Question

In: Chemistry

1000 mol/min of a mixture of 90 mol% air and 10 mol% HCl enters an absorber...

1000 mol/min of a mixture of 90 mol% air and 10 mol% HCl enters an absorber column and is contacted with a stream of pure water entering the column at the rate 300 moles/min. 90% of HCl in the feed gas is absorbed by water. The two exit streams are gas stream (air+HCl) and liquid stream (water+HCl), respectively.

1. Draw and label a flowchart.

2. Define a basis of calculation.

3. Carry out a degree of freedom analysis and determine flow rates in mole/min and compositions in mole fractions of the exit streams.

Solutions

Expert Solution

1. Flowchart

2. Basis of calculation

Purpose of the process: To prepare aqueous mixture of HCL + water.

Required calculations: Finding the mass flow rates of streams 1 and 2 and composition of stream 3 and 4.

Material Balance Equations: There are 4 independent material balance equations:

Total mass balance ? m₁ + m₂ = 1300 mol/min
air (g) + Hcl (g) balance ? (1000mol/min) m1
water balance ? (300mol/min) m2

3 . Since there is no chemical reaction, the generation and consumption terms are zero, and the balance equation for steady-state physical process will be:

Input = Output

There are two unknowns - Input HCl(g) and output HCl(aq.) - and since there are two substances - HCl and H2O - in the input and output streams, two balances may be written to solve for them. The total mass balance and the water balance involve both unknowns, but the Hcl balance involves only one.

HCl Balance

mol% In = mol% out

1000 mol/min of mixture contains 10% HCL (g) = 1000 x 10 /100 = 100 mol/min HCl (g)

90% of HCl(g) absorbe in water stream moving in 300mol/min

therfore

the actual HCl (g) dissolve in water stream = 100 x 90 / 100 = 90 mol/min (in aqueous solution)

The concentration of HCl (g) remains in gas stream (Out stream)

HCl (g) In stream = HCl (aq) + HCl (g)

100 mol/ min = 90 mol/min + 10 mol/min

Degree of freedom analysis:

A problem with just the right amount of information is uniquely specified. A degree of freedom analysis is used to determine whether a process is uniquely specified.

To perform a degree of freedom analysis for a given system, we must know:

N(_unknown)

find the number of unknowns in the problem

+N(_reaction)

add the number of reactions in the system

-N(_material)

subtract the number of independent material balances

-N(_other)and subtract the number of other relationships given in the problem statement
If N_dof equals zero, the problem is uniquely specified. If is N_dof greater than zero, the problem is underspecified. Finally, as you may have guessed, if N_dof is less than zero, the problem is overspecified.

For this examples N _dot equals Zero.

queen_honey_blossom answered 1 year ago

Next > < Previous

Related Solutions

A mixture of 0.2063 mol of Cl2, 0.2093 mol of H2O, 0.1887 mol of HCl, and...

A mixture of 0.2063 mol of Cl2, 0.2093 mol of H2O, 0.1887 mol of HCl, and 0.09871 mol of O2 is placed in a 1.0-L steel pressure vessel at 575 K. The following equilibrium is established: 2 Cl2(g) + 2 H2O(g) 4 HCl(g) + 1 O2(g) At equilibrium 0.05821 mol of O2 is found in the reaction mixture. (a) Calculate the equilibrium partial pressures of Cl2, H2O, HCl, and O2. (b) Calculate KP for this reaction.

Air flowing at 1000 ft3 /min, 66°F, and 1 atm enters a heat exchange unit and...

Air flowing at 1000 ft3 /min, 66°F, and 1 atm enters a heat exchange unit and exits at 76°F and 1 atm. Saturated steam at 12 psia is used to heat the air and leaves the unit operation as saturated water at 12 psia. The system is not adiabatic and heat is lost to the surroundings at -3 Btu/lbm steam condensed. Calculate the mass flow rate of the steam.

find the pH in a mixture of: a) 50 ml 0,10 mol/L HCL and 10 mL...

find the pH in a mixture of: a) 50 ml 0,10 mol/L HCL and 10 mL 0,50 mol/L NaOH b) 50 mL 0,10 mol/L HCL and 20 ml 0,50 mol/L NaOH c) 100 mL 0,20 mol/L CH3COoH and 50 mL 0,20 mol/L NaOH thx

A gas mixture consisting of 10% ethylene gas (C2H4) and 90% CO2 by mol is combusted...

A gas mixture consisting of 10% ethylene gas (C2H4) and 90% CO2 by mol is combusted with 50% excess air via the following unbalanced reaction: C2H4 (g) + O2 (g) à CO2 (g) + H2O (g) Air for the reaction is brought in from outdoors and cooled through a chiller to remove any humidity. The combustion product gas is pressurized so that all water vapor is condensed into liquid, which then combines with the water from the air chiller and...

A gas mixture consisting of 10% ethylene gas (C2H4) and 90% CO2 by mol is combusted...

A mixture of 6.92e-02 mol of Cl2, 2.15e-02 mol of H2O, 6.78e-02 mol of HCl, and...

A mixture of 6.92e-02 mol of Cl2, 2.15e-02 mol of H2O, 6.78e-02 mol of HCl, and 5.04e-02 mol of O2 is placed in a 1.0-L steel pressure vessel at 1447 K. The following equilibrium is established: 2 Cl2(g) + 2 H2O(g) 4 HCl(g) + O2(g) At equilibrium 1.43e-02 mol of H2O is found in the reaction mixture. Calculate the equilibrium pressures of all gases in the reaction vessel and the value of KP for the reaction. Pick the correct statement...

A mixture of 20.0 mol% benzene, 5.00 mol% toluene, and 75.0 mol% air is compressed isothermally...

A mixture of 20.0 mol% benzene, 5.00 mol% toluene, and 75.0 mol% air is compressed isothermally at 70 degrees C until condensation first appears. What is the mole fraction of benzene in the condensate? You may assume that air is noncondensable (and thus its vapor pressure is large) and this system obeys Raoult's Law. Note: when solving Antoine's equation it is best to keep all sig figs through calculation and then truncate them at the end. Question options: 0.605, 0.832,...

Propane burns with 15% excess air. Before the propane-air mixture enters the burner, air preheats from...

Propane burns with 15% excess air. Before the propane-air mixture enters the burner, air preheats from 32 F to 575 F. Determine the requirements of the preheater (BTU / h) if the amount of propane fed to the burner is 1.35x105 SCFH (standard cubic feet per hour) Note: In this case, take standard conditions in the natural gas industry, such as 60 F and 1 atm. Report: a) Flow diagram of the complete process and its table of material balance...

10. A mixture of 0.08729 mol of H2O, 0.1041 mol of CH4, 0.08069 mol of CO,...

10. A mixture of 0.08729 mol of H2O, 0.1041 mol of CH4, 0.08069 mol of CO, and 0.1098 mol of H2 is placed in a 1.0-L steel pressure vessel at 1034 K. The following equilibrium is established: 1 H2O(g) + 1 CH4(g) 1 CO(g) + 3 H2(g) At equilibrium 0.06283 mol of CO is found in the reaction mixture. (a) Calculate the equilibrium partial pressures of H2O, CH4, CO, and H2. Peq(H2O) = ____ . Peq(CH4) = ____ . Peq(CO)...

3.70 kg / min of air as ideal gas enters a steady state compressor that runs...

3.70 kg / min of air as ideal gas enters a steady state compressor that runs adiabatically. Air enters P1 = 300 kPa and T1 = 440 K and exits at P2 = 500 kPa. If the isentropic efficiency of the turbine is 0.876, what is the work, in kW?

Subjects