DESC:FIELD
The present disclosure relates to vertical column structure in the process industry. More particularly, it relates to the chemical and petrochemical industries, where a column assembly is used for distillation, absorption, and stripping.
DEFINITIONS
As used in the present disclosure, the following terms are generally intended to have the meaning as set forth below, except to the extent that the context in which they are used, indicates otherwise.
Column: The term “column” refers to vertical cylindrical column assembly comprising a plurality of sections along with column internals and used for processes such as distillation, absorption, stripping, and extraction.
Intermediate section: The term “intermediate section” refers to the section of a column that needs to be rectified, repaired or replaced by isolating it from the column.
Operative top segment: The term “operative top segment” refers to the assembled sections of the column above the intermediate section.
Operative bottom segment: the term “operative bottom segment” refers to the assembled sections of the column below the intermediate section.
Maintenance: the term “maintenance” refers to the rectification, repair, and/or replacement of the intermediate section in case of failure of any column internals or damage to the glass lining in glass glass-lined section or any other situation where the column section is to be removed or replaced.
Lifting means: the term “lifting means” refers to the component used for the purpose of lifting the operative top segment and/or the intermediate section or any part of the column.
Roller means: the term “roller means” refers to the component used for rolling out or rolling in the intermediate section from the column.
Support structure: The term “support structure” refers to a supporting arrangement for the column. The support structure comprises structural beams and pillars of a building structure usually of steel.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
A vertical column assembly or a process column used in the process industry like chemical and petrochemical processes includes a plurality of sections. The process column is used in various processes such as distillation, absorption, stripping, extraction and the like. The height of this column may be as much as 30 meters or even more and with a variety of column internals viz random/ structured packing, trays of various configurations along with their support systems.
The material of construction (MOC) of the column, sections and its internals are expensive and of special material which can be fragile and brittle. During the operating life of the column, there are situations where a particular intermediate section needs to be removed, exposed or replaced for maintenance, for example, when glass lining fails in glass-lined columns designed for handling highly corrosive fluids. However, replacing the failed or affected section poses significant drawbacks. Further, the section needs to be exposed during the failure of any of the column internals of a particular section, or while accessing the section for the replacement or replenishment of packing, particularly when there are no manholes available, or inadequate to carry out the required work inside the column section or any other similar situation.
Typically, during maintenance or replacement of any particular column, all sections and parts of the column above the intermediate section need to be removed one by one or together using a large crane. After rectification, the sections are assembled one by one from bottom to top throughout the full height of the column. However, there are several disadvantages of this process such as the deployment of an appropriate crane is expensive and its immediate availability may be a challenge in some situations. Further, the process of lifting the section using a crane requires special skills, and it is very effort-intensive. Further, the typical maintenance process is time-consuming causing loss of production and requires very high downtime of the process. Furthermore, the column sections are more susceptible to mechanical impact during handling by crane and can cause damage to the sections or their internals, especially for glass-lined sections and the sections with brittle or fragile column internals.
Therefore, there is felt a need to provide a method of maintenance of an intermediate section of a column that mitigates the above-mentioned drawbacks or at least provides a useful alternative.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows:
It is an object of the present disclosure to ameliorate one or more problems of the background or to at least provide a useful alternative.
An object of the present disclosure is to provide a method of maintenance of an intermediate section of a column.
Another object of the present disclosure is to provide a method of maintenance of an intermediate section of a column that does not require the deployment of an external crane.
Yet another object of the present disclosure is to provide a method of maintenance of an intermediate section of a column that does not require removing all the column sections for the maintenance of the intermediate section.
Still another object of the present disclosure is to provide a method of maintenance of an intermediate section of a column that reduces the probability of damage to the sections and internals due to mechanical handling and impact.
Yet another object of the present disclosure is to provide a method of maintenance of an intermediate section of a column that does not require highly skilled labour and also provides ease of handling the sections.
Still another object of the present disclosure is to provide a method of maintenance of an intermediate section of a column that requires reduced time and effort for the maintenance of the intermediate section.
Yet another object of the present disclosure is to provide a method of maintenance of an intermediate section of a column that is cost-effective and minimizes the loss of production.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
The present disclosure provides a method of maintenance of an intermediate section of a process column comprising a plurality of sections attached to each other and assembled one by one from the bottom to the top. Each of the sections and the entire assembled column is supported on a support structure comprising structural beams and pillars, the sections above the intermediate section comprising an operative top segment of the column and the sections below the intermediate section comprising an operative lower segment of the column, the method comprising the following steps: the intermediate section is isolated from the operative top segment of the column; the operative top segment is raised with the help of a first lifting means to form a first gap between the operative top segment and the intermediate section; the intermediate section is isolated from the operative bottom segment of the column; the intermediate section is raised with the help of a second lifting means to form a second gap between the intermediate section and the operative bottom segment; and the intermediate section is extracted with the help of a roller means and guiding the intermediate section away from the column for the purposes of maintenance.
