Title of Invention	"NOVEL DISTRIBUTOR TRAY FOR TRICKLE BED REACTOR"
Abstract	The present invention relates to a novel distributor tray (1) for distributing down flowing vapour or gas and liquid on catalyst beds in trickle bed reactors. The distributor tray (1) consists of distributor units (7) and each distributor unit (7) consists of a gas tube (9) a liquid tube (10) and a secondary distribution attachment (11). The apparatus distributes gas and liquid through primary distribution points and subsequently distributes the liquid further through its secondary distribution attachment. This distributor tray (1) offers high density of primary distribution points, provides good quality secondary distribution of liquid operates at high turndown ratio and is resistant to fouling.

Title of Invention

"NOVEL DISTRIBUTOR TRAY FOR TRICKLE BED REACTOR"

Abstract

The present invention relates to a novel distributor tray (1) for distributing down flowing vapour or gas and liquid on catalyst beds in trickle bed reactors. The distributor tray (1) consists of distributor units (7) and each distributor unit (7) consists of a gas tube (9) a liquid tube (10) and a secondary distribution attachment (11). The apparatus distributes gas and liquid through primary distribution points and subsequently distributes the liquid further through its secondary distribution attachment. This distributor tray (1) offers high density of primary distribution points, provides good quality secondary distribution of liquid operates at high turndown ratio and is resistant to fouling.

