BRITISH CHEMICAL ABSTRACTS
B.—APPLIED CHEMISTRY
A P R IL 10 and 17, 1931.*
I.— GENERAL; PLANT; MACHINERY.
Portable pyrom etric cone-equivalent furnace.
V. C a r t w r i g h t and S. M. P h e l p s (J. Amer. Ceram.
Soc., 1931, 14, 1—7).—The development of a portable furnace which weighs about 110 lb., uses compressed gas (natural gas or propane) as fuel, and will a t the proper rate of heating attain a tem perature of cone 34, is fully described and illustrated. R. J. C a r t l i d g e .
[Tunnel] dryer problem s w ith calculations.
J. L. Ca r r u t h e r s(J. Amer. Ceram. Soc., 1931,14,8—20).
—Drying operations are discussed and a method of using humidity charts to enable such problems as the preven
tion of condensation and the proper control of tempera
ture, volume, and hum idity of air in waste-heat and radiated-heat dryers to be solved is described.
R. J. Ca r t l i d g e.
T em perature distribution in intern ally heated cylinders. A. B. Newman (Ind. Eng. Chem., 1931, 23, 29—32).—Theoretical. The theory is developed of the flow of heat through the thick walls of a hollow cylinder heated internally. Reference is made to the practical uses to which the curves and formulae deduced
may be put. H . I n g l e s o n .
Modern grinding. T. C. Fa r r a n t (Soc. Chem.
Ind., Chem. Eng. Group, 1931. Advance proof. 32 pp.).
—Grinding mills may be divided into three groups : (i) slow-speed mills in which attrition and impact are the chief factors, e.g., pan mills, burrstone, ball mills suitable for silica ; (ii) medium-spced mills depending chiefly on compression, e.g., roller mills, suitable for phosphates; and (iii) high-speed mills depending largely on impact and shearing, suitable for precipitated and light materials. Power consumption depends largely on toughness. The closed circuit with air separation has many advantages, and its scope has been extended to abrasive materials by placing the fan on the remote side of the cyclone and sealing the bottom of the latter. For wet grinding, pan mills, edge- runners, burrstones, ball mills, and to a less extent stamp mills are chiefly used. Recent developments include the use of the close circuit with classifiers, notably the Andrews classifier. In the closed circuit the fineness of the product is controlled by the circulating load, quan
tity of water used, speed of mill, and fineness of grinding media. For pulverised fuel groups (i) and (ii) are indicated for the central system ; for the unit system all groups are used, but preferably mills in group (iii), because of the small floor space required and simplicity:
Operating data are given, and various types of mills
are illustrated. D. K. Mo o r e.
Conception and measurement of plasticity.
C.g.s. unit, and a new plastometer. E. Ka r r e r
(Z. tech. Physik, 1930, 11, 326—337; Chem. Zentr., 1930, ii, 3175).—Plasticity is defined as the ability to suffer and to retain changes of shape. A unit is defined and an apparatus described. A. A. E l d r i d g e .
Recording dust-concentration m eter and its application to th e b la st furnace. A. W . Sim o n,
L. C. Kr o n, C. H. Wa t s o n, and H. Ra y m o n d (Rev. Sci.
Instr., 1931, 2, 67—83).—An exponential expression connecting the light transm itted by a gas containing suspended m atter and the concentration of the latter is deduced, and the construction of a meter, involving the use of a thermopile as the light-sensitive element, is
described. C. W . Gi b b y.
Sulphuric acid.—See VII.
See also A., Mar., 318, C atalytic gas reactions.
330, Vacuum evaporation etc. Gas an alysis.
Pa t e n t s.
R otary furnaces for soda-recovery plants. J.
Ho l m e s and II. A. Kin g c o m e (B.P. 342,545, 12.2.30).—
Spent liquor from paper works is fed to the burner end of a rotary furnace and from the other end drops into a secondary furnace, where combustion takes place between the carbon and additional air ; finally the soda drops in a molten condition into water. The rotary furnace is provided with internal scrapers a t the cooler end and with air seals between the moving and fixed parts, the waste gases passing to a waste-heat boiler.
B . M . Ve n a b l e s.
Steam -heated drying cylinders. S . F . Ba r c l a y, H . Ho y l e, and Ma t h e r & Pl a t t, Lt d. (B.P. 342,513, 28.1.30).—W ater of condensation is lilted out of a drying cylinder to the discharge trunnion by a device comprising alternate spirals and cylinders of decreasing diameter. Each spiral is duplicated by one of opposite hand so th a t the drum may be rotated in either direction.
B . M . Ve n a b l e s.
D rying m achine [for tex tile m aterials etc.].
B. A. Pa r s e s (U.S.P. 1,773,852, 26.8.30. Appl., 18.5.29).—The materials are dried by air blown through them while they are sandwiched between two perforated belt or apron conveyors.: The conveyors form a circular loop within which the circulating fan runs a t a higher
speed. B. M. Ve n a b l e s.
T ran sm ittin g heat to and regulatin g th e te m perature of d ryers, heaters, and the lik e. C o k e &
G a s O v e n s , L t d . , and T. B. S m i t h (B.P. 342,291, 21.10.29).—A vessel is heated by hot fluid, e.g., oil, circulating through a jacket. The separate heater for the oil has an open or vented top permitting expansion of the oil, the rise of level operating a float which controls the supply of heating fu e l; thus the actual tem perature
* The rem ainder of th is se t of A bstracts will appear in n ex t week’s issue.
321 a
B r itis h C h e m ic a l A b s tr a c ts —B .
322 Cl. I .—General ; Plant ; Machinery.
of the oil may be regulated by adjusting the total amount in the system (cf. B.P. 256,385; B., 1926, 915).
Application to the drying of ammonium sulphate is
indicated. B. M. Ve n a b l e s.
D rying or roasting clay, carbon, etc. F. M.
H a r t f o r d , Assr. to H a r r o p C e r a m i c S e r v i c e Co. (U.S.P. 1,773,675, 19.8.30. Appl., 1.3.28).—A tunnel kiln is operated, with transverse circulation of the drying or roasting gases and a general slower movement either con- or counter-current to the goods. The circulation is from and to a pair of longitudinal flues in the roof, which are subdivided to suit the number of circulating fans provided. The circulating currents are directed through the goods a t different levels by curved recesses in the walls, which terminate a t different heights.
