AdvancedTopic 82 of 100Materials & Chemical
Batch and CSTR reactors
Ideal mixed reactors for different operation modes.
In depth
Batch reactors are charged, reacted and emptied (flexible, small scale). A CSTR is well mixed with uniform composition equal to exit, steady state: V=F_A0X/(-r_A). Series CSTRs approach plug flow. Pros: good temperature control; cons: lower conversion per volume for positive-order reactions.
Key points
- Space time τ=V/v₀
- Perfect mixing
- Start-up and transients
ExampleA polymerisation tank stirred continuously is modelled as a CSTR.
What is Batch and CSTR reactors?
Ideal mixed reactors for different operation modes.
Why is it important to understand batch and CSTR reactors?
Batch and stirred tank reactors are the most common reactors in industry, and their ideal models are the starting point for design.
What is a CSTR?
A continuous stirred tank reactor in which the contents are perfectly mixed, so the outlet composition equals the composition inside the tank.
What is the advantage of a batch reactor?
It is flexible for small production runs and multiple products, but it has downtime for filling and emptying between batches.
How is Batch and CSTR reactors used in practice?
Typical applications include running a small-volume specialty chemical batch in a stirred tank, designing a continuous stirred tank reactor for a large-volume product and choosing between batch and continuous operation for a new product.
What should I learn before Batch and CSTR reactors?
Study "Arrhenius equation" first (topic 81 of 100 in Materials & Chemical). It covers the groundwork this topic builds on.
What are the key points of Batch and CSTR reactors?
Space time τ=V/v₀. Perfect mixing. Start-up and transients.
Can you give an example of Batch and CSTR reactors?
A polymerisation tank stirred continuously is modelled as a CSTR.
What comes after Batch and CSTR reactors?
The next topic is "Plug flow reactors", which builds directly on this one.
How difficult is Batch and CSTR reactors?
It is classed as Advanced in Materials & Chemical (topic 82 of 100). It is an advanced topic. It assumes you are comfortable with the intermediate topics in Materials & Chemical.