GB2591556A

GB2591556A - A separator

Info

Publication number: GB2591556A
Application number: GB2017622.8A
Authority: GB
Inventors: Michael Hoyle Christian
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-11-13
Filing date: 2020-11-09
Publication date: 2021-08-04
Anticipated expiration: 2040-11-09
Also published as: GB202017622D0; IE20190190A2; GB2591556B

Abstract

A separator arrangement comprising a tank 3 for receiving a water-oil mixture and a separator device 15, such as a coalescer, located inside the tank for separating water and oil from the mixture. The separator comprises an outlet for discharging the separated water and one or more oil drain apertures 21 in the sidewall 11 of the tank. A mechanism may adjust the level of the oil drain apertures in relation to the base 9 of the tank; this may comprise a movably mounted plate 39 comprising the oil drain aperture 21, overlapping with an auxiliary aperture 47 in the tank sidewall. The tank may have several consecutively arranged partitions 25 defining oil retention chambers 27, where the oil draining apertures 21 are provided in each chamber. The tank may comprise a levelling arrangement for adjusting the tilt of the tank base, such as adjustable legs.

Description

I

A SEPARATOR

Field of the Invention

The present invention relates to a separator for a dewatering system, more specifically, but not limited thereto, a dewatering system for a bund.

Background to the Invention

Bunding around oil tanks not only captures oil but also rainwater. Any water contained within the bund reduces the bund's storage capacity and could reduce the capacity below legal requirements. Dewatering systems to remove water from bunding are known. These systems discriminate between water and oil and remove only water leaving the oil behind so as not to contaminate environment. A typical dewatering system includes a sump which collects water, a pump and a sensor located in the sump and a control panel mounted on a frame usually adjacent to the sump. The sensor returns signals related to the oil/water contents of the sump to the control panel, which in turn controls the operation of the pump discharging water from the sump. This system maintains the volumetric integrity of the bund by discharging rainwater and leaving the separated oil behind. However, the discharge from any type of sump pump using this technology cannot guarantee that no oil is present in the water being discharged. Regulations exist prescribing maximum amount of oil concentration (e.g. <5mg/1) in the water being discharged directly into surface water. Oil discriminating sump pumps alone cannot meet these legal requirements and must be discharged into a certified full retention oil separator.

An oil separator accepts the discharge (water containing some oil) from a standard bund dewatering system. One type of oil separator is an underground type full retention separator. These separators require a large area for installation and are not always suitable for small live substations where underground high voltage cables occupy most of the ground. This type of separator is also not ideal if the area where it is installed in is within a flood plain. When the area gets flooded, all the oil stored in the separator floats out of the top the separator. Another existing oil separator has been designed to be installed within the bund for the above reasons and also to prevent ground contamination in the event of tank rupture/damage. This oil separator includes an arrangement for separating oil from the water, draining the water and returning the oil back into the bund. The amount of oil in the water discharged from the separator is less than maximum permitted amount and thus legal requirements are met. The final discharge from the separator is usually pumped over the standard height bund wall to surface water run-off. Typically, the separator includes a tank and a filter at the bottom of the tank which traps oil and lets water pass through. The water that passes through the filter is discharged, whereas the trapped oil rises to the surface of the water in the tank and floats on top of the water. Typically, the capacity of the separator tank is about 301. When the separator is in operation, the level of water with a layer of oil on top of it rises due to the difference in the capacities of the sump pump, which inputs the water discharged from the sump into the separator, and the filter. Once the level of water in the separator tank reaches a level close to the maximum capacity, an alarm sounds to alert an operator to remove the oil floating on top of the water manually. This arrangement is unreliable and prone to human error.

In view of the above, it is an object of the present invention to alleviate and mitigate the above disadvantages.

Summary of the Invention

The present invention provides a separator arrangement comprising a tank for receiving a water-oil mixture, the tank having a base and a side wall surrounding the base; a separator device inside the tank for separating water and oil from the water-oil mixture received in tank; and an outlet in the tank for discharging water separated from oil; wherein one or more oil drain apertures are provided in the side wall of the tank at a pre-determined level above the base of the tank.

Preferably, a respective adjusting mechanism is provided for adjusting the level of each of the one or more of the oil drain apertures in relation to the base of the tank.

Preferably, a plurality of said oil drain apertures are provided.

The separator device preferably comprises a filter. The filter may be, for example, but limited thereto a coalescing filter.

The tank may include a number of consecutively arranged partitions which define oil retention chambers through which the water-oil mixture entering the tank passes in order to reach the separator device. Further one or more partitions may be provided above the separator device to define one or more chambers above the separator device. Said one or more oil draining apertures may be provided in each chamber.

