US1530091A - Method and apparatus for cracking and distilling oils - Google Patents

Description

March 17, .1925;

c. F. RICHEY ET 4L" METHOD AND APPARA TUS FOR CRACKING AND DI-STILLING OILS Filed June 16, 1924 2 Sheets-Sheet l I N V EN T 0R. -71 15 1:216 a m F424? Z fizzy/66.

A TTORNEQS" Char/as March 17, 1925.

1,530,091 C. F RICHEY ET AL 7 METHOD AND APPARATUS FOR CRACKING AND-DISTILLING OIL Filed June 16. 1924 2 Sheets-Sheet- 2 INVENTOR. Char/65$ Ext/1e H N By Z'aui yZk/ffee.

A TTORNEY-S Patented Mar. 17, 1925.

UNITED STATES PATENT OFFICE...

CHARLES RICHEY AND PAUL Y. DUFFEE, OF FRANKLIN, PENNSYLVANIA, AS- SIGNORS TO W. J'- DUFFEE, TRUSTEE, F FRANKLIN, PENNSYLVANIA.

METHOD AND APPARATUS FOR CRACKING AND DISTILLING OILS.

Application filed. June 16, 1924. Serial No. 720,225.

To all whom it may concern:

Be it known that we, CHARLES F. RICHEY Y and PAUL Y. DUFFEE, citizens of the United States, and residents of Franklin, county of Venango, State of Pennsylvania, respectlve- 1y, have jointly invented a new and useful Improvement in Methods and Apparatus for Cracking and Distilling Oils, of which the following is a specification, the principle of larly, the improved method consists of, first,

cracking the oil in the liquid phase, and second, the continuous handling of such cracked product to effect the distillation thereof. After the heavy oil has undergone the cracking temperatures, it is kept under sufiicient pressure to maintain it in the liquid phase and the temperature is so maintained for a time, after which it is gradually reduced down to a normal temperature, that is, a temperature below that at which the lighter fractions will vaporize when thus cooled and then the pressure is reduced, at which time the permanent orfixed gases are removed from the product. The cooled cracked product is maintained under normal pressure, that is, sufficient pressure only to flow the product through a series of heat exchangers or stills where it is heated up by means of the oil which is being cooled so as to effect the distillation of the cracked product. In order to control the heat during the distillation, closed steam coils or other suitable heaters are employed in the stills or heat exchangers to give the necessary fine temperature control. In addition to this, these stills or heat exchangers are supplied with open steam pipes so that the distillation is in effect steam distillation to obtain a sweet product directly from the distilling apparatus.

The apparatus for carrying out this method consists essentially of a serial system of pipes or tubes through which the oil is passed in order to raise it to the cracking temperature and to maintain it at this temperature for a time and the outlet end of this serial system of pipes or tubes 1s connected to a series of pipes or temperature reducing coils which are within the heat exchangers and through which the cracked Oll flows while its temperature is being reduced until it passes out of the heat exchangers at a low temperature and this low temperature product under high pressure is next passed through a suitable reducing Valve and into a chamber from which the permanent or fixed gases are removed. From this chamber, the product which is under low pressure and low temperature is passed back into the outer chamber of the heat exchanger or stills where it is reheated mainly from the heat absorbed from the oil being cooled so as to efiect the distillation of the desired fractions. From these heat exchangers, or stills, there are, of course, the necessary connecting pipes communicating with suitable apparatus for handling the lighter fractions as they are taken ofi'. To the accomplishment of the foregoing and related ends, said invention, then, consists of the means and methods hereinafter fully described and particularly pointed out in the claims.

The annexed drawing and the following description set forth in detailv certain structure embodying the invent-ion and method of making the same, such disclosed means constituting, however, but several of various structural forms and methods of making the same, in which the principle of the invention may be used.

In said annexed drawing Fig. 1 is a diagrammatic side elevational layout of the apparatus; and Fig. 2 is a top plan layout view.

The present method of cracking oil consists of subjecting the heavy hydrocarbon liquid such as fuel oil or kerosene distillate to cracking temperatures and under pressure, the temperatures and pressures varymg somewhat with the material hein handled but approximating 600 pounds 0 pressure and from 850 to 950 F. The oil is thus maintained in the liquid phase during the entire cracking operation and after it has been heated sulficiently to crack the product in the serial system of pipes or tubes, it is passed out into and through a long tortuous channel where it is cooled down to a temperature below that at which the lighter fractions vaporize. While undergoing this sufiiciently cooled the oil is then passed through a reducing valve into a gas separation chamber from which the fixed gases are removed, these gases being given up by the oil in its cold state. During this assage of oil throu h the heatingand coo ing tubes the oil is ept moving at a substantially constant rate of flow and the volume or cross sectional area of flow is also maintained substantially constant. It has been found that when the gases are taken oii after the temperature has been lowered, that they are substantially dry and do not carry with them vapors of the lighter fractions, and therefore these gases can be used directly for heating purposes without any further treatment.

