Trenchless Technology

JAN 2019

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A H O U S TO N R E F I N E RY recently required rehabilitation of 16,000 ft of 6-in. ductile iron pipe as it was experiencing multiple leaks at the pipe's joints and pinholes. This refinery — also a tank terminal — is one of the most sophisticated chemical tank terminals in the world, and the hub for global and regional trades to and from the U.S. Gulf. This particular terminal operates a 6-in. processed water line that carries treated wastewater to a treatment facility lo - cated about three miles north of the refinery. This 35-year- old line experienced multiple failures and leaks that forced the terminal to suspend use of the processed water line. The owners of the terminal were forced to truck the material down to the treatment plant at an exorbitant cost . Facility engineers sent out an RFP for cured-in-place pipe (CIPP) in order to rehabilitate the line. Complicating the process was the fact that the line went underneath railways, waterways and went through a corridor, which has a net- work of pipelines through it making conventional dig-and- replace impractical . A Primus Line certified installer responded to the RFP and met with the client to discuss potential solutions. The client quickly recognized that CIPP was not the best solu- tion, and that Primus line was the correct choice as a reha- bilitation method. Primus Line's solution was one third of the cost and one third of the project duration time, com- pared to that of conventional CIPP methods. It is important to understand how this product is different than CIPP or conventional sliplining . Typical length for CIPP is about 1,000 lf maximum. While some of the larger installers have equipment that is capable of longer runs, the average run proposed by the CIPP contractors to the owner was average of 750 lf; whereas the Primus Line is capable of 8,200 lf in one run. This Flexible Kevlar liner, which is a composite system consisting of the liner itself and the end fitting or connec- tors, this system was originally designed for the gas market and is incredibly durable and capable of high pressure as a result of the combination of Kevlar sandwiched between polyethylene outer and inner sleeve providing protection of Kevlar weave from any damage during the insertion process. The inner coating of polyethylene produces a factor of 150 and increases the volume of water moving through the pipe. The liner is stored on spools, pre-folded and taped ready to be pulled into place, this reduces the friction during the in- sertions and allows us to navigate multiple changes in di- rection and inclination. Once the liner has been pulled into place, crews utilize air pressure at roughly 7 lbs to inflate the liner and break the tape. It 's at this point the pipe takes on the round shape it will maintain the rest of its service life. The connectors are then installed providing a mono - lithic and guaranteed leak-free pipe for years of trouble-free service. This process truly mitigates all risk of a problem during the installation. The installation process is generally 30 T R E N C H L E S S T EC H N O LO GY JA N UA RY 2019 By John Moody Houston Refinery Benefits from Trenchless Relining to Rehab Processed Water Line

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