Selected work/Gas pipeline concept
A concept and pre-FEED study that compared candidate diameters across the full pressure envelope before fixing the line size, and set out the FEED deliverables with the data each needs.
Outcome
Objective met4 of 4 success criteria. Read the conclusionA developer needed a pipeline from a gas source to a consumer and had a nominal flow rate in mind. The diameter could not be chosen from the flow rate alone. The minimum source pressure, the required delivery pressure, the demand variation and the future capacity each changed the practical line size or showed that compression would be needed.
We ran the hydraulics for the candidate diameters across the pressure cases: low and high source pressure, minimum delivery pressure at the consumer, present and future demand. Gas velocity was checked against the erosion limit in each case. We set out the interfaces for metering, safeguarding, pigging and corrosion control, and the equipment required at each end of the line. Concept drawings were issued as conceptual, not for construction. A deliverable register listed each FEED document with the data it needs and the check that closes it.
The operating envelope sets the line size
Delivery pressure against flow for three candidate diameters, bounded by the source pressure range, the minimum delivery pressure and the velocity limit.
Conceptual, not for constructionThe diameter stayed conditional on the confirmed pressure envelope rather than being fixed early. The developer could see which pressure outcome would change the answer and what data FEED would need first.
The objective was a line size the developer could take into FEED with its conditions and its data needs stated. It was achieved. Every candidate diameter was tested on the same pressure and demand cases, the selected case was issued as conditional on the confirmed source pressure range, and the deliverable register was accepted as the basis for the FEED scope.
| Success criterion | Met | How it was achieved |
|---|---|---|
| iEvery candidate diameter tested against the same pressure and demand cases | Met | Hydraulic comparison issued for all cases with velocity and pressure drop tabulated |
| iiThe selected case stated with the condition that makes it valid | Met | Selected case issued as conditional on the confirmed source pressure range |
| iiiDrawings marked conceptual, not for construction | Met | Concept schemes issued at Revision C with the conceptual marking on every sheet |
| ivFEED data list issued with an owner and a check for each item | Met | Deliverable register accepted by the developer as the basis for the FEED scope |
Deliverables
Evidence note
Concept and pre-FEED material prepared by Assos Tech, Revision C. Not an issued-for-construction design and not a claim that the pipeline has been built. Client, route, rates, dimensions and budget not shown.
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