How to Write an RFQ for Ceramic Grid Packing
Ceramic grid packing is not a commodity that can always be quoted accurately from:
“Need 5 m³ ceramic grid.”
The supplier needs to understand both:
- module geometry;
- process duty.
A complete RFQ reduces repeated questions and prevents a physically fitting but hydraulically unsuitable product from being quoted.
1. State the Application
Describe the equipment:
- absorber;
- scrubber;
- gas-treatment tower;
- other process tower.
This provides context for the required packing function.
2. Identify the Process Chemistry
Provide:
- gas components;
- liquid components;
- concentration where relevant.
Ceramic material must be chemically compatible before geometry is considered.
3. Give Operating Temperature
State:
- normal temperature;
- maximum upset temperature.
This helps confirm ceramic grade and mechanical arrangement.
4. Provide Tower Diameter or Cross-Section
Grid packing must fit the vessel.
For a round tower, provide:
- internal diameter.
For a rectangular chamber, provide:
- length;
- width.
5. Provide Required Bed Height
This determines:
- total number of layers;
- approximate quantity.
If the height is not yet fixed, provide the process duty so engineering review can continue.
6. Existing Module Dimensions
For replacement service, provide:
- length;
- width;
- height.
Measure several pieces.
7. Grid Pitch
Provide the repeating center spacing or other relevant grid dimension.
If unknown, detailed photographs with measurements can help.
8. Clear Opening
Measure the unobstructed passage.
This is critical for:
- fouling tolerance;
- pressure drop.
9. Rib Thickness
Include structural wall thickness if possible.
This helps evaluate:
- weight;
- open area;
- equivalence.
10. Module Weight
One intact sample weight provides useful information.
For old unknown media, this can help distinguish significantly different designs.
11. Gas Flow
Provide:
- normal;
- maximum gas flow.
Hydraulic capacity cannot be evaluated from geometry alone.
12. Liquid Flow
For gas-liquid contact towers, include liquid circulation rate.
Wet pressure drop and mass-transfer behavior depend on both phases.
13. Fouling Information
This is one of the most valuable RFQ details.
State whether the process contains:
- solids;
- crystals;
- sticky material;
- scale.
If possible, provide:
- particle size;
- concentration.
The reason for using grid packing may depend entirely on this information.
14. Pressure-Drop Requirement
If the project has a maximum acceptable bed ΔP, state it.
This helps determine whether the geometry is sufficiently open.
15. Mass-Transfer Requirement
Where available, provide:
- inlet composition;
- outlet target.
Grid packing should not be selected only from hydraulic requirements if process performance must also be guaranteed.
16. Existing Bed Performance
For replacement projects, provide historical:
- pressure drop;
- capacity;
- fouling interval.
This gives valuable evidence about the current design.
17. Support Information
Provide:
- support-bar spacing;
- support drawing;
- photograph.
The grid modules need safe and open bearing.
18. Layer Orientation
If replacing an existing structured bed, document:
- orientation;
- rotation sequence.
Do not lose this information during demolition.
19. Access Size
Provide:
- manway dimensions
if modules must pass through an existing tower opening.
A module that cannot enter the vessel is not a useful design.
20. Packaging Requirement
Large ceramic modules usually need stronger protection than ordinary random packing.
State any site or transport requirements.
21. Required Documentation
Possible documents include:
- TDS;
- material composition;
- dimensions;
- chemical-resistance data;
- inspection report.
Do not request irrelevant certificates merely because another project used them.
22. Quantity Basis
For grid modules, quantity may be best defined by:
- number of pieces;
- layer arrangement;
- total bed volume.
Avoid relying only on approximate tonnage.
23. Spares
For custom modules, consider intentional spare pieces.
The spare quantity should be agreed—not hidden inside a vague quantity allowance.
24. Replacement Sample
If technical information is missing, send:
- intact sample;
- complete measurements.
A sample can greatly reduce reverse-engineering uncertainty.
25. State the Real Problem
If the existing packing is being replaced because of:
- plugging;
- excessive ΔP;
- cracking,
say so.
A good supplier should know whether the goal is:
duplicateorimprove.
Engineering Takeaway
The most useful ceramic grid RFQ combines geometry, chemistry, hydraulics and installation data.a