1 reply to this topic

[roshimessi]

Dears

i see in vendor PID they use h2so4 mixed with water in inlet of  gas striping column, in this column sweet gas coming from below of the tower and water with h2so4 coming from top of the tower ,it use for reducing the percent of h2s from water,

the told us we use it for adjust the ph

but i have 2 question 

1-does it have any affect to make the scale in the line due to react with any water impurity such as "ca ,mg and...

2- is it normal  practice or not?

[S.AHMAD]

Hi

H₂S in sour water ionizes into H⁺ and HS^- as per following equation:

H₂S  =   H⁺  +  HS^-

The above equation is in equilibrium. Adding H₂SO₄ increases the H⁺ concentration therefore the reaction shifts to the left and thus the sour water liberates H₂S and improve the removal of H₂S from the sour water system.

The problem with H₂SO₄ injection is if the water hardness is high. This leads to formation of scale and results in fouling of heat exchangers even the tray/packing inside the stripper.

 

Use of H₂SO₄ is quite common in the industry for improving the H₂S removal in sour water stripping. My suggestion is to inject H₂SO₄ only when you have problem in removing the H₂S. Otherwise, do not inject if the H₂S level in the stripped sour water is within the environmental limit. You save cost.

Edited by S.AHMAD, 12 January 2014 - 09:43 PM.