Separator

Abstract

A separator for separating contaminants floating in an exhaust stream is disclosed. The separator includes an inlet conduit configured to receive an exhaust stream containing contaminants from a decontamination device and flowing in a first main direction from a lower portion of the separator toward an upper portion of the separator; a spray nozzle configured to spray a entrainment fluid into the inlet conduit in the first main direction to entrain contaminants in the exhaust stream; a first flow direction conversion structure positioned downstream of the inlet conduit; and a first separation conduit positioned downstream of the first flow direction conversion structure. The first flow direction conversion structure is configured to convert the flow of the exhaust stream and the entrainment fluid from an axial flow from the inlet conduit into a circumferential flow in a second main direction opposite to the first main direction in the first separation conduit. In this way, by changing the direction of the flow, a longer flow path can be formed while minimizing the installation area and dimensions of the separator, thereby promoting the separation of the contaminants entrained by the entrainment fluid from the exhaust stream. Further, this can provide a separator that exhausts an exhaust containing less entrainment fluid than a conventional Venturi-ejector type scrubber. Thereby, the need for additional devices such as a cyclone separator that increases the cost and size of the device can be eliminated.

Description

Technical Field

[0001] The field of the present invention relates to a separator.

Background Art

[0002] Separators are known. A separator can be used to separate contaminants floating in a fluid stream. Although such separators exist, they may have drawbacks. Therefore, it is desirable to provide an improved separator.

Summary of the Invention

Means for Solving the Problems

[0003] According to a first aspect, there is provided a separator for separating contaminants floating in an exhaust stream, the separator comprising: an inlet conduit configured to receive an exhaust stream containing contaminants and flowing in a first main direction from the lower part to the upper part of the separator from a decontamination device; a spray nozzle configured to spray a companion fluid into the inlet conduit in the first main direction to entrain the contaminants in the exhaust stream; a first flow direction conversion structure positioned downstream of the inlet conduit; and a first separation conduit positioned downstream of the first flow direction conversion structure, wherein the first flow direction conversion structure is configured to convert the flow of the exhaust stream and the companion fluid from an axial flow from the inlet conduit into a circumferential flow in a second main direction opposite to the first main direction in the first separation conduit.

[0004] The first aspect recognizes that a Venturi scrubber typically includes a Venturi tube, which itself comprises a first converging section, optionally a parallel-sided throat section, and a subsequent diverging section, and is combined with some means of introducing a liquid phase flow. The liquid phase flow input can be positioned upstream or at the throat and can include spray nozzles, shower heads, or overflow weirs. Venturi scrubbers have long been used as a means of turbulently mixing multiple phases (gas - liquid, gas - particle - liquid) for the purpose of transferring substances from one phase to another. In the case of a gas - liquid mixture, it is often done to facilitate the transfer of a water - soluble gas, which is generally a minor component of the gas mixture, into the liquid phase. The liquid phase is often water, but other liquids and solutions such as alkaline compounds, for example, a solution of lime (CaO), are used for acid scrubbing or enhancing the desulfurization process. In the case of gas - particle - liquid, the purpose is generally to transfer particles, which can be solid dust particles (dust removal) or liquid droplets (mist removal), from the gas phase to the liquid phase. A Venturi scrubber can be classified into one of two configurations depending on how the fluid motive force is applied to the system. The first configuration, generally simply called a Venturi scrubber, uses a Venturi tube into which liquid is introduced under low to medium pressure. As the multiphase mixture passes through the Venturi tube, the multiphase mixture undergoes turbulent mixing. The hydrostatic pressure inside the Venturi throat decreases as the fluid velocity increases (Bernoulli's principle), and there is an overall pressure drop from the inlet to the outlet of the Venturi tube. The degree of turbulence, and thus the efficiency of phase - to - phase mixing and mass transfer, depends on the flow rate of the gas flowing through the Venturi. High efficiency is only obtained with high flow rates and thus high pressure losses. Therefore, the fluid motive force needs to be applied to the gas phase via a gas pumping mechanism such as a fan or blower. The second configuration, generally called a Venturi - ejector scrubber, uses a high - pressure / high - velocity jet or spray of the liquid phase flow to provide the motive force for the combined fluid flow and turbulent mixing of the phases. A useful side effect is that since the gas phase is effectively pumped through the Venturi, there is no need to use a fan or blower.This is particularly advantageous when the gas phase is at a high temperature or is highly chemically reactive. The configuration of the Venturi-ejector has been found to be able to simultaneously solve three problems: powder discharge, scrubbing of water-soluble gas, and pressure loss of the system, and has been selected as part of the decontamination system for development by the present inventors. An essential part of any configuration of the Venturi-scrubber system is the need to separate the multiphase mixture after the Venturi. The liquid phase (which may be referred to herein as entrained liquid, scrubber liquid, or scrubber water) can be discarded or reused. Conventionally, both of the above configurations have been arranged such that the fluid flows by gravity. The exhaust from the scrubber is discharged into a gas-liquid separator. This gas-liquid separator is generally in the form of a tank that allows for gravitational sedimentation of large droplets. Generally, the gas-phase exhaust stream from the tank contains smaller droplet mists, which then pass through a final stage such as a cyclone separator and a swirl separation column. This design leads to a large installation area and cost associated with additional downstream separators. A compact design of the gas-liquid separator and the Venturi-ejector scrubber was envisioned for integrating the decontamination system in locations with limited installation space. In the initial design of the separator section, emphasis was placed on implementing multiple cyclone separators in parallel. However, the high liquid / gas ratio (>1 liter of liquid / m3 of gas) employed in the Venturi ejector scrubber places a burden on the cyclones, resulting in unacceptable pressure losses and an unstable flow with the influence of excessive liquid (droplets).