B. M. Ve n a b l e s.
T reating [drying of m o ist] m aterial [lactose etc.]. E. T. Me a k i n (U.S.P. 1,766,030, 24.6.30. Appl., 2.8.26).—Material such as casein or lactose is dried by dropping it into a rising current of air in which it remains dancing until sufficiently dried. A number of vertical drums are arranged side by side, and each is provided with, an upward current of air, the outlet for which is a t the end of the series remote from the fe ed ; the air from any earlier drum passes through controllable shutters in the upper wall (above the level of the original feed), across all the later drums, to a collecting hopper and cyclone where the material is collected.
B. M. Ve n a b l e s.
Grinding m ill. J. Kl a g s b r u n n, Assr. to P. Le g r a n d
(U.S.P. 1,773,906, 26.8.30. Appl., 21.11.27. Austr., 26.11.26).—A m ill h a v i n g a g r i n d i n g d is c w i t h t e e t h o u t s t a n d i n g f r o m i t s s u r f a c e a n d f ix e d r i n g s w i t h a w a v y s u r f a c e is d e s c r ib e d . B. M. Ve n a b l e s.
Centrifugal [grinding] m ills. E. Ra p p, and Sc h n e l l- p r e s s e n f a b r. A.-G. He i d e l b e r g (B.P. 342,507, 22.1.30).
—The apparatus is provided with a rotating disc and central inlet. The disc has upstanding beaters in the form of vanes which are interrupted not far from the circumference, and stationary grinding bars project into the spaces. B. M. Ve n a b l e s.
Revolving drum for m ix in g , shaking, and cracking. J. E. Po l l a k. From Ma c h i n e f a b r i e k
I.H.O.R. (B.P. 342,541, 10.2.30).—The lower p art (when stationary) of a revolving dram is formed as a vehicle capable of being run away on rails and duplicated to keep the drum in almost continuous operation.
B. M. Ve n a b l e s.
Apparatus for cooling liquids [e.g., m ilk ]. F. W.
Ca v e, and La w r e n c e& Co., Lt d. (B.P. 342,265,21.10.29).
—A tubular cooler which may have to be made of steel or other corrodible material in order to resist pressure is covered closely with corrugated sheets of a corrosion- resisting metal over which the streams of liquid to be cooled flow. To obtain good heat-transference the casing is joined to headers a t the ends surrounding the return bends of the inner tubes, and the space is either filled with brine or some good conducting liquid, or is subjected to a vacuum which draws the outer cover closely in contact with the tubes. B. M. Ve n a b l e s.
M easuring the concentration of solids in liqu ids.
H. J. K e r r , Assr. to B a b c o c k & W i l c o x Co. (U.S.P.
1,773,735, 26.8.30. Appl., 18.2.21. Renewed 5.10.28).—
A vessel is described in which the electrical conductivity of, e.g., boiler water can be measured a t a reasonably constant temperature. A portion of the liquid under pressure is adm itted to the top of the vessel through a small orifice, the vessel being covered but vented to atmosphere so th a t part of the liquid flashes into vapour and the remainder passes downward through the vessel to a siphon outlet a t the bottom. In this way the bulk of the liquid is held a t the atmospheric b.p., and is also constantly renewed to give a continuous sample of the contents of the boiler. B . M. Ve n a b l e s.
Centrifugal separators for liquids containing so lid s. G. t e r Me e r (B.P. 342,589, 24.3.30).—A centri
fuge of the strainer type is provided with permeable zones through the other walls of the basket, in addition to the usual ones through the circumferential wall. The auxiliary apertures are less likely to choke, because they are not subjected to the full centrifugal force, and are useful for discharging liquor from the later instalments of
feed. B. M . Ve n a b l e s.
Apparatus for separating pulverised solid s from a gaseou s current. Fo u r s e t Ap p a r e i l s St e i n (B.P.
342,594, 26.3.30. Fr., 30.4.29).—An apparatus of the change-of-direction type is described, the finer particles being allowed to pass on into the fan. B. M . Ve n a b l e s.
Filter casing and its operation. E . J . Sw e e t l a n d
(U.S.P. 1,774,044, 26.8.30. Appl., 28.10.25).—A vacuum filter of any type is placed, as a whole, inside a casing and operated under compressed air. B . M. Ve n a b l e s.
Apparatus for cry sta llisa tion from solution s b y evaporation under reduced p ressu re. E . L. R. A.
Sc h i e l e and F. H . Wi t t e n b u r g (R. 0. Me y e r) and
Ku p f e r h u t t e Er t e l, Be e b e r & Co. ( B .P . 342,449, 4.12.29. Ger., 4.12.28).—The apparatus comprises a single shell divided into a number of compartments each having its own evacuating means and s tirre r;
only the last of the series has an overflow for mother- liquor with the crystals in suspension.
B . M . Ve n a b l e s.
D esiccating apparatus [for liqu ids, em u lsion s, ju ices, etc.]. W . S. Bo w e n (U.S.P. 1,774,350, 26.8.30.
Appl., 8.5.28).—The casing of a spray-drying apparatus is formed of permeable material and is operated under slight vacuum so th a t cool dry air is drawn in and prevents any contact of liquid material with the walls.
B. M. Ve n a b l e s.
F ilters for air or other g a ses. A. Sc h i r p Ges.
m.b.H . (B.P. 342,455, 9.12.29. Ger., 26.10.29).—The filter elements are in the form of panels attached a t one end to a vertical chain conveyor. Methods of forming seals between the panels and between them and the framework are described. B. M. Ve n a b l e s.
Apparatus for filtering air or other gases and for cooling or heating air, or other gases, or liquids.
J. Og d e n (B.P. 342,292, 22.10.29).—An apparatus of the type having screens th a t are kept wet by sprays of water or other liquid is provided with a filter submerged in the sump through which the used liquid is drawn by the circulating pump. The screens (for gas) are free to swing or are arranged in the form of a perforated continuous band. B. M. Ve n a b l e s.
B r itis h C h e m ic a l A b s t r a c t s —B .
Cl. XI.— Fu s l; O U a ; Ta b ; i t o a a i x Oil s. 323
Apparatus for precipitation of dust [from gases].
A. E. Da v i s (B.P. 342,439, 30.11.29).—A separator of the laminar flow type having parallel plates of A-shape is provided with slits a t the lower edges of the plates through which the dust m ay drop out.
B . M. Ve n a b l e s.
T reatm ent of furnace g ases. J. G. Co u t a n t, Assr.
to W. C. Dr a k e, E. B . Pr i e b e, and H. Bu c h e r t- ( U .S P .