Full Text	NOVEL DISTRIBUTOR TRAY FOR TRICKLE BED REACTOR FIELD OF INVENTION The present invention relates to a novel distributor tray for distribution of down flowing vapour or gas and liquid on a bed of catalyst particles in a trickle bed reactor. The novel distributor tray for trickle bed reactor, offers high density of primary distribution points, provides good quality secondary distribution of liquid operates at high turndown ratio and is resistant to fouling. PRIOR ART AND BACKGROUND OF INVENTION Trickle bed reactor consists of a fixed bed of solid catalyst particles contacted by a co current downward gas-liquid flow carrying both reactants and products (Figure 1). Trickle bed reactors are widely used in the petroleum industry in various applications such as hydroteating, hydrocracking, hydrorefming, etc. The distributor tray located above the catalyst bed is used to distribute liquid and gas uniformly. The catalyst particles are always porous, are in the form of extrudates, granules, spheres, tablets. The liquid flows down the reactor from particle to particle on the surface of the catalyst while the gas phase travels in the remaining void space of the flow channels. In general, the reaction occurs between the dissolved gas and liquid phase reactant at the interior surface of the catalyst. The performance of the reactor is affected by fluid distribution mainly liquid, liquid holdup, back mixing, catalyst wetting, mass and heat transfer phenomena. Several designs of distributor trays are commercially available: (1) Perforated tray/Sieve tray type distributors- These are the earliest type of distribution trays used in the trickle bed reactors. They consist of a perforated tray or sieve tray with gas chimneys. This tray is simple to construct and is capable of providing the greatest number of drip points over the cross section of the catalyst bed. (2) Chimney type distributors- These designs have chimneys evenly spaced across the distribution tray. These chimneys allow the vapor to pass through the top opening. The liquid flow is distributed through weep holes or notches cut into the side of riser. This design eliminates the sensitivity to plugging. This type of device is essentially equivalent to a perforated tray with elevated liquid ports. A further improvement of this simple chimney distributor is the multi-port chimney. This distributor design has weep holes spaced vertically up the axis of the chimney, which provide greater flexibility to changing vapour/liquid ratios. These have increased tolerance to tray levelness problems. (3) Bubble-cap type distributors - Bubble-cap design operates on a vapour assisted principle compared to liquid overflow principle employed in the chimney type distributors. In this design, vapour passing through slots in the bubble cap aspirate liquid held up on the tray, carrying it over a central down comer. The bubble cap design is much less sensitive to tray levelness than others because the liquid on tray is carried by the vapour. It is also less sensitive over a broad range of liquid loading. Another advantage of this type of distributor is that it acts like an additional quenching device, bringing the liquid and vapour closer to an equilibrium temperature before they enter the catalyst bed. Also this is less prone to fouling compared to chimney type distributor. (4) Vapour-lift Distributor- These distributors incorporate all advantages like vapour- liquid mixing, low vulnerability to plugging normally associated with vapour assist distributor such as bubble-cap distributor tray. But this tray has much smaller diameter chimney, which enables the installation of more distribution points across the tray area. These distributors exhibit very stable, low sensitivity operation over a broad range of the vapour/liquid ratios. Drawbacks connected with hitherto Known Processes/Devices: A number of problems are encountered in the use of these known distributing devices. Perforated tray type distributors have high sensitivity to tray levelness. The perforations can easily be plugged by coke, corrosion products or other particles carried into the reactor by the feed. Also in this type of device, the flexibility to liquid load is very poor. Another disadvantage of this device is that it can be designed to give good performance at either the design conditions or at turndown conditions, but not at both situations. Therefore, the tray has a tendency to run dry as vaporization increases towards the end of the cycle. Therefore, this type of device is not expected to provide good distribution. In chimney type distributors, the liquid flow is governed by the overflow principle. This design is also very sensitive to the tray levelness and changes in liquid loading. It offers fewer drip points than the perforated tray. To provide the turndown capability, these distributors are designed to maintain a liquid level at the design conditions above the level of the weep holes or notch bottom. If the feed rate is increased or a heavier feed is processed, the level on the tray will increase and can flood over the top of the chimney. The main disadvantage of bubble cap type distributor is that it requires large diameter and thus less number of drip points on to the catalyst bed. Vapour-lift design is basically a vapour assist distributor like bubble cap distributor and vapour assist distributor; in general have the problem of non-uniform secondary distribution. The present invention discloses a novel design of distributor tray for trickle bed reactor, which offers high density of primary distribution points, provides good quality secondary distribution of liquid, operates at high turndown ratio and is resistant to fouling. OBJECTS OF THE INVENTION The main objective of the invention is to provide a novel design for distributor tray for use in trickle bed reactors. Another object of the present invention is to provide a novel distributor tray having large number of distribution points. Still another object of the present invention is to provide a novel distributor tray having higher density of distribution points which improves performance of the catalyst bed due to better wetting of catalyst particles. Yet another object of the present invention is to provide a novel distributor tray to