Liquid treatment apparatus and method of use

Abstract

An apparatus for treating a contaminated liquid and a method of use. The apparatus comprises a housing defining a chamber having a liquid inlet and a liquid outlet. The inlet is arranged in the apparatus to direct a pressurised contaminated liquid into the chamber, a pressure in the chamber being lower than an inlet pressure of the contaminated liquid so that it depressurises in the chamber and separates a contaminant from the contaminated liquid into the chamber. The inlet directs the contaminated liquid in a substantially continuous fluid stream which impacts on an inner surface of the chamber. The inner surface is arranged to cause the fluid stream to flow along the inner surface towards the liquid outlet.

Description

[0001] LIQUID TREATMENT APPARATUS AND METHOD OF USE

[0002] The present invention relates to a liquid treatment apparatus and a method of use. The invention has applications in treating a contaminated liquid, and in particular to removing water from oil.

[0003] Background to the invention

[0004] There are a number of industries in which liquids become contaminated during use or storage and require treatment to enable their use to continue, or for them to be re-used or recycled. For example, the contamination of lubrication oils with water is known to increase the wear on moving parts, which can lead to early breakdowns and failures of parts, and the need for costly replacements and repairs. A number of industries rely on rotary equipment or machinery, for example oil and gas, wind power, manufacturing, marine, pulp and paper, mining and nuclear industries, as well as refineries and process plants for chemicals such as ammonia. Failure of equipment or machinery in such industries, for example the failure of compressors, pumps or turbines, can lead to costly downtime. Additionally, the regular replacement and disposal of contaminated oil can be costly and has a detrimental environmental impact. Even new or virgin oil can be contaminated with water, and in some cases the water content may be too high to avoid risk of breakdowns and failures.

[0005] Systems which address the need for removing contaminants from oil in combustion engines include those which pass contaminated oil through a chamber, from which separated contaminants are removed, so that the treated lubricating can be circulated back into the oil circulation system of the combustion engine. When directing an oil containing a dispersed water phase through a nozzle into a relatively low-pressure chamber, the fluid is de-pressurised as it enters the chamber, and the water phase will separate from the oil phase due to the different thermodynamic properties of the water and oil phases and their different responses to changes in heat and pressure. Lowering the pressure in the chamber further through the use of, for example a vacuum pump, may increase the rate at which the water phase will separate from the oil. A similar effect can also be achieved by increasing the temperature of the fluid as it enters the chamber. Various systems propose to spray the fluid containing oil and water as an atomised mist into a chamber as a means of increasing the rate at which the water phase will separate from the oil phase. When spraying the fluid as a mist into the chamber, the tiny droplets of fluid will have a greater surface area, thereby increasing the rate at which the water phase will be separated from the oil.

[0006] US 4,717,474 describes a system in which contaminated oil is forced upwardly from a pressure chamber through an orifice and into a ventilation chamber. The oil is sprayed from the orifice and atomised when entering the ventilation chamber, thereby causing separation of any contaminants into a gaseous medium in the chamber. The contaminants are then removed from the chamber through a vent.

[0007] WO 2012 / 164348 describes a system for removing alien liquids from a petrochemical product. The petrochemical product is injected into a ventilation chamber through a plurality of atomizing nozzles which spray the petrochemical product into the ventilation chamber as an atomised mist. As the contaminants are separated into a gaseous phase, the gas is vented from an upper part of the chamber through a non-return valve, whilst the collected oil is drained from the bottom of the chamber through a drainage pipe.

[0008] To facilitate the separation of contaminants from the oil, these known systems rely on the atomisation of the contaminated oil as it passes through the nozzle into the chamber. This is known to result in foaming of the oil. When the oil becomes foamed, this can cause complications with the subsequent collection and drainage of the oil from the chamber. The foam may cause a reduced separation efficiency, requiring a larger chamber size to sustain an effective treatment rate. In addition, as a result of the atomisation of the contaminated oil as it enters the chamber, atomised oil may be vented from the chamber along with the separated contaminants, leading to a reduced efficiency.

[0009] WO 2011 / 049468 describes a method for removing water from a contaminated hydraulic oil reservoir by heating the contaminated oil under reduced pressure. The contaminated oil is pumped out of the reservoir through a heating element and into a treatment column. Once in this treatment column, moisture is extracted from the oil through an outlet whilst a reduced pressure is maintained using a vacuum pump. Whilst such systems mitigate issues with foaming, they commonly have a high energy consumption due to their reliance on heating of the oil and their operation at reduced pressure. In addition, the heating of oils can result in the degradation of the oils over time, and this may ultimately lead to the need for the replacement of the oil.

[0010] Summary of the invention

[0011] It is amongst the aims and objects of the invention to provide an apparatus and a method of use treating a contaminated liquid, which is an alternative to the methods and apparatus described in the prior art, or which addresses one or more of the problems or drawbacks of known apparatus and methods.

[0012] It is amongst the aims and objects of the invention to provide an apparatus and a method of use with an improved efficiency and / or effectiveness for separating contaminants from a liquid in comparison to known apparatus and methods.

[0013] Further objects and aims of the invention will become apparent from the following description.

[0014] According to a first aspect of the invention, there is provided an apparatus for treating a contaminated liquid, the apparatus comprising: a housing defining a chamber having a liquid inlet and a liquid outlet;

[0015] - wherein the inlet is arranged in the apparatus to direct a pressurised contaminated liquid into the chamber, a pressure in the chamber being lower than an inlet pressure of the contaminated liquid so that the contaminated liquid depressurises in the chamber;

[0016] - wherein the inlet is configured to direct the contaminated liquid in a substantially continuous fluid stream which impacts on an inner surface of the chamber;

[0017] - wherein the inner surface is arranged to cause the fluid stream to flow along the inner surface towards the liquid outlet; and wherein the apparatus causes separation of a contaminant from the contaminated liquid in the chamber.

