GB1587503A

GB1587503A - Method of breaking down emulsions and a device for carrying same into effect

Info

Publication number: GB1587503A
Application number: GB1564/78A
Authority: GB
Original assignee: SEVASTOPOL PRIBOR INST
Current assignee: SEVASTOPOL PRIBOR INST
Priority date: 1978-01-14
Filing date: 1978-01-14
Publication date: 1981-04-08

Description

(54) METHOD OF BREAKING DOWN EMULSIONS AND A DEVICE FOR CARRYING SAME INTO EFFECT (71) We, SEVASTOPOLSKY PRIBORO STROITELNY INSTITUT an enterprise organised and existing under the laws of the Union of Soviet Socialist Republics, of 14 Ulitsa Gogolya, Sevastopol, Union of Soviet Socialist Republics do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to methods of breaking down various emulsions and to devices for carrying said methods into effect.

The invention can find most utility when applied for separating oil-polluted ship's ballast and bilge water from liquid petroleum products.

In accordance with the present invention, we provide a method of breaking down emulsions, consisting in that the emulsion is made to bubble through a porous coalescent medium of a pelletized polymeric material which has a specific gravity lower than that of the lighter component of the emulsion being broken down and the voids of which are filled with said lighter component, said porous medium being exposed to the effect of centrifugal force.

The herein-proposed method enables one to attain the degree of breaking down emulsions one or two orders of magnitude higher than in the known devices. Use of pelletized material of specific gravity lower than that of the lighter emulsion component provides for establishing a dense ring of pellets of the coalescent medium, located at the centre of the breakdown zone exposed to the effect of centrifugal forces, said pellets having a minimum size of the voids thereof with respect to the total voids content, a feature that tells very favourably on the emulsion breaking-down efficiency. However, an excessively reduced void content of the filler agent is fraught with a danger of blocking up the voids by mechanical suspended matter of a size larger than the size of the void clear area. On the other hand, any increase in the clear passage area of voids of the pelletized medium is equivalent to a reduction in the active surface of the medium itself and, accordingly, to a lower efficiency of breaking down the emulsion into its components. It is proceeding from the above reasons that the bubbling of emulsions through the voids of the medium full of the lighter emulsion component itself makes it possible to employ a pelletized medium whose voids have a clear passage area large enough to preclude blocking up the medium with mechanical suspended matter.

Besides, the presence of the lighter emulsion component in the voids in the medium simulates and plays the part of an active coalescent surface. Moreover, the emulsion fed into the bowl interior constantly replenishes and revivifies the voids in the pelletized medium with the lighter emulsion component, thereby keeping up automatically their composition in correspondence with that of the lighter component in the emulsion proper.

Also in accordance with the present invention, we provide a device for carrying into effect the method of breaking down emulsions, made essentially as a chamber-type centrifugal separator, comprising a hollow bowl enclosing a perforated sleeve which defines with the peripheral wall of the bowl an annular chamber, said sleeve being arranged lengthwise of the axis of the bowl rotation, an inlet for admitting emulsion to be separated to the interior of the sleeve and thence to the annular chamber, said bowl accommodating a chamber for the heavier emulsion component to collect, said latter chamber communicating with the peripheral zone of the annular chamber and being provided with an outlet, and a chamber for the lighter emulsion component to collect, said chamber being communicated with the annular chamber in the zone spaced inwards from the peripheral zone and being provided with an outlet, and a coalescent filling agent comprising pellets of a polymeric material occupying the annular chamber between the peripheral wall of the bowl and the perforated sleeve.

Feeding the emulsion through the perforated sleeve arranged coaxially within the bowl, averts piston-type movement of the emulsion in the interior thereof and formation of stagnation zones that provoke reduction of the clarifying capacity of the device and thereby pollution of the clarified water with the lighter emulsion component. Meanwhile, the presence of a pelletized filler agent in the bowl interior, of specific gravity lower than that of the lighter emulsion component provides for establishing a dense ring of the pellets themselves situated round the perforated sleeve, the packing closeness of said pellets being defined automatically by the volume flow rate of the emulsion under process and the magnitude of the centrifugal force field. In addition, should the clear passage areas of the filler agent be partially clogged up by mechanical suspended matter, an optimum area of the void passages remains unaffected alongside with the amount of the hydraulic friction of the emulsion passing therethrough, this being due to the fact that the pellets are not mechanically interlinked.

Further more, as the voids themselves of the pelletized filling agent are constantly filled with the lighter emulsion component, this provides for favourable conditions, when breaking down oil-in-water emulsions, for self-washing the pellets from mechanical suspended matter getting stuck to the surface thereof.

