US1207381A - Method of dehydrating and refining hydrocarbon-oils. - Google Patents

Description

E. l. DYER.

METHOD OF DEHYDRATING AND REFINING HYDROCARBON OILS. APPLICATION FILED MAR- 5,1913.

'1 07,381 I Patented Dec. 5, 1916.

2 SHEETSSHEET l- WITNESSES:

QQ/ZW/ E. l. DYER.

METHOD OF DEHYDRATING AND REFINING HYDROCARBON OILS.

APPLICATION FILED MAR 5 1913.

2 SHEETS-SHEET 2- Patented Dec. 5, 1916.

INVENTOR 6. :5. Ja

ATTORNEY W/T/VESSES: I

ERNEST I. DYER, F OAKLAND, CALIFORNIA.

METHOD OF DEHYDRATING Specification of Letters Patent.

AND REFINING HYDROCARBON-OILS.

Patented Dec. 5, 1916.

, Application filed March 5, 1913. Serial No. 752,093.

' To all whom it may concern water in an emulsified form,

Be it known that I, ERNEST 1. Down, a citizen of the United States, residing at Oakland, in the county of Alameda and State of California, have invented certain new and useful Improvements in Methods,

of Dehydrating and RefiningHydrocarbon- Oils, of which the following is a specification.

While the hereinafter described method is applicable to the treatment of hydrocarbon oils generally, the same is more particularly adaptable to those Californian petroleums which contain considerable quantities of which cannot be readily and economically separated from the oil by settling, moderate heating, blowing with air, or by the'application of other well known means usually resorted to for such purposes. These oils are usually dehydrated by evaporation of the water by raising the mixture of oil and water to such a temperature at sensibly atmospheric pressure as Will cause ebullition, driving off the water and the more volatile constituents of the oil simultaneously, in the form of a mixed vapor which is subsequently condensed and the liquid components separated by allowing the water to settle.

The objects of the present invention are to increase the yield of the lighter distillates CV81 that obtained by the methods at present resorted to for dehydrating and refining the hydrocarbon oils without danger of breaking down the lighter fractions, or formation of unsaturated hydrocarbons or other bodies of an objectionable character to such an extent as to involve more expensive chemical after-treatment; to utilize the latent heat of evaporation of the mixed vapors produced on heating the oil under treatment, in such a manner that they shall themselves assist in doing the work of evaporation; to remove any desired proportion of the emulsified water in the crude oil, and

provide against the production of an emulsion of water and light distillates, to successfully treat such petroleums which, when subjected to ordinary cracking processes to increase the yield of light distillates, yield an excessive amount of so-called fixed gases and unsaturated hydrocarbons, resulting in no material gain, through breaking down of the molecules of the lighter hydrocarbons as well as those of the heavier; to provide against subjecting the the usual receiving tanks and thrown away,

ers who use it as a fuel.

-lars per day,

lighter and more valuable distillates to any cracking effect, confining such efiect to the less valuable constituents of the crude oil;

to provide for a simpler, less expensive, an

more economical working of the hydrocarbon oils than is at present utilized in connection with the dehydration and refining of, such oils, while at the same time permitting the method to be carried out as a continuous operation.

Owing to the high latent heat of evaporation of water as compared with the latent heat of evaporation of the constituents of petroleum, allo-f the usual evaporative systems require excessive expenditure of fuels and, owing to the violent ebullition of mixtures of oil and water when certain more or less definite temperatures are reached, under ordinary conditions of operation violent priming of stills is experienced, resultmg 1n considerable masses of the crude oil being carried over with the vapors, contaminating the distillates and rendering their subsequent further refinement expensive and diflicult. This process; also is often accompanied by the production of a very refractory emulsion which ,I :have found to contaln some of the most valuable low-boiling-point fractions of the oil, this emulsion belng ejected" into the condensers through the vap'or pipe, finally settling to the bottom'of being usually under the assumption that it is not only a material without value, but that in addition, being composed of sand and mineral 'matter, it needs to be removed from the oil so that the final residuum may meet the requirements of-custom- In one plant under my observation for some months, this emulsion (which was thrown' away) was actually produced by the plant at the rate of 1000 to 1500 barrels per day. Yet it contained,

by analysis, material which was demonstrated to have a market value suflicient to bring in an income of several hundred dolwhich loss is saved und the prlesent method of treating the hydrocarbon ()1 S. i