provide secondary distribution of liquid. Another object of the present invention is to provide novel distributor tray which is resistant to fouling and reduces maintenance requirements. SUMMARY OF THE INVENTION The present invention discloses an apparatus for distribution of down flowing vapour or gas and liquid on a bed of catalyst particles in a trickle bed reactor comprising of a distributor tray on which a number of distributor units are located. In another embodiment of the present invention the vapour or gas and liquid are fed to the distributor tray through a feed pipe and an inlet device attached to the feed pipe wherein the vapour or gas is distributed over the catalyst bed through primary distribution points and the liquid is first distributed through the primary distribution points and then further distribution of liquid is achieved through the secondary distribution attachments. In still another embodiment of the present invention each distributor unit consists of a gas tube, a liquid tube and a secondary distribution attachment wherein the gas tube offers passage to vapour or gas and the liquid tube offers independent passage to the liquid. In yet another embodiment of the present invention the vapour or gas enters the gas tube through a number of rectangular slots wherein these slots are dimensioned to provide sufficient pressure drop in the gas phase to ensure uniform distribution of vapour or gas and the liquid enters the gas tube from the liquid tube through a number of circular holes wherein the vapour or gas velocity in the gas tube imparts enough energy on the liquid to ensure further distribution of liquid phase. In another embodiment of the present invention the liquid enters the liquid tube through specified numbers of circular holes located at different elevations which ensures uniform distribution even under turndown conditions wherein the holes on the liquid tube are located above the distributor tray deck level, which offers high level of resistance to fouling. In yet another embodiment of the present invention the secondary distribution attachment provides further distribution of liquid with or without the aid of vapour or gas velocity wherein at high vapour or gas velocity, the vapour or gas assists secondary distribution of liquid and the attachment helps in achieving uniformity of the distribution, which otherwise is quite non-uniform and at low vapour or gas velocity, when the vapour or gas hardly provides any assistance to liquid distribution, the attachment provides excellent secondary distribution of liquid. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS Figure-1: Configuration of trickle bed reactor where the location of the distributor tray (1) is shown relative to catalyst bed and other reactor internals. Figure-2: Assembly of the distributor tray inside a reactor and orientation of primary distribution points. Figure-3: Details of a distributor unit (7). Figure-4: Details of the vapour/gas tube (9). Figure-5: Details of the liquid tube (10). Figure-6: Details of secondary distribution attachment (11). DESCRIPTION OF THE INVENTION Gas/ liquid two-phase distributor tray is an integral part of trickle bed reactor. In a trickle bed reactor gas and liquid flow downward co-currently through catalyst beds. Performance of catalyst in facilitating desired reactions depends largely on the efficiency of the distributor tray. Following aspects are important for designing the two-phase distributor tray: Primary distribution of liquid and gas Secondary distribution of liquid - Turndown of gas and liquid rates Resistance to fouling Catalyst used in trickle bed reactors are typically of lmm-3mm size. Such small sized particles have limited capability for radial distribution of liquid. Therefore, for such particles, higher density of distribution points improves performance of the catalyst bed due to better wetting of catalyst particles. Therefore, in addition to primary distribution of liquid through large number of distribution points, the distributor tray is also designed to provide secondary distribution of liquid. As far as distribution of gas phase is concerned, initial distribution through large number of distribution is important. Further distribution of gas is achieved due to high-pressure drop across catalyst bed. To economize the design and engineering as well to fulfill the process requirement high turndown distributors are important. Resistance to fouling offers wider range of applicability reduces maintenance requirements. The present invention proposes a novel design for distributor tray for use in trickle bed reactors. The novel design of the distributor tray offers high density of primary distribution points, good quality secondary distribution of liquid, high turndown of gas and liquid rates and effective resistance to fouling. The following embodiments are provided to illustrate the invention is accordance with the principle of the invention, but are not construed as limiting the invention in any way except as indicated in the appended claims. Figure-1 shows the overall assembly of the distributor tray (1). The distributor (1) is installed in a reactor (2), above a bed (3) of catalyst particles. During normal operation, gas and liquid enter the reactor through the inlet (4) and flows co currently downward through the distributor (1) and the catalyst bed (3) to the outlet (5). Inside the reactor (2), the distributor (1) is supported on a support ring (6) and the support ring is welded to the inside wall of the reactor (2). The overall assembly of the distribution tray (1) inside a reactor and orientation of primary distribution points is shown in Figure-2. The distributor tray consists of a number of distributor units (7) located on the tray (1). Each distributor unit corresponds to a primary distribution point (8). The number and orientation of primary distribution points (8) depend on design conditions of the distributor tray (1). The details of a distributor unit are shown in Figure-3. The distributor unit (7) consists of a gas tube (9), a liquid tube (10) and a secondary distribution attachment (11). The gas tube (9) passes through the primary distribution point (8) and welded to the lower surface of the distributor tray (1). The secondary