Page 183 - Pipeline Pigging Technology

Pipeline Pigging Technology

BACKGROUND

The St.Charles Project for Missouri Pipeline Co involved converting the
existing 12-in (loop) pipeline to natural gas service. The original pipeline was
commissioned for transporting crude oil in 1948 and 1961, and had been
abandoned since 1982. Upon abandonment, the pipeline was displaced of
crude oil and purged with nitrogen. Therefore, the line was expected to be
in relatively good condition.
The 12-in loop line runs from Panhandle Eastern's pipeline (PEPL) in Pike
County, Missouri (near Curryville, MO), to Woodriver, IL, approximately 85
miles SE. Various sections and branches of iiew pipeline were included in the
plans to complete the loop line, including an 11.6-mile section of 16-in
pipeline between the Auburn and Chantilly stations, and 3.8 miles of new
pipeline between Curryville and the PEPL tie-in (see Fig.l).
In October, 1989, DS was contacted by Missouri Pipeline Co for recom-
mendations to clean the existing pipeline for conversion to natural gas
service. The pipeline would be cleaned, hydrotested, dewatered, dried and
placed in service. The primary objectives set forth for DS were to:

1. Remove residual crude oil from the pipeline.
2. Remove loose or adhering debris which might cause operational
problems in the pipeline.
3. Ultimately, clean the pipeline, such that the hydrotest water would
meet EPA standards for discharge (i.e. less than or equal to: lOOppm
suspended particles, and 20ppm oil and grease).
4. Provide a contingency plan to comply with the parameters in (3), in
the event that the criteria were not originally satisfied.

The gellypig service was originally proposed as a single pig train, launched
at W.Alton, MO, to Curryville, MO. This service would involve exchanging 12-
in and 16-in mechanical pigs at the Auburn and Chantilly stations, as the pig
train enters and leaves the 11.6 mile section of new 16-in pipeline.
An alternative approach was proposed and selected by Missouri Pipeline,
such that the operation would be completed in two distinct phases (two
gellypig trains), as follows:

Phase 1 - from WAlton to Chantilly Station (approximately 41.5 miles
of 12-in pipeline)
Phase 2 - from Auburn Station to Curryville Junction (approximately
24.6 miles of 12-in pipeline)

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