In carrying out the improved method, the oil to be treated is subjected in a vessel, closed except'for its outlet and inlet, to a temperature which at normal pressure w1ll drive on the lighter and more valuble distillates without injury, after which they are removed from possible harm ,in further ion stages of the process, where higher pressures and temperatures are used. The oil being thus treated is immediately and Without cooling, passed to a second similar vessel where it is subjected to higher temperature and such pressures above the normal atmospheric pressure as experience indicates to be suitable. Inthis second vessel, conditions of temperature and pressure may be such as to encourage a moderate decomposition of soine of the hydrocarbons still left in the o1 The oil is introduced into both vessels and caused to circulate in a circuitous path in [5 such a way as to cause its temperature to be raised gradually, while its surface, which partakes of practically the same tempera ture as that of the body of the oil at any given point, is in contact with the vapor in the upper part of the vessel, this vapor being normally of a temperature somewhat higher than that of the entering oil and somewhat lower than that of the outgoing oil. The contact of the vapor in the Vessel with the relatively cool oil surface results in a certain amount of condensation of the vapor on the surface of the oil, such condensate being carried bythe motion of the oil into regions of higher temperature where revaporation takes place, producing results analogous to those given by dephlegmators, or column stills. This action tends to promote sharper fractionation and a yield of lighter distil-,

late greater than that obtained by ordinary i5 refining processes without dephlegmators.

By means of the circuitous travel of the oil in'the vessels mentioned, the incoming oil and the outgoing oil are kept widely separated, and of as difierent composition l0 as can be possible when confined in the same vessel. In this way, the outgoing oil carries off fewer of the low boiling-point fractions than it would if the circulation were of a fortuitous character.

In the foregoing there has been mentioned in connection with the carrying out of the method but two vessels and two stages of temperature and pressure, but I do not confine myself to two stages, as vessels may be 9 arranged serially up to any desired number, giving any desired range of pressure and temperatures.

In order that the process shall be under- I stood, I will now describe one application thereof, it being understood that I do not limit myself to this application alone, and that, as above explained, more than two.

stages of pressure and temperature can be used.- In the present example, steam is 9 shown as the primary heating medium, but I do not confine myself to steam alone, it being used as an example by way of illustration.

Any suitable form of an apparatus may be 'tally disposed circulating tubes or pipes i5 employed for carrying out the improved method, but the one illustrated in the accompanying drawings, and formingthe subject matter of a separate application filed by me March 5, 1913, Serial No. 752,092, is an apparatus as actually installed and daily used for treating a large number of barrels of oil per day, is deemed the best for successfully carrying out the improved method, wherein Figure 1 is a diagrammatic view of a side elevation of a plant adapted to carry out the process, employing steam as a primary heating medium, and an emulsified oil as raw material to be dehydrated and p rtially refined, said view disclosing one of the heating vessels, partly broken away, and the companion vessel, the interchanger and the condenser in vertical section. Fig. 2 is an irregular horizontal sectional plan view of one of the heating vessels for the flowing oil. Fig. 3 is a detail View of one of the vertical baflie plates removed from one of the heating vessels. Fig. 4 is an enlarged detail sectional view of one of the headers, taken on the line H of Fig. 2. Fig. 5 is a detail view, on an enlarged scale, of one of the traps, and Fig. 6 is an enlarged detail elevation of one of the headers.

