Description:FIELD OF THE INVENTION
The present invention relates to a reactor and a process for producing CNT and in particular relates to a reactor and a process for producing CNT in a semi continuous mode.
BACKGROUND OF THE INVENTION
Conventionally CNT produced from either fixed bed type of reactors or Fluidized bed reactors. Fixed bed reactor having the flexibility to provide sufficient residence time for continuous growth of CNT, but it has own limitation in throughput-. Fixed bed reactor provides sufficient residence time for continuous growth of CNT. But this is operated in batch mode. In batch operation after completion of reaction, the reactor has to be cooled for CNT evacuation. So, throughput is limited by reactor cooling and then followed by heating up to the required process temperature. Further, batch process consumes more energy than continuous process. Contrary to the fixed bed reactor, fluidized bed reactor provides continuous mode of operation, but it provides limited residence time and growth of CNT. So, CNT produced from Fluidized bed having higher metal impurities (catalyst). Fluidized bed reactor can be operated in continuous mode, but it has limitation in reactor residence time of feed vapor and hence having limited CNT growth per gm of catalyst. Due to limited CNT growth, the product is having higher metal impurity.
US patent No 7563427 disclosed a method of Continuous production of CNT using fluidized bed reactor.
US Patent No 8911701 disclosed a method of producing CNT and discharge the CNT in hot condition using fluidized bed reactor.
US Patent No 9687802 disclosed a method of producing CNT and separating the byproduct gases using fluidized bed reactor
US Patent No 10457556 disclosed a method of producing CNT in fluidized bed reactor and further discussed about maintaining the fluidity of the reactor by partial withdrawal of CNT from the reactor
US patent No 9206050 disclosed a method of producing CNT using chemical vapor deposition with a mechanism of continuous feeding of catalyst in the reactor
US patent No 6905544 disclosed a method of producing CNT using fluidized bed reactor with the provision of separator to separate the solid particles from product gaseous stream
US patent No 9650251 disclosed a method for efficient production of the solid carbon material by way of a reduction reaction between at least one carbon oxide and at least
Fixed bed reactor provides sufficient residence time for continuous growth of CNT. But this can be operated in batch mode. In batch operation, after completion of reaction, the reactor to be cooled for CNT evacuation. So, throughput is limited by Fixed bed reactor cooling and then followed by heating up to the required process temperature. So, the batch process is energy intensive. Contrary fluidized bed reactor provides continuous mode of operation, but it provides limited residence time and growth of CNT per gram of catalyst. So, CNT produced from Fluidized bed reactor have higher metal impurities (catalyst).
However present invention deals with a reactor and process for production of CNT to overcome the above-mentioned issues in batch and fluidization process of production of CNT.
OBJECTIVES OF THE INVENTION
The main objective of this invention is to provide a reactor for producing CNT.
Another objective of the invention is to provide a reactor for producing CNT in a semi continuous mode.
Another objective of the invention to provide a reactor for producing CNT in a semi continuous mode wherein the reactor comprises a Catalyst preheating zone, a Catalyst activation zone, a CNT reaction zone, a CNT cooling zone and a CNT evacuation or collection zone/vessel wherein the CNT reaction zone further comprises of a CNT growth zone and a Feed vaporizer zone.
Another objective of the invention to provide a reactor for producing CNT in a semi continuous mode wherein the zones of the reactor comprise a plurality of knife gate valves adapted to isolate individual zones of the reactor.
Another objective of the invention to provide a reactor for producing CNT in semi continuous mode wherein each zone is separated by a knife gate valve.
Another objective of the invention to provide a reactor for producing CNT in semi continuous mode wherein a knife gate valve is used for supporting the catalyst in the catalyst pre-heater zone. Further, the knife gate valve is used to transfer the catalyst from catalyst pre heater zone to catalyst activation zone.
Another objective of the invention to provide a reactor for producing CNT in semi continuous mode wherein the pre-heater zone is available for preheating the next batch of catalyst after evacuation of catalyst from the catalyst pre heater zone to catalyst activation zone
Another objective of the invention to provide a reactor for producing CNT in semi continuous mode wherein the catalyst preheating zone minimizes the catalyst sintering .
Another objective of the invention to provide a reactor for producing CNT in semi continuous mode wherein the catalyst is activated in catalyst activation zone. The preheated catalyst is directly fed from catalyst preheater zone to catalyst activation zone. After completion of activation, the catalyst is transferred from catalyst activation zone to CNT reactor zone with the help of a knife gate valve.
Another objective of the invention to provide a reactor for producing CNT in semi continuous mode wherein the activation zone is available for activation of next batch catalyst after evacuation of catalyst from activation to reaction zone
Another objective of the invention to provide a reactor for producing CNT in semi continuous mode wherein the reaction zone is further divided in to two zones as CNT growth zone and Feed vaporization zone
Another objective of the invention to provide a reactor for producing CNT in semi continuous mode wherein the CNT growth zone facilitates the reaction between the feed mixture and catalyst. Feed is catalytically decomposed, and CNT is grown on the catalyst in presence of an inert atmosphere.
Another objective of the invention to provide a reactor for producing CNT in semi continuous mode wherein the CNT growth zone in which catalyst is fed, comprises of a catalyst-feed distributor plate comprising of a perforated plate, a mesh adapted to hold the catalyst and a support ring, wherein the catalyst-feed distributor plate is adapted for removal and replacement of the mesh.
Another objective of the invention to provide a reactor for producing CNT in semi continuous mode wherein the feed is continuously fed. After reaction time the feed is cutoff from the reactor.
Another objective of the invention to provide a reactor for producing CNT in semi continuous mode wherein the feed vapor mixture containing inert gas is prepared in the feed vaporization zone.
Another objective of the invention to provide a reactor for producing CNT in semi continuous mode wherein the feed vapor mixture containing inert gas enters from the feed vaporization zone to the CNT growth zone for catalytic reaction by means of a perforated plate with a mesh arrangement of the catalyst-feed distributor plate.
Another objective of the invention to provide a reactor for producing CNT in semi continuous mode wherein the CNT growth zone contains a stirrer with to and fro movement or a piston which is used for uniform dispersion of catalyst across the catalyst catalyst-feed distributor plate of the reactor. Further, the stirrer is used continuously or intermittently to break the CNT lump formation during the reaction for evacuation of CNT from reaction after completion of reaction.
Another objective of the invention to provide a reactor for producing CNT in semi continuous mode wherein the knife gate valves of the CNT growth zone and feed vaporization zone is in closed position during the reaction, and it will be in open position during CNT evacuation.
Another objective of the invention to provide a reactor for producing CNT in semi continuous mode wherein after the completion of the reaction, the knife gate valves present at the bottom of CNT growth zone and feed vaporization zone are opened simultaneously and the knife gate valve present in the bottom of the CNT cooling zone is in closed position.
Another objective of the invention to provide a reactor for producing CNT in semi continuous mode wherein the CNT reaction zone is available for reaction after evacuation of CNT from the reaction zone to the CNT cooling zone
Another objective of the invention to provide a reactor for producing CNT in semi continuous mode wherein the CNT cooling zone contains nitrogen purging inside the cooling zone as well as an external jacketed heat exchanger in which cold fluid is flowed in and out to cool the CNT.
