Plant-394.* Progress in Refining of Crude Petroleum. A . L . F o ster. Petrol. Engr, Midyear 1940, 11 (10), 28-34.— Trends of refining progress in 1939 h ave been in the direction of increased specialization in personnel, process, an d product. T h e first is shown
A B S T R A C T S . 1 5 5 a by the m uch greater use of technical gradu ates not only in the research and develop
ment departm ents, b u t also in the operating an d m aintenance divisions. T his trend can also be seen in the w ider use of pilot plan ts and sem i-plant scale units designed to bridge the gap betw een test-tube scale laboratory operations an d the full-scale operation of the com m ercial plan t th a t m u st be econom ically profitable.
In the field of process developm ent the control of plan t processing in the light of product requirem ents w as particularly outstand ing in 1939. More than ever, the processes u sed b y the refiner determ ine the properties the product will exh ibit, and bearing in m ind the qualities dem anded b y com petition an d b y the consum ers’ needs, the refiner works to produce the product required. Of the processes which have recently come to the fore, the m ost im portant are catalytic polym erization and alkyla- tion, especially the latter. In th is process an olefine is com bined w ith a norm al paraffin to form an isoparaffin in the motor- an d aviation-fuel boiling ran ges. Sulphuric acid is the m ost general cataly st, but others m ay soon be brought into commercial use. In com bination w ith these two processes, catalytic dehydrogenation of paraffins to the corresponding d efin es is carried out on a large scale, using oxides of A l, N i, Cr, Fe, and V a s cataly sts.
Therm al dehydrogenation and alkylation are also processes in use com m ercially, a m ost im portant exam ple being the therm al dehydrogenation of ethane to ethylene and its addition to isobutane to yield neo-hexane— a volatile high-octane-number constituent of 100 octane fuels. L e ss well developed are processes of isom erization been confined alm ost entirely to solvent extraction for rem oval of naphthenic, arom atic, and other undesirable fraction s, an d for rem oval of w ax. The technique of filtration
tergents include, besides so ap s an d esters, sub stitu ted organic m aterials, both aliphatic and arom atic.
In the developm ent of new products, m any typ es of m aterial are now synthesized commercially from petroleum . Solven ts, alcohols, resins, plastics, synthetic rubbers, including b u ty l rubber an d buna, are all derived from m aterials of petroleum origin,
junction w ith conventional h eat exch angers, reboiler or kettle, reflux coolers and con
densers, tem perature controls, back-pressure regulators, liquid-level controls, feed and
content to 4-5 lb./lOOO brl. in winter an d as low as 2-5 lb./lOOO brl. in summer. In by 1938. Certain faults were found, and the correction of these faults an d the develop
ment of a newer and im proved typ e drum are the su b ject of the paper. This type is the I.C.C. 5E . drum with 20-gauge sidewall.
A test program m e in studying the new typ e drum included the following : (1) physical and chemical characteristics of the steels used, an d fabricating techniques;
(2) effect of yield-point of steel on the stab ility of sw edged-out rolling hoops ; (3) effect of yield-point on resistance to denting and w eaving ; (4) service tests to compare the 20-gauge I.C.C. 5E . drum of stiff steel with the all 18-gauge I.C .C . 5 E . drum fabricated from ordinary so ft steels. The test program m e w as in augurated during October 1938, and extended over a period of a year. T h e tests are described, an d the results are illustrated by photographs. R esu lts are favourable.
In developing the drum a s a single-trip container it w as intended to be used primarily for hazardous liquids of low specific gravity, such a s alcohol an d various solvents.
This drum should not be overloaded, an d the com m ittee h as recom m ended th at the m axim um nett weight of contents shipped therein should not exceed 450 lb. Better- quality sheet steel is now available, an d im provem ents in design an d fabrication have been m ade. I t is expected th at the I.C .C . 5 E . drum w ith 20-gauge sidew all will be commercial heat-transfer fluids now available for in stallation s in which the tempera- true of steam is insufficient and in which flue g a s is inapplicable, for an y reason. the stability, corrosion effects, safety precautions, an d explosibility are all discussed.
A . H . N.
A B S T R A C T S . 157 a
399.* New Trends in Boiler Feed-Water Treatment. F . G. S trau b. Chem. Met.
