Transmission Pipeline Maintenance

Hydride Compressors using reversible metal hydride alloys offer an economical alternative to traditional mechanical compressors for GH2. The simplicity and passive operation of the hydride compression process offers many advantages over mechanical compressors. Hydride compressors are compact, silent, do not have dynamic seals, require very little maintenance, and can operate unattended for long periods. However, they are a very new and may be difficult to be built at the scale required for GH2 transmission pipeline service. 

A second important point is that the maintenance and inspection strategy should differ between distribution and transmission systems to reflect the much higher failure consequences for transmission pipelines compared to those of a typical distribution line. Approaches that may not be economically viable for a distribution system could be employed advantageously in a transmission system to prevent failures. Essentially, the low consequences associated with a single distribution failure also mean that the emphasis in distribution systems should be on failure management in order to minimize life-cycle costs while a more proactive failure prevention approach would be better suited for transmission systems due to the high consequences of associated failures [6]. 

Figure 12.10 illustrates how a major gas transmission pipeline company adopted FTA for the risk assessment of SCC corrosion on its 18,000-km gas pipeline network [13 14j. The rupture risk FTA was normally performed for the review and analytical examination of systems or equipment to emphasize the lower-level fault occurrences. These results also served to schedule maintenance operations, conduct surveys, and plan research and development efforts. 

A gas-gathering and transmission system consists of sources of gas, arcs composed of pipeline segments, compressor stations, and delivery sites. The design or expansion of a gas pipeline transmission system involves capital expenditures as well as the continuing cost of operation and maintenance. Many factors have to be considered, including... 

Distribution pipelines are mostly in populated areas and transmission lines may cross through or near multiple populated areas intermittently with sparsely populated areas as they carry the product long distances. Pipelines lie within a right-of-way land corridor, usually leased from the landowners. The right-of-way provides access for ongoing maintenance and future expansion of the systems. 

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