In the drawings, the letters A and B are used to designate What shall be termed heating vessels or cylinders of similar construction, the upper one of which is shown in vertical section. Each vessel is provided adjacent its bottom with a nest of horizonthrough which the heating medium steam, vapor, or any other substance, may pass and circulate. These vessels may also be heated externally by any other suitable means, but as one or both may be operated under pressure, I prefer the method shown, for the sake of safety; but do not limit myself to it alone. The heating tubes A of the vessel A and the tubes B of the vessel B are arranged as shown in the horizontal section in Fig. 2, in this instance being in the form of U-tubes, since this is a convenient form for allowing for expansion and contraction, although I do not confi'ne myself to it exclusively, and are connected respectively to the headers C and C, the respective inlets for the heating agent being indicated at d and (Z and the respective outlets at cl and (i Tubes to any desired extent of heating surface are introduced and divided by a sys tem of vertical longitudinal baflles D, and vertical cross baffles D, in such a Way that the oil which is caused to enter at the open ing a, (see Fig. 2 of the drawings), shall be constrained to follow a tortuous path. as indicated by arrows, in a direction in general parallel to the tubes, up to the point of exit 5. The cross bafiles D are arranged with openings a through which the tubes pass and in which they are supported.

compelled to either traverse the same course as the oil itself or else be dissipated before reaching the outlet. The oil level is maintained so as just to cover. the tubes, so that the oil shall be present in the vessel in relatively small quantities, and its level shall be so low as to prevent its reaching the vapor outlet in case of violent frothing. In this Way the oil is divided up into very small masses and brought intimately into contact with the heated surfaces of the tubes about which the oil circulates, and as it is further caused to flow continuously in a direction parallel to that of the tubes and counter to the direction of flow of the heating medium,

conditions for rapid and'eflicient heat transfer and free liberation of vapor are provided. Under each set of U-tubes I may introduce a perforated agitating pipe f, through which steam is ejected into the vessels to promote still more efiicient heat transing conveyed from a suitable source of supply to said agitating pipes through the conduits E, E. The vessels A and B are proportioned so as to have large liberating surface and ample liberating space above 0 the surface of the liquid admitted therein,

and as the oil is also introduced gradually and in relatively small quantities, it is not all in the same state of ebullition at any given instant, with the result that violent priming is prevented. Further protection is given against violent priming by causing part of the work of evaporation to be done in each vessel, and by the fact that evaporation takes place under pressure in the hotter vessel, it being Well known that evaporation of liquid under pressure can be accomplished more rapidly without priming than when pressure is absent.

As stated, the vessel B is exactly similar 5 in construction to that of vessel A, but the heating medium in its tubes B consists of the mixed vapor from the vessel A under pressure. The vapor from Vessel A is entirely condensed in the tubes of vessel B,

- vessel A being operated under pressure in order that there shall be sufficient temperature head in vessel B to permit of complete transfer of the latent heat of the vapor from vessel A to the liquid contents of ves- -sel B. By this means, the heating medium of fuel.

introduced in the tubes A and vessel A, in this case steam, not only evaporates a quantity of liquid in the said vessel A proportional to the amount of steam supplied from some outside source, but by means of the arrangement described, evaporates almost an equal additional amount in the vessel B. So that with the arrangement shown, neglecting loss of heat by radiation, etc., the original heating medium does, roughly, about twice the work it would do under ordinary conditions. This results in a great saving I wish to lay particular stress on the fact that with an oil containing a considerable quantity of water in emulsion complete utilization of the latent heat in the vapors from A cannot be obtained unless the interior ofvvessel A is maintained at a higher pressure than the interior of vessel B, a higher pressure being maintained in the vessel A by maintaining a higher temperature therein. Operation under varying stages of pressure on this character of oil is therefore necessary to effect high heat efliciency and low fuel cost.

In the particular construction illustrated in the drawing, the hydrocarbon, to be treated, first enters the apparatus through a pipe L leading into an interchanger K from which it passes through the outlet pipe M, the inlet connection E of the vessel B, and into said vessel B, in which it is partially distilled by heat derived from the vapors from vessel A, said vapors from the vessel A passing through d to the header C and thence to the circulating pipes B. Then by means of a pump F, or other suitable means, the oil is forced into vessel A, the pump connecting with a pipe E leading to the inlet u of the vessel A, and with a connection E extending from the outlet 6 of the vessel B, in which it receives its first supply of heat from outside sources.