[0018] As the fluid stream flows along the inner surface, contaminants in the fluid stream are exposed to a gaseous medium inside the chamber, and preferentially associate with the medium, thereby separating from the contaminated liquid. The gaseous medium may comprise nitrogen, and may be air. In the context of the invention, the term “substantially continuous fluid stream” describes a stream of the contaminated liquid that has a stable, close to stable, and / or steadily increasing or decreasing flow rate, as it flows from the liquid inlet to the inner surface of the chamber, during at least a part of a liquid treatment process. Such a flow regime contrasts with a discontinuous stream of fluid of the spraying or atomisation approaches taught in the prior art. However, it will be appreciated that in embodiments and implementations of the invention, the apparatus may be operated for discrete periods of time, for example for batch treatments, between which the apparatus is not operational and there is no fluid stream. Such modes of operation are within the scope of the invention.

[0019] The apparatus may be configured to ventilate the contaminant from the chamber.

[0020] Preferably, the chamber comprises a ventilation outlet, and the apparatus is configured to ventilate the contaminant from the chamber. The contaminant may be ventilated from the chamber with the gaseous medium as micro-droplets carried in the gas, in the form of an aerosol, or as a vapour or gas.

[0021] The contaminated liquid may comprise a liquid oil phase, and / or the contaminant may comprise water. Alternatively, the contaminated liquid may comprise any carrier liquid contaminated with a contaminant with different thermodynamic and / or polar properties.

[0022] The contaminated liquid may comprise a lubricating oil, and / or may be an oil used in rotary equipment or machinery, and / or in a hydraulic system. In an alternative embodiment, the carrier liquid may comprise an aqueous fluid, and the contaminant may comprise, for example, either ammonia or a cryogenic liquid.

[0023] The chamber may be filled or substantially filled with gas, which may be air.

[0024] The chamber may comprise at least two sub chambers. The at least two sub chambers may comprise at least one liquid sub chamber and at least one ventilation sub chamber. The at least one liquid sub chamber and at least one ventilation sub chamber may be partially separated by at least one wall. The liquid inlet may be located in (one of) the at least one liquid sub chamber. The ventilation outlet may be located in the at least one ventilation sub chambers.

[0025] The inner surface may comprise an impact location for the substantially continuous fluid stream. The impact location may be disposed on the inner surface opposing the liquid inlet. The inner surface may be inclined to the predominant direction of the fluid stream at a shallow angle at the impact location. For example, the impact location the inner surface is inclined to the predominant direction of the fluid stream at an angle of less than 20 degrees, optionally less than 10 degrees, optionally less than 5 degrees.

[0026] The impact location may be on a wall of the chamber. The wall may be disposed between a ventilation sub chamber and a liquid chamber. Alternatively, or in addition, the wall may be a side wall of the chamber. The substantially continuous fluid stream may comprise a stream or jet of the contaminated liquid that passes through a gas contained in the chamber before impacting on the inner surface of the chamber. The stream or jet of the contaminated liquid may pass through a gas contained in the chamber in a substantially vertical direction before impacting on the inner surface of the chamber.

[0027] At the impact location, the inner surface may be curved. A tangent of the curve at the impact location may be a shallow angle to the predominant direction of the fluid stream. A tangent of the curve at the impact location may be approximately parallel to the predominant direction of the fluid stream.

[0028] Preferably, the impact location has a smooth transition to an adjacent inner surface of the chamber. The adjacent inner surface of the chamber may be a roof surface. Where the impact location is on a wall of the chamber, the wall may have a smooth transition to the roof surface of the chamber.

[0029] In embodiments, the impact location is on a curved surface of a wall of the chamber, which has a smooth curved transition to a roof surface of the chamber. The roof surface may comprise a smooth curved transition to an opposing wall of the chamber. The fluid may therefore be directed to flow from the impact location, over the roof surface, to an opposing wall surface. The apparatus may be configured such that the fluid forms a thin film on the inner surface of the chamber as it flows to towards the liquid outlet.

[0030] The apparatus may comprise a flow splitter on an inner surface of the chamber. The flow splitter may be a raised projection which is positioned in the path of the flowing fluid. The flow splitter may be positioned to extend along a plane which is aligned with the direction of fluid flow on the inner surface. The flow splitter may improve the distribution of the fluid over the surface of the fluid chamber. The flow splitter facilitates the fluid flow being more evenly distributed across the surface of the fluid chamber. The flow splitter may be positioned such that the fluid flow is split substantially symmetrically either side of the flow splitter. The flow splitter may be formed in the roof of the chamber.

[0031] The apparatus may comprise a chamber base. The chamber base may be formed to direct liquid towards the liquid outlet. Liquid may flow in a downwards direction towards the liquid outlet.

[0032] The chamber base may comprise at least one smooth planar surface. Alternatively, or in addition, the chamber base may comprise a plurality of steps. The one or more planar surfaces may be inclined to the horizontal.

[0033] The ventilation output may comprise a pump attachment. The apparatus may comprise a pump attached to the pump attachment, which may function to reduce the pressure at the ventilation outlet and / or the chamber. The pump may comprise a vacuum pump, and / or may comprise a venturi pump, which may be connected to a compressed gas or air source.

[0034] The apparatus may comprise a condensing unit for condensing any vaporised contaminants exiting the ventilation outlet.

[0035] The apparatus may comprise a ventilation inlet to the chamber. The ventilation inlet may be used to enable a gas to enter into the chamber. The gas may be air or nitrogen. The inflow of the gas into the chamber may increase ventilation through the chamber, thereby providing more favourable conditions for the removal of separated contaminants from the chamber. The ventilation inlet may be located in a wall of the ventilation chamber. Ventilation from the ventilation sub chamber may be active, assisted by the operation of one or more pumps coupled to a ventilation outlet and / or a ventilation inlet. Alternatively, ventilation may be passive, through a ventilation outlet. Alternatively, or in addition, the apparatus may be configured to be operable in an active mode or a passive mode.

[0036] The apparatus may comprise a heater or a cooler. The heater or cooler may be used to heat or cool one or more components of the apparatus. The apparatus may comprise thermal insulation which may be applied to at least one component of the apparatus. The use of active heating and / or cooling of the apparatus, and / or the use of insulation, may be used to manage the thermodynamic conditions of the system, and / or to keep the viscosity of the fluid within a particular range associated with a desired flow regime.

