TECHNICAL FIELD
The present disclosure relates to the field of refining of crude oil. More specifically, the present disclosure relates to a de-foaming cyclonic device for separation of foam or gas from crude oil in a pre-flash drum.
BACKGROUND
Generally, pre-flash drums are used in refineries for the refining process of crude oil. It is commonly known, that a pre-flash drum is a vessel to separate/flash-off the lighter crude components and vapours generated due to preheating of the crude oil in preheat exchanger. The pre-flash drum primarily removes light boiling range hydro-carbons and reduces the water carryover that can cause corrosion in the devices or vaporization in the control valves. During the heating of the crude oil in the preheat exchanger, the temperature of crude oil is high while the pressure is low. Consequently, foam is produced in the pre-flash drum when pressure is further reduced across an upstream control valve. At this stage, if foam is contained inside the pre-flash drum, it causes problems like difficulty in level measurement and cavitation. Further, if the foam is carried to the distillation columns, it hampers diesel production.
With on-going efforts in industry, various foam separators have been employed in crude oil refineries. One such foam separator is a gas-liquid cyclone (GLC) separator to separate two phases (liquid-vapor or Crude-foam) effectively with minimum pressure drop for a pre-flash drum feed in refineries. However, one major drawback of GLC separators is the need of having large size pre-flash drum to accommodate the GLC separators making the arrangement heavy and uneconomic. Also, the existing GLC separators have vortex tails (liquid outlet end of the GLC) immersed in liquid, this requires huge investment for supporting structures and additional ducts for maintaining immersion liquid level.
In other words, researchers are constantly working to develop a more efficient and technically advance de-foaming device for pre-flash drums in refineries. More specifically, there exists a need for an economical de-foaming device that provides effective de-foaming of large volumes of crude oil in pre-flash drum to mitigate one or more limitations stated above.
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SUMMARY
Embodiments of the present disclosure provides a de-foaming cyclonic device comprising a distributor channel and a plurality of cyclonic devices. The distributor channel has an internal surface defining a passage for receiving a foamed liquid through an upper end and the plurality of cyclonic devices are disposed around an outer circumference of a lower end of the distributor channel. Each of the plurality of cyclonic devices comprises, a cylindrical chamber, an inlet channel, an inverted conical chamber, and an outlet channel. The cylindrical chamber comprising a longitudinal cavity having a predefined height (H1) and a cavity diameter (D1), wherein the height (H1) is 1.25 to 1.3 times the cavity diameter (D1). The inlet channel is formed in a side portion of said cylindrical chamber for receiving the foamed liquid from the distributor channel, said inlet channel has a predefined inlet width (W2) and inlet height (H2). Wherein, the inlet width (W2) is 0.1 to 0.4 times the cavity diameter (D1) and inlet height (H2) is 0.1 to 0.4 times the cavity diameter (D1). The inverted conical chamber is formed in a lower portion of said cylindrical chamber for discharging liquid, said inverted conical chamber has a predefined liquid discharge outlet diameter (D3) and outlet height (H3). Wherein, the outlet diameter (D3) is 0.25 to 0.5 times the cavity diameter (D1) and outlet height (H3) is 2.5 to 3 times the cavity diameter (D1). The outlet channel is co-axially mounted to an upper portion of said cylindrical chamber and connected thereto to expel foam or gas separated from foamed liquid. The outlet channel has a predefined discharge diameter (D4), wherein the discharge diameter (D4) is 0.25 to 0.5 times the diameter (D1).
In an embodiment, the inlet channel extends through the side portion of the cylindrical chamber for tangentially introducing the foamed liquid into the cylindrical chamber and to induce a centrifugal downward flow to the foamed liquid within the cylindrical chamber.
In an embodiment, the inlet channel is substantially a tapered wedge shape having small cross-sectional flow area at the inlet.
In an embodiment, the inverted conical channel is substantially a frusto-conical wall section having a base portion connected to the lower portion of the cylindrical chamber and an apex portion having a liquid discharge outlet.
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In an embodiment, the outlet channel defines a tubular internal surface having a receiving end extending vertically downward into said cylindrical chamber and a discharge opening extending outwardly therefrom above the upper portion of said cylindrical chamber.
In an embodiment, the receiving end of outlet channel has a predefined depth (C4) measured from the upper portion of said cylindrical chamber, said predefined depth of receiving end (C4) is 0 to 1.3 times the cavity diameter (D1).
In an embodiment, the said inlet channel has a predefined center distance (C2) measured from the upper portion of said cylindrical chamber, said center distance (C2) is 0.05 to 1.15 times of the cavity diameter (D1)
The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The novel features and characteristic of the disclosure are set forth in the appended claims. The disclosure itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying figures. One or more embodiments are now described, by way of example only, with reference to the accompanying figures wherein like reference numerals represent like elements and in which:
Figure 1. depicts a de-foaming cyclonic device according to an embodiment of the present disclosure; and
Figure 2. depicts a cyclonic device according to an embodiment of the present disclosure.