Another objective of the invention to provide a reactor for producing CNT in semi continuous mode wherein the cooled CNT from the CNT cooling zone is transferred to the CNT collection zone/vessel with the help of a knife gate valve. During this operation, all other knife gate valves are closed except knife gate valve present at the bottom of the CNT cooling zone.
Another objective of the invention to provide a reactor for producing CNT in semi continuous mode wherein the CNT production and evacuation is without cooling of catalyst pre-heater, catalyst activation, CNT reaction zones. At any point of time, every zone of the reactor will be occupied with either catalyst or CNT with their respective reactions to improve the through put and consume less energy.
Another objective of the invention to provide a reactor for producing CNT in semi continuous mode wherein the catalyst-feed distributor plate is a combination of perforated plate, mesh and a support ring. The perforated plate and support ring are sandwiched to hold the mesh through a different locking mechanism. This mechanism allows the easy maintenance of distributor and replacement of mesh without opening of the reactor.
Another objective of the invention to provide a process to produce Carbon Nano tube (CNT) by a reactor in a semi-continuous mode.
Another objective of the invention to provide a reactor for producing CNT in semi continuous mode wherein the process time of each zone is 2 hour to 18 hour depending on other zone’s operation.
Another objective of the invention to provide a reactor for producing CNT in semi continuous mode using a feed as crude oil or its products or C1-C5 gases such as methane, ethane, ethylene, propane, propylene, butane, butylenes and its isomers or mixture thereof.
Another objective of the invention is to provide a reactor for producing CNT in a semi continuous mode having low metal impurities (catalyst) and high yield.
Another objective of the invention to provide a reactor for producing CNT in a semi continuous mode wherein there is no need of cooling the reactor for CNT evacuation and the reactor is simultaneously ready for another batch.
Another objective of the invention to provide a reactor for producing CNT in a semi continuous mode wherein at any point of time, every zone of reactor will be occupied with either catalyst or CNT with their respective reactions to improve the through put and consume less energy.
One more embodiment of the present invention preheater zone, Activation zone, CNT reaction zone and Feed vaporizer zone, CNT cooling zone, Collection zone cycle time is maintained in the range of 2 hour to 18 hour.
SUMMARY OF THE INVENTION
This summary is provided to introduce a selection of concepts, in a simplified format, that are further described in the detailed description of the invention. This summary is neither intended to identify key or essential inventive concepts of the invention and nor is it intended to determine the scope of the invention.
The present invention provides a semi continuous reactor which comprises a catalyst preheating zone, a catalyst activation zone, a CNT reaction zone, a CNT cooling zone and a CNT evacuation or collection zone/ vessel, wherein the CNT reaction zone further comprises of a CNT growth zone and a Feed vaporizer zone for semi continuous production of CNT without cooling the reactor for CNT evacuation thus providing sufficient residence time for CNT growth as well as less energy consumption and improve throughput of the reactor with less metal impurity. In the proposed reactor, catalyst sintering is avoided by using of catalyst preheater zone and avoiding direct exposure of high temperature. In the semi continuous reactor, each zone is separated by a knife gate valve and simultaneously each zone operates on different process conditions. At any point of time, every zone of rector will be occupied with either catalyst or CNT with their respective reactions to improve the through put and consume less energy. The present invention also provides a process to produce Carbon Nano tube (CNT) in a semi-continuous mode by a reactor.
In one of the embodiment, the invention provides a reactor (100, 100-1) for producing Carbon Nano tube (CNT) in semi-continuous mode comprising;
a) a manual catalyst feed section (1) adapted to feed the catalyst into the reactor;
b) a catalyst preheating zone (2) adapted for continuous preheating of the catalyst;
d) a catalyst activation zone (5) adapted for continuous activation of the catalyst;
e) a Carbon Nano tube (CNT) reaction zone (8A) adapted to facilitates the reaction between a feed mixture and the activated catalyst, which further comprises of;
(i) a Carbon Nano tube (CNT) growth zone (8) adapted to facilitates the reaction between the feed mixture and the catalyst wherein the feed mixture is catalytically decomposed, and CNT is grown on the catalyst in presence of an inert atmosphere ;
(ii) a Feed vaporizer zone (12) adapted for vaporisation of the feed, wherein the feed vapor mixture containing an inert gas that enters from feed vaporization zone (12) to the Carbon Nano tube (CNT) growth zone for catalyst reaction;
f) a Carbon Nano tube (CNT) cooling zone (14) adapted to cool the produced CNT; and
g) a Carbon Nano tube (CNT) collection zone/vessel (17) adapted to collect the produced Carbon Nano tube (CNT);
wherein the zones of the reactor comprise a plurality of knife gate valves adapted to isolate individual zones.
In another embodiment, the invention provides a reactor for producing Carbon Nano tube (CNT) in semi-continuous mode wherein the CNT growth zone comprises of a catalyst-feed distributor plate comprising of a perforated plate, a mesh adapted to hold the catalyst and a support ring, wherein the catalyst-feed distributor plate is adapted for removal and replacement of the mesh.
In another embodiment, the invention provides a reactor for producing Carbon Nano tube (CNT) in semi-continuous mode wherein a knife gate valve supports movable catalyst-feed distributor plate for CNT growth.
In another embodiment, the invention provides a reactor for producing Carbon Nano tube (CNT) in semi-continuous mode wherein the wherein the perforated plate and support ring are sandwiched to hold the mesh through a plurality of locking mechanisms.
In another embodiment, the invention provides a reactor for producing Carbon Nano tube (CNT) in semi-continuous mode wherein the perforated plate and support ring are sandwiched to hold the mesh through lock and rotate mechanism wherein an outside diameters D1, D2, D3 of perforated plate, mesh and O - ring are equal before and after fixing of the mesh.
In another embodiment, the invention provides a reactor for producing Carbon Nano tube (CNT) in semi-continuous mode wherein the perforated plate and support ring are sandwiched to hold the mesh through lock and rotate mechanism wherein a slot on the perforated plate inner diameter D2 is equal to inner diameter D4 of O-ring and outer diameter D1 of perforated plate is equal to outer diameter D3 of mesh.
In another embodiment, the invention provides a reactor for producing Carbon Nano tube (CNT) in semi-continuous mode wherein an overhead stirrer or a piston arrangement for uniform spreading of catalyst over catalyst-feed distributor plate for high yield of CNT and also for breaking the CNT lumps for easy evacuation CNT from reactor.
In another embodiment, the invention provides a reactor for producing Carbon Nano tube (CNT) in semi-continuous mode wherein there is continuous pre-heating and activation of the catalyst.
In another embodiment the invention provides a reactor for producing Carbon Nano tube (CNT) in semi-continuous mode wherein each zone is separated by a knife gate valve thus facilitating each zone to operate different process conditions simultaneously in a single reactor.