The method further includes the steps in which the intermediate section is aligned axially with the operative top segment and the operative bottom segment of the column after maintenance; then, the intermediate section is lowered on the operative bottom segment of the column to abut the operative bottom segment; and subsequently securing the intermediate section to the operative bottom segment; further, the operative top segment is lowered on the intermediate section to abut the operative top segment to the intermediate section; and securing the operative top segment to the intermediate section.
In an embodiment, the first lifting means and the second lifting means are selected from a hydraulic jack and a screw jack.
In an embodiment, the first lifting means and the second lifting means are uniformly placed and actuated simultaneously using a hydraulic pump to share the load of the lifted operative top segment and the lifted intermediate section equally.
In an embodiment, a pair of support lugs are configured on either side of the sections to support and carry the load of the section along with column internals and transfer the load onto the beams on either side
In an embodiment, the support lugs are an integral part of a ring beam of the column.
In an embodiment, the first lifting means and the second lifting means are configured to support the support lugs at two pairs of supporting points, wherein the two pairs of supporting points are symmetrically placed opposite to each other.
In an embodiment, the sections are configured to support a plurality of column internals independently irrespective of the other sections of the column.
In an embodiment, the structural beam of the support structure is provided with a guiding track for directing the intermediate section along the length of the beam using the roller means.
In an embodiment, the roller means is at least one selected from castor wheels and a roller.
In an embodiment, a plurality of support blocks are configured in between the support lugs and the structural beam to accommodate thermal expansion or contraction of the sections.
In an embodiment, the support blocks are selected from a spring and a hydraulic mechanism.
In an embodiment, a plurality of temporary blocks are used to temporarily secure the lifted operative top segment and the lifted intermediate section in the raised position, the temporary blocks are made from at least one material selected from the group consisting of steel, wood, RCC block and a combination thereof.
In an embodiment, the first gap is in the range of 100 mm to 200 mm, and the second gap is in the range of 80 mm to 120 mm.
In an embodiment, the maintenance of the intermediate section includes rectification, repairing, and/or replacement of the intermediate section along with the column internals.
In an embodiment, the method is being deployed without the help of cranes.
In an embodiment, the intermediate section is the bottommost section and the operative bottom segment is absent.
In an embodiment, the intermediate section is the topmost section and the operative top segment is absent.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWING:
The present disclosure will now be described with the help of the accompanying drawing, in which:
Figure 1 illustrates a typical arrangement of a process column structure comprising a column and a support structure according to an embodiment of the present disclosure;
Figure 1a illustrates a top view of the column and the support structure of Figure 1;
Figure 2 illustrates a method for the maintenance of the sections using lifting means in accordance with an embodiment of the present disclosure;
Figure 2a illustrates lifting means placed on both sides of the section and in between support lugs and beams of the topmost section in accordance with an embodiment of the present disclosure;
Figure 3 illustrates a method step for rolling out the intermediate section for maintenance in accordance with an embodiment of the present disclosure; and
Figure 3a illustrates a top view of the intermediate section at a rolled-out position during maintenance in accordance with an embodiment of the present disclosure.
LIST OF REFERENCE NUMERALS
Reference numerals Description
1000 Process column structure
100 Column
102 Top dome
104 Sections
104’ Intermediate section for maintenance
106 Support lugs
106a Ring beam
108 Support blocks
110 Beams
112 Bottom sump
114 Pillars
116 Stage
200 Support structure
202 lifting means
202a First lifting means
202b Second lifting means
204 First gap
300 Temporary blocks
304 Second gap
306 Roller means
308 First predetermined position
310 Second predetermined position
C1 First/topmost section
Cn nth section

DETAILED DESCRIPTION
The present disclosure relates to a method of maintenance of an intermediate section of a process column (100).
Embodiments, of the present disclosure, will now be described with reference to the accompanying drawing.
Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, known processes or well-known apparatus or structures, and well-known techniques are not described in detail.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms "a,” "an," and "the" may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms "comprises," "comprising," “including,” and “having,” are open ended transitional phrases and therefore specify the presence of stated features, integers, steps, operations, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The particular order of steps disclosed in the method and process of the present disclosure are not to be construed as necessarily requiring their performance as described or illustrated. It is also to be understood that additional or alternative steps may be employed.
The terms first, second, third, etc., should not be construed to limit the scope of the present disclosure as the aforementioned terms may be only used to distinguish one element, component, region, layer or section from another component, region, layer or section. Terms such as first, second, third etc., when used herein do not imply a specific sequence or order unless clearly suggested by the present disclosure.
As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed elements.
A vertical process column structure is commonly used in the chemical and petrochemical industries and consists of multiple column sections. This process column plays a crucial role in processes such as distillation, absorption, stripping, and extraction. The height of the column can reach up to 30 meters or more and incorporates various types of internals, including random and structured packing, as well as different tray configurations along with their support systems.
The materials used for the column and its internals are often costly and made of special materials that can be fragile and brittle. Throughout its operational life, situations may arise that require the removal or exposure of a particular intermediate section to access internals for maintenance. For instance, in glass-lined columns that handle highly corrosive fluids, a failure in the glass lining necessitates replacing the affected section, which can present significant challenges. Additionally, accessing a column section to replace or replenish packing can be difficult, especially in the absence of adequate manholes or when the available access points are insufficient for the required work.
