US2136062A

US2136062A - Apparatus for extracting paraffin from mineral oils

Info

Publication number: US2136062A
Application number: US192705A
Authority: US
Inventors: Suss Heinrich
Original assignee: Rheinmetall Borsig AG
Current assignee: Rheinmetall AG
Priority date: 1937-04-19
Filing date: 1938-02-26
Publication date: 1938-11-08
Anticipated expiration: 1955-11-08

Description

H. sUss 2,136,062

APPARATUS FOR EXTRACTING PARAFFIN FROM MINERAL OILS Nov. 8, 1938.

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7 INVENTOR" HE/NE/CH 5415s ATTORNEYS ab/Jau H. SUSS G 3 Sheets-Sheet 3 an I b A! v H 12 ATTORNEYS Nov. 8, 1938.

APPARATUS FOR EXTRACTING PARAFFIN FROM MINERAL OI LS Filed Feb. 26, 193- Patente d Nov. 8, 1938 APPARATUS FOR EXTRACTING PARAFFIN FROM MINERAL OILS Heinrich Siiss, Berlin-Tegel, Germany, assignor to Rheinmctall-Borsig Aktlengesellschal't Werk UNITED STATES PATENT OFFICE Borsig Berlln-Tegel, Berlin-Tegel, Germany, acorporation of Germany Application February 26, 1938, Serial No. 192,705

In Germany 7 9 Claims.

This invention relates to means for cooling liquids, and refers more particularly to an apparatus for extracting parafiln from mineral oils.

In prior art, the extraction of-paraflin from mineral oils is often carried out by circulating the oil through a horizontally. disposed cooling pipe or chiller, a cooling medium, such as liquid ammonia, flowing along the outer surfaces of this pipe. Paraflin is crystallized by this cooling and deposited upon the inner surfaces of the pipe. Then the parafiln is scraped off the walls 'of the pipe by special scraping devices, which may have theform of spiral bodies, and is carried through the chiller by the oil, which is later sent through-a filter wherein parafiln crystals are separated from the oil.

The disadvantage of this'construction is that it requires the use of expensive and exactly fitting scrapers in the chiller. The manufacture of the chillers is a comparatively difllcult and expensive task, since the inner diameters of ordinary pipes may vary to a great extent; for

' with an excellent coefllcient of heat transmission.

example, a pipe of an average diameter of 150 mm. may have variations in diameter amounting to as much as 3 mm. Therefore, in order to provide a perfect flt for the scraping devices, it is necessary to use bored-out pipes, thus increasing the ,manufacturing costs to a considerable extent. If, in order to avoid such high expense, pipes of the usual type areused, paraflin is permanently deposited upon the walls of the pipes, thereby loweringgreatly the amount of the transmitted heat.

An obj ct of the present invention is to eliminate these drawbacks by providing a device for extracting paraflln which is comparatively inexpensive to manufacture and which operates Other objects of the present invention will be apparent in the course of the following specifl cation.

The objects of the present invention maybe realized by causing the cooling medium to flow downwardly in the form of a thin layer along the inner wall of a rotating vertical coolingcyl inder which is surrounded by oil. It is advantageous to combine several vertical cooling cylinders .into one group which is provided with one scraping device, such as a scraping roller. Paraflln contained in the oil is then deposited upon the outer surface of the cooling cylinder and is easily removed therefrom, so that it cannot form a permanent layer of crystals which would diminish the coefllcient of heat transmission.

It is advisable to provide a continuous circu- April 19, 1937 extracted may be'conducted in countercurrent to the cooling medium flowing along the inner wall of the cylinder, the 011 being introduced at the lower end of the container enclosing the cooling'cylinder and being removed from the upper end of the container.

It may be advantageousto provide an additional container below the container for the oil, this second container being'used for receiving the liquid cooling medium and for replenishing it. The container for the cooling medium is provided with vertical channels, preferably extending through the axis of rotation of the cooling cylinder, for conductingv the cooling medium to the upper end of the cooling cylinder.

The invention will appear more clearly from the following detailed description when taken in connection with the accompanying drawings,

showing by way of example preferred embodiments of the inventive idea.

In the drawings:

Figure 1 is avertical section throughv a cooler constructed in accordance with the principles of the present invention;

Figure 2 is a horizontal section along the line 2-2- of Figure 1;

Figure 3 is a horizontal section along the line 33 of Figure 1; a v

Figures 4 and 5 show in horizontal cross section coolers designed for a greater output;

Figure 6 shows another cooling device in vertical section; Y

Figure 7 is a horizontal section along the line l'! of Figure 6; and

Figure 8 is a horizontal section along the line 8-8 of Figure 6.