distribution attachment (11) is welded to the bottom part of the gas tube (9). The liquid tube (10) is concentric and placed outside the gas tube (9). The liquid tube is welded on the upper surface of the distributor tray. The details of the vapour/gas tube (9) are shown in Figure-4. It consists of a pipe (12), closed from top and open from bottom. Specified number of rectangular slots (13) are there at the top part of pipe for entry of vapour or gas. Specified number of rectangular slots (14) are also present at the bottom edge of the pipe (12) for vapor or gas exit. Specified numbers of circular holes (15) are there just above the distributor tray (1) location for entry of liquid from liquid tube (10) to gas tube (9). A circular cover plate (16) is welded to the pipe (12) just below the top slots (13), which acts as cover for the liquid tube (10). The details of liquid tube (10) are shown in Figure-5. It consists of a pipe (17) placed concentrically around the gas tube (9) and the annular gap between them is maintained by specified numbers of stoppers (18). The pipe (17) has specified numbers of circular holes (19) at two levels above the location of the distributor tray (1). Liquid from the distributor tray (1) enters into the pipe (17) through these holes (19). The secondary distribution attachment (11) provides further distribution of liquid. The details of secondary distribution attachment (11) are shown in Figure-6. It consists of a slotted plate (20). Two concentric rings (21 & 22) with serrated bottom are welded to the bottom surface of the slotted plate (20). Specified numbers of vertical baffles (23) are welded to the top surface of the slotted plate (20). The slotted plate (20) has a circular hole (24) at the center. The vertical baffles (23) are so oriented that on welding the secondary distribution attachment (11) to the bottom end of the gas tube (9), the baffles (23) are located at the center of the bottom slots (14). The main advantages of the present invention are: 1. The distributor tray of the present invention has large number of distribution points which improves performance of the catalyst bed due to better wetting of catalyst particles. 2. In the present invention the liquid is first distributed through the primary distribution points and then further distribution of liquid is achieved through the secondary distribution attachments. The secondary distribution attachments provide further distribution of liquid with or without the aid of vapour or gas velocity. 3. At high vapour or gas velocity, the vapour or gas assists secondary distribution of liquid and the secondary distribution attachment helps in achieving uniformity of the distribution, which otherwise quite non-uniform. 4. At low vapour or gas velocity, when the vapour or gas hardly provides any assistance to liquid distribution, the attachment provides excellent secondary distribution of liquid. 5. The distributor tray of the present invention is resistant to fouling and reduces maintenance requirements. 6. The novel distributor tray of the present invention ensures uniform distribution of vapor or gas and liquid even under turndown conditions. 7. In the present invention at very high liquid load, the liquid overflows into the annular space between the gas tube and the liquid tube without disturbing the gas flow pattern. We claim: 1. An apparatus for distributing down flowing vapour or gas and liquid on a catalyst bed (3) in a trickle bed reactor comprising: (a) a distributor tray (1) consisting of distributor units (7) wherein each distributor unit (7) corresponds to a primary distribution point (8); and (b) each distributor unit (7) consists of a gas tube (9) a liquid tube (10) and a secondary distribution attachment (11). 2. The apparatus as claimed in claim 1 wherein said distributor tray (1) is connected to feed pipe (4) through an inlet device for vapour or gas and liquid entry. 3. The apparatus as claimed in any preceding claim wherein said gas tube (9) is connected to the lower surface of the distributor tray (1) and passes through said primary distribution point (8). 4. The apparatus as claimed in any preceding claim wherein said secondary distribution attachment (11) is connected to the bottom part of the gas tube (9). 5. The apparatus as claimed in any preceding claim wherein said liquid tube (10) is concentric and is connected on the upper surface of the distributor tray (1) and placed outside the gas tube (9). 6. The apparatus as claimed in any preceding claim wherein said gas tube (9) consists of a pipe (12), closed from top and open from bottom wherein said pipe (12) comprises: (a) rectangular slots (13) at the top part of said pipe (12) for vapour or gas entry; (b) rectangular slots (14) at the bottom edge of the pipe (12) for vapor or gas exit; (c) circular holes (15) above the distributor tray (1) for liquid entry from liquid tube (10) to gas tube (9); and (d) a circular cover plate (16) connected to said pipe (12) below said rectangular slots (13) which acts as cover for the liquid tube (10). 7. The apparatus as claimed in any preceding claim wherein said liquid tube (10) comprises a pipe (17), placed concentrically around the gas tube (9) and the annular gap between said liquid tube (10) and said gas tube (9) is maintained by stoppers (18) and said pipe (17) further consists of circular holes (19) at two levels above the distributor tray (1) for liquid entry from said distributor tray (1) into said pipe (17) through said circular holes (19). 8. The apparatus as claimed in any preceding claim wherein said secondary distribution attachment (11) provides further distribution of liquid and consists of: (a) a slotted plate (20) with a circular hole (24) at the center; (b) two concentric rings (21 and 22) with serrated bottom connected to the bottom surface of said slotted plate (20); and (c) vertical baffles (23) connected to the top surface of said slotted plate (20). 9. The apparatus as claimed in claim 8 wherein said vertical baffles (23) are located at the center of the rectangular slots (14). 10. An apparatus for distributing down flowing vapour or gas and liquid on a catalyst bed in a trickle bed reactor substantially as hereinbefore described and with reference to the accompanying drawings.

