US2453060A - Process and apparatus for treating bituminous sands - Google Patents

Description

Nav. 2, 1.948. R. F. .BAU-ER Erm. 2,453,060-

PROGESS'AND APPARATUS FOR TREATING BITUMINOUS SANDS Filed Aug. s. 1944 ...36km N5..

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l Patented Nov, 2, i948 PROCESS AND APPARATUS FOR TREATING BITUMINOUS SANDS Robert F. Bauer and Harold J. Matthews, Los AngelesyCalif., assignors to Union Oil Company of California, Los Angeles, Calif., a corporation` of California Application August 26, 1944, Serial No. 551,364

This invention relates to a process and apparatus for separating and treating bituminous sands and like materia1 into its bituminous and other constituents, one'of the resulting products being composed almost wholly of the bituminous constituents of the material with only a small amount of other matter and the other product be ing composed of the other matter in which remains only a small quantity of bitumen.

simple and economical process and apparatus capable of operation under commercial conditionswhich will enable a maximum amount of bitumen to be recovered from the material treated.

Another object is to provide a simple and effective means for causing the disintegration of the sand and the separation therefrom of the bituminous products.

We have discovered a process by which bituminous products may be readily and efficiently recovered from bituminous materials in continuous agglomeratlon and flotation steps, wherein a pure bitumen is the resulting product leaving clean mineral matter as a residue. y

The process of our invention may be readily understood by reference to the attached schematic drawing illustrating one modiilcation of the same.

Rich bituminous sands are continuously fed into tar sand hopper I, by means of a continuous series of trolley cars similar to that designated as 2. This series of trolley cars operates on a circular narrow gage track, such as that designated as 3. The bituminous sands are placed on the trolley cars by means of trucks, located at the arc opposite tar sand hopper I, and when the trolley cars are full to capacity the rcars are moved around the circular track motivated by electric motor 4. When bituminous sands on the moving trolley cars contact scraper blade 5 the sands are scraped oi and cascaded down into hopper I thus providing our apparatus with a continuous feeding device. The bituminous material cascading down through hopper I enters rotary pulper and kminous material during its passage through launder 1 is contacted by a heating and diluting medium `by the introduction therein of hot water from hot water heater B vilal lines 9 and I0 and controlled by valve II. The bituminous material' entering rotary pulper 46 is heated therein by means of the aforementioned hot water and disintegrated therein by means of agitation effected by the rotation of the pulper and blades I2 at'- tached to the walls of the pulper, the combined eilect being to pick up and drop one lump of tar' sand feed upon another and thus bring about disintegration. The pulper is rotated by means of gear I3, which could be any suitable driving mech-y anism, which is connected to any suitable motor, not shown here. The bituminous material during its passage through launder 1 and prior to its entrance into the rotary pulper and conditioner B is contacted with a conditioning reagent,y such as sodium silicate, sodium carbonate or other reagent as described later. This reagentxisin-` troduced, 4preferably as a concentrated :aqueous solution, into launder 1 from tank 'I4 via line I5 and controlled by valve I6. `Several changes are effected in the mixture conditioned in rotary pulper 6. Such changes are brought about `by the cumulative effect of the numerous variables of time, agitation and/ or abrasion, temperature and concentration of reagent. Regarding the change in thev character of the bituminous material effected in this primary conditioning several things may be said to occur. Of primary importance, however, is the quite ilne division and dispersion of oil particles. In the process of finely dividing the oil` particles, entrained sand is released from the oil matrix. If clay is present, as it is to some extent in practically all sands it is thus freed from the oil and subsequently may be held in the water either ina ilocculated or a dispersed form. Whether the clay will be ilocculated or dispersed is a function of the inherent chemicals in the particular sand and the water used. In either case however, it is not critical from the standpoint of the subsequent flotation step, but may be of importance in the event that it is found desirable to recycle the water used in the` subsequent ilotation step. In this case, it may be found desirable to add a small amount of a reagent to effect flocculation of the clays which were previously dispersed therein. Such a reagent as sodium chloride might be used. for this purpose or any one of a number of other reagents known to nocculate 'clays might also be employed.

conditioner 6 by means of launder 1, 'I'he bltu- 55 The hot disintegrated bituminous material and here.

nous sand and. water cascading down throughv nely divided oil particles move through pulper 6 as described above and enter screen enclosure i1 in stationary housing I9 via channel I9. Screen i1 and channel i9 rotate in conjunction with rotary pulper 6, the screen acting as a sifting device whereby the disintegrated bituminous particles and nely divided oil particles fall through the bottom of the screen and down into launder 20.