The cooling device shown in Figures 1, 2, and 3 of the drawings comprises a cylindrical container [0 which contains. three rotary cooling As shown in Figure 1, the vertical cylindrical brush or scraper l1 extends substantially from the top to the bottom of the container 10.

A portion of the shaft I6 is square in crosssection and carries a pinion l8, which is rotatable along with the shaft. The pinion I8 is i 2| through which the cooling medium is introduced. An annular chamber 22 is provided within the cover l2 and is in communication with the pipe 2|. The chamber 22 is also in communication with an opening 25 of a feed pipe 24, which is suspendedfrom the cover l2 and which extends through the chamber 22. As shown in Figure 1, the pipe 24 projects into one of the cylinders 20 and extends through its gear wheel |9.

Two other pipes, similar to pipe 24, which are not shown in the drawings, extend into the interiors of the other two cylinders 20. Since the devices pertaining to each of the three cylinders 20 are the same in construction and, operation, only one of them will be described in this specification.

Another annular chamber ZB'is situated above the chamber 22 and is used for collecting the vapors of the cooling medium. A second pipe 21 is suspended from the cover |2 adjacent the pipe 23. The pipe 21 also extends through a gear ,wheel l9 and into the interior of a cylinder 20,

and is provided with an opening 28 communicating with the chamber 26. The chamber 26 is also in communication with a pipe 29 carried by the coverl2 and used for the removal of the gaseous cooling medium.

' Another inner chamber 30 is provided within the cover I2 and is enclosed by the walls 3|. A plate or cover 32, which carries the support |4 for the motor l3, constitutes a cover for the chamber 3|! and carries a pipe 33 through which crude oil may be introduced into the chamber 30. The bottom plate 34 of this chamber is provided with several openings 35 through which the oil may flow into the interior of the container l and upon the rotating cylinders 20.

The bottom plate ll of the container I0 is hollow and comprises an annular chamber 49 having inner walls 48. 'A plate 36 constitutes the cover for the chamber 49 and carries a vertical pipe 31 by means of which the cooling medium can be introduced into the chamber 49. A pipe 38 carried by the plate H is used for the removal of the cooling medium.

Conical walls 39 are disposed in the middle of the bottom plate II and form a trough used for the removal of the scraped-off paraffin and the oil carrying the same.

The cooling medium circulating through the cylinders 20 is prevented from mixing with the oil by means of a packing 40 enclosing the pipes 24 and 21 and a packing 4| enclosing the pipe 31. In the device shown in Figure 1, these packings have the form of concentric cylinders which are partly filled with mercury, although, obviously,

stufling boxes or other suitable devices may be used for the same purpose.

Each of the cylinders 20 carries a plate 42 which encloses the pipe 21 and is suspended from the top of the cylinder by the supports 43, so that it rotates along with the cylinder.

The operation of the device is as follows:

Crude oil is introduced through the pipe 33 into the chamber 30 and penetrates through the openings 35 formed in the bottom of that chamber into the interior of the container l0. Theoil drops upon the gear wheels I9 of the three containers 20 and flows along the outer surfaces of these containers,

3 However, the oil may also be conducted to the. outer walls of the scraping roller l1 and applied by this roller to the outer surfaces of the cylinders 2|! in the form of a thin layer.

When the motor I3 is switched on, its rotation will be transmitted through the shaft l and the shaft l6 to the pinion l8 and the gear wheels l9 meshing therewith, so that the cylinders 20 will be rotated along with the scraping roller I1.

Therefore, the oil which is applied to the outer surfaces of the rotating cylinders 20 will flow down these surfaces in the form of helical windings.

The cooling medium, which may be liquid ammonia, brine, or the like, is introduced through the pipe 2| into the chamber 22 situated within the cover l2. Then the cooling medium-flows into the interior of the pipes 24 through their openings 25 and is thus introduced into the cylinders 20; it falls upon the plates 42 and is projected against the inner walls of the cooling cylinders 20 by the centrifugal forces developed in the course of the rotationof the plates 42. The

cooling medium subjected to the centrifugal and gravitational forces flows downwardly along the inner walls of the cylinders 20 and will absorb an amount of heat sufllcient for at least a partial evaporation of the cooling medium, said heat coming from the oil surrounding the cooling cylinders 20.

