In: Other

An equimolar mixture of A and B is flashed. What is the maximum possible liquid concentration of B in the product? Assume that A is more volatile and the relative volatility is 4.38.

The answer should be within 0.02 of the correct answer.

Given;

An equimolar mixture of A and B is flashed.

A is more volatile than B.

Relative volatility ; α = 4.38

As A is more volatile; all the calculations will be based on concentration of A.

Concentration of A in feed ; z = 0.5

Concentration of A in liquid product = x

Concentration of A in vapor product = y

As liquid and vapor product stream are in equilibrium; x and y are related as :

y = α x / (1 + (α - 1) x)

**y = 4.38 x / (1 + 3.38 x)**

Let the flowrate of feed , liquid and vapor streams be F, L and V respectively.

Overall material balance :

F = L + V

Therefore;

V = F - L

Component A balance:

z F = x L + y V

0.5 F = x L + ( 4.38 x / (1 + 3.38 x) ) (F - L)

Therefore;

(0.5 - 4.38 x / (1 + 3.38 x) ) F = (x - 4.38 x / (1 + 3.38 x)) L

which on simplification gives;

(0.5 + 1.69 x - 4.38 x) F = (x + 3.38 x^2 - 4.38 x) L

(0.5 - 2.69 x) F = 3.38 x (x - 1) L

**L / F = (0.5 - 2.69 x) / 3.38 x (x - 1)**

The concentration of A in liquid phase = x

Moles of A in liquid phase = L x

Moles of A in liquid phase per mole of feed = L x / F

Therefore;

Multiplying both sides in the equation by x :

L x / F = x (0.5 - 2.69 x) / 3.38 x (x - 1)

L x / F = (0.5 - 2.69 x) / 3.38 (x - 1)

To get the minimum amount of B in liquid phase; we need to find the minima point of the RHS.

Let f (x) = L x / F

Therefore;

**f (x) = (0.5 - 2.69 x) / 3.38 (x -
1)**

To get the minima of this function; we plot this function and check for any point of minima.

The plot of f(x) vs x is given below :

From the graph we can see that the non-negative minimum value of f(x) is 0. This occurs at x = 0.2

Therefore;

Minimum possible concentration of A in liquid product = 0.2

**Maximum possible concentration of B in liquid product =
0.8**

An equimolar liquid mixture of Benzene (B) and Toluene (T) at
20oC is fed continuously to a flash drum in which is
heated to 60 oC. The liquid product is 40 mole % B and
the vapour product is 60 mole % B. How much heat must be
transferred to the mixture 100 mol of feed.

A vessel contains a mixture of equimolar liquid benzene and
liquid toluene that is in equilibrium with their vapors and air.
The temperature of the mixture is 40 degrees celsius. The mole
fraction of air in the vapor phase is .6 or 60%. What is the total
pressure and the mole fraction of benzene in the vapor phase?

Nitrogen is bubbled through a liquid mixture that contains
initially equimolar amounts of benzene (B) and toluene (T). The
system pressure is 3atm and the temperature is 80 degrees Celsius.
The nitrogen flow rate is 10 standard liters per second. The gas
leaving the bubbler is saturated with B and T vapors.
(a) Estimate the initial rated (in mol/min) at which B and T
leave the bubbler.
(b) How will the mole fraction of B and T in the liquid...

Nitrogen is bubbled through a liquid mixture that contains
initially equimolar amounts of benzene (B) and toluene (T). The
system pressure is 3 atm and the temperature is 80C. The nitrogen
flow rate is 10.0 standard liters per second. The gas leaving the
bubbler is saturated with B and T vapors.
a) Estimate the initial rates (in mol/min) at which B and T
leave the bubbler.
b) How will the mole fractions of B and T in the liquid change...

An equimolar liquid mixture of benzene and toluene at 10C is
fed continuously to a vessel in which mixture is heated to 50C. The
liquid product is 40 mole%B and the vapor product is 68.4% B. How
much heat must be transferred to the mixture per mol of
feed?

What is the maximum concentration of carbon possible in the FCC
phase of iron before causing precipitation of either Fe3C or
liquid? At what temperature is the carbon solubility in FCC iron a
maximum?

Glucose-Fructose mixture concentration was 73 µg/mL. what is
the concentration of glucose in the mixture? total volume =
25ml

A closed system contains an equimolar mixture of n-pentane and
isopentane. a) Suppose the system is initially all liquid at 120°C
and a high pressure, and the pressure is gradually reduced at a
constant temperature. Estimate the pressures at which the first
bubble of vapor forms and at which the last drop of liquid
evaporates. Also calculate the liquid and vapor compositions (mole
fractions) at those two conditions. b) Now suppose the system
starts as a vapor at 1960 mm...

A mixture of ideal gases A (propane) and B (isopropanol) exist
in a vapor-liquid equilibrium in a constant temperature and
pressure container. Originally, there is 1 mol A and 1 mol B. The
mol fraction of A in the gas phase is 76% and 22% in the liquid
phase. Gases A and B start to flow into the system at constant flow
rates (at the same constant T and P). The flow rate of A is 3
mol/s. a. Calculate...

A liquid mixture had 30 moles of A and 70 moles of B. The vapor
pressure of pure A is 790 torr and pure B is 630 torr. What is the
pressure at which the mixture boils?

ADVERTISEMENT

ADVERTISEMENT

Latest Questions

- discussed big data , data warehouse and google database for big data and bootstrapping technique for...
- Why do multinational corporations use tax avoidance strategies even when it might be immoral? Explain at...
- An organization has the following password policies: - password must be at least 16 characters long...
- 1) The three-dimensional structure of a protein is determined by its primary, secondary, or tertiarty structures....
- Which of the psychotherapies discussed in the textbook do you think is most effective? Why? Discuss...
- A genetic experiment involving peas yielded one sample of offspring consisting of 416 green peas and...
- At the beginning of 2018, the aggregate output in Atlantis was $15 billion and the population...

ADVERTISEMENT