Q1. (i) Explain how a film forming inhibitor protects a carbon steel pipeline from CO2 corrosion. (ii) Name 2 key factors that affect the performance of a film forming inhibitor in the pipeline
Q1. (i) Explain how a film forming inhibitor protects a carbon steel pipeline from CO2 corrosion.
(ii) Name 2 key factors that affect the performance of a film forming inhibitor in the pipeline
Q2. Explain how you would prepare a steel surface prior to the application of a coating system and what quality control methods you would apply
Q3. (i) Explain the principle of sacrificial anode cathodic protection for a steel pipeline buried underground, with a clearly labelled diagram, showing the direction of flow of the current.
(ii) For which applications is impressed current cathodic protection used?
Q4. For an FPSO (Floating Production, Offtake & Storage) vessel operating in the North Sea:
- Describe two examples of corrosion
mechanisms that can occur to the hull
(ii) Suggest practical ways in which your two examples of corrosion may be
controlled or mitigated for the hull.
Q5. (i) Describe the principle of LPR to monitor the corrosion rate in an aqueous solution
(ii) Describe 2 other (different) methods commonly used for direct corrosion monitoring
(iii) Why would you not use LPR to monitor corrosion in an oil producing system?
(c) Most types of metal corrosion are galvanic in nature. What are the fundamental requisites for galvanic corrosion to occur?
(d) How is electricity generated and conducted through a corrosion circuit?
Comment on the suitability of the following combinations of materials for oxygenated seawater service. You may refer to the RGU Galvanic Series for Metals and Alloys in Seawater for this question.
(i) 17-4 PH flange and graphite gasket (2)
(ii) CDA 675 flange and 410 stainless steel sealing ring (2)
(iii) Inconel 825 tube and Inconel 625 connector (2
(iv) 316L stainless steel pipe and 90-10 Copper-nickel sprinkler (2)
(b) Define ’’hot-dip galvanising’’ and explain how it works. (6)
(c) (i) Explain how a film forming inhibitor protects a carbon steel pipeline from CO2 corrosion. A sketch would assist the explanation. (2)
(ii) Name TWO key factors that affect the ability of a film forming inhibitor to adhere to the surface of the pipeline. (2)
(d) Discuss the effects of solution resistance on the Evans diagram. (2)
(a) Describe with illustrations and equations the following forms of corrosion:
(i) Crevice corrosion; (3)
(ii) Intergranular corrosion. (3)
(iii) What steps can be taken to mitigate against crevice corrosion occurring?
(c) Calculate the tendency for corrosion to occur in the following metal electrolyte systems, identifying the anodic and cathodic reactions:
(i) silver in cupric acid; (3)
(ii) nickel in silver nitrate. (3)
E0 Ag/Ag+ = -0.799V vs SHE, E0 Cu2+/Cu = -0.377V vs SHE, E0 Ni/Ni2+ = 0.250V vs SHE
Disclaimer: Please Answer all in details.
Step by step
Solved in 4 steps
