the most researchfundamental as well as applied. The heavier fuels, burned in devices that are less demanding, require less attention. Naturally, the advances in petroleum refining sirice World War 11, hke those of the decade before, emphasize gasoline ($3). Products otherthanfuels have also been improved; recent advances in the fields of lubricants and petrochemicals are reviewed elsewhere
(46). COMPOSITION OF PETROLEUM
properties. Lastly, individual or combined streams are finished to meet the needs of consumers. These three steps--separation, conversion, and finishingpresent a convenient framework for discussing recent advances in petroleum refining. SEPARATION
Physical processes that separate petroleum usually involve two phases. One is always the liquid phase. I n distillation, the other is vapor; in extraction, it is liquid; and in crystallmation, it is solid. Many variations of these processe8 are possible, and all have heen improved and extended in recent years. One separation process that does not involve two phases is thermal diffusion; it has not yet been introduced into refineries, although pilot plants are running in several laboratories. Yesterday's research on composition of petroleum has led to today's refinery separations. Today's composition studies forecast separations that will be used tomorrow (18). A fnndamental picture of petroleum therefore helps to illustrate practical separation methods. Figure 1 gives such a picture. At left the number of carbons is plotted; because there are fewer hydrocarbons of each successive carbon number in petroleum, the scale is logarithmic. Along the bottom is plotted hydrogen-to-carbon ratio. I n the npperright corner is methane with one carbon and four hydrogens. Downward from the methane corner extend the alkanes toward a ratio of two. For all practical purposes, carbon can be considered to lie in the lower left corner. The condensed polycyclic aromatic hydrocarbons, or condenqed arenes, extend upward from near the carbon corner toward a ratio of one. Petroleurh has an average composition that is much nearer the alkanes than the arenes. Distillation separates ~-~~~~ it verticallv " bv " carbon number. and extraction separates it horizontally by H:C ratio. Crystallization and thermal diffusion separate it in a different way that involves the shape rather than size or composition of the molecules. ~
0
I
2
3
4
HYDROGEN: CARBON RATIO
rimreI
The first job of a refinery is to separate petroleum physically into a series of streams. Some closely resemble the final products, but others must next be converted by chemical change to reach the desired 'Presented a t a joint Symposium on "Recent Advances in Petroleum Chemistry" before the Divisions of Chemical Eduoiltion and Petroleum Chemistry at the 125th Meeting of the American Chemical Society, Kansas City, Mo., March, 1954.
Distillation
BY far the oldest a d most common separation Process is distillation. Although laboratory fractionation columns have taken many forms in the past 25 years, refinery fractionating to,,,ers are only beginning to depart from the bubble-tra~ design. One is that towers don't Tear out; if they outlive one use, 30
JANUARY, 1955
31
they are often put to another. The huge 100-tray boron fluoride and hydrogen fluoride is used, the comtowers built for the aviation gasoline and synthetic plexes formed with arenes and sulfur compounds are ~ b b e plants r of World War I1 represented the ultimate apparently salts of the nonexistent acid HBF4 (12). in bubble trays. Simpler trays and efficient packings Extraction is consequently more efficientthan mith the are being introduced ( I d ) . Greater capacity and physical solvents. better separations result; the towers are smaller and Adsorption, long used for decolorizing paraffin wax, cost less. somewhat resembles extraction. In the Arosorb process recently developed, arenes are separated from naphREFINERY STREAMS thas by silica gel (9). Arenes adsorb on the gel more I I I tightly than the alkanes; by flushing successively with butane and toluene, the alkanes are removed and ' the arenes are recovered. /'
-
Crystallization HEAVY NAPHTHAS NEROSENES DIESEL FUELS LU8RICANN FUELS I
2
3
HYDROGEN: CARBON RATIO
F i g " . .
