Pipeline maintenance requirements

Maintenance requirements should be the same for an emulsion pipeline as for a conventional petroleum pipeline. Similarly, no unusual maintenance is expected for the emulsion preparation or demulsification parts of the system. 

Issues such as achieving the required purity of the C02, transfer of custody, pipeline maintenance, and safety are well understood, and thus land-based transport of C02 must be considered as a mature technology. An individual C02 pipeline that is safe, reliable, and economical can be constructed with assurance (Fig. 6-5). 

This is another vital part of an impressed current system. The T/R must be rugged and reliable with minimal maintenance requirements. It should be easy to maintain with good instruction manuals, circuit diagrams for maintenance and easy access to fuses and other consumable and replaceable components. Compared with pipeline or marine CP applications (steel piles, etc.) the power demand is modest. Most steel in concrete needs less than 10 mA-m to provide protection, usually at less than 10 V. The power for a 100 watt light bulb will protect 10,000 m. This means that a single phase, air cooled T/R will usually protect even the largest structure and power consumption is rarely an economic concern. 

Safety critical valves are subject to extensive inspection and maintenance requirements. Every pipeline riser connected to the platform must have an EDSV with a local closure control panel that ensures the ESDV remains closed once it has been tripped by an... 

Most pipeline samples require some filtering. Since all filter elements eventually plug, they should be replaced on a regular maintenance schedule. There are several types of filter designs. 

Filtration and water-knockout systems are used to clean up the gas before it enters a compressor. Cooling systems are sometimes required to maintain compressor discharge temperatures below 54°C to avoid damage to the pipeline s protective coatings. Automated compressor stations are typically staffed by maintenance and repair personnel eight hours per day, five days per week. Other stations are staffed on a 24-hour basis because personnel must start, stop, and regulate compressors in response to orders from the dispatch office. 

A reactor was prepared for maintenance and washed out. No welding needed to be done, and no entry was required, so it was decided not to slip-plate off the reactor but to rely on valve isolations. Some flammable vapor leaked through the closed valves into the reactor and was ignited by a high-speed abrasive wheel, which was being used to cut through one of the pipelines attached to the vessel. The reactor head was blown off and killed two men. It was estimated that 7 kg of hydrocarbon vapor could have caused the explosion. 

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. 

The owner shall have overall responsibility for compliance with this Code and for establishing the requirements for design, construction, examination, inspection, testing, operation, and maintenance of the hydrogen piping or pipeline system. 

As a means of maintaining the integrity of its pipeline system, each operating company shall establish and implement procedures for continuing surveillance of its facilities. Studies shall be initiated and action shall be taken where unusual operating and maintenance conditions occur, such as failures, leakage history, drop in flow efficiency due to internal corrosion, or substantial changes in cathodic protection requirements. 

This Part sets forth requirements for materials, components, design, fabrication, assembly, erection, inspection, examination, testing, operation, and maintenance of hydrogen pipelines. 

But, all of these obvious technical pipeline considerations are sometimes overh>oked, and many of the most infamous incidents have involved poor practices in piping design, in operations, or in piping maintenance systems. The American Insurance Association states Piping hazards are often underrated as compared to pressure vessels although the history of failures does not warrant this... . Piping systems should be located in. serviceable areas. They should be constructed in accordance with appropriate code requirements and inspected by appropriate means.. .. [20]... 

In the regulations, factors are addressed by specific requirements. As an example, some of the requirements for the operation and maintenance of natural gas pipelines under 49 CFR 192 Subparts L and M are shown in Table 2. 

As shown in Fig. 15.6, external DC current is supplied from a power source such as a rectifier. The external DC current is used to cathodicaUy polarize the pipeHne. Impressed Current System (ICS) can be used to protect bare and poorly coated pipeHnes because of high current capacity. The anodes are made of durable materials that resist wear or dissolution. Iron with 14% silicon, carbon, and graphite are some commonly used anodes for pipeline protection [17,18]. All impressed current CPs require routine maintenance because they involve a power supply and more electrical connections than sacrificial systems. 

Successful application of cathodic protection depends upon the selection, design, installation, and maintenance of the system. Before designing the cathodic protection systems, adequate field data must be collected, analyzed, and evaluated. Nature and conditions of the soil are reflected by field measurements like soil resistance, hydrogen ion activity (pH), and the redox potential. To understand the nature of the pipeline, potential measurements, coating resistance, and meaningful design current requirement tests must be conducted. 

It is essential to make an important decision on the selection of the CP system to be instaUed. The choice of the CP system is based on the environment in which the pipeline is operated. The merits of each system are iUustrated in Section 15.2.3. Sacrificial protection is generaUy employed in environments with low soil resistance (10,000 Q cm) with a relatively low protective current requirement because of the low driving voltage. WeU-coated and isolated pipeUnes favor the instaUation of a sacrificial system in high resistive soils. On the other hand, ICS are usuaUy instaUed in conditions where the current requirements are higher and for pipelines that are bare or poorly coated. In aU cases, the final decision is based on the total instaUation and annual maintenance cost of the systems. 

It was the only accident the cause of which is concerned with LBC using. As a result of low studying physical and chemical coolant operation processes, the substantiated specifications on impurity compositions in coolant, instrumentation for coolant quality control and equipment to provide the maintenance of required coolant qualities in the course of operation have been lacked. This level of LBC knowledge can be compared with that of water coolant when it was allowed to convey water from the water pipeline into the steam boiler. 

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