In another embodiment, the invention provides a reactor for producing Carbon Nano tube (CNT) in semi-continuous mode wherein CNT is cooled using cooling zone in same reactor.
In another embodiment, the present invention provides a process to produce Carbon Nano tube (CNT) in a semi-continuous mode by the reactor (100, 100-1) as claimed in claim 1, comprising the following steps;
- Feeding a catalyst into the pre-heater zone (4) through the manual catalyst feed section (1) at atmospheric conditions;
- Preheating the catalyst in the catalyst preheater zone (4) at a temperature of 200o-400 o C in an inert atmosphere for 4 to 18 hours;
- Feeding the preheated catalyst from the catalyst preheater zone (4) to the catalyst activation zone (5) by opening a knife gate valve (4) of the catalyst pre-heater zone (4);
- Closing the knife gate valve (4) of the catalyst pre-heater zone;
- Heating the catalyst activation zone (5) to maintain a temperature in the range of 400 o C to 750 o C;
- Activating the catalyst in the catalyst activation zone (5) for 4 to 18 hour by mixing hydrogen and nitrogen gas mixture from an inlet (6);
- Transferring the activated catalyst from the catalyst activation zone (5) to the Carbon Nano tube (CNT) reaction zone (8) by opening a knife gate valve (7) at the bottom of the catalyst activation zone (5);
- Closing the knife gate valve (7) of the catalyst activation zone (5) after transferring the activated catalyst to the Carbon Nano tube (CNT) reaction zone (8);
- Heating the Carbon Nano tube (CNT) growth zone (8) of the Carbon Nano tube (CNT) reaction zone (8) to maintain a temperature in the range of 550o-900o C
- Feeding a preheated feed and nitrogen mixture into the feed vaporizer zone (12) continuously for 2 hours to 18 hours;
- Heating the feed vaporizer zone to maintain a temperature in the range of 550 o to 900 o C;
- Mixing the feed vapors from the feed vaporization zone (12) through the mesh (30, 36) of the Catalyst –Feed distributor plate (10, 27, 36) with the activated catalyst in the Carbon Nano tube (CNT) growth zone (8) for CNT growth;
- Purging the CNT growth zone (8) and feed vaporizer zone (12) with nitrogen or inert gas to remove the traces of hydrogen present in the CNT growth zone (8) and feed vaporizer zone (12);
- Stirring the activated catalyst uniformly by the evacuation stirrer (20) and a CNT reactor Piston (25) arrangement over the Catalyst –Feed distributor plate (10, 27, 36) and breaking the CNT lumps;
- Evacuating the produced CNT from (CNT) growth zone (8) and feed vaporization zone (12) to the cooling zone (14) by opening a knife gate valve (11) at the bottom of the (CNT) growth zone (8) and a knife gate valve (13) at the feed vaporization zone (12);
- Cooling the produced CNT in the cooling zone (14) using nitrogen or inert gas from inlet (15) and external jacketed heat exchanger (18) for 2 hour to 8 hour;
- Collecting CNT in the collection vessel (17) by opening a knife gate valve (16) at the bottom of the cooling zone (14).
To further clarify the advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof, which is illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. The invention will be described and explained with additional specificity and detail with the accompanying drawings.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
These and other features, aspect, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
Figure 1 and Figure 2 illustrate shows reactor design for the production of CNT according to an embodiment of the present disclosure;
Figure 3 illustrates a design of a knife gate valve comprising of a catalyst-feed distributor plate according to an embodiment of the present disclosure. This catalyst-feed distributor plate has a pull and push mechanism to lock the mesh between perforated plate and ring according to an embodiment of the present disclosure;
Figure 4 illustrates a design of knife gate valve comprising of a Catalyst and feed distributor plate according to another embodiment of the present disclosure. This catalyst-feed distributor plate has a lock and rotates mechanism to lock the mesh between perforated plate and ring, according to an embodiment of the present disclosure;
Figure 5 illustrates reactor design for the production of CNT with preheater and catalyst activation section with linear vertical alignment according to an embodiment of the present disclosure;
Figure 6a illustrates Transmission Electron Microscope analysis (TEM) of CNT obtained; and
Figure 6b illustrates Raman Spectra analysis of CNT obtained;
DETAILED DESCRIPTION OF THE INVENTION
For the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated system, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skilled in the art to which this invention belongs. The system, methods, and examples provided herein are illustrative only and not intended to be limiting.
The term “some” as used herein is defined as “none, or one, or more than one, or all.” Accordingly, the terms “none,” “one,” “more than one,” “more than one, but not all” or “all” would all fall under the definition of “some.” The term “some embodiments” may refer to no embodiments or to one embodiment or to several embodiments or to all embodiments. Accordingly, the term “some embodiments” is defined as meaning “no embodiment, or one embodiment, or more than one embodiment, or all embodiments.”
The terminology and structure employed herein is for describing, teaching and illuminating some embodiments and their specific features and elements and does not limit, restrict or reduce the spirit and scope of the claims or their equivalents.
More specifically, any terms used herein such as but not limited to “includes,” “comprises,” “has,” “consists,” and grammatical variants thereof do NOT specify an exact limitation or restriction and certainly do NOT exclude the possible addition of one or more features or elements, unless otherwise stated, and furthermore must NOT be taken to exclude the possible removal of one or more of the listed features and elements, unless otherwise stated with the limiting language “MUST comprise” or “NEEDS TO include.”
Whether or not a certain feature or element was limited to being used only once, either way, it may still be referred to as “one or more features” or “one or more elements” or “at least one feature” or “at least one element.” Furthermore, the use of the terms “one or more” or “at least one” feature or element do NOT preclude there being none of that feature or element, unless otherwise specified by limiting language such as “there NEEDS to be one or more . . . ” or “one or more element is REQUIRED.”
Unless otherwise defined, all terms, and especially any technical and/or scientific terms, used herein may be taken to have the same meaning as commonly understood by one having ordinary skills in the art.
Reference is made herein to some “embodiments.” It should be understood that an embodiment is an example of a possible implementation of any features and/or elements presented in the attached claims. Some embodiments have been described for the purpose of illuminating one or more of the potential ways in which the specific features and/or elements of the attached claims fulfil the requirements of uniqueness, utility and non-obviousness.
Use of the phrases and/or terms such as but not limited to “a first embodiment,” “a further embodiment,” “an alternate embodiment,” “one embodiment,” “an embodiment,” “multiple embodiments,” “some embodiments,” “other embodiments,” “further embodiment”, “furthermore embodiment”, “additional embodiment” or variants thereof do NOT necessarily refer to the same embodiments. Unless otherwise specified, one or more particular features and/or elements described in connection with one or more embodiments may be found in one embodiment, or may be found in more than one embodiment, or may be found in all embodiments, or may be found in no embodiments. Although one or more features and/or elements may be described herein in the context of only a single embodiment, or alternatively in the context of more than one embodiment, or further alternatively in the context of all embodiments, the features and/or elements may instead be provided separately or in any appropriate combination or not at all. Conversely, any features and/or elements described in the context of separate embodiments may alternatively be realized as existing together in the context of a single embodiment.