1,773,954, 26.8.30. Appl., 8.9.28. Fr., 21.9.27).—An apparatus for the simultaneous removal of dust and recovery of waste heat is described. B . M. Ve n a b l e s.
Preventing condensation of m oistu re from flue gases. G. G. Sc h m id t, Assr. to Ca r r i e r En g. Co r p.
(U.S.P. 1,773,870, 26.8.30. Appl., 3.4.28).—An air heater is operated efficiently in th a t the combustion gases are cooled below the dew point, but condensation in the flue is prevented by admixture of some of the heated air. B. M. Ve n a b l e s.
M anufacture of p ressu re g ases from liquefied gases at th e place of consum ption. Production and consum ption of com pressed g a ses. Ges. f. In d u s t r i e g a s v e r w e r t u n g m.b.H . (B.P. 342,423 and 342,527, [a] 21.11.29, [b] 3.2.30. Ger., [a] 5.1.29,
[b] 4.2.29).—(a) Liquefied gas is withdrawn from a container at a moderate pressure, its pressure is raised while still liquid by a pump, and it is then vaporised.
A piston attached to the ram of the pump may be operated by gas a t moderate pressure withdrawn from the upper p art of the storage vessel, (b) Liquefied gas (carried on a vehicle) under moderate pressure is delivered as high-pressure gas by the method described in (a), the pump being operated by the engine of the vehicle and the heat provided by the radiator water.
I f the gas stored is oxygen it may partly be replaced by air which is compressed, and used as the heating medium for the outgoing oxygen, being thereby itself liquefied, and then rectified. B. M. Ve n a b l e s.
Vaporisation of liquid g a ses. Ge s. f. In d u s t r i e g a s v e r w e r t u n g m.b.H. (B.P. 342,597, 31.3.30. Ger., 5.4.29. Addn. to B.P. 287,909; B., 1929, 501).—The process described in the prior patent is modified by having more th an one container: when one is emptied as far as possible into consumers’ vessels the residual gas in it is admitted to a full container to increase the pressure and number of heat-conveying molecules therein. If the containers are mounted on a motor vehicle the heat of the cooling water may be used to aid vaporisation.
B . M. Ve n a b l e s.
Separating the constituents of gaseou s m ixtu res.
C. C. Va n Nu y s and J. L. Sc h l i t t, Assrs. to Ai r Re d u c t io n Co., In c. ( U .S .P . 1,774,462, 26.8.30. Appl., 23.10.26).-—In, e.g., the separation of air, liquefied air is rectified in a prim ary rectifier so as to produce pure oxygen. The top effluent is mixed with additional air, recompressed, reliquified a t a rather lower pressure than before, mixed again with some of the original liquid air.
and rectified in an auxiliary tower so as to produce pure nitrogen. The liquid product from the auxiliary is introduced into the primary rectifier. B. M. Ve n a b l e s.
Refrigerant. J. G. Da v i d s o n, Assr. to Ca r b i d e &
Ca r b o n Ch e m i c a l s Co r p. (U.S.P. 1,765,211, 17.6.30.
Appl., 7.4.27).—A mixture of a substance of the formula
C„H2„+ iR , where R is hydrogen or a halogen, with a t least 20% of vinyl chloride is claimed. Methyl chloride is specifically claimed as the second constituent.
A . R . Po w e l l.
R efrigerators. Soc. An o n, p o u r l e Co n s e r v a t i o n In d u s t r i e l l e d u Po is s o n, and J . E. W. Re e h ( B .P .
342,896, 4.2.30).
Furnace fronts. J. Ho w d e n & Co., Lt d., and W. H . Ho w d e n (B.P. 342,571, 8.3.30).
Lubricating and liquid seal sy ste m s for grinding m ills . E. F. St i m s o n (B.P. 342,568, 6.3.30).
P yro m eter tu b es.—See V III. H eat-conducting bond.—See IX. L ubricants.—See X II.
II.— FU E L ; G AS; T A R ; MINERAL OILS.
F usain. S . W. Pa r r, H . C. Ho p k i n s, and D. R . Mi t c h e l l (Ind. Eng. Chem. [Anal.], 1931, 3, 64—65).—
Proximate analyses of 11 samples of fusain from different parts of Illinois and of the total coal substance from the same faces are given. The fusains had an average volatile m atter of 20-44%, the values being 15—20%
lower than those of the total coal. Sulphur values (0-75—8-18%) followed rather closely the ash values (4-45—18-90%) and the unit coal B.Th.U. values (14,635—15,100) were slightly higher than those of the total coal (14,039—14,705). E. H . Sh a r p l e s.
D evelopm ent of D akota lign ite. IV. Critical oxidation tem perature of lig n ite. W. C. Ea t o n, G . A. Br a d y, A. W. Ga u g e r, I. La v i n e, and C. A.
Ma n n (Ind. Eng. Chem., 1931,23, 87—93 ; cf. B ., 1931, 97).—The methods of Wheeler and of P arr and Coons
( B ., 1925, 195) for studying the ignition tem peratures of coals have been adapted for a study of N orth Dakota lignites from different localities. No material difference in the carbon dioxide index and critical oxidation tem perature was apparent, bu t these properties are affected by moisture content of the sample, size of particles, rate of gas supply, and previous history of the lignite. Drying of the lignite by the Fleissner process does not materially affect the carbon dioxide index and critical oxidation tem perature beyond the effect due to decreased moisture content. H . S. Ga r l i c k.
M acroscopical exam ination of coal deliveries.
C. C. Ca r p e n t e r (Gas World, 1931, 94, 79—83).—The application of macroscopical methods as an aid in the selection of coal for gasworks’ purposes is discussed.
The distribution of cannel, durain, clarain, vitrain, and fusain, and of the ash-forming impurities such as slate and clay shales, calcareous strata, stony and earthy m atters in the coal, and the size, colour, and texture of the resulting coke are noted. The presence of large quantities of. durain makes the coke friable and inco
herent, whilst clarain and vitrain enhance the coking qualities of the coal and give high gas yield s; the presence of fusain, which is non-coking, is undesirable, and cannel, though increasing the gas yield, exerts deleterious influences on the coke. The presence of the various ash-forming impurities will, in general, affect adversely the quality of the coke. C. B. Ma r s o n.
C hem ical con stitu tion of coal. W. A Bo n e
(J. Roy. Soc. Arts, 1930, 79, 77—95).—A lecture.
B r itis h C h e m ic a l A b s tr a c ts — B .
3 2 4 Cl. I L — Fu e l ; Ga sj Ta r ; Mi n e r a l Oi l s.
