Removing activated carbon from glycerine: which separation device is commonly used to remove fine carbon particles after decolorization?

Introduction / Context:
Activated carbon is often used to decolorize glycerine and other viscous liquids. After contact, the fine carbon must be removed to restore clarity. The separation method must capture fine, porous particles efficiently without degrading product quality.

Given Data / Assumptions:

• Liquid: glycerine (viscous but filterable with pressure).
• Suspended solid: fine activated carbon.
• Objective: high clarity, low residual fines.

Concept / Approach:
Plate and frame pressure filters excel at capturing fine solids, especially when aided by a precoat or filter aid to prevent blinding and improve clarity. Rotary vacuum filters are more suited to larger throughputs and coarser cakes; achieving carbon-level clarity is challenging. Centrifuges struggle with very fine, low-density carbon which does not readily cake under centrifugal force.

Step-by-Step Solution:
Match solid properties (fine, porous carbon) to separation mechanism—depth/surface filtration under pressure.Select plate and frame; precoat as needed.Exclude vacuum filter (clarity limits) and centrifuge (inefficient capture of fine carbon).

Verification / Alternative check:
Process manuals recommend pressure leaf or plate-and-frame filters with filter aids for carbon removal from viscous syrups and glycerine.

Why Other Options Are Wrong:
Rotary vacuum: lower clarity, risk of carbon bleed-through.Basket centrifuge: poor capture of ultrafines like activated carbon.

Common Pitfalls:
Skipping precoat/filter aid leads to rapid blinding and unacceptable filtrate turbidity.

Final Answer:
Plate and frame filter