CLIAMS:1. A gas-solid separator comprising

• a housing having an operative top and an operative bottom, said housing comprising;

o an inlet aperture formed on said operative top of said housing, said inlet aperture configured to receive an inlet conduit having a first operative end and a second operative end, said inlet conduit configured to introduce a gas-solid mixture in said housing, said first operative end of said inlet conduit passes through said inlet aperture and extends out through said operative top of said housing, and said second operative end of said inlet conduit extends in an operative downward direction within said housing;
o a first outlet aperture formed on said operative top of said housing, said first outlet aperture facilitates the discharge of cleaned gas containing minute amounts of solid particles;
o a second outlet aperture formed on said operative bottom of said housing, said second outlet aperture facilitates the removal of solid particles collected in said housing;
o a first separator and a second separator disposed in said operative middle of said housing such that said first separator and said second separator are axially spaced from each other;

• at least one axial swirl cone cyclone supported by said first separator and said second separator, said at least one axial swirl cone cyclone comprising;

o a cyclone body having a cylindrical portion and a conical portion extending from said cylindrical portion, said cylindrical portion defining a swirl zone and said conical portion defining a vortex zone; and a feed inlet formed on an operative upper end of said swirl zone;
o a cleaned gas outlet disposed within said feed inlet such that said cleaned gas outlet defines an annular space between said feed inlet and said cleaned gas outlet;
o swirl imparters disposed in said annular space.

2. The gas-solid separator as claimed in claim 1, wherein said first separator and said second separator are disposed in said operative middle of said housing such that said first separator and said second separator define three zones in said housing;

• a cleaned gas collecting zone defined operatively above said first separator;
• a flue gas-solid common feed header zone defined operatively in between said first separator and said second separator; and
• a common catch zone defined operatively below said second separator.

3. The gas-solid separator as claimed in claim 2, wherein said second operative end of said inlet conduit is in fluid communication with said flue gas-solid common feed header zone, and said inlet conduit has a plurality of feed distributor openings formed on said inlet conduit near said second operative end of said inlet conduit to facilitate the introduction of said gas-solid mixture in said flue gas-solid common feed header zone of said housing.

4. The gas-solid separator as claimed in claim 1 or claim 2, wherein said at least one axial swirl cone cyclone is disposed in said flue gas-solid common feed header zone such that said feed inlet of said axial swirl cone cyclone is in fluid communication with said flue gas-solid common feed header zone, and said cleaned gas outlet is in fluid communication with said cleaned gas collecting zone.

5. An axial swirl cone cyclone comprising;

• a cyclone body having a cylindrical portion and a conical portion extending from said cylindrical portion, said cylindrical portion defines a swirl zone and said conical portion defines a vortex zone and a feed inlet formed on an operative upper end of said swirl zone;
• a cleaned gas outlet disposed within said feed inlet such that said cleaned gas outlet defines an annular space between said feed inlet and said cleaned gas outlet;
• swirl imparters disposed in said annular space.

6. The axial swirl cone cyclone as claimed in claim 5 or claim 2, wherein a deep leg is disposed at an operative bottom end of said vortex zone for collecting solid particles entrained in gas-solid mixture, and said deep leg is in fluid communication with said common catch zone.

