Complete Process Column RFQ: Shell, Tower Internals and Engineering Interfaces
Technical Guide | Process Equipment Procurement | KEMVORI Petrochemical Equipment Limited
Direct Engineering Answer: What Should a Complete Process Column RFQ Include?
A complete process column RFQ must clearly define the process requirements, vessel mechanical scope, tower internals, engineering calculations, interfaces, inspection and documentation.
A complete column package may include:
Pressure vessel shell.
Trays or structured packing.
Liquid distributors.
Liquid collectors.
Packing supports.
Mist eliminators.
Nozzles and connections.
Internal support arrangements.
Engineering drawings.
Inspection and testing.
However, supplying a complete column does not automatically mean that every engineering and certification responsibility is included.
The purchaser must define the battery limits and establish who is responsible for each part of the project.
1. Separate the Vessel Shell From Tower Internals
The vessel pressure boundary and internal separation equipment have different design responsibilities.
Vessel Mechanical Scope
May include:
Shell and head dimensions.
Design pressure.
Design temperature.
Corrosion allowance.
Material specification.
Nozzle arrangement.
Pressure-boundary calculations.
Applicable vessel construction code.
Required certification.
Tower Internals Scope
May include:
Tray systems.
Structured packing.
Random packing.
Liquid distributors.
Collectors.
Packing supports.
Hold-down grids.
Mist eliminators.
Internal attachments.
The RFQ should explicitly state whether these scopes are supplied together or separately.
2. Define the Process Design Basis
A complete process column quotation requires a clear process basis.
Provide:
Process description.
Gas and liquid compositions.
Minimum flow.
Normal flow.
Maximum flow.
Operating pressure.
Operating temperature.
Physical properties.
Required separation duty.
Product specifications.
Turndown requirements.
Where multiple operating cases exist, identify the governing design cases.
A single nominal flow rate may not be sufficient for final hydraulic evaluation.
3. Define Hydraulic Calculation Responsibilities
Tower internals selection should be supported by appropriate hydraulic calculations.
The RFQ should identify whether the supplier is responsible for:
Vapor-liquid loading calculations.
Tray capacity assessment.
Packing selection.
Flooding evaluation.
Pressure-drop calculations.
Liquid distribution review.
Distributor sizing.
Equipment performance evaluation.
The calculation deliverables should identify the process data, operating cases, assumptions and equipment geometry used.
KEMVORI supports project-based hydraulic calculations for tower internals according to the available process data and agreed engineering scope.
Hydraulic internals calculations should not be confused with the mechanical design or certification of the pressure vessel.
4. Define Mechanical and Engineering Interfaces
Interface coordination is essential when the vessel and internals are supplied by different companies.
Clarify:
Column inside diameter.
Support ring elevations.
Internal support loads.
Nozzle positions.
Feed inlet arrangements.
Manway dimensions.
Internal clearances.
Installation access.
Attachment responsibilities.
An interface drawing should identify the governing dimensions and responsible design parties.
5. Establish Applicable Codes and Certification Requirements
The RFQ should identify the required vessel construction code and applicable project standards.
Confirm:
Governing design code.
Required design calculations.
Material certificates.
Welding requirements.
Inspection and testing.
Third-party inspection.
Pressure testing.
Documentation.
Certification responsibilities.
Do not assume that a supplier holds a particular certification or that a particular pressure-vessel approval is included.
These requirements must be verified and agreed for the actual project.
6. Prepare a Clear Technical and Commercial Scope
A complete RFQ should distinguish between:
Engineering: Process review, hydraulic calculations and detailed drawings.
Manufacturing: Vessel fabrication and internal component fabrication.
Quality Assurance: Inspection, testing and material documentation.
Installation: Site assembly, supervision and commissioning where required.
Commercial Delivery: Packaging, shipping, destination and delivery terms.
A supplier should be able to identify included work, exclusions and technical assumptions.
7. Common Complete Column RFQ Mistakes
Mistake 1: Providing only vessel dimensions.
Solution: Supply process data and separation requirements.
Mistake 2: Assuming hydraulic calculations are automatically included.
Solution: Define the required calculations and deliverables.
Mistake 3: Ignoring the vessel-internals interface.
Solution: Provide nozzle, support and installation drawings.
Mistake 4: Failing to specify applicable vessel standards.
Solution: Identify code and certification requirements.
Mistake 5: Comparing quotations with different scopes.
Solution: Use a common technical and commercial RFQ basis.
Mistake 6: Leaving installation responsibilities undefined.
Solution: Establish supply and site-work boundaries before award.
8. Complete Process Column RFQ Checklist
Provide:
Process datasheet.
PFD and P&ID.
Vessel GA.
Design pressure and temperature.
Shell material requirements.
Applicable construction code.
Column internals layout.
Hydraulic calculation requirements.
Nozzle and support details.
Material specifications.
Inspection and testing requirements.
Certification requirements.
Documentation list.
Delivery destination.
Installation and commissioning scope.
Frequently Asked Questions
Does a complete column quotation automatically include hydraulic calculations?
No. The calculation scope must be stated in the quotation and technical agreement.
Is pressure-vessel certification automatically included?
No. Applicable codes and required certification must be confirmed for the project.
Can the vessel shell and tower internals be supplied separately?
Yes. Separate supply is possible when mechanical and engineering interfaces are properly coordinated.
Why are battery limits important?
They establish exactly which equipment, services and engineering responsibilities are included.
Can KEMVORI support tower internals within a complete column project?
KEMVORI supports tower internals engineering, hydraulic calculations, customized fabrication and interface coordination according to the agreed project scope.
Engineering Support from KEMVORI
KEMVORI Petrochemical Equipment Limited provides tower internals and engineering solutions for distillation, absorption, refining and petrochemical projects.
Our project support can include:
Tray and packing selection.
Liquid distributor design.
Collector and support systems.
Hydraulic calculations.
Pressure-drop evaluation.
Flooding assessment.
Engineering interface coordination.
Customized manufacturing.
Send your process datasheet, column GA and RFQ scope for a technical review.
Engineering Design & Hydraulic Calculations
Related Guide: Interface Coordination Between Vessel Fabricator and Tower Internals Supplier
Related Guide: How EPC Buyers Compare Tower Internals Technical Bids
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