CA1042819A

CA1042819A - Inverted channel separator

Info

Publication number: CA1042819A
Application number: CA221,886A
Authority: CA
Inventors: Kenneth H. Toft
Original assignee: Simon Hartley Ltd
Current assignee: Simon Hartley Ltd
Priority date: 1974-03-26
Filing date: 1975-03-11
Publication date: 1978-11-21
Also published as: DE2512291C2; JPS5523082B2; GB1469833A; ES435837A1; AU7912175A; NO140330C; ZA751513B; JPS50160872A; NL7503195A; NO140330B; IT1034538B; DE2512291A1; NO750986L

Abstract

ABSTRACT

A method and apparatus for separating oil from a mixture of oil and water wherein a stream of the mixture is directed along an upwardly inclined inverted channel to separate the oil from the mixture by contact of the oil with the under-surface of the channel for flow upwardly in the channel, and wherein the oil is collected from the upper longitudinal end of the channel and wherein the remainder of the stream is allowed to fall downwardly out of the channel.

Description

~04Z819 ~ ~
TI~ VENTION relates to the separation ::
and removal of oil from oil and water mixtures. - ~:

It is now quite common for the waters of the sea, harbours, rivers, drainage systems and sewage systems to become contaminated with oil.
Particularly serious is the contamination of the . -sea by the accidental or deliberate discharge of oil from oil tankers which can result from collisions ~:
or tank cleaning operations, for example. :
. ' :: ~
Separators are known wherein a mixture of oil and water is caused to flow upwardly in an ~ -inclined direction over means presenting a large surface area to the flow, whereby the oil is . ~ .
separated from the mixture by contact of the oil with such means. Generally, such known apparatus has the disadvantage that removal Or the separated : - :
oil from the residue entails intimate contact between the two, thus preventing complete separation of the .
oil, on account Or possible entrainment Or the 20. collected oil with the outflowing water. . ` :
. , , . ,~,''' It is an object of the present invention to provide a method and apparatus for the separation : -oil from an oil and water mixture which overcomes the disad~lant e aroresaid _ _ : , .' ~ ... ,.'' '''' . '",'~,' '. '.. ,.
21~-- C~l . - . .

~04'~819 According to the present invention, an apparatus :.
for separating oil from a mixture of oil and water comprises a plurality of upwardly inclined laminar flow control members of inverted channel shape from end to end arranged in side by side relation in each of a plurality of spaced vertical levels, means for introducing a stream of the mixture at the bottom of said assembly for upward flow therethrough for separation of the oil by contact with the under-surfaces of said members, means for discharging the oil, thus constrained, from the upper ends of said members, said members being so constructed and arranged in the apparatus, that the remainder of the mix-ture, after said separation of the oil, flows downwardly out of the members in the upper end region of the assembly thereof but prior to reaching the upper end thereof,while said down-wardly flowing remainder of said stream from channels in upperlevels is prevented from counter-flow contact with the al-ready separated upwardly flowing oil discharged from channels in lower levels.

The lnvention will be further apparent from ~ .
the following description with reference to, and as illus-trated by, the several figures of the accompanying drawings, which show, by way of ex~mple only, one form of apparatùs : :
embodying the invention for performing the method thereof.

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1~4Z819 ~ ~ ~

or the drawing:-Fig. 1 shows a side elevation Or the apparatus with a side wall removed to ~:
reveal the interior thereof;
. ': ':
Fig. 2 shows a cross-section through the -apparatus on the line II-II of Fig. l;

Fig. 3 shows a cross-section through the apparatus on the line III-III Or Fig. l;
. " :" ":
and Fig. 4 shows a detail Or the structure .
. seen in Figs. 2 and 3 but on an enlarged scale. . ~ .... .
. .:'`
Referring now to the drawing, it will be seen that the apparatus is essentially comprised by ...
a tank, the major part Or which is in the form of . ~ .
an upwardly inclined duct 10 Or rectangular cross-section and which opens into a chamber ll.at its . -.
upper end, which chamber rorms the remainder Or the tank. Extending upwardly through the duct 10 is a structure 12 rormed rrOm a plurality of longitud-inally extending mutually spaced parallel inverted :
channel membe 13. 'lhe lower end of the structure _ 4 _ . ~ ~ , . . ' ` , ' " ,''' ,.~ ", ~ ':, ' 214-C~