Full Text

NOVEL DISTRIBUTOR TRAY FOR TRICKLE BED REACTOR FIELD OF INVENTION
The present invention relates to a novel distributor tray for distribution of down flowing vapour or gas and liquid on a bed of catalyst particles in a trickle bed reactor. The novel distributor tray for trickle bed reactor, offers high density of primary distribution points, provides good quality secondary distribution of liquid operates at high turndown ratio and is resistant to fouling. PRIOR ART AND BACKGROUND OF INVENTION
Trickle bed reactor consists of a fixed bed of solid catalyst particles contacted by a co current downward gas-liquid flow carrying both reactants and products (Figure 1). Trickle bed reactors are widely used in the petroleum industry in various applications such as hydroteating, hydrocracking, hydrorefming, etc.
The distributor tray located above the catalyst bed is used to distribute liquid and gas uniformly. The catalyst particles are always porous, are in the form of extrudates, granules, spheres, tablets. The liquid flows down the reactor from particle to particle on the surface of the catalyst while the gas phase travels in the remaining void space of the flow channels. In general, the reaction occurs between the dissolved gas and liquid phase reactant at the interior surface of the catalyst. The performance of the reactor is affected by fluid distribution mainly liquid, liquid holdup, back mixing, catalyst wetting, mass and heat transfer phenomena.
Several designs of distributor trays are commercially available:
(1) Perforated tray/Sieve tray type distributors- These are the earliest type of
distribution trays used in the trickle bed reactors. They consist of a perforated tray
or sieve tray with gas chimneys. This tray is simple to construct and is capable of
providing the greatest number of drip points over the cross section of the catalyst
bed.
(2) Chimney type distributors- These designs have chimneys evenly spaced across the
distribution tray. These chimneys allow the vapor to pass through the top opening.
The liquid flow is distributed through weep holes or notches cut into the side of
riser. This design eliminates the sensitivity to plugging. This type of device is
essentially equivalent to a perforated tray with elevated liquid ports. A further
improvement of this simple chimney distributor is the multi-port chimney. This
distributor design has weep holes spaced vertically up the axis of the chimney,

which provide greater flexibility to changing vapour/liquid ratios. These have increased tolerance to tray levelness problems.
(3) Bubble-cap type distributors - Bubble-cap design operates on a vapour assisted
principle compared to liquid overflow principle employed in the chimney type
distributors. In this design, vapour passing through slots in the bubble cap aspirate
liquid held up on the tray, carrying it over a central down comer. The bubble cap
design is much less sensitive to tray levelness than others because the liquid on
tray is carried by the vapour. It is also less sensitive over a broad range of liquid
loading. Another advantage of this type of distributor is that it acts like an
additional quenching device, bringing the liquid and vapour closer to an
equilibrium temperature before they enter the catalyst bed. Also this is less prone
to fouling compared to chimney type distributor.
(4) Vapour-lift Distributor- These distributors incorporate all advantages like vapour-
liquid mixing, low vulnerability to plugging normally associated with vapour assist
distributor such as bubble-cap distributor tray. But this tray has much smaller
diameter chimney, which enables the installation of more distribution points across
the tray area. These distributors exhibit very stable, low sensitivity operation over a
broad range of the vapour/liquid ratios.
Drawbacks connected with hitherto Known Processes/Devices: A number of problems are encountered in the use of these known distributing devices. Perforated tray type distributors have high sensitivity to tray levelness. The perforations can easily be plugged by coke, corrosion products or other particles carried into the reactor by the feed. Also in this type of device, the flexibility to liquid load is very poor. Another disadvantage of this device is that it can be designed to give good performance at either the design conditions or at turndown conditions, but not at both situations. Therefore, the tray has a tendency to run dry as vaporization increases towards the end of the cycle. Therefore, this type of device is not expected to provide good distribution.
In chimney type distributors, the liquid flow is governed by the overflow principle. This design is also very sensitive to the tray levelness and changes in liquid loading. It offers fewer drip points than the perforated tray. To provide the turndown capability, these distributors are designed to maintain a liquid level at the design conditions above the level of the weep holes or notch bottom. If the feed rate is increased or a heavier feed is processed, the level on the tray will increase and can flood over the top of the chimney.