P yritic oxidation in relation to spontaneous com bustion of coal. I . Miy a g a w a (Mem. Coll. Eng., Kyushu, 1930, 5, 295—397).—Experiments showing the importance of pyritic oxidation as a promoter of spon
taneous combustion are described in detail. Pyrites and marcasite from different sources differ in their absorptive capacities for oxygen, but, in general, marcasite, which is easily crushed, oxidises the more readily. When freshly powdered pyrites is treated with dry oxygen, a t the beginning the reaction is vigorous, but the rate of oxidation decreases with time ; oxidation may be increased by introducing water, which acts as a catalyst. Oxidation of the pyrites produces ferrous sulphate and sulphur dioxide, the last-named being adsorbed on to the surfaces of the pyrites, thereby limiting further oxidation; if this adsorbed sulphur dioxide is removed by water, oxidation again occurs.
The oxidation of pyrites is dependent on its surface area, and hence on its degree of fineness. An appar
atus is described in which the rise of temperature, due to pyritic oxidation, is measured by a thermopile, and its use is recommended to determine the liability of coals to spontaneous combustion. The capacity of a coal for adsorbing sulphur dioxide is of greater impor
tance than its ease of oxidation in determining its liability to spontaneous combustion. I t is concluded th a t (1) pyritic oxidation is not represented by the commonly accepted equation 2FeS2 + 7 0 , -f- 2H 20 = 2FeS04 + 2II2S04, but by FeS2 + 3 0 2 = F eS 04 - f S 0 2;
and (2) coals containing pyrites which are stored in heaps are most liable to spontaneous combustion during
wet weather. C. B. Ma r s o n.
Determ ination of the sw ellin g pressure of coals.
II. N e d e l m a n n (Brennstoff-Chem., 1931, 12, 42— 43).—
The coal (120 g.) is charged into a cylindrical steel crucible (80 mm. in d ia m .; 105 mm. high) provided with a close-fitting piston, which is connected by means of a lever arm with a hydraulic recording manometer.
Between the coal and the piston is a perforated disc of refractory material. The crucible is heated by means of a Meker burner to 700—900° (900° a t the bottom of the crucible). The swelling pressure is recorded, and the amount of the swelling, or subsequent shrinkage, can also be measured. Concordant and reproducible results are obtained. A. B. M a n n i n g .
D ry cooling of coke. J. R u d e (Engineering, 1930, 130, 543—544).—By the dry-cooling process the sensible heat of the coke is recovered; bu t it is also claimed th a t the quality of the coke is improved, owing to its freedom from moisture and breeze. The main objection to the general adoption of the dry-cooling principle is the costli
ness of the plant. Descriptions are given of the Sulzer and Collin methods. I t is suggested th a t the cost of the process might be reduced by sacrificing part of the steam production (by discharging the coke from the cooler at a higher temperature than the usual 250—300°) and by substituting steam for inert gas as the cooling medium. C. B. M a r s o n .
T he cracking process in the gas-m ak in g industry.
G: Eg l o f f and J. C. Mo r r e l l (Ind. Eng. Chem., 1930, 22, 1080—1083).—Gas from the cracking process has a calorific value of approx. 1250 B.Th.U., per cub. ft.
and is relatively rich in defines. Tables are given showing the analyses of a number of gases from the cracking process. By the residual oil method of opera
tion, high yields of gasoline, a marketable fuel oil residue, and an insignificant yield of coke can be obtained with a relatively small amount of gas. The operation m ay also be controlled so th a t only cracked gasoline, gas, and coke are produced. The potential value of gas from the cracking of low-temperature coal tars, tar acids, and gas tars is considered. Coke from the cracking process has an apparent d of 0-9—1 -1, a cellular struc
ture exposing maximum area to reaction with steam, and contains 5—15% of volatile m atter with 80—90% of fixed carbon and 0-1—1 -5% of ash, these physical characteristics making it an ideal raw material for the manufacture of blue gas. H. S. Ga r l i c k.
P rob lem s in th e determ ination of unsaturated hydrocarbons in g ases. III. S om e factors in brom ination w ith p otassium brom ide-brom ate m ixtu re. II. S. D a v i s , G . S. C r a n d a l l , and W. E.
H i g b e e , j u n . (Ind. Eng. Chem. [Anal.], 1931, 3, 108—
110; cf. Davis and Quiggle, B., 1930, 357).—Oxygen prevents the quantitative titration of acetylenes and probably of some diolefines by the bromide-bromate method. A method, in which oxygen is excluded as far as possible from the reaction flask, is described and satisfactory results have been obtained with synthetic mixtures of gaseous defines and acetylenes. The preparation of methyl- (b.p. —20° to —18°) and ethyl- acetylene (b.p. 6 -8—8-5°), trimetliylene (b.p. —28° to
—27°), and other hydrocarbons is described. Alumin
ium, nickel, and mercuric salts aid the quantitative titratio n of acetylene, bu t prevent th a t of ethylene.
E. H. Sh a r p l e s.
T reatm ent of w ater-gas tar. A. V. Siv o l o b o v
and L. L. Bo l o t in a (J. Chem. Ind., Moscow, 1930, 7, 1802—1805).—The ta r is dehydrated by distilling off about 6% of its volume, when the residue on keeping separates into an aqueous and a tarry layer, the latter containing about 1 -5% of water. The ta r on fractional distillation yields a series of liquid hydrocarbons, b.p.
70—245° (85%), from which about 20% of naphthalene and anthracene separate on keeping. The residue contains 45% of oils, b.p. 245—350°, leaving a brittle, dark brown tar suitable for the manufacture of lacquer.
The dehydrated ta r thus yields 61-2% of liquid hydro
carbons (containing 35% of benzene and 8% of toluene), 32-2% of naphthalene and anthracene, and 6 -6% of non-volatile residue. R . Tr u s z k o w s k i.
N ew process for the preparation of hydrogen and hydrogen-nitrogen m ixtu res [from coke-oven ga s]. W. G l u u d (Ber. Ges. Kohlentechn., 1930, 3, 211—220).—Introductory (cf. following abstracts). A new process has been worked out by the Gesellschaft fiir Kohlentechnik in which gas from the coking of coal, freed from hydrogen sulphide, is treated with steam a t high temperature and the following change occurs:
CnH,n f hH20 = «CO + (« + m/2)H,. This carbon monoxide-liydrogen mixture is then treated with addi
tional steam and the hydrogen content of the gas is still further increased: CO -f- I I 20 = C 02 H 2. W ith dolomite as catalyst for the second stage the tempera
B r itis h C h e m ic a l A b s tr a c ts — B .