7. A process for separation of solid particles from a gas-solid mixture, said process comprising the following steps:

• introducing the gas-solid mixture into a flue gas-solid common feed header zone of a gas-solid separator;
• providing a plurality of axial swirl cone cyclones disposed within said gas-solid separator, each of said axial swirl cone cyclone comprising a cleaned gas outlet conduit, a swirl zone having a feed inlet, swirl imparters, and a vortex zone, such that said swirl zone is in fluid communication with said flue gas-solid common feed header zone and said swirl zone is adapted to receive said gas-solid mixture;
• allowing said swirl imparters to impart a spiral motion to said gas-solid mixture facilitating the separation of said solid particles from said gas-solid mixture to obtain a cleaned gas ;
• collecting said solid particles in a collector zone of said gas-solid separator;
• allowing said cleaned gas to exit said axial swirl cone cyclone via said cleaned gas outlet conduit and get collected in a cleaned gas collecting zone of said gas-solid separator and discharged therefrom via a first outlet aperture of said gas-solid separator. ,TagSPECI:FIELD
The present disclosure relates to the field of mechanical engineering. In particular, the present disclosure relates gas-solid separators and a process for gas-solid separation.
DEFINITIONS
FEED herein means a gas-solid mixture such that the solid particles are entrained in the gas. The feed is supplied as an input to a gas-solid separator.
CLEANED GAS herein means a gas-solid mixture from which at least a portion of the solid particles have been removed.
BACKGROUND
Fluid Catalytic Cracking (FCC) process is a widely used refining process in a petroleum refinery. The FCC process is carried out to convert a high-boiling point and high-molecular weight petroleum crude oil to gasoline, olefinic gases, and other products. Petroleum crude oil is reacted with a hot catalyst for breaking it into by-products which are introduced in a reactor. In the reactor, the catalyst (spent catalyst) is separated from the by-products, and the recovered catalyst (spent catalyst) is regenerated with the help of hot air in a regenerator. The flue gas thus formed inside the regenerator is a mixture of gas formed by burning off deposition layers formed on the catalyst and the solid particles of the catalyst itself. The temperature of the flue gases, at this point, is typically in the range of 700oC-800oC, and hence there is still a lot of energy contained in the flue gases.
But the flue gases formed at this point are neither fit to be released to the atmosphere, nor can they be utilised for further use in devices like the turbines for generating power. This is because the flue gas contains entrained solid catalyst particles. To remove the entrained solid catalyst particles from the flue gas, a Third Stage Separator (TSS), which is generally a gas-solid separator, is employed. The TSS recovers the catalyst particles from the flue gas thereby making the flue gas suitable for use in conjunction with a turbine or for any other application. Thereafter the flue gas can be released into the atmosphere.
It is observed that the efficiency of gas-solid separation offered by a conventional gas-solid separator is low, thereby resulting in the entrained solid catalyst particles not being removed from the flue gas even after the separation process.
Moreover, conventional cyclones used in conventional the gas-solid separators involve the use of elements like stabilizer-pins and stabilizer plates or tangential slots, thus increasing the number of components inside the cyclone or clogging prone due to small slit sizes. The increased number of components results in a complicated configuration of the cyclone, which is not desired.
Hence, in order to address the aforementioned drawbacks, there is a need for a gas-solid separator which provides a high efficiency of separation for separating entrained solid particles from a gas.
SUMMARY
A gas-solid separator has a housing that has an operative top and an operative bottom. The housing has an inlet aperture formed on the operative top of the housing and configured to receive an inlet conduit. The inlet conduit has a first operative end and a second operative end. The first operative end of the inlet conduit is received in the inlet aperture such that it protrudes out of the housing, and the second operative end extends in an operative downward direction within the housing. The gas-solid separator further comprises a first outlet aperture formed on the operative top of the housing that facilitates the discharge of a cleaned gas, and a second outlet aperture formed on the operative bottom of the housing that facilitates the removal of the solid particles collected in the housing. The gas-solid separator also comprises a plurality of axial swirl cone cyclones. The