[0037] The apparatus may comprise a grid plate, which may extend across a lower part of the chamber. The grid plate may be located at a height above a lower surface of the chamber, and / or may be oriented at an angle inclined downwards towards the liquid outlet. The grid plate may contain through-apertures extending from an upper surface to a lower surface of the grid plate, which may be arranged in a one dimensional or two-dimensional array.

[0038] The apparatus may comprise one or more smart surfaces incorporated onto or into particular features or components of the apparatus. The one or more smart surfaces may for example demonstrate hydrophilic, hydrophobic or wear resistant properties.

[0039] According to a second aspect of the invention, there is provided a method of removing contaminants from a fluid, the method comprising using the apparatus of the first aspect of the invention.

[0040] Embodiments of the second aspect of the invention may include one or more features according to the first aspect of the invention or its embodiments, or vice versa.

[0041] According to a third aspect of the invention, there is provided a method of treating a contaminated fluid, the method comprising: directing a pressurised contaminated liquid into a chamber through a liquid inlet, a pressure in the chamber being lower than an inlet pressure of the contaminated liquid so that the contaminated liquid depressurises in the chamber, wherein the inlet directs the contaminated liquid in a substantially continuous fluid stream which impacts on an inner surface of the chamber; flowing the fluid stream along the inner surface towards the liquid outlet; causing separation of a contaminant from the contaminated liquid in the chamber; ventilating a contaminant from the chamber; and removing the treated liquid from the chamber.

[0042] As the fluid stream flows along the inner surface, contaminants in the fluid stream are exposed to a gaseous medium inside the chamber, and preferentially associate with the medium, thereby separating from the contaminated liquid. The gaseous medium may comprise nitrogen, and may be air.

[0043] The contaminated liquid may comprise a liquid oil phase, and / or the contaminant may comprise water. Alternatively, the contaminated liquid may comprise any carrier liquid contaminated with a contaminant with different thermodynamic and / or polar properties (compared with the carrier liquid).

[0044] The method may comprise directing the substantially continuous fluid stream to an impact location on the inner surface, the impact location opposing the liquid inlet.

[0045] The method may comprise flowing the contaminated liquid from the impact location, over the roof surface, to an opposing wall surface.

[0046] The method may comprise flowing the fluid as a thin film on the inner surface of the chamber towards the liquid outlet.

[0047] Embodiments of the third aspect of the invention may include one or more features according to the first or second aspects of the invention or their embodiments, or vice versa.

[0048] According to a fourth aspect of the invention, there is provided an apparatus for treating a contaminated liquid, the apparatus comprising: a housing defining a chamber having a liquid inlet and a liquid outlet; - wherein the chamber comprises a liquid sub chamber and a ventilation sub chamber, the liquid sub chamber and ventilation sub chamber being partially separated from one another by a wall;

[0049] - wherein the inlet is arranged to direct a pressurised contaminated liquid into the liquid sub chamber, so that it depressurises in the chamber;

[0050] - wherein the ventilation sub chamber comprises at least one ventilation output for removing separated contaminants from the apparatus; and wherein the apparatus causes separation of a contaminant from the contaminated liquid in the chamber.

[0051] The wall may assist with directing the pressurised contaminated liquid towards the liquid sub chamber and away from the ventilation sub chamber. The inlet may direct the contaminated liquid in a substantially continuous fluid stream which impacts on an inner surface of the chamber, which may be a part of the wall. The inner surface may be arranged to cause the fluid stream to flow along the inner surface towards the liquid outlet.

[0052] Embodiments of the fourth aspect of the invention may include one or more features according to the first to third aspects of the invention or their embodiments, or vice versa.

[0053] Brief description of the drawings

[0054] There will now be described, by way of example only, various embodiments of the invention with reference to the drawings, of which:

[0055] Figure 1 is a sectional view through an apparatus according to an embodiment of the invention;

[0056] Figure 2 is a partial sectional view taken along the line X-X’ of Figure 1 , viewed in a direction denoted by arrow A;

[0057] Figures 3A to 3C are schematic representations of the operation of the apparatus of Figures 1 and 2;

[0058] Figure 4 is a partial sectional view of an apparatus for removal of water from a lubricating oil, according to an alternative embodiment of the invention; Figure 5 is a plan view of the top unit of the apparatus of Figure 4; and

[0059] Figure 6 is a partial sectional view of an apparatus for removal of water from a lubricating oil, according to an alternative embodiment of the invention.

[0060] Detailed description of preferred embodiments

[0061] By way of example, embodiments of the invention will be described in the context of removing water from oil, such as lubricating oil that may be used in rotary equipment or hydraulic systems. It will be appreciated that in at least some of its aspects and embodiments, the invention is generally applicable to removing contaminants which are mixed with or otherwise entrained in a fluid, where the contaminant and the fluid have different thermodynamic and / or polar properties.

[0062] Referring firstly to Figures 1 and 2, there is shown generally at 100 an apparatus for removing water from oil according to an embodiment of the invention. Figure 1 is a sectional view, through the apparatus, and Figure 2 is a partial cross-sectional view of apparatus 100, taken along the line X-X’ of Figure 1 , and viewed in a direction denoted by arrow A.

[0063] The apparatus 100 comprises a top unit 101 and a base unit 102 which are separable at line 103, allowing for the assembly and disassembly of the apparatus 100. The top unit 101 and the base unit 102 are assembled together to form a chamber, shown generally at 104. The top unit 101 and bottom unit 102 are, in this example, fabricated from aluminium, which may be cast or milled to form the required shape. Other materials and / or fabrication methods may be used in alternative embodiments of the invention.

[0064] The chamber is filled or substantially filled with gas, which may be air.

[0065] In use, a contaminated oil is directed into the chamber 104 through a fluid inlet 108 in a substantially continuous and pressurised stream of liquid oil containing relatively small amounts of water. Within the chamber 104, water contaminants present in the fluid stream are separated from the liquid. The separated contaminants are vented from the chamber 104, and liquid oil component is collected and removed. The apparatus and process, which will be described in more detail below, have been found to be surprisingly effective at removing very small amounts of water and therefore prolonging the life of the oil and preventing failures and breakdowns of machinery components.