[0005] Accordingly, generally provided is a separator for separating contaminants or particulates floating in a combustion exhaust gas stream or an exhaust stream. The separator can include an inlet conduit configured to receive an exhaust stream containing contaminants flowing in a first main direction from a decontamination device. The separator can include a spray nozzle configured to spray a carrier fluid into the inlet conduit in the first main direction to entrain or capture contaminants in the exhaust stream. The first main direction can be a direction from the lower part to the upper part of the separator. The separator can include a first flow direction conversion structure positioned or located downstream of the inlet conduit. The separator can include a first separation conduit positioned or located downstream of the first flow direction conversion structure. The first flow direction conversion structure can be configured to divert the flow of the exhaust stream and the carrier fluid to a second main direction opposite to the first main direction in the first separation conduit. The first flow direction conversion structure can divert the flow of the exhaust stream and the carrier fluid from an axial flow to a circumferential flow. The circumferential flow can carry the exhaust stream and the carrier fluid having a circumferential component in the second main direction. Thus, by changing the direction of the flow, a longer flow path can be created while minimizing the installation area and dimensions of the separator, thereby promoting the separation of contaminants entrained by the carrier fluid from the exhaust stream. Also, this can provide a separator that exhausts an effluent containing less carrier fluid than a conventional venturi-ejector scrubber. Thereby, the need for additional downstream devices such as a cyclone separator that increases the cost and size of the apparatus can be eliminated.

[0006] The contaminants in the exhaust stream include suspended particulates or powders and, in some cases, unwanted acidic gases. The main direction is typically the direction of the major, net, or overall fluid flow. The separation conduit is generally a conduit in which separation of the carrier fluid from the exhaust stream can occur. Other processes may also occur in the separation conduit. The carrier fluid separated from the exhaust gas can be water.

[0007] The inlet conduit can expand in a first main direction towards the first flow direction conversion structure. The inlet conduit can include a constricted portion, an enlarged portion, and a necked portion between the Venturi tubes. The inlet conduit can have an inlet for receiving the discharge flow at the base or lower part of the separator and an outlet at the upper part or top of the separator. The first main direction can be a direction from the base or lower part of the separator towards the top or upper part of the separator.

[0008] The first flow direction conversion structure can be positioned between the inlet conduit and the first separation conduit.

[0009] The first flow direction conversion structure can be configured to convert the axial flow from the inlet conduit into a circumferential flow within the first separation conduit.

[0010] The separator can include a second flow direction conversion structure positioned downstream of the first separation conduit and a second separation conduit positioned downstream of the second flow direction conversion structure. The second flow direction conversion structure can be configured to convert the flow of the discharge flow and the entrained fluid into the first main direction opposite to the second main direction within the second separation conduit. Thus, it is possible to create a further change in the main flow direction that helps to further lengthen the flow path while minimizing the installation area and dimensions of the separator. The second flow direction conversion structure and the second separation conduit provide a further length to the flow path and enable the occurrence of further separation. The conditions of the first separation conduit and the second separation conduit may be different in order to improve the overall separation. For example, the discharge flow can change from high speed to low speed and / or from a rotational flow to a linear flow.