2
Separation by distillation in refineries has slowly but steadily become sharper. Better packings and more trays eliminate bothersome "heads" and "tails" and increase quality or yield of desired products. Vacunmdistillation units have become standard equipment in the 50 refineries that make lubricating oils. Extraction
Dewaxing of lubrication oils is the classical example of crystallization in petroleum refining. The products are paraffin wax, which consists of n-alkanes, and microcrystalline wax, which may contain a branch or a ring. Crystallization methods have recently been applied to other hydrocarbons: naphthalene, paraxylene, and cyclohexane are now separated from petroleum streams by crystallization. An exciting discovery of the past decade was the urea-n-alkyls. The ability of urea to form insoluble crystalline complexes with straight-chain hydrocarbons has been thoroughly studied and may soon be used in refineries (24). Treatment of fuels mith urea separates waxes that cannot be removed in any other way. A deterrent to use in refining has been the large amount of urea required. Through these separations, petroleum is prepared for conversion and finishing. F~gure2 shows, on the same scale and with the same alkane and arene lines as before, the major streams produced. Distillation has sorted out successively highei60iling naphthas, kerosene, gas oil, lubricants, and residues. Extraction has removed hydrocarbons 7%-itha low H: C ratio and nonhydrocarbons from the naphtha and lubricant fractions. Also from the latter, crystallization has separated wax. But there is more gas oil than is needed for heating homes and for diesel fuel and not enough naphtha for gasoline. And everything except the residues will need further treatment before sale.
Extraction occurs when a petroleum fraction is mixed with a substance in which it is incompletely soluhle. Most substances extract hydrocarbons with the lowest H : C ratio but some do so far more efficiently than others. When the ratio is far apart, as in alkanes and arenes, separation is easy. Arenes are extracted from naphthas because they are desired as chemicals, and from higher-boilmg fractions because they are undesirable in lubricants. Compounds that contain oxygen, sulfur, and nitrogen are more soluble than hydrocarbons and accompany the arenes PETROLEUM-CONVERSION PROCESSES into the extract. Some solvents extract arenes by I , I I I ./*I purely physical action; others form loose chemical CRACKING 0complexes with them. 2 / / A physical solvent that has come into use recently rn Z / is diethylene glycol. I n the Udex process for removing arenes from naphthas, its solubility is regulated by the * / HYDROGENATION / addition of controlled amounts of water (20). The 0 L 10 - OEHYDROGENATION / search for new solvents for heavier fractions continues; 0 rn / ISOMERIZATION exotic solvents have received attention but have not g 2 0 / replaced sulfur dioxide and other conventional solvents. 5 / One solvent that, acts through complex formation Z so I I POLYME~IZATION is liquid hydrogen fluoride (23). Unlike sulfuric acid, I I I 1 1 I which it somewhat resembles in behavior, it can be 0 I 2 3 4 recovered by distillation. I t has not yet been used HYDROGEN: CARBON RATIO commercially because of the high cost of the corrosionI'i-3 resistant materials needed. When a combination of
-
32 CONVERSION
The earliest conversion process, cracking of gas oil t o naphtha, is still by far the most important; the major reaction is breaking of carbon-carbon bonds. Conversions introduced recently, aimed a t raising octane number, often involve carbon-hydrogen bonds. A convenient way of classing conversions again makes use of a plot of carbon number and H:C ratio, and is shown in Figure 3. Cracking and polymerization change the size of hydrocarbons with little effect upon H:C ratio and are analogous to distillation. Hydrogenation and dehydrogenation change the ratio but not the size and are analogous to extraction. Isomerization changes neither. A 10-carbon fraction might be converted in any of four directions, although it could not be hydrogenated far without falling in carbon number. Conversions Affecting Carbon Number
All changing of carbon number was formerly done with heat alone. As the demand for gasoline had increased, larger and larger thermal-cracking units had been built to replace hundreds of small ones. Many large units are still in operation but almost no new ones have been built in the past decade. Better yields of naphtha result from catalytic processes, but even these break more carbon-carbon bonds than necessary. This difficulty is overcome by other processes in which the major reaction is creating carbon-carbon bonds. Together, conversions in the two directions have increased several fold the yield of naphtha produced from petroleum. Ca:ata&tic Cracking. Conversion of gas oil to naphtha over silica-alumina catalysts is now widely practiced. Completely continuous moving-bed and fluidized catalytic-cracking processes have gained favor until the number of units