Cl. I L — Fu e l ; .Gas ; Ta r ; Min e r a l Oil s. 325
ture necessary as well as the space velocities were well suited to large-scale operation. A study of the best types of dolomite capable of withstanding the dis
integrating influence of repeated regenerations showed that samples in which the calcium and magnesium were present in equimolecular proportions were the most suitable, and th a t the temperature of 1050° must not he exceeded. The initial stage of the process proceeded satisfactorily in the presence of a nickel catalyst, bu t the sulphur content of the gas caused a loss of activity due to the production of the sulphide. By suitable choice of work ng temperature the catalyst was maintained in an active condition by the oxidation of the sulphide by the steam, which re-formed nickel (oxide). A special grog was used as a support for the catalyst. Many materials tested were found to cause the deposition of soot by direct decomposition of the hydrocarbons and soon became powdery and friable. Soot deposition, which is excessive in the temperature interval 500—
700°, was avoided by rapid heating of the gases through this range following the addition of small amounts of air or oxygen. In 1927 a plant was erected which was designed to produce 400 cub. m. of hydrogen per hr. So successful was the large-scale operation th a t the carbon monoxide content of the final gas was only 0-05—0-07%.
H. Ix g l e s o x.
T he m eth an e-steam equilibrium and its control.
W. Kl e m p t and 17. Br o d k o r b (Ber. Ges. Kohlentechn., 1930, 3, 220—229).—Theoretical. At high temperatures the reaction between methane and steam takes place according to the equation (1) CH4 -f- H 20 = CO + 3H2
—48 • 9 kg.-cal., whilst a t lower temperatures it takes the form (2) CH4 + 2H20 = C 02 + 4H2 —38-5 kg.-cal.
The equilibrium constants for these two reactions have been determined only for a few temperatures, bu t it is possible to calculate their values from those obtained in the reactions CH4 = C + 2H 2 ; C -f- C 0 2 = 2CO ; and C0-(-H20 = C 02-f-H2, which are known over the range 450—1200°. The constants IC p—pcji^•?)n2o/?’co-?5n2 and K"p = y Cir4 • Pn2c?fr>c02 ■ Ph24 are tabulated over the same range, bu t it is emphasised th a t the values of K 'v can only be strictly accurate a t very high temperatures, whilst the applicability of those of K"p is limited to lower temperatures. Calculation of the equilibrium condition shows th a t a t 500° the cracked gas contains CH4 33-3%, H 20 33-3%, CO 8-33%, and H 2 25-0%, whilst a t 940° the composition is CH4 0-505%, H 20 0-505%, CO 24-8%, and I I 2 74-1% , when reaction (1) takes place. A similar table is given in connexion with equation (2). Since in practice an excess of steam would be used, calculations have been made to find the effect of two-fold and six-fold excess of steam on the equi
librium when pure methane is used. The influence is considered of the other constituents on the equilibrium amount of methane present of a gas of the following composition : 10% (CO + C 02), 30% (CH4 + C„H„) '50% H 2, 10% N2. Temperature-composition graphs are given for both reactions (1) and (2) with this mixture.
At about 820° the methane decomposes to give a t equilibrium a gas containing equal proportions of carbon monoxide and dioxide. H. In g l e s o n.
Catalytic conversion of ga ses containing m ethane into carbon m on oxide and hydrogen. K . Ke l l e r
and W. Kl e m p t (Ber. Ges. Kohlentechn., 1930, 3, 230—261).—The reactions studied were (1) CH4 -(- H 20
= C O + 3 H 2 and (2) CH4 + O = CO + 2 Ii2. The composition of the gas used was approx. 2% C 02, 2%
C»IIW, 0-5% 0 2, 6% CO, 26% CII4, 55% H 2, and 8% N 2.
Poisoning of the catalyst by sulphur compounds present in the gas appears to be due to the formation of nickel sulphide, which, at suitable temperatures, can be decomposed by oxidation with steam and thus prevented from deactivating the catalyst com
pletely. Since reaction (1) is endothermic, considerable difficulty was experienced in maintaining the catalyst a t the high tem perature required when pure steam was used. In the large-scale experiments a study was made of the best method of combining reactions (1) and (2) to prepare a hydrogen-nitrogen-carbon monoxide mixture in proportions suitable for the subsequent pro
duction of a hydrogen-nitrogen mixture in the propor
tions 3 : 1 . A vertical furnace of alloy steel packed w ith catalyst was heated externally by gas, and the gas mixture with regulated volumes of steam and air was passed in a t the base of the catalyst. W ith this furnace, which had a layer of catalyst 94 cm. long by 12 cm.
in diam., 6 m .3 of gas, 3 kg. of steam, and 3 m.3 of air per hr. produced a gas containing (%) C 02 2, CO 17, H 2 56 • 5, N 2 24 ■ 5, CI14 traces. The highest tem perature in the tube was 1050°. In the absence of air it was only possible to convert 3-5 m.’ of gas per hr. into a methane-free mixture. Increase in the am ount of steam does not in all cases increase the methane conversion.
In experiments on the carrying out of the reaction in two stages the catalyst was divided into two separate portions. Gas and steam were passed through the first lower-temperature portion and air was added at suit
able intervals along the second length of the catalyst.
I n this way the methane content could be reduced
to 0-03—0-09% when a 3 : 1 hydrogen-nitrogen mix
ture was required. H. In g l e s o n.
T he w ater-ga s equilibrium and its control.
W. Kl e m p t and F. Br o d k o r b (Ber. Ges. Kohlentechn., 1930,3,261—274).—Theoretical. The known values for the equilibrium constant of the reaction C 0 + H 20 = C 02 + H 2 over the range 327—2090° indicate th a t a t higher temperatures the equilibrium is in favour of carbon monoxide-steam. In order to favour the production of hydrogen as low a tem perature as is compatible with suitable reaction velocity must be chosen. The use of catalysts alone does not materially assist in the com
plete removal of carbon monoxide from the gas at temperatures at which it is practicable to work. The theory is discussed of the disturbance of the equilibrium by use of excess of steam and by the removal of the carbon dioxide formed simultaneously with the hydrogen by absorbents such as lime. The pressure of carbon dioxide in the system CaC03-C aO -C 02 limits the tem perature a t which the latter method of disturbing the water-gas equilibrium can be used to an extreme of 600°. In practice lower tem peratures would have to be used. This theoretical study leaves no doubt th a t the removal of carbon dioxide is the more practicable method of achieving a good conversion of the carbon monoxide. Thus a t 550°, to reduce the steam- and carbon dioxide-free gas to the same carbon monoxide
B r it is h C h e m ic a l A b s tr a c ts —B .