[0011] The second flow direction conversion structure can be positioned between the first separation conduit and the second separation conduit.

[0012] The second flow direction conversion structure can be configured to convert the circumferential flow from the first separation conduit into an axial flow within the second separation conduit.

[0013] The first separation conduit and / or the second separation conduit can coaxially surround the inlet conduit.

[0014] The first separation conduit and the second separation conduit can comprise nested annular tubes that coaxially surround the inlet conduit. The second separation conduit can be positioned radially between the first separation conduit and the inlet conduit. The first separation conduit can be positioned radially between the second separation conduit and the inlet conduit. These coaxial configurations can provide a compact separator. The first separation tube can be formed between or defined by an outer annular housing and an intermediate annular housing, and the second separation conduit can be defined by the intermediate annular housing and an inner annular housing structure. This provides a nested structure in which one conduit feeds another positioned coaxially, and the direction of the flow path through each conduit alternates.

[0015] At least one of the first flow direction changing structure and the second flow direction changing structure can be configured to present a curved surface or a contoured surface to the discharge flow and the entrained fluid flow to redirect the discharge flow and the entrained fluid flow. The curved surface can facilitate the redirection of the discharge-entrained fluid mixture and can provide a component of rotational flow in some arrangements. The rotational flow can be a circumferential flow around the first separation conduit. The curved surface of the first flow direction changing structure can be provided by a curved conical structure. This can provide a uniform distribution of the discharge-entrained fluid mixture to the first separation conduit and can improve the separation efficiency.

[0016] The first flow direction changing structure can comprise a first radial element or lobe extending between the inlet conduit and the first separation conduit.

[0017] The first radial element can be circumferentially positioned around the inlet conduit. In addition to a cone, the first radial element can act to guide the flow through the direction changing structure.

[0018] The inlet conduit can define a longitudinal axis. The first radial element can be configured to impart a rotational or circumferential flow around the longitudinal axis to the exhaust flow and entrained fluid within the first separation conduit. By inducing a rotational or circumferential flow, a helical structure or helical fluid flow path can be formed within the first separation conduit in a second main direction. The rotational flow can significantly increase the path length of the exhaust flow and thus provide a greater opportunity for separation. Further, due to the centrifugal effect, heavier entrained liquid can be pushed radially outward of the first separation conduit and thus separated from the lighter exhaust gas. This is a similar effect achieved in a cyclone separator. Advantageously, however, in this arrangement, no moving / rotating element is required to cause centrifugal force.

[0019] The rotational flow can include a circumferential flow around the first separation conduit.

[0020] The first radial element can be shaped to present a curved surface to the exhaust flow and entrained fluid in order to impart a rotational flow. In other words, the first radial element can present a non-linear surface that changes direction generally from a radial direction to a circumferential direction in order to impart a rotational or circumferential flow.

[0021] The first radial element can include a claw-shaped or curved teardrop-shaped cross-section.

[0022] Adjacent first radial elements can define at least partially curved flow paths in order to impart a rotational flow.

[0023] The first radial element can define an exhaust conduit that is fluidly coupled to the second separation conduit and is configured to convey the exhaust flow from the second separation conduit to an exhaust port. The exhaust port can be connected to a downstream device, such as a packed bed scrubber. The exhaust conduit can be oriented to convey the exhaust flow to the exhaust port in a first main direction. The exhaust conduit can be positioned at the top of the separator.

[0024] The second flow direction conversion structure can include a second radial element extending between the first separation conduit and the second separation conduit.

[0025] The second radial element can be circumferentially positioned around the first separation conduit and the second separation conduit.

[0026] The second radial element is configured to suppress or limit the rotational flow of the discharge flow and entrained fluid within the first separation conduit and the second separation conduit.

[0027] The second radial element can be shaped to present a plane to the discharge flow and entrained fluid to suppress the rotational flow. In other words, the second radial element can present a linear surface that imparts a linear flow.

[0028] Adjacent second radial elements can at least partially define a radial flow path for suppressing the rotational flow.

