3 replies to this topic

[S J]

Hello,

I'm senior process engineer and I'm studying for CDU desalting process and corrosion.

 

Currently, I found that,

in Petroleum Economics and Engineering, third edition,

it indicates that salts , particularly magnesium chloride , are hydrolyzed at temperatures above 120C and

in Troubleshooting process Operations (Lieberman), third edition,

it indicates taht MgCl2 and CaCl2 salts in crude oil decompose to HCl at temperature above 350F(177C).

 

Which one is correct hydrolysis temperature of MgCl2 to generate HCl ?

Please share your knowledge if any.

Edited by S J, 13 May 2016 - 02:36 AM.

[PingPong]

It is rather academic to worry about the exact temperature at which the first MgCl₂ (or CaCl₂) molecule will hydrolyse.

That starting temperature could be around 120 ^oC (250 ^oF) for MgCl₂, however it is not so that all MgCl₂ immediately hydrolyses at that temperature, but as the temperature increases further in the preheat exchangers downstream the desalter the percentage hydrolysis increases.

 

See for example Figure 1.16 in this book:

https://books.google...epage&q&f=false

[S J]

Thanks for your reply.

[daniwibowo8]

Dear PingPong,

 

Highly appreciate for prompt response and good citation.

 

Do you have any reference for hydrolysis of NaCl/MgCl2/CaCl2 to be fouling substance if desalter inlet temperature too high like below reaction:

 

CaCl2 (s) + H2O (l) --> CaO (s) + 2HCl (l) 

 

MgCl2 (s) + H2O (l) --> MgO (s) + 2HCl (l) 

 

NaCl (s) + H2O (l) --> NaCl (s) + H2O (l)

 

Thank you again.