Pressure is maintainedin vessel A by causing the vapors which condense in the tubes B of vessel B to discharge through the piping B connecting with an automatic trap F i of any approved type or other suitable means which allows "only liquid to pass therethrough.

The particular construction of trap shown comprises a vessel provided with an inlet R and an outlet pipe R, the inlet B being connected with the pipe connection B and the outlet R with the pipe J. At the interior of the vessel is a pot P pivotally mounted as at'A". C designates a valve adapted to cooperate with a valve seat C said valve being carried at the upper end of a rod B, whichis pivoted at its lower end to the pot B The operation of the trap is as follows: Mixed liquid and vapor enter through the inlet R, the liquid causing the pot in the interior to float keeping the valve 0* in' closed position until such time as the accumulation of liquid in the trap has become so great that it overflows into the interior of the pot. When this occurs, the pot fills and sinks, the valve C being opened with the downward movement of the'pot P, and the pressure of the steam or vapor, as the case may be, forces the contents of the pot out through the outlet R With the removal of the liquid from the pot the same is lightened and the pot floats, again closing the valve.

Bya proper relative proportioning of the heating surfaces in the two vessels, the relative amounts of evaporation in the said vessels may be distributed as desired, so that any bodies contained in the raw crude oil which might be injured by the pressure or temperatures obtaining in vessel A shall have been removed in vessel B. In this arrangement of flow, the relatively light crude oil is first subjected to the lowest temperature and pressure of the process, and the relatively heavy partially dried oil is subjected to the highest pressure and temperature of the process, not only forthe reason that the light fractions are more liable to damage by the effect of relatively high pressure and temperature than the heavy portions, but for the additional reason that the heavy portions normally boiling at higher temperatures than the light portions require the application of a higher temperature heating medium to extract their less volatile constituents. While this direction of How is the correct one for relatively light oils containing water in an emulsified form, it is not necessarily the only correct one for heavy emulsified oils containing little volatile matter, and I do not wish to restrict myself to this direction of flow, choosing on occasion with suitable character of oil to reverse the direction. This arrangement may be extended indefinitely and the vapor discharged from the vessel B may be used to heat a third vessel, and so on, each succeeding vessel being operated at lower pressure and temperature than the vessel immediately precedlng. In the present case, the vapor generated in vessel B is withdrawn through the perforated pipe G extended therein and conveyed thereby to acondenser G, Fig. l of the drawings, which condenser may be of ordinary construction and which may use water or oil as a cooling medium, according to circumstances. The vapor passing through the pipe G discharges into a header of the condenser G, which header is divided by a.

' horizontal partition wall 9 into an upper chamber 9 and a lower chamber 72,, and the vapor discharged into the upper chamber 9 escapes therefrom through the U-shaped tubes H situated within the condenser and connected with the chamber g and flows 'therethrough until finally discharged by said tubes into the lower chamber h, from which chamber the distillate and water discharge through the outlet pipe k and are run to suitable tanks (not shown) where the water is drawn off. The water or oil used as a cooling medium enters the condenser through the supply pipe H, circulates within the condenser surrounding the tubes H and escapes therefrom through the outlet pipe I, the flow of the cooling medium being regulated by the horizontal bafi'le J within the condenser.

The heavy distillates' flowing from the vessel B into the pipe J may be delivered into the pipe G with which the pipe J connects, or the same may be directed on the closing of valve j'within the pipe into a branch outlet pipe 74, and by the same delivered to a suitable place of deposit.

Where fuel is relatively expensive, instead of condensing the vapors from the vessel B by means of water or crude oil, I may use them or any of the other vapors for redistilling the crude naphtha or distillate produced by the plant, thus delivering gasolene or similar merchant'able refined materials by continuous operation direct from the crude oil. I may also use a part of these vapors, where under pressure, for the generation of power in pumps, engines, or auxiliary apparatus of the plant; and where exhaust stem is available from engines, pumps, or other steam using appliances, I may also introduce it at suitable points into the heating tubes of the vessels described, there utilizing it for heating purposes; or I may use it in the agitating pipes.