[0066] The chamber 104 is a continuous volume defined by the inner surfaces of the top unit and base unit. The base unit comprises a lower surface 124 defining a series of steps 120. An inclined ramp 114 leads downwards from the uppermost part of the side 125 of the base unit and the steps 120. The steps 120 drop down from a first height adjacent the ramp 114 to a second height adjacent a trough 123. The trough is fluidly connected to a liquid outlet 122, and in this embodiment is adjacent the second side wall of the chamber.

[0067] Figure 2 shows the steps 120 and edges 121 of the steps over which the oil flows from above, as well as the channel 123. The steps 120 may have a curvature in a horizontal plane. This curvature may be is centred around the fluid inlet 108, such that the curvature of the steps is symmetrical about the line 140 passing through the fluid inlet 108.

[0068] The chamber 104 comprises a wall portion 126 dividing a liquid sub chamber 105 from a ventilation sub chamber 107, which are horizontally adjacent to one another. The wall portion 126 extends downwards from the upper part of the chamber 104 (i.e. within the top unit), but does not reach the floor of the chamber, so that the sub chambers are connected. On the liquid sub chamber side 105 of the wall portion, the wall portion transitions into the sub chamber roof 106. In preferred embodiments, the transition between the side 127 and the roof 106 is a continuous curved profile (i.e. without any discontinuities or sharp changes in gradient) to facilitate a smooth flow of liquid.

[0069] The fluid inlet 108 comprises a nozzle or orifice 170 connected to an inlet conduit 171 , which in turn is connected to a source of contaminated fluid to be treated. The nozzle is positioned and oriented to direct the flow of fluid towards an impact location 109 on the inner surface of the chamber, located in the liquid sub chamber. The impact location 109 is vertically above the fluid inlet 108 and nozzle 170, as shown by dashed line 110, which indicates the direction of the fluid stream. The surface at the impact location 109 is on the wall portion and is inclined with respect to the axis of the fluid stream at a shallow angle, so that the flow direction will be deviated only slightly from the fluid stream direction on impact. Towards the side of the liquid chamber opposite the wall portion, the inner surface transitions from the roof to a vertical side wall 113. The transition between the roof 106 and the side 113 is a continuous curved profile (i.e. without any discontinuities or sharp changes in gradient) to facilitate a smooth flow of liquid.

[0070] The ventilation sub chamber extends from the wall portion 126 to an outer wall of the apparatus defined by side walls 180 and 181 of the top unit and base unit respectively. The inner surface of the roof 182 of the ventilation chamber is substantially horizontal and comprises a ventilation outlet 130 with a vacuum pump attachment 131 driven by a compressed air source (not shown) attached at 132. The ventilation sub chamber has curved transitional surfaces between the wall portion 126 and side wall 180 to facilitate flow of gases towards the ventilation outlet 130. The apparatus 100 also comprises a ventilation inlet 133 which can optionally be used to allow air or gas to enter the chamber 104, thereby increasing ventilation through the chamber 104.

[0071] Figures 3A to 3C are schematic representations of the process by which water is separated from the lubricating oil when using apparatus 100. The fluid is depressurised as it enters the chamber, and the water phase will associate with a gaseous medium in the chamber in preference to the oil phase as a result of the different thermodynamic and polarization properties of the water and oil phases. The inventive apparatus seeks to promote the separation of water from the fluid by increasing the surface area of the fluid while mitigating drawbacks and deficiencies associated with the prior art.

[0072] The fluid is injected into the chamber in the form of a substantially continuous stream of fluid that passes through the air in the chamber. This is in contrast to prior art proposals in which a fluid containing oil and water are sprayed as an atomised mist into a chamber as a means of increasing the rate at which the water phase will separate from the oil phase. When spraying the fluid as a mist into the chamber, the tiny droplets of fluid will have a much greater surface area, increasing the rate at which the water phase will be separated, but issues which result from spraying the fluid into the chamber in the form of an atomised mist include significant foaming of the fluid.

[0073] Embodiments of the present invention enable a thin film of fluid to be formed to promote effective separation of the water phase from the oil without the need for the atomisation of the fluid. The apparatus may be configured so that the thin film extends across the internal surfaces of the fluid sub chamber 105 and the lower surface 124 of the base unit. This formation of the thin fluid film across the internal surfaces of the apparatus has been found to be surprisingly effective at promoting the separation of the water phase from oil, with reduced foaming issues and without relying on fluid heating.

[0074] Figure 3A shows generally at 200 the passing of a pressurised contaminated fluid containing a continuous phase of lubricating oil 201 and a dispersed water phase 202 from the nozzle 170 of apparatus 100 into the chamber 104. Without wishing to be bound by theory, after the fluid has entered the chamber 104, the water phase will begin to preferentially associated with gas within the chamber, in the form of clouds of water microdroplets 203. Preferably, the fluid is directed from the nozzle 170 in the form of a continuous stream of laminar fluid flow. The fluid is de-pressurized as it exits the nozzle 170, and the water droplets 202 will expand in comparison to the oil phase 201. This expansion will result in the water droplets 202 merging. The polar attraction between air and water is also much higher than the polar attraction between oil and water, resulting in the water droplets 202 migrating towards the interface 204. The water droplets 202 will also absorb some of the surrounding chamber gas or air, further contributing to their expansion. As the water phase droplets 202 merge and expand, the droplets closest to the interface 204 between the contaminated oil and the surrounding chamber gas will separate from the oil and into the gas within the chamber. In addition, due to the high polar attraction between water molecules, some of the droplets of the water phase will merge as the fluid flows through the fluid inlet 108 and into the chamber 104.

[0075] Water present in the oil will also preferentially associate with any air trapped in the liquid oil (which in some cases may be up to 10% by volume). As the liquid flows from the nozzle into the chamber, the trapped air is also decompressed, and will transfer out of the oil phase and into the gas within the chamber, assisting the separation of the water from the oil.