Any particular and all details set forth herein are used in the context of some embodiments and therefore should NOT be necessarily taken as limiting factors to the attached claims. The attached claims and their legal equivalents can be realized in the context of embodiments other than the ones used as illustrative examples in the description below.
Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
While the invention is susceptible to various modifications and/or alternative adaptations, specific embodiment thereof has been shown by way of examples and will be described in detail below. However, it should be understood, that it is not intended to limit the invention to the particular structural arrangement disclosed, but on the contrary, the invention is to cover all modifications, structural adaptations and alternative falling within the spirit and the scope of the invention as defined herein.
Figure 1 and 2 illustrates a design of a reactor (100, 100-1) according to an embodiment of the present disclosure. The reactor (100, 100-1) is employed for semi continuous production of CNT. The reactor (100, 100-1) may provide an alternative to fixed bed and fluidized bed production of CNT. The reactor (100, 100-1) may be adapted to provide an alternate to CNT production with sufficient residence time for CNT growth as well are for efficient energy consumption and improved throughput. Constructional and operation details of the reactor (100, 100-1) and process to produce CNT in a semi continuous mode is by the reactor (100, 100-1) are explained in subsequent sections of the present disclosure.
Referring to Figure 1 and 2 of the present disclosure, a reactor (100, 100-1) may include a manual catalyst feed section (1) adapted to feed a catalyst into the reactor (100, 100-1) wherein the catalyst feed section (1) may be ball valve or gate valve. However, it should be appreciated by a person skilled in the art that the design of the manual catalyst feed section (1) should not be construed as limiting without departing from the scope of the present disclosure.
The reactor (100, 100-1) may include a catalyst preheating zone (2) adapted for continuous preheating of the catalyst and a catalyst activation zone (5) adapted for continuous activation of the catalyst. The catalyst preheating zone (2) and the catalyst activation zone (5) is separated by knife gate valve (4) that facilitates the transfer of preheated catalyst from the catalyst preheating zone (2) to the catalyst activation zone (5). The catalyst preheating zone (2) and the catalyst activation zone (5) has inlets (3) and (6) respectively for inert gases like Nitrogen or Argon or mixtures thereof.
The reactor (100, 100-1) may include a Carbon Nano tube (CNT) reaction zone (8A) adapted to facilitates the reaction between a feed mixture and the activated catalyst for producing CNT. The catalyst activation zone (5) and the Carbon Nano tube (CNT) reaction zone (8A) of the reactor (100, 100-1) is separated by a knife gate valve (7) that facilitates the transfer of activated catalyst from the catalyst activation zone (5) to the Carbon Nano tube (CNT) reaction zone (8A). After the activated catalyst is transferred to the Carbon Nano tube (CNT) reaction zone (8A) from the catalyst activation zone (5), the knife gate valve (7) is closed.
The Carbon Nano tube (CNT) reaction zone (8A) may include a Carbon Nano tube (CNT) growth zone (8) and a Feed vaporizer zone (12). The Carbon Nano tube (CNT) growth zone (8) may be adapted to facilitates the reaction between the feed mixture and catalyst wherein the feed mixture is catalytically decomposed, and CNT is grown on the catalyst in presence of an inert atmosphere. The Feed vaporizer zone (12) is adapted for vaporisation of the feed, wherein the feed vapor mixture may include a preheated feed and nitrogen mixture (19). The feed vapor mixture enters from feed vaporization zone (12) to the Carbon Nano tube (CNT) growth zone (8) for catalyst reaction and production of CNT.
The Carbon Nano tube (CNT) growth zone (8) and feed vaporization zone (12) are separated by a knife gate valve (11). The knife gate valve (11) of the Carbon Nano tube (CNT) growth zone (8) comprises of a Catalyst–Feed distributor plate (10, 27, 36) that further comprises of a perforation plate (28, 34), a mesh (30, 36) adapted to hold the activated catalyst and a support ring (32,37), wherein the Catalyst–Feed distributor plate (10, 27, 36) is adapted for removal and replacement of the mesh (30, 36). The mesh (30, 36) size ranges from 10 micron to 50 micron. This allows only vapor to pass through via mesh but at the same time it would not allow liquid to pass through.
The (CNT) growth zone (8) and feed vaporization zone (12) are adapted to be purged with nitrogen or inert gas after completion of CNT growth, to remove traces of hydrogen present. The reactor includes evacuation stirrer (20) and a CNT reactor Piston (25) arrangement for uniform spreading of catalyst over Catalyst –Feed distributor plate (10) for high yield of CNT. The evacuation stirrer (20) and a CNT reactor Piston (25) arrangement are also used for breaking the CNT lumps to easy evacuation of CNT from the Carbon Nano tube (CNT) growth zone (8) and feed vaporization zone (12) to a cooling zone (14) of the reactor (100, 100-1). The CNT reactor Piston (25) is adapted to evacuates the CNT product from reactor (100, 100-1) after the end of reaction by moving the CNT reactor Piston (25) from top to bottom of (CNT) growth zone (8).
The Cooling zone (14) is adapted to cool the produced CNT in the Carbon Nano tube (CNT) reaction zone (8A). The cooling zone (14) contains nitrogen inlet (15) adapted for purging nitrogen gas, and an external jacketed heat exchanger (18) with water intel to cool the CNT. The feed vaporization zone (12) is separated from the cooling zone (14) by a knife gate valve (13).
The knife gate valves (7), 11) and (13) are in closed position during the reaction in Carbon Nano tube (CNT) reaction zone (8A) that include the CNT) growth zone (8) and the feed vaporization zone (12).
After removing traces of hydrogen, the solid product CNT is evacuated from the (CNT) growth zone (8) and feed vaporization zone (12) by opening the knife gate valves (11) at the bottom of CNT) growth zone (8) and knife gate valves (13) at the bottom of feed vaporization zone (12). The knife gate valves (11) and (13) are kept at opened position during the evacuation from the Carbon Nano tube (CNT) reaction zone (8A) to the Cooling zone (14). After cooling in the Cooling zone (14), the CNT is collected in a collection zone/vessel (17) adapted to collect the produced Carbon Nano tube (CNT) by opening of a knife gate valve (16) at the bottom of the Cooling zone (14) .
The reactor (100, 100-1) may include a product gas out let (21) connected to a separator (22) to separate if any carry over CNT in the product stream in bottom of separator (22). The separated gaseous stream is sent for recycle or vented out in to the atmosphere. Simultaneously preheated feed and nitrogen mixture (19) fed into the feed vaporizer zone (12).
In another embodiment of the present invention the Carbon Nano tube (CNT) growth zone (8) of the reactor (100, 100-1) may include a Catalyst –Feed distributor plate (10, 27, 33) further comprising a perforation plate (28, 34), and support ring (32, 37) that are sandwiched to hold the mesh (30, 36) through a locking mechanism. This mechanism allows the easy maintenance of Catalyst –Feed distributor plate (10, 27,33) and replacement of mesh (30, 36). The mesh (30, 36) is sandwiched between a perforation plate (28, 34) and a support ring (32,37). The support ring (32,37) has slits to fit in the Catalyst –Feed distributor plate (10, 27, 33) with locking extensions and the support ring (32,37) will be rotated to avoid the slipping of support ring (32,37) during high temperature operation. After several runs, the mesh (30, 36) can be replaced by rotating the support ring (32,37) in opposite direction to unlock.
