Ceramic Raschig Ring Replacement: What Must Be Matched Before Ordering?

Ceramic Raschig Ring replacement should not be specified by nominal size alone. For a true maintenance replacement, the buyer should identify the existing ring dimensions, wall thickness, ceramic quality, packed-bed physical properties, tower dimensions, support arrangement and the reason the old packing is being removed.

DAIER's catalog-aligned Ceramic Raschig Ring data show that nominal size is only one part of the specification. Across the available series, surface area, void fraction, bulk density, packing population and dry packing factor vary substantially—and some parameters are not even monotonic with size. 

The main procurement rule is:

If the existing tower works well, replacement should reproduce the proven ceramic packing as closely as practical.

If the buyer intentionally changes:

• size;
• ceramic composition;
• geometry;
• bed height;

the project is no longer a simple replacement.

It becomes an engineering retrofit.

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1. Direct Answer

Before ordering replacement Ceramic Raschig Rings, confirm:

• nominal size;
• actual outside diameter;
• ring height;
• wall thickness;
• ceramic composition or grade if available;
• specific surface area;
• void fraction;
• bulk density;
• pieces per cubic meter;
• dry packing factor;
• tower internal diameter;
• packed height;
• number of beds;
• packing support details;
• reason for replacement.

For ceramic products, also request project-relevant quality data such as:

• chemical-resistance properties;
• mechanical-strength information;
• dimensional tolerance;
• inspection criteria.

Do not assume that two products called:

“Ceramic Raschig Ring 50 mm”

are automatically equivalent.

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2. DAIER Ceramic Raschig Ring Series

DAIER's catalog-aligned dataset includes sizes from approximately 6 to 100 mm. The 6, 13 and 16 mm entries already show how strongly bed properties change as size changes.

The 19–80 mm values and the 100 mm catalog record confirm that several parameters do not move in a simple straight line with increasing size.

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3. First Decide: Replacement or Retrofit?

This distinction controls the whole project.

Routine Replacement

The goal is:

• restore the existing tower;
• preserve proven performance;
• replace damaged or aged packing.

Normally match:

• packing family;
• ceramic type;
• nominal size;
• actual dimensions;
• physical properties.

Engineering Retrofit

The goal is to improve or change:

• pressure drop;
• capacity;
• fouling behavior;
• mass-transfer duty;
• mechanical loading.

Then the project may intentionally change:

• size;
• packing family;
• material.

Those decisions require engineering review.

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4. Why Nominal Size Alone Is Not Enough

Suppose the RFQ says:

Ceramic Raschig Ring 50 mm

That does not fully tell the supplier:

• actual ring height;
• wall thickness;
• ceramic composition;
• surface area;
• void fraction;
• bulk density.

DAIER's catalog-aligned 50 mm model is approximately:

• 92 m²/m³ surface area;
• 74% void fraction;
• 600 kg/m³ bulk density;
• 5,792 pcs/m³;
• 213 m⁻¹ packing factor;
• approximately 6 mm wall thickness. 

If another 50 mm product differs materially from these properties:

it should not automatically be treated as a like-for-like replacement.

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5. Actual Ring Dimensions Matter

Ceramic Raschig Rings are fundamentally defined by:

• outside diameter;
• height;
• wall thickness.

The DAIER catalog-aligned database includes verified thickness values such as:

• 6 mm model — approximately 1.6 mm;
• 13 mm — approximately 2.4 mm;
• 16 mm — approximately 2.5 mm;
• 25 mm — approximately 3 mm;
• 38 mm — approximately 5 mm;
• 50 mm — approximately 6 mm;
• 80 mm — approximately 9.5 mm. 

Wall thickness strongly affects:

• solid volume;
• ring strength;
• packed-bed weight;
• flow opening.

So it should be checked in replacement procurement.

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6. Why Wall Thickness Is Especially Important for Ceramic Packing

Ceramic is brittle.

A ring wall must provide sufficient mechanical integrity for:

• handling;
• shipment;
• loading;
• packed-bed service.

But thicker ceramic also occupies more solid volume.

Therefore:

wall thickness is part of both the mechanical and hydraulic specification.

Two rings with the same outside diameter but different wall thickness can create different:

• void fraction;
• kg/m³;
• flow passages.

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7. Surface Area Should Be Matched

The catalog series shows a large change in geometric surface area.