Eng., Ju ly 1940, 47 (7), 477-479.— The m ost com m on classification of boiler feed-water problems is (1) scale, (2) corrosion, (3) em brittlem ent, an d (4) carry-over. The first two difficulties m ay be experienced a t all points in the w ater-stream cycle of the power plant, whereas the la st two occur only in the steam boiler. There are m any m ethods of boiler-water treatm en t which prove suitable for one or all of these problem s. H ow ever, the m ethods of a tta c k m ay bo roughly classified a s treatm ents used internal or the rem oval of the oxygen from the w ater prior to entering the boiler feed-lines. This has resulted in alm o st universal chem ical treatm ent being resorted to for the elim ination of the last trace of oxygen left after deaeration. Chemicals such as iron, ferrous hydroxide, sodium sulphite, an d various organic m aterials are being extensively used.
E m brittlem ent in steam boilers results in the failure of the steel in the riveted areas and the areas in the vicinity of the rolled tube-ends. T his failure h as been attribu ted to the action of the sodium hydroxide in the boiler-water concentrating in the capillary spaces present in th ese areas an d attack in g the highly stressed boiler m etal, with the resultant cracking of th e steel. M ethods of chem ical treatm ent have been w orked out whereby the em brittling action of the w ater m ay be stopped. T his h as involved the maintenance of definite am ounts of sulph ates an d chlorides or organic m aterial in the lower-pressure boilers an d the reducing of the silica content in the higher-pressure boilers.
W ashing steam w ith feed-w ater, to reduce the total solids carried over b y the steam , and thus to reduce difficulties in the form of turbine-blade deposits, form s the con crudes containing appreciable quan tities of toluol is quite lim ited. No com prehensive study of A m erican crudes w ith respect to toluol content is available.
It is noted th a t even if a “ toluene fraction ” of a nap h th a were entirely toluene, and if a n ap h th a containing
6
% of this fraction constituted 30% of th e crude, the toluene content of the crude w ould be only1
-8
% .To obtain more toluol for T .N .T . purposes other m eans are necessary. One prom ising method is th at for which the groundw ork w as laid during world W ar I — low-pressure, high-temperature cracking of petroleum oils. There is som e evidence th a t the characteristics of the oils do not play a s v ita l a p art in the yields of toluene as do the conditions under which cracking is carried out. D etails of cracking processes are given.
A third m eans of producing toluol ex ists in the therm al pyrolysis of hydrocarbon gases from petroleum , such as n atu ral g a s an d the cracked gases m ade in refineries as by-products. A s in the cracking of liquid feed-stocks, the reactions of the process are complex, and result in considerable am ounts of d efin es and arom atics.
The production of toluol b y the cataly tic arom atization of n-heptane is another
401.* Economy in Tube Grouping in Round-Shell Exchangers. Z. G. D eutsch. Cliem.
Met. Eng., A ugust 1940, 47 (
8
), 538-540.— T h e general requirem ent of the tube-sheet158 a A B S T R A C T S .
itself, outside the elementary one of strength to resist bursting pressure or vacuum collapse, is to support the tubes with a tigh t, m aintenance-free joint. When the fluids separated by the tube surfaces of a h eat exch anger have nearly the sam e density and specific heat, the cross-sectional areas should be a s nearly alike as possible. This is not invariably true, but frequently so in the au th or’s practical experience. For such problems the best approach to “ theoretical ” econom y of m aterials is obtained by using the sm allest tube diam eter, the longest tubes, the closest possible tube spacing, the thinnest possible tube walls th at can be justified.
The paper discusses further the arrangem ents of tubes in the shell, and two typical arrangements are shown to be preferable to the other tw o studied. Tables and charts are given so that designers can utilize them in arriving a t an economical number of tubes and a preferable arrangem ent of such a num ber of tubes to an y other.
The d ata in this paper have been com puted only up to ab ou t 120 tubes. With larger numbers of tubes there is relatively less difference in area ratio. Also, in working with larger tube bundles the designer is generally faced with circumstances which make the use of a perfectly sym m etrical bundle less an d less likely. This is because it is necessary to accom m odate certain nozzles, connections, circulating pipes, etc., which interfere with the uniform placem ent of tubes across the entire cross-
sectional area of the shell. A . H . N.
402.* Gulf Introduces New Petroleum Refining Process. Anon. Chem. Met. Eng., Septem ber 1940, 47 (9), 626.— The polyform process differs from therm al cracking in that the oil is processed in adm ixture with norm ally gaseous h ydrocarbons, particularly propane and butane, a t higher tem peratures an d pressures. The result is a higher degree of conversion/pass, with a consequent increase in yield an d octane number.
The theory of the process is that, in addition to the norm al cracking of long hydro
carbon molecules which is obtained a t these high tem peratures an d pressures (about 1000° F . and 1000 lb./sq. in.), a certain am ount of polym erization of the C3 and C
4
hydrocarbons will occur. Also the introduction of the gases cuts down coke formation, allowing the unit to operate a t higher tem peratures, w ith the consequent increase in conversion/pass.