The main disadvantage of bubble cap type distributor is that it requires large diameter and thus less number of drip points on to the catalyst bed. Vapour-lift design is basically a vapour assist distributor like bubble cap distributor and vapour assist distributor; in general have the problem of non-uniform secondary distribution.
The present invention discloses a novel design of distributor tray for trickle bed reactor, which offers high density of primary distribution points, provides good quality secondary distribution of liquid, operates at high turndown ratio and is resistant to fouling. OBJECTS OF THE INVENTION
The main objective of the invention is to provide a novel design for distributor tray for use in trickle bed reactors.
Another object of the present invention is to provide a novel distributor tray having large number of distribution points.
Still another object of the present invention is to provide a novel distributor tray having higher density of distribution points which improves performance of the catalyst bed due to better wetting of catalyst particles.
Yet another object of the present invention is to provide a novel distributor tray to provide secondary distribution of liquid.
Another object of the present invention is to provide novel distributor tray which is resistant to fouling and reduces maintenance requirements. SUMMARY OF THE INVENTION
The present invention discloses an apparatus for distribution of down flowing vapour or gas and liquid on a bed of catalyst particles in a trickle bed reactor comprising of a distributor tray on which a number of distributor units are located.
In another embodiment of the present invention the vapour or gas and liquid are fed to the distributor tray through a feed pipe and an inlet device attached to the feed pipe wherein the vapour or gas is distributed over the catalyst bed through primary distribution points and the liquid is first distributed through the primary distribution points and then further distribution of liquid is achieved through the secondary distribution attachments.
In still another embodiment of the present invention each distributor unit consists of a gas tube, a liquid tube and a secondary distribution attachment wherein the gas tube offers passage to vapour or gas and the liquid tube offers independent passage to the liquid.
In yet another embodiment of the present invention the vapour or gas enters the gas tube through a number of rectangular slots wherein these slots are dimensioned to provide

sufficient pressure drop in the gas phase to ensure uniform distribution of vapour or gas and the liquid enters the gas tube from the liquid tube through a number of circular holes wherein the vapour or gas velocity in the gas tube imparts enough energy on the liquid to ensure further distribution of liquid phase.
In another embodiment of the present invention the liquid enters the liquid tube through specified numbers of circular holes located at different elevations which ensures uniform distribution even under turndown conditions wherein the holes on the liquid tube are located above the distributor tray deck level, which offers high level of resistance to fouling.
In yet another embodiment of the present invention the secondary distribution attachment provides further distribution of liquid with or without the aid of vapour or gas velocity wherein at high vapour or gas velocity, the vapour or gas assists secondary distribution of liquid and the attachment helps in achieving uniformity of the distribution, which otherwise is quite non-uniform and at low vapour or gas velocity, when the vapour or gas hardly provides any assistance to liquid distribution, the attachment provides excellent secondary distribution of liquid.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS Figure-1: Configuration of trickle bed reactor where the location of the distributor tray (1)
is shown relative to catalyst bed and other reactor internals. Figure-2: Assembly of the distributor tray inside a reactor and orientation of primary
distribution points.
Figure-3: Details of a distributor unit (7). Figure-4: Details of the vapour/gas tube (9). Figure-5: Details of the liquid tube (10). Figure-6: Details of secondary distribution attachment (11). DESCRIPTION OF THE INVENTION
Gas/ liquid two-phase distributor tray is an integral part of trickle bed reactor. In a trickle bed reactor gas and liquid flow downward co-currently through catalyst beds. Performance of catalyst in facilitating desired reactions depends largely on the efficiency of the distributor tray. Following aspects are important for designing the two-phase distributor tray:
Primary distribution of liquid and gas Secondary distribution of liquid
- Turndown of gas and liquid rates