For example:

25 mm

190 m²/m³.

50 mm

92 m²/m³.

80 mm

46 m²/m³.

Moving from 25 to 50 mm reduces geometric surface-area density by more than half.

Therefore:

changing size during replacement can materially alter mass-transfer potential.

Do not increase size only because larger rings look more open.

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8. Void Fraction Must Also Be Checked

The verified values include:

• 25 mm — 74%;
• 38 mm — 73%;
• 40 mm — 75%;
• 50 mm — 74%;
• 80 mm — 80%;
• 100 mm — 70%. 

This is clearly non-monotonic.

The 100 mm model does not have the highest published void fraction.

So the assumption:

“larger Ceramic Raschig Ring always means more voidage”

is false for this supplier-specific series.

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9. 80 mm vs 100 mm Is a Good Warning Example

DAIER's verified data show:

80 mm

• 46 m²/m³;
• 80% void;
• 660 kg/m³;
• 1,953 pcs/m³;
• 280 m⁻¹.

100 mm

• 70 m²/m³;
• 70% void;
• 600 kg/m³;
• 1,000 pcs/m³;
• 172 m⁻¹. 

Increasing nominal size gives:

• fewer pieces;
• lower packing factor;

but also:

• lower void fraction;
• higher surface area.

This is exactly why:

replacement data should come from the actual supplier model—not from a simple size trend.

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10. Bulk Density Is Critical for Ceramic Replacement

Ceramic packing is heavy.

Verified dry bulk density includes:

• 25 mm — 650 kg/m³;
• 38 mm — 650 kg/m³;
• 50 mm — 600 kg/m³;
• 80 mm — 660 kg/m³;
• 100 mm — 600 kg/m³. 

Notice again:

80 mm is heavier per cubic meter than 50 mm.

So:

larger ceramic packing is not automatically lighter.

Use actual kg/m³ values.

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11. Why Bulk Density Matters for Replacement Quantity

Suppose the tower contains:

15 m³ of 50 mm Ceramic Raschig Ring.

Using the catalog dry density:

15 × 600 =

9,000 kg

of theoretical dry packing.

For 80 mm:

15 × 660 =

9,900 kg.

The larger packing would actually create:

900 kg more dry load

for the same packed volume.

That can matter for:

• support grids;
• support beams;
• shipping;
• handling.

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12. Packing Support Load Must Be Reviewed

Ceramic random packing imposes significant dead load.

During replacement, inspect:

• packing support;
• beams;
• clips;
• welds;
• corrosion condition.

A damaged support should not simply be reloaded because:

“it held the old packing before.”

The old structure may have:

• corroded;
• deformed;
• lost capacity.

For a true retrofit involving heavier packing, structural review becomes even more important.

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13. Operating Load Is Higher Than Dry Packing Weight

Dry bulk density is only one load component.

The support system may also carry:

• liquid holdup;
• deposits;
• fouling material;
• dynamic loading.

Therefore:

catalog kg/m³ should not be treated as the final support-design load.

It is the dry packing contribution.

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14. Packing Factor Should Be Compared

DAIER's Ceramic Raschig Ring series includes dry packing factors ranging from:

5249 m⁻¹ at 6 mm

to:

172 m⁻¹ at 100 mm. 

At practical larger sizes:

• 25 mm — 508;
• 38 mm — 312;
• 50 mm — 213;
• 80 mm — 280;
• 100 mm — 172 m⁻¹. 

Again, the trend is not perfectly monotonic because:

80 mm has a higher catalog packing factor than 50 mm.

Exact model data matter.

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15. Packing Factor Is Not Actual Pressure Drop

Do not read:

213 vs 280 m⁻¹

and conclude that operating pressure drop changes by the same ratio.

Actual pressure drop depends on:

• gas velocity;
• liquid load;
• fluid properties;
• tower diameter;
• packed height.

Packing factor is a useful product descriptor.

It is not operating ΔP.

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16. Ceramic Composition Must Be Confirmed

“Ceramic” is not one universal formulation.

Replacement procurement should confirm, where relevant:

• ceramic composition;
• chemical-resistance properties;
• production standard.

This matters because different ceramic formulations can have different resistance to:

• acids;
• alkalis;
• thermal exposure;
• mechanical loading.