Devices of the present invention with capacities of 0.6; 3.0; and 12 ton/hour have been used for clarification of ship's oil-polluted water under ship's trial conditions in various fishing areas of the Northern and Southern Atlantic to give full evidence of operational reliability of the devices and high clarifying capacity at a level of pollution not in excess of 2 to 5 parts per million whatever the concentration of petroleum products at the inlet of the device, sea-water temperature, the type of ship's power plant and grade of fuel used.

The device of the present invention can operate without preheating the oil-in-water emulsion and make use of any type of transfer pumps, including centrifugal pumps. The devices of the character set forth in this invention fully conform, according to their characteristics, to the Recommendations of the Intergovernmental Maritime Consultative Organization (IMCO) and to its resolutions adopted at London in 1973.

The overall dimensions and weight of the devices made according to the present invention enable these to be used on every ship irrespective the type, purpose and displacement thereof. Thus, e.g., a device having a capacity of 1.0 ton/hour weighs 117 keg.

It is expedient that the chamber for collecting the heavier emulsion component be made ring-shaped and be communicated with the annular chamber through an annular slit and that the annular chamber accommodate scrapers bearing on the inner walls thereof and secured to the vanes of a reaction impeller situated in the chamber for collecting the heavier emulsion component with a possibility of freely rotating under the effect of the latter passing through the chamber.

Transfer of the clarified heavier component from the annular chamber to the chamber for its collection, followed by its passing from the bowl periphery through the reaction impeller towards the outlet sleeve, establishes torque high enough to set the impeller in rotation along with the vertical scrapers which remove mechanical deposits from the bowl inner surface.

It is likewise desirable that the chamber for collecting the lighter emulsion component is bounded by a tubular member with the zone adjacent to the outer surface which defines with the perforated sleeve an annular space, the tubular member having therethrough ducts closed by springloaded centrifugal valves.

The above feature excludes accumulation of non-condensable gases within the bowl interior, which interfere with the bubbling process of the emulsion under treatment through the lighter liquid component, thereby disturbing the entire break-down process.

It is expedient to provide in the bowl interior a number of electrodes of different diameters and arranged along the axis of bowl rotation, whereas the outlets from the chambers for the lighter and the heavier emulsion components to collect are preferably provided with solenoid-operated valves controlled automatically by said electrodes depending upon the level of the lighter component inside the bowl.

This feature enables one to preclude the penetration of the lighter component into the piping that handles the clarified heavier emulsion component and provide an automatic operation of the devices under any conditions irrespective of the concentration of one of the components in the emulsion itself.

In what follows the present invention is illustrated in a disclosure of an exemplary embodiment thereof with reference to the accompanying drawing, wherein; Fig. 1 is a longitudinal section view of a device for breaking down emulsions, according to the invention; and Fig. 2 is a section taken along the line Il-Il in Fig. 1.

The device for breaking down emulsions accomplished according to the present invention comprises a chamber-type centrifugal separator having a hollow bowl 1 (Fig. 1) provided with a perforated sleeve 2 arranged lengthwise of the axis of rotation of the bowl 1 and adapted for a uniform admission of the emulsion to and distribution within an outer annular chamber of the bowl 1. The bowl 1 is provided with a chamber 3 for collection of the lighter emulsion component. Said chamber 3 is communicated with the outer annular chamber through holes 4 located in a transverse dividing wall 29 formed by a circumferential flange at the lower end of a tubular member 30 co-axial with and inward of the perforated sleeve 2, the holes 4 being adjacent to the periphery of the outer chamber, wherefrom the heavier emulsion component is discharged from the bowl 1. The chamber 3 is provided with an outlet sleeve 5 for discharge of the lighter emulsion component therefrom.

A chamber 6 for the heavier emulsion component to collect is provided in the bottom portion of the bowl 1 under the chamber 3.

The outer annular chamber of the bowl 1 defined between the peripheral wall of the bowl 1 and the perforated sleeve 2 is filled with a pelletized coalescent medium 7 of a polymeric material whose specific gravity is lower than that of the lighter component of the emulsion being broken down.

The chamber 6 is ring-shaped and communicates with the outer annular chamber of the bowl 1 through an annular slit 8 defined between the outer peripheral wall of the bowl 1 and the chamber 3.

A reaction impeller is mounted inside the chamber 6, said impeller being set in rotation by the flow of the heavier component while it is passing through the chamber 6.

The reaction impeller is formed by vanes 9 (Figs. 1,2) held together by a disk 10 (Fig. 1).

