Chemical Reaction Engineering

Question 1

REACTOR TYPE:
CSTR

Answer 1

*Concentration in inlet = outlet
*Constant density
*Irreversible first order reaction
*Volume (Square)
V = (F/-rA) * X

Question 2

REACTOR TYPE:
PFR

Answer 2

*LATERAL / RADIAL MIXNG
*No axial and back mixing
*Lower volume for same conversion as CSTR
*Low operating cost
*High maintenance cost and temperature gradients
*Volume (Under curve)
V = integ (F/-rA) * dX

Question 3

REACTOR TYPE:
PBR

Answer 3

*Volume (Under curve)
W = integ (F/-rA) * dW

Question 4

PROS AND CONS:
*Batch
*FBR
*CSTR
*PFR

Answer 4

*Batch
+ Versatility
- More manual labor

*FBR
+ Temperature distribution
+ Catalyst can be regenerated
+Efficient than catalytic reactors
- Expensive cost and maintenance
- Erosion

*CSTR
+ Continuously produce large amounts of products
+ Temperature distribution
- Large volumes and costs
- Not applicable for slow reactions

*PFR
+ Smaller than CSTR
+ Same Time Space and Conversion as CSTR
- High temperature / Hot spots
-Higher maintenance costs

Question 5

Arrhenius equation

Answer 5

ln(k2/k1) = -E/R(1/T2 - 1/T2)

Question 6

Law of Mass Action

Answer 6

Reaction rate increases with increasing concentration of reactants

Question 7

Reactor

Answer 7

Vessel in which chemical reactions take place

Question 8

A catalyst ___

Answer 8

lowers the activation energy of reacting molecules.

Question 9

A first order reaction requires two equal sized CSTR. The conversion is ____

less when they are connected in series.

more when they are connected in series.

more when they are connected in parallel.

same whether they are connected in series or in parallel.

Answer 9

more when they are connected in series.

Question 9

Autoclave

Answer 9

high pressure batch reactor.

Question 9

The rate constant of a chemical reaction decreases by decreasing the ___

Answer 9

temperature

Question 10

In an exothermic chemical reaction, the reactants compared to the products have ____

Answer 10

more energy

Question 11

Radioactive decay follows __________ kinetics.

Answer 11

first order kinetics

Question 12

Conversion increases with increase in temperature in case of a an __________ reaction.

Answer 12

reversible endothermic reaction

Question 13

For nearly isothermal operation involving large reaction time in a liquid-phase reaction, the most suitable reactor is a __________ reactor.

Answer 13

stirred tank reactor

Question 14

The equilibrium constant of a catalytic chemical reaction __________ due to the presence of a catalyst.

Answer 14

remains constant

Question 15

The rate constant of a chemical reaction increases by increasing the ___

Answer 15

temperature

Question 16

Rate determining step in a reaction consisting of a number of steps in series is the __________ step.

Answer 16

slowest

Question 17

The reaction in which one of the products of reaction acts as a catalyst is called a/an __________ reaction.

Answer 17

autocatalytic

Question 18

Why use CSTR over PFR?

Answer 18

*more uniform operating conditions.
*operation at optimum temperature for a long reaction time.
* higher overall selectivity for a first order consecutive reaction.

Question 19

The reaction in which the rate equation corresponds to a stoichiometric equation, is called a/an __________ reaction.

Answer 19

elementary

Question 20

A chemical reaction occurs when the energy of the reacting molecules is __________ the activation energy of the reaction.

Answer 20

equal to or more than