What can go wrong in distillation?
What can go wrong in distillation?
The distillation result is poor: the fractions obtained are not of acceptable purity. Typical problems: Distillation too fast. The components require time to separate. We need many evaporation-condensation cycles for good separation, and pseudo-equilibrium between vapor and liquid throughout the system.
How can the efficiency of a distillation column be improved?
Wrap the distillation column with an insulator like aluminum foil. The insulation will allow the vapors to travel all the way to the top of the column and out the condenser. The increase in efficiency results from the repeated interaction with the column packing.
What causes overpressure in distillation column?
A distillation column has a large input of heat at the reboiler and a large output at the condenser. If cooling at the condenser is lost, the column may suffer overpressure. Another hazard is overpressure due to heat radiation from fire. Again pressure relief devices are required to provide protection.
How does mass transfer occur in distillation?
On the trays or around the packings where the vapour and liquid came into contact, mass transfer takes place. Lower boiling point component (ethanol) from the liquid going down the column will be vaporized and transferred into the vapour that is going up the column.
What is weeping in distillation column?
what is weeping in distillation? Weeping is when liquid flows downward through the holes in a distillation tray. If the vapor rate is too low the liquid may be able to drop to the next stage through the holes, resulting in less than optimal vapor/liquid contact (and therefore less than optimal separation).
What is foaming in distillation column?
Foaming in a distillation column is the expansion of liquid that provides high interfacial liquid-vapor contact. This process decreases the vapor-liquid equilibrium, slowing down the distillation process. Excessive foam can have many causes.
What is the limitation of simple distillation process over fractional distillation process?
In a simple distillation, a fractionating column is not used, and vapor from the distilling flask goes straight into condensation. It only has one or two theoretical plates, so it would not be effective for the separation of mixtures like L1, which requires more than four vaporization-condensation cycles to purify.
What Cannot be removed from distillation?
Distillation removes heavy metals, micro-organisms, poisons, bacteria, contaminants, sediment, minerals and viruses. Distillation can not remove substances with lower boiling points than water including oils, petroleum and alcohol. The boiling chamber collects these contaminants and requires regular cleaning.
How can we improve the distillation process?
Adding inter-condensers and/or inter-reboilers can help improve overall energy efficiency. Pumparound, one of the inter-condenser concepts, has been widely applied to numerous petroleum multi-product fractionators. On the other hand, implementing an intermediate reboiler can reduce the main reboiler duty.
What affects distillation column efficiency?
The section efficiency in a distillation column is related to the tray efficiency by (2): When the equilibrium line is steeper than the operating line, as is typically the case for the stripping section of a column, the stripping factor is greater than one and the section efficiency is less than the tray efficiency.
How can we prevent flooding in distillation column?
Some of the more common methods used to eliminate flooding involve temporarily decreasing the feed rate, the reflux rate, or both, to reduce the amount of liquid in the column, and decreasing the vapour in the column by reducing the reboiler steam.