Do not assume all ceramic Raschig Rings have identical chemical properties simply because:

• size;
• color;
• shape

look the same.

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17. Acid Resistance and Alkali Resistance Are Separate Properties

A ceramic product can perform strongly in one chemical environment and less strongly in another.

Therefore procurement should not ask only:

“Is this acid-resistant ceramic?”

If the process involves alkaline conditions, also request relevant:

• alkali-resistance data

where required by the project.

Likewise chemical compatibility should be assessed from:

• actual chemical;
• concentration;
• temperature.

Not pH alone.

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18. Do Not Copy Chemical-Resistance Numbers from Another Supplier

Even if two suppliers offer:

25 × 25 mm Ceramic Raschig Ring

their ceramic body formulations may differ.

Therefore supplier A's:

• acid resistance;
• alkali resistance;
• strength

should not automatically be assigned to supplier B's product.

For replacement procurement:

material-property claims should come from the actual proposed supplier or agreed test standard.

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19. Mechanical Strength Should Be Part of Quality Review

Ceramic packing is brittle, so mechanical quality matters.

Where the project requires it, ask the supplier for the appropriate:

• crushing-strength;
• compressive-strength;
• breakage-related

test information applicable to the exact product.

Do not invent one universal minimum value for every Ceramic Raschig Ring size.

Strength can vary with:

• size;
• wall thickness;
• ceramic formulation;
• test method.

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20. Old Broken Packing Can Distort the Replacement Assessment

During shutdown, old ceramic packing may contain:

• whole rings;
• cracked rings;
• fragments;
• fines.

Do not calculate original packing population simply by counting material removed from the tower.

Breakage changes:

• pieces;
• bed geometry;
• apparent bulk properties.

Use original specifications where available.

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21. Keep Several Intact Samples from the Old Bed

For an old tower with limited records, retain undamaged pieces before disposal.

Measure:

• outside diameter;
• height;
• wall thickness.

Also photograph:

• shape;
• surface condition;
• color.

This can help the replacement supplier identify whether the old packing matches:

• a current standard size;
• a special or obsolete geometry.

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22. Use Multiple Samples, Not One

Ceramic products have manufacturing tolerances.

Old rings can also have:

• chipped edges;
• wear;
• deposits.

Measure several intact pieces and record:

• approximate average;
• observed range.

That is more reliable than building the entire specification around one old ring.

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23. Size Tolerance Should Be Agreed

For large replacement orders, procurement may specify acceptable dimensional tolerance for:

• outside diameter;
• height;
• wall thickness.

The correct tolerance should come from:

• supplier capability;
• applicable product specification;
• project requirement.

Avoid inserting arbitrary ultra-tight tolerances that provide no real engineering benefit.

Ceramic manufacturing is not precision machining.

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24. Breakage During Shipping Should Be Controlled

Ceramic packing can be damaged by:

• impact;
• rough handling;
• poor packaging.

Therefore ask for:

• packing method;
• package type;
• net weight;
• gross weight;
• package dimensions.

For major orders, the buyer may also define:

• inspection method;
• allowable damaged material approach

as agreed commercially.

Do not wait until the tower shutdown to discover extensive transport damage.

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25. Packaging Must Match the Installation Method

Ceramic Raschig Rings may be supplied in:

• bags;
• cartons;
• crates;
• other project-specific packaging.

The choice can affect:

• handling;
• breakage;
• unloading;
• tower filling.

For export orders, packaging should also account for:

• LCL or FCL shipment;
• forklift handling;
• long-distance transport.

Packaging is part of the practical replacement plan.

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26. Confirm the Real Packed Volume

Do not order solely from the previous invoice quantity.

Confirm:

• tower ID;
• bed height;
• number of beds.

The theoretical bed volume is based on tower geometry.

Then account separately for any agreed:

• spare quantity;
• installation allowance.

This prevents confusion between:

required operating volume

and:

commercial order quantity.

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27. Multi-Bed Towers Must Be Recorded Separately

A tower can contain multiple packed sections.

Each bed may differ in:

• packing size;
• packed height;
• service history.

During inspection, record:

Bed 1

• size;
• height;
• condition.

Bed 2

• size;
• height;
• condition.

Do not assume every bed must use the same replacement packing.

