Selecting tower packing is not simply a matter of choosing a material, nominal size, or packing shape.
A useful preliminary recommendation depends on understanding how the tower will actually operate.
For many packed-column projects, the most important information includes:
Tower internal diameter
Gas flow
Liquid flow
Operating temperature
Operating pressure
Gas composition
Liquid composition
Process duty
Packing bed height
Fouling or solids information
Allowable pressure drop
Existing packing information for replacement projects
The more complete the operating data, the more meaningful the preliminary packing screening can be.
DAIER Separation Technology uses available process conditions, tower dimensions, material requirements, and DAIER Factory Reference Data to support preliminary packing selection and project-data preparation.
Why Is Project Data Important?
Tower packing works as part of a complete gas-liquid contacting system.
Its performance depends on the relationship between:
Gas load + Liquid load + Tower geometry + Packing geometry + Fluid properties + Process requirements
Two customers may ask for the same nominal packing size but require completely different solutions because their process conditions are different.
For example:
One tower may operate under vacuum
Another may operate at elevated pressure
One process may be clean
Another may contain solids or crystallizing material
One project may prioritize low pressure drop
Another may prioritize corrosion resistance
One tower may be a new design
Another may be a replacement inside an existing vessel
This is why a packing recommendation based only on a product name or tower diameter can be incomplete.
1. Tower Internal Diameter
Tower internal diameter is one of the first dimensions required for preliminary screening.
It affects:
Tower cross-sectional area
Gas velocity
Liquid loading per unit area
Packing-size suitability
Wall effects
Liquid distribution
Installation requirements
For the same gas flow, a smaller tower diameter creates a higher superficial gas velocity.
For the same liquid flow, a smaller diameter also creates a higher liquid load per unit area.
Tower diameter therefore provides important context for both gas-side and liquid-side hydraulic screening.
2. Gas Flow Rate
Gas flow is required to understand the gas load passing through the packed bed.
Useful gas-flow information may be provided as:
Actual m³/h
Nm³/h
Sm³/h
kg/h
CFM
SCFM
Other clearly defined flow units
The flow basis should always be identified.
A normalized gas-flow value should not automatically be treated as the actual gas volume inside the operating tower.
Temperature and pressure can significantly change actual gas volume.
For this reason, gas flow should be reviewed together with operating temperature, pressure, and tower diameter.
For more information, see:
How Gas Velocity Affects Tower Packing Selection
https://www.pxdaier.com/tower-packing-solutions/how-gas-velocity-affects-tower-packing-selection
3. Liquid Flow Rate
Liquid flow is equally important.
In many packed towers, gas moves upward while liquid flows downward through the same packing passages.
Liquid loading affects:
Wetting
Liquid holdup
Pressure-drop tendency
Drainage
Hydraulic capacity
Flooding margin
Distributor requirements
A packing selected from gas flow alone may not provide a reliable engineering direction.
For preliminary screening, provide the actual liquid circulation or process flow whenever possible.
For more information, see:
How Liquid Loading Affects Tower Packing Selection
https://www.pxdaier.com/tower-packing-solutions/how-liquid-loading-affects-tower-packing-selection
4. Operating Temperature
Operating temperature can influence both material selection and hydraulic conditions.
For example, temperature may affect:
Plastic material suitability
Chemical compatibility
Gas volume
Gas density
Liquid viscosity
Process stability
A packing material that is suitable at ambient temperature may not be suitable at a much higher process temperature.
Temperature should therefore be provided before finalizing material direction.
5. Operating Pressure
Operating pressure affects gas density and actual gas volume.
This becomes particularly important in:
Vacuum towers
Pressurized absorbers
Distillation columns
High gas-throughput systems
A tower operating under vacuum may place much greater emphasis on low pressure drop than a system operating under different conditions.
Pressure should therefore be included in preliminary project data whenever available.
6. Gas Composition
Gas composition helps engineers understand:
Process duty
Corrosion risk
Temperature limitations
Chemical compatibility
Possible solids or contaminants
Safety-related material considerations
For example, a general statement such as:
“Chemical gas”
is not enough for useful material screening.
Whenever possible, identify the major gas components and any corrosive or reactive substances.
7. Liquid Composition
Liquid composition is especially important for packing-material selection.
Typical packing materials may include:
PP
PE
PVDF
PTFE
Stainless steel
Carbon steel
Ceramic
The correct material depends on the actual chemical environment.
Useful liquid information may include:
Main chemical
Concentration
pH where relevant
Temperature
Solids content
Chloride or corrosive components where applicable
Cleaning chemicals
Material selection should never be based on temperature alone.
For more information, see:
How to Select Tower Packing Material
https://www.pxdaier.com/tower-packing-solutions/how-to-select-tower-packing-material
8. Process Duty
The purpose of the tower should be clearly identified.