now exceeds 100 and about 30 per cent of all petroleum passes through them. Because efficient fluid units for small refineries are available, the number will perhaps soon approach 200. Eventually almost 50 per cent of petroleum will be processed in them. Catalysts of satisfactory activity can be made in many ways. Some are made synthetically from aluminum salts and silicates; others are simply acidtreated clays or even blast-furnace slag. A brisk market in used catalysts exists today; some refineries demand fresh and active catalyst and others prefer cheaper discard catalyst that is less active but more stable. A synthetic silica-magnesia catalyst has been tested commercially; the higher yield of naphtha obtained was offset by the lower octane number (4). The high octane number of the naphtha produced was a major factor in the acceptance of catalytic cracking. But another advantage must also be pointed out. The heat necessary for thermal cracking came from burning the gases produced-methane especially. The heat necessary for catalytic cracking comes from burning the coke that is formed on the catalyst. Re-
JOURNAL O f CHEMICAL EDUCATION
placement of the thermal by the catalytic process has shifted cracking from a hydrogen consumer to a carbon consumer. Although a thoroughly developed process, catalytic cracking still has problems. The capacity of refinery units is limited by the rate a t which the coke can be burned (If). Because the amount of coke formed increases with the H:C ratio of the feed, extracts are seldom catalytically cracked. The vanadium and other metals that are present in petroleum poison silicaalumina and prohibit the catalytic cracking of residues. Coking. Extracts and residues are usually converted to naphtha by the destructive-distillation process called coking. To refiners the coking process is both a benefit and a headache. Even streams with H:C ratios below about 1.5 can be cracked to naphtha, but semisolid hydrocarbons remain behind. They accumulate easily enough as roke in large drums, but getting it out is laborious. New coking processes that parallel moving-bed and fluid catalytic cracking simplify coke handling. I n fluid coking, the oil streams decompose in a fluidized bed of fine coke particles that grow until they reach about 0.1 mm. and are continuously withdrawn ($1). I n contact coking, a moving bed of coke particles that grow to 10 mm. in diameter is used (15). The rounded particles produced by both processes have H: C ratios as low as 0.3. Present conversions that decrease carbon number also affect H:C ratio. The reactions typical of catalytic cracking and coking fall diagonally in Figure 4. Some molecules crack to naphthas, but in doing this they rob hydrogen from others; these then undergo intermolecular dehydrogenation and increase in size as they become richer in carbon. Cycle oil or uncracked gas oil from catalytic cracking is too poor in hydrogen to be recycled, but too rich to be coked. Fortunately i t makes a fair fuel. Increasing Size. Two conversion processes, polymerization and alkylation, increase carbon number with little change in H:C ratio. Both start with olefins and are catalyzed by acids. Polymerization, the earliest of the catalytic conversions, uses phosphoric acid in some form as catalyst. The polymer produced from gaseous olefins is nearly all gasoline. Even before World War I1 most refineries polymerized mixed propylene and butylene made in thermal cracking. During the war many refineries polymerized butylene only and several hydrogenated the butylene dimer to hydrocodimer for aviation gasoline. Since the war, polymerization of mixed olefins is again customary; catalytic cracking is now the major source, and the mixtures are richer in propylene. Nearly 200 polymerization units are in operation; technical advances in recent years have been few. Alkylation of isobutane with olefins of three to five carbons uses sulfuric acid or hydrogen fluoride as the catalyst. The alkylate produced is nearly all gasoline of high octane number. About 30 alkylation units were built during the war to make isooctane for aviation
JANUARY, 1955
gasoline from the large amounts of isobutane formed in catalytic cracking. Afterward some units were shut down for several years. The increasing octane number of motor gasoline is bringing these hack on stream and several new ones are being built. Among the few recent advances are improvements in mixing acid and hydrocarbons-not easy because the difference in specific gravity is about threefold-and the successful use of 85 per cent sulfuric acid instead of the conventional 95 per cent (10). Ethylene is not usually converted to gasoline. Although two alkylation processes for doing so have been developed, little ethylene is available in concentrations above 10 per cent and enriching it is expensive. With isobutane, thermal alkylation of ethylene gives neohexane, and catalytic alkylation gives diisopropyl (2). The latter has an octane number well above 100 and recent advertising claims that it is now used in gasoline.
