The Development of a Probe for Detection of PCBs and Other Liquids in Live Gas Mains

摘要

The presence of water in lower pressure gas mains, arising from groundwater leakage or changes in the process quality can lead to serious network integrity issues, principally sources of corrosion and pipeline failure. Other issues involve gas pressure reduction, total blockage as well as a reduced energy content (calorific) that may adversely affect the consumer's utilization. Conventional camera based visualization techniques have the principal disadvantage of failing to detect very thin films of water ingress as well as being unable to discriminate water from other liquids used for leakage reduction and joint sealants. Advantica (formerly BG Technology) have successfully developed and field trialed a novel optical probe used to detect the merest trace of water in distribution mains. The probe is designed for live pressure insertion and can be rodded significant lengths without disruption of supply. The spectrophotometric methods used by the probe's software discriminate uniquely and quantifiably for the presence of water. Sub micro-liter quantities of water can be pinpointed objectively and rapidly thereby leading to significant cost savings in the cost and scale of pipe repair and corrosion mitigation. Results from an end user's gas utility operation will be presented. Novel work co funded by Advantica has established proof of concept that the probe technology can be utilized to discriminate for the in-pipe presence of Poly Chlorinated Bi-phenyls (PCBs). Once fully commercialized such a solid state probe will enable utility field crews to safely and efficiently monitor for the presence of PCB contamination without the direct need for complex chemical and laboratory tests. Key findings from the developmental work to date will be discussed.