Common packed-tower duties include:
Absorption
Stripping
Scrubbing
Distillation
Gas washing
Acid-gas treatment
VOC treatment
Cooling or humidification
Other gas-liquid contacting processes
Different duties can place different priorities on:
Pressure drop
Mass-transfer efficiency
Fouling resistance
Material
Liquid distribution
Packing geometry
The same packing should not automatically be recommended for every process simply because the tower diameter is similar.
9. Packing Bed Height
Packing bed height is required for several practical reasons.
It can influence:
Total packing volume
Packing quantity
Packing weight
Total packed-bed pressure drop
Support requirements
Redistribution strategy
A project may have one packed section or several sections separated by liquid redistributors.
For quantity calculation:
Packing Volume = Tower Cross-Sectional Area × Packing Height
If bed height is known, the DAIER Tower Packing Engineering Assistant can help calculate preliminary packing volume and estimate packing weight.
For more information, see:
How to Calculate Tower Packing Volume
https://www.pxdaier.com/tower-packing-solutions/calculate-tower-packing-volume
and:
How to Calculate Tower Packing Weight
https://www.pxdaier.com/tower-packing-solutions/calculate-tower-packing-weight
10. Fouling, Solids, and Crystallization Risk
Dirty service requires additional attention.
Tell the packing supplier if the process contains:
Suspended solids
Dust
Scale
Crystallizing salts
Sticky materials
Polymerizing compounds
Corrosion products
Coke
Other deposits
Fouling can gradually reduce packing open area and increase hydraulic resistance.
A packing with high specific surface area may not be the best choice if the flow passages are too restrictive for the actual fouling condition.
For fouling-sensitive service, preliminary selection may place greater emphasis on:
Open geometry
Larger flow passages
Packing size
Cleanability
Washing strategy
Maintenance access
For more information, see:
How Fouling Affects Tower Packing Selection
https://www.pxdaier.com/tower-packing-solutions/how-fouling-affects-tower-packing-selection
11. Allowable Pressure Drop
Some applications have strict pressure-drop limitations.
This is particularly important in:
Vacuum service
Blower-limited systems
Compressor-limited systems
High gas-flow towers
Tower revamps
Energy-sensitive processes
If there is a maximum allowable pressure drop, it should be provided during the packing review.
Packing size, geometry, bed height, gas load, and liquid load all influence hydraulic resistance.
For more information, see:
How Packing Size Affects Pressure Drop in a Packed Tower
https://www.pxdaier.com/tower-packing-solutions/how-packing-size-affects-pressure-drop
12. Existing Packing Information for Replacement Projects
Replacement projects require more information than new installations.
Useful existing-tower data include:
Existing packing type
Existing packing size
Existing material
Packing bed height
Tower diameter
Current gas flow
Current liquid flow
Existing pressure drop
Existing operating problems
Fouling condition
Packing damage
Required replacement objective
The replacement objective is especially important.
For example, is the customer trying to:
Replace damaged packing?
Reduce pressure drop?
Increase capacity?
Improve fouling resistance?
Change material?
Solve flooding?
Replace an obsolete model?
Maintain the same process performance?
Without knowing the problem, repeating the existing packing may simply repeat the same operating issue.
What Additional Data May Be Needed?
Depending on the project, detailed engineering review may also require:
Gas density
Liquid density
Liquid viscosity
Surface tension
Molecular weight
Required separation efficiency
Mass-transfer requirement
Feed composition
Product specification
Existing HETP data
Distributor information
Support-plate information
Packing hold-down arrangement
Manway dimensions
Installation limitations
Not every preliminary inquiry needs all of these data.
However, they may become necessary before final hydraulic or process-performance confirmation.
Minimum Data for Preliminary Screening
If the customer cannot provide a complete process datasheet, start with the most important available information.
Minimum Project Data
Purpose
Tower internal diameter
Establishes tower area
Gas flow
Indicates gas loading
Liquid flow
Indicates liquid loading
Temperature
Supports hydraulic and material screening
Pressure
Supports actual gas-condition review
Gas composition
Supports process and corrosion review
Liquid composition
Supports material screening
Process duty
Defines project objective
Packing height
Supports quantity calculation
Fouling information
Helps identify geometry direction
This information can support preliminary screening.
It does not replace a complete hydraulic design.
Data Required for a New Packed Tower
For a new tower project, provide:
Process duty
Gas flow
Liquid flow
Gas composition
Liquid composition
Temperature
Pressure
Proposed tower diameter, if available
Required packing height, if available
Material requirements
Pressure-drop limitations
Fouling conditions
If tower diameter has not yet been determined, detailed hydraulic design may be required before final equipment dimensions are confirmed.
Data Required for a Packing Replacement
For a replacement project, provide:
Existing tower diameter
Existing packing type
Existing packing size
Existing material
Existing packing height
Gas flow
Liquid flow
Temperature
Pressure
Current operating problem
Fouling condition
Photos of existing packing if available
Drawings or datasheets if available
This allows the replacement to be reviewed against actual operating needs rather than simply copying the original packing.
Data Required for a Tower Revamp
Tower revamps require both current and future operating conditions.