In another embodiment of the present invention as illustrated in FIG. 3 relates to the Catalyst –Feed distributor plate (27). As represented in FIG. 3, a mesh (30) is placed between a Catalyst –Feed distributor plate (27) also called as knife gate valve plate (27) and a support ring (32). The Catalyst –Feed distributor plate (27) further includes a perforation plate (28) that has multiple holes /perforations to so that the feed vapors can pass through it. The perforation plate (28) may include a circular slot (29) adapted to fit the support ring (32). This support ring (32) may include an open slit (31) adapted to stretch the support ring (32) outwards to fit it in the slot (29) of the perforation plate (28) so that the mesh (30) is locked between Catalyst –Feed distributor plate (27) and the support ring (32). The circular slot (29) on the perforated plate (28) has an outer diameter of D1 and inner diameter of D2, the mesh has an outer diameter of D3, and support ring has an inner diameter of D4 wherein the slot on perforated plate (28) with an inner diameter D2 is equal to inner diameter D4 of the support ring and outer diameter D1 of perforated plate is equal to outer diameter D3 of mesh. Hence, before the assembly of the perforated plate (28), the mesh (30) and support ring (32) have diameters as D3>D1>D2>D4 and after the assembly, the perforated plate (28), the mesh (30) and support ring (32) have diameters as D4=D2 and D1=D3.
In another embodiment of the present invention as illustrated in FIG. 4 illustrates a Catalyst –Feed distributor plate (33), wherein a mesh (36) is placed between a perforation plate (34) and a support ring (37). The Catalyst –Feed distributor plate (33), includes a perforation plate (34) that has multiple holes/perforations and three locking extensions (35). The perforations are for the feed vapors to pass through it and three locking extensions (35 ) are adapted to match the three slits (38) of the support ring (37). To lock the mesh (36), the mesh (36) is placed between perforation plate (34) and support ring (37). The three locking extensions (35) of perforation plate (34) and the three slits (38) of the support ring (37) are matched and the support ring (37) is rotated.
In this embodiment, the perforation plate (34) perforations area has a diameter of D1, mesh (36) has a diameter of D2, and support ring (37) has a diameter of D3. In this locking mechanism, the diameter of D1, D2, D3 of perforated plate (28), mesh (36) and support ring (37 ) are equal before and after fixing of the mesh (36).
In another embodiment of the present invention relates to a process to produce Carbon Nano tube (CNT) in a semi-continuous mode by the reactor (100, 100-1) wherein a catalyst is fed into the pre-heater zone (2) at atmospheric conditions through the manual catalyst feed section (1) which may include a ball valve or gate valve (1). The catalyst is fed into the pre-heater zone (2) to avoid the catalyst sintering and preventing the catalyst’s exposure from atmospheric conditions to high temperature above 600o C. The catalyst pre-heater zone (2) is operated in the temperature range of 200 o -400 o C. The catalyst is preheated in an inert atmosphere with inert gases like nitrogen or Argon or mixtures thereof. Further, the catalyst is preheated in an inert atmosphere for 2 hour to 18 hrs.
The preheated catalyst is fed from pre-heater zone (2) to the catalyst activation zone (5). with the opening of the Knife gate valve (4). The pre-heater zone is available for preheating the next batch of catalyst after evacuation of catalyst from the catalyst pre heater zone to catalyst activation zone. After preheated catalyst is loaded in the catalyst activation zone (5) from pre-heater zone (2), the knife gate valve (4) is closed. The temperature of catalyst activation zone (5) is maintained in the range between 400o C to 750o C. Hydrogen and Nitrogen mixture from inlet (6) is used for activation of the catalyst. The catalyst is activated for 4 to 18 hours. After activation in the catalyst activation zone (5), the activated catalyst is transferred to Carbon Nanotube Reactor zone (8A) comprising of comprising of Carbon Nano tube (CNT) growth zone (8) and Feed vaporizer zone (12) by opening of the knife gate valve (7). After activated catalyst is loaded in Carbon Nanotube Reactor zone (8A) from catalyst activation zone (5) the knife gate valve (7) is closed. The activation zone (5) is available for activation of next batch catalyst after evacuation of activated catalyst from activation zone (5) to Carbon Nanotube Reactor zone (8A).
The temperature of Carbon Nanotube Reactor zone (8A) is maintained in the range of 555o to 900o C. Simultaneously a preheated feed and nitrogen mixture into the feed vaporizer zone (12) continuously for 2 hours to 18 hours. This feed vapors are mixed with the activated catalyst in the Carbon Nanotube Reactor zone (8A) through the mesh (30, 36) of the Catalyst –Feed distributor plate (10, 27 ,33) for CNT growth. During the reaction, knife gate vale (7), (11) and (13) are in closed position. Any carry over CNT in the product stream is led out by the product gas out let (21) connected to the separator (22) to separate if any carry over CNT is present in the product stream in bottom of separator (22). The separated gaseous stream is sent for recycle or vented out in to the atmosphere. After completion of CNT growth zone (8) and feed vaporizer zone (12) are purged with nitrogen or inert gas to remove the traces of hydrogen present in the zones. After removing of hydrogen, the solid product CNT is evacuated by using of knife gate valves (11) and (13). The CNT reaction zone is available for reaction after evacuation of CNT from the reaction zone to the CNT cooling zone. During evacuation of the CNT, the evacuation stirrer (20) and a CNT reactor Piston (25) arrangement is used to remove the CNT and at same time the knife gate valve (11) and (13) is kept at an opened position. The evacuated CNT is collected in the cooling zone (14). The cooling zone (14) is cooled using of heat transfer fluid flow in the external jacketed heat exchanger (18) surrounding the cooling zone. Further, CNT is cooled inside by using nitrogen or inert gas purging (15). CNT is kept for cooling inside the cooling zone ranging from 2 hour to 8 hour. After cooling, CNT is collected in collection zone/vessel (17) by opening of Knife gate valve (16). The CNT reactor zone (8A) has over head evacuation stirrer (20) and a CNT reactor Piston (25) arrangement to avoid the CNT aggregate formation during reaction and also scraps the CNT from reactor walls to minimize the CNT loss. Piston valve arrangement (25) evacuates the CNT product from reactor after the end of reaction by moving the piston from top to bottom of reaction growth zone. The stirrer arrangement has the advantages of spreading the catalyst uniformly over the catalyst-feed distributor plate during catalyst loading, avoids the lump formation during the reaction and helps in CNT product movement from reaction zone to cooling zone. In the process of the CNT production the preheater zone (2), Activation zone (5), CNT growth zone (8) and Feed vaporizer zone (12), CNT cooling zone (14), Collection zone/vessel (17) cycle time maintained in the range of 2 hour to 18 hour.
