How to Use the DAIER Tower Packing Engineering Assistant for an Existing Tower Replacement
Replacing packing in an existing tower is different from selecting packing for a completely new column.
In a new project, engineers may still have flexibility to change:
tower diameter
packing bed height
packing type
liquid distributor
support internals
operating conditions
In an existing tower, many of these conditions are already fixed.
The real question is usually:
What packing can work within the existing tower constraints—and why does the current packing need to be replaced?
The DAIER Tower Packing Engineering Assistant can help organize existing tower data, calculate packing quantity and screen preliminary replacement directions before a detailed engineering review.
[Use the DAIER Tower Packing Engineering Assistant → https://www.pxdaier.com/tower-packing-engineering-assistant.html]
Why Existing Tower Replacement Requires a Different Approach
A replacement project should not begin by asking only:
“What is the equivalent replacement for my current packing?”
Before selecting a replacement, identify the actual project objective.
Common reasons for replacing tower packing include:
damaged packing
corrosion
fouling or blockage
excessive pressure drop
insufficient capacity
repeated flooding
poor separation performance
material incompatibility
process-condition changes
an obsolete packing model
planned tower revamp
Simply copying the old packing specification can reproduce the same operating problem.
The first task is therefore to understand why the existing packing is being replaced.
Step 1 — Enter the Existing Tower Diameter
For an existing tower, use the actual internal diameter (ID) of the packing section.
Do not use only the vessel outside diameter.
The tower diameter affects:
packing quantity
gas velocity
packing-size suitability
wall effects
distributor arrangement
hydraulic capacity
If the tower has different diameters in different sections, each packed section should be reviewed separately.
For more detail:
[How Tower Diameter Affects Tower Packing Selection → https://www.pxdaier.com/tower-packing-solutions/how-tower-diameter-affects-packing-selection]
Step 2 — Enter the Existing Packing Bed Height
Record the actual packed-bed height.
If the tower contains more than one bed, list each bed separately.
For example:
Bed 1: 2.5 m
Bed 2: 3.0 m
Bed 3: 2.0 m
Tower diameter and bed height allow the preliminary packing volume to be calculated.
For a cylindrical bed:
Packing Volume = π × D² / 4 × H
where:
D = tower internal diameter
H = packing bed height
The result provides the approximate volume required for the replacement bed.
Step 3 — Record the Existing Packing
The existing packing is one of the most valuable pieces of information in a replacement project.
Provide, if available:
packing type
packing size
packing material
manufacturer or model
approximate installation date
packing bulk density
packing photographs
condition after removal
Examples may include:
50 mm PP Pall Ring
38 mm ceramic Intalox Saddle
metal random packing
structured packing
an older proprietary packing model
If the exact model is unknown, photographs and dimensions can still help establish a preliminary direction.
Step 4 — Record the Current Operating Conditions
A replacement recommendation should be based on current process conditions—not only the original tower design.
Useful data include:
gas flow
liquid flow
operating temperature
operating pressure
gas composition
liquid composition
density
viscosity
solids or contaminants
normal operating range
maximum operating conditions
This is especially important if production capacity or process conditions have changed since the tower was originally built.
For the full input checklist:
[Tower Packing Selection Parameters → https://www.pxdaier.com/tower-packing-solutions/tower-packing-selection-parameters]
Step 5 — Define the Replacement Objective
Before comparing new packing, define what the project is trying to improve.
Objective A — Replace Damaged Packing
If the existing packing is mechanically damaged but tower performance was otherwise acceptable, the project may initially look for:
the same packing type
the same size
the same material
a technically comparable replacement
However, the reason for the damage should still be reviewed.
Objective B — Reduce Pressure Drop
If the existing tower has excessive pressure drop, investigate whether the problem is caused by:
packing geometry
packing size
excessive gas flow
excessive liquid load
fouling
blocked support internals
distributor problems
Changing packing without identifying the actual restriction may not solve the problem.
See:
[How Pressure Drop Affects Tower Packing Selection → https://www.pxdaier.com/tower-packing-solutions/how-pressure-drop-affects-tower-packing-selection]
Objective C — Improve Fouling Resistance
If the existing packing repeatedly blocks, the replacement review may give more attention to:
larger flow passages
more open geometry
packing size
solids tolerance
cleanability
But the packing should not be blamed automatically.
