×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

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

Jobs

Optimum Carbon Bed Depth

Optimum Carbon Bed Depth

Optimum Carbon Bed Depth

(OP)
Trying to find the optimum liquid phase activated carbon bed depth for acid wash carbon (12 x 40 mesh).  Is there such a thing as a maximum bed depth in a vessel.  If so, what is the limiting factor (i.e. backwash flow, compaction of carbon, pressure drop, etc) ?

RE: Optimum Carbon Bed Depth

It will depend somewhat on the application.  

RE: Optimum Carbon Bed Depth

(OP)
Assume high purity water application (i.e. food and beverage)

RE: Optimum Carbon Bed Depth

If you have filtration rates of 4-6 gpm/square foot of bed area, the bed depth is typically 2 to 3 feet.

You should be replacing the bed on an annual basis. If you replacing the bed annual, there is no reason to install a deeper bed depth. A deeper bed depth will just give you a slightly higher pressure loss (~1 psi or so)across the filter with no improvement in water quality parameters.

RE: Optimum Carbon Bed Depth

Possibly you are trying to remove organics. Minimum bed depth is dictated by kinetics of adsorbtion reaction. This kinetics can be investigated in the lab with your water sample(and your organics) in the operating temperature. This is a must if you want to provide high purity water. In non critical applications, you can go with bimr rule of thumb: 2-3 ft depth.
The maximum depth can be calculated by Ergun formula to have a pressure loss around 5 psig for a clean bed.

RE: Optimum Carbon Bed Depth

(OP)
Thanks.  Do you happen to have a good reference that presents the Ergun formula for this calc ?

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!


Resources