Pipes corrosion

Figure 8.10 A large, ragged perforation in a region of severe internal wastage on a copper pipe. Corrosion was caused hy ammonia-containing condensate.

Metal particles from wear and rust particles from reservoir and oil piping corrosion can lead to premature equipment failure and oil deterioration. It is important to provide suitable filtering equipment to remove these particles from the system. 

Murray, A. S., and W. E. Holman, How to detect and control drill pipe corrosion, World Oil, January 1969. 

Applies to essentially noncorroded piping. Corrosion can sharply decrease cyclic life therefore, corrosion resistant materials should be considered where a large number of major stress cycles is anticipated. 

Often plant personnel do not appreciate piping as well as it should be. As many chemical plants grow older, more piping corrosion problems will occur. It is critical that piping be regularly inspected so that plant personnel are not surprised by leaks and releases. 

It was shown above that the limiting c.d. increases with velocity raised to the 0.8 power and the pipe diameter raised to the -0.2 power for piping corrosion rates that are controlled by mass transport. In contrast, it is evident that the shear stress increases with the fluid velocity raised to the 1.75 power and the pipe diameter raised to the -0.2 power. Thus equality of shear stress does not give equality of mass transfer rates. In both cases corrosion is enhanced in pipes of smaller diameter for the same solution velocity. Such a relationship can be rationalized based on the effect of pipe diameter on the thickness of the mass transport and hydrodynamic boundary layers for a given fixed geometry. Cameron and Chiu (19) have derived similar expressions for defining the rotating cylinder rotation rate required to match the shear stress in a pipe for the case of velocity-... 

Visual inspection and the results of metal ion content in water samples, shows internal pipe corrosion in various locations in the hot water distribution system that compromises the quality of hot water. The cause of the internal pipe corrosion can be attributed to the following factors or a combination of the factors. 

In almost all the failures, including failure of the service saddle on an asbestos-cement 10-inch water pipe, corrosion from the soil side was to great extent responsible for the failures. 

Considering calcite equilibrium a pHc of 7.076 results, that is 0.376 pH units above the measured pH value of 6.7. The permitted deviation of 0.2 is exceeded. Since pH-pHc is negative, the water is calcite aggressive, i.e., it can still dissolve calcite and present a danger for pipe corrosion. Undersaturation can also be determined without calculation of the pHc, because within initial solution calculations in the PHREEQC output, calcite already shows a saturation index of -0.63 (= 23% saturation). 

If a proportion of the water from the old well is too high, the mixed water shows sulfate and nitrate concentrations exceeding drinking water standards (bold), if it is too low, the mixture is calcite aggressive (bold), which may lead to pipe corrosion. The optimum ratio is between 40 60 to 60 40, where the water can be discharged to the drinking water distribution net without any further treatment. 

With respect to the older Monsanto/Lummus AlCl3-catalyzed EB process the advantages are the lower costs and risks (i) in the handling and disposal of the aluminum chloride catalyst and waste and (ii) for equipment and piping corrosion and fouling (major equipment pieces needed to be replaced on a regular schedule because of corrosion). 

Figure 10.9 Rate of concrete sewer pipe corrosion as a function of surface pH. (Data generated by the Los Angeles County Sanitation District.)...

Control of annulus and pipe corrosion by maintaining a high pH. 

V. L. Barantsevich, L. V. Barakove, and I. A. Tribunskaja, Investigation of the Heat Pipe Corrosion Resistance and Service Characteristics, Proc. 6th Int. Heat Pipe Conf, Grenoble, France, pp. 188-193,1987. 

The specifications include a print of the process flow diagram showing special piping materials such as glass-lined pipe, alloy pipe, high-pressure pipe, corrosion allowances, etc. 

The built-in costs of corrosion of automobiles were identified as corrosion protection for steel body panels such as metallic zinc coatings, paint, adhesives and sealants, nonferrous metals, corrosion-resistant materials, rust-proofing heat exchanger components, mufflers, and tail pipe corrosion. The greatest impact on the cost of corrosion for automobiles was the adverse effect of corrosion on the cost of replacement of the automobile. Both the lO model and focused sector study showed that in both models the cost of replacement of the automobiles dominated the total cost and avoidable cost estimation. 

For gas distribution piping, corrosion mitigation is primarily sacrificial CP. ILI is not feasible for the relatively complex network of distribution mains and services. This makes integrity assessment of the piping somewhat difficult. 

M. Kimura, N. Totsuka, T. Kurisu, K. Amano, J. Matsuyama, Y. Nakai, Sulfide stress corrosion cracking of line pipe, Corrosion 45 (1989) 340-346. 

The primary applications of PVC include hot water and/or steam condensate piping, corrosive chemical piping at elevated temperatures, valves, fume ducts, internal column packing, and miscellaneous fabricated items. Reference [2] provides detailed information on CPVC piping. 

Only two types of scavengers are being marketed to the drilling industry currently (1) zinc-based chemicals and (2) iron-oxide (Fe304). Copper compounds, although used in the past, are not considered satisfactory today because of drill pipe corrosion caused by reaction of copper ions with iron. This will be fully discussed in subsequent sections. 

Dynacet 211 Dynacet 212 coating resin, pipe corrosion-resistance... 

Product contamination leaking valves/crud left in storage tanks/crud left in dead legs in piping/corrosion products/unexpected chemical reactions/sampling fault/ analysis fault/unexpected solubility effects. 

If insulating joints are installed in the above-mentioned pipe in order to reduce stray-current pickup, corrosion is now focused on the water side of the joint where any current that persists leaves the pipe to enter the water. Or, if a high-resistance joint exists between two sections of a buried pipe, corrosion may be more pronounced on the side where current enters the soil (Fig. 12.3). 

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