axial swirl cone cyclone has a cyclone body having a cylindrical portion and a truncated conical portion extending from the cylindrical portion. The cylindrical portion defines a swirl zone and the conical portion defines a vortex zone. Another end of the vortex zone is truncated inside a deep cylindrical tube that defines a deep leg whose cross-sectional area is slightly greater than the cross-sectional area of the vortex zone outlet. In another embodiment, the other end of the deep leg may be connected with another smaller cone to prevent gas flow inside the cyclone from the bottom of the common catch zone. The axial swirl cone cyclone comprises a feed inlet formed on an operative upper end of the swirl zone, a cleaned gas outlet disposed within the feed inlet that defines an annular space between the feed inlet and cleaned gas outlet, and swirl imparters disposed in the annular space.
A process for gas-solid separation using the gas-solid separator is also disclosed in the present disclosure.
OBJECTS OF THE DISCLOSURE
Some of the objects of the present disclosure, which at least one embodiment herein satisfies are as follows:
It is an object of the present disclosure to ameliorate one or more problems of the conventional practices or to at least provide a useful alternative.
An object of the present disclosure is to provide a gas-solid separator that provides a high efficiency of gas-solid separation.
Another object of the present disclosure is to provide a gas-solid separator that facilitates capturing solid particles entrained in a gas.
Another object of the present disclosure is to provide a gas-solid separator that aids in reducing the environmental pollution.
Another object of the present disclosure is to provide a process for gas-solid separation.
Another object of the present disclosure is to provide gas-solid separator that facilitates lower damage of downstream equipment like turbine blades.
Yet another object of the present disclosure is to provide a gas-solid separator that is cost effective and exhibits an extended service life.
Other objects and advantages of the present disclosure will be more apparent from the following description when read in conjunction with the accompanying figure, which are not intended to limit the scope of the present disclosure.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
A gas-solid separator of the present disclosure will now be described with the help of accompanying drawings, in which:
Fig. 1 illustrates a schematic diagram of a gas-solid separator in accordance with the present disclosure;
Fig. 2 illustrates a schematic view of an axial swirl cone cyclone that is used in the gas-solid separator of Fig. 1 in accordance with the present disclosure.
DETAILED DESCRIPTION
A gas-solid separator and a process for gas-solid separation in accordance with the present disclosure will now be described with reference to the embodiments, which do not limit the scope and ambit of the disclosure. The description provided is purely by way of example and illustration. The embodiment herein, the various features, and advantageous details thereof are explained with reference to the non-limiting embodiments in the following 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.
Fig. 1 illustrates a schematic diagram of a gas-solid separator 1 in accordance with the present disclosure. The gas-solid separator 1 comprises a housing 10. The housing 10 has an operative top and an operative bottom. An inlet aperture, configured to receive an inlet conduit 11, is formed on the operative top of the housing 10, a first outlet aperture 14 is also formed on the operative top of the housing 10 which facilitates the discharge of a cleaned gas containing minute amounts of solid particles, and a second outlet aperture 15 formed on the operative bottom of the housing 10 that facilitates the removal of solid particles collected in the housing 10.
The housing 10 further comprises a first separator 18 and a second separator 19. The first separator 18 and the second separator 19 are disposed horizontally in the housing 10 in an axially spaced configuration. The first separator 18 and the second separator 19 divide the housing 10 in three parts, viz., a cleaned gas collecting zone 17, a flue gas-solid common feed header zone 13, and a common catch zone 16. The common catch zone 16 is defined in the portion operatively below the second separator 19, the cleaned gas collecting zone 17 is defined in a portion operatively above the first separator 18, and the flue gas-solid common feed header zone 13 is defined in a portion operatively between the first separator 18 and the second separator 19. The cleaned gas collecting zone 17 is adapted to receive the cleaned gas containing minute amounts of entrained solid particles. The solid particles that are separated from the feed are collected in the common catch zone 