326 Cl. II .— Fu e l ; Ga s ; Ta r ; Min e r a l Oil s.
content as th a t produced by the passage over lime, using one volume of steam, requires a volume of steam tw enty times th a t of the carbon monoxide. By using a slight excess of steam in conjunction with carbon dioxide removed a t this temperature the carbon mon
oxide can be reduced to a mere trace. The foregoing considerations are applied to the gas resulting (cf.
preceding abstract) from the action of steam and air on
methane. H . In g l e s o n.
Conversion of carbon m on oxide b y m eans of steam or air into hydrogen or nitrogen-hydrogen m ixtu res. K. Ke l l e r and W. Kl e m p t (Ber. Ges. f.
Kohlentechn., 1930, 3, 274—306).—The disturbance of the water-gas equilibrium by means of substances capable of absorbing carbon dioxide has been investi
gated on a laboratory and also on a larger scale.
In order to combine the function of an absorbent and catalyst in the contact substance various minerals containing iron were examined. The most suitable of these was found to be burnt dolomite, which was able to be regenerated without becoming friable. A working temperature of 480—-500° was found to be the most suitable. The study was continued in an enlarged apparatus capable of producing 10 m.3/hr. of nitrogen- hydrogen mixture. A detailed description of the regen
eration furnaces is given. The gas resulting from the treatm ent contained small amounts of hydrogen sulphide and carbon monoxide. The former could be removed rapidly at 250—270° a t a space velocity of 100—200 litres/hr./100 c.c. over “ Luxmasse.” Carbon monoxide was removed by passing the desulphuretted gas over a nickel catalyst a t 350—400°. H. In g l e s o n.
L arge-scale plant at Zeche Viktoria, Lunen, [for preparation of h ydrogen and h ydrogen - nitrogen m ixtu res from coke-oven g a s]. I—III.
R. Be s t e h o r n (Ber. Ges. f. Kohlentechn., 1930, 3, 306—341, 341—359, 359—362 ; cf. preceding abstracts).
—I. A description is given of the planning and erection of the plant on a scale of 400 m .3 of hydrogen per hr. To prepare hydrogen, coke-oven gas was passed through the plant in accordance with the following schem e:
hydrogen sulphide washer—booster—(with steam) into methane converter—waste-heat boiler—dolomite con
verters—gas cooler—booster—storage. A diagram is given showing the paths traversed by heating gas, air, and steam. The design of each section of the plant is discussed in detail.
II. [With W. Kl e m p t, J. Sc h r o e t e r, F. Br o d k o r b, and E. Cu r l a n d.] Working details are given for the preparation of the hydrogen-nitrogen mixture.
The coke-oven gas entering the plant contained (%) CO, 2-0, C„Hm 2-0, 0 2 0-5, CO 6-5, C H /2 5 -0 , H 2 52-0, N2 12-0; the decomposed steam -air-treated gas C 02 3-0, CO 16-0, CH« 0 -0—0-2, H 2 57-0, N 2 24-0 ; and the final gas H 2 75, N 2 25%, CH* traces. In producing hydrogen the same general procedure was adopted, but since no air could be admitted the main
tenance of the temperature in the first stage necessitated an increase in the external heating and, according to the purity of the gas required, a reduction in the volume of gas passing. I t is possible, however, to convert 60 m.3 of coke-oven gas per hr. w ith a final methane content of 0 -0—0 -2%.
I I I . Calculations of cost of running the plant are based on the use of a plant divided into 5 similar units producing conjointly 10,000 m .3 of hydrogen-nitrogen mixture (3 : 1) per hr., corresponding to 70 metric tons of combined nitrogen per 24 hrs., reckoning 6% loss in the ammonia conversion. The erection and plant costs total R.M. 3,250,000. The total preparation cost of 1000 m .3 of mixed gas is R.M. 27-96. The cost of hydrogen (containing 1—1-5% CH4, 6% N a) would be 3-35 Pf. per m.3, whilst a gas with less than 0-1% CH4 and 6 -8% N 2 costs 3-7 Pf. per m .3 H. In g l e s o n.
Application of the [cracking] p rocess to the m anufacture of h ydrogen -n itrogen m ix tu res from g a ses (e.g., natural g a s etc.) rich in m ethane.
W. Kl e m p t and F. Br o d k o r b (Ber. Ges. Kohlentechn., 1930, 3, 362—368). Cost of the p rocess. R. Be s t e h o r n (Ibid., 368—370).—The process is particularly suitable for use with gases rich in methane, e.g., natural gas, distillation gases from lignite and coal, and the methane fractions from liquefaction of coke-oven gas.
The chemical and economic advantages of the use of a cheap gas rich in m ethane over th a t of coke-oven gas are dealt with. Of the cost of hydrogen-nitrogen mixtures over 60% alone is accounted for in the cost of heating. The firing with a cheap gas of high calorific value would materially reduce working charges. Experi
ments clearly showed th a t definite advantages result from the use of gases rich in methane.
When carried out on the same scale as th a t envisaged with coke-oven gas the cost of 1 m .3 of hydrogen-nitrogen mixture ( 3 : 1) made from practically pure methane would be 1-93 Pf., assuming methane to cost 1 Pf. per m .3 W ith methane a t the price n Pf. the cost is (0 -6n + 1 • 34)Pf. Hydrogen made from the same source (purest gas) would cost (0-74-m + 1-85) Pf., or (technically pure gas) (0-78n + 1 -52)Pf. The use of pure methane would necessitate the enlargement of the dolomite converters by about one quarter. H. In g l e s o n.
Continuous dehydration and d e-oilin g of gas tar.
M . A. Ca b r i e r (Gas World, 1930, 93, 413).—Rapid dehydration and de-oiling of tar, to render it suitable for road-surfacing purposes, is carried out a t Limoges gasworks in a special apparatus, designed to tre a t 2 tons of ta r per 24 hrs. The crude ta r is distilled to the required composition by circulating it, on the thermo- siphon principle, through two communicating columns, one cold and the other heated. The vapour passes through an expansion chamber a t the top of the heating column and thence to a condenser. I t is suggested th a t the same system can be utilised for the treatm ent of other gasworks’ liquors. C. B. Ma r s o n.
