Cast iron, pipeline

Comply with requirements of insurance companies regarding fire fighting facilities to be provided on the premises, e.g. cast iron pipelines, dedicated water pumps of special design for fire fighting, separate power supply feeders/DG set, CO2 cylinders, sand buckets, dry chemical powder-type fire extinguishers, long hose reels smoke detectors, and sprinklers must be installed and maintained. 

Fig. 2. Relationship between generalized Reynolds number Re and friction coefficient X, cast iron pipeline 250 mm, ...

Cast iron pipelines have in some cases lasted for decades transporting seawater or salt solutions [91, 92]. 

Table 3 Ductile cast-iron pipeline system for the transportation of waste water in drinking-water protection zones II [23]...

Note also that graphitic corrosion may occur preferentially in poorly accessible areas, such as the bottom of pipelines. Trouble-free service of cast iron components does not necessarily indicate that all is well, since components suffering severe graphitic corrosion may continue to operate until an inadvertent or intentional (e.g., pressuretesting) shock load is applied. At this point massive, catastrophic failures can occur. 

With the fall of the Roman Empire, the ancient water supplies petered out. In early medieval times, people were content to conduct local water in wooden pipes to public cisterns. The first wooden pipelines for water were laid at Liibeck about 1293 and in 1365 at Nuremberg. In 1412 the Augsburg master builder Leopold Karg first used wrought-iron pipes in conjunction with wooden pipes to supply water. Because of their propensity to corrosion, they seem to have proved a failure and a few years later they were exchanged for wooden, lead, and cast-iron pipes. 

The first anode installation for the cathodic protection of gas pipelines in New Orleans consisted of a 5-m-long horizontal cast-iron tube. Later old tramway lines were used. Since in downtown New Orleans there was no suitable place to install impressed current anodes and to avoid detrimental effects on other pipelines, Kuhn recommended the use of deep anodes which were first installed in 1952 at a depth... 

Local corrosion or pitting is more important for practical purposes than the rate of general corrosion, and may proceed 10 times or so more rapidly than this. Inasmuch as certain types of cast iron are liable to suffer graphitic corrosion, whereas steel does not, steel might theoretically be expected to show to some advantage when used for buried pipelines. In practice, however, a cast-iron pipe has to be of stouter wall than a steel pipe for equal strength, and it is doubtful whether any distinction between the rust resistance of the two materials in the soil is justified. 

In pipelining, the trend is towards all-welded steel for long lines, and since the wall thickness is less than that of cast iron, protection is the more important. Many types of coating are used, from thick concrete to thin paint films, and each has its own particular suitability, but the majority of pipelines throughout the world today are coated with hot-applied coal tar or petroleum asphalt-base-filled pipeline enamels, into which reinforcing wraps, such as glass fibre are applied. 

Graphitic corrosion has been observed on buried pipelines after many years of service. Gray cast iron has a continuous graphite network in its microstructure that is cathodic to iron and remains behind as a weak, porous network as the iron is selectively removed... 

The pure acid is delivered by air pressure from the MCA receiver, through silver pipelines to a plastic-coated, tile-lined, steam-jacketed vessel, from which it flows to a totally enclosed cast-iron drum flaker. The feed tank and flaker are both vented to a chimney through a baffle box. 

Impressed current anodes must be corrosion resistant and otherwise durable in the environment in which they are used. They must have low consumption rates when coimected to a CP source. All materials used for impressed current anodes are cathodic (more noble) than steel. High silicon cast iron (Fe-0.95C-0.75Mn-14.5Si-4.5Cr) is used for onshore CP applications and in other locations where abrasion resistance and other mechanical damage considerations are important [1]. Graphite anodes are extensively used for onshore pipeline CP applications in which they can be buried in multiple-anode ground beds. However, graphite must be stored and handled carefully because of its brittle nature. 