16. The flue gas-solid common feed header zone 13 is adapted to receive the feed via the inlet conduit 11. The first separator 18 prevents the mixing of the cleaned gas collected in the cleaned gas collecting zone 17 and the feed that is introduced in the flue gas-solid common feed header zone 13. The second separator 19 prevents the mixing of the feed introduced in the flue gas-solid common feed header zone 13 and the solid particles present in the common catch zone 16. The first separator 18 and the second separator 19 are also configured to support a plurality of axial swirl cone cyclones 2a, 2b, 2c. The plurality of axial swirl cone cyclones 2a, 2b, 2c,…, are disposed within the housing 10 such that the feed is received inside the plurality of axial swirl cone cyclones 2a, 2b, 2c, …, and so on.
The inlet conduit 11 has a first operative end 11a and a second operative end 11b. The first operative end 11a of the inlet conduit is configured to receive the feed, and the second operative end 11b of the inlet conduit 11 is sealed. The inlet conduit 11 is disposed in inlet aperture of the housing 10 such that its first operative end 11a protrudes out of the housing 10 and its second operative end is extended in an operative downward direction within the housing 10. The inlet conduit 11 has a plurality of feed distributor openings 12a, 12b, 12c…, which are formed near the second operative end 11b thereof, are in fluid communication with the flue gas-solid common feed header zone 13.The feed is introduced inside the flue gas-solid common feed header zone 13 via the plurality of feed distributor openings 12a, 12b, 12c…, of the inlet conduit 11.
Fig. 2 illustrates a schematic view of an axial swirl cone cyclone 2 that is disposed in the gas-solid separator 1 in accordance with the present disclosure. The axial swirl cone cyclone 2 has a cyclone body 29 that has a cylindrical portion and a truncated conical portion extending coaxially from the cylindrical portion. The cylindrical portion defines a swirl zone (zone 20) and the conical portion defines a vortex zone 21. A deep leg 22, having cross-sectional area slightly greater than the cross-sectional area of the vortex zone outlet, is disposed at an operative bottom end of the vortex zone 21. The axial swirl cone cyclone 2 has a feed inlet 24 formed on the operative upper end 20a of the swirl zone 20, a cleaned gas outlet 26 disposed concentrically with the feed inlet 24 such that the cleaned gas outlet 26 defines an annular space between the feed inlet 24 and the cleaned gas outlet 26, swirl imparters 27 disposed in said annular space operatively below the feed inlet 24, and an outlet 25 formed in an operative end of the deep leg 22 to facilitate the removal of the solid particles collected therein. In another embodiment, the other end of the deep leg may be connected with another smaller cone to prevent gas flow inside the cyclone from the bottom of the common catch zone.
The process for separation of solid particles from a gas-solid mixture is now described in the following sections. Firstly the gas-solid mixture is introduced in into the flue gas-solid common feed header zone 13 of the gas-solid separator 1. The plurality of axial swirl cone cyclones 2a, 2b, 2c… is provided and disposed within the gas-solid separator 1. The axial swirl cone cyclone comprises a cleaned gas outlet conduit 26, a swirl zone 21, swirl imparters 27, and a vortex zone 21, such that the swirl zone 21 is in fluid communication with the flue gas-solid common feed header zone 13, and the swirl zone is adapted to receive the gas-solid mixture. The swirl imparters 27 are allowed to impart a spiral motion to the gas-solid mixture for facilitating the separation of the solid particles from the gas-solid mixture to obtain a cleaned gas. The solid particles are collected in a collector zone 16 of the gas-solid separator 1. The cleaned gas is allowed to exit the axial swirl cone cyclone via the cleaned gas outlet conduit 26 and get collected in the cleaned gas collecting zone 10 of the gas-solid separator 1 and discharged therefrom via the first outlet aperture 14 of the gas-solid separator 1.
The operation of the gas-solid separator 1 will now be described, in further detail, with reference to Fig. 1 and Fig. 2. The feed (gas-solid mixture) is introduced in the gas-solid separator 1 via the inlet conduit 11. The inlet conduit 11 is in fluid communication with the flue gas-solid common feed header zone 13. The feed is introduced inside the flue gas-solid common feed header zone 13 via the plurality of feed distributor openings 12a, 12b, 12c…, formed on the inlet conduit 11 near the second operative end 11b of the inlet conduit 11. A plurality of the axial swirl cone cyclones 2a, 2b, 2c…, is received by the first separator 18 and a second separator 19 such that the feed inlet 24 of the axial swirl cone cyclone 2 is in fluid communication with the flue gas-solid common feed header zone 13 and the cleaned gas outlet 26 is in fluid communication with the cleaned gas collecting zone 17.