Typically, during maintenance or replacement of the intermediate section, all sections and the parts above the intermediate section must be removed, either one by one or collectively using a large crane. After repairs, these sections are reassembled from the bottom up, spanning the full height of the column. However, this process has several significant drawbacks.
First, securing a suitable crane is costly and may not always be readily available, leading to potential delays. Additionally, the operation of lifting sections with a crane, demands specialized skills and is highly labor-intensive. This maintenance procedure is also notably time-consuming, resulting in production losses and extended downtime for the process.
Moreover, handling the column and sections with a crane or with other conventional maintenance procedures increases the risk of mechanical impacts, which can cause damage to both the sections and their internals. This is particularly concerning for glass-lined sections and those containing brittle or fragile internals, making the entire process even more problematic
Therefore, the present disclosure provides a simplified method related to the maintenance of the intermediate section of a column (100).
The method of maintenance of the intermediate section of the column (100) advantageously does not require the deployment of an external crane. The method of the present disclosure will now be described in detail with reference to Figures 1 through Figure 3c. The present embodiment does not limit the scope and ambit of the present disclosure.
A method of maintenance of an intermediate section of a process column (100) comprising a plurality of sections (104) attached to each other and assembled one by one from the bottom to the top. Each of the sections (104) and the entire assembled column (100) are supported on a support structure (200). The support structure comprises structural beams (110) and pillars (114). The sections above the intermediate section comprise an operative top segment of the column (100) and the sections below the intermediate section comprise an operative lower segment of the column (100). The method comprises the following steps:
i. isolating the intermediate section from the operative top segment of the column (100);
ii. raising the operative top segment with the help of a first lifting means (202a) to form a first gap (204) between the operative top segment and the intermediate section;
iii. isolating the intermediate section from the operative bottom segment of the column (100);
iv. raising the intermediate section with the help of a second lifting means (202b) to form a second gap (304) between the intermediate section and the operative bottom segment; and
v. extracting the intermediate section with the help of a roller means (306) and guiding the intermediate section away from the column (100) for the purposes of maintenance.
The method of the present disclosure provides a hassle-free isolation, extraction and maintenance of the intermediate section of the column (100) without the help of cranes.
In an exemplary embodiment, the intermediate section that is to be repaired is the bottommost section (C6) of the column (100) and is denoted by “(104’)”. The intermediate section (104’) and the column (100) are depicted in Figure 2 and Figure 3 of the present disclosure. The operative top segment is the segment above the intermediate section (104’) including the sections (C1-C5) and the operative bottom segment is absent. The intermediate section (104’) is directly connected to the bottom sump (112).
In the first step, the intermediate section (104’) is isolated from the operative top segment (C1-C5) of the column (100). For the isolation of the intermediate section (104’) from the operative top segment (C1-C5) of the column (100), all the connections of the intermediate section (104’) are removed from the section (C5) directly above it.
In an exemplary embodiment, the intermediate section (104’) is to be isolated from the operative top segment (C1-C5) and the top dome (Td) for maintenance purposes. For isolation, all the safety precautions should be followed such as cleaning up the entire column (100) of all process fluid and ensuring that there is no toxic, flammable, corrosive, or any other substance present in the column (100). Wash and rinse the column (100) and its internals, and purge to remove any hazardous vapours or gases. Then, all the flange connections are removed and other utility connections such as the process pipeline, electrical, steam, water or air connection should be detached so that the column (100) is free from all obstruction and safe to lift. Also, ensure to obtain a work permit from the safety authority for the replacement of the damaged intermediate section (104’).
Further, the top flange connection of the intermediate section (104’) and the bottom flange connection of the section (C5) of the operative top segment is disconnected. This ensures a disconnection of the operative top segment (C1-C5) and top dome (102) from the intermediate section (104’).
In the second step, the operative top segment (C1-C5) is raised with the help of a first lifting means (202a) to form a first gap (204) between the operative top segment (C1-C5) and the intermediate section (104’).
After the safe isolation of the operative top segment (C1-C5) from the intermediate section (104’), the operative top segment (C1-C5) along with the top dome (102) is raised in the assembled condition to form a first gap (204) between the operative top segment (C1-C5) and the intermediate section (104’). The first gap (204) is formed with the help of the first lifting means (202a).
To facilitate the lifting of the operative top segment (C1-C5), each of the sections of the column (100) is configured with a support lug (106) on a peripheral portion of each of the sections (104) to support and carry a load of the sections (104).
In an embodiment, the support lugs (106) are configured in a pair on either side of the sections (104) to support and carry a load of the section (104) along with column internals and transfer the load onto the beams (110) on either side.
In an exemplary embodiment, the first lifting means (202a) is placed between support lugs (106) and the beams (110) of a topmost column section (C1) of the column (100) to lift the operative top segment (C1-C5) along with the top dome (102) at a first predetermined height to form a first gap. Once the first gap is created, secure the operative top segment (C1-C5) at the lifted position using temporary blocks (300).