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28. Support Grid Opening Must Match the Packing

Changing from a large ring to a smaller ring can create:

• retention problems.

For example, an existing support suitable for:

80 mm packing

may not safely retain:

25 mm packing.

Therefore a size change should trigger review of:

• support opening;
• support geometry;
• open area.

This is another reason why size changes are retrofits.

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29. Check the Manway and Access Route

Individual ceramic rings are small, but the overall replacement project can involve:

• many tonnes of material.

Confirm:

• manway size;
• access platform;
• lifting route;
• removal route.

Installation planning affects:

• labor;
• packaging choice;
• unloading sequence.

A technically correct packing is still difficult to use if the field logistics are ignored.

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30. Do Not Dump Ceramic Packing Carelessly

Because ceramic is brittle, installation method affects breakage.

Packing should be loaded using a controlled procedure that avoids unnecessary:

• free fall;
• impact;
• crushing.

The exact installation method depends on:

• tower size;
• access;
• packing size.

The goal is to preserve the packing geometry that was specified and purchased.

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31. Replacement Due to Breakage Needs Root-Cause Review

If the old tower contains excessive broken ceramic:

simply ordering the same packing may repeat the problem.

Investigate possible contributors such as:

• installation damage;
• support problems;
• mechanical shock;
• abnormal operation;
• maintenance handling.

Only after identifying the cause should the replacement specification be finalized.

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32. Replacement Due to High Pressure Drop May Require More Than New Packing

If pressure drop has increased over time, the cause may be:

• fouling;
• deposits;
• broken ceramic;
• blocked support;
• liquid maldistribution.

New like-for-like packing may restore performance if the problem is contamination or breakage.

But changing size without diagnosing the cause can create a different process problem.

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33. Do Not Automatically Choose a Larger Ring to Reduce Pressure Drop

Compare 25 and 50 mm:

25 mm

• 190 m²/m³;
• 74% void;
• 508 m⁻¹.

50 mm

• 92 m²/m³;
• 74% void;
• 213 m⁻¹. 

The packing factor drops strongly.

But surface area also falls by more than half.

Therefore:

a larger-ring retrofit trades contacting area for a different hydraulic position.

The required process duty must be reviewed.

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34. 50 vs 80 mm Is Even More Counterintuitive

50 mm

• 92 m²/m³;
• 74% void;
• 600 kg/m³;
• 213 m⁻¹.

80 mm

• 46 m²/m³;
• 80% void;
• 660 kg/m³;
• 280 m⁻¹. 

Increasing to 80 mm gives:

• higher voidage;
• fewer pieces;

but also:

• lower surface area;
• heavier bed;
• higher catalog packing factor.

So:

80 mm is not simply a “more open, lower-packing-factor 50 mm.”

That is a very important replacement warning.

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35. Supplier Alternatives Should Be Clearly Marked

A supplier may propose:

• Ceramic Pall Ring;
• saddle-type ceramic packing;
• another ceramic geometry.

That may be technically useful.

But it is no longer:

Ceramic Raschig Ring replacement.

The quotation should distinguish:

Requested

Ceramic Raschig Ring.

Alternative

Different packing geometry.

A geometry change requires separate engineering review.

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36. Compare Quotations by Technical Fields

Use a table such as:

Do not compare only:

price per tonne

or:

price per cubic meter.

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37. Why Price per Ton Can Be Misleading

Tower packing fills:

volume

not simply weight.

Two ceramic products can have different:

• bulk density;
• geometry.

A lower price per tonne can still result in a different:

• cost per packed m³;
• hydraulic bed;
• support load.

For replacement projects, commercial comparison should be connected to:

required packed volume + verified product specification.

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38. Quantity and Weight Should Cross-Check Each Other

If the selected 50 mm product has:

600 kg/m³ catalog bulk density

and the project requires:

10 m³

the theoretical dry packing mass is around:

6,000 kg.

If a supplier quotation shows a drastically different net weight:

ask why.

Possible reasons can include:

• different product geometry;
• different ceramic body;
• different bulk density;
• quantity calculation error.

This is a useful procurement sanity check.

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Ceramic Raschig Ring Replacement Checklist

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39. Quick Replacement Logic

If the old bed performs well:

Match:

same ceramic Raschig Ring geometry + same size + comparable physical data.

If the old packing is heavily broken:

Review:

strength + installation + support + operating history.

