PIPE NETWORKS

Factors that are important for the limitation of protected areas are the pipe network structure, degree of mesh, number of service pipes, type of pipe connections, quality of the pipe coating and availability of protection current as well as stray current effects. A protected area in a distribution network is shown in Fig. 10-11 with separate parts of the network (NT I to NT IV). Previous experience has shown that protected areas of 1 to 2 km with lengths of pipeline from 10 to 20 km are advantageous [30],... 

A higher content of AI2O3 and SiOj is critical for the composition of the protective films in the tubing, assuming the water contains silicates or silicic acid. The protective films have a maximum thickness of 1.5 mm and cannot grow further. The corrosion process can be stopped even in copper pipe networks with type I pitting [21] by providing a reaction tank with impressed current aluminum anodes. 

There are many reasons for significant investment in FCC power trains and, thus, power train maintenance. These power recovery machines handle catalyst-laden gas at high temperature. Because the recovery system is connected to the processing plant, the steam pipe network and the electrical power grid, a power train upset is likely to rapidly extend from the FCC unit to the entire plant. 

For a saturated (bubble point) liquid, pipe vertically downward from the drawoff nozzle as close to the nozzle as possible. This gives maximum static head above any horizontal sections or piping networks ahead of the pump. 

Safety relief systems are verified as part of PSM. This includes the PS Vs themselves and also flare system piping networks. Safety relief valves are covered in Section I—Fluid Flow. A good procedure for sizing the flare system piping is found in Section 19—Safety-Relief Manifolds. This method, first published in the Oil and Gas Journal, has been adopted by APl. I have also used... 

In March 1877, New York inventor Birdshill I lolly introduced the Holly Steam Combination System to provide heat and power using steam distributed through an underground piping network. The first... 

Construct the reduced pipe network corresponding to the topological graph of the worst-case state. 

Remove all unsatisfactory pipes from the reduced pipe network. Go to stage 1, step 2. 

For a geonet LDCR system, the flow rate for the geonet is determined in the laboratory by using the ASTM D4716 test method, and the value is modified to meet site-specific situations. The geonet flow rate DR is then determined in the same way as for the granular system. No pipe network is needed. 

Computational performance data on the Galerkin method were reported by Rachford and Dupont (Rl). Time increments of the order of 5 minutes are typical. According to these authors an average of 120 pipe steps per CPU second on a CDC 6600 computer was achieved. Approximately 100 words of storage per pipe were required for array storage and 12,000 words of storage for the program and subroutines. On that basis the authors estimated that a 1000-pipe network can be simulated on a full-size CDC 6600 computer at about 100 CPU seconds per simulated hour. 

For pipe networks the pressure will increase in front of the flame front as the flame travels through the network. The downstream pressure may be 8 to 16 times greater than the original upstream pressure. This concept is called pressure piling. With pressure piling, therefore, p2 = Pi X 8 X 8 and p2 = P X 16 X 16 for Equations 12-1 and 12-2, respectively. 

When a pipe network is involved, the downstream pi increases because of pressure piling therefore p2 may increase by as much as another factor of 20. 

Detonation failures in pipe networks are always downstream from the ignition source. They usually occur at pipe elbows or other pipe constrictions, such as valves. Blast pressures can shatter an elbow into many small fragments. A detonation in light-gauge ductwork can tear the duct along seams and can also produce a large amount of structural distortion in the torn ducts. 

Design systems for easy operation and easy maintenance for example, install manual valves within easy reach of the operators, and design pipe networks for easy maintenance or with easy access to equipment requiring maintenance. 

A A Heiba C Dean, "ERS Design and Rating with INPLANT - A Pipe Network Flow Simulator", Attachment 11, Minutes of 16th DIERS Users Group Meeting, Boston, September 1994... 

In some other instances, engineers have counted flanges on long and complicated piping networks to help estimate potential leak sources. Their time would have been better spent getting an estimate on the maintenance mind-set so as to determine what programs were in progress to reduce leaks by the ever-present threats of external corrosion. 

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