[0076] Figure 3B shows generally at 210 the impact of the fluid stream with an inner surface of the liquid sub chamber 105. The fluid stream impacts the surface at a location 109 on a side 127 of the wall portion 126. The fluid exits the fluid nozzle 170 in the form of a continuous stream of laminar fluid flow in stage 200, and the fluid will still be a substantially continuous stream of fluid as it impacts with the side 127 of liquid sub chamber 105. The lower end 111 of the side wall 127 is vertically lower than impact location 109 to prevent fluid from being directed into the ventilation sub chamber. The angle of the inclination of the inner surface at the impact location is shallow, so that on impact there is only a slight deviation of the flow direction from the direction of the fluid stream. By designing the curvature of the side wall 127 in this manner, the initial impact forces between the fluid stream and the side wall 127 are minimised, leading to the continuity of flow across the inner surfaces of the liquid sub chamber 105 to minimise turbulence and disruption to the flow such as splashing and the forming of droplets.

[0077] When the fluid stream impacts with the side wall 127, it will begin spread across the inner surface, as the fluid flows along the surface of the liquid chamber from the impact location 109 across the roof 106 and to the vertical side wall 113. As the fluid flows, it spreads in a direction transverse to the main flow direction as a thin film of fluid. As the fluid spreads out into a thin film, the water phase droplets 201 will become positioned closer to the interface 204 between the oil and the surrounding chamber gas and will separate from the oil into the gas.

[0078] The inner surfaces of the liquid sub chamber 105 generally define a smoothly curved surface between a first end 111 and a second end 112 to encourage the fluid to flow smoothly from the impact point 109 to the second end 112. In this example, the curvature of the inner surface between the first end 111 and the uppermost point of the roof 106 follows that of an ellipse, with a gradient which increases towards the uppermost point of the roof 106. Between the uppermost point of the roof 106 and the second end 112, the curvature of the inner surface approximately follows that of an arc of a circle. Following the impact of the fluid flow with the side wall 127 and the formation of a thin film of fluid extending to the second end 112, the fluid will then flow down the vertical wall 113 of the liquid sub chamber 105. The inclined ramp 114 then leads the fluid to steps 120 in the base unit 102.

[0079] Figure 3C illustrates generally at 220 the flow of fluid down the steps 120 of the apparatus 100 by gravity. As the fluid flows over the edges 121 of the steps 120, the thickness of the fluid film reduces, and the water droplets are brought closer to the interface 204 between the oil and the surrounding chamber gas. This process results in the separation of the water phase from the oil into the gas. After the flow of the fluid down the steps 120 of the apparatus 100, the oil will be collected in the trough 123 and then will drain out of the liquid outlet 122. In operation, the water phase 201 is released as micro-droplets 203 or water or in the form of an aerosol, and is drawn out of the chamber 104 through the ventilation outlet 130. This can be promoted by flowing air or gas from a pressurised source through the air attachment 132 to draw water 203 from the chamber 104 through the Venturi effect. The water will then be expelled from through the outlet 130, optionally to a condenser unit.

[0080] Alternatively, or in addition, a vacuum pump may be attached to the vacuum pump attachment 131 for removing gas and water 203 from the chamber. The vacuum pump may also be used for reducing the pressure within the chamber 104 to below atmospheric pressure, which may provide more favourable conditions for the separation of the water phase from the oil.

[0081] The ventilation inlet 133 can also optionally be used to allow air or gas to enter the chamber 104, thereby increasing ventilation through the chamber 104.

[0082] The apparatus 100 is configured so that the fluid is directed from the nozzle 170 into the chamber 104 in the form of a substantially continuous stream of fluid to promote substantially smooth or laminar flow through the apparatus during separation of water from the oil phase. -In contrast, in prior art configurations, the fluid is injected into a chamber in the form of a spray of oil and water, such as in the form of an atomised mist. The inventors have recognised that there a number of issues associated with the prior art have been addressed through their approach of promoting smooth or laminar fluid. In particular, injecting an atomised mist of oil and water into a chamber will results in foaming of the fluid. This may require dedicated approaches to foam management and / or dissipation in the apparatus. Extensive foaming will also result in a reduced separation rate of the water phase and may require a larger chamber size to account for the reduced rate. In addition, by forming an atomised mist of oil and water in the chamber, there is a greater likelihood that the extracted water will be contaminated with oil. There may also be difficulties associated with the collection and subsequent drainage of the oil from the chamber.

[0083] A further advantage of the invention is that the apparatus 100 is configured so that it may operate without additional heating being provided to components of the apparatus 100 or to the oil which is input into the apparatus 100. Whilst some heat may be provided to the oil that is input into the apparatus 100, this is typically kept to a minimal. As such, the apparatus works well with oils at ambient or low temperatures. In contrast, for the prior art methods, oil temperatures above ambient, for example in the range of 40 to 80 degrees C are desirable to facilitate atomisation and separation of the fluid, and the elevated temperatures may exacerbate foaming problems. Heating may be necessary to reach the desirable temperature ranges for atomisation. Disadvantages associated with heating include increased energy consumption requirements and reduced operating lifetime of the oil, due to repeated and / or extreme heating leading to the degradation of the oil over time.

[0084] Figures 4 and 5 are views of an apparatus 300, according to a preferred embodiment of the invention. Figure 4 is a part-section taken along the line Y-Y’ of Figure 5 viewed in a direction denoted by arrow B, and Figure 5 is a plan view of the top unit of the apparatus of Figure 4. The plan view shown in Figure 5 is taken along the line Z-Z’ of Figure 4, and viewed in a direction denoted by arrow C. Whilst the ventilation outlet 330 and ventilation inlet 333 should not strictly be present in a sectional view of Figure 4, they are included for illustrative purposes.

[0085] The apparatus 300 is similar to apparatus 100 both in structure and function, with like features indicated by like reference numerals incremented by 200. Similarly to apparatus 100, apparatus 300 comprises a top unit 301 and a base unit 302 which are distinct units that separate at line 303. Bolt holes 355 pass through an upper flange 357 and lower flange 356 which are connected to the top unit 301 and a base unit 302, respectively, facilitating this disassembly and assembly of the apparatus 300. Figure 5 is a plan view of the top unit 301 , following its disassembly from the base unit 302.