[0029] The second radial element can include a flat plate or baffle. The second radial element can slow the flow of the entrained fluid and discharge, thereby promoting separation. Further, the second radial element can suppress the rotational flow caused upstream by the first direction conversion structure. This allows for a substantially laminar and / or linear flow at low speed through the second separation conduit, and the exhaust of the separator is such that turbulent flow is suppressed.

[0030] The second flow direction conversion structure can define at least one outlet, drain port, or discharge hole positioned or configured to discharge the accumulated entrained fluid to a drain sump.

[0031] The separator can be provided with at least one other drain, exhaust duct or outlet configured to discharge liquid deposited downstream of the separator's exhaust port and exhaust duct into a drain sump. The at least one drain is configured to maintain separation between the liquid discharged within the inlet duct, first flow direction conversion structure, first separation duct, second flow direction conversion structure, second separation duct, and exhaust duct, the entrained fluid and the discharge flow, and is adapted to prevent re-entrainment. The drain can provide a drainage path to the drain sump for any entrained fluid or liquid contaminants remaining in the discharge flow after passing through the separator and before flowing into a downstream device. Thereby, the liquid from the exhaust duct at the upper part of the separator can be conveyed to the drain sump at the lower part of the separator.

[0032] The at least one drain can extend through the first flow direction conversion structure, the first radial element, and the second separator duct. This arrangement provides a discharge flow path that does not increase the installation area or height of the separator.

[0033] The second separation duct can be dimensioned such that the average flow velocity within the second separation duct is less than 6 m / s, preferably less than 3 m / s. Such a low velocity can facilitate the separation of the entrained fluid and contaminants from the discharge flow. The second radial element of the second flow direction conversion structure can help achieve this flow velocity, but the size of the second separation duct can determine the flow velocity therethrough. Larger ducts provide slower flow, while smaller ducts can provide faster flow. It should be noted that the dimensions of the entire separator need to be selected such that there is sufficient pressure within the exhaust duct to discharge the discharge flow.

[0034] The first main direction can be substantially vertically upward (opposite to the direction of gravity), and the second main direction can be substantially vertically downward (in the same direction as gravity). As described above, conventional venturi-ejector scrubbers spray the entrained fluid downward. The inventors have recognized that by doing the opposite, an obscure path can be created to change the direction without adversely affecting the venturi-ejector scrubber.

[0035] In an embodiment, the entrained fluid is one of water, an alkaline solution, and an acid solution. An alkaline compound, such as lime (CaO), can provide an enhanced acid scrubbing or desulfurization process. The acid solution can enhance the capture of alkaline gases such as ammonia.

[0036] A second aspect provides a method of separating contaminants from an exhaust stream using a separator, the method comprising receiving the exhaust stream in a first main direction at an inlet conduit of the separator; spraying an entrained fluid into the inlet conduit in the first main direction to entrain contaminants; using a first flow direction changing structure positioned downstream of the inlet conduit to redirect the flow of the entrained fluid and the exhaust stream to a second main direction opposite the first main direction; and separating the entrained fluid containing contaminants from the exhaust stream using a first separation conduit.

[0037] The method can include steps corresponding to the steps performed by the features of the first aspect as described above.

[0038] Further specific and preferred aspects are described in the appended independent and dependent claims. The features of the dependent claims may, where appropriate, be combined with the features of the independent claims, and may also be combined in combinations other than those explicitly described in the claims.

[0039] If a feature of an apparatus is described as being operable to provide a certain function, this will be understood to include features of an apparatus that provide, or are adapted or configured to provide, that function.

[0040] Next, embodiments of the present invention will be further described with reference to the accompanying drawings.

Brief Description of the Drawings

[0041]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Modes for Carrying Out the Invention

[0042] Before describing the embodiments in more detail, an overview is first presented. Some embodiments provide a separator for separating contaminants, such as particulate matter in a combustion exhaust gas stream or a process exhaust stream, using a carrier fluid. The separator is configured to redirect a flow of a process exhaust stream and a carrier fluid moving in a first main direction to a second main direction opposite to the first main direction. This increases the length of the flow within the separator, increases the residence time, and while keeping the separator compact, increases the likelihood that the carrier fluid captures and separates the contaminants. The separator can further return the flow of the process exhaust stream and the carrier fluid (a mixture of the exhaust and the carrier fluid) in the second separator conduit in the first main direction opposite to the second main direction. This further increases the length of the flow within the separator, increases the residence time, and while keeping the separator compact, increases the likelihood that the carrier fluid captures and separates the contaminants.

