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Project Award

April 1960

Project Completion

November 1960

Willbros provided engineering services, ROW acquisition,material procurement, and construction for the Mid-America Pipelinethe first major common-carrier system

devoted exclusively to LPG. The 3,540-km (2,200-mile) ANSI 900system of 4-, 6-, 8-, and 10-inch pipeline was constructed in the early1960s. The system included six delivery terminals, two operatingterminals with washed cavern storage, aboveground storage, 14 pumpstations, and communication systems.

The Mid-America Pipeline extends from the Permian basin in New

Mexico to Conway, Kansas, where it branches to Pine Bend,Minnesota (near Minneapolis), and to Janesville, Wisconsin. Thesystem was developed to meet the increased demand for propane inthe upper midwest, and its most important advantage is thecontinuous supply of products.

When LPG is one of the products handled by a pipeline, large-volume, low-cost pressure storage at critical points is essential. Thistype of storage can be provided for the least cost in caverns dissolvedout of naturally occurring salt deposits. Mid-America uses suchstorage at Hobbs terminal where the gathering system ends and the

Worlds First Major LPG Pipeline SystemMid-America Pipeline Company

United States

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MINNESOTA

IOWA

NEBRASKA

KANSAS

OKLAHOMA

TEXAS

NEWMEXICO

MISSOURI

ILLINOIS

WISCONSIN

Sanborn

Iowa City

Conway

WellsfordMcPherson

Eskridge

KearneyLinn

Pine Bend

Moberly

Greenwood

Hobbs

Beaver

Pampa

Tulia

Levelland

Janesville

LPG Pipeline

Terminal Stations

Pump Stations

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mainline begins and at the McPherson terminal where the mainlinebranches and ties into other facilities. Approximately 150 Mbbl ofstorage is desirable at each location.

Aqua-type underground storage is also utilized, consisting of acavern that is completely full of liquid and under pressure at all times.Water fills any void not occupied by product. Three undergroundcaverns of 27-Mbbl each were developed and tied into a centrallylocated manifold. The manifold makes it possible to operate thecaverns in much the same way as an aboveground tankage. Productdewatering facilities included water knockout and thermalregenerative activated aluminum dehydration to -40F dewpoint. A150-hp water-injection pump is used for product recovery. Differentproducts can be stored in each cavern and can be recoveredsimultaneously. Water-metering facilities can continuously enlargeexisting storage and develop additional caverns.

Six 1.5-Mbbl aboveground tanks are used for propane service. Theyare ASME code stamped for 250 psi working pressure, 100% x-rayed,

and fully stress-relieved. Suction and fill valves are motor operated. Atop equalizer system connects the vapor space of all tanks, allowingfree breathing of different temperatures between tankstherebyincreasing filling and emptying rates. Two four-port safety relief valvemanifolds protect each tank.

Seven distribution terminals are included in the system. Facilitiesincluded aboveground receiving storage and truck and rail loadingsystems for distribution. Odorant injection was provided for all truckand rail loading systems. A general design and layout was selected tosimplify operations and maintenance, and was modified only to satisfylocal conditions.