Resistance to fouling
Catalyst used in trickle bed reactors are typically of lmm-3mm size. Such small sized particles have limited capability for radial distribution of liquid. Therefore, for such particles, higher density of distribution points improves performance of the catalyst bed due to better wetting of catalyst particles. Therefore, in addition to primary distribution of liquid through large number of distribution points, the distributor tray is also designed to provide secondary distribution of liquid. As far as distribution of gas phase is concerned, initial distribution through large number of distribution is important. Further distribution of gas is achieved due to high-pressure drop across catalyst bed. To economize the design and engineering as well to fulfill the process requirement high turndown distributors are important. Resistance to fouling offers wider range of applicability reduces maintenance requirements.
The present invention proposes a novel design for distributor tray for use in trickle bed reactors. The novel design of the distributor tray offers high density of primary distribution points, good quality secondary distribution of liquid, high turndown of gas and liquid rates and effective resistance to fouling.
The following embodiments are provided to illustrate the invention is accordance with the principle of the invention, but are not construed as limiting the invention in any way except as indicated in the appended claims.
Figure-1 shows the overall assembly of the distributor tray (1). The distributor (1) is installed in a reactor (2), above a bed (3) of catalyst particles. During normal operation, gas and liquid enter the reactor through the inlet (4) and flows co currently downward through the distributor (1) and the catalyst bed (3) to the outlet (5). Inside the reactor (2), the distributor (1) is supported on a support ring (6) and the support ring is welded to the inside wall of the reactor (2).
The overall assembly of the distribution tray (1) inside a reactor and orientation of primary distribution points is shown in Figure-2. The distributor tray consists of a number of distributor units (7) located on the tray (1). Each distributor unit corresponds to a primary distribution point (8). The number and orientation of primary distribution points (8) depend on design conditions of the distributor tray (1).
The details of a distributor unit are shown in Figure-3. The distributor unit (7) consists of a gas tube (9), a liquid tube (10) and a secondary distribution attachment (11). The gas tube (9) passes through the primary distribution point (8) and welded to the lower surface of the distributor tray (1). The secondary distribution attachment (11) is welded to

the bottom part of the gas tube (9). The liquid tube (10) is concentric and placed outside the gas tube (9). The liquid tube is welded on the upper surface of the distributor tray.
The details of the vapour/gas tube (9) are shown in Figure-4. It consists of a pipe (12), closed from top and open from bottom. Specified number of rectangular slots (13) are there at the top part of pipe for entry of vapour or gas. Specified number of rectangular slots (14) are also present at the bottom edge of the pipe (12) for vapor or gas exit. Specified numbers of circular holes (15) are there just above the distributor tray (1) location for entry of liquid from liquid tube (10) to gas tube (9). A circular cover plate (16) is welded to the pipe (12) just below the top slots (13), which acts as cover for the liquid tube (10).
The details of liquid tube (10) are shown in Figure-5. It consists of a pipe (17) placed concentrically around the gas tube (9) and the annular gap between them is maintained by specified numbers of stoppers (18). The pipe (17) has specified numbers of circular holes (19) at two levels above the location of the distributor tray (1). Liquid from the distributor tray (1) enters into the pipe (17) through these holes (19). The secondary distribution attachment (11) provides further distribution of liquid.
The details of secondary distribution attachment (11) are shown in Figure-6. It consists of a slotted plate (20). Two concentric rings (21 & 22) with serrated bottom are welded to the bottom surface of the slotted plate (20). Specified numbers of vertical baffles (23) are welded to the top surface of the slotted plate (20). The slotted plate (20) has a circular hole (24) at the center. The vertical baffles (23) are so oriented that on welding the secondary distribution attachment (11) to the bottom end of the gas tube (9), the baffles (23) are located at the center of the bottom slots (14). The main advantages of the present invention are:
1. The distributor tray of the present invention has large number of distribution
points which improves performance of the catalyst bed due to better wetting of
catalyst particles.
2. In the present invention the liquid is first distributed through the primary
distribution points and then further distribution of liquid is achieved through
the secondary distribution attachments. The secondary distribution attachments
provide further distribution of liquid with or without the aid of vapour or gas
velocity.

3. At high vapour or gas velocity, the vapour or gas assists secondary distribution
of liquid and the secondary distribution attachment helps in achieving
uniformity of the distribution, which otherwise quite non-uniform.
4. At low vapour or gas velocity, when the vapour or gas hardly provides any
assistance to liquid distribution, the attachment provides excellent secondary
distribution of liquid.
5. The distributor tray of the present invention is resistant to fouling and reduces
maintenance requirements.
6. The novel distributor tray of the present invention ensures uniform distribution
of vapor or gas and liquid even under turndown conditions.
7. In the present invention at very high liquid load, the liquid overflows into the
annular space between the gas tube and the liquid tube without disturbing the
gas flow pattern.