PROCESSES THAT DECREASE CARBON NUMBER I 2
I
I
/
VI
Z
= 9
/
cc4
'
-
5 -
/
-
Lr
lo
=#
20-
0
../ I
-
/
/ /
I
CONING
/
I 3
I
z
50-
0
I
CATALYTIC CRACKING
-
I
-
I
'
/I
/ //
I
I 1
I
2
3
4
HYDR0GEN:CARBON RATIO Fi-
4
sought various balances among these many reactions. Molybdena supported upon alumina was the first Octane numbers of gasolines have steadily increased reforming catalyst used. Eight units produced most until premium gasolines now rate above 92. Heavy of the toluene needed in World War 11. Dehydronaphthas distilled from petroleum often rate no more genation of cyclohexanes predominated, and only at than 40 and contain n-alkanes that rate far below zero. high temperatures and low pressures were high conThermal reforming of heavy naphtha once sufficed to centrations of arenes obtained. Cracking consumed raise the octane number; by merely cracking out some much hydrogen, and so much coke formed that the of the n-alkanes, ratings as high as 70 could be reached. catalyst had to be regenerated frequently. Less than 1 per cent platinum supported upon aluHalf measures no longer suffice; hydiocarbons well shove 100 octane number are needed in large quan- mina is a better catalyst. I t converts cyclopentanes tities to satisfy present high-compression engineslet as well as cyclohexanes to arenes. Use of high hydroalone future ones with still higher compression ratios. gen pressure almost prevents coke from formingat all. Becauje most arenes in the gasoline boiling range have If the temperature is kept low, little cracking occurs octane numbers above 100, they are the objective of and a good yield of hydrogen is obtained. With luck, today's fastest-growing conversion process-catalytic a catalyst need not be regenerated for years. Under suitable conditions platinum catalysts can reforming. I n much the same way that catalytic cracking improved upon thermal cracking, catalytic cyclize alkanes as well as dehydrogenate cycloalkanes. reforming is swiftly replacing thermal reforming. Low pressure, high temperature, and active catalyst Catalytic Reforming. Arenes are formed in catalytic must be used. Because these conditions lead to coke reforming principally by three reactions. Easiest t o formation, the catalyst must be periodically regencarry out is the dehydrogenation of cyclohexanes; erated. Only by use of techniques that go beyond harder is the isomerization of cyclopentanes to cyclo- burning off the coke can the catalyst he kept sufficiently hexanes and dehydrogenation of these; most difficult active. But gasolines of higher octane number can he is the cyclization of alkanes. Catalysts differ widely obtained thus in greater yields than in any other way in ability to accomplish them. (19). These reactions that liberate hydrogen are not the A serious engineering problem in catalytic reforming only ones that occur. Cracking, favored by higher is how to supply the endothermic heat of dehydrotemperatures, and saturation of olefins are side reactions genation. Fixed-bed processes usually use t v o or that consume hydrogen. When dehydrogenation pro- more reactors with intervening furnaces to reheat the ceeds too far, coke deposits upon the catalyst. Higher reactants. Use of a fluidized catalyst offers a way of hydrogen pressures decrease coke formation but only a t obtaining isothermal reaction and a fluid-molyhdena the expense of dehydrogenation. The several cata- unit recently began operation ( I 7); a fluid-platinum lytic-reforming processes that have been devised have process seems inevitable, but as yet none has been announced. Ten catalytic-reforming procexes have been deCatalytic-reforming Processes scribed. About 100 units are either in use or under Platinum catalyst construction in the United States; when all are onReferProcess OF. P . s. i. Regeneration ence stream, they will reform more than half the available heavy naphtha. Characteristics of three platinumPlatforming 875 600 None (W) Catforming 500 Occasional 900 (8) catalyst processes are given in the table, where the Ultraforming 950 300 Periodic (7) arrangement is by increasing temperature, or decreasing Conversions Affecting H:CRatio