[0043] Existing venturi-ejector scrubbers spray the carrier fluid in a downward direction. The carrier fluid is collected in a drain sump at the bottom of the scrubber, and the exhaust gas can exit through an outlet above the drain sump. However, such an arrangement can result in a large installation area. Further, the water droplets of the carrier fluid are often carried through the outlet by the exhaust stream, leading to the need for additional devices such as a cyclone separator downstream of the scrubber that further increases size, cost, and complexity. In contrast, in some embodiments, the first main direction can be an upward direction and the second main direction can be a downward direction.

[0044] Accordingly, some embodiments are directed to a novel venturi-ejector scrubber combined with a gas (e.g., exhaust)-liquid (e.g., entrained fluid) separator that solves at least one of the above problems. Primarily, some embodiments promote improved separation while minimizing the size of the separator by redirecting the exhaust-entrained fluid mixture one or more times. If the first redirection provides a swirling flow that results in a kind of centrifuge, the separation can be further improved. Also, increasing the path length can improve the separation. The separation of water droplets can be further caused by, for example, a low-speed section of less than 6 m / s, preferably less than 3 m / s. Some embodiments are directed to providing these different conditions that result in separation. In some cases, different contaminants tend to separate under different conditions. The first and second flow turning structures and the first and second separation conduits can be appropriately shaped and sized to provide the conditions that result in separation.

[0045] Figures 1-6 show an embodiment of a separator 2, also referred to herein as a combined venturi-ejector scrubber and gas-liquid separator, comprising an inlet 3, an inlet conduit 6, a first flow turning structure 7, a first separation conduit 31, a second flow turning structure 33, a second separation conduit 32, and an exhaust conduit 16.

[0046] The inlet 3 disposed at the lower part of the separator 2 is configured to receive an exhaust stream 1 containing contaminants such as fine particles. The inlet 3 is connected to an inlet conduit 6, also referred to herein as a venturi tube, which is defined by an inner tube or housing 30. The inlet conduit 6 defines a longitudinal axis. The first main direction is defined by the exhaust flow in the inlet conduit 6 along its longitudinal axis, generally upward. The inlet conduit 6 can be formed from two tapered portions (a first narrowing portion followed by an expanding portion) to form a venturi tube.

[0047] The high-speed spray 4 is discharged into the constricted portion of the inlet conduit 6 defined between two tapered portions. The hydraulic spray nozzle 5 associated with the spray 4 is configured to spray the entraining fluid into the inlet conduit 6 along a first main direction in order to entrain contaminants within the discharge stream 1. The entraining fluid can be a high-pressure hydraulic spray water spray.

[0048] Downstream of the inlet conduit 6, a first flow reversal structure or flow direction changing structure 7 is configured to redirect the effluent-entraining fluid mixture (sometimes referred to as the discharge stream) in a second main direction different from the first main direction. The second main direction is opposite to the first main direction and can be parallel to the longitudinal axis. The first flow direction changing structure 7 includes an axially attached conical portion, or cone 8, and a plurality of first radial elements 9, sometimes referred to as flow direction changing elements. The cone 8 is attached with its pointed side down and presents a surface curved towards the effluent-entraining fluid mixture. The cone 8 can include a vortex-like shape.

[0049] Figures 2 and 3 show that the first radial elements 9 are circumferentially positioned around the longitudinal axis and include claw-like elements having curved surfaces. Adjacent first radial elements 9 define a flow path through which the effluent-entraining fluid mixture is directed. It should be understood that while the flow path is preferably curved, other shapes that are not necessarily curved are suitable for the first radial elements 9 that direct the effluent-entraining fluid mixture.

[0050] The cone 8 and the first radial elements 9 are configured to redirect the effluent-entraining fluid mixture into a first separation conduit 31 defined between an outer tube or housing 10 and an intermediate tube or housing 13 (sometimes referred to herein as an inner flow guide). The first separation conduit 31 is coaxial with the inlet conduit 6 and is positioned around the inlet conduit 6, and the first separation conduit 31 is configured to form an annular passageway.