One more detailed embodiment of the present invention deals with a reactor used for producing CNT in semi continuous mode using the feed as crude oil or its products such as Light naphtha, Clarrified oil, Blue oil, Light Cycle oil or C1-C5 gases such as methane, ethane, ethylene, propane, propylene, butane, butylenes and its isomers or mixtures thereof .
At any point of time, every zone of rector will be occupied with either catalyst or CNT with their respective reactions to improve the through put and consume less energy.
Example :1
The pre-weighed 140 gm of Co-Mn/Mgo (Magnesium oxide supported Cobalt, Manganese) catalyst is fed into the pre-heater with the use of manual valve. Before catalyst fed into the preheater, it was ensured the knife gate valve present in the bottom of the preheater is closed position. Preheater diameter is 0.1metre. The Catalyst preheater zone is maintained at a temperature of 400o C. The catalyst is preheated with inert atmosphere using nitrogen flow rate of 1.2 Litre per Minute (LPM). The catalyst is preheated up to 4 hours. The preheated catalyst transferred from catalyst preheater zone using the knife gate valve. Activation Zone diameter is 0.1m. After transferring the catalyst from preheater zone to Activation zone, the preheater knife gate valve is closed. The preheater zone is ready for preheating the second batch fresh catalyst. 140 gm of pre-weighed fresh catalyst is fed for preheating. The catalyst is activated with using of hydrogen along with nitrogen gas. The hydrogen flow rate is maintained at 2 LPM and nitrogen flow rate was maintained at 1.2 LPM. The activation of catalyst done for 4 hours. After 4 hours, the hydrogen flow is stopped, and the activated catalyst is transferred from activation zone to CNT reactor zone by opening of knife gate valve present at the bottom of the activation zone. After discharging the activated catalyst to reactor zone, the activation zone knife gate valve is closed. Simultaneously, the second batch preheated catalyst transferred is for activation. After activation the second batch catalyst maintained at inert atmosphere in the activation zone. Simultaneously, the preheater zone is ready for preheating the third batch fresh catalyst. The preheater zone is maintained at inert atmosphere by nitrogen flow at 1.2 LPM. Depending on the cycle time selected of CNT reactor zone, the other zones are also operated at same cycle time.
After feeding the activated catalyst to reactor zone, the catalyst was spread uniformly across the catalyst-feed distributor plate using magnetic stirrer operating for 5 minutes. The catalyst-feed distributor plate and mesh locking mechanism selected as shown in Figure: 4. The reactor zone diameter is 0.3m.The reactor zone temperature has maintained around 650 o C. Feed light naphtha(C5-95) is pumped through feed pump with the flow rate of 400 grams/hour and nitrogen flow rate is maintained between 2.5 LPM. The feed light naphtha and nitrogen preheated up to 250 o C and fed in to the feed vaporizer zone. The feed vaporizer zone temperature kept around 650o C. The magnetic stirrer operated for 15 minutes every 2 hours of reaction to break the CNT lumps. The reaction between the catalyst and naptha vapor kept around 12.5 hour in the reaction zone. The product gas which contains C2-C5 gases are sent through gaseous product outlet line and the composition analyzed by online Gas Chromatography.
After 12.5 hours of reaction the feed is stopped. The magnetic stirrer is operated for 10 minutes. Then the knife-gate valve present in the bottom of the reaction zone and feed vaporization zone simultaneously opened off and hot CNT transferred from reaction zone to cooling zone with gravity.
After evacuation, the reactor zone is ready for transfer of second batch activated catalyst from Activation zone .
After CNT evacuation above both knife gate valves closed. In cooling zone CNT is kept for 6 hours. After cooling CNT is evacuated from cooling zone to CNT collection zone/vessel. The amount of CNT collected and weighed in the weighing balance. Total amount of CNT collected is 1.96 Kg. Purity of CNT obtained as 94.13 % by Thermal gravimetric analysis(TGA). Transmission Electron Microscope analysis(TEM) and Raman Spectra given in Figure 6(a) and 6(b)Total material balance with nitrogen free basis is given in Table:1.
Table :1 Light Naphtha as feed stock
Total Mass Input (Kg) Total Mass out put
Light Naphtha 5 Hydrogen 0.29
Methane 1.2
C2-C5 gases 1.55
CNT 1.96

Feed (SR-Light naphtha) characterization
Feed Sulfur Nitrogen
ppmw ppmw
Light Naphtha 150 1.5

ASTM
D-86
(Volume%) IBP 5 10 20 30 40 50 60 70 80 90 95 FBP
C 35.5 47.5 50 56.5 62 66.5 72 77.5 83 89.5 98.5 ND 106

Table :1 (a) Thermal Gravimetric Analysis (TGA)
CNT Purity
% Weight. loss (Room Temperature to900°C) % Residue
94.13 5.87

Example :2(Methane as Feed stock)
The pre-weighed 140 gm of Fe-Mn/Mgo (Magnesium oxide supported Iron and Manganese) catalyst fed into the pre-heater with the use of manual valve. Before catalyst is fed into the preheater, it was ensured the knife gate valve present in the bottom of the preheater is closed position. Preheater diameter is 0.1metre. The Catalyst preheater zone is maintained at a temperature of 400o C. The catalyst is preheated with inert atmosphere using nitrogen flow rate of 1.2 Littre per Minute (LPM). The catalyst is preheated up to 4 hours. The preheated catalyst is transferred from catalyst preheater zone using the knife gate valve. Activation Zone diameter is 0.1m. After transferred the catalyst from preheater zone to Activation zone, the preheater Knife gate valve is closed. The preheater zone is ready for preheating the second batch fresh catalyst. 140 gm of pre-weighed fresh catalyst is fed for preheating. The catalyst is activated with using of hydrogen along with nitrogen gas. The hydrogen flow rate is maintained at 2 LPM and nitrogen flow rate was maintained at 1.2 LPM. The activation of catalyst done for 4 hours. After 4 hours, the hydrogen flow is stopped, and the activated catalyst transferred from activation zone to CNT reactor zone using of knife gate valve present at the bottom of the activation zone. After discharging the activated catalyst to reactor zone, the activation zone knife gate valve is closed. Simultaneously the second batch preheated catalyst transferred for activation. After activation the second batch catalyst maintained at inert atmosphere in the activation zone. Simultaneously the preheater is ready for preheating the third batch fresh catalyst. The preheater zone is maintained at inert atmosphere by nitrogen flow at 1.2 LPM. Depending on the cycle time selected of CNT reactor zone, the other zones also operated at same cycle time.