Useful information includes:
Current Condition
New Condition
Current gas flow
Target gas flow
Current liquid flow
Target liquid flow
Current packing
Proposed replacement direction
Current pressure drop
Required pressure-drop target
Current capacity
Target capacity
Current operating problems
Revamp objective
This comparison helps identify whether packing replacement may provide a useful direction or whether the tower itself has a broader hydraulic limitation.
Why Product Name Alone Is Not Enough
An inquiry such as:
“Please quote 50 mm Pall Rings.”
is enough to request a price.
It is not enough to confirm whether 50 mm Pall Rings are the best choice for the process.
Similarly:
“We need PP packing.”
provides material direction but does not confirm:
Correct packing size
Correct geometry
Hydraulic suitability
Fouling suitability
Required quantity
Operating margin
For a commercial quotation, product dimensions and quantity may be sufficient.
For engineering screening, process information is necessary.
Why Preliminary Screening Is Not Final Hydraulic Design
A preliminary engineering assistant can help organize data and identify possible packing directions.
However, final hydraulic design may require detailed calculations for:
Pressure drop
Flooding
Loading
Hydraulic capacity
Tower diameter
Mass transfer
HETP
Distribution requirements
Operating margin
For example, flooding cannot be determined from gas velocity alone.
It depends on the complete gas-liquid system.
For more information, see:
What Causes Flooding in a Packed Tower?
https://www.pxdaier.com/tower-packing-solutions/what-causes-flooding-in-a-packed-tower
Use the DAIER Tower Packing Engineering Assistant
The DAIER Tower Packing Engineering Assistant helps users organize preliminary project information before engineering review.
The tool can support:
Random packing screening
Structured packing screening
Material-direction screening
Packing-size comparison
Catalog-model comparison
Packing-volume calculation
Packing-weight estimation
Preliminary engineering report preparation
When complete operating data are not available, the tool keeps the result at a preliminary material, structure, or product-family level instead of presenting an unsupported exact model.
Prepare your project data and screen a preliminary packing direction:
https://www.pxdaier.com/tower-packing-engineering-assistant.html
Tower Packing RFQ Checklist
Before sending a tower packing inquiry, prepare the following information whenever possible:
Tower Information
Tower internal diameter
Packing bed height
Number of packed sections
Existing internals
Manway or installation limitations
Gas Information
Gas flow
Flow basis
Gas composition
Temperature
Pressure
Liquid Information
Liquid flow
Liquid composition
Density if available
Viscosity if available
Solids or fouling information
Packing Requirement
Random or structured packing if already specified
Preferred material
Existing packing model
Existing packing size
Required quantity if known
Project Objective
New tower
Replacement
Capacity increase
Pressure-drop reduction
Fouling improvement
Material upgrade
Maintenance replacement
A complete RFQ allows the supplier and engineer to respond more efficiently and reduces unnecessary back-and-forth communication.
Frequently Asked Questions
What is the minimum information needed to select tower packing?
For preliminary screening, tower diameter, gas flow, liquid flow, temperature, pressure, process duty, and fluid composition are among the most useful data.
Additional information may be required for final engineering confirmation.
Can DAIER recommend packing if I only know the tower diameter?
Only a very preliminary product direction may be possible.
Tower diameter alone does not provide enough information to confirm hydraulic suitability.
Do I need both gas flow and liquid flow?
Yes, whenever possible.
Both phases affect pressure drop, loading, flooding margin, wetting, and hydraulic capacity.
What information is needed for a packing replacement?
Provide the existing packing type, size, material, bed height, tower diameter, operating conditions, current problem, and any available drawings or photos.
Can I request a quotation without complete process data?
Yes.
If the required packing model, size, material, and quantity are already specified, a commercial quotation may be possible.
However, this does not mean the specified packing has been hydraulically verified for the process.
Why does DAIER not always recommend an exact model automatically?
When important operating data are missing, presenting an exact model could imply a level of engineering certainty that the available information does not support.
In those cases, preliminary screening should remain at a material, structure, or product-family level.
What data is needed to calculate packing quantity?
Tower internal diameter and packing bed height are the main dimensions needed for preliminary packing-volume calculation.
Packing bulk density or model data can then support weight estimation.
Engineering Limitation
This article is intended for preliminary tower-packing screening, RFQ preparation, and project-data organization.
DAIER Factory Reference Data and catalog-confirmed reference parameters can support preliminary comparison, but they do not constitute project-specific pressure-drop, flooding, hydraulic-capacity, HETP, mass-transfer, or performance guarantees.
Final tower packing selection may require complete operating data, physical properties, tower geometry, liquid-distribution information, packing-specific hydraulic data, fouling conditions, and detailed engineering calculations.
Final hydraulic and process performance should be confirmed through project-specific engineering review.
Pingxiang Daier Separation Tech Co., Ltd.DAIER Separation Technology
Manufacturer since 2009 | Preliminary Engineering Support | Custom Manufacturing