Also inspect:
liquid distributor
support plate
upstream solids carryover
crystallization
scale formation
See:
[Tower Packing Fouling and Blockage → https://www.pxdaier.com/tower-packing-solutions/tower-packing-fouling-and-blockage]
Objective D — Increase Tower Capacity
A revamp may be required because the plant wants to process more gas or liquid through the existing vessel.
In this case, the tower diameter is fixed.
Increasing throughput can therefore increase hydraulic loading.
The replacement review may need to compare:
current packing
new packing geometry
gas velocity
liquid load
pressure drop
flooding margin
support internals
A packing that physically fits the tower is not automatically suitable for the higher throughput.
Objective E — Change Packing Material
Sometimes the geometry is acceptable, but the existing material is not.
Possible reasons include:
corrosion
temperature increase
chemical change
service-life problems
The project may need to compare:
PP
PE
PVDF
PTFE
SS304
SS316
SS316L
ceramic
other alloys
Material compatibility should be confirmed against the actual operating environment.
Step 6 — Compare Existing and Proposed Packing Size
Do not change packing size only because a different size is cheaper or offers higher catalog surface area.
Packing size affects:
specific surface area
open area
hydraulic resistance
fouling sensitivity
tower-diameter compatibility
For example:
Smaller packing may provide more specific surface area but may also increase pressure drop and blockage sensitivity.
Larger packing may provide more open flow passages but may reduce surface area and may not be appropriate for a small tower.
For more detail:
[How to Choose Tower Packing Size → https://www.pxdaier.com/tower-packing-solutions/how-to-choose-tower-packing-size]
Step 7 — Calculate Replacement Packing Volume
Once the tower diameter and bed height are confirmed, the Engineering Assistant can help establish the preliminary packing volume.
This is useful for:
quotation
quantity planning
packing weight estimation
freight planning
installation planning
However, the calculated geometric volume is not automatically the final purchase quantity.
The final project may also consider:
installation allowance
multiple beds
damaged-piece allowance
actual usable tower dimensions
project-specific requirements
Step 8 — Estimate Packing Weight
Packing weight depends on:
Packing Volume × Packing Bulk Density
The same tower volume can require very different total weights depending on the selected packing.
For example:
plastic packing
stainless steel packing
ceramic packing
have very different bulk densities.
Therefore, final packing weight should be calculated only after the actual replacement model is identified.
This information is useful for:
support-load review
packing handling
freight calculation
installation planning
Step 9 — Check the Existing Packing Support
Before ordering replacement packing, inspect or confirm the existing support system.
Useful information includes:
support plate type
support grid type
opening size
open area
material
corrosion condition
deformation
current load capacity
Changing packing may change:
total bed weight
hydraulic load
individual packing size
support requirements
Do not assume the existing support is automatically suitable for every replacement packing.
Step 10 — Check the Hold-Down Arrangement
Some packing beds require a retaining or hold-down arrangement.
Confirm whether the existing tower has:
hold-down grid
retaining ring
bed limiter
other packing restraint
This becomes important where packing movement may occur because of:
high gas velocity
upset conditions
lightweight plastic packing
tower vibration
If the replacement packing has significantly different density or geometry, the existing hold-down system should be reviewed.
Step 11 — Check the Liquid Distributor
A replacement packing cannot correct severe liquid maldistribution.
Before blaming the old packing, check the distributor if possible.
Review:
distributor type
blockage
corrosion
damaged holes
uneven irrigation
liquid-flow range
turndown
If the distributor is unsuitable, installing new packing below it may reproduce the same performance problem.
For a major revamp, the packing and distributor should be reviewed as part of the same system.
Step 12 — Check Manway and Installation Restrictions
This is often overlooked until the order is already placed.
For replacement projects, confirm:
manway diameter
internal access
installation direction
lifting limitations
packing block dimensions
available working space
Random packing can normally be loaded as individual elements.
Structured packing and large tower internals may need to be manufactured in segments so they can pass through the manway.
Installation access should therefore be confirmed before final production.
Step 13 — Compare the Tool Result with the Existing Problem
After entering the available tower and operating information, do not read the Engineering Assistant result in isolation.
Compare it directly against the project objective.
For example:
Existing Problem: High Pressure Drop
Ask:
Does the proposed direction provide a more open geometry?
Is the packing size suitable?
Is fouling actually causing the pressure drop?
Existing Problem: Blockage
Ask:
Does the proposed packing provide larger passages?
Are solids still entering the tower?
Is the distributor also blocked?
