0
Why volume PFR less than CSTR for same conversion and reaction rate?
Wiki User
∙ 13y ago
The reason that a PFR requires less volume than a CSTR is the difference in residence time distribution between the reactors. Residence time is the amount of time molecules spend in the reactor which equal to v/vo (v=volume of the reactor and v0 is volumetric flow rate). Let us assume that we design a PFR and CSTR that have similar residence time i.e. ratio of volume v and v0 is the same and we are pumping about 100 molecule per minute to each reactor. In the case of PFR, all the 100 molecules will spend exactly the same time inside the reactor (v/v0). In the case of CSTR, things are little more complicated, once the 100 molecule hit the CSTR, they mixted instantaneously and thus some of these 100 molecules will leave from the reactor exit stream very early i.e. will spend much less time inside the reactor (less the v/v0) and of course some these 100 molecule will spend more time making the average residence time the same as the PFR. Therefore, with the chance that molecules will spend shorter time in CSTR, we try to compensate for that effect by making bigger reactors so the ratio of these molecules spending short period of time inside the reactor less and thus its performance is comparable to the PFR.
Very logical and easy to understand explanation. But how to prove series of CSTR equals to one PFR which is having a volume of sum of all CSTRs?
Lottie Von
Add your answer:
Earn +20 pts
If a chemical reaction has reached equilibrium and you lower the pressure of the system while keeping the temperature constant what happens to the equilibrium of the reaction?
If all the reactants occupy more volume than all of the products, the reverse reaction will be favored. If all the reactants occupy less volume than all of the products, the forward reaction will be favored. If the products and reagents have the same volume, the equilibrium will not change.
How in terms of collision theory how a decrease in concentration can change the rate of a precipitation reaction?
Decrease in conc. means decrease in no. of molecules per unit volume. Since, molecules or atoms will less in number, the no. of colliding particles will be less. This will lead to decreased precipitation
Volume of warm air weighs less than an equal volume of cold air because?
It's less dense
Does water with a greater volume cool faster than water with a less volume?
NO
What At low temperatures and pressure how does the volume of a real gas compare with the volume of an ideal gas under the same conditions?
It is less
Diffeerence between CSTR and PFR on volume baises?
For simple understanding PFR can be imagined as multiple CSTR's in series. PFR has benefits of higher conversion rates, product uniformity & less energy losses. CSTR stands for Continuously Stirred Tank Reactor. PFR stands for Plug Flow Reactor.
Why PFR requires less volume than CSTR for same conversion and reaction rates?
The reason that a PFR requires less volume than a CSTR is the difference in residence time distribution between the reactors. Residence time is the amount of time molecules spend in the reactor which equal to v/vo (v=volume of the reactor and v0 is volumetric flow rate). Let us assume that we design a PFR and CSTR that have similar residence time i.e. ratio of volume v and v0 is the same and we are pumping about 100 molecule per minute to each reactor. In the case of PFR, all the 100 molecules will spend exactly the same time inside the reactor (v/v0). In the case of CSTR, things are little more complicated, once the 100 molecule hit the CSTR, they mixted instantaneously and thus some of these 100 molecules will leave from the reactor exit stream very early i.e. will spend much less time inside the reactor (less the v/v0) and of course some these 100 molecule will spend more time making the average residence time the same as the PFR. Therefore, with the chance that molecules will spend shorter time in CSTR, we try to compensate for that effect by making bigger reactors so the ratio of these molecules spending short period of time inside the reactor less and thus its performance is comparable to the PFR. Very logical and easy to understand explanation. But how to prove series of CSTR equals to one PFR which is having a volume of sum of all CSTRs?
Is volume conserved in a reaction between distilled water and ethanol?
No because they have different densities so the volume of the two combined will be slightly less.
If a chemical reaction has reached equilibrium and you lower the pressure of the system while keeping the temperature constant what happens to the equilibrium of the reaction?
If all the reactants occupy more volume than all of the products, the reverse reaction will be favored. If all the reactants occupy less volume than all of the products, the forward reaction will be favored. If the products and reagents have the same volume, the equilibrium will not change.
250 grams of pasta convert to ml?
It depends on the density of whatever it is you are measuring. g is a measurement of weight. ml is a measurement of volume. If it's water, then 1g is precisely 1ml.... so 250g = 250ml. If it's something less dense then it could be way more or less.
A comparison of amount of energy before a conversion with the amount of useful energy after a conversion?
Usually, the amount of useful energy after a conversion will be less than the original energy. In no case can it be more.Usually, the amount of useful energy after a conversion will be less than the original energy. In no case can it be more.Usually, the amount of useful energy after a conversion will be less than the original energy. In no case can it be more.Usually, the amount of useful energy after a conversion will be less than the original energy. In no case can it be more.
What is also less if the mass is less in a volume?
Density. Mass is the product of volume and density, so therefore density is the ratio of mass to volume.
What material used to decrease the rate of reaction is?
Water for one. If a reaction is diluted, the components of the reaction are less likely to contact one another. This will mean that they will be also less likely to continue a reaction.
How in terms of collision theory how a decrease in concentration can change the rate of a precipitation reaction?
Decrease in conc. means decrease in no. of molecules per unit volume. Since, molecules or atoms will less in number, the no. of colliding particles will be less. This will lead to decreased precipitation
How many pounds are in a peck?
None, since there can be no conversion. A pound is a measure of mass. A peck is a measure of volume - in the US a dry measure equivalent to 2 gallons. The two measure different things and, according to basic principles of dimensional analysis, conversion from one to the other is not valid. The masses of equal volumes of the two substances will clearly be very different. So there is no direct conversion between mass and volume: you need to know the density of the substance to enable you to carry out the conversion.
Volume of warm air weighs less than an equal volume of cold air because?
It's less dense
What is the product of the conversion of ammonia into a less toxic substance?
UREA
