A major conversion project was undertaken in 2001 to convert a fifty-year-old natural gas transmission pipeline to refined petroleum products service. A joint venture Limited Liability Corporation (LLC) was formed to modify and convert the existing pipeline, as well as operate and maintain the system to transport refined liquid fuels from the Gulf Coast to the Midwestern United States.
This paper will outline the methods employed to detect and remove potentially hazardous defects prior to startup. It will discuss the metallurgical evaluation of the 1950?s vintage pipe and known integrity concerns. It will discuss the use and objectives of In Line Inspection technology, and how this technology combined with a customized hydrostatic testing protocol produced a comprehensive evaluation of the system. It will discuss the USDOT(2) Office of Pipeline Safety?s (OPS) recently enacted Integrity Management Plan rule and how this rule affected the planning and execution of the project.
Finally this paper will describe the extensive amount of planning, coordination, and communication required to execute the integrity assessment of approximately 700 miles (1126 km) of fifty year old pipeline which today serves the motor fuel deficient Midwest region.
Fifty years ago, the Trunkline Gas Company(3) (TGC) 100-1 Pipe Line was designed and constructed in order to provide an efficient means of carrying natural gas from the supply rich areas of South Texas and the Gulf Coast, to the rapidly growing and industrially active Midwest. In the past fifty years, many things have changed. From the expansion of existing pipeline systems to the in flux of natural gas supply from Canada, the Midwest has seen its natural gas supply options increase dramatically. Consequently there is less Midwest demand for natural gas; however, the demand for other petroleum products has increased.
The supply of refined petroleum products is extremely limited in many parts of the United States, and just as natural gas was in high demand in the Midwest fifty years ago, today there is high Midwest demand for refined petroleum products. So as demand for natural gas has waned while demand for refined products has increased, it makes sense to re-evaluate and if possible reassemble the pipeline infrastructure to better serve the balance between supply and demand.
The country?s most abundant supply of refined petroleum products exists within the Gulf Coast region. The major obstacle between transporting these products to high demand areas such as the Midwest is that new pipeline construction costs have increased dramatically over the past fifty years, preventing the construction of new pipeline systems. It was quickly recognized that the conversion of an existing pipeline, such as the TGC 100-1 Line, could provide an economically viable option for developing a system to transport refined petroleum products from the Gulf Coast to the Midwest.
The Centennial Pipeline Project is an example of reassembling existing pipeline infrastructure in order to meet today?s industry demands. The project involves the conversion of approximately 700 miles (1126 km) of large diameter pipeline from natural gas to refined petroleum products service, coupled with the new construction of additional pipeline and pipeline facilities.
The pipeline project is a joint venture between CMS Energy(4), Marathon Ashland Pipe Line LLC(5) (pipeline system operator) and TEPPCO(6). The project involves the new construction of a 24 pipeline from Beaumont, TX to Longville, LA (~75 miles, 121 km) and the conversion of a 1951 vintage 26 natural gas pipeline that runs from Longville, LA to Deiterich, IL (674 miles, 1084 km). Five newly
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