[0086] In contrast to apparatus 100, the chamber 304 of apparatus 300 comprises two liquid sub chambers 305a and 305b, as will be understood from Figure 5. Similarly to apparatus 100, there is a single ventilation sub chamber 307. The liquid sub chambers 305a and 305b are similar in structure and function to one another and are similar to the liquid sub chamber 105 of apparatus 100.

[0087] The liquid sub chambers 305a and 305b, and the ventilation sub chamber 307, are spaced horizontally from one another. At the upper part of the chamber 304 (i.e. within the top unit), the respective liquid sub chambers are separated from the ventilation sub chamber 307 by wall portions 326a and 326b. Liquid sub chambers 305a and 305b are separated from each other by a liquid sub chamber wall 360 in the top unit 301, which partially extends across the space defined between the two liquid sub chambers.

[0088] Apparatus 300 comprises two fluid inlets 308a and 308b, as well as two fluid nozzles 370a and 370b, which direct fluid into each of the liquid sub chambers 305a and 305b respectively. For liquid sub chamber 305a, the nozzle 370a directs the fluid into the liquid sub chamber 305a to impact with the side wall 327a at the approximate impact location 309a. The impact location 309a is at a point vertically above the fluid inlet 108a, as shown by dashed line 310a. The liquid sub chamber wall 360 functions to prevent or minimise fluid that is directed from nozzle 370a from entering liquid sub chamber 305b, and similarly will function to prevent or minimise fluid that is directed from nozzle 370b from entering liquid sub chamber 305a.

[0089] Each of the liquid sub chambers 305a and 305b also incorporates a flow splitter 341a and 341b, respectively. The purpose of the flow splitters 341 is to improve the distribution of the fluid over the inner surfaces of the respective liquid sub chambers.

[0090] The flow splitter 341a is arranged so that it is symmetrical about the line Y-Y’ and is positioned such that it lies in the path of the fluid following its impact with impact point 309a. The flow splitter 341a is connected to the inner surface of liquid sub chamber 305a, extending from the side wall 327a and across the roof 306a of the liquid sub chamber. The flow splitter 341a comprises a raised projection 342a which tapers outwardly in a horizontal direction as it extends across the inner surface of liquids sub chamber 305a and towards the second end 312a. The prominence of the raised projection 342a also increases in height as the flow splitter extends from the side wall 327a towards the second end 312a. Towards the second end 312a, the prominence of the flow splitter begins to decrease in in height as the flow splitter 341a joins with the inner surface of the liquid sub chamber 305a.

[0091] The apparatus 300 is symmetrical about the line 350 shown in Figure 5. As such, liquid sub chamber 305b comprises the same features and is configured to function similarly to liquid sub chamber 305a.

[0092] The apparatus 300 comprises two liquid sub chambers 305a and 305b but a single ventilation chamber 307. Whilst this is the preferred embodiment, the inventors also recognise that the apparatus 300 may comprise any number of liquid sub chambers 305 and any number of ventilation sub chambers 307. Additionally, a plurality of apparatus 300 may be arranged side-by-side and operated simultaneously such that cumulatively the plurality of apparatus 300 may process a higher volume of fluid at a particular time.

[0093] The process described with reference to Figures 3A to 3C is also applicable for apparatus 300. In use, a contaminated oil is directed into the chamber 304 through fluid inlets 308a and 308b in substantially continuous and pressurised streams of liquid oil containing relatively small amounts of water. Within the chamber 304, water contaminants are separated from the fluid stream and separated from the liquid. The separated contaminants are vented from the chamber 304 through the ventilation outlet 330, and liquid oil component is collected and removed.

[0094] Following the impact of the fluid flow with the side walls 327a and 327b, it will spread out into thin films of fluid which flow across the inner surfaces of the liquid sub chambers 305a and 305b. Preferably, the fluid films will extend from the side walls across the sub chamber roofs 306a and 306b, and to the vertical side wall 113. Similarly to apparatus 100, apparatus 300 is configured to maximise the surface area of the liquid sub chambers over which the fluid will spread. In addition to the features described with respect to apparatus 100, this is also facilitated by the use of the flow splitters 341a and 341b into the respective liquid sub chambers. The fluid flow will be divided as it comes into contact with the flow splitters 341a and 341b, and this will contribute to the spreading out and the formation of a thin film of fluid over the inner surfaces of the respective liquid sub chambers. As the fluid spreads out across the inner surfaces of the liquid sub chambers, the liquid sub chamber wall 360 minimises the interference between the fluid that is directed into each of the respective liquid sub chambers 305a and 305b.

[0095] As the fluid film reaches the second ends 312a and 312b of each liquid sub chamber, the fluid will then flow down the vertical wall 313 of the chamber 304, similarly to apparatus 100. The inclined ramp 314 leads the fluid to steps 320 in the base unit 302. The fluid will flow down the series of steps from the first height adjacent to the ramp 314 to a second height adjacent to the trough 323. The trough is fluidly connected to a liquid outlet 322, allowing for the removal of the collected oil from the apparatus 300. Referring now to Figure 6, there is shown in part-sectional view an apparatus 300’ for removal of water from a lubricating oil, according to an alternative embodiment of the invention. The apparatus is similar to the apparatus 100 and 300, with like features given like reference numerals, and its features and function will be understood from the description of Figures 1 to 5. The apparatus 300’ differs from previous embodiments in that it includes a grid plate 390 extending across a lower part of the chamber, at a height above the chamber lower surface, at an angle inclined downwards towards the liquid outlet. The grid plate 390 contain a two-dimensional array of through-apertures 392 extending from an upper surface to a lower surface of the grid plate, which allow separated contaminants to flow through the grid plate from the base of the chamber towards the ventilation outlet. Diameters of the through apertures may be in the range of 1 mm to 8 mm. The grid plate 390 of this embodiment extends across the full area of the chamber, but in alternative embodiments, the grid plate may extend across one or more parts of the chamber. Alternatively, or in addition, multiple grid plates may be provided. The grid plate 390 provides an additional surface for the fluid film to form on and / or flow across. By providing an additional surface area for the fluid film, the separation of contaminants may be increased and issues relating to foaming may also be reduced. In addition, water and / or air bubbles present in the liquid will effectively be split or filtered by the grid plate as the oil passes over the edges formed by the apertures. As the fluid flows over the edges, the water droplets and trapped air are brought closer to the interface between the oil and the surrounding chamber gas, assisting with the separation of the water phase from the oil into the gas.

