Distillation - Basic Principles and Distillation - Basic System and Components

Select the choice that describes one way that a packed tower is different from a tower that has trays with bubble caps.

A packed tower contains layer of devices that have a lot of surface area.

The pressure exerted by the atmosphere on a liquid in an open container can be referred to as what?

External pressure

If the temperature at the top of the tower is lower than it should be, more of the heavier components will vaporize and become part of the overhead product, instead of flowing down the tower as a liquid should. T or F

False

In which state of matter are bonds holding the molecules to each other the weakest?

Gas

Select the choice the correctly complete the following sentence "A liquid with a high vapor pressure"............

Generally has a low boiling point

Substances with [_____] boiling points condense near the bottom of the fractionating column.

High

in illustration below is a closed container of liquid. Select the statement that in NOT true about the conditions in a closed container.

If vapor pressure increases, the boiling point will increase.

A mixture's boiling range is the temperature from its _______ to its ______.

Initial boiling point, Final boiling point

How are component that vaporizes last during distillation different from the component that vaporizes first?

It has a higher boiling point

in a single batch distillation process. What happens to the liquid that leaves the condenser?

It is collected in a receiver.

When a liquid, such as water or pentane, is heated to its boiling point and heat continues to be added, what happens to the liquid's temperature?

It stops increasing.

How is a distillation tower's differential pressure most likely to be affected if the condenser is plugged?

It will decrease.

If the rate at which vapors move up a distillation tower increases, what will generally happen to the tower's differential pressure?

It will increase.

What can be said about two components in a liquid mixture with a high relative volatility?

It's easy to separate them because their boiling points are far part.

What can be described as heat that is observed as a change in state, not as a change in temperature?

Latent heat

Which of these changes of state takes place during the distillation process?

Liquid to vapor

Select all of the characteristics of the component in a liquid mixture that vaporizes first during distillation.

Low boiling point

What will happen if the temperature at the bottom of a distillation tower is lower than normal?

Not enough of the lighter components will vaporize.

What is the term used to describe the product of a distillation system that contains primarily the lightest part of the original liquid mixture?

Overhead product

Select the choice that refers to the vapor pressure of an individual component in a liquid mixture.

Partial pressure

Which section of the distillation tower has the highest concentration of the lightest component?

Rectification section

Select the term that refers to the relationship between the boiling points of the components is a liquid mixture.

Relative volatility

What can best be described as "heat" that can be sensed and measured with a thermometer?

Sensible heat

Which type of distillation process in represented in the illustration below?

Single Batch

The bonds that hold liquid molecules to each other are ________ the bonds that hold vapor molecules to each other

Stronger than

The phrase used to describe the gradual decrease in temperature from the bottom of a distillation tower to the top is [_____ _______].

Temperature gradient

"Initial Boiling Point is" .........

The boiling point of the substance with the lowest boiling point.

Select the choice that is true for successive batch distillation.

The distillation occurs in more than one still.

Select the best definition of boil-up.

The heat that is added to the bottom of a distillation tower by a reboiler

Select the best definition of "external reflux."

The liquid pumped back into the top of a distillation tower

If two components in a liquid mixture have boiling points that are fairly close together, what can be said about the mixture's relative volatility?

The mixture has a low relative volatility.

"Boiling Range" is ........

The temperature range from a mixture's initial boiling point to its final boiling point.

What happens when vapors and liquid come into contact with each other on trays inside a distillation tower?

The vapors transfer some of their heat to the liquid.

In a single batch distillation process, what happens to the vapors from the boiling liquid?

They rise and move to a condenser.

In a distillation tower that uses trays, what is the purpose of the weirs?

To allow liquid to build up on each tray

In a typical distillation system, what is the purpose of the preheater?

To heat the feed before it enters the tower

What is the purpose of reboiling in a distillation system?

To maximize product purity

What is the purpose of refluxing in a distillation system?

To maximize product purity

What will happen in a distillation tower if the temperature at the feed point is too high?

