NGL/LPG Plant Retrofit Design Checklist

Ortloff Engineers can complete a first pass analysis on a retrofit design if we have the information required in the New Plant Design Checklist plus an original process flow diagram and material balance.

A more thorough retrofit design will require as much of the following additional information as possible:

• Heat exchanger supplier data sheets with tube bundle and baffle detail drawings for shell and tube exchangers and layer and fin details for plate-fin exchangers.
• Expander data sheets and supplier's performance data.
• Up-to-date PFDs (with material balance) and P&IDs.
• Performance curves for all centrifugal compressors and pumps.
• Cylinder and driver data for all reciprocating compressors.
• Sizes and data sheets for all separators and columns.
• Demethanizer/deethanizer column drawings.
• Demethanizer/deethanizer internals drawings.
• Piping isometric sketches for side heater and reboiler piping.
• Up-to-date plot plan.
• Supplemental information on compressor or gas turbine upgrades which owner may have already considered.
• Information on known performance problems which should be addressed in the retrofit design such as poor expander performance, fouling of heat exchangers, column flooding, excessive pressure drops, control problems.
• Dehydration system sieve type, weight per vessel, vessel and bed dimensions, number of vessels, method of regeneration, regen gas heater design duty.
• Fractionation system equipment data, especially if deethanizer is operated with the demethanizer in an ethane recovery mode and they share a common refrigeration system.

Ideally, we prefer to borrow a complete set of engineering data books for use during the final design of the retrofit. The data books typically contain all the information needed to properly re-rate the existing equipment.

A retrofit design can be much more time consuming than a new plant design. This is because the performance of all the existing equipment including the compressors and exchangers must be accommodated in the retrofit design.

Process performance guarantees are available for both new plant and retrofit designs. Ortloff can also work with your chosen contractor during the detailed design stage of the project to make sure that the final design will perform as expected.