[0051] The conical body 8 and the curved surface of the first radial element 9 of the first flow direction conversion structure 7 are configured to impart a rotational flow or a circumferential flow to the discharge-carried fluid mixture, and the discharge is adapted to pass through the first separation conduit 31 in a spiral or helical flow path.

[0052] The separator 2 further comprises a second flow direction conversion structure 33 positioned downstream of the first separation conduit 31. The second flow direction conversion structure 33 is configured to redirect the flow of the discharge-carried fluid mixture from the second main direction towards the first main direction for a flow direction change. The second flow direction conversion structure 33 can further comprise a second radial element 14 configured to block the rotational flow of the discharge-carried fluid mixture and thus stop the rotational flow from the first separation conduit and restore a linear flow. The second radial element 14 comprises a baffle or a flat plate. This plate extends between the outer surface of the inner housing 30 and the inner surface of the outer housing 10.

[0053] The second flow direction conversion structure 33 can further comprise at least one drain hole or outlet 11. The outlet 11 enables water to flow out into a drain sump 12 positioned below the separator 2. The drain sump 12 can be formed integrally with or independently of the separator 2.

[0054] The second separation conduit 32 positioned downstream of the second flow direction conversion structure 33 is configured to provide a flow path for the discharge-carried fluid mixture in the second main direction towards the exhaust conduit 16.

[0055] The second separation conduit 32 is positioned coaxially and radially between the inlet conduit 6 and the first separation conduit 31. The second separation conduit 32 is defined between the inner housing 30 and the intermediate housing 13 so as to form an annular passage. The first and second flow direction conversion structures 7, 33 are positioned at the axial ends of the nested coaxial tubes forming the inlet conduit 6, the first separation conduit 31, and the second separation conduit 32.

[0056] Downstream of the second separation conduit 32, the exhaust conduit 16 comprises a plurality of gas pipes circumferentially positioned around the downstream end of the second separation conduit 32. The gas pipes pass through the first flow direction conversion structure 7 and, in particular, extend through the first radial element 9. The gas pipes fluidly couple the second separation conduit 32 to the exhaust port at the top of the separator 2. It should be understood that the exhaust conduit 16 can comprise a different number of gas pipes than those depicted in this embodiment. For example, the exhaust conduit 16 can comprise one or two or more gas pipes. The exhaust conduit 16 can comprise the same number of gas pipes as the number of first radial elements 9, but this is not essential.

[0057] Each gas pipe comprises a rising portion 19 extending above the first flow direction conversion structure 7 to prevent the liquid accumulated at the top of the separator 2 from flowing back through the exhaust port and "re-entraining". To discharge the accumulated fluid without the risk of re-entrainment, the separator 2 comprises a drain or discharge flow path 20 extending through the first flow direction conversion structure 7 and, in particular, through the first radial element 9. The drain flow path 20 is configured such that scrubber water or other accumulated liquid is discharged into the collection drain sump 12 without mixing with the effluent passing through the separator 2. The drain flow path 20 is circumferentially radially outwardly positioned from the gas pipes of the exhaust conduit 16 and extends through the first flow direction conversion structure 7 towards the lower drain sump 12. It should be understood that the drain flow path 20 can comprise one or two or more drain flow paths.

[0058] FIG. 7 shows an embodiment in which a packed bed wet scrubber 17 follows the separator 2 to enhance the gas scrubbing performance. FIG. 7 shows the support plate 18 for the scrubber packing (the scrubber packing is not included for clarity). A feature of this embodiment is the short rising portion 19 at the outlet of the gas pipe 16, which enables the scrubber water to be collected and discharged through the flow path 20 into the liquid collection drain sump 12 without coming into significant contact with the gas flow 21. This prevents re-entrainment of the droplets back into the gas flow.

[0059] To maximize the efficiency of the packed bed scrubber, it is effective to ensure that the gas flow entering the bottom of the packed tower is distributed as uniformly as possible. For this purpose, numerical fluid dynamics (CFD) flow modeling of the flow exiting the gas-liquid separator enabled the optimization of the hole size and distribution of the support plate 18 of the scrubber packing. To optimize the configuration of the support plate, it is necessary to reduce the hole size and density of the direct line of sight of the exhaust port / riser 19 of the gas-liquid separator of the exhaust duct to forcibly disperse the gas flow.