[0096] The apparatus 300’ is also provided with one or more surfaces (not shown) for improved performance of the apparatus. The surfaces may be created by special selection of materials, or by coating parts of the apparatus with functional coatings. For example, the inner surface of the chamber at the impact point may be provided with a wear resistant coating or may be formed from a wear resistant material, to reduce wear on the chamber caused by impact of the fluid stream. Flow surfaces of the chamber may be selectively provided with hydrophilic or hydrophobic coatings (or may be formed from hydrophilic or hydrophobic materials) to cause preferential movement or flow of oil phases and water phases through the apparatus, and thereby promote separated of water into the chamber by disturbing the fluid phases. As an example, the steps and / or grid plate may be designed to have hydrophilic and / or hydrophobic properties. Hydrophilic and hydrophobic surfaces may be provided in different regions of the apparatus, for example on alternating regions of an inner surface.

[0097] The apparatus may include a smart surface incorporated onto particular features of the apparatus. Alternatively, particular features of the apparatus may be designed to include the smart surface. These smart surfaces may, for example, demonstrate hydrophilic, hydrophobic or wear resistant properties, and these properties may be selected as required by the operator. Alternatively, the smart surface may demonstrate both hydrophilic and hydrophobic properties across different regions of the smart surface. This may be across alternating regions of the smart surface. An example coating is PTFE.

[0098] In the embodiments of the invention described above, the base unit 102 comprises steps 120. In variations to the described embodiments, the base unit 102 may a greater or lesser number of steps, and / or may have one or more smooth surfaces which are angled to allow the fluid to flow under gravity to reach the liquid outlet 122. In further variations, features of the described embodiments may be combined. For example, a flow splitter such as described with reference to Figures 4 and 5 may be used in the single liquid sub chamber embodiment of Figures 1 and 2. Similarly, the flow splitter described with reference to Figures 4 and 5 may be omitted from the apparatus, so that each liquid sub chamber has a smooth inner surface similar to the liquid sub chamber of apparatus 100.

[0099] Various design and operational parameters of the apparatus may be selected to improve its performance. These may include one or more of the volume, dimensions or shape of the chamber; the relative dimensions of the liquid sub chamber and ventilation chambers; the pressure of the liquid through the inlet; the flow velocity through the inlet; the curvature of the inner surfaces of the chamber; the angle at which the liquid stream impacts inner surface of the chamber; the dimensions and angle of inclination of the steps; the properties of the fluid, such as its temperature or viscosity; the ventilation and / or addition of gas flow through the chamber; and the pressure and / or temperature within the chamber.

[0100] The inventors have found that the apparatus performs exceptionally well at removing even small amounts of water from a contaminated oil across a range of design and operational parameters. The liquid inlet pressure may for example be within the range of 2 Bar to 20 Bar (200 kPa to 2000 kPa). In embodiments, the liquid inlet pressure may be within the range of 4 Bar to 15 Bar (400 kPa to 1500 kPa).

[0101] The total flow rate of liquid into the chamber may be within the range of 1 to 10 litres per minute, embodiments, the total flow rate may be within the range of 1 to 5 litres per minute.

[0102] The apparatus may operate within an environment where the temperature externally to the apparatus is within the range of -10 °C to 100 °C. In embodiments, the apparatus may operate within an environment where the temperature externally to the apparatus is within the range of 20 °C to 70 °C.

[0103] Where steps are present in the chamber, the height of each step may be within the range of 3 mm to 8 mm. In embodiments, the height of each may be within the range of 3 mm to 5mm. An angle of inclination of the chamber base may within the range of 1 to 25 degrees. In embodiments, the angle of inclination of the chamber base may be within the range of 3 to 15 degrees.

[0104] The total volume of the chamber may be within the range of 1000 to 5000 cm3.

[0105] The volume of the liquid sub chamber(s) (as determined by an artificial division at the wall between the liquid and ventilation sub chambers) may be within the range of 75 cm3to 200 cm3. In embodiments, the volume of the liquid sub chamber may be within the range of 75 cm3to 150 cm3. The volume of the liquid sub chamber may be approximately 25 % to 40 % of the total volume of the chamber.

[0106] The apparatus in the described embodiments had one or two inlet nozzles, but in other embodiments the apparatus may comprise one to ten inlet nozzles. In a preferred embodiment, the apparatus may comprise one to three inlet nozzles. The number of inlet nozzles may correspond to the number of liquid sub chambers. The apparatus may comprise one to ten fluid chambers. In a preferred embodiment, the number of fluid chambers may be in the range of one to three. The at least one inlet nozzle may have an internal diameter within the range of 0.5 mm to 10 mm. In a preferred embodiment, the at least one inlet nozzle may have an internal diameter within the range of 1 mm to 8 mm.

[0107] A plurality of apparatus may be operated in series or in parallel.

[0108] The chamber may be at atmospheric pressure. In an alternative embodiment, the chamber may be at a reduced pressure relative to atmospheric pressure.

[0109] The viscosity of the contaminated liquid may be within the range of 1 to 660 centistokes (cSt). In a preferred embodiment, the viscosity of the liquid may be within the range of 20 cSt to 220 cSt.

[0110] The invention provides an apparatus for treating a contaminated liquid and a method of use. The apparatus comprises a housing defining a chamber having a liquid inlet and a liquid outlet. The inlet is arranged in the apparatus to direct a pressurised contaminated liquid into the chamber, a pressure in the chamber being lower than an inlet pressure of the contaminated liquid so that it depressurises in the chamber and separates a contaminant from the contaminated liquid into the chamber. The inlet directs the contaminated liquid in a substantially continuous fluid stream which impacts on an inner surface of the chamber. The inner surface is arranged to cause the fluid stream to flow along the inner surface towards the liquid outlet.