In an embodiment, the first predetermined height (204) or the first gap (204) is in the range of 100 mm to 200 mm.
In an embodiment, the temporary blocks (300) are made from at least one material selected from the group consisting of steel, wood, RCC block, or any other block capable of temporarily supporting the loads and a combination thereof.
In the third step, the intermediate section (104’) is isolated from the operative bottom segment of the column (100).
To facilitate isolation, all the flange connections of the intermediate section (104’) to the operative bottom segment are removed. Further, the connections such as the processing pipeline, electrical, steam, water or air connection are detached, and a work-to permit is obtained from the safety authority.
In an exemplary embodiment, the intermediate section (104’) is directly connected to the bottom sump (Bs) hence the connections between the bottom flange of the intermediated section (104’) and the flange of the bottom sump (Bs) are removed.
In an embodiment, the intermediate section is the bottommost section and the operative bottom segment is absent. The intermediate section is directly connected to the bottom sump (Bs)
In the fourth step, the intermediate section (104’) is raised with the help of a second lifting means (202b) to form a second gap (304) between the intermediate section (104’) and the operative bottom segment.
For raising the intermediate section (104’), the second lifting means (202b) are placed between support lugs (106) and a beam (110) of the intermediate section (104’) of the column (100). The second lifting means (202b) raises the intermediate section at a second predetermined height to form a second gap (304) between the intermediate section (104’) and the operative bottom segment (Bs) and secure the intermediate section (104’) at the lifted position using temporary blocks (300).
In an embodiment, the second predetermined height (304) or the second gap (304) is in the range of 80 mm to 120 mm.
The first gap (204) and the second gap (304) are created to ensure there is adequate space for rolling in and rolling out of the intermediate section (104’) for maintenance. These first and second gaps may vary from case to case depending on the size and type of the column and accordingly, the specific type of the first lifting means (202a) and the second lifting means (202b) are selected.
In an embodiment, the first lifting means (202a) and the second lifting means (202b) are selected from a hydraulic jack and a screw jack.
In an exemplary embodiment, four numbers of hydraulics jacks are used, 2 on each side of the section in between the support lugs (106) and the beam (110) of the corresponding section (104).
In an exemplary embodiment, the loading capacity of each of the lifting means (202) is in the range of 15 MT to 40 MT.
The first lifting means (202a) and the second lifting means (202b) are uniformly placed below the support lugs (106) of the section (104) and are actuated simultaneously using a hydraulic pump to share the load of the lifted sections (104) or lifted segments equally. The lifted section or the lifted segment should be always below the plane of the lifting means (202).
In an embodiment, the first lifting means (202a) and the second lifting means (202b) are configured to support the support lugs (106) of the sections (104) at two pairs of supporting points, wherein the two pairs of supporting points are symmetrically placed opposite to each other.
In an embodiment, the support lugs (106) are an integral part of a ring beam (106a) of the column (100).
In the fifth step, the intermediate section (104’) is extracted with the help of a roller means (306) and guided the intermediate section (104’) away from the column (100) for the purposes of maintenance.
In the process of extraction of the intermediate section (104’), the temporary blocks (300) and the second lifting means (202b) are replaced by a roller means (306) and rolling out the intermediate section (104’) from a first predetermined position (308) to a second predetermined position (310).
In an embodiment, a guiding track is provided on the structural beam (110) that facilitates the guiding of the intermediate section (104’) away from the column (100) to the second predetermined position (310) with the help of roller means (306). The roller means (306) slides over the guiding track for easy extraction of the intermediate section (104’).
In an embodiment, the roller means (306) is at least one selected from castor wheels and a roller.
Once the intermediate section (104’) is extracted, the maintenance processes are carried out. In the maintenance process, the intermediate section (104’) undergoes rectification or repair. In some instances, the intermediates section (104’) is replaced with another section. In the maintenance process, the intermediate section (104’) is repaired, in case of failure of any column internals or damage to the glass lining in the glass-lined section or any other situation where the column section is to be removed or replaced. In some cases, replenishment of column packing requiring access from the top of a particular section especially when there are no manholes or access through the manhole is not feasible or adequate to carry the required work inside the section.
After completion of the maintenance process, the rectified intermediate section (104’) is aligned axially with the column (100) using the following steps:
vi. aligning the intermediate section axially with the operative top segment and the operative bottom segment of the column (100) after maintenance;
vii. lowering the intermediate section on the operative bottom segment of the column (100) to abut the operative bottom segment;
viii. securing the intermediate section to the operative bottom segment;
ix. lowering the operative top segment on the intermediate section to abut the operative top segment to the intermediate section; and
x. securing the operative top segment to the intermediate section.
The method of extraction and maintenance is further followed by the method steps of aligning the rectified intermediate section. In this method step, the rectified intermediated section (104’) is aligned and secured with the column (100) for further operation.
In the sixth step, the intermediate section (104’) is aligned axially with the operative top segment (C1-C5) and the operative bottom segment of the column (100) after maintenance.
For aligning the intermediate section, the intermediate section is rolled into the first predetermined position (308) from the second predetermined position (310) using a roller means (306) and aligning axially with the operative top segment (C1-C5) and the operative bottom segment of the column (100). Then, the second lifting means (202b) are placed, replacing the roller means (306) with the temporary block (300).
