Troubleshooting corrosion

Would more data Kelp clarify the relationships among frequency, speet and temperature If so. in what temperature should the data be obtained Pick an insect, and explain how you would carry out the experiment t obtain more data. [For an alternative to this problem, see CDP3-Ab.] Troubleshooting, Corrosion of high-nickel stainless steel plates was found t occur in a distillation column used at DuPont to. separate HCN and water. Su furic acid is always added at the top of the column to prevent poly men zatio of HCN. Water collects at the bottom of the column and HCN at the top. Tit amount of corrosion on each tray is shown in Figure P3-5 as a function c plate location in the column. 

Safety, environmental protection, and equipment protection (see Section 16.7 this could include redundant temperature sensing and alarms on reactors and reboilers handling corrosive chemicals such as HF), smooth operation, product quality, profit, monitoring, diagnosis, and troubleshooting. Identify the objective and select a pertinent variable. Direct measurement of the variable is preferred. If direct measurement is impractical, select an inferential or calculated variable. For example, temperature can infer conversion and composition. 

Corrosive wear can usually be identified by a pitted, worn surface. The best solution to corrosive wear is to eliminate the corrosive component from the compound. However, this is often not possible for other reasons. In this case, one has to use corrosion-resistant materials of construction, such as stainless steel. Inconel, Hastelloy, etc. In order to select the best material of construction, one should know the chemical species that are causing the corrosive attack. Various metal handbooks contain information about the chemical resistance of many metals against a number of chemical species. Figure 11.12 shows a flow chart that allows systematic troubleshooting of wear problems. 

FIG. 7—LP turbine troubleshooting Instrumentation that can identify chemical and corrosive conditlone. 

The superficial result of an acid carry-over is a sudden increase in corrosion and fouling. This is true whether the cause is of chemical or physical origin. The first step in troubleshooting such an incident is to check the following ... 

Refinery management, 524-525 Refinery metallurgy, 415-429 metals used in refinery service, 415-416 stainless steel nomenclature, 416-418 corrosion resistance, 417, 419—426 embrittlement dangers, 426 rigorous service, 426-427 heat-exchanger tube fouling, 428 troubleshooting problems, 428... 

Troubleshooting and corrosion prevention are covered in many standard texts [1,2,4-8]. 

Smith, P. 2005. Piping Materials Guide. New York Elsevier Gulf Professional Publishing. Print and electronic. Covers the selection of piping materials, materials and fitting, troubleshooting techniques for corrosion control, and inspections. 

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