3 replies to this topic

[Isai]

What design considerations and calculations do i need to consider when designing 2 activated carbon adsorbers in series?

Data:
Stream is in liquid phase (HCl)

[Art Montemayor]

You haven't given sufficient basic data:

• What is the operating pressure and temperature?
• What is the flowrate of the stream being treated?
• What is the physical size of the adsorbers?
• Is the process steady state or batch?
• What is the purity of the HCL?
• What is being adsorbed (sorbate)?
• Why two adsorbers in series? (in other words, are 3 better? 4 super? 5 superlative? etc. etc.)
• Do you require adsorbent regeneration? If so, how? If not, is the spent adsorbent disposed and replaced?

Await your reply with some reasonable basic data.

[Isai]

I'm sorry for the late reply, pls see details below.
What is the operating pressure and temperature? 200kPa, 60Deg.C
What is the flowrate of the stream being treated?2.8 M3/HR
What is the physical size of the adsorbers?1.1M3 EACH, Material of construction, (fibre glass)
Is the process steady state or batch? STEADY STATE
What is the purity of the HCL? 30%
What is being adsorbed (sorbate)? ORGANICS (PARAFFIN & PARTIALLY CHLORINATED), CL2

Why two adsorbers in series? (in other words, are 3 better? 4 super? 5 superlative? etc. etc.)

We have 2 existing ones, so it would suit us to use what we have, COULD USE THEM AS A LEAD LAG TYPE.

Do you require adsorbent regeneration? If so, how? If not, is the spent adsorbent disposed and replaced?

At the moment it is disposed, but disposal costs are high. Any suggestions on regeneration?

[Art Montemayor]

Now that we are getting more data, the picture becomes clearer. Why couldn't we have had this at first? Anyway, you are handling a relatively small flow rate of relatively weak acid through two relatively large adsorption beds. You haven't said what quantity or % of impurities you are removing, but I would guess the total impurities adsorbed are well below 1% of the total flow rate of the weak acid.

You complicate the picture by bringing up the fact that the two adsorbers are existing since you said originally you are designing for two adsorbers in series. I don't understand what you are meaning to say. Do you mean that you are DUPLICATING the existing adsorber? That is different from designing new ones. The beds seem to be quite large in regards to the flow rate put through them. But you can design to any time cycle that you wish.

We don't have enough basic data to comment on whether the activated carbon can be regenerated. However, what I would do is I would pipe and valve the two adsorbers so that I could switch the second adsorber to receive the first pass of liquid when the carbon in the first adsorber is depleted. Here, I presume you are monitoring the purity (or degree of adsorption) coming out of the first adsorber and into the second. By switching the beds, I make the maximum use of the carbon before disposing of it. You may be doing that already, I hope.