[0060] During use, the gas-particle flow (exhaust) stream 1 enters the separator 2 at the bottom of the separator 2 and moves vertically upward through the inlet 3 on the lower surface of the separator 2. Here, the stream 1 contacts and mixes with the high-speed spray 4 (shown as a cone in Figure 1) supplied via the hydraulic spray nozzle 5 as it passes through the venturi inlet duct 6. The stream 1 further rises and finally exits the venturi inlet duct 6 and enters the flow reversal part of the device. Note that in the following description, the sprayed entrained fluid can be referred to as water.

[0061] The exhaust stream 1 is drawn into the separator 2 by the suction action caused by spraying water in the first main direction and being pressurized by the upstream exhaust. In this way, the exhaust containing contaminants is pushed through the inlet duct 6 and combined with the atomized water droplets. Since the water droplets are usually of the same size as the contaminants, the acid gas particles and small powders in the exhaust stream 1 easily adhere to or are absorbed by the sprayed water.

[0062] By using a high-pressure spray, the separator 2 can have a longer flow path. In the case of a low-pressure water spray, the pressure or energy decreases, and without additional assistance such as an external fan, the ability to discharge the exhaust by reversing the direction one or more times from the separator decreases. The preferred velocity of the water passing through the inlet duct 6 is 50 - 150 m / s. At these velocities, it is not important that the spray is carried out upward.

[0063] After exiting the Venturi inlet conduit 6, the effluent - entrained fluid mixture contacts the axially mounted cone 8 which divides the flow and directs it (radially) outwardly towards the flow guiding element 9 which imparts a tangential (rotational) and downward direction to the flow. The effluent - entrained fluid mixture, upon exiting the flow reversal section 7, is directed towards the inner surface of the outer housing 10. Upon impact with the inner surface of the outer housing 10, the momentum of the denser liquid portion of the flow separates the liquid portion from the gas portion. The liquid forms a film on the inner surface of the outer housing 10 and, under the influence of gravity, falls towards the bottom of the separator 2.

[0064] Rotational / tangential / circumferential flow is preferred over straight - line flow because the travel distance of the effluent - entrained fluid mixture is increased and thus the time until separation occurs is increased. Further, the rotational motion provides a centrifugal effect which aids in the separation of the contaminated water from the gas effluent. It should be noted that the effluent - entrained fluid mixture follows a substantially helical path within the first separation conduit 31 and the net flow is downward (the second major direction).

[0065] Through the hole 11 at the bottom of the separator 2, the liquid is discharged to the drain sump 12. The drain sump 12 collects the entrained fluid (scrubber liquid) which is then recycled through the system or pumped to the waste stream.

[0066] The effluent - entrained fluid mixture, in which the liquid portion has significantly decreased but still remains, continues to swirl around the outer annular chamber 31 of the gas - liquid separator while transporting droplets. This flow, due to the presence of the inner flow guide 13, is directed downward towards the baffle 14, similar to the tangential / rotational direction. According to CFD simulations, the peak velocity of the fluid as it passes between the flow guiding elements exceeds 15 m / s, but is less than 6 m / s by the time the fluid contacts the baffle, and further decelerates. The remaining water droplets settle under gravity and are discharged into the drain sump 12. The baffle helps to change the circumferential flow into a more linear flow. The remaining flow with few droplets at this point rises through the inner annular chamber 15 of the gas - liquid separator 2 and passes through the arrangement of the gas pipes 16. The dimensions of the inner annular chamber 15 are selected such that the typical flow velocity immediately becomes less than 3 m / s, and thus only very small droplets can be transported. Preferably, the effluent moves through the second separation conduit 32 at the lowest possible speed, thus providing the maximum opportunity for contaminants to be separated. The separated water can fall to the bottom of the second flow - direction - changing structure, where it flows out through the drain hole 11 into the drain sump 12.

[0067] In an alternative embodiment, the second separation conduit 32 can be positioned radially outside the first separation conduit 31, which is positioned radially outside the inlet conduit 6. In this way, a zig - zag type flow path can be formed. This arrangement can provide an alternative low - cost separator since the exhaust conduit and the drain flow path may not need to pass through the first flow - direction - changing structure.

[0068] Exemplary embodiments of the present invention have been disclosed herein in detail with reference to the accompanying drawings, but the present invention is not limited to the exact embodiments, and it is understood that various changes and modifications can be made by those skilled in the art without departing from the scope of the present invention as defined by the appended claims and their equivalents.