We claim:
1. An apparatus for distributing down flowing vapour or gas and liquid on a catalyst
bed (3) in a trickle bed reactor comprising:
(a) a distributor tray (1) consisting of distributor units (7) wherein each distributor
unit (7) corresponds to a primary distribution point (8); and
(b) each distributor unit (7) consists of a gas tube (9) a liquid tube (10) and a
secondary distribution attachment (11).

2. The apparatus as claimed in claim 1 wherein said distributor tray (1) is connected
to feed pipe (4) through an inlet device for vapour or gas and liquid entry.
3. The apparatus as claimed in any preceding claim wherein said gas tube (9) is
connected to the lower surface of the distributor tray (1) and passes through said
primary distribution point (8).
4. The apparatus as claimed in any preceding claim wherein said secondary
distribution attachment (11) is connected to the bottom part of the gas tube (9).
5. The apparatus as claimed in any preceding claim wherein said liquid tube (10) is
concentric and is connected on the upper surface of the distributor tray (1) and
placed outside the gas tube (9).
6. The apparatus as claimed in any preceding claim wherein said gas tube (9) consists of a
pipe (12), closed from top and open from bottom wherein said pipe (12) comprises:

(a) rectangular slots (13) at the top part of said pipe (12) for vapour or gas entry;
(b) rectangular slots (14) at the bottom edge of the pipe (12) for vapor or gas exit;
(c) circular holes (15) above the distributor tray (1) for liquid entry from liquid
tube (10) to gas tube (9); and
(d) a circular cover plate (16) connected to said pipe (12) below said
rectangular slots (13) which acts as cover for the liquid tube (10).

7. The apparatus as claimed in any preceding claim wherein said liquid tube (10)
comprises a pipe (17), placed concentrically around the gas tube (9) and the
annular gap between said liquid tube (10) and said gas tube (9) is maintained by
stoppers (18) and said pipe (17) further consists of circular holes (19) at two
levels above the distributor tray (1) for liquid entry from said distributor tray (1)
into said pipe (17) through said circular holes (19).
8. The apparatus as claimed in any preceding claim wherein said secondary
distribution attachment (11) provides further distribution of liquid and consists of:

(a) a slotted plate (20) with a circular hole (24) at the center;
(b) two concentric rings (21 and 22) with serrated bottom connected to the
bottom surface of said slotted plate (20); and
(c) vertical baffles (23) connected to the top surface of said slotted plate (20).

9. The apparatus as claimed in claim 8 wherein said vertical baffles (23) are located
at the center of the rectangular slots (14).
10. An apparatus for distributing down flowing vapour or gas and liquid on a catalyst
bed in a trickle bed reactor substantially as hereinbefore described and with
reference to the accompanying drawings.

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=dlJoELQ2QpMtIlLdC7pppA==&loc=+mN2fYxnTC4l0fUd8W4CAA==

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Patent Number

269940

Indian Patent Application Number

6/DEL/2007

PG Journal Number

47/2015

Publication Date

20-Nov-2015

Grant Date

19-Nov-2015

Date of Filing

02-Jan-2007

Name of Patentee

ENGINEERS INDIA LIMITED

Applicant Address

RESEARCH AND DEVELOPMENT DIVISION, RESEARCH AND DEVELOPMENT COMPLEX, SECTOR 16, GURGAON-122001, (HARYANA), INDIA

Inventors:

#	Inventor's Name	Inventor's Address
1	MAJUMDER, KAUSHIK	RESEARCH AND DEVELOPMENT DIVISION, RESEARCH AND DEVELOPMENT COMPLEX, SECTOR 16, GURGAON-122001, (HARYANA), INDIA
2	DATTA, SAMEER KUMAR	RESEARCH AND DEVELOPMENT DIVISION, RESEARCH AND DEVELOPMENT COMPLEX, SECTOR 16, GURGAON-122001, (HARYANA), INDIA
3	BANIK, SUKUMAR	RESEARCH AND DEVELOPMENT DIVISION, RESEARCH AND DEVELOPMENT COMPLEX, SECTOR 16, GURGAON-122001, (HARYANA), INDIA

PCT International Classification Number

B01D3/22; B01D3/14

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA