Distillation CSTR Ravi
Distillation CSTR Ravi
Distillation CSTR Ravi
ROLL NO.-2017UIC3128
Continuously Stirred
Tank Reactor
(CSTR)
A continuous stirred tank reactor (CSTR) is a batch reactor equipped with an
impeller or other mixing device to provide efficient mixing. In chemical
engineering the name CSTR is often used to refer an idealised agitated tank
reactor used to model operation variables required to attain a specified
output.
Reactant A is continuously supplied to the reactor with a volumetric flow
rate Fi , a molar concentration(or composition) CAf and a temperature Tf.
The contents of the reactor are mixed with a motorized agitator. An exit
stream, which contains a mixture of both the reactant A and product B, is
withdrawn from the reactor continuously with a volumetric flow rate Fo, a
composition CA and a temperature T. To remove the exothermic heat that is
generated due to the prescribed chemical reaction, a cooling jacket
surrounds the reactor. A coolant stream with a volumetric flow rate Fj and an
inlet temperature Tjin (< T) continuously takes out the heat to maintain the
desired reaction temperature.
Mathematical Modelling Of
CSTR:
𝑑 (𝑝𝑉)
⇒ 𝑑𝑡
= piFi −𝑝𝐹 ± 0
⇒ 𝐴𝑑 (ℎ)
𝑑𝑡
= 𝐹𝑖 − 𝐹 while (pi = p)
pi ,p : densities
of inlet and outlet
streams.
2.Mass Balance of Component A :
⇒𝐴𝑐𝑐𝑢𝑚𝑢𝑙𝑎𝑡𝑖𝑜𝑛
𝑡𝑖𝑚𝑒
𝑜𝑓 𝐴
=
𝑖𝑛𝑝𝑢𝑡 𝑜𝑓 𝐴
𝑡𝑖𝑚𝑒
−
𝑖𝑛𝑝𝑢𝑡 𝑜𝑓 𝐵
𝑡𝑖𝑚𝑒
−
𝐷𝑖𝑠𝑎𝑝𝑝𝑒𝑎𝑟𝑎𝑛𝑐𝑒 𝑜𝑓 𝐴 𝑑𝑢𝑒 𝑡𝑜 𝑟𝑒𝑎𝑐𝑡𝑖𝑜𝑛
𝑡𝑖𝑚𝑒
⇒ 𝑑(𝐶𝑑𝑡𝐴𝑉) = 𝐹𝑖 (𝐶𝐴𝑖 − 𝐶𝐴 ) − 𝑟𝑉
⇒ 𝑉𝑑𝐶
𝑑𝑡
𝐴
= 𝐹𝑖 𝐶𝐴𝑖 − 𝐶𝐴 𝐹𝑖 − 𝑟𝑉
⇒
𝐸
𝑑 (𝐶𝐴 ) 𝐹𝑖 −
= (𝐶𝐴𝑖 − 𝐶𝐴 ) − 𝑘0 𝑒 𝑅𝑇 𝐶𝐴
𝑑𝑡 𝑉
𝐸
(while r = 𝑘0 𝑒 −
𝑅𝑇 𝐶𝐴 𝑉 )
r : Rate of the
reaction/unit volume.
⇒
𝑑(𝑉𝑝𝐶𝑝 𝑇)
= 𝐹𝑖 𝑝𝐶𝑝 𝑇𝑖 − 𝐹𝑝𝐶𝑝 𝑇 − 𝑄 + (−∆𝐻)𝑟𝑉
𝑑𝑡
⇒𝑉 𝑑𝑡 + 𝑇 𝑑𝑡 = 𝐹𝑖 𝑇𝑖 − 𝐹𝑇 − 𝑝𝐶
𝑑𝑇 𝑑𝑉 𝑄
+
(−∆𝐻 )𝑟𝑉
𝑝𝐶𝑝
𝑝
⇒ 𝑉 𝑑𝑇
𝑑𝑡
+ 𝑇(𝐹𝑖 − 𝐹) = 𝐹𝑖 𝑇𝑖 − 𝐹𝑇 −
𝑄
𝑝𝐶
+
(−∆𝐻 )𝑟𝑉
𝑝𝐶𝑝
𝑝
⇒ 𝑉 𝑑𝑇
𝑑𝑡
= 𝐹𝑖 (𝑇𝑖 − 𝑇) −
𝑄
𝑝𝐶
+
(−∆𝐻 )𝑟𝑉
𝑝𝐶𝑝
𝑝
⇒ 𝑑𝑇
𝑑𝑡
𝐹
= 𝑖 (𝑇𝑖 − 𝑇) −
𝑉
𝑄
𝑉𝑝𝐶
+
(−∆𝐻 )𝑟
𝑝𝐶𝑝
𝑝
⇒ 𝑑𝑡 = 𝑉 (𝑇𝑖 − 𝑇) + 𝐽𝑘0𝑒
𝐸
𝑑𝑇 𝐹𝑖 − 𝑄
𝑅𝑇 𝐶𝐴 −
𝑝𝐶𝑝 𝑉
(−∆𝐻 ) 𝐸
−
where J= & r= 𝑘0 𝑒 𝑅𝑇 𝐶𝐴
𝑝𝐶𝑝
3. Output variables: V, CA , T
4. Input variables:
Disturbances: CAi , Fi , Ti
Manipulated variables: Q, F