US2097097A - Process of refining oils - Google Patents

Description

Oct. 26, 1937. w. T. HANCOCK PROCESS 0F REFINING OILS Filed Sept. 23, 1935 @New .. IQ L AUTOR/v51 u@ QQOKMJ Patented ocr. 2c, 1937 UNITED sTATasv PATENT Vori-ica ZCIaims.

'Ihis invention relates to improvements in treating hydrocarbon oils and/or distillates thereof to produce oils of enhanced stability with regard to color and of decreased sulphur and 5 gum content.

The principal object of the invention is to treat petroleum distillates, particularly cracked distillates, either in liquid or vapor phase, by contact with a solid adsorptive material which may or may not have catalytic properties while inthe presence of carbon dioxide.

The invention of thus contacting'hydrocarbonsmay be practiced under superatmospheric pressure while the hydrocarbons are suitably heated to a temperature suiiicient for their vaporization either before or after such contact treatment, but said temperature is below the vcracking temperature of the hydrocarbons.

Heretofore in the treatment of cracked distillates derived from the cracking of oils of California origin, the so-called Gray vapor phase refining process, as illustrated in U. S. Patent 1,340,889 and others, has not been successful in that from observations not only isit found that the gums or polymerized 'products of rening are not reduced, but they are actually increased. In addition, by the application of the above socalled Gray process to California cracked distillates of relatively high sulphur content, no reduction in sulphur occurs so that the distillates still have to be sulphuric acid treated to reduceV such sulphur. As the acid treatment will also remove gums (sulphuric acid being a polymerizing agent), it is clearly no advantage to use the so-called Gray process on cracked distillates of California. origin. f

In the Mid-Continent oil'elds where relatively high sulphur content oils are not common, the so-called Gray process is used to polymerize un- 40 desired unsaturates so that color stability is assured without subsequent treatment with sulphuric acid.

It is, therefore, a. further object of this invention to provide a treatment for petroleum and/or its distillates, whether cracked or not, but particularly for cracked distillates of California origin, whereby undesirable constituents thereof tending to render the treated product of unstablel color are converted and removed from the oil under treatment, either by polymerization or otherwise, and at the same time the sulphur content is materially reduced. This may be accomplished-ether in the liquid phase or vapor phase, by contacting the oil, whether cracked or not, with an adsorptive material of the type of (Cl. ISS-447) fuilers earth while in the presence of carbon dioxide which may be derived from the adsorptive material itself under suitable heat conditions, or may be an addition product such as ue gases or the like.

A diagrammatic flow sheet is furnished which may be used to illustrate the process both in the liquid and vapor phases.

Example 1 describes liquid phase treatment in which, merely by way of illustration and not of 19 limitation, a cracked distillate of California origin such as cracked distillate of gasoline boiling range is drawn from storage I0 by pump II and forced through a pipe 'coil I2 in furnace I3 whereby it is heated by burner I4 to a tempera- 15 ture sumcient for the purpose, from about 300 F, to 500 below the cracking temperature of the distillate, and passes through lines I Sand I6 into the lower part of a treating tower Il, containing a body of adsorptive material I8 held 20 between upper and `lower perforated plates or screens I9 and 20, respectively, which are of well known construction to permit relatively free ow of liquids or vapors, while preventing carrying over of the adsorptive material.

The adsorptive material may be any of the well known polymerizing, decolorizing, and adsorptive clays, such as fullers earth, bentonite, Death Valley clay,-Muroc clay, or the like, which may havecatalytic properties as well as being 30 conducive to hydrogenation, depending on constituents thereof under operating conditions, and the hydrocarbon liquid is passed upwardly therethrough concurrently with a stream of carbon dioxide, or a mixture of gasesvcontaining carbon dioxide, such as flue gases, drawn, for instance, from furnace I3 through line 2| and forced by pump 22 into lines liand I6 to be intermingled with the heated oil and pass through the adsorp- 40 tive material I8.

'Ihe carbon dioxide, or mixture containing carbon dioxide, may be introduced into the heated oil as a cooled gas or at about the same temperature as the oil anda heat exchanger 23 is provided in line 2| to suitably heat or cool the CO2 gas supplied from furnace I3 or from any other source such as through line 24, and the volume of CO2 so introduced to the oil may be varied by simple trial to eiect maximum rening of the 50 oil depending on the type of oil under treatment.

, Flue gases containing about from 5% to-15% of CO2 and about 10% of oxygen havebeen found satisfactory. Steam may be concurrently introduced through une 24. 55

The pressure maintained -on the liquid oil while b eing heated and treated with the adsorptive material and C: may be varied by the setting of a valve 25 to range between 50 and 200 pounds per square inch, and is preferably. about 100 pounds, so that upon reduction of such pressure, to say from about 30 to 50 pounds, certain desired low boiling fractions will be released upon expansion through lines 26 and 21 into fractionating column 28 whence the desired distillate of definite boiling range, such, for instance, as gasoline, will pass through line 23 into condenser 30 and receiver 3|.

