DE2629984A1 - PROCESS AND CIRCULATING FILTER FOR SEPARATING SOLIDS, IN PARTICULAR WAX, FROM OIL - Google Patents

Description

Patent assessor * Hamburg, June 9, 1976

Dr Gerhard Schupfner

Deutsche Texaco AG _{T 76 QQ1 iD}

2000 Hamburg 13 ^{T 7b} ° ⁰¹ ^ ^D

Middle way 180

TEXACO DEVELOPMENT CORPORATION 135 East 42nd Street New York, N.Y. 10017 UNITED STATES.

Method and rotating filter for separating solids, especially wax, from Ul

When separating wax from lubricating oil, for example by means of a circulating suction filter of the Oliver type, Eimco or Goslin-Birmingham tend to have very small wax crystals in addition, together with the first filtrate during the first few seconds in which the filter cloth is still clean immersed in the waxy oil-solvent slurry is to be sucked through the filter cloth. This phenomenon is also referred to as "priming". These wax crystals often cause clouding and sometimes flaky precipitates in the dewaxed oil. However, such a cloudiness is bothersome and has hitherto only been accepted because there are few and hardly any economical methods for removing such haze are known. For well-known circulating Suction filters such as those mentioned above and, for example, the Oliver filter, which is described in the manual "Chemical Engineering Series "by W. L. Badger and W. L. McCabe, McGraw-Hill Book Vo., Inc., New York, 1936, pages 485-490 and is shown, it holds that "A low initial pressure can mean that in the first few cycles the Press no clear filtrate is obtained, but this is more than offset by the higher filtration throughput

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and the consequent higher performance "(page 489, lines 19-22).

The object of the invention is therefore to create a method for the separation of solids from the filtrate, which before the formation of a thick cake of solids on the The outer surface of the filter has passed through a filter which is partially immersed in one of the solid particles circulates in suspension in a trough containing slurry, for the purpose of obtaining a solids-free FiI-trats.

The invention is also intended to provide a method for carrying out this method, namely for separating solids von einäta filtrate, which before the formation of a for solid particles impermeable solid filter cake has passed through a filter on the outer surface of the filter, which is partially immersed in one of the solid particles circulating in suspension in a trough containing slurry, serving a rotating filter with continuous Suction can be created with which a solids-free filtrate can be obtained.

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In addition, the invention is intended to provide a circumferential wax separating filter be created with continuous suction, with the very small wax crystals that before formation of a wax cake impermeable to wax crystals on the filter from the Filtrate that has passed through filters can be separated in order to obtain a clear and wax-free filtrate or oil, as well higher filter throughput rates and longer service life of the filter material while avoiding the precipitation of flakes in the dewaxed oil and had fewer operational problems than with other removal measures on wax crystals to achieve traceable opacities.

The circumferential wax separator filter with continuous suction should be simple in its operation and structure, be economical to manufacture and assemble and a higher degree of efficiency with the complete separation of Wax from a waxy oil-solvent slurry exhibit.

The individual features and advantages of the method of separating solids, the method of assembly a filter and the rotating filter with continuous suction according to the invention are hereinafter explained in more detail using the exemplary embodiments shown in the drawing.

In the drawings is an embodiment as an embodiment an apparatus for carrying out the method according to the invention, with the same Reference numerals are used to designate the same parts in the various illustrations.

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-A-

Fig. 1 is a schematic elevational cross-section through a rotating wax separator filter with continuous suction corresponding to the line 1-1 of FIG. 2.

FIG. 2 is a schematic longitudinal section taken along line 2-2 of FIG. 1.

FIG. 3 is a schematic cross section taken along line 3-3 of FIG. 2.

Fig. 4 is a schematic view of the circulating device for the rotary wax separating filter with continuous suction for the oil-solvent filtrate containing small wax crystals Formation of the wax cake on the filter.

The invention disclosed herein is not in its application to the details of construction and arrangement of the illustrated and described parts for carrying out the disclosed method are limited and can also be used with other devices and in other ways. The same applies to those used here for description purposes only Terminology. Many modifications and further developments should also be apparent to those skilled in the art which, insofar as they fall under the claims, are also to be included in the subject matter of the invention.