In the seventh and eighth steps, the intermediate section (104’) is lowered on the operative bottom segment of the column (100) to abut the operative bottom segment and securing the intermediate section to the operative bottom segment by establishing the all connections.
The second lifting means (202b) are gradually retracted to lower the intermediate section (104’) to minimize the second gap (304) created between the lower flange of the intermediate section (C6) and the top flange of the operative bottom segment of the column (100). In this case, the operative bottom segment is absent hence the intermediate section is directly connected to the bottom sump (Bs). Once the intermediate section (104’) is lowered, check the vertical alignment of the intermediate section (104’) with the column (100) and restore all connections with the bottom sump (Bs).
In the ninth and tenth steps, the operative top segment (C1-C5) along with the top dome (102) is lowered onto the intermediate section (104’) to abut the section (C5) of the operative top segment (C1-C5) to the intermediate section (104’); and securing the operative top segment (C1-C5) to the intermediate section (104’). For lowering the operative top segment (C1-C5), the temporary blocks (300) placed below the topmost column section are removed and the first lifting means (202a) are slowly retracted to lower the operative top segment (C1-C5) onto the intermediate section (104’).
Once the operative top segment (C1-C5) is completely lowered, check the alignment of the operative top segment (C1-C5) with the intermediate section (104’) and establish the connection between the bottom flange of the section (C5) of the operative top segment (C1-C5) and the top flange of the intermediate section (104’).
In an exemplary embodiment, for the maintenance of the bottom sump Bs (112), the operative top segment includes the sections (C1-C6) and the operative top segment (C1-C6) along with the top dome (102) has to be lifted using the lifting means (202) for the maintenance of the bottom sump Bs (112). The top dome is easily accessible from the top, for the maintenance of the top dome (102) the flange connection between the topmost column section (C1) and the top dome (102) is removed.
In an embodiment, the sections (104) are configured to support a plurality of column internals independently irrespective of the other sections of the column (100). The independent support of the column internal in the section (104) facilitates the easy extraction and maintenance of the intermediate section (104’). The column internals can be a support grid of random or structured packings, trays, a liquid distributor, and a redistributor.
The column sections (104) are carefully engineered to ensure that they can support their own internals, which may include various components such as support grids for packing, packing materials themselves, distributors, redistributors, and any additional internals.
Each column section functions independently, which means the column section’s internals are not reliant on the neighbouring column sections for support. This configuration advantageously allows independent lifting and isolation of the particular column section for maintenance, because each column section and its internals are self-supporting, they can be lifted and handled separately during maintenance or repairs. This minimizes the need for extensive disassembly of the entire column, making the process more efficient.
Further, the independent column section provides ease of maintenance in the case where a particular internal component, such as a distributor or packing, requires replacement or servicing, only the relevant column section needs to be accessed. This isolation simplifies the maintenance process and reduces downtime. In addition, the independent column section ensures that the load-bearing capacity of each column section is adequate to support the specific internals it contains. This structural integrity is crucial, especially for fragile materials, such as glass linings or delicate packing, preventing damage during operation and maintenance.
The support structure (200) is a framework, that provides the supporting arrangement to the column (100). The support structure (200) is built in such a way that the combined contribution of the beam and the pillar of the support structure provides an ease of handling of the column section for maintenance. For each column section, a separate window or stage (116) is formed by the pair of beams (110) and pillars (114), allowing for easy isolation and rectification of the desired column section (104’).
The support structure is capable of supporting the load of the entire column assembly (100) along with column internals since the load of the entire column assembly will be transferred to the structural beams (110).
In an embodiment, a plurality of support blocks (108) is configured in between the support lugs of the section and the structural beam (110) to accommodate thermal expansion or contraction of the sections (104).
In an embodiment, the support blocks (108) are selected from springs and a hydraulic mechanism.
In an embodiment, the intermediate section (104’) is the topmost section and the operative top segment is absent.
The foregoing description of the embodiments has been provided for purposes of illustration and is not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment, but, are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
The present disclosure is further illustrated herein below with the help of the working example. The working example used herein is intended merely to facilitate an understanding of the ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the example should not be construed as limiting the scope of embodiments herein.