Undesired heavy fractions, including converted and/or polymerized products, will be drawn from column 28 through draw-off line 32, while incondensable gases including. any excess CO: will be drawn olf from receiver 3| through line 33, and the gasoline and any water will be drawn of! respectively through lines 34 and 85.

The pressure maintained on the oil in treating tower I1 during operation is preferably such as will prevent substantial vaporization at the operating temperatures in liquid phase treatment, and tower Ilmay be suitably insulated or lagged to prevent great heat losses.

The flow of liquid hydrocarbon through tower Il may be downward as well, but in liquid phase,

treatment an upward ilow is desired to prevent or minimize gas binding in the adsorptive material.

The adsorptive material used may be any one of a number containing varying percentages of SiO-2, A1203, CaO, MgO, NazO, E20, FezO: of the general class of materials used for so-called contact clay refining either in liquid or-vapor phase,

4provided such refining takes place in the presence of carbon dioxide.

What the exact chemical reactions are is not fully known but an improved product is produced over that known by ordinary liquid or vapor phase clay refining an increased color stability and reduced sulphur content.

While the CO2 may be introduced to the contact material with the oil in many modifications apparent to those skilled in the art, it may be desirable under certain conditions of material supply to use an adsorptlve material containing CO2 which is released in the treating tower I1 under suitable conditions of temperature and pressure.

For instance, it has been found that a mineral having the following chemical analysis is suitable for the herein disclosed process:

Percent SiOQ 18.44 Ferm 1.28 Alan-i 6.58 CaO-- 37.35 M80 1.94 NazO 0.96 m 0.22 COQ 29.31 Moisture 3.84

It is not known in what form the CO: is held in the above mixture, or whether all of it is released, but it is believed that part of it at least 1 CO: improved results are scribed.

In Example 2, pipe coil I2 may be considered as a cracking coil for liquid hydrocarbons in which a cracking temperature of about from 700 to 900 F. may be applied to the oil. In this case, the cracked oil is preferably passed through a line 36 into ai vaporizing drum 31, wherein certain tarry heavy fractions are removed, the vapors then going into a fractionating column 38 similar to column 28 where they are cut to a desired boiling range and then passed through line 39 downwardly through the contact in tower I1 in the presence of CO2 introduced through lines 2i and I as before.

In this case the temperatures and pressures in tower I1 will be the same' as before stated, and

obtained, as above de-V liquid polymers, oxidized products, and the like may be continuously drawn off through pipe 40.

Such vapor phase refining of cracked or other material may be conducted by passing the vapors and C02 upwardly through the adsorptive material, and suitable valves, which may be automatic or manually controlled, are placed throughout the system as indicated to regulate the temperature, pressure, rate of flow, etc., `as required, to maintain continuous operation in well known fashion.

In liquid phase refining of cracked California distillates when using a local California clay, known as Muroc treated clay, which shows the following analysis:

Percent SiOa 58.14 AhOv 16.04 Feam" 1.76 CaO 1.70 MgO 2.95 NazO 1.40 KaO 0.63 Loss on ignition 17.50

'in tower I1, the use of flue gases at the rate of the color from 3 N. P. A. to 30+, the octane rating (C. F. R.) from 65 to 71, the initial boiling point lowered from 100 F. to 93 F., the end point lowered from 485 F. to 354 F., and the residual sulphur lowered from 0.720 to 0.464.

Combined with the above results in obtaining a treated gasoline of stable color and superior quality is the fact that the total amount of steam used seems to have been absorbed or converted in the final product, inasmuch as substantially no water appears in the nal product.

As before stated, the full theory of the chemical reactions taking place is not fully comprehended but it might seem that the clay exercises some catalytic effect in combining the CO2 and/or the O and/or the steam in the treating tower to produce the new product.

That some conversion seemingly takes place in the clay is indicated by the fact that about five percent (5%) of a dark colored liquid may be anamorf 56 of the introduced distillate.

It is, of course, obvious that the iiue gases and/or steam may be separately'` directly introduced into the treating tower below the screen 20 with the heated oil which may be supplied directly from the condenser of any well known liquid form through a body of adsorptive matecracking system. In general, the use of ilue gases may bevaried from about 2 to 20 cubic feet per barrel of oil treated and 'such rates may be changed to meet the requirements of any partic-A ular stock treated.

I claim as my invention:

1. In the process of refining oils wherein a stream of cracked gasoline distillate is passed in liquid form through a body of adsorptive material at a temperature of between 300 and about 500 F. while 'under -a superatmospherlc pressure suilicient to maintain said liquid form, the step which comprises: simultaneously passing a stream of nue gases containing free oxygen through'- said vmaterial with said oil.v

2. In the process ot refining oils wherein a' stream ot cracked gasoline distillate is passed in rial at a temperature between 300 F. and about 500 F. while under a superatmospheric pressure suilicient to. maintain said liquid form, the step which comprises: simultaneously passing a stream ot nue gases. containing tree oxygen and steam through said material with said oil.

WHLIAM `THORNHILL HANCOCK. l

Images