US1862942A - Method of distilling crude oil - Google Patents

Description

T. J. RYAN METHOD OF DISTILLING CRUDE OIL kJune 14, 1932.

Filed June ll 1927 3 Sheets-Sheet ASW wmv

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T/omas Qfyaw T. L RYAN 1,862,942.

3 Sheets-Sheet 2 31a/vanto@ mams Filed June l, 1927 METHOD OF' DISTILLING CRUDE OIL June 14, 1932.

June 14, 1932. T J RYAN l 1,852,942

METHOD OF DISTILLING CRUDE OIL Filed June l, 1927 3 Sheets-Sheet 3 woenfoz Patented June 14, 1932 PATENT OFFICE THOMAS J'. RYAN, OF BURNETT, CALIFORNIA METHOD OF DISTILLING CRUDE OIL Application filed .Tune 1, 1927. Serial No. 195,796.

rlhis invention relates to a novel and improved method of distilling crude oil.

The most common way of distilling crude petroleum oil for the production of gasoline and other light products is by what is known as the shell still method'. The objection to this method is, first, that the installationis very costly, estimated at one hundred dollars per barrel of crude oil charging capacity; i0 second, that the distillation is very slow; third, that all the light products, such as gasoline, naphtha and'burning or lamp oils must be re-run in steam stills and treated in agitators with acid and causticsoda before 5 a finished product is produced; fourth, owing to the necessary processing and re-running, this operation is very costly from a standpoint of fuel use under boiler and stills.

The object of my invention is to provide a Z process by means of which crude oil may be treated practically without pressure and at p very low temperatures, whereby the gasoline,

naphtha and kerosene vapors may be liberated without heating the oil to cracking temperature, and thereby enabling products of proper color to be directly obtainedwithout further treatment or re-running.

ln the accompanying drawings,-

Figure 1 is a diagrammaticplan view of an oil distilling apparatus for carrying out my invention.

Figure 2 is a side elevation of one of the stills.

Figure 3 is a. front end elevation of one of the stills.

Figure 4 is a vertical longitudinal section through the still.

Figure 5 is a vertical transverse section on line 5-5 of Figure 4.

Figure 6 is a diagrammatic sectional view of portions of one distilling unit of the apparatus.

In carrying my invention into practice, I preferably employ a distilling apparatus comprising duplicate primary and secondary distilling units A and B which are substantially alike in character, diering in the details hereinafter described. Each of these units comprises apipe still 1, heated in any suitable manner and having a heating or combustion chamber in which is arranged a pipe coil 2 having the inlet and outlet ends 3 and 4. The inlet end 3 of the pipe coil 2 of the pipe still 1 of unit A is connected with a crude oil feed pipe 5 connected with a supply pipe 6 leading from a suitable storage tank. In pipe line 6 is arranged a crude oil charging pump 7 for forcing the crude oil through the coil 8 of an exchanger 9 under a desired low pressure to the coil 2 of still 1. rllhe outlet end 4 of the coil 2 of each pipe still is connected with an outlet pipel 10 leading therefrom to an expansion tower 11. In each pipe 10 is placed a suitable type of recording temperature gauge bulb 12, where- @5 by the Stillman may readily see at all times the temperature of the heated oil passing from the stills to the expansion towers 11.

The crude oil passing through the primary still 1 of unit A is heated to a maximum temn erature not greater than 300 F. to 350 F., while the oil heated in the secondary still of unit B is heated to a maximum temperature not exceeding 400 F. to 450o F.

