What is PFR
Purchase for Resale (sales classification) PFR..
Does residence time increase or decrease with volume
In size-exclusion chromatography, the residence time of a molecule is related to its volume, which is roughly proportional to its molecular weight. Residence times also affect the performance of continuous fermentors.
What are five major factors that affect reaction rate
Five factors typically affecting the rates of chemical reactions will be explored in this section: the chemical nature of the reacting substances, the state of subdivision (one large lump versus many small particles) of the reactants, the temperature of the reactants, the concentration of the reactants, and the …
What are the assumptions for designing a PFR
Assumptions: Plug flow. Steady state. Constant density (reasonable for some liquids but a 20% error for polymerizations; valid for gases only if there is no pressure drop, no net change in the number of moles, nor any large temperature change)
How do I choose between CSTR and PFR
For between PFRs and CSTRs: With positive order kinetics (ie. reaction rate increases with increasing starting material concentrations) you will always get higher conversion with a PFR. You would choose a CSTR if the reaction was autocatalytic and you didn’t want to reflux a PFR.
What is Backmixing
[′bak ‚mik·siŋ] (chemical engineering) The tendency of reacted chemicals to intermingle with unreacted feed in reactors, such as stirred tanks, packed towers, and baffled tanks.
How do you calculate observed reaction rate
Key PointsReaction rate is calculated using the formula rate = Δ[C]/Δt, where Δ[C] is the change in product concentration during time period Δt.The rate of reaction can be observed by watching the disappearance of a reactant or the appearance of a product over time.More items…
Why is PFR more efficient than CSTR
The chemical reaction proceeds as the reagents travel through the PFR. … A PFR has a higher theoretical efficiency than a CSTR of the same volume. That is, given the same space-time (or residence time), a reaction will proceed to a higher percentage completion in a PFR than in a CSTR.
How does flow rate affect rate of reaction
The higher the flow rate through the membrane, the higher the catalyst activity until reaching a plateau value. The ammonium formation, which is the product of the undesired reaction, is also affected by the flow rate. The shorter the contact time in the porous support, the less ammonium is produced.
How does the K specific reaction rate depend on pressure or does it
KC is an equilibrium constant, and k is specific rate constant and has units of time. The concentration equilibrium constant KC does not. How does the k (specific reaction rate) depend on pressure, or does it? ONLY in very very rare instances at very high pressures such as, 6000 atm is k a function of pressure.
Which has more conversion CSTR or PFR
As can be seen from the figure, the ratio is always positive, indicating that to achieve the same fractional conversion, the volume of a CSTR must be larger than the volume of a PFR. At high fractional conversion values, the volume required for a CSTR increases rapidly compared the the volume of a PFR.
What type of reaction absorbs heat from the surroundings
endothermic processAn endothermic process absorbs heat and cools the surroundings.”
Which would increase the reaction rate
In general, increasing the concentration of a reactant in solution, increasing the surface area of a solid reactant, and increasing the temperature of the reaction system will all increase the rate of a reaction. A reaction can also be sped up by adding a catalyst to the reaction mixture.
What is the full form of PFR
Abbreviation : PFR PFR – Professional Fund Raiser.
What 4 factors affect the rate of a reaction
Reactant concentration, the physical state of the reactants, and surface area, temperature, and the presence of a catalyst are the four main factors that affect reaction rate.