The cooled cracked product after the gases have been removed, is next passed into a series of stills or heat exchangers, these preferably being cylinders within which the hot oil tubes are located. In these stills, the cracked product is slowly reheated to distilling temperatures and in order to closely control the temperatures in the stills, they are provided with closed steam pipes through which superheated steam may be passed in order to control the exact temperatures to be obtained, thus producing the gravity and product desired. From these stills there are the usual outlet pipes leading to definitestorage tanks for the various fractions, or to a single tank for the entire distilled product.

In order to obtain a substantially sweet product in one operation, it has been found possible toadd steam directly to the oil unergoing distillation so as to effect agitation of the oil in the stills and also to obtain substantially a steam distillation of the product. In this way the resultant prodnot taken ofi is substantially sweet, although it must undergo treatment so 'as to bring it to the correct water white color.

The apparatus consists of the furnace 1, in which are mounted the pipes or tubes 2,

in which the oil is heated to the cracking temperatures. From the heating tubes 2 the oil passes through a pipe 3 to a high temperature heat exchanger 5 comprising tubes 6 connected by headers 7 at the ends, there being smaller tubes 8 mounted concentrically therein and connected together in the header 7, the other end having a header 9 to receive two tubes.

The oil coming out of the heat exchanger 5 is passed through a pipe 10 and is passed into the cooling pipes in one of the series of stills or converters 12, and passes through the tubesin the converter and through the connecting pipe 13 to the second still 12 and then to the third still 12 by the connect- -in g pipe 14. The number and size of these stills or converters and the length of the cooling coils therein are determined bythe' size and capacity of the entire unit.

or piston actuated type.

23 submerged in a cold water tank 24 where.

it is finally cooled to a temperature low enough to prevent vaporization when the pressure is reduced. The cooling coil 23 is employed when necessary and when the oil leaving the heat exchanger 21 is too high in temperature to-prevent vaporization when the pressure is reduced; The temperature of the oil leaving the water-cooled coil 23 is approximately 100 F.

Connected to the outlet end of the coil 23 is a pipe 26, in which is mounted an automatic pressure reducing valve 30 which may be of any suitable type, either of the spring As the oil and gases are relatively cool, the valve does not collect carbon. From the pipe the oil under substantially normal pressure passes up into a chamber 31, the pressure being merely suificient to overcome the friction losses and back pressure in the remainder of the system. The pressure in the chamber is automatically controlled by afloat valve 32 the flow. Excess pressure acts through the 'float valve 32 to open the valve 33,- allowing the gases to escape faster and reducing the pressure on the liquid. These gases in the chamber are the fixed gases in the cracked oil which separate out as soon as the pressure is reduced, and these gases are removed through the valve 33 and a pipe 34 for use in heating orthe like.

Thechamber 31 is merely a vertical tank having a vertical baflle plate 35 extending from a point near the bottom up well above the liquid level. The inlet pipe 26 extends into the chamber on one side of the baflie plate and nearly to the liquid level line. The outlet pipe 37 for the oil is mounted on the other side. of the baflle plate at the same level as the open end of pipe 26. At

the bottom the chamber has a valve controlled drain pipe 38 connected to an accu- *mulation chamber 39 adapted to receive the free carbon which settles out. This small chamber has a draw-off valve 40.

- The oil passing out ofthe chamber 31 is ters at the point 41. It flows through half of the exchanger in the area of the larger tubes, encircling the smaller tubes carrying the oil being cooled. The oil leaves the exchanger 21 at point 42 and passes through a pipe 43 to the third still or converter 12*.

Each still is a large casing having the hot oil tubes 20 and a vertical baflie plate still 12.- The residue 031 from this still 12 is removed through a pipe 50 to a chamber 51 which has a float valve 52 controlling the outlet valve 53 from which the oil may be taken to any storage receptacle for recharging into the apparatus or removed as waste.

Each still has the closed coils or pipes 20 for the hot oil (being cooled) on each side of the partition wall or baiiie plate and these are so arranged that the flow of the hot oil is opposite to that of the oil being reheated. Each still is also provided with closed pipes for steam so that the temperature in the ,still may be very closely controlled to obtain the exact degree of heat for proper distillation. In addition, each still is provided with open steam coils or pipes 61 to allow steam or gas to be forced into the still so as to agitate and sweeten the product, and thus efiect steam distillation at once.

Each still has an outlet conduit 65 lead ing to a fractionating tower 66 with a return pipe 67 to the still, and these towers are connected by suitable pipes 68 to a condenser 69 provided with outlet pipes 7 0 which lead, as shown, to a chamber 71 having a float valve 72 and an outlet valve 73 controlled by the float valve. From the outlet valve the liquid is removed to a suitable storage tank 7 5.

The heavy hydrocarbon which is to receive treatment is drawn from any convenlent point by a pum 80 which forces it under the desired big pressure through a feed line 81, first to the double heat exchanger 21 where it passes through half of the double coils, and thence through the line 82 to the first heat exchanger 5, through which it passes so as to be preheated before being forced into the furnace tubes 2 through the feed line 83. If it is necessary to drain the entire system an outlet or drain pipe 85 is provided which is connected to the furnace coils by means of a valve 86.