After feed the activated catalyst to reactor zone (CNT growth zone), the catalyst was spread uniformly across the catalyst-feed distributor plate using magnetic stirrer operating for 5 minutes. The catalyst-feed distributor plate and mesh locking mechanism selected as shown in Figure: 4. The reactor zone diameter is 0.3m.The reactor zone (CNT growth zone) temperature has maintained around 650o C. Light naphtha flow rate is maintained 400 grams/hour and nitrogen flow rate is maintained between 2.5 LPM. The feed light naphtha and nitrogen is preheated up to 300o C and fed in to the feed vaporizer zone. The feed vaporizer zone temperature kept around 700o C. The magnetic stirrer operated for 15 minutes every 2 hours of reaction to break the CNT lumps. The reaction between the catalyst and naptha vapor kept around 12.5 hour in the reaction zone. The product gas which contains C2-C5 gases are sent through gaseous product outlet line and the composition analyzed by online Gas Chromatography.
After 12.5 hours of reaction the feed is stopped. The magnetic stirrer is operated for 10 minutes. Then the knife-gate valve present in the bottom of the reaction zone and feed vaporization zone simultaneously opened off and hot CNT transferred from reaction zone to cooling zone with gravity.
After evacuation, the reactor zone is ready for transfer of second batch activated catalyst from Activation zone .
After CNT evacuation above both knife gate valves closed. In cooling zone CNT is kept for 6 hours. After cooling CNT is evacuated from cooling zone to CNT collection zone/vessel. The amount of CNT collected and weighed in the weighing balance. Total amount of CNT collected is 1.71 Kg. Total material balance with nitrogen free basis is given in Table:2.
Table :2 Methane as feed stock
Total Mass Input (Kg) Total Mass output(Kg)
Methane 5 Hydrogen 0.23
Methane 3.06
CNT 1.71

Example :3
The pre-weighed 140 gm of Co-Mn/Mgo (Magnesium oxide supported Cobalt, Manganese) catalyst is fed into the pre-heater with the use of manual valve. Before catalyst is fed into the preheater, it was ensured the knife gate valve present in the bottom of the preheater is closed position. Preheater diameter is 0.1metre. The Catalyst preheater zone is maintained at a temperature of 400o C. The catalyst is preheated with inert atmosphere using nitrogen flow rate of 1.2 Littre per Minute (LPM). The catalyst is preheated up to 4 hours. The preheated catalyst transferred from catalyst preheater zone using the knife gate valve. Activation Zone diameter is 0.1m. After transferred the catalyst from preheater zone to Activation zone, the preheater Knife gate valve is closed. The preheater zone is ready for preheating the second batch fresh catalyst. 140 gm of pre-weighed fresh catalyst is fed for preheating. The catalyst is activated with using of hydrogen along with nitrogen gas. The hydrogen flow rate is maintained at 2 LPM and nitrogen flow rate was maintained at 1.2 LPM. The activation of catalyst done for 4 hours. After 4 hours, the hydrogen flow is stopped, and the activated catalyst transferred from activation zone to CNT reactor zone using of knife gate valve present at the bottom of the activation zone. After discharging the activated catalyst to reactor zone, the activation zone knife gate valve is closed. Simultaneously, the second batch preheated catalyst transferred for activation. After activation the second batch catalyst maintained at inert atmosphere in the activation zone. Simultaneously, the preheater is ready for preheating the third batch of fresh catalyst. The preheater zone is maintained at inert atmosphere by nitrogen flow at 1.2 LPM. Depending on the cycle time selected of CNT reactor zone, the other zones also operated at same cycle time.
After fed the activated catalyst to reactor zone, the catalyst was spread uniformly across the catalyst-feed distributor plate using magnetic stirrer operating for 5 minutes. The catalyst-feed distributor plate and mesh locking mechanism selected as shown in Figure: 3. The catalyst-feed distributor plate and mesh locking mechanism selected as shown in Figure:3.The reactor zone diameter is 0.3m.The reactor zone temperature has maintained around 650o C. Feed light naphtha(C5-95) is pumped through feed pump with the flow rate of 400 grams/hour and nitrogen flow rate is maintained between 4 LPM. The feed light naphtha and nitrogen preheated up to 300o C and fed in to the feed vaporizer zone. The feed vaporizer zone temperature kept around 650o C. The magnetic stirrer operated for 15 minutes every 2 hours of reaction to break the CNT lumps. The reaction between the catalyst and naptha vapor kept around 12 hour in the reaction zone. The product gas which contains C2-C5 gases are sent through gaseous product outlet line and the composition analyzed by online Gas Chromatography.
After 15 hours of reaction the feed is stopped. The magnetic stirrer is operated for 10 minutes. Then the knife-gate valve present in the bottom of the reaction zone and feed vaporization zone simultaneously opened off and hot CNT transferred from reaction zone to cooling zone with gravity.
After evacuation, the reactor zone is ready for transfer of second batch activated catalyst from Activation zone .
After CNT evacuation above both knife gate valves closed. In cooling zone CNT is kept for 6 hours. After cooling CNT is evacuated from cooling zone to CNT collection zone/vessel. The amount of CNT collected and weighed in the weighing balance. Total amount of CNT collected is 2.93 Kg. Purity of CNT is 95.43%.Total material balance with nitrogen free basis is given in Table: 3
Table :3 Light Naphtha as feed stock
Total Mass Input (Kg) Total Mass output(Kg)
Light Naphtha 4.8 Hydrogen 0.43
Methane 0.83
C2-C5 gases 0.61
CNT 2.93

ADVANTAGES OF THE INVENTION:
• Semi continuous reactor which comprises the catalyst preheating zone , catalyst activation zone, reaction zone which further comprises CNT growth zone and feed vaporizer zone ,CNT cooling zone and CNT evacuation Zone which produce CNT in semi continuous mode and there is no need of cooling the reactor for CNT evacuation with less metal impurity.
• Catalyst sintering avoided by using of catalyst preheater zone and avoiding direct exposure of high temperature
• Overhead stirrer/Piston arrangement for uniform spreading of catalyst over catalyst-feed distributor plate, high yield CNT and also used for breaking the CNT lumps to easy evacuation CNT from reactor
• Knife gate valve in each zone to isolate the individual reaction zone
• Knife gate valve supported movable catalyst-feed distributor plate for CNT growth for easy removable of catalyst supporting mesh and replacement of mesh without opening the reactor
• Locking mechanism of perforated plate, mesh and a support ring allows the easy maintenance of distributor and replacement of worn out mesh without opening of the reactor.
• Simultaneously each zone operating different process conditions
• At any point of time, every zone of reactor will be occupied with either catalyst or CNT with their respective reactions to improve the through put and consume less energy.
• Continuous pre-heating and activation zone for the catalyst
• Reactor for both liquid or gaseous feed stocks or mixtures
, Claims:1. A reactor (100, 100-1) for producing Carbon Nano tube (CNT) in semi-continuous mode comprising;
a) a manual catalyst feed section (1) adapted to feed the catalyst into the reactor;
b) a catalyst preheating zone (2) adapted for continuous preheating of the catalyst;
d) a catalyst activation zone (5) adapted for continuous activation of the catalyst;
e) a Carbon Nano tube (CNT) reaction zone (8A) adapted to facilitates the reaction between a feed mixture and the activated catalyst, which further comprises of;
(i) a Carbon Nano tube (CNT) growth zone (8) adapted to facilitates the reaction between the feed mixture and the catalyst wherein the feed mixture is catalytically decomposed, and CNT is grown on the catalyst in presence of an inert atmosphere ;
(ii) a Feed vaporizer zone (12) adapted for vaporisation of the feed, wherein the feed vapor mixture containing an inert gas that enters from feed vaporization zone (12) to the Carbon Nano tube (CNT) growth zone for catalyst reaction;
f) a Carbon Nano tube (CNT) cooling zone (14) adapted to cool the produced CNT; and
g) a Carbon Nano tube (CNT) collection zone/vessel (17) adapted to collect the produced Carbon Nano tube (CNT);
wherein the zones of the reactor comprise a plurality of knife gate valves adapted to isolate individual zones.