The chambers are provided for facilitating oil separation by retaining oil on top of the water in the tank in the chambers as the water-oil mixture travels through the tank. When the water-oil mixture enters the tank, the oil fraction, being lighter than water, rises to the surface. Thus, even before the water-oil mixture reaches the separator device, some oil rises to the top and is retained in the chambers preceding the separator device. This assists the functioning of the separator device by reducing the amount of oil it has to filter. The chambers provided above the separator device serve a similar purpose by reducing the amount oil to be filtered for those parts of the separator device located closer to the outlet of the tank. The overall effect of providing the chambers is minimising oil content in the water discharged from the tank.

The separator device is preferably provided at or near the base of the tank.

A pump may be provided for pumping the water-oil mixture into the tank.

In one arrangement, the level adjusting mechanism may comprise a movable member, such as, for example, a plate, movably mounted on the side wall of the tank (and as such forming part of the side wall of the tank), e.g. via adjustable fasteners, with said oil drain aperture being formed in the movable member; and an auxiliary aperture formed in the side wall of the tank and overlapping with the oil drain aperture so that by moving the movable member with respect to the side wall of the tank the position of the overlap between the oil drain aperture and the auxiliary aperture with respect to the base of the tank can be altered thereby altering the level of the resulting oil drain aperture with respect to the base of the tank.

In another variation, the level adjusting mechanism may comprise a movable shield, movably mounted on the side wall of the tank, e.g. via adjustable fasteners, to move with respect to the oil drain aperture so as to reduce or enlarge the oil drain aperture and thereby alter the level of the drain aperture in relation to the base of the tank.

In one arrangement, the tank may comprise a levelling arrangement for adjusting the tilt of the base of the tank in relation to the surface on which the separator arrangement is placed. For example, but not limited thereto, the levelling arrangement may comprise adjustable legs.

The tank preferably has a lid to prevent foreign matter from contaminating the interior of the tank.

During the operation of the separator arrangement of the invention, the separator device traps oil and lets water pass through. The water that passes through the filter is discharged from the tank. Some of the water from the water oil mixture gets partially filtered and rises above the separator device. The trapped oil rises to the surface of the water in the tank above the separator device and floats on top of the water. Due to the provision of the one or more oil drain aperture, once the level of water, with oil on top, in the tank reaches the one more oil drain apertures, the oil on top of the water automatically exits the tank through the one or more oil drain apertures. Thus, the invention dispenses with the need to use a pump or other device or manual labour to remove the oil from the water surface. The invention is advantageous in that no power consumption is involved and the arrangement is virtually maintenance free, apart from the initial level adjustment operation. Typically, the separator tank is placed inside an existing bund. Therefore, the oil exiting the tank through the one or more oil drain apertures returns to the bund, a place where it is normally stored. The provision of the level adjusting mechanism allows the level of the oil drain apertures to be adjusted to compensate for level irregularities, for example, when the surface of which the tank is placed is tilted or uneven and, if required, to alter the pre-determined level above the base of the tank at which oil is required to exit the tank.

It will be appreciated that although the present invention is described in connection with bund dewatering, the invention is suitable for processing any type of water mixed with oil residues.

It will be understood that, unless otherwise stated, plural and singular terms are used interchangeably.

Detailed Description of the Invention

The invention will now be described with reference to the accompanying drawings, which show, by way of example only, an embodiment of the invention In the drawings: Figure 1 is a schematic cross-sectional elevation of a separator in accordance with the invention.

Referring to Figure 1, a separator arrangement of the invention is indicated generally by reference numeral 1. The separator arrangement 1 comprises a tank 3 for receiving a water-oil mixture 5 through an inlet port 7. A pump (not shown) may be provided for pumping the water-oil mixture 5 into the tank 3. The tank 3 has base 9 and a side wall 11 surrounding the base 9. A separator device 15 is provided inside the tank 3 for separating water and oil from the water-oil mixture 5. An outlet port 17 is provided in the tank 3 for discharging water 19 separated from oil. A number of oil drain apertures 21 are provided in the side wall 11 of the tank 3 at a predetermined level 23 above the base 9 of the tank 3. In the presently described embodiments, the separator device 15 comprises a coalescing filter provided at or near the base of the tank 3, but the invention is not limited thereto.