Description of the Reference Numerals

[0069] 1 Discharge flow 2 Separator 3 Inlet 4 Spray 5 Spray nozzle 6 Inlet conduit 7 First flow direction conversion structure 8 Cone 9 First radial element 10 Outer housing 11 Outlet 12 Drainage tank 13 Intermediate housing 14 Second radial element 16 Exhaust conduit 17 Packed bed wet scrubber 18 Support plate 19 Upright portion 20 Discharge channel 21 Exhaust gas flow 30 Inner pipe / Inner housing 31 First separation conduit 32 Second separation conduit

Claims

1. A separator for separating contaminants in an exhaust stream, comprising: an inlet conduit configured to receive the exhaust stream containing contaminants from a decontamination device and flowing in a first main direction from the lower part to the upper part of the separator; a spray nozzle configured to spray a carrier fluid into the inlet conduit in the first main direction to entrain the contaminants in the exhaust stream; a first flow direction conversion structure positioned downstream of the inlet conduit; a first separation conduit positioned downstream of the first flow direction conversion structure; wherein the first flow direction conversion structure is configured to convert the flow of the exhaust stream and the carrier fluid from an axial flow from the inlet conduit to a circumferential flow in a second main direction opposite to the first main direction in the first separation conduit, the separator.

2. The separator according to claim 1, wherein the inlet conduit expands in the first main direction towards the first flow direction conversion structure.

3. The separator according to claim 1 or 2, wherein the first flow direction conversion structure is positioned between the inlet conduit and the first separation conduit.

4. The separator according to any one of claims 1 to 3, further comprising a second flow direction conversion structure positioned downstream of the first separation conduit and a second separation conduit positioned downstream of the second flow direction conversion structure, wherein the second flow direction conversion structure is configured to convert the flow of the exhaust stream and the carrier fluid to the first main direction opposite to the second main direction in the second separation conduit.

5. The separator according to claim 4, wherein the second flow direction conversion structure is positioned between the first separation conduit and the second separation conduit.

6. The separator according to claim 4 or 5, wherein the first separation conduit and the second separation conduit coaxially surround the inlet conduit.

7. The separator according to any one of claims 1 to 6, wherein at least one of the first flow direction conversion structure and the second flow direction conversion structure is configured to present a curved surface to the exhaust stream and the carrier fluid to convert the flow thereof.

8. The separator according to any one of claims 1 to 7, wherein the first flow direction conversion structure comprises a first radial element extending between the inlet conduit and the first separation conduit.

9. The separator according to claim 8, wherein the first radial element is circumferentially positioned around the inlet conduit.

10. The separator according to claim 8 or 9, wherein the inlet conduit defines a longitudinal axis, and the first radial element is configured to impart a rotational flow around the longitudinal axis to the discharge flow and the entrained fluid within the first separation conduit.

11. The separator according to any one of claims 8 to 10, wherein the first radial element is shaped to present a curved surface to the discharge flow and the entrained fluid in order to impart the rotational flow.

12. The separator according to any one of claims 8 to 11 when dependent on any one of claims 4 to 7, wherein the first radial element defines an exhaust conduit fluidly coupled to the second separation conduit and is configured to convey the discharge flow from the second separation conduit to an exhaust port.

13. The separator according to any one of claims 4 to 12, wherein the second flow direction changing structure comprises a second radial element extending between the first separation conduit and the second separation conduit.

14. The separator according to claim 13, wherein the second radial element is circumferentially positioned around the first separation conduit and the second separation conduit.

15. The separator according to claim 13 or claim 14, wherein the second radial element is configured to suppress the rotational flow of the discharge flow and the entrained fluid within the first separation conduit and the second separation conduit.

16. A method of separating contaminants from a discharge flow using a separator, comprising: receiving the discharge flow in a first main direction from a lower part to an upper part of the separator at an inlet conduit of the separator; spraying an entrained fluid into the inlet conduit in the first main direction to entrain the contaminants; using a first flow direction changing structure positioned downstream of the inlet conduit to divert the flow of the entrained fluid and the discharge flow from an axial flow from the inlet conduit to a circumferential flow in a second main direction opposite to the first main direction; ​ ​ Separating the entrained fluid containing the contaminant from the effluent stream using a first separation conduit; A method comprising.

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