34
JOURNAL OF CHEMICAL EDUCATION
pressure. Although the range of conditions covered seems narrow, operations differ widely. Platforming represents high-pressure operation without a regenerator (8.8). Catforming provides equipment for occasional regeneration (8). Ultraforming follows the low-pressure regenerative route and substitutes an extra reactor for those undergoing regeneration (7). Catalytic reforming has disadvantages. Instead PROCESSES THAT CHANGE HYDR0GEN:CARBON RATIO I
I
I
I
- .--I
HY0ROGEN:GARBON RATIO
of making more gasoline, as catalytic cracking does, i t destroys some hydrocarbons that already boil in the gasoline range. Heat content is greatly reduced by removal of hydrogen. The gains in engine power and performance provided by the higher octane number barely offset these sacrifices. Hydrogemtion. But the hydrogen made available by catalytic reforming is a decided asset. Some is already being couverted to ammonia, but eventually most will be used in petroleum relining. Figure 5 shows why. Conversion of naphtha to arenes produces hydrogen that can convert a heavier extract to a stream as rich in hydrogen as petroleum. Because of the different carbon numbers, one mole of naphtha gives enough hydrogen to improve three to four moles of the heavier extract. On the other hand, entirely too little hydrogen is produced to convert much carbon to naphtha. Hydrogen from catalytic reforming is most likely to be first used in upgradiog petroleum streams that already contain almost as much hydrogen as needed. Hydrogenations that reduce carbon npmber require so much more hydrogen that they will not appear in petroleum refineries as soon.
gas. Because octane number of alkanes depends upon branching, treatment of pentane and hexane with active catalysts, such as aluminum chloride, increases the octane number. Should higher octane numbers require them, ways for isomerizing alkanes above seven carbons will probably be devised. Alkenes produced from gas oil by thermal cracking were mostly straight chains with a double bond near the end. Isomerization of the double bond and rhain increased octane number, but not much. Alkenes formed in catalytic cracking are near thermodynamic equilibrium; isomerizing them holds no promise. The high octane numbers of all arenes leave little incentive to isomerize one to another for use in gasoline. Demand for individual arenes as chemicals does provide an incentive. For example, the meta isomer predominates in the xylenes made from petroleum, whereas the ortho and para isomers are most desired as chemical intermediates. Introduction of ratalytic conversions into petroleum refining emphasizes separations and simplifiesfinishing. Thermal conversions were not critical of the compositions of streams and the impurities in them. Catalytir conversions are affected by both; hydrogen-poor hydrocarbons form coke easily, and polar derivatives poison catalysts. At one time, such substances were removed, if necessary, as a final step and were discarded. The trend today is toward removing them before conversion and selling them if possible. Consequently, fewer impurities rearh the finishing step. FINISHING
Petroleum finishing has progressed far since "arid and caustic" wiw the only method used. Processes for bringing products up to specification quality have become more numerous. Color and odor; freezing point, vapor pressure, and boiling range; chemical composition and combustion behavior-these are but a few of the properties that must be checked and controlled constantly. The tasks of measurement and recording are tedious and automatic devices are being used wherever possible. Two main problems must be overcome before produrts leave the refinery: (1) small amounts of impurities remaining must be removed, and (2) undesirable reactions that may occur in storage or service must be prevented. Treating methods remove the impurities; additives prevent the undesired reactions. Trsating