Gas Distribution The nation s natural gas distfibution has 2,785,000 km (1,730,000 miles) of relatively small-diameter, low-pressure piping that includes 1,739,000 km (1,080,000) miles of distribution mains and 1,046,000 km (650,000 miles) of services. Many mains (57%) and service pipelines (46%) are made of steel, cast iron, or copper that are prone to corrosion. The total annual direct cost of corrosion was estimated to be 5 million. 

A large percentage of mains (57%) and services (46%) are metallic systems (steel/cast iron/copper), and corrosion is a major problem. For distribution pipe, external corrosion is the primary problem and internal corrosion has also been observed in some instances. The methods of corrosion monitoring on cathodically protected piping are similar to the methods used in the case of transmission pipelines... 

A large percentage (57%) of mains and services (46%) is metal (steel, cast iron or copper), and corrosion is a major issue. For distribution pipe, external corrosion is of primary importance, although internal corrosion has been noted in some cases. The methods of monitoring corrosion on cathodically protected pipe are similar to those in the transmission pipeline sector, including pipe-to-soil potential and coating surveys. One difference is that in distribution systems, leak detection is an acceptable method of monitoring for these pipelines without CP (nearly 15% of the steel mains). 

Selection of the anode in the case of impressed current CP system is primarily based on the dissipation rate of the anode. Low resistance to current flow, low dissipation rate, physical robustness, fabrication, and minimal cost are the desirable properties of candidate anode materials. Fligh silicon, chromium bearing cast iron has a low dissipation rate. Dissipation rate varies with the environment however, 0.5 kg/Ayear is a typical requirement for the impressed current CP of pipelines. 

Oil and gas have been known since antiquity because petroleum products were found naturally on the earth s surface. There are several references in the Bible related to asphalt and bitumen. Romans used oil for lighting and heating the thermae of Constantinople. Persians and American Indians for the extraction of petroleum, used blankets that were soaked in shallow pools of water and oil and then squeezed. In China and Japan, even before the Christian era, extraction was carried out with artificial wells lined with wood or masonry. Transport was carried out with buckets, but it seems that already in 250 BC, the Chinese used flammable gas as fuel, transported with bamboo poles, making them the first pipelines. In the same period, on the shores of Lake Titicaca, it seems that the Incas distilled oil in large earthen pots heated by the sunlight. In 1859, Drake began the modem age of oil extraction wells by using cast iron pipes [1-3]. 

Cast iron cannot be used in oleum service as it becomes brittle and the pipelines can leak suddenly. 

To avoid corrosion, cast iron, enamel or nickel-clad reactors, and plastic HCl pipelines (e.g. from phenol-formaldehyde resins or polyvinylidene fluoride) or glass or enamel pipes are employed iron Raschig rings are used as the catalyst, placed as a layer on the reactor base. 

Pipelines. This section deals only with off-site pipelines used for the longdistance transfer of brine. Some pipelines, especially among the older ones, are cast iron. Newer lines are more frequently carbon steel or even a resistant plastic. 

Brine pipelines H+/General Cast iron, carbon steel, FRP, PVC, PP,... 

A metal pipeline was unlikely to be satisfactory in this application. Cast iron would be expected to last perhaps 20-30 years, whereas the design life was to be 50 years. It would be subject to internal attack from the effluent and external attack from the sea water. Protection against this type of corrosion would be difficult. Similar objections apply to use of mild steel, where again predictable protection would be difficult to achieve mild steel would also suffer rapid internal corrosion. A suitable grade of stainless steel could probably be selected to resist internal attack by the effluent but the problem of external corrosion would remain. Stainless steel is subject to corrosion pitting in sea water, especially when the oxygen content is low. In quiet water the rate of pitting can be 6.9 mm per year. 

Distribution networks in towns have been built over periods of decades with various phases of pipeline technology. Networks can consist of welded steel pipes, steel pipes with lead sockets, different types of cast iron and plastic pipes. 

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