If pressure drop is high:

Review:

fouling + support blockage + hydraulics before changing size.

If the process chemistry changed:

Reconfirm:

ceramic composition and chemical resistance.

If the project wants another packing family:

Treat it as:

an engineering retrofit.

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Common Replacement Mistakes

Ordering Only “Ceramic Raschig Ring 50 mm”

Not enough technical information.

Assuming Same Diameter Means Same Product

Wall thickness and ceramic construction matter.

Using Size Alone to Predict Voidage

The DAIER data are non-monotonic.

Assuming Larger Rings Are Always Lighter

80 mm is heavier per m³ than 50 mm in the verified dataset.

Assuming Larger Rings Always Have Lower Packing Factor

80 mm has a higher catalog factor than 50 mm.

Comparing Only Price per Ton

Tower fill is based on volume and geometry.

Ignoring Ceramic Composition

Chemical properties can differ between ceramic bodies.

Copying Another Supplier's Chemical-Test Values

Use data for the actual proposed material.

Ignoring Broken Packing During Inspection

Breakage can distort the old bed.

Changing Size Without Reviewing Surface Area

Mass-transfer characteristics can change substantially.

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Frequently Asked Questions

What should be matched when replacing Ceramic Raschig Rings?

Match the packing family, size, actual dimensions, wall thickness, ceramic quality and key physical bed properties such as surface area, void fraction, bulk density and packing factor.

Is nominal size enough?

No. The same nominal size can be produced with different wall thickness or material properties.

What is DAIER's 25 mm Ceramic Raschig Ring data?

Approximately:

• 190 m²/m³ surface area;
• 74% void fraction;
• 650 kg/m³ bulk density;
• 52,000 pcs/m³;
• 508 m⁻¹ dry packing factor. 

What is the 50 mm data?

Approximately:

• 92 m²/m³;
• 74% void;
• 600 kg/m³;
• 5,792 pcs/m³;
• 213 m⁻¹. 

What is the 80 mm data?

Approximately:

• 46 m²/m³;
• 80% void;
• 660 kg/m³;
• 1,953 pcs/m³;
• 280 m⁻¹. 

Why is 80 mm heavier than 50 mm?

Because actual ceramic wall construction and element geometry determine kg/m³. Nominal diameter alone does not predict bulk density.

Should acid resistance be confirmed?

Yes, when relevant to the service. Use data for the actual proposed ceramic product.

Should alkali resistance also be checked?

Yes when alkaline exposure is part of the process. Acid resistance alone does not define total chemical compatibility.

Can old broken rings be used to identify the original packing?

Intact samples are much more useful. Broken fragments can distort dimensional and population estimates.

Can Ceramic Pall Ring or saddle packing be substituted?

They can be proposed as alternatives, but they should be treated as different packing geometries requiring engineering review.

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Selection Takeaway

Ceramic Raschig Ring replacement is not simply a matter of matching the number printed beside “mm.”

DAIER's verified series demonstrates why:

25 mm → 190 m²/m³ / 74% void / 650 kg/m³ / 52,000 pcs/m³ / 508 m⁻¹

50 mm → 92 m²/m³ / 74% void / 600 kg/m³ / 5,792 pcs/m³ / 213 m⁻¹

80 mm → 46 m²/m³ / 80% void / 660 kg/m³ / 1,953 pcs/m³ / 280 m⁻¹

100 mm → 70 m²/m³ / 70% void / 600 kg/m³ / 1,000 pcs/m³ / 172 m⁻¹.

These values show several important facts:

• larger size does not always mean higher void fraction;
• larger size does not always mean lower bulk density;
• larger size does not always mean lower packing factor;
• wall thickness and ceramic construction matter;
• ceramic quality must be evaluated separately from geometry.

The correct replacement workflow is:

Identify Existing Packing → Measure Intact Rings → Confirm Ceramic Quality → Confirm Tower ID / Bed Height → Compare Physical Data → Inspect Support Grid → Define Required Volume → Confirm Packaging / Inspection → Decide Whether It Is Truly Like-for-Like or a Retrofit

The key principle is:

For a successful old tower, reproduce the physical and material characteristics that created the proven bed. If you intentionally change size, geometry or ceramic specification, treat the project as an engineering retrofit rather than a simple replacement purchase.