R em oval of sulphur frorii brow n-coal tar oils b y treatm ent w ith tar coke. C. St a e m m l e r (Brenn- stoff-Chem., 1931, 12, 43—45).—Tar oils, containing 0-42, 0-46, and 0-72% S , respectively, were distilled over the coke a t 300—600°, both with and without the addition of air or hydrogen. The diminution in sulphur content of the oils, amounting only to 30—35%, was too low for the process to have any technical importance.
A. B . Ma n n i n g.
Extraction of bitum en for purposes of analysis from bitum inous road-m aking m aterials and
B r itis h C h e m ic a l A b s tr a c ts —B .
Cl. I I . — F u k l ; G a s ; T a r ; M n r E R i L O i l s . 327
determ ination of sulphur in bitum en. F. S e e l i g
(Chem.-Ztg., 1931, 55, 145—146).—The constants of a bitumen fluctuate according to the method of dissolv
ing, evaporating the solvent therefrom, and of its complete removal by stirring on a watcr-bath. A standard method is suggested for the last-named pro
cess, in which a vacuum or an atmosphere of nitrogen is employed. Details of an accurate method for determ in
ing sulphur in bitumen by combustion in oxygen are
given. E. D o c t o r .
A pplication of a b rom ine m ethod in determ ina
tion of phenol and cresols. R. D. Sc o t t (Ind. Eng.
Chem. [Anal.], 1931, 3, 67—70).—A method for deter
mining the phenol or cresol content of liquids such as the wastes from dephenolising plants, gas liquors, etc.
is described. An aliquot of the suitably purified material, containing about 0-02 g. of phenol or cresol in terms of phenol, is made up to 200 c.c. with distilled w a te r; 25 c.c. of 25% potassium bromide solution are added and then 10 c.c. of dilute (1 : 1) hydrochloric acid.
The tem perature of the mixture is brought to 25° on a|w ater-bath, 25 c.c. of 0-3% potassium bromate solu
tion are added, and the mixture is kept a t 25° for exactly 1 hr. with occasional shaking. Then 25 c.c. of 20% potassium iodide solution are added, and, after being kept a t 25° for a further 30 min. w ith frequent shaking, the mixture is titrated w ith 0 -liV-sodium thiosulphate. The results for phenol and »»-cresol are not greatly affected by changes in the conditions, but with o-eresol there is a tendency towards high Tesults and with y-cresol towards low results. The above method is an adaptation of the main factors involved in these changes, and it also provides a balance of the errors occasioned by the uneven bromination of o- and p-cresol. The difference between the figures for the sample and blank determination multiplied by 0-0015675 gives the weight of phenol and cresols in terms of phenol.
E. H. Sh a r p l e s.
C atalytic reactions of sulphur com pounds present in petroleum . I. H igh-sulphur naphthas in con
tact w ith nickel and iron catalysts. J. C. Elgin, G. H. Wilder, andfH. S. Taylor. II. Pure sulphur com pounds in hydrocarbon m aterials in contact with nickel catalysts. J. C. Elgin (Ind. Eng. Chem., 1930,22, 1284—1290, 1290—1293).—I. Nickel is more efficient than iron in removing sulphur from naphthas in the vapour phase. Sulphur m ay be completely removed in contact w ith the initially sulphur-free nickel catalyst, but catalytic activity decreases as the process proceeds until a sta.te of constant, definite though reduced, activity is reached. Sulphur removed is converted into hydrogen sulphide. Hydrogen added to the vapour stream increases the extent of desulphurisa- tion by effecting the removal of sulphur not affected by the catalyst in its absence. The percentage of sulphur removed under fixed conditions varies with the naphtha studied, and is due to variation in the nature of the sulphur compounds present. Nickel and iron catalysts do not absorb all the sulphur present under the con
ditions studied. The results suggest th a t removal of sulphur in the presence of hydrogen m ay be due to alternate sulphide formation with the catalytic surface and its reduction by hydrogen, and th at variation in the
ratio of hydrogen pressure to sulphur compound pressure may increase the effectiveness of the catalytic action.
II. Alkyl mercaptans and sulphides undergo a re
action evolving hydrogen sulphide when in contact w ith a nickel catalyst a t the steady state in the presence of naphtha vapour, the mercaptans being removed more readily th an the sulphides. Thiophen was not affected unless hydrogen was added, the catalyst rapidly losing its activity. Addition of hydrogen effects the removal of a larger proportion of propyl sulphide sulphur than when no hydrogen is added. Increasing the ratio of hydrogen to naphtha increases the amount of sulphur removed. The results account for the difference in sulphur removal observed with different naphthas, and indicate th a t those containing relatively large propor
tions of thiophen sulphur are the most difficult to reduce catalytically. H . S. Ga r l i c k.
Effect of tim e and tem perature on the cracking of o ils. J. C. G e n i e s s e and R . R e u t e r (Ind. Eng. Chem., 1930, 22, 1274—1279).—Atmospheric-pressure vapour- phase cracking experiments were conducted on a repre
sentative Midcontinent gas oil. Three sizes of apparatus used were such th a t the time of contact varied from 0-75 to 4800 sec., and the temperature from 430° to 700°, the quantity of oil passing through the apparatus varying from 3000 to 300 c.c. Detailed results are given for a large number of runs, and a study of these shows th a t similar results can be obtained by increases in temperature or time. A tem perature increase of 17° approximately halves the time of conversion. I t is possible to consider time and temperature together as an index, and as this is increased the yield of gasoline increases rapidly to a maximum, which is slightly higher a t the lower temperature, and then decreases slowly.
The properties of the gasoline are the same for a given tim e-tem perature index, and increase of this results in
(а) an increase in the anti-knock value of the fuel, (б) a rapid increase in unsaturation, followed by a slow decrease, and (c) a rapid decrease in the critical aniline solution temperature. Gas yields increase rapidly to a maximum of 60—70% by wt. The gas : gasoline ratio increases considerably with tim e-tem perature and only slightly w ith temperature for a given index. The unsaturated content of the gas increases with temperature a t a given index only under severe cracking conditions.
Packed cracking tubes result in higher coke yields, and recycling experiments show a considerable increase in refractoriness of the charging stock. H . S. Ga r l i c k.
T herm al considerations of [m ineral oil] cracking processes in baths of m olten m eta ls. N. M a y e r
(Petroleum, 1931, 27, 141—142).—The coefficient of heat transfer depends not only on conduction, but also on the sp. heat and sp. gr. of a substance. Comparative figures for various metals are given. The best thermal effect will be obtained when the oil is finely dispersed in molten metal and the time of contact adequately
extended. E. D o c t o r .