The invention relates to a method for separating solids that have passed through a filter, a method for assembling a rotating solids filter with continuous suction and an apparatus to perform these two procedures.

(A) Method of filtering out particulate matter a slurry. With a circumferential, cylindrical

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Solid filter with continuous suction that is used in revolves around a trough containing a slurry with particulate matter suspended therein, the slurry becomes with the solid particles contained in this by means of a negative pressure acting on the inside sucked through the filter surface to a chamber located inside the cylindrical filter. The longer the The filter surface is submerged during its circulation in the slurry in the trough, the thicker it becomes Solid cakes formed on the outer surface of the filter until after a predetermined time for the respective slurry trough no more solid particles pass through the cake and then through the cake and The slurry drawn through the filter is a clear, particulate-free filtrate. However, since before Formation of the increasingly thick solids cake initially along with the slurry pass through the filter, the total filtrate is contaminated with solid particles, which may cause turbidity in the filtrate.

Accordingly, there is the method of separating out the solids, which prior to the formation of the solids cake have passed through the outer surface of the filter together with the filtrate in order to obtain a solids-free and clear filtrate on the output side in that

1) the slurry with those suspended in it Particulate matter is passed through the filter for a predetermined time until sufficient thick solids cake is formed, which further passage of solid particles through the Cake and the filter prevents, and

2) the filtrate with the solid particles suspended therein, which during the predetermined time passed through the filter from the rest

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The filtrate is separated to a solids-free and clear To obtain filtrate.

A further process step can consist in that the filtrate with the solid particles suspended therein is returned to the trough for renewed filtration.

As a further process step it can be provided that the predetermined time during which the slurry with the solid particles suspended therein is passed through the filter for different slurries with solids containing troughs is dimensioned in such a way that only one clear and solids-free Filtrate remains.

B) Method of depositing wax from a slurry. Furthermore, a rotating wax separator filter with continuous suction is disclosed, which in ~ a Trough is rotatably mounted, which contains a waxy oil-solvent slurry on the partially When the filter is rotated, the outer surface of the filter submerged in the trough creates a wax cake of increasing thickness on the outer surface of the filter trains.

The process of depositing small wax crystals, which are together with the filtrate before the wax cake is formed have passed through the outer surface of the filter for the purpose of obtaining a wax-free filtrate, consists in that

1) the waxy oil-solvent slurry with the small wax crystals contained therein passed through the filter for a predetermined time until the wax cake formed has a sufficient thickness through which further penetration of Wax crystals is prevented by the filter cake and the filter and

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2) the small wax crystals that have passed through the filter during the predetermined time containing initial filtrate separated from the remaining filtrate and a wax-free, clear filtrate is obtained.

A further process step can consist in that the filtrate with this contained in this small wax crystals is returned to the trough.

A further process step can also consist in the fact that the predetermined time during which the waxy Oil-solvent slurry through the filter into waxy Oil-solvent slurry containing different Trögen is passed through, is dimensioned so that all small wax crystals in the filter remain behind and a wax-free filtrate remains.

(C) Method of assembling a solid filter. The process of assembling a rotating solids filter with continuous suction for separation of solids from a Filtrataufschläiranung that before Formation of a solid cake on the outer surface of the filter have passed through the filter for the purpose of recovery a solids-free filtrate slurry is that

1) a cylindrical filter drum, which is provided with a filter material on its periphery, rotatable about its longitudinal axis and partially into one containing the slurry with the suspended solid particles Trough is stored submerged,

2) a suction device is connected to the cylindrical filter drum, which serves to remove the slurry containing the suspended particulate matter through the submerged portion of the filter suction and on the outer surface of the filter material with the filter drum partially immersed in the trough

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2623984

To form solid cakes of progressively increasing strength,

3) the permeability of the filter material is dimensioned so that some solid particles together with the slurry containing the solid particles in suspension pass through the filter material can until the filter drum has rotated in the trough for a predetermined time and the thereby formed Solid cake has reached a thickness at which it and the filter material for solid particles have become impermeable and

4) with the cylindrical filter drum

Rotary bearing head is connected, which is used to remove all the filtrate with the solids contained in this only then take up when the filter drum has rotated during the predetermined time and all the rest, through the filter material and the slurry passing through on this formed solid cake are clear and solid has become.