Due to this cooling of the oil, paraflin is crystallized and deposited upon the outer walls of the cooling cylinders 20 and is immediately scraped off by the scraping roller H, which rotates with a speed diflerent from that of the cylinders 20. The scraped-oil crystallized parafiin particles remain in suspension in the oil and are carried by it, the oil carrying the paraffin particles flowing through the trough 39 to a filtering device, not

,selection of the-speed of rotation of the cooling cylinders 20. The oil can be caused to flow along the outer walls of the cylinders 20, or, as is as- ,sumed' in the construction shown in Figure 1,

the container I0 may be filled with oil. In the latter case, the rotation of the cooling cylinders furthers the exchange of heat, due to a difference in speed between the rotating walls of thecylinders 20, the oil movable therewith and the remaining oil, which fills the container l0.

' The constructions shown in Figures 4 and 5 of the drawings are used for plants of comparatively large dimensions. Figure 4 shows a central cylinder 50 which is surrounded by three scraping rollers 5| and five outer rotary cylinders 52, which are all enclosed in a container 53. i

' In the construction shown in Figure 5, there is an inner'ring of six rotary cylinders 80 which is enclosed by six scraping rollers 6| surrounded by twelve outer cylinders 62, the entire aggregate being situated within a'container 63.

In each of these devices, the rotary cylinders are arranged in groups of three, each group being in contact with one scraping roller, all of the cylinders being driven from the middle of the container. By these means it is possible to pro.- vide large cooling surfaces within a comparatively small area.

The device shown in Figures 6 to 8 of the drawings comprises a cylindrical container 18 which encloses three rotary cylinders H. The outer surfaces of these three cylinders are engaged by a scraping roller or brush 12 which is situated in the middle of the container 18 and which is rotatable along with its shaft 13 driven by a motor 14 which is preferably situated above the container 18. The cover 15 of the container 18 carries the support 16 for the motor 14. A

pinion 11 is firmly mounted upon shaft 13 and meshes 'withthree gear wheels 18, each of which is firmly connected with a separate rotary cylinder H. The container 18 carries a bottom plate 19 which is firmly connected therewith and which supports the rotary cooling cylinders H.

A second container 88 is situatedbelow the container 18 and is provided with an inner horizontal plate 8'I which divides the interior of the container 88 into two

chambers

82 and 83. A pipe 84, which is carried by the container 88 and which is incommunication with the chamber 82. is used for introducing the liquid cooling medium into the container 88 and may be closed by a valve 85 operated by a float 88.-

Another pipe 81 which is used for the removal of the gaseous cooling medium is carried by the container 88 and is situated close to the cover 88 of the container;

A long vertical pipe 89 is supported by the partition plate 8|; the lower end of this pipe is in communication with the chamber 83 formed in the container 88. The pipe 89 extends through one of the cylinders 1| and its upper end is situated close to the gear wheel 18 carried by that cylinder. The pipe 89 passes through an opening formed in the cover 88, said opening being closed in an airtight manner by means of the stuffing box 98, and through an opening which is formed in the bottom plate 19 and which is closed by the stufllng box 9|. A plate or disc I M is situated at the upper end of the cooling cylinder 1| and is rotatable therewith. The upper end of the pipe 89 extends through the disc IN and terminates just above that disc.

Similar pipes 89 are situated within the other two cylinders 1I. Since the construction is the same for all the three cylinders, only one of them will be hereinafter referred to in the specification.

Pipes 92 are situated between the

containers

18 and 88 and enclose the long pipes 88. The lower ends of the pipes 89 are in communication with the chamber 83 of the container 88 (Fig. 6). The pipes 92 are also in communication with the cylinders H and are rotatable therewith.

The two

chambers

82 and 83 of the container I 88 are in communication with each other by means of a pipe 93 which extends through the chamber 83 and which connects the chamber 82 with a bent pipe 94 carrying a valve 95. The

other end of the pipe 94 is connected to .a cen- I terior of the container 18 through the pipe 99 and gradually fills the container.

The cooling medium, for instance ammonia, is introduced into the chamber 82 of the container 88 through the pipe 84 having a valve 85, which regulates the amount of the cooling medium .in circulation. The evaporated cooling medium leaves the chamber 82 through the pipe '81, is liquified by a compressor, not shown in the drawings, and is then returned to the chamber 82 through the pipe 84.