The large rocks and pebbles, i. e. foreign matter too large to pass through the screen mesh pass horizontally along the screen and out through opening 2i and down through launder 22 to be disposed of in any desirable manner, not shown rlhe hot mixture of disintegrated bitumila under is known as pulp in the bituminous sand industry. The pulp in launder 20 is again conditioned/this time with an oil solvent, such as kerosene' or other solvent as described below, which is introduced therein from tank 23,via1ines 24 and 25 controlled by valve 26. This mixture consisting of hot bituminous pulp, and kerosene in launder 20 is then introduced into secondary sand conditioner 21, which is provided with a mixer 29 equipped with impeller blades, and weir 29 for maintaining a liquid level therein. The mixer 28 is rotated by meansof gear 3D which may be any suitable driving mechanism, connected to any suitable motor, not shown here. The mixture in secondary sand conditioner 27 is conditioned by means of the introduced solvent and the agitation provided by the swiftly revolving shaft and impeller blades, so that the tar and solvent are aerated and tend to separate by notation from the sand and water.

AThe addition of the solvent to the above pulp will effect a coagulation or agglomeration of the dispersed oil particles. The solvent will also dissolve the oil or tar present in the bituminous sands and reduce its viscosity.and density. The thus conditioned mixture vcomprising agglomerated oil,

solvent, sand, sodium silicate, and water in the secondary sand conditioner 21 is introduced into primary flotation cell 3| via launder 32. The flotation cell may be any one of the recognized notation cells used in the mining industry, but is preferably one with screw lifts such as 33, positioned on the bottom of the flotation cell, and operated by means of gear 34 which is motivated by any suitable means, not shown here, so as to operate in such a manner that the sand particles are carried up the inclined bottom surface to outlet 39 as shown in the drawing, A water level is maintained in the flotation cell preferably below outlety 39, by means of overflow 35 which may also be controlled by valve 36. Hot water is introduced into the flotation cell from hot water heater 8 via lines 9 and 31 and controlled by valve 38. The conditioned pulp mixture entering primary flotation cell 3l through launder 32 deposits the solvent and agglomerated oil upon the water surface therein in the form of a froth and the heavy mineral particles of sand sink to the bottom of the cell and deposit on rotary screw 33 which continuously removes the sand particles up the inclined bottom of the cell and cascades it down through launder 39. When the agglomerated oil-solvent frotnreaches the level of skimmer housing 40, skimmers 4| in skimmer housing 40 are revolved by means of gear 42 which ls motivated by any suitable means, not shown, through the froth and pick up the top surfaces and cascade same down through launder 43. The sand released from the previously prepared pulp, which may still contain a certain percent of bituminous material. is deposited on screw conveyors 33"and cari-led up the bottom of said flotation cell, as aforementioned,

and is then introduced into tertiary sand conditioner 44, provided with mixer 45, Weir 46, and gear 41 similar to those described in secondary sand conditioner 21. The sand slurry in tertiary sand conditioner 44 is diluted with Water and solvent if desired, and is again violently agitated as in secondary sand conditioner 2l. After this violent agitation the aerated slurry is introduced into secondary notation cell 50 via launder 5l, wherein the clean mineral matter is precipitated upon screw conveyor 52 which is rotated by gear 53 connected to suitable motivating means not shown, and the bitumen froth floated on the water surface as described in primary notation cell 3i. Revolving skimmer 54 in housing 55 removes the bituminous froth from said water surface and cascades it down the launder `56. The mineral matter or tailings free of bitumen is removed from secondary flotation cell 50 by means of line 51 and deposited on tailings dump. The oil froth in launders t3 and 56 is diluted by additional solvent, preferably a petroleum fraction, introduced into the launders from tank 23 via lines 24 and 58 and through line 59 controlled by valve 6l) and line 6I controlled by valve 62, respectively. The diluted bituminousfroths in lines 53 and 56 are blended together and introduced into mixing tank 63` bottom of said thickener where rake 68 will scrape the fine tailings into line ll which leads to the tailings pile. The bitumen and petroleum fraction in thickener 56 is removed from the top of the thickener via line l2 and pumped to any suitable site, not shown, wherein the bitumen is separated from the added solvent, for example by distillation. If desired the separated solvent may be recirculated to tank 23.

In the process as illustrated, hot water is introduced into 'launder 'I and therein contacting the bituminous sands to act as a diluent and a heating-medium for the purpose of furthering the disintegration of the bituminous sands. The degree of dilution of the bituminous material with hot water in this step plays a very important part in this process. Therefore, when the amount of hot water introduced therein is limited to amounts insufficient to raise said bituminous material to the proper temperature, steam is introduced into said launder by means of line 'I3 controlled by valve |4`in order to correct this deciency. Steam may also be introduced into rotary pulper 6 by means of line l5.

A proposed modification of the above process is the substitution of ari independent sand conditioner similar to sand conditioner 21 instead of using pulper Bifor the dual purpose of pulping and primary conditioning.

1clean tailings from attacco Conditioning time-Pio' sec. to 30 minutes.

