Gas Distributor RFQs: Which Vessel and Process Data Must Be Frozen Before Fabrication?

Gas distributors can be highly dependent on the actual vessel layout.

For this reason, early budget quotations may be based on process duty alone, while final fabrication requires accurate mechanical interface information.

Procurement should know when that transition occurs.

Gas Flow Conditions

The supplier needs:

normal and maximum gas rate.

Pressure and temperature should also be provided so the operating volume and density basis are clear.

Gas Composition

For material selection and certain design considerations, gas composition can be relevant.

If corrosive components are present, they should be identified.

Inlet Nozzle

The RFQ should provide:

diameter, centerline elevation, orientation, and internal projection where relevant.

The supplier should not fabricate against an assumed inlet location.

Tower Inside Diameter

Actual shell dimensions are needed to finalize the distributor envelope and clearances.

Available Space

The supplier should know:

distance from inlet to support grid, packing, bottom head, and nearby internals.

This establishes the available mixing and installation space.

Support Interface

Existing:

rings, beams, brackets, or clips

should appear on the vessel drawing.

If new supports are part of supplier scope, that should also be stated.

Pressure Drop

If the project has an allowable distributor pressure-drop limit, it should be provided.

Flow Uniformity Requirement

Where the process designer has specified a particular distribution criterion, include it in the RFQ.

Otherwise, the supplier should state the basis of its design.

Manway Access

The distributor may need to be supplied in sections.

Actual access limitations should be available before fabrication.

Engineering Takeaway

A gas distributor becomes fabrication-ready only after both process duty and vessel interfaces are frozen.

The inlet nozzle, available space, supports, pressure-drop requirement, tower geometry, and installation access are as important as the gas rate itself.