Kinetics Patrick Cable, Dat Huynh, Greg Kalinyak, Ryan Leech, Wright Makambi, Ronak Ujla

Batch Reactor No inlet or outlet flow Reactants are placed inside the reactor and allowed to react over a set period of time Advantages High Conversion can be achieved if allowed a long reaction time Versatile, and can be quickly adapted for different products Disadvantages Difficult to use for large scale production High cost of labor per unit of production https://www.researchgate.net/figure/Schematic-diagram-of-batch-reactor_fig9_259169382

Batch Reactor Design Equations Input - Output + Generation = Accumulation Input = Output = 0 https://www.researchgate.net/figure/Schematic-diagram-of-batch-reactor_fig9_259169382

Semi-Batch Reactor In between a CSTR and a Batch reactor No outlet flow, only an inlet flow Reactants are fed in at a set rate in either a two phase reaction or to prevent unwanted side reactions Advantages Minimize side reactions Good temperature control Disadvantages Not good for large scale production High Cost Reactor operation can be difficult to analyze https://www.safaribooksonline.com/library/view/essentials-of-chemical/9780132317191/h4_699.html?orpq

Semi-Batch Reactor Design Equations Input - Output + Generation = Accumulation Due to the change in both Volume over time and Concentration with time, solving the equations needs the use of a computer Need to set up an equation for each component using the mass balance and another for the volume and solve simultaneously https://www.safaribooksonline.com/library/view/essentials-of-chemical/9780132317191/h4_699.html?orpq

Continuous Stir Tank Reactor (CSTR) A constant inlet and outlet flow that is continuously mixed The concentration inside the reactor is the same as the outlet Advantages Cheap to construct Large amounts of product Temperature Control is easy Disadvantages Conversion of reactor to product is small compared to other reactors Deadzones can occur if mixing isn’t done well. https://www.researchgate.net/figure/Schematic-representation-of-the-continuous-stirred-tank-reactor-CSTR

CSTR Design Equation Input - Output + Generation = Accumulation https://www.researchgate.net/figure/Schematic-representation-of-the-continuous-stirred-tank-reactor-CSTR

Slurry Reactors Multiphase reactor where gas is bubbled through a solvent containing catalyst particles Can be operated in batch or continuously Advantages Good temperature control Large heat capacity Good catalyst control and extended life Common Applications - Hydrogenation, Oxidation, Hydroformylation, Polymers Elements of Chemical Reaction Engineering, 5th Edition

Steps in Slurry Reactor Adsorption from gas phase to bubble surface Diffusion from bubble surface to bulk Diffusion from bulk to catalyst surface Diffusion from catalyst surface into porous catalyst Reaction with catalyst Elements of Chemical Reaction Engineering, 5th Edition

Design Equation Derivation Rearranging... Elements of Chemical Reaction Engineering, 5th Edition

Fluidized Bed Reactors (FBR) Similar flow pattern to slurry reactors Bed of solid catalyst, liquid or gas pumped/forced up thru the bed, suspending catalyst particles “Fluidized” catalyst particles Useful for: Catalytic cracking of petroleum naphthas for gasoline Advantages: Excellent mixing/contact of catalyst and reactants Uniform temperature Continuous regeneration of catalyst Disadvantages: Fluid mechanics not well known Need to overcome gravity to suspend the catalyst/move the fluid Increased size requirements due to expansion Elements of Chemical Reaction Engineering, 5th Edition

FBR Considerations Velocity/flow rate of fluid/gas must be great enough to suspend solid catalyst, but slow enough that the solid catalyst is not carried out of the reactor with the fluid/gas Porosity of catalytic bed prior to (and post) fluidization Mass transfer rates must be taken into account Elements of Chemical Reaction Engineering, 5th Edition

Bubbling Bed Model by Kunii & Levenspiel Reactant gas bubbles up through the reactor MT of reactant occurs, through the wall of the bubble, onto the solid catalyst particles, which convert to product MT of product occurs, back through the wall of the bubble, and the resultant reactant/product mixture is carried out of the reactor Conversion depends on rate of MT in/out of bubbles, rate of reaction, as well as on the residence time of reactant in the reactor. Elements of Chemical Reaction Engineering, 5th Edition

FBR Design Parameters Porosity of bed at minimum fluidization Minimum fluidization velocity Maximum fluidization velocity Bubble size Velocity of bubble rise Fraction of total bed occupied by bubbles Fraction of the bed consisting as wakes Volume of catalyst in bubbles, clouds and emulsion Mass of solid catalyst

Packed Bed Reactor (PBR) Similar to the previous reactors. Contains a compartment for the catalyst. Heterogeneous reactions. Considerations Pressure drop Catalyst size Most common found in industry Applications: Methanol synthesis/oxidation Styrene production Wastewater treatment https://www.comsol.com/blogs/packed-bed-reactor/

PBR cont... Advantages High Conversion per weight of catalyst. Easy to build. More contact between reactant and catalyst. More effective at high temperatures and pressures. Disadvantages No temperature control. Difficulty in replacing catalyst. Channeling of gas stream. https://www.comsol.com/blogs/packed-bed-reactor/

PBR Design equations Unlike a PFR the volume of the reactor is no longer relevant. Catalyst weight and density https://www.comsol.com/blogs/packed-bed-reactor/

Plug Flow Reactor (PFR) Reactors that consist of a cylindrical pipe where reactants flow in and products flow out Plug flow means no radial changes in velocity, temperature, or concentration Good for various applications in gas and liquid systems Gasoline Production Ammonia Synthesis Advantages Mechanically simple and easy to maintain High conversion rate per reactor volume Disadvantages Reactor temperature difficult to control Undesirable thermal gradients Sourced from: https://homes.nano.aau.dk Elements of Chemical Reaction Engineering, 5th Edition

PFR Design Equations Elements of Chemical Reaction Engineering, 5th Edition

Laminar Flow Reactor (LFR) Very similar to PFR except it is a tube with laminar flow which means radial changes in velocity Generally been used in research for multiphase reactions Sourced from: https://www.researchgate.net

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