In the presently described embodiments, the tank 3 includes a number of consecutively arranged partitions 25 which define oil retention chambers 27 through which the water-oil mixture 5 entering the tank passes, as indicated by arrows 29 in order to reach the separator device 15. Further partitions 25 are provided above the separator device 15 to define further chambers 27 above the separator device 15. At least one draining aperture 21 is provided in each chamber 27. The chambers 27 are provided for facilitating oil separation by retaining oil on top of the water in the chambers 27 as the water-oil mixture 5 travels through the tank 3. When the water-oil mixture enters 5 the tank 3, the oil fraction, being lighter than water, rises to the surface. Thus, even before the water-oil mixture 5 reaches the separator device 15, some oil 31 rises to the top and is retained in the chambers 27 preceding the separator device 15. This assists the functioning of the separator device 15 by reducing the amount of oil it has to filter. The chambers 27 provided above the separator device 15 serve a similar purpose by reducing the amount oil to be filtered for those parts of the separator device 15 located closer to the outlet 17 of the tank 3. During the operation of the separator arrangement 1, the separator device 15 traps oil and lets water pass through. The water 19 that passes through the separator device 15 is discharged from the tank 3. Some of the water from the water oil mixture gets partially filtered and rises above the separator device 15. The trapped oil 33 rises to the surface of the water 35 above the separator device 15 in the chambers 27 and floats on top of the water 35. The overall effect of providing the chambers 27 is minimising oil content in the water 19 discharged from the tank 3.

Due to the provision of the oil drain apertures 21, once the level of water, with oil 31, 33 on top, in the tank 3 reaches the one more oil drain apertures 21 at the predetermined level 23, the oil 31, 33 on top of the water automatically exits the tank 3 through the oil drain apertures 21. Thus, there is no need to use a pump or other device or manual labour to remove the oil from the water surface. Typically, the separator tank 3 is placed inside an existing bund (not shown). Therefore, the oil 31, 33 exiting the tank 3 through the oil drain apertures 21 returns to the bund, a place where it is normally contained.

An adjusting mechanism 37 is provided for adjusting the level of each oil drain aperture 21 in relation to the base 9 of the tank 3. The provision of the level adjusting mechanism 37 allows the level 23 of the oil drain apertures 21 to be adjusted to compensate for level irregularities, for example, when the surface of which the tank 3 is placed is tilted or uneven. If required, the level adjusting mechanism 3 can be used to alter the pre-determined level 23 above the base 9 of the tank 3 at which oil 31, 33 is required to exit the tank 3.

In the arrangement shown in Figure 1, the level adjusting mechanism 37 comprises a movable plate 39 movably mounted on the side wall 11 of the tank 3 (and as such forming part of the side wall 11 of the tank 3) via adjustable fasteners 43 engaged in slots 45 with the oil drain aperture 21 being formed in the movable plate 39. An auxiliary aperture 47 shaped as a slot is formed in the side wall 11 of the tank 3 and overlaps with the oil drain aperture 21 so that by moving the movable plate 39 in slots 45 the position of the overlap between the oil drain aperture 31 and the auxiliary aperture 27 with respect to the base 9 of the tank 3, thereby altering the level of the oil drain aperture 21 with respect to the base 9 of the tank 3.

In another variation not shown in the drawings, the level adjusting mechanism 37 may comprise a movable shield movably mounted on the side wall 11 of the tank 3, e.g. via adjustable fasteners similar to those shown in Figure 1, to move with respect to the oil drain aperture 21 so as to reduce or enlarge the oil drain aperture 21 and thereby alter the level of the oil drain aperture 21 in relation to the base 9 of the tank 3.

The invention is not limited to the level adjusting mechanisms described above. A number of ways to adjust the level of the oil drain apertures would be apparent to a skilled person.

Although not shown in the drawings, the tank 3 may comprise a levelling arrangement for adjusting the tilt of the base 9 of the tank 3 in relation to the surface on which the separator arrangement 1 is placed. For example, but not limited thereto, the levelling arrangement may comprise adjustable legs.

The tank 3 preferably has a lid 41 to prevent foreign matter from contaminating the interior of the tank 3.

It will be appreciated that although the present invention is described in connection with bund dewatering, the separator arrangement of the invention is suitable for processing any type of water mixed with oil residues.

It will be appreciated by those skilled in the art that variations and modifications can be made without departing from the scope of the invention as defined in the appended claims.

Claims

CLAIMS: 1 A separator arrangement comprising a tank for receiving a water-oil mixture, the tank having a base and a side wall surrounding the base; a separator device inside the tank for separating water and oil from the water-oil mixture received in tank; and an outlet in the tank for discharging water separated from oil; wherein one or more oil drain apertures are provided in the side wall of the tank at a pre-determined level above the base of the tank.
2. A separator arrangement of claim 1, wherein a respective adjusting mechanism is provided for adjusting the level of each of the one or more of the oil drain apertures in relation to the base of the tank.
3. A separator arrangement of claim 2, wherein a plurality of said oil drain apertures are provided.
4. A separator arrangement of any preceding claim, wherein the tank comprises a levelling arrangement for adjusting the tilt of the base of the tank in relation to the surface on which the separator arrangement is placed.
5. A separator arrangement of any preceding claim, wherein the tank has a number of consecutively arranged partitions which define oil retention chambers, wherein said one or more oil draining apertures are provided in each chamber.