Compounds of sulfur, nitrogen, and oxygen are the major impurities in petroleum; the amounts differ widely with the source. On the average, there is The last class of conversions are those that change about one such atom for every 100 carbon atoms. structure only. These processes are the isomerisations Many 25-carbon molecules, half the 50-carbon molecules, and almost all the larger molecules are not of nlkanes, alkenes, and arenes. The alkanes in petroleum are less branched than hydrocarbons at all. Metals also are found, even in thermodynamic equilibrium requires. Isobutane was distillates. Sulfur is the most abundant impurity. During made from n-butane for use in alkylation during World War I1 but most of it now comes directly from natural separation and conversion processes, hydrogen sulfide Convarsions Affecting N a i t h e ~Carbon Numbel* nor H:C Ratio
JANUARY, 1955
35
from decomposition of sulfur compounds collects in the speed with which most hydrocarbons oxidize in the hydrocarbon gases. Several refineries are recov- air become appreciated. The knowledge has yet t o ering sulfur from this source by controlled oxidation be applied, but it has emphasized the value of predent (1). New sweetening processes for eliminating mer- inhibitors. captans or thiols are replacing the lead oxide reagent Control of the combustion of fuels by traces of semiused in the old doctor process. Air is the oxidizing combustible substances is a busy field of research. agent, and copper chloride is the usual catalyst (16). Tetraethyllead has been used for years and tricresyl Less reactive sulfur compounds, in which the sulfur phosphate has recently been promoted. All such is buried in rings, require more drastic methods. The additives are mixed blessings. Research aimed a t best known of these is hydrofining with rugged metal- determining the circumstances in which advantages sulGde catalysts (5). Two molecules of hydrogen are outweigh disadvantages is fantastically complicated. consumed, one for the sulfur and the other to ~aturate Refiners are rightly reluctant to adopt new ones until the vacated linkages. The hydrogen may be supplied thorough studies in each of their own fuels are made. either from outside sources or by simultaneous partial CONCLUSION dehydrogenation of the stream. Nitrogen and metals are often associated as porI n retrospect, petroleum refining has changed markphyrin complexes. In most crude petroleum the edly since World War 11. Replacement of thermal amounts of both are small but important. Ammonia by catalytic conversions, barely started then, is perhaps and amines poison the acid catalysts used in poly- two-thirds complete. Diesel fuels instead of coal run merization and the metals poison cracking catalysts. the railroads. Manufacture of chemicals has become They may remain undetected, and the consequences integrated with refining. New knowledge of separaare easily attributed to blameless factors. Methods tions and conversions is ready for application where of removing them from crude oil, although needed, needed. Looking ahead, one asks how the next decade have not yet been widely adopted. can possibly advance as far--until one remembers Oxygen compounds have been given little attention. that that was the very question asked a decade ago. However, phenols are often recovered from cracked LITERATURE CITED naphthas by scrubbing with caustic. In service, some nonhydrocarbons are desirable in (1) ANON.,Chem. Eng. News, 30,3094 (1952). Ind. Eng. Chem., 39,1273 petroleum products and not all hydrocarbons are (2) AXE, W. N., AND W. A. SCHULZE, (1947); THOMPSON, R. B., AND J. A. CHENICEK, ibid., 40, desirable. Nitrogen and oxygen compounds inhibit 1265 (1948). oxidation of stored fuels, but the effect is small and (3) COLE,R. M., AND D . D . DAVIDSON, I d . Eng. Chem., 41, better protection is afforded by adding synthetic in2711 -. - - (lQ49) .