How to Plan Lifting and Rigging for Large Segmented Tower Internals

Large tower internals may be light compared with pressure-vessel components, but they are often awkward to handle.

A liquid distributor, collector, support grid, demister frame, or large structured-packing segment may be:

• thin;
• flexible;
• difficult to grip;
• sensitive to local bending;
• too large for simple manual handling.

This creates a project question that should be answered before shipment:

How will each internal be lifted, transferred through the manway, rotated, and placed at its final elevation without damaging it?

A component that is easy to fabricate may still be difficult to install.

Rigging Starts During Design

Installation planning should not begin when the crate reaches the site.

During design, consider:

• component dimensions;
• weight;
• center of gravity;
• manway size;
• lifting direction;
• final installed orientation.

The segmentation strategy should reflect how individual pieces can actually be handled inside the vessel.

Weight Alone Is Not Enough

A 40 kg thin distributor panel may be harder to handle safely than a compact 100 kg component.

Large flexible panels can:

• sag;
• twist;
• buckle;
• strike the tower wall.

Handling risk therefore depends on:

Weight + Shape + Stiffness + Access

not simply kilograms.

Identify Suitable Lifting Points

Thin-sheet internals should not automatically be lifted from:

• distributor holes;
• mesh;
• thin sheet edges;
• random convenient openings.

The lifting location should transfer load into a sufficiently strong part of the component.

Where dedicated temporary lifting points are required, they should be defined before fabrication.

Check the Center of Gravity

An asymmetric internal may rotate unexpectedly when lifted.

Examples include:

• distributor channels;
• collector panels with gas risers;
• frames with uneven reinforcement.

A lifting plan should understand approximately where the center of gravity lies so the component remains controllable.

Manway Entry Is a Separate Handling Stage

Passing through a manway may require a segment to be:

• vertical;
• tilted;
• rotated;
• temporarily reoriented.

The maximum segment dimension should therefore consider the full movement path rather than only the final installed position.

A segment may technically be smaller than the manway diameter and still be difficult to maneuver because of:

• manway neck length;
• platforms;
• internal beams;
• nearby nozzles.

Protect Thin Edges

Thin stainless-steel edges can be bent during lifting.

Once bent, they may cause:

• poor segment fit;
• excessive gaps;
• interference;
• sharp installation hazards.

Temporary edge protection can be useful during transport and lifting where appropriate.

Do Not Use Functional Openings as Rigging Points Without Approval

Distributor orifices, gas risers, drainage openings, and mesh retainers are designed for process functions.

They are not automatically structural lifting points.

Using them for rigging can distort critical geometry.

Consider the Internal Installation Route

A practical installation review may follow:

Crate→ Laydown Area→ Tower Platform→ Manway→ Internal Temporary Handling Point→ Final Elevation→ Final Assembly

Every transfer stage should be physically possible.

Large Segmented Internals May Need an Assembly Sequence

Suppose a distributor contains six segments.

Installing Segment 1 may block the path required for Segment 6.

Therefore the lifting plan should coordinate with the assembly sequence.

This is especially important where segments:

• overlap;
• interlock;
• bolt from one side only.

Rigging Loads Can Differ From Operating Loads

A collector may be designed to support process loads when installed horizontally.

During lifting, it may temporarily hang vertically.

The resulting load path can be completely different.

A component that is strong in service may still be vulnerable during handling.

Do Not Assume Site Cranes Solve Internal Handling

A crane may bring a crate to the tower platform.

Inside the vessel, handling may depend on:

• chain blocks;
• approved temporary lifting points;
• internal beams;
• site rigging systems.

The supplier needs enough site information to design practical segment sizes.

Mark Lifting Orientation Where Necessary

For unusual components, packaging or drawings can indicate:

• TOP;
• THIS SIDE UP;
• lifting point;
• centerline;
• installation orientation.

This reduces field guesswork.

Trial Handling Can Be Valuable

For particularly difficult components, the fabrication shop may verify that:

• lifting points are accessible;
• the component remains stable;
• slings do not crush thin sections.

This does not replace the site lifting plan but can expose obvious problems.

Protect Finished Surfaces

Rigging chains or unprotected steel contact can damage:

• stainless surfaces;
• polymer coatings;
• thin mesh.

Suitable protection should be considered where surface condition matters.

Lifting Plans Must Follow Site Safety Requirements

Final rigging methods, lifting equipment capacity, personnel controls, and confined-space practices are governed by the project site's approved lifting and safety procedures.

The tower internals supplier should provide accurate:

• dimensions;
• weight;
• center-of-gravity information where required;
• lifting-point information.

Site lifting execution remains subject to approved project procedures.

Engineering Takeaway

Installation feasibility requires:

Segment Size + Weight + Stiffness + Center of Gravity + Manway Path + Lifting Point + Assembly Sequence

The key question is not merely:

Can the component fit through the manway?

It is:

Can it be handled from the shipping crate all the way to its installed position without damaging the internal?