The principle of the process is th at the charge to the furnace m u st be one continuous phase. Normally, the liquid phase tends to be suspended in the vapou r ph ase (largely the gaseous additives) in the form of m inute droplets. T h ese are thrown out against the tube wall, forming a thin oil film. H eat tran sm itted through the tube wall must pass through this oil film, which therefore determ ines the coking characteristics of the tube. In order to produce a continuous vapour ph ase, the proportion of light hydro
carbons m ust be increased to a point where the critical tem perature of the m ixture is reduced to the tem perature of operation. T his does aw ay w ith the oil film, substitut
ing a vapour film, which is less susceptible to coking.
D etails of a typical plant are given. A . H . N.
403.* Notes on the Design and Operation of a High-Temperature Dowtherm System.
R . E . Hulm e. Chem. Met. E ng., October 1940, 47 (10), 685—687.— D ow therm is the eutectic m ixture of diphenyl and diphenyl oxide. M any high-tem perature heating processes are now being carried out through the use of indirect heat-transfer media such as Dowtherm. Com pared to direct heating, an y vapour m edium m akes possible much closer control, usually w ith m arked im provem ent in yield an d qu ality of the product. In com parison w ith steam , however, D ow therm vapour perm its tem pera
tures up to about 700° F . a t relatively low jack et pressures, an d still w ithout appreciable deterioration of the m edium . However, m any new problem s in design, m aterials, and technique are thus introduced. Several of these problem s of m anipulating, main
taining, and controlling Dowtherm sy stem s are discussed. A . H . N.
404.* Safety and Fire Prevention. Anon. Chem. Met. E n g ., O ctober 1940, 47 (10), 700-706. The paper deals with Am erican safety organizations and recommendations.
After studying the frequency and severity of various typ es of accidents an d analysing their causes, the following conclusions sum m arize the findings of the w riters.
Chemical industry in 1939 set som e enviable records in accident prevention, ranking seventh in frequency and seventeenth in severity am ong the th irty m ajor injuries
A B S T R A C T S . 159 a
Accidents annually cost chemical industry approxim ately S 10,000,000, or S40 per worker/year. There are handsom e dividends in safety work for those who ap p ly it where vertical pum ps are finding considerable application for process liquid handling is the petroleum in dustry. F o r quick unloading of crude oil or fuel oil from tankers to barges or shore, deep-well turbine pum ps are being installed directly on the boats, with the m otors above decks an d the pum ps subm erged in the oil com partm ents of the tanker’s hold. T h is h as proved to be an econom ical and safe unloading m ethod.
In refinery operation, and also in handling such refinery products as gasoline and butane, the vertical pum p is finding wide application. F o r use where the service is hazardous, som e pum p designers have brought out special pum ps in which the motor is subm erged in an isolating liquid, so th a t fire or explosion hazard is m inimized.
In pum ps of this typ e the m otor, below the pum p, and the pum p itself are inserted in a heavy cylindrical b arrel an d suspended from the flanged barrel cover. The m otor runs in oil, and a m ercury seal prevents the pum ped liquid from entering the motor.
The lower p a rt of the barrel, surrounding the subm ersible m otor, is filled with an isolat
ing liquid th a t is im m iscible w ith the liquid being pum ped. T his prevents the p o ssi a great help in m aking in stallation s in crow ded locations or directly on the equipm ent served by the pum p.
Where positive delivery in exact quantities is in dem and for process work, the rotary pump continues to give excellent service. A n exam ple is given of seven ro tary pum ps
in a lubricating-oil blending p lan t. A . H . N .
406.* South African Materials as Substitutes for Imported Earths in Connection with Oil Refining. G. A . Sm ith. J . Chem. Met. and M in. Soc. S . A frica, 1940, 41, 197—
208.—An investigation into the possib ility of finding South-African-produced sub stitu tes for lubricating-oil refining earth is detailed. N orm ally such m aterial would be fuller’s earth, bentonites, b au xite, silica gel, or carbon. B a u x ite an d bentonites are not available in South A frica, an d silica gel is not considered to be very efficient for lubricating-oil refinem ent. The investigation was therefore m ainly concerned with the little fuller’s earth which w as av ailable, w ith carbon and with two "unusual possibilities
—namely, verm iculite, a form of m ica, an d m agnesite or naturally occurring m agnesium carbonate.
160 a A B S T R A C T S .
The improvement in colour when a used lubricating oil is agitated for a standard time at 150° C. was utilized to assess the efficiency of each of the m aterials used.
An active form of m agnesium oxide was prepared by calcining m agnesite at 700° C.