Occurrence of h igh er fatty acids in m in eral oil d istillates. E. H o l z m a n n and S. v o n P i l a t (Bren- stoff-Chem., 1931, 12 , 41—42).—The acids and phenols extracted from a spindle oil were distilled under reduced pressure, and the acids in the distillate separated from
B r itis h C h e m ic a l A b s tr a c ts —B .
328 Cl. I I . — Fu e l ; Gas ; Ta r ; Min e r a l Oil s.
the phenols by the method previously described (B., 1931, 7). The acid mixture, representing 0'0125% of the original oil, on cooling deposited crystals which were identified as arachidic acid. A further quantity of fatty acids not yet identified was separated from the liquid portion of the acid mixture. A. B. Ma n n i n g.
M ethane as a m otor fuel. J. B r o n n (Brenstoff- Chem., 1931, 12, 27—29, 45—47).—The methane ob
tained as a by-product in the production of hydrogen by the fractionation of coke-oven gas a t low temperatures forms a suitable fuel for heavy motor vehicles, especially in districts like the Ruhr. The engine requires no modification except replacing the carburettor by a suit
able mixing valve. The exhaust gas contains little or no carbon monoxide, and only 1—2% of unburnt methane.
No deposits are formed in the cylinder and the consump
tion of lubricating oil is lower than with liquid motor fuels. In comparative road tests it was found th a t about 0-9 cub. m. of methane was equivalent to 1 litre of benzol. I t is estimated th a t under suitable conditions the running costs with methane should be about 30%
lower than with petrol. A. B. M a n n i n g .
Knock in internal-com bustion engines and the action of anti-knock com pounds. J. Lo r e n t z e n
(Z. angew. Chem., 1931, 44, 130—136).—Experiments on the combustion of mixtures of hexane and pentane with air in various proportions, and study of the tim e- pressure curves obtained, indicate th a t when knock occurs reactions take place which differ from the normal.
Variation of the position of the ignition spark shows th a t knock is produced only when a wave of incomplete combustion travels through the cylinder, and is the result of the explosion of the intermediate products of combus
tion by a reflected compression wave when it meets the combustion wave. The normal velocity of propagation of the flame is approximately doubled when knock occurs. The production of turbulence in the gas mixture prior to ignition increases the speed of combustion, and under these conditions knock occurs only a t initial pressures greater than 8 atm. If lead tetraethyl be mixed with the fuel before it enters the cylinder knock is not inhibited, but by introducing the products of combustion of the lead compound into the cylinder before ignition of the mixture knock is inhibited a t pressures below 5 atm., whilst if turbulence is set up in the mixture knock does not occur a t pressures below 9 atm. The theory of the action of anti-knock compounds is discussed.
H . F. Gi l l b e.
P rogress toward a uniform m ethod of m easuring detonation [of fuels]. T. A . Bo y d (Ind. Eng. Chem., 1930,22,1301—1302).—The Sub-Committee on Methods of Measuring Detonation of the A.P.I. Co-operative Fuel Research Steering Committee has drawn up specifica
tions covering the essential features of a tentative engine.
Mixtures of n-heptane and isooctane have been adopted to form a standard scale of anti-knock quality, anti
knock values being expressed in terms of an “ octane number,” i.e., the percentage (by vol.) of isooctane necessary in a heptane-isooctane mixture to match the anti-knock value of any given fuel. H. S. Ga r l i c k.
Detonation characteristics of som e paraffin hydrocarbons. W. G . Lo v e l l, J. M. Ca m p b e l l, and
T. A. B o y d (Ind. Eng. Chem., 1931, 23, 26—-29).—The relative knock ratings of 27 paraffin hydrocarbons have been determined in admixture with a commercial gaso
line. Apparently in homologous series the tendency to knock increases with increasing length of the carbon chain, whilst in an isomeric series this tendency usually decreases as the number of side-chains is increased. The successive introduction of methyl groups into a carbon chain of given length also decreases the tendency to knock and by substantially a constant increment per methyl group added. H. S. G a r l i c k .
Catalytic addition of hydrogen chloride to un
saturated hydrocarbons. W . J. P i o t r o w s k i and J.
W i n k l e r (Przemyśl Chem., 1931, 15, 25—36).—The
optimal temperature for the reaction of addition of hydrogen chloride to unsaturated hydrocarbons present (32%) in the products of cracking petroleum lies between 70° and 150°; it is advantageous to commence the process a t 70°, when chiefly secondary chloro- derivatives are obtained, and to complete it a t 150°, when tertiary chloro-derivatives are the main pro
ducts. The reacting substances should be thoroughly dried, as traces of moisture prevent the formation of secondary chlorides. The reaction is best catalysed by active charcoal saturated with zinc or stannic chloride; these catalysts are inactivated by sulphur- containing substances, which should previously be removed by partly poisoned catalyst before actual con
ta c t with the fresh catalyst. The following products were identified: (3- and S-chloro-p-methylbutane, [3- chloropentane, aąd S-chloro-pS-dimethylbutane.
R. Tr u s z k o w s k i.
Synthetic lubricating oils. A. W. Na s h, H. M.
St a n l e y-, and A. R. Bo w e n (J. Inst. Petroleum Tech., 1930, 16, 830—857).—A detailed account of work on the polymerisation of ethylene, already noted (Stanley
B „ 1930, 935).
Acid treatm ent of lubricating d istillates. H. M.
W e i r , W . F. H o u g h t o n , and F. M . M a j e w s k i (Ind. Eng.
Chem., 1930, 22, 1293—1300).—For the treatm ent of solar reduced oil sulphuric acid of 93% concentration is superior to 98% as a reagent for the removal of colour. The first action of the acid produces a deeper colour than th a t of the original oil, bu t thereafter the colour decreases as more acid is added. Oil loss in
creases with increase of acid concentration. The effect of temperature on the treatm ent is not very pronounced.
Using small quantities of acid, the colour change is slight between 15-6° and 48'9°. For larger volumes of. acid, low temperatures produce better results if the viscosity of the oil is reduced with a light oil. Oil loss does not change with variation of temperature. As the volume and concentration of the acid increase, the A.P.I.
gravity increases and the viscosity and refractive index of the finished oil decrease. The heat of acid- treating reaction and change in gravity are directly proportional to the oil-treating loss, and are practically equal for all concentrations of acid. The acid consumed during the reaction is not proportional to the colour removed. The oil is not appreciably changed as a con
sequence of the action of the acid.
H . S . Ga r l i c k.
