Q & A > Question Details
For an atmospheric distillation column designed for natural gas condensate as a raw material:
1. If HCL is found in thr boot water then what type of chemical dosing can be injected? Without injecting any wash water the pH remains 5.5 but when we inject water the pH reduces a little but remains within 5-5.3. Nonetheless, the corrosion is taking place without and with injection of wash water at the overhead line.
2. If boot water contains H2S then what chemical dosing should be used and what will be the injection point?
3. If pH depression is due to CO2 or organic acids then what should be the chemical dosing and what will be the injection point?
4. If there is iron in boot water then what should be the chemical dosing and injection point?

 
Answers
09/02/2021 A: Nagarathinam S Murthy, Ashphil Consultancy, Chennai, nssvdvr@gmail.com
Adding a filming amine when wash water is not being injected could be an ideal way to prevent corrosion. Talk to solution providers like Suez Water Technologies and Solutions. They can take a boot water sample, carry out ionic chromatography to understand the types of acidic species entering the overheads and suggest the right chemistry for a corrosion inhibitor with due understanding of no harm to the rest of the process and overhead product stream. Check the level of chloride in the boot water. If it is already well below say 10ppm, we may not need any neutralizer like ammonia solution or neutralizing amine.