(D) Method of assembling a wax separating filter. The procedure for assembling a rotating wax separator filter with continuous suction to separate small wax crystals from a filtrate, the have passed through the filter prior to the formation of a wax cake on the filter, for the purpose of obtaining a wax-free one Oil-solvent slurry is that

1) a cylindrical filter drum, which is provided with a filter material on its periphery, rotatable around its longitudinal axis and partially into a trough containing the waxy oil-solvent slurry is stored immersed,

2) A suction device is connected to the cylindrical filter drum, which is used to remove the oil-solvent slurry through the eings-i-sushfcen part suction through the filter and on the outer surface of the

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With the filter drum partially immersed in the trough, the filter material progressively increases in a wax cake To develop strength,

3) the permeability of the filter material is dimensioned in such a way that a few small wax crystals come together with the oil-solvent slurry through the Filter material can pass through until the filter drum has rotated in the trough for a predetermined time and the wax cake thus formed has reached a thickness at which it has become impermeable to wax crystals and prevents further passage of wax crystals through the wax cake and the filter material , and

4) with the cylindrical filter drum

Rotary bearing head is connected, which serves to hold all the filtrate with small wax crystals contained in this only take up when the filter drum has rotated during the predetermined time and all the rest, oil-solvent slurry passing through the filter material and the wax cake formed thereon has become clear and free of wax.

A further process step can consist in that the pivot bearing head is connected to the trough and only filtrate with in this contained small wax crystals is returned to the trough.

It can also be provided that

1) an adjustable block serving to set the predetermined time is arranged on the rotary bearing head and

2) the pivot head is made responsive to the adjustable block in such a way that everything oil filtrate with small wax crystals contained in this from the trough with the filtered waxy

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Oil-solvent slurry supplied to the rotary bearing head and from this only wax-free, clear filtrate is discharged.

By means of the proposed method for assembling a filter, others can of course also be used assemble as the filter described below.

An embodiment of a rotating filter with continuous suction is described below. FIG. 1, which is a cross-sectional view taken along line 1-1 of FIG. 2, illustrates details of the FIG Fig. 1 and 2 shown revolving filter with continuous suction 10, which mainly consists of a cylindrical, horizontally arranged filter drum 11 with pivot pin 12 (see FIG. 2, the rear pivot pin is not shown), which is rotatably mounted about its longitudinal axis in a trough 13, the one contains waxy oil-solvent slurry 15. The cylindrical filter drum 11 and the pivot pin 12 of Fig. 2 are rotatable within the trough 13, as shown in Fig. 1 by means of corresponding flanges a hood 14 is attached on opposite sides of the trough.

The filter drum 11 of Fig. 1 has a rigid, cylindrical ümfangswand which is surrounded by a porous filter material 17 at a distance to the outside. By Partition walls 18 are formed around the entire circumference of the filter drum 11, chambers 19. A negative pressure or Vacuum is applied to these chambers 19 by means of leading and trailing pipes 20 and 21, respectively. These As can be seen from FIG. 2, pipelines pass through the front pivot pin 12 to the pivot bearing head 22 led in front.

80988 3/0922

The pivot pin 12 shown in Fig. 2 is rotatable in the pivot bearing head 22 with the interposition of a wear plate 16, the flow through the pipes 20 and 21 between the chambers 19 and the pivot pin 12 is controlled by the rotary bearing head 22 of FIG. Figure 3 is a view of the pivot head 22 and the control chambers on a larger scale.

As can be seen from FIG. 3, the wear plate runs with the inner and outer pipes opening into it 20 or 21 counterclockwise, in sealing engagement with the stationary pivot head 22 is held. The four suction lines 23, 24, 25 and 26 shown in FIGS. 2 and 3 suck in liquid or slurry from the various chambers 19 shown in FIG. 1 on the circumference of the rotating filter drum at. Liquid or air is sucked in »Three fixed blocks 27, 28 and 39 and the single, adjustable one Block 29 basically divide the rotary bearing head 22 into several chambers. The fixed block 39 is located close to and trailing to the stationary block 28, which is used to initiate the filter periods serves.