The tips of the vanes 9 of the impeller carry scrapers 11 which rotate along with the reaction impeller and are permanently forced against the inner surface of the peripheral wall of the bowl 1 by virtue of centrifugal force. As the specific gravity of the pellets is lower than that of the heavier emulsion component, during the rotation of the bowl the pellets of the filler are forced towards the axis of rotation by virtue of the centrifugal force, thus providing a gap between the inner surface of the bowl 1 and the scrapers 11. Some of the filler pellets 7 may rotate with the scrapers 11.

The chamber 6 communicates with an outlet sleeve 13 via holes 12.

The chamber 3 for collecting the lighter component is bounded by the tubular member 30 which defines with the sleeve 2 an annular space 31, the tubular member 30 having therethrough ducts 14 closed by centrifugal valves 15 which are loaded by a spring 16.

The outlet sleeve 13 of the chamber 6 communicates with a piping 17 closed by a solenoidoperated valve 18, while the outlet sleeve 5 communicates with a piping 19 closed by a solenoid-operated valve 20.

The chamber 3 accommodates ring electrodes 21, 22, 23 of different diameters and arranged along the axis of rotation of the bowl 1, and electrically connected through a collector 24 to a unit 25 to control the valves 18, 20 in keeping with the level of petroleum products inside the chamber3, said unit being electrically connected to the valves 18, 20.

The unit 25 may be of any heretofore known construction.

The bowl 1 runs in bearings 26 mounted about the upper end of the tubular member 30, which is fast about a hollow shaft forming an upper half-shaft 27, and on the sleeve 13 which serves as a lower half-shaft of the device.

The upper half-shaft 27 serves also for feeding the emulsion to the annular space 31 through holes 28 which extend through both the half-shaft 27 and the tubular member. The collector 24 is mounted about the half-shaft 27 where it projects beyond the tubular member 30.

The method of the present invention of breaking down emulsions is carred into effect as follows.

The emulsion to be broken down is fed by a transfer pump (not shown) through the upper half-shaft 27, the holes 28 and the perforated sleeve 2 in a uniformly spread flow to get into the outer annular zone of the bowl 1 which is filled with the pelletized coalescent matter 7. It is under the effect of the centrifugal force, the coalescence occurring on the surface of the pellets of the filling matter 7 and the bubbling of the emulsion through the voids of the filling matter 7 preliminarily filled with the lighter emulsion component, that the emulsion gets broken down into its components, viz., the lighter and the heavier ones. Then the heavier emulsion component is displaced towards the bowl periphery, wherefrom it passes through the annular slit 8 to the chamber 6, from whence the component flows through the holes 12, the sleeve 13, the piping 17 and the solenoid valve 18 to be discharged from the interior of the bowl 1.

The separated lighter emulsion component, having lower specific gravity, accumulates in the voids of the pelletized filling matter 7 as the bowl 1 rotates, to saturate the filling matter thereby providing automatically the bubbling of the emulsion through its own lighter component. The surplus of the lighter component is fed through the holes 4 to the chamber 3 and, with the solenoid valve 20 open, is discharged from the interior of the bowl 1 through the piping 19 and the sleeve 5 (the direction of the flow of emulsion and the components thereof being shown by the arrows in Fig. 1).

If noncondensable gases, such as air are present in the emulsion these, having a specific gravity lower than those of the heavier and lighter emulsion components, are forced by virtue of the centrifugal forces into the annular zone of the bowl 1 adjacent to the perforated sleeve 2. Under the effect of a difference between the specific gravities of the material of the valves 15 and of the noncondensable gases themselves, there arises a centrifugal force which overcomes the tension of the spring 16, whereby the valves 15 open to discharge the noncondensable gases into the chamber 3, from whence said gases are withdrawn along with the lighter emulsion component.

When the heavier component is passed through the chamber 6, a torque sets up on the vanes 9 of the reaction impeller, whereby the latter is made to rotate at an angular velocity other than that of the bowl 1. While rotating the reaction impeller imparts rotation to the scrapers 11 attached thereto, which scrapers are forced against the inner surface of the bowl 1 by virtue of centrifugal force to slide over that surface, thereby preventing mechanical suspended matter from getting deposited upon the walls of the bowl 1.

To exclude penetration of the lighter component into the piping that handles the heavier component, whatever the concentration of either of the components, it is expedient that use be made of an automatic control of the solenoid valves 18 and 20 depending upon the level ofthe lighter component in the chamber 3.