The vapors which condense in the tube of the various "essels may be run to ordinary coolers, or may be caused to give up their heat at any point where temperature conditions render an interchange of heat a trap E or suitable automatic pump re-- ceiver, direct to the steam boilers, not shown.

After the oil leaves vessel A, Icustomarily pass it through an interchanger K, where it assists in preheating the incoming crude oil for the plant. In this case, the crude oil is forced into the interchanger through the supply pipe L and circulating around and flowing over the heated surfaces of the nest of horizontally disposed U-shaped pipes L receives an initial heating, leaving the interchanger through the outlet pipe M, which connects with the inlet of the vessel B. Such of the lighter portions as may pass off as vapor during this preliminary heating escapes through the outlet M of the interchanger andare conveyed to a suitable The flow of this hot oil through the tubes L heats the same to such an extent as to give an initial heating of the infiowing crude oil and by so doing permitting all heat units to be thoroughly utilized, the baffle m within the interchanger K causing the infiowing crude oil to flow in an opposite direction to the flow of the heated oil from the vessel A.

The utilization of the interchanger with 'many oils will perform part of the work of evaporation, and under certain conditions may be employed for redistilling the distillates produces by the various vessels.

The method herein described has been subjected in connection with the mentioned apparatus to the practical test of dehydra tion and refining hydrocarbon oils for commercial use and on a large scale in connection with the oils obtained from the fields of Santa Barbara county, California. The oil .used during this period contained 15% to 30% of water'in an emulsified form of a particularly refractory character. The plant was installed with the expectation that if it should prove successful it would replace the existing plant, which distilled ofi the water from the crude oil together with the light hydrocarbons by means of steam stills operating under atmospheric pressure. The old plant and the new plant were operated simultaneously on exactly similar oil, and the present method proved successful and created a material gain over the old plant then in use. The described method as carried out by the plant as installed may be operated in two or three stages of pressure and temperature, but so far it has been operated in two stages. During this time it has successfully handled several millions of barrels of oil, removing over a million barrels of water from the emulsion in the oil, using about one-third .of the fuel required by the old plant and similar evaporative plants, and its production of distillate from the same quantity and quality of oil as that used by the old plant has been greater, a series of laboratory tests showing that the yield of distillate from the plant has been considerably greater than that obtained in the laboratory by ordinary laboratory methods- Comparison of the yield of distillate produced by the .old plant above referred to with the yield produced by the plant installed according to present systems, shows according to the records of the owner that the applicants system produced a higher percentage of distillate. Another advantage of this process is that the quantity of water required for cooling purposes is greatly diminished ov 'ordinary, practiee,in fact, depending upon the char acter of the oil, the amount of emulsified water contained, the proportion of low boiling point fractions, etc., it is posslble under water as a. cooling medium,a feature of extreme value in many Oll fields located in arid regions.

In carrying out the method, preference is given to the employment of a heat'interchanger for the passage therethrough of flowing treated oil, due to the. fact that the temperature of the infiowing oil is more certain conditions to dispense entirely with .75 the infiowing oil to be treated and the outthan slightly raised prior to the delivery 1 thereof into the finishing vessel and the further fact that such heat units as may be contained in the outfiowing treated oil are utilized and to this extent creating a saving in fuel.

While the described apparatus successfully and practically carries out the improved method of treating the crude oil for dehydrating and refining the same, still the carrying out of the described method is not dependent on the said apparatus as herein shown and described.