~ 04Z819 12 is upwardl~ spaced from the bottom Or the duct 10 whilst the upper end of the structure 12 is located within the chamber 11.
.
Each Or the members 13 is of L-shaped section, and the members 13 are arranged in layers one above the other. The members 13 in each layer are mounted on a plurality Or longitudinally spaced transversely extending support bars 14. The individual members 13 are spaced from one another laterally in each layer and there is a space between the adjacent superimposed layers. Conveniently the members 13 are disposed so that their sections lie on a square lattice in the manner clearly shown in Fi~. 4. Strips 13a are provided in alternate layers to complete the structure 12 ar,d these strips also form inverted channels by engagement with the side walls of the duct 10.
.' . , -., The base wall Or the duct 10 extends upwardly into the body Or the chamber 11 to form a baffle 18 which, however, terminates somewhat below the extreme upper end of the structure 12 for reasons which will be apparent hereinafter.
. .
An inlet pipe 15 for an oil and water mixture is provided and communicates with a plurality ~5 Or discharge nozzles 16 each Or which is provided ~ 5 -. .
. .'-''~ .-21~-C41 ~ ~ :

~ 104:819 ¦¦ with a ba~i`le to ensure that liquid enterinF the base Or the duct 10 is stilled before flowing upwardly through the structure 12.

The base of the chamber 11 is provided with an outlet pipe 19 for water in the wall thereof furthest rrom the structure 12.

The apex Or the chamber 11 is open to ~ .. .
atmosphere thus to form a small reservoir 20 in which oil can collect. Oil can leave the reservoir 20 by flow over a weir 21 into a chamber 22 from which it can flow away through a pipe 23.
, :...

In use the oil and water mixture enters the duct 10 and flows upwardly through the plurality Or inverted channels provided by the structure 12.
The geometry Or the apparatus is designed having regard to the intended rate of flow of liquid therethrough to ensure that laminar f-low takes place.
As the mixture flows upwardly globules of oil form, float to engage t,he under-surfaces Or the members 13 and become trapped in the apices Or the inverted channels and thus are separated from the remainder of the stream. The length Or the structure 12 is :
such as to ensure that substantially all the oil . ':' ' . ''''''' - 6 - ~ .

~ : .' "' ' ~

21~-C41 . I . .

104'~819 ¦ contained within the mixture is separated in thè
manner described above by the time the mixture reaches that part of the structure 12 adjacent l the upper end of the baffle 18.

The o:l which is trapped in the apices of the channel members 13 flows upwardly there-along to the extreme upper end Or the structure 12 from whence it floats to collect in the reservoir 20. The remainder Or the stream, essentially oil~
free water, falls downwardly out of each Or the inverted channels after the stream passes the end of the baffle 18.

It will be noted that water falling out of an inverted cnannel in an upper layer can fall ¦ through any layers therebelow without contacting the oil streams which are moving upwardly in those layers.
All the water falling from the structure 12 passes downwardly through the chamber 11 for removal through the outlet 19.
. ,' ' Any sediment, in the mixture which might be deposited from ~he stream passing upwardly through the structure l2 will eventua~ly find its way to the base Or tt~e duct 10 by sliding from the upper surfaces of the channel members 13. Such material . . ' ~ ~ ~
~ 7 -214-~41 - , 104Z~l9 ~ ~ ~
can ~asily be removed from the base of the duct 10 during normal maintenance operations.
..'' It will be understood that the rate at which a mixture of oil and water can be fed through the apparatus will be limited by the requirement rOr non-turbulent or laminar flow. .
It rOllows that the size of the apparatus must be increased for increased rates to throu~hput.
It will be understood that the length of the channel members 13 will not need to be increased but that the number thereof will, thus leading to an increase in the cross-sectional area Or the structure 12. For larger sizes of apparatus pairs of structures 12 may conveniently be arranged in back-to-back relationship.
' . . "',~ ,.