When handling emulsions wherein the heavier component is a current-conducting liquid and the lighter component is a non-current liquid the automatic control system of the solenoid valves 18 and 20 operates as follows.

When the heavier component alone is fed into the interior of the bowl 1 the chamber 3 is filled with an annular body thereof, extending inwards as far as the periphery of the electrode 21, the central portion of the chamber 3 up to the outside diameter of electrode 21 being filled with the non-current-conducting lighter emulsion component remaining from the preceding operating cycle of the separator. This being the case, the lighter component filling the voids of the pelletized filling matter 7 is at the distance from the axis of the bowl corresponding to the position of the holes 4 in the chamber 3.

It is due to electrical conduction properties of the heavier emulsion component that electric current flows between the electrodes 22 and 23, with the result that a command is delivered by the unit 25 for the valve 18 to open and the valve 20 to close.

Whenever a two-component liquid gets into the outer annular chamber of the bowl 1, the lighter emulsion component, upon supersaturating the pelletized filler 7, is admitted through holes 4 into the chamber 3, and the column of the lighter emulsion component forces the heavier emulsion component into the interior of the ring-shaped chamber 6 of the bowl 1 and overlaps the electrode 21. The electric circuit is therefore open between the electrode 21 and the body of the bowl 1 while remaining closed between the electrodes 22 and 23 and the body of the bowl 1. The valve 18 remains open for discharging the heavier emulsion component and the valve 20 is closed.

In the event that the column of the noncurrent-conducting lighter emulsion component overlaps the electrodes 21 and 22 the electric circuit is open between the electrodes 21 and 22 and the body of the bowl 1 and remains closed between the electrode 23 and the body.

Accordingly, the valve 18 will remain in the open position and the valve 20 will open to remain in this position till the dielectric lighter liquid exposes the electrode 22, i.e. restores the electric circuit between said electrode and the body of the bowl 1.

In the case of a very high content of the lighter non-conducting component in the emulsion, the heavier conducting component is likely to be forced by the lighter one from the central portion of the chamber 3 until all three electrodes 21, 22 and 23 are overlapped by the lighter component which results in the circuit being open between the three electrodes and the body of the bowl 1. In this case the unit 25 will supply a command for closing the valve 18 which will remain closed until the flow of electric current between the electrode 23 and the body of the bowl 1 is restored, this taking place when the non-current-conducting lighter emulsion component is removed from the electrode 23 and replaced by the currentconducting heavier emulsion component. The unit 25 then supplies a command for opening the valve 18.

When handling emulsions, wherein the lighter component is a current-conductive liquid and the heavier component a nonconductive one, the sequence of operation of the solenoid valves 18 and 20 is reversed.

In the specific embodiment of the device for breaking down emulsions as represented in Fig. 1 the electrodes 21,22, 23 are accommodated in the chamber 3. However, these may be housed in the annular space filled with the coalescent matter 7, at a distance from the axis of rotation of the bowl 1 not in excess of the distance from the holes 4 in the chamber 3 to the axis of rotation of the bowl 1.

WHAT WE CLAIM IS: 1. A method of breaking down emulsions, consisting in that the emulsion is made to bubble through a porous coalescent medium of a pelletized polymeric material which has a specific gravity lower than that of the lighter component of the emulsion being broken down and the voids in which are filled with said lighter component, said porous medium being exposed to the effect of centrifugal force.