2. The reactor (100, 100-1) as claimed in claim 1, wherein the knife gate valves are closed during the reaction in different zones
3. The reactor (100, 100-1) as claimed in claim 1, wherein the Carbon Nano tube (CNT) growth zone (8) and feed vaporization zone (12) are separated by a knife gate valve (11).
3. The reactor (100, 100-1) as claimed in claim 3, wherein the knife gate valve (11) comprises of a catalyst-feed distributor plate (10, 27, 36) adapted to hold the activated catalyst .
4. The reactor (100, 100-1) as claimed in claim 3, wherein the catalyst-feed distributor plate (10, 27, 36) comprises of a perforation plate (28, 34), a mesh (30, 36) adapted to hold the activated catalyst and a support ring (32, 37), wherein the catalyst–feed distributor plate (10, 27, 36) is adapted for removal and replacement of the mesh (30, 36).
5. The reactor (100, 100-1) as claimed in claim 4, wherein size of the mesh (30, 36) is in the range of 10 microns to 50 microns.
6. The reactor (100, 100-1) as claimed in claim 4, wherein the perforated plate (28, 34) and support ring (32, 37) are sandwiched to hold the mesh (30, 36) through a plurality of locking mechanisms.
7. The reactor (100, 100-1) as claimed in claim 5, wherein the perforated plate (34) and support ring (37) are sandwiched to hold the mesh (36) through lock and rotate mechanism wherein an outside diameters D1, D2, D3 of the perforated plate (D1), mesh (D2) and support ring (D3) (37) are equal before and after fixing of the mesh (36).
8. The reactor (100, 100-1) as claimed in claim 5, wherein the perforated plate (28) and the support ring (32) are sandwiched to hold the mesh (30) through lock and rotate mechanism wherein a slot on the perforated plate (28) with an inner diameter D2 is equal to inner diameter D4 of the support ring (32) and outer diameter D1 of the perforated plate (28) is equal to outer diameter D3 of the mesh (30).
9. The reactor (100, 100-1) as claimed in claim 1 wherein CNT growth zone comprises of a stirrer (9) adapted to agitate the activated catalyst to spread.
10. The reactor (100, 100-1) as claimed in claim 1, wherein CNT growth zone comprises a piston (25) adapted to uniformly disperse catalyst across the catalyst–feed distributor plate (10).
11. The reactor (100, 100-1) as claimed in claim 1, wherein the cooling zone (14) contains nitrogen purging inside the cooling zone by inlet (15) and an external jacketed heat exchanger (18) to cool the CNT.
12. The reactor (100, 100-1) as claimed in claim 1,wheren a product gas outlet is connected to a separator (22) to separate any carry over CNT in the product stream in bottom of the separator (22).
13. A process to produce Carbon Nano tube (CNT) in a semi-continuous mode by the reactor (100, 100-1) as claimed in claim 1, comprising the following steps;
- Feeding a catalyst into the pre-heater zone (4) through the manual catalyst feed section (1) at atmospheric conditions;
- Preheating the catalyst in the catalyst preheater zone (4) at a temperature of 200o-400 o C in an inert atmosphere for 4 to 18 hours;
- Feeding the preheated catalyst from the catalyst preheater zone (4) to the catalyst activation zone (5) by opening a knife gate valve (4) of the catalyst pre-heater zone (4);
- Closing the knife gate valve (4) of the catalyst pre-heater zone;
- Heating the catalyst activation zone (5) to maintain a temperature in the range of 400 o C to 750 o C;
- Activating the catalyst in the catalyst activation zone (5) for 4 to 18 hour by mixing hydrogen and nitrogen gas mixture from an inlet (6);
- Transferring the activated catalyst from the catalyst activation zone (5) to the Carbon Nano tube (CNT) reaction zone (8) by opening a knife gate valve (7) at the bottom of the catalyst activation zone (5);
- Closing the knife gate valve (7) of the catalyst activation zone (5) after transferring the activated catalyst to the Carbon Nano tube (CNT) reaction zone (8);
- Heating the Carbon Nano tube (CNT) growth zone (8) of the Carbon Nano tube (CNT) reaction zone (8) to maintain a temperature in the range of 550o-900o C
- Feeding a preheated feed and nitrogen mixture into the feed vaporizer zone (12) continuously for 2 hours to 18 hours;
- Heating the feed vaporizer zone to maintain a temperature in the range of 550 o to 900 o C;
- Mixing the feed vapors from the feed vaporization zone (12) through the mesh (30, 36) of the Catalyst –Feed distributor plate (10, 27, 36) with the activated catalyst in the Carbon Nano tube (CNT) growth zone (8) for CNT growth;
- Purging the CNT growth zone (8) and feed vaporizer zone (12) with nitrogen or inert gas to remove the traces of hydrogen present in the CNT growth zone (8) and feed vaporizer zone (12);
- Stirring the activated catalyst uniformly by the evacuation stirrer (20) and a CNT reactor Piston (25) arrangement over the Catalyst –Feed distributor plate (10, 27, 36) and breaking the CNT lumps;
- Evacuating the produced CNT from (CNT) growth zone (8) and feed vaporization zone (12) to the cooling zone (14) by opening a knife gate valve (11) at the bottom of the (CNT) growth zone (8) and a knife gate valve (13) at the feed vaporization zone (12);
- Cooling the produced CNT in the cooling zone (14) using nitrogen or inert gas from inlet (15) and external jacketed heat exchanger (18) for 2 hour to 8 hour;
- Collecting CNT in the collection vessel (17) by opening a knife gate valve (16) at the bottom of the cooling zone (14).
14. The process to producing Carbon Nano tube (CNT) as claimed in claim 13, wherein the feed is selected from crude oil, its products or C1-C5 gases such as methane, ethane, ethylene, propane, propylene, butane, butylenes and its isomers or mixture thereof.
15. The process to producing Carbon Nano tube (CNT) as claimed in claim 13, wherein the knife gate valve (11) of Carbon Nano Tube growth zone (8), the knife gate valve (7) of Catalyst activation zone (5) and knife gate valve (13) of feed vaporization zone (12) are in closed position during the reaction of the activated catalyst and feed vapors in the Carbon Nano tube (CNT) reaction zone (8A).
16. The process to producing Carbon Nano tube (CNT) as claimed in claim 13, wherein the process time of each zone is 2 hour to 18 hour.