Too much of the heavier components will vaporize.

The lower the feed tray is in the tower, the lower it temperature will be. T or F

True

________ is defined as 'the heat that is added to the bottom of a distillation tower by the reboiler.'

boil up

Select one way that the temperature at the top of a distillation tower can be decreased.

by increasing the reflux rate

If the rate at which vapors move up a distillation tower decreases, what will generally happen to the tower's differential pressure?

it will decrease

The _____ is the component in the distillation system used for heating feed before it enters the tower.

preheater

________ affects the boiling temperature of a liquid.

pressure

Some distillation systems contain equipment known as _________ which pump hot liquid to a cooler and return it to the tower. It also helps control the temperature of internal reflux.

pumparound

____________ hydrocarbons travel further up the fractionating column before they condense because the have __________ boiling points. Select from the word below to fill the blanks.

smaller, lower

The section of the distillation tower below the feed point is called __________.

stripping section

_______ and _______ are the two process variables that affect changes in state during distillation.

temperature and pressure

Distillation is a process .......

that uses heat to separate two or more substances in a liquid mixture.

Select the statement below that complete the following sentence. "Final boiling point is ..........."

the boiling point of the substance with the highest boiling point

Select all the places in distillation tower where temperature control is important.

-At the feed point -At the top of the tower -At the bottom of the tower

Select all the ways to control the temperature in a distillation tower.

-Control the temperature of the feed. -Control the boil-up rate. -Control the reflux rate.

The illustration below is a closed container of liquid. Select all of the statements that are true about conditions in a closed container.

-More vapor molecules will create more vapor pressure. -Some vapor molecules condense and return to the liquid -Pressure is exerted by vapor molecules escaping from the liquid.

From top to bottom, the three zones of the distillation tower are

-Rectification section -Flash zone -Stripping section

Select alll the the things that happen when heat transfer takes place on the trays in a distillation tower.

-Some of the lighter components of the liquid vaporize. -Some of the heavier components of the vapors condense.

Select all of the choices that are NOT factors in determining the state of a substance.

-The number of molecules -The weight of the molecules

Select all of the factors that influence the state of matter in which a substance exist.

-The strength of the bonds between its molecules -The speed at which its molecules are moving

Select the changes of state that take place during the distillation process

-Vapor to liquid - Liquid to vapor

Select all of the choices that describe changes in states of matter that occur during distillation.

-Vaporization -Condensation

What is the term used to describe the product of a distillation system that contains primarily the heaviest part of the original liquid mixture?

Bottoms product

Select the choice that is NOT typically monitored for temperature control in a distillation system.

Bubble caps

Some distillation towers have _________ mounted over the opening on each tray.

Bubble caps

The different between the pressure at the bottom of a distillation tower and the pressure at the top of the tower is referred to as what?

Differential pressure

What can be described as the process that uses heat to separate two or more substances in a liquid mixture?

Distillation

Select the best definition of fractionation.

Distillation that occurs at different levels in a tower

What happens to a liquid when it is heated to it boiling point?

Vapor forms in the liquid and escapes from the liquid's surface.

What is internal reflux?

Vapors that condense and flow down inside a distillation tower

The _____ is the component in the distillation system used for cooling vapors.

condenser

Different hydrocarbons in crude oil have different boiling points, so they can be separated by fractional ___________.

distillation

[_____] are the devices that channel liquid from tray to tray inside a distillation tower?

downcomers

The middle section of a distillation tower commonly called the [____ ______].

flash zone

______ is the term used to describe distillation that takes place at different levels in the tower.

fractionation

Select the choice that correctly completes the following sentence. "In general, a liquid with a low vapor pressure .............."

has a high boiling point

What happens to the vapor pressure of a liquid when its temperature increases?

it increases

How is the component that vaporizes first during distillation different from the component that vaporizes last?

it is lighter

In the simplified continuous distillation process represented by the illustration below, what eventually happens to most of the heavier component of the original liquid mixture?

it is removed from the bottom of the column