Although slightly inferior to recognized treatin g earth s in decolorizing ability, the active magnesia produced a t least as stab le a regenerated oil, judged by British Air Ministry oxidation tests, etc., as a highly active bentonite. The filtration rate of the mavnesia-treated oil is slow, but can be im proved by the addition of diatomaceous earth. The latter increases the porosity of the m agn esia slim e p ad formed during
filtration. . . , ,
The temperature of calcining the m agnesite is critical, an d heating above 700° C.
reduces the activity of the product. P article size m u st be less th an 200 B .S .S . mesh.
The production cost of the m agnesia in South A frica is calculated to be \d . per lb.
Im ported earth costs 5\d. per lb.
Attention is directed to a m ethod of preparing active m agn esia by the lime precipita
tion and subsequent calcination of m agnesium hydroxide from sea-w ater.
Fine-mesh active carbon produced from South A frican coal w as found to have extremely good oil-refining properties.
E xfoliated vermiculite, which, because of its very large surface area, w as expected to be very efficient, w as, in fact, very disappointing. I t s failure is attribu ted to lack of the “ capillary pores ” which in an active m aterial absorb the colouring m atter in oil.The attem pt to find a suitable South A frican clay w as not successful. A partly active clay w as produced in the R iversdale district, an d the activ ity of this was im
proved by acid-washing to rem ove carbonates, b u t the results were not impressive, and it was concluded th at South A frica does not p o ssess an y n atu ral treating clays.
D uring the work it w as dem onstrated th a t there is no correlation between the malachite-green absorptive power of a clay and its decolorizing ab ility . T . C. G. T.
407.* Slurry-Type Copper Chloride Treater. F . A . D eering, Oil Oas 5.9.40, 39 (17),
43
.— Hypochlorite treatm ent of stabilized light straigh t-run m ixed with cracked gasoline h as been replaced a t an A rk an sas City refinery b y treatm ent with a slurry of 200-mesh fuller’s earth and copper chloride. The gasoline is caustic washed, dehydrated in a salt tower, steam h eated an d p a ssed to the b ase of the slurry tower.Before the tower, an eductor leads oxygen (averaging J cu. ft. per brl., b u t depending on the m ercaptan content) into the stream . The stream leaving the slurry tower is water-washed, and scrubbed with w ater and p assed into a further salt tower. The final product is doctor sweet, clear, an d bright. A blend of 20% copper-treated stock and 80% cracked gasoline requires
12
% less tetra-eth yl lead th an when using hypochlorite, whilst the induction period is approxim ately 30 m in. longer. C. L . G.408. Patents on Refining and Refinery Plant. W. W. Groves. E .P . 531,120, 30.12.40.
Appl. 12.7.39. Im provem ent in the process of dew axing hydrocarbon oils, such as mineral oils, tars, etc., in which the oil is diluted w ith a m ixture of liquid sulphur dioxide and an auxiliary solvent which increases the solvent pow er of the sulphur dioxide. According to the invention, the oil to be dew axed is p a ssed after dilution into chillers having scraping devices and constructed a s double pipe-chillers in counter- current to cold liquid sulphur dioxide.
C. H . Leach. E .P . 532,604, 28.1.41. A ppl. 11.9.39. D esign of a heat-exchange ap paratus intended particularly for use in refining petroleum oil. The apparatus comprises a fixed head, a plurality of floating h eads spaced from the fixed head, heat- exchange tubes connected betw een the fixed an d floating h eads to form a fluid passage, a shell enclosing the tubes and floating heads, and a baffle inside the shell for forming a vapour passage.
Standard Oil D evelopm ent Com pany. E .P . 532,792, 30.1.41. A ppl. 20.8.39.
Method of separation of a hydrocarbon fraction of the class of n ap h th a, kerosine, and light gas-oil into its relatively more paraffinic and relatively more arom atic constituents.
The hydrocarbon fraction is separated with tetraethylene glycol.
A B S T R A C T S . 161 A R . E . B u rk an d E . C. H ugh es. U .S .P . 2,22.5,546, 17.12.40. A ppl. 31.12.37.
Process for dew axing oils b y sub jectin g them to the action of butylam ine, chilling, and separating the w ax.
B . H opper. U .S .P . 2,227,089, 31.12.40. A ppl. 7.2.38. Stabilization of oil treated with a copper reagent in the presence of oxygen. The copper-sweetened oil is treated
B . H opper. U .S .P . 2,227,089, 31.12.40. A ppl. 7.2.38. Stabilization of oil treated with a copper reagent in the presence of oxygen. The copper-sweetened oil is treated