In operation, the suction line 23 shown in Fig. 3 between the blocks 29 and 27 sucks all the filtrate in the Filter circuit from the corresponding, submerged chambers 19 of the filter shown in Fig. 1, wherein the wax is completely filtered out as it passes through the thick wax cake 30 and the filter material 17. the Suction line 24 of Fig. 3, which is located between blocks 27 and 28, sucks during a cake washing phase Air and a solvent discharged from a filter cake washing nozzle 31 shown in FIG. of those located in this area in Fig. 1,

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speaking filter chambers 19. The suction line 25 of Fig. 3, which is located between the blocks 27 and 28, also sucks during the spraying and washing phase Air and solvent from one shown in FIG Filter cake washing nozzle 32 is dispensed through the corresponding filter chambers located in this area

19 at. The nozzle 33 shown in FIG. 3 emits an inert gas stream during the filter cake drying phase from e.g. flue gas, through which the wax cake 30 shown in FIG and 2 is released, so that a scraper 34 shown in FIG. 1 scrapes off the wax cake 30 and a wax screw conveyor 35 can supply, through which the wax cake is supplied to a (not shown) container. The drying gas, which is produced by the nozzle shown in FIG. 3 and located in the rotary bearing head 22 of FIG 33 is released, passes through the few pipelines located between the block sections 28a and 28b

20 and 21 of FIG. 3 in the opposite direction to the corresponding chambers 19 of FIG. 1 and passes through through the filter. Flue gas or exhaust gases have a low oxygen content.

The novel mechanical part of the revolving wax separating filter disclosed here with continuous suction for carrying out the wax deposition process is as follows: This consists of the one shown in FIG. 3 illustrated adjustable block 29, which is in the pivot bearing head 22 shown in Fig. 2 between the stationary Blocks 39 and 27 inserted and fixed in this. In this area, at the beginning of the The suction process of the waxy oil-solvent slurry through the filter into the filtrate increases Number of crystals on the filter material 17 shown in Fig. 1 and-forms during the circulation of the

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Filter drum with the immersed filter material located on it through the trough with waxy Oil-solvent slurry gradually thickens wax cake 30 from. Depending on the particular waxy oil-solvent slurry being filtered the adjustable block 29 is set so that the filter in this area during a predetermined Time can turn during which the formed wax cake has not yet become thick enough to make another Prevent wax crystals from penetrating the cake and filter material. The thereby obtained The filtrate with small wax crystals located therein is drawn off from the chambers 19a-19d and added to the wax-containing one Oil-solvent slurry 15 in trough 13 of FIG. 1 returned. In practice, this time can be between 3 to 5 seconds, the angle through which the filter rotates during this time, with a filter drum of 9,144 m in diameter can be about 24 degrees. Therefore, an additional suction line is required for this initial filter time 26 required. Since the wax cake on the adjustable block 29 becomes thick enough to hold back all the wax crystals, is that in the adjacent area from the adjustable block 29 of Fig. 3 to the stationary The filtrate collected in block 27 is clear and wax-free and can be discharged as a wax-free filtrate.

Figure 4 is a schematic representation of the discharge and circulation device for the rotating filter with continuous Suction. The waxy filtrate arrives from the suction line 26 as shown the sampler 36 which determines that the filtrate contains wax. If the filtrate does not contain wax, the valve 37 is opened so that the wax-free filtrate with the remaining wax-free filtrate outlet stream is mixed. When the sampler 36 the presence

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_ 14 -

of wax crystals indicates, only the valve 38 is opened and the waxy filtrate into the trough with waxy Oil-solvent slurry returned.

After removing the solvent, a wax-free oil remains. It becomes a clear oil of better quality lower costs, higher filter throughput, longer service life for the filter material, while avoiding the Formation of a flaky precipitate in the dewaxed oil end product and obtained with fewer processing problems than with other measures to remove cloudiness caused by wax crystals.

Obviously, it is possible to separate out solid particles that were collected before a solid cake was formed with the filtrate passed through the outer surface of the filter, and to obtain a solids-free and clear filtrate, as well as for assembling circulating Continuous suction solids filters such as the embodiment shown in Figures 1 and 2 in FIG Use procedures other than those described above, depending on the particular slurry used. By means of the method described above, circulating filters with continuous Assemble suction of a different type than the one described above.

The described method and the described circulating solids filter with continuous suction meet all of the above requirements.

