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# Stoichiometry Problem

6 replies to this topic

### #1 XBOX999

XBOX999

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Posted 31 January 2010 - 05:44 PM

Ammonia is to be scrubbed from a gaseous mixture of NH3, H2O and KCl in a gas absorber. Three streams (A, B and C) of different compositions are fed to a mixer prior to being sent to the absorber. The composition of stream A is 70 mass% NH3, 10 mass% H2O and 20 mass% KCl. The flow rate of stream B is 50 kg/h and the stream contains 10 mass% KCl and unknown compositions of NH3 and H2O. Stream C has a flowrate of 20 kg/h and contains 60 mass% NH3, 15 mass% H2O and 25 mass% KCl. The resultant stream after mixing (i.e. output from the mixer) contains 75.5 mass% NH3, 8.5 mass% H2O and 16 mass% KCl. The flow rate of the exit stream is 100 kg/h. Calculate the flows of all the unknown streams and the composition of stream B. Note: please express your answers in a tabular form using the streams as rows and the flows and compositions as columns.

### #2 breizh

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Posted 31 January 2010 - 07:06 PM

Hi ,
hope it helps .
Breizh

### #3 XBOX999

XBOX999

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Posted 31 January 2010 - 07:43 PM

Hi ,
hope it helps .
Breizh

thank you very much

### #4 fatimah

fatimah

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Posted 31 January 2010 - 07:54 PM

Dear XBOX999

the question is quite straight forward and do not involve any reaction. perhap next time you may try to calculate it by yourself unless you want to do cross checking.

### #5 Ford_Pain

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Posted 19 July 2012 - 04:32 AM

Hi ,
hope it helps .
Breizh

I tried 8 hours to solve it.But missing something.Can You help me please?
Thank You.

### #6 Neelakantan

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Posted 23 July 2012 - 05:54 AM

seeing the dates, i find the problem was originally posted two years back; and Ford_pain tried to solve and found it difficult;

let me try online now!

stream A (quantum unknown -- say X kg/hr); mass ratio 70:10:20; (Nh3: water: kcl)

Stream B (quantum 50 kg/hr;) mass ratio Y:90-Y:10; this means a mass flow of Y/2, 45-Y/2, 5 kg/hr respectively;

stream C (quantum 20 kg/hr); mass ratio of 60:15:25; mass flows 12, 3, 5 kg/hr;

total stream quantity is 100 kg/hr; that means 100=X+50+20; which means stream A is 30 kg/hr;

stream A: mass flows 21, 3, 6 kg;

total Nh3: 21+y/2+12 = 33+Y/2;

total H2O = 3+45-Y/2+3=51-Y/2;

total KCl= 6 + 5 + 5= 16 kg/hr

mass ratio in total stream = (33+Y/2):(51-Y/2):16 (calculated) = 75.5: 8.5:16 (given);

solving Y= 85;

total solution:

stream A is 30 kg/hr;

mass ratio in stream B 85:5:10

cheers!

neelakantan

### #7 kkala

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Posted 02 October 2012 - 01:47 AM

Results were elaborated during summer vacations but forgotten, since I had no connection to Web at that time. However I think it is useful to present them even now in the attached "stoiciometry.doc". They are actually same as neelakantan's, only wording is different (tabulation).