How does temperature affect reflux ratio?

If the reflux rate is too high, too much liquid will flow down the column, and the column top will be cooled too much. A low reflux temperature leads to too much condensation of the rising vapour, again increasing the liquid level and the hydrostatic pressure.

What happens when you decrease reflux ratio?

Reflux ratio (RD = L/D) has a tremendous effect on both column tray efficiencies (at constant feed and distillate rates) and on the composition of the distillate and bottoms. A lower reflux rate greatly reduces the methanol purity of the distillate.

Why high reflux can be disadvantages for column operation?

The reflux ratio will modify the slope of operation line. Increasing reflux ratio would act in reverse i.e, it would have a disadvantage of increase in duty of condenser and reboiler as load increases. This increases the operation cost of distillation column, however, more enrichment is achieved.

Why is temperature important in fractional distillation?

The distillation towers have liquid outlets at intervals up the column which allow for the withdrawal of different fractions or products having different boiling points or boiling ranges. By increasing the temperature of the product inside the columns, the different products are separated.

What is the role of the condenser in the distillation?

In chemistry, a condenser is laboratory apparatus used to condense vapors — that is, turn them into liquids — by cooling them down. In distillation, a mixture is heated until the more volatile components boil off, the vapors are condensed, and collected in a separate container.

Why does the temperature on the thermometer decrease after collecting the first fraction before increasing to the second fraction?

After the first component completely boils off, the pot temperature increases until the next compound begins to boil off. During this time, vapors do not reach the thermometer (situated at the head) and the temperature drops slightly.

How does reflux ratio affect the number of stages?

When reflux ratio increases the number of stages of plate decreases. The Total reflux ratio can be defined as all reflux of distillate is fed to the distillation column to achieve desired enrichment of the component.

How does reflux ratio affect the performance of distillate distillation?

Increased reflux ratio improves separation and purity of the distillate. The price paid for this is increased “churn” as the same molecules get evaporated and condensed more times. Thus, reboiler heat duty, condenser heat duty, and column diameter all will increase with increased reflux ratio (though diameter change might be negligible).

Does subcooled reflux temperature affect distillation column process?

Also, you will understand the effect of subcooled reflux temperature on distillation column process. The reflux temperature is very important as this affects distillation column energy requirement and throughput as well. As we all know, distillation columns are widely used to separate the liquid mixture based on their boiling point difference.

What happens when we increase the reflux ratio of a column?

As we increase Refulx ratio, more and more, almost Condesate we have to route to column back. So number of plate for separation decreases but reboiler and condenser load will be maximum in case of Total reflux ratio. And as vapor load will be increased, diameter5of column will be increased.

What is the reflux temperature of condenser cooling water?

And, this subcooling can be around 6 – 8 0 C plus to the condenser cooling water outlet temperature. So, for our case condenser cooling water temperature is 36 0 C hence reflux subcooled temperature will be around 42 – 44 0 C.