Propane Equivalent for Flexible Plant Design

Presented at Annual Conference, 13 - 15 September 2017 at Sofitel Chain Bridge Hotel, Budapest by
Fiona George, WorleyParsons
The Question: How to design and operate a gas processing plant which will be flexible enough to handle a wide range of feed gas compositions and rates.
The Solution: Propane Equivalent - A single equation to define feed gas composition.
The feed to a gas processing plant generally comprises of gas from several different fields. Over time the composition and rates of these individual fields will vary. If there are several fields feeding one plant then there are numerous possible permutations for the composition and rate of the feed to the plant.
The difference in feed compositions and how this impacts the processing of the gas are not easy to evaluate. Small differences in feed composition can have a significant impact on the ability of the gas plant to process the gas to meet the required specifications. Hydrocarbon equivalence factors have proved to be successful in assessing the sales gas interchangeability in the UK North Sea for many years. It was therefore logical to assess if this method of calculating gas equivalence could be modified and applied to feed compositions to gas processing plants.
This paper discusses why the Propane Equivalent equation was developed and how it can be applied to the design of a new gas processing plant and for debottlenecking of existing plant. It enables an assessment of how differences in feed compositions will impact the processing of the gas and how these differences can be accommodated.