Your Question:

An irreversible reaction A → B + C is performed in two PFR connected in series. The first PFR is adiabatic, and the second PFR is isothermal. The feed at a concentration of 300 g/L enters the first PFR at 25 °C and the standard heat of reaction is -200 cal/(g). The density of the feed is 0.95 kg/L and the volumetric flow rate is 0.8 m³/h. The heat capacity of the of the liquid is 0.92 cal/(g*°C). The first order rate constant depends on the temperature is k = 3.0 +0.6(T25) h¹.

PFR-1

a) Determine the volume requirements for both the adiabatic and isothermal PFR required to achieve 90% conversion of A to B

b) What are the heat transfer requirements for the isothermal segement of the reactor? Is thermal energy added to or removed from the isothermal PFR?

Step By Step Answers with Explanation

Step 2: Calculate the rate constant at 25 °C (k25)

• k25 = 3.0 + 0.6(25) = 18 h⁻¹

Step 5: Calculate the volume (V) of the adiabatic PFR-1

• V = Q * τ = 2.22 * 10⁻⁵ m³/s * 4.44 h = 0.0099 m³ = 9.9 L

Step 8: Calculate the volume (V) of the isothermal PFR-2

• V = Q * τ = 2.22 * 10⁻⁵ m³/s * 1.67 h = 0.0037 m³ = 3.7 L

Step 2: Calculate the heat generated in the isothermal PFR-2

• Heat generated (Q) = ΔH * m

• Since ΔH is negative, the heat transfer required is positive, indicating that thermal energy needs to be removed from the isothermal PFR-2.

Therefore, the heat transfer required for the isothermal PFR-2 is positive, indicating that thermal energy needs to be removed from the reactor.