Degree of agitation-fairly violent to very violent. Y

Temperature of pulp-130 F. to 210 F. Goncentration oi reagent-w10 lbs. per ton of tar sands. Tar sand-water ratio-:1 to 1:3 -by weight.

"The optimum operating conditions inf secondary conditioner 2l, i. e.- pulp retention, temperature,

type of agitation, and quantity of solvent used should also be determined for each particular tar sand. Ultimately, however, the magnitude of each of the above factors should lie within the following limits:

Retention period-10 seconds to 30 minutes. Temperature of conditioning- 100v F. to 212 F. Type oi agitationfairly violent to very violent. Quantity of solvent-.0l lbJbbl. of tar to 700 ibs/bbl. A Quality of solvent-(see following discussion).

Regarding the characteristics to be desired in the solvent to be used we set forth the following:

i. A low viscosity to minimize the viscosity of the resulting mixture and thereby facilitate the settling of solids and/ or mineral matter from the froth. i

25A lowspeciiic gravity to minimizetthe specie gravity of the resulting .mixture and thereby facilitate the settling of solids and/or mineral matter from the froth.

3. A high solvent power, or ability to dissolve the tar in a minimum amount f solvent. y l i. A tendency to maintain or improve the hydrophobic condition of the tar, and also to maintain or improve the hydrophillic condition of the sand, so as to make the sand more easily water.- wettable, and the tar more susceptible to ilotation.

As solvents, petroleum fractions such as cleaners solvent, kerosene and gas oil distillates have been used successfully.

eiiciently than others. Aromatic type hydrocarbons have greater solvent power for most tars than do the non-aromatic hydrocarbons, so for many operations benzene, toluene, coal tar fractions. and aromatic extracts from petroleum fractions, such as Edeleanu extract from kerosene and the like,are very useful. Non-hydrocarbons, auch as organic oxygen and sulfur compounds including alcohols, ketones, mercaptans, suldes, thiophenes, and the like are excellent. Basic organic compounds such as the nitrogen bases, espebe within the following limits: l

ing reagents alkaline compounds such as metal hydroxides ory 6 In the description oi thedrawing sodium' silidesignated as the cate and sodium carbonate are conditioning reagents, but the invention is not limitedto theuse of these two. Other conditionwhich may be used are inorganic metal salts of a lstrong base and a weak acid. Compounds of the alkalimetals. sodium, potassium, lithium and caesiurn, especially sodium, are greatly preferred. In many instances however, we may also use compounds oi other metals such as the alkaline earth metals calcium, barium and strontium and other heavy metals. Ammonium hydroxide may also be used. The preferred salts oi these metals are those having polyvalent anions, especially the carbonates and silicates. The phosphates are also excellent, and the pyrophosphates, 'v

phosphitac, sultes, arsenates. suldes, and the like may be employed.

The foregoing description not to be taken as limiting our invention but only as illustrative thereof since many variations may be made by those skilled in the art without depart- .ing from the scope of the following claims.

We claim:

l. Apparatus for treating bituminous sands which comprises, in combination: a rotary pulper and sand conditioner provided with means for introducing tar sands therein, means for introducing hot water and steam, means for introducing conditioning agenta'means for pulverizlng and ,agitating the bituminous sands, and means for segregating conditioned pulp from foreign material; g. secondary sand conditioner provided with means for introducing pulp therein, means for introducing an oil agglomeration medium, and means for agitating the pulp and agglomerating medium; a flotation cell provided with means for introducing sand particles and agglomerated oil, means for introducing water, means for controlling water level, means for removing sand particles, and means for removing agglomerated oil;

a tertiary sand conditioner provided with means It ls to be noted, however, that certain solvents perform much more means for o removing for introducing sand particles containing oil, and means for agitating the sand and oil particles; a secondary notation cell provided with means for introducing the agitated sand and oil particles, the clean sand particles, means for removing the clean oil particles; and means for mixing alight petroleum traction with the oil removed from the two flotation cells; means for mixing the, light petroleum fraction and the recovered oil; and means for removing the light petroleum fraction and recovered oil from the ne sand tailings.

2. A process for treating bituminous sands t0 separately recover the bitumen and the bitumenfree sand therefrom which comprises introducing bituminous sands, conditioning reagent, hot water and steam. into a rotary pulper and sand conditioner having means for agitating and pulverizing said bituminous sands, disintegrating said bituminous sands therein and thereby forming a pulp comprising disintegrated bituminous sands and water; segregating foreign matter from said pulp and cascading said pulp into a secondary sand conditioner having means for agitating said pulp, introducing into said secondary sand conditioner a solvent adapted to dissolve bitumen, agitating and aerating the mixture oi pulp and solvent; cascading the agitated and aerated mixture of pulp and solvent into a primary dotation cell containing water;

in said primary dotation cell; cascading bituoi our invention is skimming a froth comprising bitumen and solvent from the surface ci the water 'Ifhe following references are of record in the 15 e of this patent:

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