-.",. hibitors. Highly unsaturated hydrocarbons that may (4) CONN,A. L., W. F. MEEHAN, A K D R. V. SHANKLASD, Chem. Eng. Progr., 46, 176 (1950). oxidize to acids or polymerize to gums are now fre(5) . . EVANS,T. W.. "Recent advances in ~etrochemicals."J. quently removed with spent conversion catalysts: c&. EDUC:,in press. sulfuric acid from alkylation instead of fresh acid, and (6) FARRINOTON, B B., "Recent advances in the lubrication silica-alumina from catalytic cracking instead of clay. field,'' presented at the 125th Meeting of the A. C. S., Kansas City, Ma., Msreh, 1954. Particularly undesirable in petroleum products are J. H., A. L. CONN,AND J. B. MALLOY, paper polycyclic arenes that cause tumors in laboratory (7) FORRESTER, presented before the Western Petrpleum Refiners' Assn., animals. Although rare in crude petroleum, small San Antonio, Msreh, 1054. amounts of carcinogens occur in the high-boiling hy(8) FOWLE,M. J., R. D. BENT,AXD G. P. MASOLOGITES, Proc. drogen-poor products from some catalytic conversions. Am. Petrokmlnst., 32 (3), 197 (1952). JR., Chem. They contain 20 or more carbons, boil between the (9) HARPER,J. I., J. L. OLSEN,AND F. R. SHERMAN, Eno. (19521. " Proo.. " ,48.276 . ~, fuels and lubricants, and are removed in the refining (10) HUGHES,E. C., D. G. STEVENS,AND FRANKLIN YEATCH, of both. Streams from catalytic cracking that might Ind. Eng. Chmn.,43, 1447 (1951). contain them are recycled through the units where they (11) JOHNSON, M. F. L., AND H. C. MAYLAND, paper presented before the Divifiion of Petroleum Chemistry at the are adsorbed upon the catalyst and are burned during 124th Meeting of the A. C. S., Chicago, September, 1953. regeneration. Other streams suspected of containing (12) LIEN,A. P., paper presented before the Division of Petrothem are coked or burned in the refinery as fuel. leum Chemistrv at the 125th hleetine of the A. C. S.. \
Additives
Inhibitors, soaps, polymers, and other additives have improved stability, detergency, viscosity, and other properties of lubricants for years. The practice now extends to other products. Use of rust preventives in diesel fuels is an example. Some additives control deterioration before use and others affect behavior during use. Oxidation is the most important reaction against which products need protection. Only rerently has
Knnsas City, MO.,March, 1954. LIEN, A. P., D . A. MCCAULAY, AND B. L. EVERING, Ind. Eng. Chem., 41, 2698 (1949); L~EN,A. P., ASD B. L. EVERING, ibid., 44, 874 (1952). MAYFIELD, F. D., W. I,. CHURCH, JR., A. C. GREEN,D C. ibid., 44, 2238 (1952); LEE, JR., AND R. W. RASMUSEON, SCHOFIELD, R. C., Chem. Eny. Pmgr., 46, 405 (1950). MEKLER, V., A. H. SCHZPITE. A N D T. T. WHIPPLE, PIOC.Am Petroleum Inst.. 33 (31. 47 (19531. ~, (16) ROSENWA~.D, R. H., ~ e i ; o / e u mPlocessing, 6,969 (1951). ( l i ) SEEBOLD, J. E., J. W. BERTETTI, J. F. SNUGGS,A X D J. A. BOCK,Oil Gas J., 51 (2), 111 (1952). (18) SMITH,H. M. "Recent advances in the composition of
JOURNAL OF CHEMICAL EDUCATION
36
(19) (20)
~.
121) (22)
petroleum," presented a t the 125th Meeting of the A. C. S., Kansas City, Ma., March, 1954. STEEL,R. A,, J. A. BOCK,W. R. HERTWIG,AND DL.W. RUSSUM,paper presented before the Am. Petroleum Inst., Houston, May, 1954. THORNTON, D. P., Ja., Petroleum Processing,7,498 (1952); READ,D., Petrokum Refiner, 31 (5), 97 (1952). V o o m ~ sA,. . JR.. AND H. 2. MARTIN.Proc. Am. Petroleum Inst., 3$(3j, 39 i1953). WEINERT,P. C., M. J. STERBA,V. HAENSEL,AND H. W. GROTE,Proe. Am. P e t r o l m Inst., 32 (3), 187 (1952). ~
WILSON,R. E.,Advances in Chem. Ser., 5 , "Progress in petroleum technology". 1 (1951), and accompanying papers. ~IMMERSCHIED, W. J., R. A. DINERSTEIN, A. W. WEITKAMP, AND R. F. MARSCENER, J. Am. C h . Soe., 71, 2947 (1949); Ind. Enq. C h . , 42, 1300 (1950); BAILEY, W. A,, JR., R. A. BANNEROT, L. C. FETTERLY, and A. G. SMITH,ibid., 43, 2125 (1951); KOBE,K. A,, AND W. G. DOMASK, Petrokum Refiner, 31 (3), 106; 31 (5), 151; 31 (7), 125 (1952); HEW, H. J., G. C. RAY,A N D E. 0. Box, Ind. Eng. Chnn., 45,112 (1953).