Each expansion tower 1l is of suitable dimensions and is designed to receive the heated oil from its still. The pipe 10 through which this heated oil passes enters through the side of tower 11 four feet from the bottom and terminates in an upwardly extending discharge portion of nozzle 13. This nozzle 13 has its upper end terminating a consider'- able distance below the horizontal center of the tower, and ordinarily extends abouty seven feet above the bottom of the tower and in the vertical center of the tower, the level at which the oil is liberated from nozzle 13 being approximately one-third of the height of the tower measured from its bottom. It will be observed that at or near the horizontal center of the tower 11 is a baflie or splash plate 14, for the heated oill from nozzle 13 to splash against, which readily liberates all vapors, the space within the tower being otherwise free and clear and normally without pressure, exceeding normal atmospheric pressure. The heated oil flows through the pipe 10 into lthe tower 11 without any pressure other than the low pressure necessary to pump the crude oil to the still, plus the pressure caused by expansion of the oil as it is raised in temperature, which ordinarily is not above thirty pounds pressure on the crude oil discharge line from the pump. rlhe heated oil flowing through the nozzle 13 passes into the unrestricted comparatively large expansion space or" the tow-er 1l, which is un heated otherwise 'han by the heat of the product passing into and through it, and the oil is thereby instantly released ot all pressure, whereupon there is an immediate evaporation of the lighter volatile hydrocarbon constituents el crude oil, the vapor discharging through a vapor line 15 leading from the top of the tower, while the heavier products or unvaporized oil fall back into the bottom of the tower, as indicated at 16 and, in the case of 'tower 11 of unit A, flow by gravity out through a pipe 17 to the hot oil pump 18. A suitable glass or column 19 is provided upon the side ot the tower for indi cating the level o'l the unvaporized body of oil in the tower. Connected with the pipe 15 or otherwise communicating with the tower 11 is an automatic safety and vacuum valve 20, provided to enable any excess pressure to be exhausted or controlled as occasion may require. The vapors separated from the oil in each tower l1 and discharging through the vapor pipe 15 passes into the base of a dephleginator or separating tower 2l coinprising a tank or receptacle having a vapor outlet at its upper end communicating with a vapor discharge pipe 22 leading into the base of a second dephlegmator or separating tower 28. ln each dephlegmator is arranged a series of baos 24 alternately projecting at dii'ierent horizontal levels from opposite sides of the dephleginator tank so as to form a circuitous passage for the uplowing vapors, a final baille 25 in the form of a perforated plate of the saine diameter as the internal diameter of the dephlegmator tank being placed at the top of said tank to act as a bubble tray. 0n top of this tray is placed a layer 26 ot' furnace coke or the like for a catalytic action. ln these dephlegmators, vapors are separated, the heavier products being condensed and falling by gravity to the bottom of the dephlegmators and are thence discharged through line 27 to a cooler 28, thence flowing by gravity to the receiving house 29, as hereinafter described. The vapors discharge iroin the dephlegmator 23 through a pipe 8O communicating at its delivery end with the coil of a condenser comprising an inlet header 31, an outlet header 32 and a series of cooling pipes 88 extending between said headers, said coils being cooled in practice by water constantly flowing through the condenser box or tank 34. The area or" each header 31 and 82 corresponds in practice with the aggregate area of the pipes 88, thus balancing the pressures and allowing easy flow of vapors and liquids and preventing any back pressure at this point in the system. The vapors passing from each expansion tower 11 to the associated dephlegmators 21-23 are thus cooled and condensed in the associated condenser, and the products in the form of gasoline, naphtha, kerosene, stove distillate and gas oil pass outward from said coolers and condensers through pipes 85, 36, 87, 38, 89 and 40, to the receiving house 29 in which they may be inspected and tested for gravity and color, and thence pass to receiving or storage tanks 41, 42, 43 and 44, from which they may be discharged through the lines 45, 46, 47 and 48, by means of pumps 49, 50, 51 and 52 to any other suitable storage tanks or direct to tank cars for shipment.

It will be understood that as the oil from the still 1 of unit A is heated at a very low temperature, the hot vapors may freely rise therefrom in the associated expansion tower 1l before they go into the associated dephlegmators 21-23. The distilling unit A will operate to relieve the crude hydrocarbon of a certain proportion of the more volatile content, and unit B is provided in order that the remaining light content of crude oil may be similarly extracted ata low temperature without any cracking action, and without discoloration or contamination of the prod ucts. To this end, the outlet pipe 17 from the expansion tower of unit A having therein the pump 18 is connected by a pipe 53 with the inlet end of the pipe coil of still of unit B, whereby the portion of the oil treated by the primary still (still of unit A) and discharged through the said outlet 17 of the said expansion tower of unit A will be supplied to the still of the second unit B and treated on its passage through said unit B in the manner previously described for the extraction oi' the kerosene, stove distillate and gas oil. The unvaporized oil or residuum of the second unit B drops to the bottom of expansion tower' 11 and flows by gravity through its discharge pipe 17 to the casing or chamber of exchanger 8 and thence out through a pipe 54 containing a pump 55 for forcing the residuum into a receiving tank 56. lThis residuum is available as fuel oil or for other purposes and may be discharged rom tank 56 and by means of a pump 57 through a pipe 58 to any point for further storage. This product is fuel oil and will meet all specifications as to gravity, flash and fire test. The oil passing through the still of unit B is heated to a higher temperature than the crude oil passing through the still of unit A for an obvious purpose, but this temperature is still comparatively low, far below cracking temperatures and hence the oil and vapors will not be unduly heated and discolored, and similarly the oil vapors in the expansion tower of unit B will flow in a purified state to the dephlegmators and condensers therein for liquefaction and delivery to the receiving house and thence to the receiving tanks. As a result, it will be understood that all the lighter hydrocarbon content of crude oil between the low gravity of gas oil and the high gravity levels of gasoline will be liberated in the two stages of treatment, and a resultant product obtained which is of Beaums gravity suiiiciently high to meet all good specications and the gasoduced either from the shell still or fromv cracking still processes necessary for putting the gasoline, kerosene and stove distillate into condition for commercial use. The fuel gases from the combustion chambers of stills l of units A and B discharge through pipes or iiues 59 and 60 to a stack 6l. In these pipes or iues are suitable controlling dampers 62. I also provide a return pipe or flue 63 for conducting the hotter fuel gases from still l of unit B back to the combustion chamber of still 1 of unit A, thus reducing heat losses to a minimum and ensuring economy in the use of fuel. A damper 64 in the pipe or flue 64 permits said flue to be thrown into or out of operation at will.

