Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here


PH and ORP Control Strategy for H2S Removal in a Packed Bed Scrubber

PH and ORP Control Strategy for H2S Removal in a Packed Bed Scrubber

PH and ORP Control Strategy for H2S Removal in a Packed Bed Scrubber

We have a packed bed wet scrubber for H2S removal from our offgas. Two control strategies were installed by the manufacturer: Peroxide to control ORP and NaOH to control PH. Both are independent of each other. Both the ORP and PH are measured in, and NaOH and Peroxide added to the recirculating line going to the top of the column. These two control strategies inteact. The peroxide causes the PH to drop like a rock and the NaOH affects the ORP. My strategy is this: Controlling PH is more important than controlling ORP and Peroxide affects the PH more than NaOH affects the ORP. So I am thinking of controlling the PH to a setpoint and the ORP to a setpoint range. I am also  thinking that I can either use Feed Forward or use a Ratio control strategy. Any thoughts? What are people doing in industry?

RE: PH and ORP Control Strategy for H2S Removal in a Packed Bed Scrubber

As concentrated (50%) hydrogen peroxide is very acidic [pH of 1-3 per MSDS from FMC], try neutralizing the make-up solution. Although this will increase the volume of peroxide solution added, the amount of NaOH solution will ~proportionally decrease. Also, you'll get finer ORP control (e.g., less overshoot) using more dilute make-up solution.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close