The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
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DETAILED DESCRIPTION
While the invention is subject to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the figures and will be described below. It should be understood, however that it is not intended to limit the invention to the particular forms disclosed, but on the contrary, the invention is to cover all modifications, equivalents, and alternative falling within the scope of the invention.
Before describing in detail embodiments, it may be observed that the novelty and inventive step that are in accordance with the present disclosure recites a de-foaming cyclonic device. It is to be noted that a person skilled in the art can be motivated from the present invention and modify the various constructions of assembly, which are varying based on application. However, such modification should be construed within the scope and spirit of the invention. Accordingly, the drawings are showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having benefit of the description herein.
The terms “comprises”, “comprising”, or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a setup, device that comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such setup or device. In other words, one or more elements in a system or apparatus preceded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or apparatus.
Accordingly, it is an aim of the present disclosure to provide an efficient and technically advanced de-foaming cyclonic device for pre-flash drums in crude oil refineries
Embodiments of the present disclosure are related to a de-foaming cyclonic device 100 for a pre-flash drum or flash vessel. The de-foaming cyclonic device 100 is at least partially disposed within the pre-flash drum to treat a foamed liquid, such as flashed crude oil product, for prevention or separation or reduction of foam or gas. Now referring to figure 1, the de-foaming cyclonic device 100 [interchangeably referred as dFCD hereinafter] comprises a distributor channel 10 and a plurality of cyclonic devices 20. The distributor channel 10 is substantially a
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tube defining a passage for receiving and distributing the foamed liquid. The distributor channel 10 has an upper end and a lower end. The upper end is connected to the pre-flash drum (not shown in the figures) and functions as a means for receiving the foamed liquid feed. Whereas the lower end functions as a means for even distribution of foamed liquid to the plurality of cyclonic devices 20 disposed around an outer circumference of lower end of the distributor channel 10.
Now referring to figure 2, each of the plurality of cyclonic devices 20 comprises a cylindrical chamber 1, an inlet channel 2, an inverted conical channel 3 and an outlet channel 4. The cylindrical chamber 1 is substantially a cylindrical wall section having a longitudinal cavity of predefined height (H1) and cavity diameter (D1). The height (H1) is preferably 1.25 to 1.3 times the cavity diameter (D1). The inlet channel 2 is tangentially formed, and may selectively close, about an upper portion of cylindrical chamber 1. The inlet channel extends through a side portion of the cylindrical channel, for tangential introduction of the foamed liquid into the cylindrical chamber 1 and to induce a centrifugal downward force to the foamed liquid with the cylindrical chamber 1. The inlet channel 2 is substantially a tapered wedge shape having small cross-sectional flow area at a receiving end for foamed liquid. The receiving end having a predetermined inlet width (W2) and inlet height (H2). Inlet width (W2) is measured in perpendicularly to axis of cylindrical chamber 1, whereas the inlet height (H2) is measured about along the axis of cylindrical chamber 1. Further, the inlet channel is having a predefined centre distance (C2) measured from the upper portion of said cylindrical chamber to the centre of inlet height (H2). Preferably, the inlet width (W2) is 0.1 to 0.4 times the cavity diameter (D1), the inlet height (H2) is 0.1 to 0.4 times the cavity diameter (D1) and the centre distance (C2) is 0.05 to 1.15 times of the cavity diameter (D1).
The inverted conical channel 3 is coupled in a lower portion of the cylindrical chamber 1. The inverted conical channel 3 is substantially a frusto-conical wall section having a base portion connected to the lower portion of the cylindrical chamber and an apex portion having a liquid discharge outlet of predetermined outlet diameter (D3). Whereas, the height (H3) is the total height of inverted conical channel 3. Preferably, the outlet diameter (D3) is 0.25 to 0.5 times the cavity diameter (D1), whereas, the outlet height (H3) is 2.5 to 3 times the cavity diameter (D1). The cyclonic device 20 is further provided with the outlet channel 4 mounted co-axially to the upper portion of cylindrical chamber 1 for expelling foam or gas separated from foamed liquid. The outlet channel 4 defines a tube having internal surface for expelling foam or gas.
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The outlet channel 4 has a receiving end extending vertically downward into the cylindrical chamber 1 and a discharge opening extending outwardly therefrom above the upper portion of the cylindrical chamber 1. The internal surface of the outlet channel 4 has a predetermined discharge diameter (D4) and preferably, the discharge diameter (D4) is 0.25 to 0.5 time the cavity diameter (D1). Furthermore, the receiving end of outlet channel has a predefined depth (C4) measured from the upper portion of said cylindrical chamber. Preferably the depth of receiving end (C4) is 0 to 1.3 times the cavity diameter (D1).