Existing Problem: Low Capacity
Ask:
Has gas throughput increased?
Has liquid loading increased?
Is the existing tower diameter now limiting capacity?
Existing Problem: Corrosion
Ask:
Is the replacement material compatible with the current process?
Have concentration or temperature changed?
This is how the tool becomes useful for revamp screening rather than simply generating a product suggestion.
Step 14 — Do Not Assume an “Equivalent Packing” Is Truly Equivalent
Replacement RFQs often ask for:
“Equivalent to existing packing.”
But two packings with similar nominal dimensions can still differ in:
geometry
specific surface area
void fraction
bulk density
hydraulic behavior
mechanical strength
An equivalent replacement should therefore be reviewed using both:
physical compatibility + process compatibility
rather than only nominal size.
Step 15 — Use Old Operating Data When Available
Existing towers provide something new projects do not always have:
real operating history.
Useful information may include:
actual pressure drop
actual throughput
operating stability
flooding history
fouling frequency
cleaning interval
packing service life
This information can be extremely useful during preliminary replacement screening.
If the old tower operated successfully for many years, that history should not be ignored.
If the old tower repeatedly failed, the reason should be identified before duplicating the old packing.
Step 16 — Photographs Can Help
For existing towers, useful photographs may include:
removed packing
packing fouling
packing damage
support plate
hold-down grid
liquid distributor
tower interior
manway
Photographs do not replace process data, but they can help identify:
packing geometry
physical damage
fouling pattern
installation arrangement
access restrictions
This can reduce unnecessary back-and-forth during the RFQ stage.
Replacement Project Data Checklist
Before using the Engineering Assistant for an existing tower, prepare as much of the following as possible:
Tower
Internal diameter
Packing bed height
Number of beds
Manway size
Existing Packing
Type
Size
Material
Model, if known
Bulk density, if known
Photographs
Process
Gas flow
Liquid flow
Temperature
Pressure
Gas composition
Liquid composition
Solids or fouling
Existing Performance
Pressure drop
Capacity
Flooding history
Fouling history
Service life
Current operating problem
Tower Internals
Liquid distributor
Support plate or support grid
Hold-down system
Redistributor, if any
Project Objective
Same replacement
Lower pressure drop
Higher capacity
Better fouling resistance
Material upgrade
Efficiency improvement
How to Use the Tool for a Replacement Project
A practical workflow is:
1. Enter the existing tower dimensions
Use the actual tower ID and packing bed height.
2. Enter available operating data
Add gas flow, liquid flow, temperature, pressure and process information.
3. Record the current packing
Identify the existing packing type, size and material.
4. Define the problem
Explain why the packing is being replaced.
5. Review the preliminary direction
Compare possible packing family, size and material directions.
6. Calculate replacement quantity
Estimate packing volume and preliminary weight.
7. Prepare the RFQ
Send the result together with drawings, photographs and existing operating data.
What the Engineering Assistant Cannot Replace
The DAIER Tower Packing Engineering Assistant supports preliminary replacement screening.
A final tower revamp may still require:
detailed hydraulic calculation
flooding evaluation
pressure-drop calculation
mass-transfer evaluation
process simulation
distributor design
mechanical verification
support-load calculation
installation drawings
This becomes especially important when the project aims to:
increase capacity
significantly change packing type
change bed height
modify tower internals
operate closer to hydraulic limits
Use the DAIER Tower Packing Engineering Assistant
Use the [DAIER Tower Packing Engineering Assistant → https://www.pxdaier.com/tower-packing-engineering-assistant.html] to organize preliminary data for an existing tower packing replacement or revamp project.
The tool can help you:
organize existing tower dimensions
review available operating conditions
screen packing direction
compare packing size
calculate packing volume
estimate packing weight
identify missing project information
prepare a more complete RFQ
If you are using the tool for the first time:
[How to Use the DAIER Tower Packing Engineering Assistant → https://www.pxdaier.com/tower-packing-solutions/how-to-use-the-daier-tower-packing-engineering-assistant]
To understand the tool output:
[How to Interpret Tower Packing Engineering Assistant Results → https://www.pxdaier.com/tower-packing-solutions/how-to-interpret-tower-packing-engineering-assistant-results]
For replacement projects, the most important principle is simple:
Do not replace the old packing until you understand why it needs to be replaced.
Use the tool to organize the evidence first, then confirm the final packing and tower-internals requirements according to the actual project conditions.
Specs and test data available upon request.