Referring to Fig. 2, the feed enters the axial swirl cone cyclone 2 via the feed inlet 24. The swirl imparters 27 impart a swirling motion to the feed, and as the feed advances operatively downwards inside the swirl zone 20, the angular velocity, with which the feed is moving in a spiral motion, increases. As the angular velocity increases, the centrifugal force associated with the feed also increases. As the feed enters the vortex zone 21, the spiral motion keeps the solid particles separate from the cleaned gas upflowing while dragging solid particles towards bottom of the axial swirl cone cyclone. This process prevents the solid re-entraining in the cleaned gas which is channelized towards outlet of the cyclone. The motion of the solid particles slows down, and the solid particles tend to fall down inside the deep leg 22 where gas velocity decreases due to increase in flow area and separated particles are carried out towards common catch zone 16.
Meanwhile, the angular velocity of the cleaned gas, formed inside the vortex zone 21 after the separation of the solid particles from the feed, also decreases. The decreased angular velocity of the cleaned gas results in the formation of a natural duct inside the vortex zone 21 (denoted by arrows inside the vortex zone 21). The cleaned gas thus formed inside the vortex zone 21 exits the vortex zone 21 through the natural duct and enters the swirl zone 20, wherefrom it enters the cleaned gas outlet 26 and is ultimately collected in the cleaned gas collecting zone 17 in the housing 10.
All the axial swirl cone cyclones 2 in the plurality of the axial swirl cyclone operate in this manner, and the solid particles collected in the deep legs 22 of all the axial swirl cone cyclones 2 are then received in the common catch zone 16 and removed therefrom via the second aperture 15 that is formed on the operative bottom of the housing 10. The cleaned gas, containing minute amounts of solid particles, discharged from the axial swirl cone cyclones 2 is collected in the cleaned gas collecting zone 17, and subsequently discharged through the first outlet aperture 14 of the gas-solid separator 1.
The operation of the plurality of axial swirl cone cyclones 2a, 2b,…, and the separators 18, 19 inside the housing 10 of the gas-solid separator 1 of the present disclosure, facilitate in the obtainment of a separation efficiency that is significantly improved as compared with the conventional separators. As the separation efficiency is increased, a higher amount of solid particles entrained in the feed are captured. These particles can be recovered and are prevented from being released directly into the atmosphere. This results in reduced environmental pollution.
All the openings in the gas-solid separator 1 of the present disclosure have a diameter of at least 80mm. Such a configuration of openings results in reduced clogging and choking of the solid particles inside the openings.
Furthermore, the configuration of the axial swirl cone cyclone 2, that is to be used in the gas-solid separator 1, is such that it comprises a very small number of different components, unlike the conventional cyclones which have elements like stabilizer-pins and stabilizer plates. The reduced number of components in the axial swirl cone cyclone 2 of the present disclosure has resulted in a significantly reduced cost and a significantly simple operation. The less number of components and the simplified operation of the axial swirl cone cyclone 2 results in an extended service life of the axial swirl cone 2, and ultimately an extended service life of the gas-solid separator 1 of the present disclosure. Moreover, with such a simple configuration, the axial swirl cone cyclone 2 of the present disclosure can also be retro-fitted in existing gas-solid separators with minimal modification.
TECHNICAL ADVANCEMENTS AND ECONOMIC SIGNIFICANCE
The gas-solid separator 1, in accordance with the present disclosure described herein above has several technical advantages including but not limited to the realization of a gas-solid separator that:
• provides a high efficiency of gas-solid separation;
• has a plurality of axial swirl cone cyclones;
• has reduced clogging;
• facilitates capturing solid particles entrained in a gas;
• aids in reducing the environmental pollution;
• is cost effective and exhibits extended service life;
• facilitates lower damage of downstream equipment such as turbine blades
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 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 mixture 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 or 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 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.