While only one apparatus and two methods have been disclosed, it should be apparent that the disclosed solids filter in arrangement and structure also in other ways within that set by the invention

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Framework can be realized, which is why such modifications and further developments are also listed below the claimed scope of protection should be expected to decrease.

- Patent claims: -

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Claims (1)

T? 6 001 D Patent claims: 1. \ Process for depositing small wax crystals that before recovering a wax-free filtrate through the filter surface of an in a waxy oil-solvent slurry Containing trough rotating wax separating filter with continuous negative pressure, which is partially in the trough Slurry is submerged and forms a filter cake of increasing thickness on its surface, have passed through the filter material, characterized in that a) the waxy oil-solvent slurry (15) with the small wax crystals carried along by this through the filter for a predetermined time is passed until the wax cake has a sufficient thickness through which another The passage of wax crystals through the filter cake (30) and the filter material (17) is prevented will, and b) that which has passed through the filter during the predetermined time and contains small wax crystals The filtrate is separated from the remaining filtrate and a wax-free, clear filtrate is obtained. 2. The method according to claim 1, characterized in that the filtrate contained in this small Wax crystals is returned to the trough (13). 3. The method according to claim 1 or 2, characterized in that the predetermined time during which the waxy oil-solvent slurry is passed through the filter in different troughs containing waxy oil-solvent slurry is dimensioned such that all small wax crystals remain in the filter and the wax-free filtrate remains. 609883/0922 4. The method according to claim 1-3, characterized in that a pivot bearing head (22) is connected to the trough (13) and only filtrate with small wax crystals contained in it is returned to the trough, 5. The method according to claim 1-4, characterized in that one for setting the predetermined time serving adjustable block (29) on the pivot head (22) and the pivot head in the Way is made responsive to the adjustable block that all the filtrate with in this contained small wax crystals from the trough with the filtered waxy oil-solvent slurry fed to the rotary bearing head and from this only wax-free, clear filtrate is discharged. 609883/0922 Circulating wax separating filter for carrying out the method according to claims 1-5, characterized by a) a trough (13) serving to receive a waxy oil-solvent suspension (15), b) a cylindrical filter drum (13) with a filter material (17) arranged on its circumferential surface, which is partially immersed in the trough (13) and rotatably mounted about its longitudinal axis, c) arranged within the filter drum (11) for Aspirating the waxy oil-solvent slurry through the submerged section of the Filter material (17) serving vacuum suction devices (20, 21, 23, 24, 25, 26), which for this purpose serve on the outside of the filter material (17) during circulation of the partially immersed in the trough To form a wax cake (30) of increasing thickness within the trough, d) a filter material (17), the permeability of which is such that a few small wax crystals along with the oil-solvent slurry can pass through this up to the filter drum for a predetermined period of time of the trough has run around and the wax cake (30) has assumed such a thickness that it is suitable for Wax crystals has become impermeable, and e) a separating device (29) assigned to the filter drum, by means of which filtrate is also located in this small wax crystals is only collected after the predetermined time has elapsed, whereby the through the filter material and the wax cake (30) formed on this remainder of the Slurry is clear and wax-free can be dispensed. B09883 / 0922 7. Filter according to claim 6, characterized in that the separating device is designed in such a way that Filtrate containing small wax crystals can be returned to the trough (13) for wax deposition. 6 or 7 8. Filter according to ClaimTV7, characterized in that the Filter drum (11) mounted in a rotary bearing head (22) is, through which all the filtrate with small wax crystals located in it can be discharged, and the rotary bearing head (22) has an adjustable block (29) which is used to set the predetermined time and, depending on the setting of the adjustable block, all of the filtrate slurry with in this located small wax crystals in the relevant trough with filtered waxy oil-solvent slurry absorbs, so that only wax-free filtrate on the delivery side of the rotary bearing head is deliverable. 9. Filter according to Claim6-8, characterized in that the chambers (19a-19d) are responsive to the adjustable block (29) in such a way that all Filtrate with solid particles suspended in this before formation of the solid cake (30) through the filter have passed, can be returned to the trough (13), as well as all filtrate without suspended Solid particles that have passed through the solid cake and the filter to the outside is deliverable. / L 609883/0922