In an embodiment, when foamed liquid enters the dFCD 100, the foamed liquid enters the plurality of cyclonic devices 20 via the distributor channel 10. The foamed liquid is tangentially introduced into the cylindrical chamber 1 of each of the cyclonic devices 20 through the inlet channel 2. The shape of the cylindrical chamber 1 and the inverted conical chamber 3 connected to the lower portion of cylindrical chamber 1 induces the foamed liquid to spin creating a vortex. Larger or more dense particles of foamed liquid i.e. liquid is forced outwards to the walls of the cylindrical chamber 1 and the inverted conical chamber 3. Subsequently, liquid falls down through the outlet of inverted conical chamber 3 due to force of gravity. Concurrently, lighter or less dense particles of foamed liquid, i.e. foam or gas, reverses course and passes outwardly through the outlet channel 4.
In an embodiment the dFCD 100 of the present disclosure achieves a gas separation efficiency of 92% to 97% and a liquid separation efficiency of 95% to 100% respectively at each of the cyclonic devices 20.
In an embodiment, the dFCD 100 provides an economical option/alternative for higher flow rates to enhance efficiency of separation of foam from crude, thereby obviating the need for large size pre-flash drums especially during revamp to overcome capacity constraints.
In an embodiment, the dFCD 100 overcome the restriction to maintain minimum liquid level in preflash drum for ensuring immersion of the bottom of cyclonic device, therefore eliminates huge investment for supporting structures and long duct for maintain immersion liquid level.
In an embodiment, the dFCD 100 provides facility to removing particulates (solids or fluids) from an air, gas or liquid stream, without the use of filters, through vortex separation.
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Reference Numerals:
Equivalents:
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or
Reference Number
Description
100
De-foaming cyclonic device
10
Distributor channel
20
Plurality of cyclonic devices
1
Cylindrical chamber
2
Inlet channel
3
Inverted conical chamber
4
Outlet channel
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group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.
Any discussion of documents, acts, materials, devices, articles and the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary.
While considerable emphasis has been placed herein on the particular features of this disclosure, it will be appreciated that various modifications can be made, and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other modifications in the nature of the disclosure or the preferred embodiments will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.

We claim:
1. A de-foaming cyclonic device comprising:
a distributor channel having an internal surface defining a passage for receiving a foamed liquid through an upper end; and
a plurality of cyclonic devices disposed around an outer circumference of a lower end of the distributor channel;
wherein, each of the plurality of cyclonic devices comprises:
a cylindrical chamber comprising a longitudinal cavity having a predefined height (H1) and a cavity diameter (D1); wherein the height (H1) is 1.25 to 1.3 times the cavity diameter (D1);
an inlet channel formed in a side portion of said cylindrical chamber for receiving the foamed liquid from the distributor channel; said inlet channel having a predefined inlet width (W2) and inlet height (H2); wherein the inlet width (W2) is 0.1 to 0.4 times the cavity diameter (D1) and the inlet height (H2) is 0.1 to 0.4 times the cavity diameter (D1);
an inverted conical chamber formed in a lower portion of said cylindrical chamber for discharging liquid; said inverted conical chamber having a predefined liquid discharge outlet diameter (D3) and outlet height (H3); wherein outlet diameter (D3) is 0.25 to 0.5 times the cavity diameter (D1) and outlet height (H3) is 2.5 to 3 times the cavity diameter (D1); and
an outlet channel co-axially mounted to an upper portion of said cylindrical chamber and connected thereto to expel foam or gas separated from foamed liquid; said outlet channel having a predefined discharge diameter (D4); wherein discharge diameter (D4) is 0.25 to 0.5 times the diameter (D1).
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2. The device as claimed in claim 1, wherein the inlet channel extends through the side portion of the cylindrical chamber for tangentially introducing the foamed liquid into the cylindrical chamber and to induce a centrifugal downward flow to the foamed liquid within the cylindrical chamber.
3. The device as claimed in claim 1, wherein the inlet channel is substantially tapered wedge shape having small cross-sectional flow area at the inlet.
4. The device as claimed in claim 1, wherein the inverted conical channel is substantially a frusto-conical wall section having a base portion connected to the lower portion of the cylindrical chamber and an apex portion having a liquid discharge outlet.
5. The device as claimed in claim 1, wherein the outlet channel defines a tubular internal surface having a receiving end extending vertically downward into said cylindrical chamber and a discharge opening extending outwardly therefrom above the upper portion of said cylindrical chamber.
6. The device as claimed in claim 1 and claim 5, wherein the receiving end of outlet has a predefined depth (C4) measured from the upper portion of said cylindrical chamber, said predefined depth of receiving end (C4) is 0 to 1.3 times the cavity diameter (D1).
7. The device as claimed in claim 1, wherein the said inlet channel has a predefined center distance (C2) measured from the upper portion of said cylindrical chamber, said center distance (C2) is 0.05 to 1.15 times of the cavity diameter (D1).