2. A device for carrying into effect the method as claimed in Claim 1, made essentially as a chamber-type centrifugal separator, comprising a hollow bowl enclosing a perforated sleeve which defines with the peripheral wall of the bowl an annular chamber, said sleeve being arranged lengthwise of the axis of the bowl rotation, an inlet for admitting emulsion to be separated to the interior of the sleeve and thence to the annular chamber, said bowl accommodating a chamber for the heavier emulsion component to collect, said latter chamber communicating with the peripheral zone of the annular chamber and being provided with an outlet, and a chamber for the lighter emulsion component to collect, said chamber being communicated with the annular chamber in the zone spaced inwards from the peripheral zone and being provided with an outlet, and a coalescent filling agent comprising pellets of a polymeric material occupying the annular chamber between the peripheral wall of the bowl and the perforated sleeve.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. forced against the inner surface of the bowl 1 by virtue of centrifugal force to slide over that surface, thereby preventing mechanical suspended matter from getting deposited upon the walls of the bowl 1. To exclude penetration of the lighter component into the piping that handles the heavier component, whatever the concentration of either of the components, it is expedient that use be made of an automatic control of the solenoid valves 18 and 20 depending upon the level ofthe lighter component in the chamber 3. When handling emulsions wherein the heavier component is a current-conducting liquid and the lighter component is a non-current liquid the automatic control system of the solenoid valves 18 and 20 operates as follows. When the heavier component alone is fed into the interior of the bowl 1 the chamber 3 is filled with an annular body thereof, extending inwards as far as the periphery of the electrode 21, the central portion of the chamber 3 up to the outside diameter of electrode 21 being filled with the non-current-conducting lighter emulsion component remaining from the preceding operating cycle of the separator. This being the case, the lighter component filling the voids of the pelletized filling matter 7 is at the distance from the axis of the bowl corresponding to the position of the holes 4 in the chamber 3. It is due to electrical conduction properties of the heavier emulsion component that electric current flows between the electrodes 22 and 23, with the result that a command is delivered by the unit 25 for the valve 18 to open and the valve 20 to close. Whenever a two-component liquid gets into the outer annular chamber of the bowl 1, the lighter emulsion component, upon supersaturating the pelletized filler 7, is admitted through holes 4 into the chamber 3, and the column of the lighter emulsion component forces the heavier emulsion component into the interior of the ring-shaped chamber 6 of the bowl 1 and overlaps the electrode 21. The electric circuit is therefore open between the electrode 21 and the body of the bowl 1 while remaining closed between the electrodes 22 and 23 and the body of the bowl 1. The valve 18 remains open for discharging the heavier emulsion component and the valve 20 is closed. In the event that the column of the noncurrent-conducting lighter emulsion component overlaps the electrodes 21 and 22 the electric circuit is open between the electrodes 21 and 22 and the body of the bowl 1 and remains closed between the electrode 23 and the body. Accordingly, the valve 18 will remain in the open position and the valve 20 will open to remain in this position till the dielectric lighter liquid exposes the electrode 22, i.e. restores the electric circuit between said electrode and the body of the bowl 1. In the case of a very high content of the lighter non-conducting component in the emulsion, the heavier conducting component is likely to be forced by the lighter one from the central portion of the chamber 3 until all three electrodes 21, 22 and 23 are overlapped by the lighter component which results in the circuit being open between the three electrodes and the body of the bowl 1. In this case the unit 25 will supply a command for closing the valve 18 which will remain closed until the flow of electric current between the electrode 23 and the body of the bowl 1 is restored, this taking place when the non-current-conducting lighter emulsion component is removed from the electrode 23 and replaced by the currentconducting heavier emulsion component. The unit 25 then supplies a command for opening the valve 18. When handling emulsions, wherein the lighter component is a current-conductive liquid and the heavier component a nonconductive one, the sequence of operation of the solenoid valves 18 and 20 is reversed. In the specific embodiment of the device for breaking down emulsions as represented in Fig. 1 the electrodes 21,22, 23 are accommodated in the chamber 3. However, these may be housed in the annular space filled with the coalescent matter 7, at a distance from the axis of rotation of the bowl 1 not in excess of the distance from the holes 4 in the chamber 3 to the axis of rotation of the bowl 1. WHAT WE CLAIM IS:

1. A method of breaking down emulsions, consisting in that the emulsion is made to bubble through a porous coalescent medium of a pelletized polymeric material which has a specific gravity lower than that of the lighter component of the emulsion being broken down and the voids in which are filled with said lighter component, said porous medium being exposed to the effect of centrifugal force.

3. A device as claimed in Claim 2, wherein

the chamber for the heavier emulsion component to collect is ring-shaped and is communicated with the annular chamber through an annular slit, whereas the annular chamber accommodates scrapers bearing on the inner walls thereof and secured to the vanes of a reaction impeller situated in the chamber for the heavier emulsion component to collect with a possibility of freely rotating under the effect of the flow of the heavier emulsion component passing through the chamber.

4. A device as claimed in Claim 2 or 3, wherein the chamber for collecting the lighter emulsion component is bounded by a tubular member which defines with the perforated sleeve an annular space, the tubular member having therethrough ducts closed by springloaded centrifugal valves.

5. A device as claimed in any one of Claims 2 to 4, wherein the bowl accommodates a number of electrodes of different diameters and arranged along the axis of bowl rotation, whereas the outlets from the chambers for the lighter and the heavier emulsion components are provided with solenoid-operated valves controlled automatically by said electrodes depending on the level of the lighter emulsion component inside the bowl.

6. A method of breaking down emulsions substantially as described hereinbefore with reference to the accompanying drawings.

7. A device for breaking down emulsions substantially as hereinbefore described with reference to the accompanying drawings.