EXAMPLES
The working example data is tabulated herein below in Table 1:
Table 1:
Sr. no Description Dimension
A Diameter of the sections (C1 to C6) top dome (Td) and bottom sump (Bs) 1.30 meters (m)
B Height of the sections (C1 to C6) 4.00 meters
C Height of top dome (Td) and bottom sump (Bs) 1.25 meters
D Maximum Weights including packing, accessories, insulations and the like during maintenance activity
i. Sections (C1 -C6)
ii. Bs and Td

10 metric tons (MT)
5.0 MT
E First lifting means (202a)
i. Capacity (each Hydraulic Jack)
ii. Maximum Outside Diameter
iii. Maximum retracted height
iv. Minimum extended height
30 MT
125 mm
250 mm
400 mm
F Support blocks (108) (Set of 4 nos of Fabricated Steel stools bolted to bolted to beams 110 supporting Column sections)
i. Minimum Capacity of each support block
ii. Height of each support block (+/- 2mm)

30 MT

260 mm
G Temporary block (300)
i. Diameter
ii. Minimum Capacity of each Temporary block
iii. Height of each support block (+/- 2mm)
125 mm
30 MT

395 mm
H Second lifting means (202b)
i. Capacity (each Hydraulic Jack)
ii. Maximum Outside Diameter
iii. Maximum retracted height
iv. Minimum extended height
20 MT
125 mm
250 mm
350 (+/- 10 mm) mm
I Roller means (306) (Castor wheels) with bolt holes matching Support lugs (106)
i. Capacity of each rolling means
ii. Maximum Height of each rolling means
iii. Minimum Height of each rolling means

5 MT
325 mm

300 mm
J Centre to Centre distance between first position (308) & Second position (310)
2.0 meter to 2.5 meter
K Working Hours per Day 10Hrs/day

EXAMPLE 1
The extraction of the intermediate section from the column (100) and maintenance in accordance with the present disclosure saves time and is cost-effective. The method in accordance with the present disclosure does not use a crane, resulting in significantly less time needed to extract and realign the intermediate section compared to conventional systems and methods. The steps of the method in accordance with the present disclosure are detailed below in Table 2.
Table 2:
Step No Description Estimated time in each step
(Hrs : Min)
1 Cleaning up the entire column off all process fluids and ensuring that there is no toxic, flammable, explosive, corrosive or any other hazardous substances present. Wash or rinse the column and column internals, purge to remove any hazardous vapours or gases. Then Isolate the Top Dome Td from all connecting parts above it and Column section C6 from Bottom Sump Bs below it along with all connections (viz. process pipelines, utilities viz Electrical, steam, water, air and the like) to ensure that Column comprising of section (C1 to C6 and Top dome (Td)) are free from all obstructions and safe to lift the operative top segment (C1- C5) and Td in assembled condition from the intermediate section(104’). Obtain Permit to Work for replacement of damaged intermediate section (104’) i.e., section “C6” 4:00
2 Isolating by opening the Flange bolts between the top flange of the intermediate section (C6) and the Bottom flange of the operative top segment and disconnecting the operative top segment (C1 to C5) along with the Top dome (Td) from the intermediate section (C6) 4:00
3 Placing the first lifting means (202a) i.e., 4 nos of Hydraulic Jacks – 2 hydraulic jacks each between the support lug (106) and beams (110) of the topmost section (C1).
Connecting the hydraulic jacks with hoses to a common manifold and a common hydraulic pump. Parallel activity with Steps 1 & 2 and requiring less than time for steps 1 & 2
4 Lifting the operative top segment (C1-C5 & Td) to an extended height of the first lifting means (i.e., 4 Nos of hydraulic jacks) of 400 mm. 2:00
5 Placing temporary blocks (300) comprising of 4 steel blocks – 2 on each side of the topmost section (C1) between the support lugs (106) and beams of section C1. Then fill up the gap between the bottom of support lugs (106) and temporary blocks (300) by placing steel plate packings of size 100 mm x 100 mm x 5 mm thick in the gap between the temporary blocks (300) and the support lugs (106) in the extended position of the first lifting means (202a) to secure the column in the raised position. 1:00
6 Unbolt and remove 4 Nos of support blocks (108) on Beams (B6) on each side of the intermediate section (C6). 1:00
7 Isolating the intermediate section (C6) from the operative bottom segment (in the present example the operative bottom segment is absent hence next section below the intermediate section is Bottom sump Bs) by opening and removing the flange bolts & gasket. Remove any instrument, any connecting pipes, hoses and the like connected to the intermediate section (C6). 2:00
8 Placing the second lifting means (202b) i.e., 4 nos of the Hydraulic jack - 2 each between the support lugs (106 ) and the beams of the intermediate section (C6).
connecting the hydraulic jacks with hoses to a common manifold and the common hydraulic pump. Start pumping and extending the second lifting means (i.e., 4 nos Hydraulic jacks) to an extended height of 350 (+/- 10) mm 1:00
Fix Roller means (306) comprising of 4 nos Castor Wheels to Support lugs (106) of the intermediate section (C6). 1:00
9 Removing the platform (grating or chequered plates) between beams (B6) on both sides of the column to free up the space for moving the intermediate section (C6) over the beams. 1:00
10 For extracting the isolated intermediate section (C6), Slowly lower the intermediate section (C6) till the Roller means (306) i.e., Castor wheels are placed on beams (B6). The beams (B6) are provided with a guiding track (constraining channel) for castor wheels to move in a predetermined path. Remove the second lifting means (202b) after retracting it to its retracted height. Then roll out the damaged intermediate section C6 in the channel on Beams (B6) from the first predetermined position (308) to the second predetermined position (310) as shown in Figure 3 of the accompanying drawing. 2:00
11 Prepare replacement intermediate section (C6) complete with packing /internals and with another set of Roller means (306) and place it on the floor by other means available in the plant. Parallel preparatory work done earlier
12 Remove the damaged intermediate section (C6) from its position and put in place a replacement intermediate section C6 after preparation (as mentioned in step 10) with castor wheels in the channels on beams B6. 2:00
13 Rolling in this replacement intermediate section (C6) to its designated position in the column (100), check internals, and get process clearance. 2:00
14 Placing the second lifting means (202b) between the support lugs and the beams B6 of the intermediate section (C6) and use it (the hydraulic jacks) as in step 7 by 20-25 mm sufficient to unbolt and remove the roller means (306). 2:00
15 placing the support blocks (108) in their designated position and slowly lowering the intermediate section (C6) using the second lifting means (202b) by retracting the hydraulic jack, carefully while aligning the bottom flange of the intermediate section (C6) with the top flange of the bottom sump (Bs). Place the gaskets and fix the flange bolts between the bottom flange of the intermediate section (C6) with the top flange of the bottom sump (Bs) 2:00
16 Remove the temporary blocks (300) and packing plates which were put in step 4 to secure the operative top segment in its lifted position.
