Assignment 1

Question 1

Explain the component of the P-x,y diagram

Answer 1

x-axis = x1 and y1
y-axis = pressure

The upper line is bubble point

the lower line is the dew point

Between = VLE

Question 2

Describe raoult’s law

Answer 2

Raoult’s law argues that each component in an ideal liquid mixture has a partial pressure equal to the partial vapor pressure of the same component

yi * P = xi * Pi^sat

Question 3

When can the raoult’s law be used

Answer 3

If the mixture is ideal, which means the molecules are similar in structure

and if the vapoure is ideal: Low pressure and room temperatur (Not low)

Question 4

what is modified raoults law

Answer 4

The modified raoults law is used when the mixture is not ideal.

Her is γ and Φ considered as the deviation from ideality

yiPΦ =xiPi^satγi

Question 5

What is γ?

Answer 5

Activity coefficent

The deviation from ideality in the mixture

Question 6

What is Φ?

Answer 6

fugacity coefficent

The deviation from ideality in the gas fase

Question 7

Is there a way to determine if a solution is nonideal

Answer 7

Calculate γ and se if it = 1

Question 8

How can you determine the activity coefficent?

Answer 8

Wilson equation

Margules equations

Question 9

Which components is involved in Wilson and Margules equation. And how is they found

Answer 9

concentration of the liquid and 2 constants.

The constants is found by the gibbs free energy

Question 10

How is the gibbs free energy found

Answer 10

It is found by experiment, where the ln(γ) can be calculated and then find the gibbs free energy

Question 11

what is dew point

Answer 11

It is the point at which the first drop of the gas mixture (vapor phase) begins to condense

Question 12

what is bubble point

Answer 12

It is the point at which the first drop of the liquid mixture (liquid phase) begins to vaporize

Question 13

What is flash evaporation?

Answer 13

The feed is pressurized and heated and passes through valves into the flash drum. The feed then experiences a large drop in pressure which results in the vaporization of the liquid feed and the vapor taken off overhead. This results into two phases, the vapor phase with the most volatile species and a liquid with the less volatile species.

Question 14

What is found by the racket equation?

Answer 14

The molar volume for a liquid.

Question 15

What does the maximum vapour velocity equation consist of?

Answer 15

1. a constant (conditions)
2. correction
3. the densities of the liquid and vapour

Question 16

what components determine the size of the flash drum.

Answer 16

The cross section area, Diameter and liquid height (x2)

Question 17

Which component determine the size of the drum?

Answer 17

Volumen flow of the Liquid and vapour.

maximum vapour velocity

Liquid residence time