It is well known that all crude oil contains more or less water and basic sediment, the percent depending entirely on local conditions and fields. Before this crude oil can be treated in a refinery still, this moisture must be removed either by steaming the crude to precipitate the moisture, which takes time, or by dehydrating, and if the-latter method is used, the temperature necessary in dehydrating is above the initial boiling point of the crude, resulting in a loss of the lighter hydrocarbon content of crude oil, making such method costly. All crude oils also contain a certain percent of carbon and sulphur causing trouble and difhculties in the distilling operation.

In my process, the crude oil does not have to be steamed or dehydrated, as I make use of water as a separating agent. I use from four percent upward of water with the crude oil charged to my apparatus, the crude centrifugated to obtain water content if such content is less than fourk percent and the sulphur content not over .36 of one percent. Where the water content is less than four percent I add free water until the water con to :a non-corrosive sulphur.

tent isfouri percent or higher, and should' the sulphur content be higher than .3610i one -percentluse more water in the crude accord- ;inglyand canuse up to. percent economically .oni highsulphurl content crudes. As-all l I-crudes contain carbon and sulphur in propor- -tionsiapproximately one of carbonto two of sulphur, to` separate them it isnecessaryto .havelsome medium that will hold -them separated. l'For this purpose I admit ywater through a pipe 65 with the crude oil in the vline Vbefore it renters the chargingpump 7.

This water is admitted in bulk, i. e., in a non- V subdividedV state, in which'condition it-tlows 4with'theoilfto the charging pump,`but in passingI .through `the charging pump, the water is agitated withfthe crudeI oil and broken up infsmall globules before entering ywiththeoil in still l. As the oil passes vvthroughthe coil and the temperature yinu-creases, the globules are held in suspension until the oil' reaches lSOOto 212 F. Between lthese temperatures the water does its work of breaking down the hydrogen sulphide in the crudeoil: and liberating the hydrogenfand f separating the carbon andsulphur and chemi` cally changing the latter from a corrosive When the temperature reaches 212' the carbon is freed; of

. all sulphurfand any, other grease or sediment that isk soluble in .boiling water and the corrosive sulphur is changed from a corrosive to a non-corrosive form which is not injurious'in any way. The steam generated from the water travels along with the oilvapors -and keeps the sulphur and carbon separated until they reach the expansion towers, where the sulphur and carbon are liberated from the vapors and drop to the bottom and remain in the fuel oil in non-corrosive form, such as will not injure the metal of burners, and/or other equipment; while the steam remains with the vapors, still washing them, and goes out through the top of the expansion towers 1l and through the dephlegmators and condensers to the receiving house, asv

the oil vapors will condense more readily than steam vapors. Each condenser box is so arranged as to trap oill the steam at the point in the condenser coil where all oil vapors are condensed, and the oil condensate discharged is free of all carbon and sulphur and the gasoline andv kerosene are waterwhite in color, odor sweet, and of doctor test without any further chemical treatment. By thus using water as a separating agent the sulphur and carbon are broken down, no recycling of any of the products is necessary, the still may run charged to capacity with crude at all times, and all reflux in the dephlegmators is drawn oft at the bottom oi parafn base crude oil, the distillate is left* in as good condition for pressing as done by the shell still method.

It will be understood that the flow of the fuel oil residuum through the exchanger tank 9 on its discharge from still l of unit B pro- Vides for the heating of the fresh oil flowing through coil 8, thus heating the fresh oil prior to its introduction to the still l of unit A, and thereby, through heat exchange, cooling the residuum and saving fuel in the preliminary distilling action.

Having thus fully described my invention, I claim:

The method of distilling crude oil, which consists in flowing crude oil through a pipe to a primary still, flowing water from the source of supply to the pipe for admixture with the oil, subjectingthe oil and Water in course of flow to forcing agitation so as to eect a thorough admixture thereof, heating the oil and Water to a temperature of from 300o to 350 F. and generating the steam from the water for eliminating the sulphur from the light volatile products and changing the sulphur from a corrosive to a non-corrosive condition, separating the lighter and heavier products, conducting the unvolatilized oil to a secondary still and reheating the same therein at a temperature of from 350 to 450 F., utilizing the heat of the residuum from the secondary still to heat the crude oil feeding to the primary still, and utilizing the Waste heat from the secondary still for a heating action in the primary still.

In testimony whereof I aflix my signature.

THOMAS J. RYAN.

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