[0111] In an aspect of the invention, the apparatus comprises a housing defining a chamber having a liquid inlet and a liquid outlet. The chamber comprises a liquid sub chamber and a ventilation sub chamber, the liquid sub chamber and ventilation sub chamber being partially separated from one another by a wall. The inlet is arranged to direct a pressurised contaminated liquid into the liquid sub chamber, so that it depressurises in the chamber and separates a contaminant from the contaminated liquid into the chamber.

[0112] The ventilation sub chamber comprises at least one ventilation output for removing separated contaminants from the apparatus.

[0113] While the foregoing description relates primarily to the separation of water from a liquid oil that is contaminated with water (including a new or virgin oil), it will be appreciated that in at least some of its aspects and embodiments, the invention is generally applicable to removing other contaminants which are mixed with or otherwise entrained in a liquid with different thermodynamic and / or polar properties (for example an aqueous fluid contaminated with a contaminant such as ammonia or a cryogenic liquid). Various modifications to the above-described embodiments may be made within the scope of the invention, and the invention extends to combinations of features other than those expressly claimed herein.

Claims

Claims1 . An apparatus for treating a contaminated liquid, the apparatus comprising: a housing defining a chamber having a liquid inlet and a liquid outlet; wherein the inlet is arranged in the apparatus to direct a pressurised contaminated liquid into the chamber, a pressure in the chamber being lower than an inlet pressure of the contaminated liquid so that the contaminated liquid depressurises in the chamber; wherein the inlet is configured to direct the contaminated liquid in a substantially continuous fluid stream which impacts on an inner surface of the chamber; wherein the inner surface is arranged to cause the fluid stream to flow along the inner surface towards the liquid outlet; and wherein the apparatus causes separation of a contaminant from the contaminated liquid in the chamber.

2. The apparatus according to claim 1 , wherein the chamber comprises a ventilation outlet, and the apparatus is configured to ventilate the contaminant from the chamber.

3. The apparatus according to claim 1 or claim 2, wherein the contaminated liquid comprises a liquid oil phase, and the contaminant comprises a water phase.

4. The apparatus according to any preceding claim, wherein the chamber comprises at least one liquid sub chamber and at least one ventilation sub chamber, the at least one liquid sub chamber and the at least one ventilation sub chamber partially separated by at least one wall.

5. The apparatus according to claim 4, wherein the liquid inlet is located in the at least one liquid sub chamber, and wherein the ventilation outlet is located in the at least one ventilation sub chamber.

6. The apparatus according to any preceding claim, wherein the inner surface comprises an impact location for the substantially continuous fluid stream disposed on the inner surface opposing the liquid inlet.

7. The apparatus according to claim 6, wherein at the impact location the inner surface is inclined to the predominant direction of the fluid stream at an angle of less than 20 degrees, optionally less than 10 degrees.

8. The apparatus according to claim 6 or claim 7, wherein the impact location is on a wall of the chamber.

9. The apparatus according to any of claims 4 to 8, wherein the wall is disposed between a ventilation sub chamber and a liquid chamber.

10. The apparatus according to any of claims 6 to 9, wherein at the impact location, the inner surface is curved, and wherein a tangent of the curve at the impact location is inclined to the predominant direction of the fluid stream at an angle of less than 20 degrees, optionally less than 10 degrees.

11. The apparatus according to claim 10, wherein the tangent of the curve at the impact location is approximately parallel to the predominant direction of the fluid stream.

12. The apparatus according to any of claims 6 to 11 , wherein the impact location has a smooth transition to an adjacent inner surface of the chamber.

13. The apparatus according to claim 12, wherein the adjacent inner surface of the chamber is a roof surface.

14. The apparatus according to claim 13, wherein the roof surface comprises a smooth curved transition to an opposing wall of the chamber.

15. The apparatus according to any preceding claim, configured such that the fluid forms a thin film on the inner surface of the chamber as it flows to towards the liquid outlet.

16. The apparatus according to any preceding claim, comprising a flow splitter on an inner surface of the chamber, the flow splitter comprising a raised projection which is positioned in the path of the flowing fluid.

17. The apparatus according to claim 16, wherein the flow splitter is formed in the roof of the chamber.

18. The apparatus according to any preceding claim, comprising a chamber base comprising a plurality of steps.

19. The apparatus according to any of claims 2 to 18, comprising a pump attached to a pump attachment, which functions to reduce the pressure at the ventilation outlet and / or the chamber.

20. The apparatus according to any of claims 2 to 19, comprising a condensing unit for condensing any vaporised contaminants exiting the ventilation outlet.

21. The apparatus according to any preceding claim, comprising a ventilation inlet to the chamber.

22. The apparatus according to any preceding claim, comprising a heater or a cooler.

23. The apparatus according to any preceding claim, comprising a grid plate extending across a lower part of the chamber, the grid plate containing through-apertures extending from an upper surface to a lower surface of the grid plate, arranged in a one dimensional or two-dimensional array.

24. The apparatus according to any preceding claim, comprising one or more smart surfaces incorporated onto or into components of the apparatus, wherein the one or more smart surfaces demonstrate hydrophilic, hydrophobic or wear resistant properties.

25. A method of removing contaminants from a fluid, the method comprising using the apparatus of any of claims 1 to 24.

26. A method of treating a contaminated fluid, the method comprising: directing a pressurised contaminated liquid into a chamber through a liquid inlet, a pressure in the chamber being lower than an inlet pressure of the contaminated liquid so that the contaminated liquid depressurises in the chamber, wherein theinlet directs the contaminated liquid in a substantially continuous fluid stream which impacts on an inner surface of the chamber; flowing the fluid stream along the inner surface towards the liquid outlet causing separation of a contaminant from the contaminated liquid in the chamber; ventilating a contaminant from the chamber; and removing the treated liquid from the chamber.

27. The method according to claim 26, wherein the contaminated liquid comprises a liquid oil phase, and the contaminant comprises a water phase.

28. The method according to claim 26 or claim 27, comprising directing the substantially continuous fluid stream to an impact location on the inner surface, the impact location opposing the liquid inlet.

29. The method according to claim 28, comprising flowing the contaminated liquid from the impact location, over a chamber roof surface, to an opposing wall surface.

30. The method according to any of claims 26 to 29, comprising flowing the fluid as a thin film on the inner surface of the chamber towards the liquid outlet.

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