The apparatus of the invention is particularly suitable for use at sea for disposing Or oil slicks from the sea surface. An oil slick :`
. can be pumped aboard ship and passed throu~h apparatus of the invention, the re-claimed oil being stored in a tank on board the sh~p or passed to another ship and the residual water being returned directly to : `
the sea. Since the tank Or the apparatus o~ the invention is almost closed, proper functioning of the apparatus is rot adversely affected by movement ~ ;

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10a~2t3~9 thereof ~s would occur when mounted on board ship.
In particularly rough conditions it might be necessary to charge the apex Or the chamber ~1 with a quantity of oil as a precaution against violent rocking causing water to be displaced over the weir 21 into the oil collection line 23.

It will be appreciated that it is not intended to lirnit the invention to the above example only, many variations, such as might readily occur to one skilled in the art, being possible without departing from the scope thereof, as defined by the appended claims.
.
Thus, ror example, the space beneath the structure 1~ and the nozzles 16 may be pa~ked with baffling means such as Raschig rings or the like.
. ' . :- , , Again, for example, the apparatus might be housed in a tank of generally conical or pyramidal form, a plurality of structures Or inverted channel members being disposed within the tank and having their upper ends converging in the region of the apex Or the tank.

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2~4-C41

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. Apparatus for separating oil from a mixture of oil and water, including an assembly comprised by a plurality of up-wardly inclined laminar flow control members of inverted channel shape from end to end arranged in side by side relation in each of a plurality of spaced vertical levels, means for introducing a stream of the mixture at the bottom of said assembly for up-ward flow therethrough for separation of the oil by contact with the under-surfaces of said members, means for discharging the oil, thus constrained, from the upper ends of said members, said members being so constructed and arranged in the apparatus, that the remainder of the mixture, after said separation of the oil, flows downwardly out of the members in the upper end region of the assembly thereof but prior to reaching the upper end thereof, while said downwardly flowing remainder of said stream from channels in upper levels is prevented from counter-flow contact with the already separated upwardly flowing oil discharged from channels in lower levels.

2. Apparatus according to Claim 1 wherein said channel members in each said level are spaced laterally from one an-other and the channel members in adjacent levels are arranged in respectively staggered relationship.

3. Apparatus according to Claim 2 wherein the channel members in each level are mounted on a plurality of longitudin-ally spaced transversely extending support bars.

4. Apparatus according to Claim 1 wherein each said channel member has an L-shaped cross-section whereby its under-surfaces define a downwardly open apex, the collected oil flowing upwardly along the channel surfaces at said apex to discharge at the upper end of said member.

5. Apparatus according to Claim 4 wherein the cross-sections of the channel-shaped members are arranged to lie on a square lattice.

6. Apparatus according to Claim 1 further comprising a tank in the form of an upwardly inclined duct which opens at its upper end into a chamber, said assembly of channel-shaped members extending through said upwardly inclined duct from a position upwardly spaced from the extreme lower end thereof to terminate at a position within said chamber, there being means for introducing the mixture to be treated to the lower end of said duct.

7. Apparatus according to Claim 6 wherein an oil collecting reservoir is provided at the head of said chamber, and wherein a water outlet is provided at the base of said chamber.

8. Apparatus according to Claim 7 having a weir over which oil can flow for removal from said reservoir.

9. Apparatus according to Claim 6 wherein baffle plate means is provided extending upwardly beneath the assembly of channel-shaped members, said baffle means termin-ating at a position below the extreme upper longitudinal end of said assembly and where a major fraction of the oil has beer separated.

10. Apparatus according to Claim 1, wherein each channel in a lower level passes through and terminates beyond a vertical plane passing through the ends of the channels in the level above.

11. A method for separating oil from a mixture of oil and water comprising the steps of: directing a mixture of oil and water along an upwardly inclined assembly which comprise a plurality of of upwardly inclined laminar flow control members of inverted channel shape from end to end arranged in side by side relation in each of a plurality of spaced vertical levels to separate the oil from the mixture by contact with the under-surfaces of said members and constrain the thus separated oil therebelow, discharging the oil, thus constrained, from the upper ends of said members, withdrawing the remainder of the mixture, after said separation of the oil, downwardly out of the members in the upper end region of the assembly thereof prior to reaching the upper end thereof, while preventing counterflow contact between said downwardly flowing remainder of said stream with the already separated upwardly flowing oil discharged from channels in lower levels.