When the pump 96 is switched on, it will pump the liquid ammonia contained in the chamber 82 through the

pipes

93, 94 and 91 into the lower chamber 83 of thecontainer 88 and into the pipes 89, causing it to rise within these pipes until it reaches the upper ends thereof. Liquid ammonia flowing out of the upper ends of the pipes 89 will drop upon the plates I8I which are rotatable along with the containers 1|. Due to the centrifugal forces, ammonia will be directed toward the inner walls of the containers 1I and will flow by gravity through the openings formed upon the periphery of the discs IM and down the inner surfaces of the containers H in countercurrent to the flow of the crude oil which rises within the container 18 and flows upward along the outer walls of the cylinders H. A part of the. ammonia will be evaporated and parafiin will be deposited upon the outer walls 01' the rotary cylinders 1I. Ammonia remaining in the liquid state will fiow down the pipes 92 into the chamber 82 of the container 88. 1

crystallized parafiin is removed from the side walls of the cylinders H by the scraping roller 12 and remains in suspension in the oil, which is removed from the container 18 through the upper branch pipe I88 and is poured into a filtering device.

the first stage consisting of a preliminary cooling by a filtrate having a comparatively low temperature. In the second or next stage an evaporating cooling medium, for instance ammonia, may be used.

Whenever a low temperature filtrate is used for a preliminary cooling of the crude oil, the pump 98 is switched ofi and the container 88 is used as a heat exchanger. The low temperature filtrate is then caused to flow downwardly along the inner walls of the cooling cylinders instead of the evapcrating cooling medium, while the oil may be caused to circulate in the same manner as in the other stages, namely, by being introduced intothe container 18 through the pipe 99 and by being removedthrough the pipe I88.

The described devices are considerably cheaper in the manufacture and installation than prior art devices having the same output.

Furthermore, devices constructed in accordance with the present invention may be advantageously employed for carrying out other processes involving an exchange of heat. They are particularly advantageous for certain methods requiring a very rapid heat exchange and the greatest possible transmission of heat. The surfaces used for the exchange of heat are considerably smaller than the surfaces of prior art constructions and the time required for the treatment is considerably shorter, so that a greater output may be attained.

tions is that the continual cleaning of the sur- 1 I faces of the cooling cylinders is automatic and thorough. Furthermore, the driving means for the scraping rollers and the cooling cylinders are situated within a container through which oil flows continuously, so that thorough lubrication is assured.

It is apparent that the specific illustrations shown above have been given by way of illustration and not by way of limitation, and that the structures above described are subject to wide variations and modifications without departing from the scope of the invention. For example, the described constructions can be used not only for the extraction of parafiin from mineral oils, but also for the cooling of other liquids which cause the deposit of crust-like layers upon a cooling surface. It is immaterial for the purposes of the present invention whether the scraping rollers and the cooling cylinders are interconnected by separate drives or are merely in frictional engagement with each other, or whether the cooling cylinders are used for driving the scraping rollers or vice versa. All of such and other variations and modifications are to be included within the scope of the present invention.

What is claimed is:

1. A device for. cooling liquids, comprising a plurality of vertical cooling cylinders constituting a single'group, each of said cylinders having inner and outer heat-transmitting surfaces, 2. single scraping device in, contact with the outer surfaces of all of said cylinders, means rotating said cylinders and said scraping device at different speeds to cause said outer surfaces to move relatively to said scraping device while in contact therewith, means causing the flow of a cooling medium along and in contact with said inner surfaces, and means causing the liquid to be cooled to contact said outer surfaces.

2. A device for cooling liquids, comprising at' least one cooling cylinder having inner and outer heat-transmitting surfaces, means causing the flow of a' cooling medium along and in contact with said inner surface, scraping means in contact with said outer surface, means connected with said cooling cylinder for moving its outer surface relatively to said scraping means while it is in contact therewith, and a container adapted to contain the liquid to be cooled and enclosing said cooling cylinder, the second-mentioned means and the third-mentioned means, whereby the liquid in said container is in contact with said outer surface.

