Question

Sorry this is a HUGE problem and I don't even know where to start with this one. Any help is greatly appreciated! I rate any correct answers

thank you!

A 50/50 mixture of 1-propanol and 2-propanol is separated by a continuous single-stage equilibrium flash tank. The liquid entering the tank is at 89.0°C The tank operates at 70.00°C and 330.0 mmHg and both product streams emerge at these conditions Vapor product ny mol yy mol 1-propanol/mol 70.00°C, 330.0 mmv mol 2-propanol/mol 1 mol basis Liquid feed at 89.0℃ z1 0.5 mol 1-propanol/mol z2 0.5 mol 2-propanol/mol Liquid product nu mol x1 mol 1-propanol/mol x2 mol 2-propanol/mol The vapor pressures of 1-propanol and 2-propanol are given by the Antoine equation and the mixture follows Raoult's law. Within the process conditions, the specific enthalpies of 1-propanol and 2-propanol are given in the equations below heat, Q (h HI-1-0.2x7(°C) + 5.2 1- propanol mol 2-propanoli2c-70294 0.281 × Tło CI-7.0294 1- propanol H |--| = 0.0849 × Tl。C) + 53.577 mol (») HIM-0.0769 -l 2- propanol = 0.0769 × T( C) + 34.778 mol Find the composition of the product streams, the moles in each product stream (using a 1 mole feed basis), and the required heat input, Q, by doing the following steps. How many unknowns are there in the above process flow diagram? Number Which independent equations and balances can you write to solve for the process unknowns? A 1-propanol mass balance around the flash tank. A 2-propanol mass balance around the flash tank. Summation of the mole fractions of vapor product stream. Summation of the mole fractions of the liquid product stream Summation of the mole fraction of the liquid feed stream. Energy balance around the flash tank. The Antoine equation and Raoult's law to relate x to yi The Antoine equation and Raoult's law to relate x2 to y2 A mass balance on the liquid 1-propanol entering and leaving the flash tank. A mass balance on the liquid 2-propanol entering and leaving the flash tank. What is xi, the mole fraction of 1-propanol in the liquid product stream? What is x, the mole fraction of 1-propanol in the liquid product stream? Number mol 1- propanol/ mol What is y, the mole fraction of 1-propanol in the vapor product stream? Number mol 1 propanol mol What is nL, the moles of liquid product? Number mol What is nv, the moles of vapor product? Number mol What is Q, the heat inputted into the flash tank? What is Q, the heat inputted into the flash tank? Number kJ Consider the operating pressure of the flash tank, and its affect on the product streams. Is there a minimum operating pressure for the given inlet concentration and flash tank temperature? If so, what is this minimum operating pressure? Yes, there is a minimum operating pressure No, there is not a minimum operating pressure Number mmH min Is there a maximum operating pressure for the given inlet concentration and flash tank temperature? If so, what is this maximum operating pressure? Yes, there is a maximum operating pressure No, there is not a maximum operating pressure. Number mmHg max

Answer 1

Antoine Equation is given below

og10pA-+T

where p = vapour pressure (in bar), T=temperature (in K) and A,B,C are Antoine's constant.

Check the values of A,B,C and T from your source, put the values and obtain the vapour pressure for 1-propanol (p₁*) and 2-propanol (p₂*)

From my source I get p₁* = 244.85 mm Hg and p₂* = 443.95 mm Hg

1) There are 7 unknowns namely,

n_v, n_L, y₁, y₂, x₁, x₂ and Q

2) Except for the last two we can apply all the independent equations. These are

a) nv y1 + nL x1 = 0.5

b) nv + nL = 1

c) y1 + y2 =1

d) x1 + x2 = 1

e) x1 p1* = 330 y1

f) x2 p2* = 330 y2  

g) Energy balance

Q = Hout - Hin

Hin = 20.4898

From Liquid: Hout = 19.2 x1 + 12.6406 x2

From vapour Hout = 59.52 y1 + 40.161 y2

Therefore, 19.2 x1 + 12.6406 x2 + 59.52 y1 + 40.161 y2 - 20.4896 = Q

3) Solving c, d, e and f we get,

x1 = 0.72 and x2 = 0.28, y1=0.60 and y2 = 0.40

4) Putting these in a and using b we bet