The essential steps of the improved method comprises delivering the crude oil to be treated to a closed vessel and causing the flow thereof'in a thin stream through said vessel over heated surfaces, delivering the partially treated oil into a companion closed vessel and causing the same to flow therethrough in a thin stream over surfaces heated from an external source of supply, causing the heated vapors from said oil to pass into the first mentioned vessel for vaporizing the .oil flowing therethrough, and removing the. heavy distillates and vapor separated from the oil within the said vessel and conveying the same to a suitable place of deposit;

Having thus described the invention What is claimed as new and desired to be protected by Letters Patent is 1. The method of treating hydrocarbon oils for the described purpose, the same consisting in causing the oil to flow in relatively small streams in acircuitous path through companion closed vessels, applying to one of said vessels a heating medium from an outside source of supply, heating the oil within the companion vessel by the vapors generated in the first mentioned vessel, removing the vapors generated inthe second mentioned vessel and forcing the oil discharged from said vessel through the first mentioned vessel and maintaining the pressure and temperature in said vessel considerably higher than that of the second vessel whereby the temperature of the flowing body of oil is gradually raised While passing through said vessel.

2. The method of treating hydrocarbon oils for the described purpose, the same 0011- sisting in causing the oil for treatment to flow in relatively small streams in a circuitous path over heated surfaces companion closed vessels, the temperature of the secondvessel through which the oil flows being considerably higher than that of the first vessel, forcing through said vessel the vap'ors from the oil in the second vessel and utilizing the same as a heating medium for the oil in the first vessel, withdrawing the condensate of such vessel, and leading from the first vessel to a-suitable place of deposit the vapors generated therein from the oil passin therethrough.

3. T e method of treating hydrocarbon oils for the described purpose, the same consisting in subjecting the oil in a closed vessel to a temperature which at normal pressure will drive of]? the lighter distillates, causing the oil to flow through said vessel in a thin layer in a circuitous path, removing the separated lighter distillates from within the vessel, thence without permitting the oil to cool passing the same into a second closed vessel where it is subjected to a higher temperature and pressure above normal atmospheric pressure, causing the oil to flow through said vessel in a thin layer in a circuitous path, and forcing the vapors generated from said oil into and through the first mentioned vessel and there utilizing the same as the heating medium for the oil flowing therethrough.

4. The method of treating hydrocarbon oils for the described purpose, the same consisting in delivering the oil within a closed vessel, causing the same to flow through the vessel in a thin layer over heated surfaces, removing from the said vessel the lighter vaporized portions of the oil, leading the oil into a second closed vessel, causing the oil to flow therethrough in a thin layer in a circuitous path over heated surfaces, discharging into said vessel a heating medium from an outside source of supply, conveying the vapors generated within said vessel to the first mentloned vessel and forcing the same therethrough as the heating medium for the oil flowing through said vessel, maintaining the oil within each vessel in a condition of agitation, and removing the condensates of the vapor passing through the first mentioned vessel for the heating of the oil therein.

5. The method of treating "hydrocarbon oils for the described purpose, the same consist-ing in causing the oil for treatment to flow through companion closed vessels, applying to one of said vessels a heating medium from an outside source of supply, heating the oil within the companion vessel by the vapors generated in the first mentioned vessel, removing the vapors generated in the second mentioned vessel, and forcing the oil discharging from said vessel through the first mentioned vessel, the pressure and temperature in said vessel being considerably higher than that of the second mentioned vessel, whereby the temperature of the flowing body of oil is gradually raised as passed'through the said vessels.

6. The method of treating hydrocarbon oils for the described purpose, the same consisting in subjecting the oil in a closed vessel to a temperature which at normal pressure will drive ofi" the lighter distillates, causing the oil to flow through said vessel, removing the separated lighter distillates from within the vessel, thence without permitting the oil to cool passing the same into a second closed vessel where itis subjected to a higher temperature and pressure above normal atmospheric pressure, oil to flow through said vessel, and forcing the vapors generated from said oil into the first mentioned vessel and there utilizing the same as the heating medium for the oil flowing therethrough.

In testimonywhereof I have signed my name to this specification in the presence of two subscribing witnesses.

ERNEST I. DYER.

Witnesses: i

N. A. AGKER, D. B. RICHARDS.

causing the

Images