3. A device forv cooling liquids, comprising at least one cooling cylinder having inner and outer heat-transmitting surfaces, means constituting a channel having an end portion projecting into the interior of said cylinder for the introduction of a liquid cooling medium thereinto, means connected with said cylinder for rotating the same, a plate situated within said cylinder below said end portion and connected with said cylinder, said plate having peripheral openings formed therein and being rotatable along with said cylinder, whereby the liquid cooling medium is caused to flow along and in contact with the inner surfaces of the cylinder, and means causing I the liquid to be cooled to contact the outer surfaces of said cylinder.

4. A device for cooling liquids, comprising at least one cooling cylinder having inner and outer heat-transmitting surfaces, a pipe constituting a channel for the introduction of a liquid cooling "medium into saidcylinder, said pipe projecting into the interior of said cylinder, means connected with said cylinder for rotating the same, a plate situated within said cylinder and rotatable therewith, said plate being connected with said cylinder and having peripheral openings formed therein to cause a flow of the liquid cooling medium along and in contact with the inner surfaces of the cylinder, another pipe constituting a channel for the removal of a gaseous cooling medium from said cylinder, the second-mentioned pipe projecting into the interior .of said cylinder, and having an end portion situated below said plate, and means causing the liquid to be cooled to contact the outer surfaces of said cylinder.

5. A device for cooling liquids, comprising at least one cooling cylinder having inner and outer heat-transmitting surfaces, means introducing a liquid cooling medium into said cooling cylinder at one of the ends thereof and causing it to flow along and in contact with said inner surfaces, means causing the liquid to be cooled to contact the outer surfaces of said cylinder, a pipe situated at the opposite end of said cylinder or removing the liquid cooling medium, a mercuryfllle'd sealing container between said pipe and said cylinder, and means constituting a chamber for the liquid cooling medium and in communication with said pipe.

j 6. A device for cooling liquids, comprising at least one cooling cylinder having inner and outer heat-transmitting surfaces, a container adapted to contain the liquid to be cooled and enclosing said cooling cylinder, whereby the liquid in said container is in contact with said outer surface, another container for the cooling medium, the second-mentioned container being situated below the first-mentioned container, means connected with the second-mentioned container and projecting into the interior of said cooling cylinder for introducing said cooling medium into said container at one of the ends thereof, and means connected with the second-mentioned container and the opposite end of said cooling cylinder for the return flow of said cooling medium from said cooling cylinder into the second-mentioned con-' tainer. v

7. A device for cooling liquids, comprising a plurality of vertical cooling cylinders, each of said cylinders having inner and outer heat-transmitting surfaces, a container adapted to contain the liquid to be cooled and enclosing said cooling cylinders, whereby the liquid in said container is in contact with the outer surfaces of said cylinders, another container for the cooling medium, the second-mentioned container being situated below the first-mentionedcontainer, pipes com-.

municating with the second-mentioned container and projecting into the interior of said cooling cylinders,;said pipes having ends situated adjacent the upper ends of-said cylinders, whereby said cooling medium is introduced into said cylinders at the upper ends thereof and is caused to flow downwardly through said cylinders, and pipes connected with the upper portion of the second-mentioned container and the lower ends of said cylinder for the return flow of said cooling medium from said cooling cylinders into the second-mentioned container.

8. A device for cooling liquids, comprising at 1 least one cooling cylinder having inner and outer heat-transmitting surfaces, a container adapted to contain the liquid to be cooled and enclosing said cooling cylinder, whereby the liquid in said container is in contact with said outer surface. another container for the cooling medium, the second-mentioned container being situated below the first-mentioned container, means connected with the second-mentioned container and projecting into the interior of said cooling cylinder for introducing said cooling medium into said container at one of the ends thereof, and means connected with the second-mentioned container and the opposite end of said cooling cylinder for the return flow of said cooling medium from said cooling cylinder into the second-mentioned container, a branchpipe carried by the second-*mentioned container and constituting a passage for the introduction of the liquid cooling medium into the second-mentioned container, a valve situated within the second-mentioned container for closing and opening said passage, and a float situated within the second-mentioned container and connected with said valve for operating the same 9. A device for cooling liquids, comprising at least one cooling cylinder having inner and outer heat-transmitting surfaces, a container adapted to contain the liquid to be cooled and enclosing said cooling cylinder, whereby the liquid in said container is in contact with said outer surface,

\ another. container for the cooling medium, the

container at one of the ends thereof, means connected with said lower chamber and the opposite end of said cooling cylinder for the return flow of said cooling medium from said cooling cylinder into said lower chamber, and pumping means connecting said upper chamber with said lower chamber.

HEINRICH siiss.