Other modes of a plying the principle of our invention may e-employed instead of the one explained, change being made as regards the means and the steps herein disclosed, provided those stated by any one of the following claims or their equivalents be employed.

We therefore particularly point out and distinctly claim as our invention 1. The method of continuously cracking and distilling oil consisting in passing the oil in a stream of restricted cross section at a constant rate of flow through a heating zone, heating it therein to a cracking temperature and under a pressure sufficient to maintain the oil in liquid phase at the temperature employed, immediately passing such heated oil in heat exchanging relation with fresh oil entering the heating zone, thereafter immediately passing such heated oil through a cool'ng zone to reduce the temperature thereof to normal, maintaining the said constant rate of flow in all of these steps, reducing to normal pressure the cooled cracked oil, and immediately reheating such cooled cracked oil under normal pressure by means of the heated oilbeing cooled in said cooling zone to accomplish distillat on thereof.

2. lhe method of continuously cracking and distilling oil consisting in passing the oil in a stream of restricted cross section at a constant rate of flow through a heating zone, heating it therein to a crack ng temperature and under a pressure suflieient to maintain the oil in liquid phase at the temperature employed, immediately passing such heated oil in heat exchanging relation with fresh oil entering the heatng zone, thereafter immediately passing such heated oil through a series of cooling tubes to reduce the temperature thereof'to normal, maintaining the said constant rate of flow in all of these steps, reducing to normal pressure the cooled cracked oil, and immediately passing such cooled cracked oil under normal pressure through heat exchangers surrounding such cooling tubes to accomplish the distillation thereof in a continuous operation.

3. The method of continuously cracking and distilling oil consisting in passing the oil in a stream of restricted cross section ata constant rate of flow through a heating zone, heating it therein to a cracking temperature and under a pressure suflioient to maintain the oil in liquid phase at the temperature employed, immediately reducing the temperature thereof to a predetermined amount in a definite heat exchan er zone, thereafter immediately passing Su heated oil through a coolingzone to reduce the temperature thereof to normal, maintaining the said constant rate of flow in all of these steps, reducing to normal cooled cracked oil, and immediately reheating such cooled cracked oil under normal pressure the pressure by means of the heated oil being cooled in said cooling zone to accomplish distillation thereof.

4. In apparatus for cracking and distilling oil, the combination of a seriesof heating tubes, a series of closed coolin tubes directly connected to said heating tu es, a plurality of still casings enclosing, said cooling ing tubes for bringing the oil to the cracking temperature, a series of cooling tubes di rectly connected to said heating tubes, a coil connected to said cooling tubes, the Whole comprising a system for cooling the oil to normal temperature, a reduction yalve at the end of said cooling system to reduce the pressure to normal, a series of distilling casings mounted around said cooling tubes and providing a long return path for the cooled oil under low pressure in which the oil may be reheated to effect distillation thereof, said valve being connected to'said series of distilling casings.

6. In apparatus for the continuous cracking and distilling of oil, the combination of a series of heating tubes, a series of cooling tubes directly connected thereto and adapted to rediice the temperature of. the oil to normal,-a reducing valve at the end of said cooling tubes and adapted to reduce the pressure of the cooled oil to normal, a series of stills heated by said cooling tubes and connected to said reduction valve to distill the oil as cooled and under reduced pressure.

7. In apparatus for the continuous crackingand distilling of oil, the combination of a series of heating tubes, a series of cooling tubes directly connected thereto and adapted to reduce the temperature of the oil to normal, a reducing valve at the end of said cooling tubes and adapted to reduce the pressure of the cooled oil to normal, a series of stills heated by said cooling tubes and connected to said reduction valve to distill the oil as cooled and under reduced pressure,

means for supplying oil through said heat ing and cooling system under pressure sufiicient to maintain the liquid phase.

8. In apparatus for the continuous cracking .and distilling of oil, the combination of a series of heating tubes, a series of cooling tubes directly connected thereto and adapted to reduce the temperature of the oil to normal, a reducing valve at the end of said cooling tubes and adapted to reduce the pressure of the cooled oil to normal, a series of stills heated by said cooling tubes and connected to said reduction valve to distill the oil as cooled and under reduced pressure, means for supplying oil through said heating and coolin system under pressure sufficient to maintaln the liquid phase and means for removing and storing the lighter fractions as formed on said stills.

' 9. In apparatus for the continuous cracking and distilling of oil, the combination of a' series of heating tubes, a series of cooling tubes directly connected thereto and adapted to reduce the temperature of the oil to normal, a reducing valve at the end of said cooling tubes and adapted to reduce the pressure of the cooled oil to normal, a series of stills heated by said cooling tubes and connected to said reduction valve to distill the oil as cooled and under reduced pressure,

means for supplying oillthrough said heat-

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