Lowering the operative top segment (C1-C5 and Td) slowly by retracting the first lifting means (202a) while aligning the bottom flange of section (C5) with the top flange of section (C6) using walky-talky or any other suitable communication means. Fix the gaskets and flange bolts. 4:00
ESTIMATED TOTAL TIME 28 HRS
@ 10 HRS MAXIMUM PER DAY DURING DAYLIGHT 3 Days approx.

Example 2.
The conventional method for the maintenance of the column section of the column is described in Table 3. The conventional method is performed by using a large crane. The method steps and time taken for the replacement of the damaged intermediate section (C6) are as follows.
For the conventional method, some assumptions were made;
1. Access is available for the crane to position itself to be able to lower the hook over the top of the column (100) through the roof of the vertical column structure (1000).
2. A Suitable Mobile Crane with a telescopic boom, having a capacity of a minimum of 80 MT at the required extended boom length (approx. 50 m) can be mobilized within 48 hours.
3. The top dome (Td) with its Lifting lug is designed for lifting the entire column with internals and packings ( of capacity 70 MT).
4. The roof of the vertical column structure (1000) is removable.
5. Support lugs of the sections are normal design (typically 4 lugs, transferring load to beams without provision of inserting Hydraulic jacks below the support lugs and such sections are isolated/removed by providing temporary arrangements.
Table 3:
Step No Description Estimated time
(Hrs: Min)
Remarks

1 Identifying suitable Crane hiring agencies, getting them at the site for a survey for assessing feasibility, hiring duration, commercial agreement and the like, 48:00
2 Mobilizing crane to site, making safe lifting plan, and placing it in position plus preparatory time 24:00
3 Preparatory work of cleaning, disconnection Column assembly of C5 and above (same as steps 1 & 2 of the method of the present disclosure) 8:00
4 Remove the roof structure Parallel activity Can be done earlier
5 Lowering the Crane hook over Td, tying with lifting tackles (D-shackles, Slings etc.), and preparing for the lift 4:00
6 Lifting the column section from the top dome (Td) to the intermediate section (C6) by 450 to 500 mm and placing the temporary blocks (300) below the support lugs 106 of the top most section (C1) (same as in Step 5 earlier of the method of the present disclosure) 2:00
7 Disconnecting the intermediate section (C6) from the bottom sump (Bs) as in steps 5, 6 & 7 as disclosed earlier in the method of the present disclosure 4:00
8 Lifting and moving the damaged intermediate section (C6) from its designated position by making special arrangements 8:00 Assumes preparation done earlier
9 Bring in a replacement intermediate section (C6) using special arrangements in its designated position above the bottom sump (Bs). 4:00
10 Lowering the replacement intermediate section (C6) using special arrangements while aligning its bottom flange with the top flange of the bottom sump Bs, placing gaskets and fixing flange bolts 6:00
11 Lowering column section (C to C5) along with top dome (Td) held by crane (and also secured by additional means (e.g., wooden blocks, steel blocks, etc available in the plant) so far while aligning bottom flange of section (C5) with top flange of the intermediate section (C6), place gasket and bolt up 6:00
ESTIMATED TOTAL TIME 66 Hrs
@ 10 HRS MAXIMUM PER DAY DURING DAYLIGHT 7 Days approx.

Inference: example 1, table 2 provided herein above discloses the method of extracting and repairing /replacing the intermediate section in accordance with the present disclosure and example 2, table 3 provided herein above discloses the conventional method using the deployment of the cranes. From Example 1 and Example 2, it is demonstrated that the time taken to detach and realign the intermediate section of the column is considerably reduced in the method outlined in Example 1. The conventional method requires about four more days than the method described in the present disclosure. As a result, the method outlined here in Example 1 is considered to be technically more advanced than the conventional method provided in Example 2.
