How Do I Calculate the Height and Diameter of My CSTR Reactor?

In summary, the conversation discusses the calculation of the height and diameter of a CSTR and whether there is a certain ratio that should be followed for better mixing. The individual has tried to find information on this topic, including looking into rules of thumb and searching other books, but to no avail. There is also mention of specific mixing problems, such as slurry, high or low viscosity, and gas-liquid mixture agitation, as well as liquid-liquid mixture agitation for the production of biodiesel. The conversation concludes with a suggestion to start with a tank diameter of 1.5 times the height, with one center-top-entering 45-degree pitched-blade turbine and four vertical tank baffles placed around the tank.
  • #1
princessme
35
0
I have obtained the volume of my CSTR, how do I calculate the height and diameter of it? Is there a certain ratio to adhere to for better mixing? Tried reading up the rules of thumbs but no info on that. Tried searching other books too but to no avail.
 
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  • #2
princessme said:
Is there a certain ratio to adhere to for better mixing?
Slurry? Viscosity is high? Low? Gas-liquid mixture agitation? You might get ideas from searching some specific mixing problems.
 
  • #3
Bystander said:
Slurry? Viscosity is high? Low? Gas-liquid mixture agitation? You might get ideas from searching some specific mixing problems.
Liquid-liquid mixture agitation, for production of biodiesel through esterification/transesterification.
 
  • #5
I'd start with tank diameter D and height 1.5D, with one center-top-entering 45o pitched-blade turbine of diameter D/2 located a distance D/2 from the bottom. Add 4 - 1.4D high, 0.1D wide vertical tank baffles at 90o around the tank periphery.
 

1. What is a CSTR reactor?

A CSTR (Continuous Stirred-Tank Reactor) is a type of reactor used in chemical processes where reactants are continuously fed into the reactor and products are continuously removed. It is a well-mixed vessel with a stirring mechanism to ensure uniform concentration of reactants and products throughout the process.

2. What factors are considered when sizing a CSTR reactor?

The main factors to consider when sizing a CSTR reactor are the desired reaction rate, reactant concentrations, temperature, and the stoichiometry of the reaction. Other factors may include the type of stirrer used, the reactor geometry, and the residence time required for the reaction to reach completion.

3. How do you calculate the volume of a CSTR reactor?

The volume of a CSTR reactor can be calculated by dividing the desired reaction rate by the rate constant of the reaction, and then multiplying it by the residence time. This equation is commonly known as the space-time yield equation: V = F0/(-rA) x τ, where V is the volume, F0 is the volumetric flow rate of feed, -rA is the rate of reaction, and τ is the residence time.

4. What is the ideal residence time for a CSTR reactor?

The ideal residence time for a CSTR reactor depends on the specific reaction being carried out and the desired conversion rate. It is typically determined through experimentation and can range from a few seconds to several hours. A shorter residence time may result in a smaller reactor size, but may also lead to incomplete reactions and lower product yields.

5. Can a CSTR reactor be used for multiple reactions?

Yes, a CSTR reactor can be used for multiple reactions as long as they have similar reaction kinetics and do not interfere with each other. In this case, the reactor size and residence time would need to be adjusted accordingly to ensure both reactions reach completion. Alternatively, a series of CSTRs can also be used to carry out different reactions in sequence.

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