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[SR23]

Hi, I'm a first year chemical engineering student and I've had a go at this question but can't seem to get the right answer. Any help would be much appreciated. 

 

Glucose liquor containing 40.66 wt% glucose, 9.53 wt% unspecified polysaccharides and

49.81 wt% water is fed to a reactor and undergoes isomerisation. If this reactor feed is

comprised of a fresh feed input and a recycled reactants stream, calculate the recycle ratio.

 

Stream mass fractions

Fresh Feed 

Glucose: 55%

Polysaccharides: 5%

Water: 40%

Recycle Stream

Glucose: 18.1%

Polysaccharides: 20.3%

Water: 61.6%

[Francisco Angel]

Dear kkg14:

This kind of problems are usually worked like this, lets call I, the flow into the reactor, F the fresh stream and R the recycle stream. Based on the glucose concentration we have:

 

F*G_F+R*G_R=(F+R)G_I

 

We want the recycle ratio, which is basically a ratio of flows, so for example, we divide by R:

 

(F/R)*G_F+G_R=(F/R+1)G_I

 

Plugging the values:

 

(F/R)*0.55+0.181=(F/R+1)0.4066

 

Now you can get the ratio (F/R). You can use other component as reference, and you should get the same ratio IF the data are consistent.

 

I'm sure you can carry out the calculation process by yourself.

 

Best regards.