TECHNICAL ADVANCEMENTS
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of: a method of maintenance of an intermediate section of a column that;
• requires much reduced time and effort while performing a maintenance operation
• does not require the deployment of an external crane;
• does not require to remove all the column sections;
• reduced probability of damage while mechanical handling; and
• is cost-effective and minimizes the loss of production.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
The foregoing description of the specific embodiments so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the invention to achieve one or more of the desired objects or results. While certain embodiments of the inventions have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Variations or modifications to the formulation of this invention, within the scope of the invention, may occur to those skilled in the art upon reviewing the disclosure herein. Such variations or modifications are well within the spirit of this invention.
The numerical values given for various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the invention unless there is a statement in the specification to the contrary.
Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
The numerical values given for various physical parameters, dimensions, and quantities are only approximate values and it is envisaged that the values higher than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the invention unless there is a statement in the specification to the contrary.
While considerable emphasis has been placed herein on the specific features of the preferred embodiment, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiment without departing from the principles of the disclosure. These and other changes in the preferred embodiment of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation. ,CLAIMS:WE CLAIM:
1. A method of maintenance of an intermediate section of a process column (100) comprising a plurality of sections (104) attached to each other and assembled one by one from bottom to the top, each of said sections (104) and the entire assembled column (100) supported on a support structure (200) comprising structural beams (110) and pillar (114), the sections above said intermediate section comprising an operative top segment of said column (100) and the sections below said intermediate section comprising an operative lower segment of said column (100), said method comprising the following steps:
i. isolating said intermediate section from said operative top segment of said column;
ii. raising said operative top segment with the help of a first lifting means (202a) to form a first gap (204) between said operative top segment and said intermediate section;
iii. isolating the intermediate section from said operative bottom segment of said column (100);
iv. raising said intermediate section with the help of a second lifting means (202b) to form a second gap (304) between said intermediate section and said operative bottom segment; and
v. extracting said intermediate section with the help of a roller means (306) and guiding said intermediate section away from said column (100) for the purposes of maintenance.
2. The method as claimed in claim 1, which further includes the steps of:
vi. aligning said intermediate section axially with said operative top segment and said operative bottom segment of said column (100) after maintenance;
vii. lowering said intermediate section on said operative bottom segment of said column (100) to abut said operative bottom segment;
viii. securing said intermediate section to said operative bottom segment;
ix. lowering said operative top segment on said intermediate section to abut said operative top segment to said intermediate section; and
x. securing said operative top segment to said intermediate section.
3. The method as claimed in claim 1, wherein said first lifting means (202a) and said second lifting means (202b) are selected from a hydraulic jack and a screw jack.
4. The method as claimed in claim 1, wherein said first lifting means (202a) and said second lifting means (202b) are uniformly placed and actuated simultaneously using a hydraulic pump to share the load of said lifted operative top segment and said lifted intermediate section equally.
5. The method as claimed in claim 1, wherein a pair of support lugs (106) are configured on either side of said sections (104) to support and carry a load of said section (104) along with column internals and transfer the load onto said beams (110) on either side.
6. The method as claimed in claim 5, wherein said support lugs (106) are an integral part of a ring beam (106a) of said column (100).
7. The method as claimed in claim 1, wherein said first lifting means (202a) and said second lifting means (202b) are configured to support said support lugs at two pairs of supporting points, wherein said two pairs of supporting points are symmetrically placed opposite to each other.
8. The method as claimed in claim 1, wherein said sections (104) are configured to support a plurality of column internals independently irrespective of the other sections of said column (100).
9. The method as claimed in claim 1, wherein said structural beam (110) of said support structure (200) is provided with a guiding track for directing said intermediate section along the length of said beam (110) using said roller means (306).
10. The method as claimed in claim 1, wherein said roller means (306) is at least one selected from castor wheels and a roller.
11. The method as claimed in claim 1, wherein a plurality of support blocks (108) are configured in between said support lugs and said structural beam of said section (104) to accommodate thermal expansion or contraction of said sections (104).
12. The method as claimed in claim 11, wherein said support blocks are selected from springs and a hydraulic mechanism.
13. The method as claimed in claim 1, wherein a plurality of temporary blocks (300) are used to temporarily secure said lifted operative top segment and said lifted intermediate section in the raised position, said temporary blocks (300) are made from at least one material selected from the group consisting of steel, wood, RCC block and a combination thereof.
14. The method as claimed in claim 1, wherein said first gap (204) is in the range of 100 mm to 200 mm and said second gap (304) is in the range of 80 mm to 120 mm.
15. The method as claimed in claim 1, wherein said maintenance of said intermediate section includes rectification, repairing and/or replacement of said intermediate section along with the column internals.
16. The method as claimed in any one of the preceding claims, said method being deployed without the help of cranes.
17. The method as claimed in any one of the preceding claims, wherein said intermediate section is the bottommost section and the operative bottom segment is absent.
18. The method as claimed in any one of the preceding claims, wherein said intermediate section is the topmost section and the operative top segment is absent.

Dated this 30th Day of October, 2024

_______________________________
MOHAN RAJKUMAR DEWAN, IN/PA – 25
OF R. K. DEWAN & CO.
AUTHORIZED AGENT OF APPLICANT

TO,
THE CONTROLLER OF PATENTS
THE PATENT OFFICE, AT MUMBAI