Chemical Engineering Answers

A step change of magnitude 10 is introduced into the transfer function

Y(S)/X(S)= 4/(2S²+0.3S+0.5),

find the following

a. Percent overshoot.

b. Rise time

c.Maximum value of y(t)

d. Ultimate value of Y(t)

e. Period of oscillations.

Explain briefly with step by step process.

1. A mixture containing 10% ethanol (E) and 90% H₂O (W) by weight is fed into a distillation column at the rate of 106.26 kg/h. The distillate (top product) contains 94.01 % ethanol and the distillate is produced at a rate of one tenth of that of the feed. 
2. _{Draw and label a flow chart of the process before solving the problem. Perform material (total) and ethanol balances to calculate the mass fraction of ethanol in the bottom product to at least four decimal places.} 

Liquid reactant decomposes as per the following reaction scheme: A→R, A→S with rates rR= k1CA^2₁ , rs=k₂CA The rate constants are k=0.4 m³/mo min and k=2 min³. An aquecus feed of containing A with CAo =40 mol/m³ enters a reactor, decomposes, and a mixture of A, R and S leaves the reactor. Find the operating condition (XA, τ and CR) which maximizes CR, in a mixed flow reacter.

a) The kinetics of a liquid phase decomposition of A is studied in two mixed flow reactors in series, the second unit has the twice the volume of the first. At steady state with a feed containing 1 mol/1(CAo=1 mol/l) and the mean residence time is 96seconds in the first reactor, the concentration of A in the first reactor s 0.5 mol/l and in the second is 0.25 mol/l find the kinetic equation for the decomposition of A

At present the conversion is 66.7% for the elementary second order reaction 2A→2R when operating in an isothermal plug flow reactor with a recycle ratio of unity. Determine the conversion if recycle is shut off.

Gaseous reactant A decomposes as per the following reaction stoichiometry and kineticsA→3R.-rA= 0.60CA mol/l min. Determine the conversion of A in a 50 % A +50% inerts fed at 180 l/min.(330mmol/min) to a 1000 liter mixed flow reactor.

A high molecular weight hydrocarbon stream A is continuously fed to a mixed flow reactor where it thermally cracks into lower molecular materials, collectively called R, as per stoichiometryd A→5R. It is a homogencus gas phase reaction Different extents of cracking obtained by varying the feed rate to the reactor are as follows:

FAo(milli mol/h) 300 1000 3000 5000

CA,OUT (milli mol/l). 16 30 5 60 The reactor volume is 0.1 liter and the feed concentration at the temperature of the reactor is Cac =100 milli mol/l. Find the rate equation which satisfactorily represents the cracking reaction. in the above problem if we ignore density changes, what is the rate equation represents the reaction.

b) A homogenous liquid phase reaction with the given stoichiometry and kinetics A→S,-rA=kCA^2, takes place with 50% conversion in a mixed flow reactor. Find the conversion if this reactor is replaced by another mixed flow reactor having volume 6 times that of the original reactor-all else remain unchanged. Find the conversion if the original reactor is replaced by a plug flow of the same size- all else remains unchanged.

a) We are planning to operate a mixed flow reactor to convert A into R. This is a liquid phase reaction, with the stoichiometryA→R. The rate of reaction is given below. What size of mixed flow reactor is needed to achieve 75% conversion of a feed stream of 1000 moles of A per hour? CA,mol/l. 0.1 0.2 0.3 04 0.5 0.6 0.7 0.8 1 1.3 2. -rA,mol/(l.min). 0.1 0.3 0.5 0.6 0.5 0.25 0.1 0.06 0.05 0.045 0.042

b) The first order reversible liquid phase reaction A⬌R. takes place in batch reactor. After 8 minutes, conversion of A is 33.3% while equilibrium conversion is 66.7%. Find the rate equation to represent this reaction. Take CAo= 0:5 mol/l and CRo=0.